//
// Internet Printing Protocol functions for CUPS.
//
// Copyright © 2021-2026 by OpenPrinting.
// Copyright © 2007-2021 by Apple Inc.
// Copyright © 1997-2007 by Easy Software Products, all rights reserved.
//
// Licensed under Apache License v2.0.  See the file "LICENSE" for more
// information.
//

#include "cups-private.h"
#include <regex.h>
#ifdef _WIN32
#  include <io.h>
#endif // _WIN32


//
// Local globals...
//

static cups_mutex_t	regex_mutex = CUPS_MUTEX_INITIALIZER;
					// Mutex for regular expressions
static bool		regex_init = false;
					// Have regular expressions been initialized?
static regex_t		lang_regex;	// Regular expression for naturalLanguage
static regex_t		mime_regex;	// Regular expression for mimeMediaType


//
// Local functions...
//

static ipp_attribute_t	*ipp_add_attr(ipp_t *ipp, const char *name, ipp_tag_t group_tag, ipp_tag_t value_tag, size_t num_values);
static void		ipp_free_values(ipp_attribute_t *attr, size_t element, size_t count);
static char		*ipp_get_code(const char *locale, char *buffer, size_t bufsize) _CUPS_NONNULL(1,2);
static bool		ipp_is_valid_language(const char *name, const char *lang);
static bool		ipp_is_valid_mimetype(const char *name, const char *type);
static char		*ipp_lang_code(const char *locale, char *buffer, size_t bufsize) _CUPS_NONNULL(1,2);
static size_t		ipp_length(ipp_t *ipp, int collection);
static ssize_t		ipp_read_file(int *fd, ipp_uchar_t *buffer, size_t length);
static ssize_t		ipp_read_http(http_t *http, ipp_uchar_t *buffer, size_t length);
static ipp_state_t	ipp_read_io(void *src, ipp_io_cb_t cb, bool blocking, ipp_t *parent, ipp_t *ipp, int depth);
static bool		ipp_regex_begin(void);
static void		ipp_regex_end(void);
static void		ipp_set_error(ipp_status_t status, const char *format, ...);
static _ipp_value_t	*ipp_set_value(ipp_t *ipp, ipp_attribute_t **attr, size_t element);
static ssize_t		ipp_write_file(int *fd, ipp_uchar_t *buffer, size_t length);


//
// '_cupsBufferGet()' - Get a read/write buffer.
//

char *					// O - Buffer
_cupsBufferGet(size_t size)		// I - Size required
{
  _cups_buffer_t	*buffer;	// Current buffer
  _cups_globals_t	*cg = _cupsGlobals();
					// Global data


  for (buffer = cg->cups_buffers; buffer; buffer = buffer->next)
    if (!buffer->used && buffer->size >= size)
      break;

  if (!buffer)
  {
    if ((buffer = malloc(sizeof(_cups_buffer_t) + size - 1)) == NULL)
      return (NULL);

    buffer->next     = cg->cups_buffers;
    buffer->size     = size;
    cg->cups_buffers = buffer;
  }

  buffer->used = 1;

  return (buffer->d);
}


//
// '_cupsBufferRelease()' - Release a read/write buffer.
//

void
_cupsBufferRelease(char *b)		// I - Buffer to release
{
  _cups_buffer_t	*buffer;	// Buffer


  // Mark this buffer as unused...
  buffer       = (_cups_buffer_t *)(b - offsetof(_cups_buffer_t, d));
  buffer->used = 0;
}


//
// 'ippAddBoolean()' - Add a boolean attribute to an IPP message.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "group" argument specifies the IPP attribute group tag: none
// (`IPP_TAG_ZERO`, for member attributes), document (`IPP_TAG_DOCUMENT`),
// event notification (`IPP_TAG_EVENT_NOTIFICATION`), operation
// (`IPP_TAG_OPERATION`), printer (`IPP_TAG_PRINTER`), subscription
// (`IPP_TAG_SUBSCRIPTION`), or unsupported (`IPP_TAG_UNSUPPORTED_GROUP`).
//

ipp_attribute_t *			// O - New attribute
ippAddBoolean(ipp_t      *ipp,		// I - IPP message
              ipp_tag_t  group,		// I - IPP group
              const char *name,		// I - Name of attribute
              bool       value)		// I - Value of attribute
{
  ipp_attribute_t	*attr;		// New attribute


  DEBUG_printf("ippAddBoolean(ipp=%p, group=%02x(%s), name=\"%s\", value=%d)", (void *)ipp, group, ippTagString(group), name, value);

  // Range check input...
  if (!ipp || !name || group < IPP_TAG_ZERO || group == IPP_TAG_END || group >= IPP_TAG_UNSUPPORTED_VALUE)
    return (NULL);

  // Create the attribute...
  if ((attr = ipp_add_attr(ipp, name, group, IPP_TAG_BOOLEAN, 1)) == NULL)
    return (NULL);

  attr->values[0].boolean = value;

  return (attr);
}


//
// 'ippAddBooleans()' - Add an array of boolean values.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "group" argument specifies the IPP attribute group tag: none
// (`IPP_TAG_ZERO`, for member attributes), document (`IPP_TAG_DOCUMENT`),
// event notification (`IPP_TAG_EVENT_NOTIFICATION`), operation
// (`IPP_TAG_OPERATION`), printer (`IPP_TAG_PRINTER`), subscription
// (`IPP_TAG_SUBSCRIPTION`), or unsupported (`IPP_TAG_UNSUPPORTED_GROUP`).
//

ipp_attribute_t *			// O - New attribute
ippAddBooleans(ipp_t      *ipp,		// I - IPP message
               ipp_tag_t  group,	// I - IPP group
	       const char *name,	// I - Name of attribute
	       size_t     num_values,	// I - Number of values
	       const bool *values)	// I - Values
{
  size_t		i;		// Looping var
  ipp_attribute_t	*attr;		// New attribute
  _ipp_value_t		*value;		// Current value


  DEBUG_printf("ippAddBooleans(ipp=%p, group=%02x(%s), name=\"%s\", num_values=%u, values=%p)", (void *)ipp, group, ippTagString(group), name, (unsigned)num_values, (void *)values);

  // Range check input...
  if (!ipp || !name || group < IPP_TAG_ZERO || group == IPP_TAG_END || group >= IPP_TAG_UNSUPPORTED_VALUE || num_values < 1)
    return (NULL);

  // Create the attribute...
  if ((attr = ipp_add_attr(ipp, name, group, IPP_TAG_BOOLEAN, num_values)) == NULL)
    return (NULL);

  if (values)
  {
    for (i = num_values, value = attr->values; i > 0; i --, value ++)
      value->boolean = *values++;
  }

  return (attr);
}


//
// 'ippAddCollection()' - Add a collection value.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or @link ippNewResponse@ functions.
//
// The "group" argument specifies the IPP attribute group tag: none
// (`IPP_TAG_ZERO`, for member attributes), document (`IPP_TAG_DOCUMENT`),
// event notification (`IPP_TAG_EVENT_NOTIFICATION`), operation
// (`IPP_TAG_OPERATION`), printer (`IPP_TAG_PRINTER`), subscription
// (`IPP_TAG_SUBSCRIPTION`), or unsupported (`IPP_TAG_UNSUPPORTED_GROUP`).
//
// The "name" argument specifies the name of the attribute, while the "value"
// argument provides an IPP message containing the collection member attributes.
//
// > **Note:** You must call the @link ippDelete@ function on the "value"
// > argument to make sure the memory used by the value is released.
//

ipp_attribute_t *			// O - New attribute
ippAddCollection(ipp_t      *ipp,	// I - IPP message
                 ipp_tag_t  group,	// I - IPP group
		 const char *name,	// I - Name of attribute
		 ipp_t      *value)	// I - Value
{
  ipp_attribute_t	*attr;		// New attribute


  DEBUG_printf("ippAddCollection(ipp=%p, group=%02x(%s), name=\"%s\", value=%p)", (void *)ipp, group, ippTagString(group), name, (void *)value);

  // Range check input...
  if (!ipp || !name || group < IPP_TAG_ZERO || group == IPP_TAG_END || group >= IPP_TAG_UNSUPPORTED_VALUE)
    return (NULL);

  // Create the attribute...
  if ((attr = ipp_add_attr(ipp, name, group, IPP_TAG_BEGIN_COLLECTION, 1)) == NULL)
    return (NULL);

  attr->values[0].collection = value;

  if (value)
    value->use ++;

  return (attr);
}


//
// 'ippAddCollections()' - Add an array of collection values.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "group" argument specifies the IPP attribute group tag: none
// (`IPP_TAG_ZERO`, for member attributes), document (`IPP_TAG_DOCUMENT`),
// event notification (`IPP_TAG_EVENT_NOTIFICATION`), operation
// (`IPP_TAG_OPERATION`), printer (`IPP_TAG_PRINTER`), subscription
// (`IPP_TAG_SUBSCRIPTION`), or unsupported (`IPP_TAG_UNSUPPORTED_GROUP`).
//
// The "name" argument specifies the name of the attribute, while the
// "num_values" and "values" arguments provide IPP messages containing the
// collection member attributes for each value.
//
// > **Note:** You must call the @link ippDelete@ function on each of the
// > "values" arguments to make sure the memory used by the value is released.
//

ipp_attribute_t *			// O - New attribute
ippAddCollections(
    ipp_t       *ipp,			// I - IPP message
    ipp_tag_t   group,			// I - IPP group
    const char  *name,			// I - Name of attribute
    size_t      num_values,		// I - Number of values
    const ipp_t **values)		// I - Values
{
  size_t		i;		// Looping var
  ipp_attribute_t	*attr;		// New attribute
  _ipp_value_t		*value;		// Current value


  DEBUG_printf("ippAddCollections(ipp=%p, group=%02x(%s), name=\"%s\", num_values=%u, values=%p)", (void *)ipp, group, ippTagString(group), name, (unsigned)num_values, (void *)values);

  // Range check input...
  if (!ipp || !name || group < IPP_TAG_ZERO || group == IPP_TAG_END || group >= IPP_TAG_UNSUPPORTED_VALUE || num_values < 1)
    return (NULL);

  // Create the attribute...
  if ((attr = ipp_add_attr(ipp, name, group, IPP_TAG_BEGIN_COLLECTION, num_values)) == NULL)
    return (NULL);

  if (values)
  {
    for (i = num_values, value = attr->values; i > 0; i --, value ++)
    {
      value->collection = (ipp_t *)*values++;
      value->collection->use ++;
    }
  }

  return (attr);
}


//
// 'ippAddCredentialsString()' - Add a credentials string attribute to an IPP message.
//
// This function adds a 1setOf text attribute to an IPP message corresponding to
// the specified credentials string.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "group" argument specifies the IPP attribute group tag: none
// (`IPP_TAG_ZERO`, for member attributes), document (`IPP_TAG_DOCUMENT`),
// event notification (`IPP_TAG_EVENT_NOTIFICATION`), operation
// (`IPP_TAG_OPERATION`), printer (`IPP_TAG_PRINTER`), subscription
// (`IPP_TAG_SUBSCRIPTION`), or unsupported (`IPP_TAG_UNSUPPORTED_GROUP`).
//

ipp_attribute_t *			// O - New attribute
ippAddCredentialsString(
    ipp_t      *ipp,			// I - IPP message
    ipp_tag_t  group,			// I - IPP group
    const char *name,			// I - Attribute name
    const char *credentials)		// I - Credentials string
{
  ipp_attribute_t	*attr;		// New attribute
  char			*cvalue,	// Copied value
			*cstart,	// Start of value
			*cptr;		// Pointer into copied value
  size_t		i,		// Looping var
			num_values;	// Number of values


  // Range check input...
  if (!ipp || !name || !credentials)
    return (NULL);

  // Copy the value string and figure out the number of values...
  if ((cvalue = strdup(credentials)) == NULL)
    return (NULL);

  for (num_values = 0, cptr = cvalue; cptr;)
  {
    // Find the next delimiter
    if (*cptr && *cptr != '\r' && *cptr != '\n')
      num_values ++;

    cstart = cptr;
    if ((cptr = strchr(cstart, '\r')) != NULL)
    {
      // Skip CR or CR LF
      if (cptr[1] == '\n')
        cptr += 2;
      else
        cptr ++;
    }
    else if ((cptr = strchr(cstart, '\n')) != NULL)
    {
      // Skip LF
      cptr ++;
    }
  }

  // Create the empty attribute and copy the values...
  if ((attr = ippAddStrings(ipp, group, IPP_TAG_TEXT, name, num_values, NULL, NULL)) != NULL)
  {
    for (i = 0, cptr = cvalue; cptr && i < num_values;)
    {
      cstart = cptr;
      if ((cptr = strchr(cptr, '\r')) != NULL)
      {
        // Terminate on CR
        *cptr++ = '\0';
        if (*cptr == '\n')
          cptr ++;			// Skip LF
      }
      else if ((cptr = strchr(cstart, '\n')) != NULL)
      {
        // Terminate on LF
        *cptr++ = '\0';
      }

      if (*cstart)
        attr->values[i++].string.text = _cupsStrAlloc(cstart);
    }
  }

  // Free the copied string and return...
  free(cvalue);

  return (attr);
}


//
// 'ippAddDate()' - Add a dateTime attribute to an IPP message.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "group" argument specifies the IPP attribute group tag: none
// (`IPP_TAG_ZERO`, for member attributes), document (`IPP_TAG_DOCUMENT`),
// event notification (`IPP_TAG_EVENT_NOTIFICATION`), operation
// (`IPP_TAG_OPERATION`), printer (`IPP_TAG_PRINTER`), subscription
// (`IPP_TAG_SUBSCRIPTION`), or unsupported (`IPP_TAG_UNSUPPORTED_GROUP`).
//

ipp_attribute_t *			// O - New attribute
ippAddDate(ipp_t             *ipp,	// I - IPP message
           ipp_tag_t         group,	// I - IPP group
	   const char        *name,	// I - Name of attribute
	   const ipp_uchar_t *value)	// I - Value
{
  ipp_attribute_t	*attr;		// New attribute


  DEBUG_printf("ippAddDate(ipp=%p, group=%02x(%s), name=\"%s\", value=%p)", (void *)ipp, group, ippTagString(group), name, (void *)value);

  // Range check input...
  if (!ipp || !name || !value || group < IPP_TAG_ZERO || group == IPP_TAG_END || group >= IPP_TAG_UNSUPPORTED_VALUE)
    return (NULL);

  // Create the attribute...
  if ((attr = ipp_add_attr(ipp, name, group, IPP_TAG_DATE, 1)) == NULL)
    return (NULL);

  memcpy(attr->values[0].date, value, 11);

  return (attr);
}


//
// 'ippAddInteger()' - Add a integer attribute to an IPP message.
//
// This function adds an integer or enum attribute to an IPP message.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "group" argument specifies the IPP attribute group tag: none
// (`IPP_TAG_ZERO`, for member attributes), document (`IPP_TAG_DOCUMENT`),
// event notification (`IPP_TAG_EVENT_NOTIFICATION`), operation
// (`IPP_TAG_OPERATION`), printer (`IPP_TAG_PRINTER`), subscription
// (`IPP_TAG_SUBSCRIPTION`), or unsupported (`IPP_TAG_UNSUPPORTED_GROUP`).
//
// Supported values include enum (`IPP_TAG_ENUM`) and integer
// (`IPP_TAG_INTEGER`).
//

ipp_attribute_t *			// O - New attribute
ippAddInteger(ipp_t      *ipp,		// I - IPP message
              ipp_tag_t  group,		// I - IPP group
	      ipp_tag_t  value_tag,	// I - Type of attribute
              const char *name,		// I - Name of attribute
              int        value)		// I - Value of attribute
{
  ipp_attribute_t	*attr;		// New attribute


  DEBUG_printf("ippAddInteger(ipp=%p, group=%02x(%s), type=%02x(%s), name=\"%s\", value=%d)", (void *)ipp, group, ippTagString(group), value_tag, ippTagString(value_tag), name, value);

  value_tag &= IPP_TAG_CUPS_MASK;

  // Special-case for legacy usage: map out-of-band attributes to new ippAddOutOfBand function...
  if (value_tag >= IPP_TAG_UNSUPPORTED_VALUE && value_tag <= IPP_TAG_ADMINDEFINE)
    return (ippAddOutOfBand(ipp, group, value_tag, name));

  // Range check input...
  if (!ipp || !name || group < IPP_TAG_ZERO || group == IPP_TAG_END || group >= IPP_TAG_UNSUPPORTED_VALUE || (value_tag != IPP_TAG_INTEGER && value_tag != IPP_TAG_ENUM))
    return (NULL);

  // Create the attribute...
  if ((attr = ipp_add_attr(ipp, name, group, value_tag, 1)) == NULL)
    return (NULL);

  attr->values[0].integer = value;

  return (attr);
}


//
// 'ippAddIntegers()' - Add an array of integer values.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "group" argument specifies the IPP attribute group tag: none
// (`IPP_TAG_ZERO`, for member attributes), document (`IPP_TAG_DOCUMENT`),
// event notification (`IPP_TAG_EVENT_NOTIFICATION`), operation
// (`IPP_TAG_OPERATION`), printer (`IPP_TAG_PRINTER`), subscription
// (`IPP_TAG_SUBSCRIPTION`), or unsupported (`IPP_TAG_UNSUPPORTED_GROUP`).
//
// Supported values include enum (`IPP_TAG_ENUM`) and integer
// (`IPP_TAG_INTEGER`).
//

ipp_attribute_t *			// O - New attribute
ippAddIntegers(ipp_t      *ipp,		// I - IPP message
               ipp_tag_t  group,	// I - IPP group
	       ipp_tag_t  value_tag,	// I - Type of attribute
	       const char *name,	// I - Name of attribute
	       size_t     num_values,	// I - Number of values
	       const int  *values)	// I - Values
{
  size_t		i;		// Looping var
  ipp_attribute_t	*attr;		// New attribute
  _ipp_value_t		*value;		// Current value


  DEBUG_printf("ippAddIntegers(ipp=%p, group=%02x(%s), type=%02x(%s), name=\"%s\", num_values=%u, values=%p)", (void *)ipp, group, ippTagString(group), value_tag, ippTagString(value_tag), name, (unsigned)num_values, (void *)values);

  value_tag &= IPP_TAG_CUPS_MASK;

  // Range check input...
  if (!ipp || !name || group < IPP_TAG_ZERO || group == IPP_TAG_END || group >= IPP_TAG_UNSUPPORTED_VALUE || (value_tag != IPP_TAG_INTEGER && value_tag != IPP_TAG_ENUM) || num_values < 1)
    return (NULL);

  // Create the attribute...
  if ((attr = ipp_add_attr(ipp, name, group, value_tag, num_values)) == NULL)
    return (NULL);

  if (values)
  {
    for (i = num_values, value = attr->values; i > 0; i --, value ++)
      value->integer = *values++;
  }

  return (attr);
}


//
// 'ippAddOctetString()' - Add an octetString value to an IPP message.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "group" argument specifies the IPP attribute group tag: none
// (`IPP_TAG_ZERO`, for member attributes), document (`IPP_TAG_DOCUMENT`),
// event notification (`IPP_TAG_EVENT_NOTIFICATION`), operation
// (`IPP_TAG_OPERATION`), printer (`IPP_TAG_PRINTER`), subscription
// (`IPP_TAG_SUBSCRIPTION`), or unsupported (`IPP_TAG_UNSUPPORTED_GROUP`).
//

ipp_attribute_t	*			// O - New attribute
ippAddOctetString(ipp_t      *ipp,	// I - IPP message
                  ipp_tag_t  group,	// I - IPP group
                  const char *name,	// I - Name of attribute
                  const void *data,	// I - octetString data
		  size_t     datalen)	// I - Length of data in bytes
{
  ipp_attribute_t	*attr;		// New attribute


  // Range check input...
  if (!ipp || !name || group < IPP_TAG_ZERO || group == IPP_TAG_END || group >= IPP_TAG_UNSUPPORTED_VALUE || datalen > IPP_MAX_LENGTH)
    return (NULL);

  if ((attr = ipp_add_attr(ipp, name, group, IPP_TAG_STRING, 1)) == NULL)
    return (NULL);

  // Initialize the attribute data...
  attr->values[0].unknown.length = datalen;

  if (data)
  {
    if ((attr->values[0].unknown.data = malloc((size_t)datalen)) == NULL)
    {
      ippDeleteAttribute(ipp, attr);
      return (NULL);
    }

    memcpy(attr->values[0].unknown.data, data, (size_t)datalen);
  }

  // Return the new attribute...
  return (attr);
}


//
// 'ippAddOutOfBand()' - Add an out-of-band value to an IPP message.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "group" argument specifies the IPP attribute group tag: none
// (`IPP_TAG_ZERO`, for member attributes), document (`IPP_TAG_DOCUMENT`),
// event notification (`IPP_TAG_EVENT_NOTIFICATION`), operation
// (`IPP_TAG_OPERATION`), printer (`IPP_TAG_PRINTER`), subscription
// (`IPP_TAG_SUBSCRIPTION`), or unsupported (`IPP_TAG_UNSUPPORTED_GROUP`).
//
// Supported out-of-band values include unsupported-value
// (`IPP_TAG_UNSUPPORTED_VALUE`), default (`IPP_TAG_DEFAULT`), unknown
// (`IPP_TAG_UNKNOWN`), no-value (`IPP_TAG_NOVALUE`), not-settable
// (`IPP_TAG_NOTSETTABLE`), delete-attribute (`IPP_TAG_DELETEATTR`), and
// admin-define (`IPP_TAG_ADMINDEFINE`).
//

ipp_attribute_t	*			// O - New attribute
ippAddOutOfBand(ipp_t      *ipp,	// I - IPP message
                ipp_tag_t  group,	// I - IPP group
                ipp_tag_t  value_tag,	// I - Type of attribute
		const char *name)	// I - Name of attribute
{
  DEBUG_printf("ippAddOutOfBand(ipp=%p, group=%02x(%s), value_tag=%02x(%s), name=\"%s\")", (void *)ipp, group, ippTagString(group), value_tag, ippTagString(value_tag), name);

  value_tag &= IPP_TAG_CUPS_MASK;

  // Range check input...
  if (!ipp || !name || group < IPP_TAG_ZERO || group == IPP_TAG_END || group >= IPP_TAG_UNSUPPORTED_VALUE || (value_tag != IPP_TAG_UNSUPPORTED_VALUE && value_tag != IPP_TAG_DEFAULT && value_tag != IPP_TAG_UNKNOWN && value_tag != IPP_TAG_NOVALUE && value_tag != IPP_TAG_NOTSETTABLE && value_tag != IPP_TAG_DELETEATTR && value_tag != IPP_TAG_ADMINDEFINE))
    return (NULL);

  // Create the attribute...
  return (ipp_add_attr(ipp, name, group, value_tag, 1));
}


//
// 'ippAddRange()' - Add a range of values to an IPP message.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "group" argument specifies the IPP attribute group tag: none
// (`IPP_TAG_ZERO`, for member attributes), document (`IPP_TAG_DOCUMENT`),
// event notification (`IPP_TAG_EVENT_NOTIFICATION`), operation
// (`IPP_TAG_OPERATION`), printer (`IPP_TAG_PRINTER`), subscription
// (`IPP_TAG_SUBSCRIPTION`), or unsupported (`IPP_TAG_UNSUPPORTED_GROUP`).
//
// The "lower" argument must be less than or equal to the `upper" argument.
//

ipp_attribute_t *			// O - New attribute
ippAddRange(ipp_t      *ipp,		// I - IPP message
            ipp_tag_t  group,		// I - IPP group
	    const char *name,		// I - Name of attribute
	    int        lower,		// I - Lower value
	    int        upper)		// I - Upper value
{
  ipp_attribute_t	*attr;		// New attribute


  DEBUG_printf("ippAddRange(ipp=%p, group=%02x(%s), name=\"%s\", lower=%d, upper=%d)", (void *)ipp, group, ippTagString(group), name, lower, upper);

  // Range check input...
  if (!ipp || !name || group < IPP_TAG_ZERO || group == IPP_TAG_END || group >= IPP_TAG_UNSUPPORTED_VALUE)
    return (NULL);

  // Create the attribute...
  if ((attr = ipp_add_attr(ipp, name, group, IPP_TAG_RANGE, 1)) == NULL)
    return (NULL);

  attr->values[0].range.lower = lower;
  attr->values[0].range.upper = upper;

  return (attr);
}


//
// 'ippAddRanges()' - Add ranges of values to an IPP message.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "group" argument specifies the IPP attribute group tag: none
// (`IPP_TAG_ZERO`, for member attributes), document (`IPP_TAG_DOCUMENT`),
// event notification (`IPP_TAG_EVENT_NOTIFICATION`), operation
// (`IPP_TAG_OPERATION`), printer (`IPP_TAG_PRINTER`), subscription
// (`IPP_TAG_SUBSCRIPTION`), or unsupported (`IPP_TAG_UNSUPPORTED_GROUP`).
//

ipp_attribute_t *			// O - New attribute
ippAddRanges(ipp_t      *ipp,		// I - IPP message
             ipp_tag_t  group,		// I - IPP group
	     const char *name,		// I - Name of attribute
	     size_t     num_values,	// I - Number of values
	     const int  *lower,		// I - Lower values
	     const int  *upper)		// I - Upper values
{
  size_t		i;		// Looping var
  ipp_attribute_t	*attr;		// New attribute
  _ipp_value_t		*value;		// Current value


  DEBUG_printf("ippAddRanges(ipp=%p, group=%02x(%s), name=\"%s\", num_values=%u, lower=%p, upper=%p)", (void *)ipp, group, ippTagString(group), name, (unsigned)num_values, (void *)lower, (void *)upper);

  // Range check input...
  if (!ipp || !name || group < IPP_TAG_ZERO || group == IPP_TAG_END || group >= IPP_TAG_UNSUPPORTED_VALUE || num_values < 1)
    return (NULL);

  // Create the attribute...
  if ((attr = ipp_add_attr(ipp, name, group, IPP_TAG_RANGE, num_values)) == NULL)
    return (NULL);

  if (lower && upper)
  {
    for (i = num_values, value = attr->values; i > 0; i --, value ++)
    {
      value->range.lower = *lower++;
      value->range.upper = *upper++;
    }
  }

  return (attr);
}


//
// 'ippAddResolution()' - Add a resolution value to an IPP message.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "group" argument specifies the IPP attribute group tag: none
// (`IPP_TAG_ZERO`, for member attributes), document (`IPP_TAG_DOCUMENT`),
// event notification (`IPP_TAG_EVENT_NOTIFICATION`), operation
// (`IPP_TAG_OPERATION`), printer (`IPP_TAG_PRINTER`), subscription
// (`IPP_TAG_SUBSCRIPTION`), or unsupported (`IPP_TAG_UNSUPPORTED_GROUP`).
//

ipp_attribute_t *			// O - New attribute
ippAddResolution(ipp_t      *ipp,	// I - IPP message
        	 ipp_tag_t  group,	// I - IPP group
		 const char *name,	// I - Name of attribute
		 ipp_res_t  units,	// I - Units for resolution
		 int        xres,	// I - X resolution
		 int        yres)	// I - Y resolution
{
  ipp_attribute_t	*attr;		// New attribute


  DEBUG_printf("ippAddResolution(ipp=%p, group=%02x(%s), name=\"%s\", units=%d, xres=%d, yres=%d)", (void *)ipp, group, ippTagString(group), name, units, xres, yres);

  // Range check input...
  if (!ipp || !name || group < IPP_TAG_ZERO || group == IPP_TAG_END || group >= IPP_TAG_UNSUPPORTED_VALUE || units < IPP_RES_PER_INCH || units > IPP_RES_PER_CM || xres < 0 || yres < 0)
    return (NULL);

  // Create the attribute...
  if ((attr = ipp_add_attr(ipp, name, group, IPP_TAG_RESOLUTION, 1)) == NULL)
    return (NULL);

  attr->values[0].resolution.xres  = xres;
  attr->values[0].resolution.yres  = yres;
  attr->values[0].resolution.units = units;

  return (attr);
}


//
// 'ippAddResolutions()' - Add resolution values to an IPP message.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "group" argument specifies the IPP attribute group tag: none
// (`IPP_TAG_ZERO`, for member attributes), document (`IPP_TAG_DOCUMENT`),
// event notification (`IPP_TAG_EVENT_NOTIFICATION`), operation
// (`IPP_TAG_OPERATION`), printer (`IPP_TAG_PRINTER`), subscription
// (`IPP_TAG_SUBSCRIPTION`), or unsupported (`IPP_TAG_UNSUPPORTED_GROUP`).
//

ipp_attribute_t *			// O - New attribute
ippAddResolutions(ipp_t      *ipp,	// I - IPP message
        	  ipp_tag_t  group,	// I - IPP group
		  const char *name,	// I - Name of attribute
		  size_t     num_values,// I - Number of values
		  ipp_res_t  units,	// I - Units for resolution
		  const int  *xres,	// I - X resolutions
		  const int  *yres)	// I - Y resolutions
{
  size_t		i;		// Looping var
  ipp_attribute_t	*attr;		// New attribute
  _ipp_value_t		*value;		// Current value


  DEBUG_printf("ippAddResolutions(ipp=%p, group=%02x(%s), name=\"%s\", num_value=%u, units=%d, xres=%p, yres=%p)", (void *)ipp, group, ippTagString(group), name, (unsigned)num_values, units, (void *)xres, (void *)yres);

  // Range check input...
  if (!ipp || !name || group < IPP_TAG_ZERO || group == IPP_TAG_END || group >= IPP_TAG_UNSUPPORTED_VALUE || num_values < 1 || units < IPP_RES_PER_INCH || units > IPP_RES_PER_CM)
    return (NULL);

  // Create the attribute...
  if ((attr = ipp_add_attr(ipp, name, group, IPP_TAG_RESOLUTION, num_values)) == NULL)
    return (NULL);

  if (xres && yres)
  {
    for (i = num_values, value = attr->values; i > 0; i --, value ++)
    {
      value->resolution.xres  = *xres++;
      value->resolution.yres  = *yres++;
      value->resolution.units = units;
    }
  }

  return (attr);
}


//
// 'ippAddSeparator()' - Add a group separator to an IPP message.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//

ipp_attribute_t *			// O - New attribute
ippAddSeparator(ipp_t *ipp)		// I - IPP message
{
  DEBUG_printf("ippAddSeparator(ipp=%p)", (void *)ipp);

  // Range check input...
  if (!ipp)
    return (NULL);

  // Create the attribute...
  return (ipp_add_attr(ipp, NULL, IPP_TAG_ZERO, IPP_TAG_ZERO, 0));
}


//
// 'ippAddString()' - Add a language-encoded string to an IPP message.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "group" argument specifies the IPP attribute group tag: none
// (`IPP_TAG_ZERO`, for member attributes), document (`IPP_TAG_DOCUMENT`),
// event notification (`IPP_TAG_EVENT_NOTIFICATION`), operation
// (`IPP_TAG_OPERATION`), printer (`IPP_TAG_PRINTER`), subscription
// (`IPP_TAG_SUBSCRIPTION`), or unsupported (`IPP_TAG_UNSUPPORTED_GROUP`).
//
// Supported string values include charset (`IPP_TAG_CHARSET`), keyword
// (`IPP_TAG_KEYWORD`), language (`IPP_TAG_LANGUAGE`), mimeMediaType
// (`IPP_TAG_MIMETYPE`), name (`IPP_TAG_NAME`), nameWithLanguage
// (@code IPP_TAG_NAMELANG), text (`IPP_TAG_TEXT`), textWithLanguage
// (`IPP_TAG_TEXTLANG`), uri (`IPP_TAG_URI`), and uriScheme
// (`IPP_TAG_URISCHEME`).
//
// The "language" argument must be non-`NULL` for nameWithLanguage and
// textWithLanguage string values and must be `NULL` for all other string values.
//

ipp_attribute_t *			// O - New attribute
ippAddString(ipp_t      *ipp,		// I - IPP message
             ipp_tag_t  group,		// I - IPP group
	     ipp_tag_t  value_tag,	// I - Type of attribute
             const char *name,		// I - Name of attribute
             const char *language,	// I - Language code
             const char *value)		// I - Value
{
  ipp_tag_t		temp_tag;	// Temporary value tag (masked)
  ipp_attribute_t	*attr;		// New attribute
  char			code[IPP_MAX_LANGUAGE];
					// Charset/language code buffer


  DEBUG_printf("ippAddString(ipp=%p, group=%02x(%s), value_tag=%02x(%s), name=\"%s\", language=\"%s\", value=\"%s\")", (void *)ipp, group, ippTagString(group), value_tag, ippTagString(value_tag), name, language, value);

  // Range check input...
  temp_tag = (ipp_tag_t)((int)value_tag & IPP_TAG_CUPS_MASK);

#if 0
  if (!ipp || !name || group < IPP_TAG_ZERO ||
      group == IPP_TAG_END || group >= IPP_TAG_UNSUPPORTED_VALUE ||
      (temp_tag < IPP_TAG_TEXT && temp_tag != IPP_TAG_TEXTLANG &&
       temp_tag != IPP_TAG_NAMELANG) || temp_tag > IPP_TAG_MIMETYPE)
    return (NULL);

  if ((temp_tag == IPP_TAG_TEXTLANG || temp_tag == IPP_TAG_NAMELANG)
          != (language != NULL))
    return (NULL);
#else
  if (!ipp || !name || group < IPP_TAG_ZERO || group == IPP_TAG_END || group >= IPP_TAG_UNSUPPORTED_VALUE)
    return (NULL);
#endif // 0

  // See if we need to map charset, language, or locale values...
  if (language && ((int)value_tag & IPP_TAG_CUPS_CONST) && strcmp(language, ipp_lang_code(language, code, sizeof(code))))
    value_tag = temp_tag;		// Don't do a fast copy
  else if (value && value_tag == (ipp_tag_t)(IPP_TAG_CHARSET | IPP_TAG_CUPS_CONST) && strcmp(value, ipp_get_code(value, code, sizeof(code))))
    value_tag = temp_tag;		// Don't do a fast copy
  else if (value && value_tag == (ipp_tag_t)(IPP_TAG_LANGUAGE | IPP_TAG_CUPS_CONST) && strcmp(value, ipp_lang_code(value, code, sizeof(code))))
    value_tag = temp_tag;		// Don't do a fast copy

  // Create the attribute...
  if ((attr = ipp_add_attr(ipp, name, group, value_tag, 1)) == NULL)
    return (NULL);

  // Initialize the attribute data...
  if ((int)value_tag & IPP_TAG_CUPS_CONST)
  {
    attr->values[0].string.language = (char *)language;
    attr->values[0].string.text     = (char *)value;
  }
  else
  {
    if (language)
      attr->values[0].string.language = _cupsStrAlloc(ipp_lang_code(language, code, sizeof(code)));

    if (value)
    {
      if (value_tag == IPP_TAG_CHARSET)
	attr->values[0].string.text = _cupsStrAlloc(ipp_get_code(value, code, sizeof(code)));
      else if (value_tag == IPP_TAG_LANGUAGE)
	attr->values[0].string.text = _cupsStrAlloc(ipp_lang_code(value, code, sizeof(code)));
      else
	attr->values[0].string.text = _cupsStrAlloc(value);
    }
  }

  return (attr);
}


//
// 'ippAddStringf()' - Add a formatted string to an IPP message.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "group" argument specifies the IPP attribute group tag: none
// (`IPP_TAG_ZERO`, for member attributes), document
// (`IPP_TAG_DOCUMENT`), event notification
// (`IPP_TAG_EVENT_NOTIFICATION`), operation (`IPP_TAG_OPERATION`),
// printer (`IPP_TAG_PRINTER`), subscription (`IPP_TAG_SUBSCRIPTION`),
// or unsupported (`IPP_TAG_UNSUPPORTED_GROUP`).
//
// Supported string values include charset (`IPP_TAG_CHARSET`), keyword
// (`IPP_TAG_KEYWORD`), language (`IPP_TAG_LANGUAGE`), mimeMediaType
// (`IPP_TAG_MIMETYPE`), name (`IPP_TAG_NAME`), nameWithLanguage
// (@code IPP_TAG_NAMELANG), text (`IPP_TAG_TEXT`), textWithLanguage
// (`IPP_TAG_TEXTLANG`), uri (`IPP_TAG_URI`), and uriScheme
// (`IPP_TAG_URISCHEME`).
//
// The "language" argument must be non-`NULL` for nameWithLanguage
// and textWithLanguage string values and must be `NULL` for all other
// string values.
//
// The "format" argument uses formatting characters compatible with the
// printf family of standard functions.  Additional arguments follow it as
// needed.  The formatted string is truncated as needed to the maximum length of
// the corresponding value type.
//

ipp_attribute_t *			// O - New attribute
ippAddStringf(ipp_t      *ipp,		// I - IPP message
              ipp_tag_t  group,		// I - IPP group
	      ipp_tag_t  value_tag,	// I - Type of attribute
	      const char *name,		// I - Name of attribute
	      const char *language,	// I - Language code (`NULL` for default)
	      const char *format,	// I - Printf-style format string
	      ...)			// I - Additional arguments as needed
{
  ipp_attribute_t	*attr;		// New attribute
  va_list		ap;		// Argument pointer


  va_start(ap, format);
  attr = ippAddStringfv(ipp, group, value_tag, name, language, format, ap);
  va_end(ap);

  return (attr);
}


//
// 'ippAddStringfv()' - Add a formatted string to an IPP message.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "group" argument specifies the IPP attribute group tag: none
// (`IPP_TAG_ZERO`, for member attributes), document
// (`IPP_TAG_DOCUMENT`), event notification
// (`IPP_TAG_EVENT_NOTIFICATION`), operation (`IPP_TAG_OPERATION`),
// printer (`IPP_TAG_PRINTER`), subscription (`IPP_TAG_SUBSCRIPTION`),
// or unsupported (`IPP_TAG_UNSUPPORTED_GROUP`).
//
// Supported string values include charset (`IPP_TAG_CHARSET`), keyword
// (`IPP_TAG_KEYWORD`), language (`IPP_TAG_LANGUAGE`), mimeMediaType
// (`IPP_TAG_MIMETYPE`), name (`IPP_TAG_NAME`), nameWithLanguage
// (@code IPP_TAG_NAMELANG), text (`IPP_TAG_TEXT`), textWithLanguage
// (`IPP_TAG_TEXTLANG`), uri (`IPP_TAG_URI`), and uriScheme
// (`IPP_TAG_URISCHEME`).
//
// The "language" argument must be non-`NULL` for nameWithLanguage
// and textWithLanguage string values and must be `NULL` for all other
// string values.
//
// The "format" argument uses formatting characters compatible with the
// printf family of standard functions.  Additional arguments are passed in the
// stdarg pointer "ap".  The formatted string is truncated as needed to the
// maximum length of the corresponding value type.
//

ipp_attribute_t *			// O - New attribute
ippAddStringfv(ipp_t      *ipp,		// I - IPP message
               ipp_tag_t  group,	// I - IPP group
	       ipp_tag_t  value_tag,	// I - Type of attribute
	       const char *name,	// I - Name of attribute
	       const char *language,	// I - Language code (`NULL` for default)
	       const char *format,	// I - Printf-style format string
	       va_list    ap)		// I - Additional arguments
{
  char		buffer[IPP_MAX_TEXT + 4];
					// Formatted text string
  ssize_t	bytes,			// Length of formatted value
		max_bytes;		// Maximum number of bytes for value


  // Range check input...
  if (!ipp || !name || group < IPP_TAG_ZERO || group == IPP_TAG_END || group >= IPP_TAG_UNSUPPORTED_VALUE || (value_tag < IPP_TAG_TEXT && value_tag != IPP_TAG_TEXTLANG && value_tag != IPP_TAG_NAMELANG) || value_tag > IPP_TAG_MIMETYPE || !format)
    return (NULL);

  if ((value_tag == IPP_TAG_TEXTLANG || value_tag == IPP_TAG_NAMELANG) != (language != NULL))
    return (NULL);

  // Format the string...
  if (!strcmp(format, "%s"))
  {
    // Optimize the simple case...
    const char *s = va_arg(ap, char *);

    if (!s)
      s = "(null)";

    bytes = (ssize_t)strlen(s);
    cupsCopyString(buffer, s, sizeof(buffer));
  }
  else
  {
    // Do a full formatting of the message...
    if ((bytes = vsnprintf(buffer, sizeof(buffer), format, ap)) < 0)
      return (NULL);
  }

  // Limit the length of the string...
  switch (value_tag)
  {
    default :
    case IPP_TAG_TEXT :
    case IPP_TAG_TEXTLANG :
        max_bytes = IPP_MAX_TEXT;
        break;

    case IPP_TAG_NAME :
    case IPP_TAG_NAMELANG :
        max_bytes = IPP_MAX_NAME;
        break;

    case IPP_TAG_CHARSET :
        max_bytes = IPP_MAX_CHARSET;
        break;

    case IPP_TAG_KEYWORD :
        max_bytes = IPP_MAX_KEYWORD;
        break;

    case IPP_TAG_LANGUAGE :
        max_bytes = IPP_MAX_LANGUAGE;
        break;

    case IPP_TAG_MIMETYPE :
        max_bytes = IPP_MAX_MIMETYPE;
        break;

    case IPP_TAG_URI :
        max_bytes = IPP_MAX_URI;
        break;

    case IPP_TAG_URISCHEME :
        max_bytes = IPP_MAX_URISCHEME;
        break;
  }

  if (bytes >= max_bytes)
  {
    // Safely truncate the UTF-8 string...
    char	*bufmax,		// Buffer at max_bytes
		*bufptr;		// Pointer into buffer

    bufptr = buffer + strlen(buffer) - 1;
    bufmax = buffer + max_bytes - 1;

    while (bufptr > bufmax)
    {
      if (*bufptr & 0x80)
      {
        while ((*bufptr & 0xc0) == 0x80 && bufptr > buffer)
          bufptr --;
      }

      if (bufptr > buffer)
        bufptr --;
    }

    *bufptr = '\0';
  }

  // Add the formatted string and return...
  return (ippAddString(ipp, group, value_tag, name, language, buffer));
}


//
// 'ippAddStrings()' - Add language-encoded strings to an IPP message.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "group" argument specifies the IPP attribute group tag: none
// (`IPP_TAG_ZERO`, for member attributes), document (`IPP_TAG_DOCUMENT`),
// event notification (`IPP_TAG_EVENT_NOTIFICATION`), operation
// (`IPP_TAG_OPERATION`), printer (`IPP_TAG_PRINTER`), subscription
// (`IPP_TAG_SUBSCRIPTION`), or unsupported (`IPP_TAG_UNSUPPORTED_GROUP`).
//
// Supported string values include charset (`IPP_TAG_CHARSET`), keyword
// (`IPP_TAG_KEYWORD`), language (`IPP_TAG_LANGUAGE`), mimeMediaType
// (`IPP_TAG_MIMETYPE`), name (`IPP_TAG_NAME`), nameWithLanguage
// (@code IPP_TAG_NAMELANG), text (`IPP_TAG_TEXT`), textWithLanguage
// (`IPP_TAG_TEXTLANG`), uri (`IPP_TAG_URI`), and uriScheme
// (`IPP_TAG_URISCHEME`).
//
// The "language" argument must be non-`NULL` for nameWithLanguage and
// textWithLanguage string values and must be `NULL` for all other string values.
//

ipp_attribute_t *			// O - New attribute
ippAddStrings(
    ipp_t              *ipp,		// I - IPP message
    ipp_tag_t          group,		// I - IPP group
    ipp_tag_t          value_tag,	// I - Type of attribute
    const char         *name,		// I - Name of attribute
    size_t             num_values,	// I - Number of values
    const char         *language,	// I - Language code (`NULL` for default)
    const char * const *values)		// I - Values
{
  size_t		i;		// Looping var
  ipp_tag_t		temp_tag;	// Temporary value tag (masked)
  ipp_attribute_t	*attr;		// New attribute
  _ipp_value_t		*value;		// Current value
  char			code[32];	// Language/charset value buffer


  DEBUG_printf("ippAddStrings(ipp=%p, group=%02x(%s), value_tag=%02x(%s), name=\"%s\", num_values=%u, language=\"%s\", values=%p)", (void *)ipp, group, ippTagString(group), value_tag, ippTagString(value_tag), name, (unsigned)num_values, language, (void *)values);

  // Range check input...
  temp_tag = (ipp_tag_t)((int)value_tag & IPP_TAG_CUPS_MASK);

#if 0
  if (!ipp || !name || group < IPP_TAG_ZERO || group == IPP_TAG_END || group >= IPP_TAG_UNSUPPORTED_VALUE || (temp_tag < IPP_TAG_TEXT && temp_tag != IPP_TAG_TEXTLANG && temp_tag != IPP_TAG_NAMELANG) || temp_tag > IPP_TAG_MIMETYPE || num_values < 1)
    return (NULL);

  if ((temp_tag == IPP_TAG_TEXTLANG || temp_tag == IPP_TAG_NAMELANG) != (language != NULL))
    return (NULL);
#else
  if (!ipp || !name || group < IPP_TAG_ZERO || group == IPP_TAG_END || group >= IPP_TAG_UNSUPPORTED_VALUE || num_values < 1)
    return (NULL);
#endif // 0

  // See if we need to map charset, language, or locale values...
  if (language && ((int)value_tag & IPP_TAG_CUPS_CONST) && strcmp(language, ipp_lang_code(language, code, sizeof(code))))
  {
    value_tag = temp_tag;		// Don't do a fast copy
  }
  else if (values && value_tag == (ipp_tag_t)(IPP_TAG_CHARSET | IPP_TAG_CUPS_CONST))
  {
    for (i = 0; i < num_values; i ++)
    {
      if (strcmp(values[i], ipp_get_code(values[i], code, sizeof(code))))
      {
	value_tag = temp_tag;		// Don't do a fast copy
        break;
      }
    }
  }
  else if (values && value_tag == (ipp_tag_t)(IPP_TAG_LANGUAGE | IPP_TAG_CUPS_CONST))
  {
    for (i = 0; i < num_values; i ++)
    {
      if (strcmp(values[i], ipp_lang_code(values[i], code, sizeof(code))))
      {
	value_tag = temp_tag;		// Don't do a fast copy
        break;
      }
    }
  }

  // Create the attribute...
  if ((attr = ipp_add_attr(ipp, name, group, value_tag, num_values)) == NULL)
    return (NULL);

  // Initialize the attribute data...
  for (i = num_values, value = attr->values; i > 0; i --, value ++)
  {
    if (language)
    {
      if (value == attr->values)
      {
        if ((int)value_tag & IPP_TAG_CUPS_CONST)
          value->string.language = (char *)language;
        else
          value->string.language = _cupsStrAlloc(ipp_lang_code(language, code, sizeof(code)));
      }
      else
      {
	value->string.language = attr->values[0].string.language;
      }
    }

    if (values)
    {
      if ((int)value_tag & IPP_TAG_CUPS_CONST)
        value->string.text = (char *)*values++;
      else if (value_tag == IPP_TAG_CHARSET)
	value->string.text = _cupsStrAlloc(ipp_get_code(*values++, code, sizeof(code)));
      else if (value_tag == IPP_TAG_LANGUAGE)
	value->string.text = _cupsStrAlloc(ipp_lang_code(*values++, code, sizeof(code)));
      else
	value->string.text = _cupsStrAlloc(*values++);
    }
  }

  return (attr);
}


//
// 'ippContainsInteger()' - Determine whether an attribute contains the
//                          specified value or is within the list of ranges.
//
// This function returns `true` when the attribute contains either a matching
// integer or enum value, or the value falls within one of the rangeOfInteger
// values for the attribute.
//

bool					// O - `true` on a match, `false` on no match
ippContainsInteger(
    ipp_attribute_t *attr,		// I - Attribute
    int             value)		// I - Integer/enum value
{
  size_t	i;			// Looping var
  _ipp_value_t	*avalue;		// Current attribute value


  // Range check input...
  if (!attr)
    return (false);

  if (attr->value_tag != IPP_TAG_INTEGER && attr->value_tag != IPP_TAG_ENUM && attr->value_tag != IPP_TAG_RANGE)
    return (false);

  // Compare...
  if (attr->value_tag == IPP_TAG_RANGE)
  {
    // Check ranges...
    for (i = attr->num_values, avalue = attr->values; i > 0; i --, avalue ++)
    {
      if (value >= avalue->range.lower && value <= avalue->range.upper)
        return (true);
    }
  }
  else
  {
    // Check discrete values...
    for (i = attr->num_values, avalue = attr->values; i > 0; i --, avalue ++)
    {
      if (value == avalue->integer)
        return (true);
    }
  }

  return (false);
}


//
// 'ippContainsString()' - Determine whether an attribute contains the
//                         specified string value.
//
// This function returns `true` when the attribute contains a matching charset,
// keyword, naturalLanguage, mimeMediaType, name, text, uri, or uriScheme value.
//

bool					// O - `true` on a match, `false` on no match
ippContainsString(
    ipp_attribute_t *attr,		// I - Attribute
    const char      *value)		// I - String value
{
  size_t	i;			// Looping var
  _ipp_value_t	*avalue;		// Current attribute value


  DEBUG_printf("ippContainsString(attr=%p, value=\"%s\")", (void *)attr, value);

  // Range check input...
  if (!attr || !value)
  {
    DEBUG_puts("1ippContainsString: Returning false (bad input)");
    return (false);
  }

  // Compare...
  DEBUG_printf("1ippContainsString: attr %s, %s%s with %u values.", attr->name, (attr->value_tag & IPP_TAG_CUPS_CONST) ? "(const)" : "", ippTagString(attr->value_tag), (unsigned)attr->num_values);

  switch (attr->value_tag & IPP_TAG_CUPS_MASK)
  {
    case IPP_TAG_CHARSET :
    case IPP_TAG_KEYWORD :
    case IPP_TAG_LANGUAGE :
    case IPP_TAG_URI :
    case IPP_TAG_URISCHEME :
	for (i = attr->num_values, avalue = attr->values; i > 0; i --, avalue ++)
	{
	  DEBUG_printf("1ippContainsString: value[%u]=\"%s\"", (unsigned)(attr->num_values - i), avalue->string.text);

	  if (avalue->string.text && !strcmp(value, avalue->string.text))
	  {
	    DEBUG_puts("1ippContainsString: Returning true (match)");
	    return (true);
	  }
        }
        break;

    case IPP_TAG_MIMETYPE :
    case IPP_TAG_NAME :
    case IPP_TAG_NAMELANG :
    case IPP_TAG_TEXT :
    case IPP_TAG_TEXTLANG :
	for (i = attr->num_values, avalue = attr->values; i > 0; i --, avalue ++)
	{
	  DEBUG_printf("1ippContainsString: value[%u]=\"%s\"", (unsigned)(attr->num_values - i), avalue->string.text);

	  if (avalue->string.text && !_cups_strcasecmp(value, avalue->string.text))
	  {
	    DEBUG_puts("1ippContainsString: Returning true (match)");
	    return (true);
	  }
        }
        break;

    default :
        break;
  }

  DEBUG_puts("1ippContainsString: Returning false (no match)");

  return (false);
}


//
// 'ippCopyAttribute()' - Copy an attribute.
//
// This function copies an attribute to another IPP message.  When "quickcopy"
// is `true`, a shallow reference copy of the attribute is created - this should
// only be done as long as the original source IPP message will not be freed for
// the life of the destination.
//


ipp_attribute_t *			// O - New attribute
ippCopyAttribute(
    ipp_t           *dst,		// I - Destination IPP message
    ipp_attribute_t *srcattr,		// I - Attribute to copy
    bool            quickcopy)		// I - `true` for a referenced copy, `false` for a new copy
{
  size_t		i;		// Looping var
  ipp_tag_t		srctag,		// Source value tag
			dstcopy;	// Copy bit for quick copies
  ipp_attribute_t	*dstattr;	// Destination attribute
  _ipp_value_t		*srcval,	// Source value
			*dstval;	// Destination value


  DEBUG_printf("ippCopyAttribute(dst=%p, srcattr=%p, quickcopy=%s)", (void *)dst, (void *)srcattr, quickcopy ? "true" : "false");

  // Range check input...
  if (!dst || !srcattr)
    return (NULL);

  // Copy it...
  dstcopy = (quickcopy && (srcattr->value_tag & IPP_TAG_CUPS_CONST)) ? IPP_TAG_CUPS_CONST : 0;
  srctag  = srcattr->value_tag & IPP_TAG_CUPS_MASK;

  switch (srctag)
  {
    case IPP_TAG_ZERO :
        dstattr = ippAddSeparator(dst);
	break;

    case IPP_TAG_UNSUPPORTED_VALUE :
    case IPP_TAG_DEFAULT :
    case IPP_TAG_UNKNOWN :
    case IPP_TAG_NOVALUE :
    case IPP_TAG_NOTSETTABLE :
    case IPP_TAG_DELETEATTR :
    case IPP_TAG_ADMINDEFINE :
        dstattr = ippAddOutOfBand(dst, srcattr->group_tag, srctag, srcattr->name);
        break;

    case IPP_TAG_INTEGER :
    case IPP_TAG_ENUM :
    case IPP_TAG_BOOLEAN :
    case IPP_TAG_DATE :
    case IPP_TAG_RESOLUTION :
    case IPP_TAG_RANGE :
        if ((dstattr = ipp_add_attr(dst, srcattr->name, srcattr->group_tag, srctag, srcattr->num_values)) != NULL)
	  memcpy(dstattr->values, srcattr->values, (size_t)srcattr->num_values * sizeof(_ipp_value_t));
        break;

    case IPP_TAG_TEXT :
    case IPP_TAG_NAME :
    case IPP_TAG_RESERVED_STRING :
    case IPP_TAG_KEYWORD :
    case IPP_TAG_URI :
    case IPP_TAG_URISCHEME :
    case IPP_TAG_CHARSET :
    case IPP_TAG_LANGUAGE :
    case IPP_TAG_MIMETYPE :
        if ((dstattr = ippAddStrings(dst, srcattr->group_tag, (ipp_tag_t)(srctag | dstcopy), srcattr->name, srcattr->num_values, NULL, NULL)) == NULL)
          break;

        if (dstcopy)
	{
	  // Can safely quick-copy these string values...
	  memcpy(dstattr->values, srcattr->values, (size_t)srcattr->num_values * sizeof(_ipp_value_t));
        }
	else
	{
	  // Otherwise do a normal reference counted copy...
	  for (i = srcattr->num_values, srcval = srcattr->values, dstval = dstattr->values; i > 0; i --, srcval ++, dstval ++)
	    dstval->string.text = _cupsStrAlloc(srcval->string.text);
	}
        break;

    case IPP_TAG_TEXTLANG :
    case IPP_TAG_NAMELANG :
        if ((dstattr = ippAddStrings(dst, srcattr->group_tag, (ipp_tag_t)(srctag | dstcopy), srcattr->name, srcattr->num_values, NULL, NULL)) == NULL)
          break;

        if (dstcopy)
	{
	  // Can safely quick-copy these string values...
	  memcpy(dstattr->values, srcattr->values, (size_t)srcattr->num_values * sizeof(_ipp_value_t));
        }
	else if (srcattr->value_tag & IPP_TAG_CUPS_CONST)
	{
	  // Otherwise do a normal reference counted copy...
	  for (i = srcattr->num_values, srcval = srcattr->values, dstval = dstattr->values; i > 0; i --, srcval ++, dstval ++)
	  {
	    if (srcval == srcattr->values)
              dstval->string.language = _cupsStrAlloc(srcval->string.language);
	    else
              dstval->string.language = dstattr->values[0].string.language;

	    dstval->string.text = _cupsStrAlloc(srcval->string.text);
          }
        }
        break;

    case IPP_TAG_BEGIN_COLLECTION :
        if (quickcopy)
        {
	  for (i = srcattr->num_values, srcval = srcattr->values, dstattr = NULL; i > 0; i --, srcval ++)
	  {
	    if (srcval->collection)
	    {
	      if (dstattr)
		ippSetCollection(dst, &dstattr, ippGetCount(dstattr), srcval->collection);
	      else
		dstattr = ippAddCollection(dst, srcattr->group_tag, srcattr->name, srcval->collection);
	    }
	  }
	}
	else
	{
	  for (i = srcattr->num_values, srcval = srcattr->values, dstattr = NULL; i > 0; i --, srcval ++)
	  {
	    if (srcval->collection)
	    {
	      ipp_t *col = ippNew();	// Copy of collection

              if (!col)
              {
                ippDeleteAttribute(dst, dstattr);
                return (NULL);
              }

	      ippCopyAttributes(col, srcval->collection, false, /*cb*/NULL, /*cb_data*/NULL);

	      if (dstattr)
		ippSetCollection(dst, &dstattr, ippGetCount(dstattr), col);
	      else
		dstattr = ippAddCollection(dst, srcattr->group_tag, srcattr->name, col);

              col->use --;
	    }
	  }
	}
        break;

    case IPP_TAG_STRING :
    default :
        if ((dstattr = ipp_add_attr(dst, srcattr->name, srcattr->group_tag, srctag, srcattr->num_values)) == NULL)
          break;

        for (i = srcattr->num_values, srcval = srcattr->values, dstval = dstattr->values; i > 0; i --, srcval ++, dstval ++)
	{
	  dstval->unknown.length = srcval->unknown.length;

	  if (dstval->unknown.length > 0)
	  {
	    if ((dstval->unknown.data = malloc((size_t)dstval->unknown.length)) == NULL)
	      dstval->unknown.length = 0;
	    else
	      memcpy(dstval->unknown.data, srcval->unknown.data, (size_t)dstval->unknown.length);
	  }
	}
        break; // anti-compiler-warning-code
  }

  return (dstattr);
}


//
// 'ippCopyAttributes()' - Copy attributes from one IPP message to another.
//
// This function copies zero or more attributes from the source to the
// destination IPP message.  When "quickcopy" is `true`, a shallow reference
// copy of the attribute is created - this should only be done as long as the
// original source IPP message will not be freed for the life of the
// destination.
//
// The "cb" and "cb_data" arguments provide a generic way to "filter" the
// attributes that are copied - the function must return `true` to copy the
// attribute or `false` to skip it.  The function may also choose to do a
// partial copy of the source attribute itself and return `false` to tell this
// function to skip it.
//

bool					// O - `true` on success, `false` on error
ippCopyAttributes(
    ipp_t         *dst,			// I - Destination IPP message
    ipp_t         *src,			// I - Source IPP message
    bool          quickcopy,		// I - `true` for a referenced copy, `false` for a new copy
    ipp_copy_cb_t cb,			// I - Copy callback or `NULL` for none
    void          *cb_data)		// I - Callback data pointer
{
  ipp_attribute_t	*srcattr;	// Source attribute


  DEBUG_printf("ippCopyAttributes(dst=%p, src=%p, quickcopy=%s, cb=%p, cb_data=%p)", (void *)dst, (void *)src, quickcopy ? "true" : "false", (void *)cb, cb_data);

  // Range check input...
  if (!dst || !src)
    return (false);

  // Loop through source attributes and copy as needed...
  for (srcattr = src->attrs; srcattr; srcattr = srcattr->next)
  {
    if (!cb || (*cb)(cb_data, dst, srcattr))
    {
      if (!ippCopyAttribute(dst, srcattr, quickcopy))
        return (false);
    }
  }

  return (true);
}


//
// 'ippCopyCredentialsString()' - Copy a credentials value from an IPP attribute.
//
// This function concatenates the 1setOf text credential values of an attribute,
// separated by newlines.  The returned string must be freed using the `free`
// function.
//

char *					// O - Combined string or `NULL` on error
ippCopyCredentialsString(
    ipp_attribute_t *attr)		// I - Attribute
{
  char		*s = NULL,		// Combined string
		*ptr;			// Pointer into string
  size_t	i,			// Looping var
		slen;			// Length of combined string


  if (attr && ippGetValueTag(attr) == IPP_TAG_TEXT)
  {
    // Loop through string values and add up the total length...
    for (i = 0, slen = 0; i < attr->num_values; i ++)
    {
      if (attr->values[i].string.text)
        slen += strlen(attr->values[i].string.text) + 1;
    }

    if (slen > 0)
    {
      // Allocate memory...
      if ((s = malloc(slen + 1)) != NULL)
      {
	for (i = 0, ptr = s; i < attr->num_values; i ++)
	{
	  if (attr->values[i].string.text)
	  {
	    size_t len = strlen(attr->values[i].string.text);
					  // Length of string

	    memcpy(ptr, attr->values[i].string.text, len);
	    ptr += len;
	    *ptr++ = '\n';
	  }
	}

	*ptr = '\0';
      }
    }
  }

  return (s);
}


//
// 'ippDateToTime()' - Convert from RFC 2579 Date/Time format to time in
//                     seconds.
//

time_t					// O - UNIX time value
ippDateToTime(const ipp_uchar_t *date)	// I - RFC 2579 date info
{
  struct tm	unixdate;		// UNIX date/time info
  time_t	t;			// Computed time


  if (!date)
    return (0);

  memset(&unixdate, 0, sizeof(unixdate));

  // RFC-2579 date/time format is:
  //
  //    Byte(s)  Description
  //    -------  -----------
  //    0-1      Year (0 to 65535)
  //    2        Month (1 to 12)
  //    3        Day (1 to 31)
  //    4        Hours (0 to 23)
  //    5        Minutes (0 to 59)
  //    6        Seconds (0 to 60, 60 = "leap second")
  //    7        Deciseconds (0 to 9)
  //    8        +/- UTC
  //    9        UTC hours (0 to 14)
  //    10       UTC minutes (0 to 59)
  unixdate.tm_year = ((date[0] << 8) | date[1]) - 1900;
  unixdate.tm_mon  = date[2] - 1;
  unixdate.tm_mday = date[3];
  unixdate.tm_hour = date[4];
  unixdate.tm_min  = date[5];
  unixdate.tm_sec  = date[6];

#if _WIN32
  if ((t = _mkgmtime(&unixdate)) < 0)
    return (0);

#elif defined(HAVE_TIMEGM)
  if ((t = timegm(&unixdate)) < 0)
    return (0);

#else
  if ((t = mktime(&unixdate)) < 0)
    return (0);

#  if defined(HAVE_TM_GMTOFF)
  // Adjust the time value using the "tm_gmtoff" and "tm_isdst" members.  As
  // noted by M-HT on Github, this DST hack will fail in timezones where the
  // DST offset is not one hour, such as Australia/Lord_Howe.  Fortunately,
  // this is unusual and most systems support the "timegm" function...
  t += unixdate.tm_gmtoff - 3600 * unixdate.tm_isdst;
#  else
  // Adjust the time value using the even more legacy "timezone" variable,
  // which also reflects any DST offset...
  t += timezone;
#  endif // HAVE_TM_GMTOFF
#endif // _WIN32

  // Subtract the UTC timezone offset to get the actual time_t value...
  if (date[8] == '-')
    t += date[9] * 3600 + date[10] * 60;// "t - -offset" is "t + offset"
  else
    t -= date[9] * 3600 + date[10] * 60;// "t - offset"

  return (t);
}


//
// 'ippDelete()' - Delete an IPP message.
//

void
ippDelete(ipp_t *ipp)			// I - IPP message
{
  ipp_attribute_t	*attr,		// Current attribute
			*next;		// Next attribute


  DEBUG_printf("ippDelete(ipp=%p)", (void *)ipp);

  if (!ipp)
    return;

  ipp->use --;
  if (ipp->use > 0)
  {
    DEBUG_printf("4debug_retain: %p IPP message (use=%u)", (void *)ipp, (unsigned)ipp->use);
    return;
  }

  DEBUG_printf("4debug_free: %p IPP message", (void *)ipp);

  for (attr = ipp->attrs; attr != NULL; attr = next)
  {
    next = attr->next;

    DEBUG_printf("4debug_free: %p %s %s%s (%u values)", (void *)attr, attr->name, attr->num_values > 1 ? "1setOf " : "", ippTagString(attr->value_tag), (unsigned)attr->num_values);

    ipp_free_values(attr, 0, attr->num_values);

    if (attr->name)
      _cupsStrFree(attr->name);

    free(attr);
  }

  free(ipp);
}


//
// 'ippDeleteAttribute()' - Delete a single attribute in an IPP message.
//

void
ippDeleteAttribute(
    ipp_t           *ipp,		// I - IPP message
    ipp_attribute_t *attr)		// I - Attribute to delete
{
  ipp_attribute_t	*current,	// Current attribute
			*prev;		// Previous attribute


  DEBUG_printf("ippDeleteAttribute(ipp=%p, attr=%p(%s))", (void *)ipp, (void *)attr, attr ? attr->name : "(null)");

  // Range check input...
  if (!attr)
    return;

  DEBUG_printf("4debug_free: %p %s %s%s (%u values)", (void *)attr, attr->name, attr->num_values > 1 ? "1setOf " : "", ippTagString(attr->value_tag), (unsigned)attr->num_values);

  // Find the attribute in the list...
  if (ipp)
  {
    for (current = ipp->attrs, prev = NULL; current; prev = current, current = current->next)
    {
      if (current == attr)
      {
	// Found it, remove the attribute from the list...
	if (prev)
	  prev->next = current->next;
	else
	  ipp->attrs = current->next;

	if (current == ipp->last)
	  ipp->last = prev;

        break;
      }
    }

    if (!current)
      return;
  }

  // Free memory used by the attribute...
  ipp_free_values(attr, 0, attr->num_values);

  if (attr->name)
    _cupsStrFree(attr->name);

  free(attr);
}


//
// 'ippDeleteValues()' - Delete values in an attribute.
//
// This function deletes one or more values in an attribute.  The "element"
// argument specifies the first value to delete, starting at `0`.  It must be
// less than the number of values returned by @link ippGetCount@.
//
// The "attr" argument may be modified as a result of setting the value,
// which will set the variable to `NULL`.
//
// Deleting all values in an attribute deletes the attribute.
//

bool					// O  - `true` on success, `false` on failure
ippDeleteValues(
    ipp_t           *ipp,		// I  - IPP message
    ipp_attribute_t **attr,		// IO - Attribute
    size_t          element,		// I  - Index of first value to delete (`0`-based)
    size_t          count)		// I  - Number of values to delete
{
  // Range check input...
  if (!ipp || !attr || !*attr || element >= (*attr)->num_values || !count || (element + count) >= (*attr)->num_values)
    return (false);

  // If we are deleting all values, just delete the attribute entirely.
  if (count == (*attr)->num_values)
  {
    ippDeleteAttribute(ipp, *attr);
    *attr = NULL;
    return (true);
  }

  // Otherwise free the values in question and return.
  ipp_free_values(*attr, element, count);

  return (true);
}


//
// 'ippFindAttribute()' - Find a named attribute in an IPP message.
//
// This function finds the first occurrence of a named attribute in an IPP
// message.  The attribute name can contain a hierarchical list of attribute and
// member names separated by slashes, for example "media-col/media-size".
//

ipp_attribute_t	*			// O - Matching attribute
ippFindAttribute(ipp_t      *ipp,	// I - IPP message
                 const char *name,	// I - Name of attribute
		 ipp_tag_t  type)	// I - Type of attribute
{
  DEBUG_printf("2ippFindAttribute(ipp=%p, name=\"%s\", type=%02x(%s))", (void *)ipp, name, type, ippTagString(type));

  // Range check input...
  if (!ipp || !name)
    return (NULL);

  // Reset the current attribute pointer...
  ipp->find->attr  = NULL;
  ipp->find->idx   = 0;
  ipp->find->atend = false;

  // Search for the attribute...
  return (ippFindNextAttribute(ipp, name, type));
}


//
// 'ippFindNextAttribute()' - Find the next named attribute in an IPP message.
//
// This function finds the next named attribute in an IPP message.  The
// attribute name can contain a hierarchical list of attribute and member names
// separated by slashes, for example "media-col/media-size".
//

ipp_attribute_t	*			// O - Matching attribute
ippFindNextAttribute(ipp_t      *ipp,	// I - IPP message
                     const char *name,	// I - Name of attribute
		     ipp_tag_t  type)	// I - Type of attribute
{
  ipp_attribute_t	*attr,		// Current attribute
			*childattr;	// Child attribute
  ipp_tag_t		value_tag;	// Value tag
  char			parent[1024],	// Parent attribute name
			*child = NULL;	// Child attribute name


  DEBUG_printf("2ippFindNextAttribute(ipp=%p, name=\"%s\", type=%02x(%s))", (void *)ipp, name, type, ippTagString(type));

  // Range check input...
  if (!ipp || !name)
    return (NULL);

  DEBUG_printf("3ippFindNextAttribute: atend=%s", ipp->find->atend ? "true" : "false");

  if (ipp->find->atend)
    return (NULL);

  if (strchr(name, '/'))
  {
    // Search for child attribute...
    cupsCopyString(parent, name, sizeof(parent));
    if ((child = strchr(parent, '/')) == NULL)
    {
      DEBUG_puts("3ippFindNextAttribute: Attribute name too long.");
      return (NULL);
    }

    *child++ = '\0';

    if (ipp->find->attr && ipp->find->attr->name && ipp->find->attr->value_tag == IPP_TAG_BEGIN_COLLECTION && !strcmp(parent, ipp->find->attr->name))
    {
      while (ipp->find->idx < ipp->find->attr->num_values)
      {
        if ((childattr = ippFindNextAttribute(ipp->find->attr->values[ipp->find->idx].collection, child, type)) != NULL)
          return (childattr);

        ipp->find->idx ++;
        if (ipp->find->idx < ipp->find->attr->num_values && ipp->find->attr->values[ipp->find->idx].collection)
          ipp->find->attr->values[ipp->find->idx].collection->find->attr = NULL;
      }

      ipp->find->attr = ipp->find->attr->next;
      ipp->find->idx  = 0;

      if (!ipp->find->attr)
      {
        ipp->find->atend = true;
        return (NULL);
      }
    }

    if (!ipp->find->attr)
    {
      ipp->find->attr = ipp->attrs;
      ipp->find->idx  = 0;
    }

    name = parent;
    attr = ipp->find->attr;
  }
  else if (ipp->find->attr)
  {
    attr = ipp->find->attr->next;
  }
  else
  {
    attr = ipp->attrs;
  }

  for (; attr != NULL; ipp->prev = attr, attr = attr->next)
  {
    DEBUG_printf("4ippFindAttribute: attr=%p, name=\"%s\"", (void *)attr, attr->name);

    value_tag = (ipp_tag_t)(attr->value_tag & IPP_TAG_CUPS_MASK);

    if (attr->name != NULL && strcmp(attr->name, name) == 0 && (value_tag == type || type == IPP_TAG_ZERO || name == parent || (value_tag == IPP_TAG_TEXTLANG && type == IPP_TAG_TEXT) || (value_tag == IPP_TAG_NAMELANG && type == IPP_TAG_NAME)))
    {
      ipp->find->attr = attr;

      if (name == parent && attr->value_tag == IPP_TAG_BEGIN_COLLECTION)
      {
        size_t i;			// Looping var

        for (i = 0; i < attr->num_values; i ++)
        {
	  if ((childattr = ippFindAttribute(attr->values[i].collection, child, type)) != NULL)
	  {
	    attr->values[0].collection->find->idx = i;
	    return (childattr);
	  }
        }
      }
      else
      {
        return (attr);
      }
    }
  }

  // If we get this far, we didn't find it...
  ipp->find->attr  = NULL;
  ipp->find->atend = true;

  return (NULL);
}


//
// 'ippGetBoolean()' - Get a boolean value for an attribute.
//
// The "element" argument specifies which value to get from `0` to
// `ippGetCount(attr) - 1`.
//

bool					// O - Boolean value or `false` on error
ippGetBoolean(ipp_attribute_t *attr,	// I - IPP attribute
              size_t          element)	// I - Value number (`0`-based)
{
  // Range check input...
  if (!attr || attr->value_tag != IPP_TAG_BOOLEAN || element >= attr->num_values)
    return (false);

  // Return the value...
  return (attr->values[element].boolean);
}


//
// 'ippGetCollection()' - Get a collection value for an attribute.
//
// The "element" argument specifies which value to get from `0` to
// `ippGetCount(attr) - 1`.
//

ipp_t *					// O - Collection value or `NULL` on error
ippGetCollection(
    ipp_attribute_t *attr,		// I - IPP attribute
    size_t          element)		// I - Value number (`0`-based)
{
  // Range check input...
  if (!attr || attr->value_tag != IPP_TAG_BEGIN_COLLECTION || element >= attr->num_values)
    return (NULL);

  // Return the value...
  return (attr->values[element].collection);
}


//
// 'ippGetCount()' - Get the number of values in an attribute.
//

size_t					// O - Number of values or 0 on error
ippGetCount(ipp_attribute_t *attr)	// I - IPP attribute
{
  // Range check input...
  if (!attr)
    return (0);

  // Return the number of values...
  return (attr->num_values);
}


//
// 'ippGetDate()' - Get a dateTime value for an attribute.
//
// The "element" argument specifies which value to get from `0` to
// `ippGetCount(attr) - 1`.
//

const ipp_uchar_t *			// O - dateTime value or `NULL`
ippGetDate(ipp_attribute_t *attr,	// I - IPP attribute
           size_t          element)	// I - Value number (`0`-based)
{
  // Range check input...
  if (!attr || attr->value_tag != IPP_TAG_DATE || element >= attr->num_values)
    return (NULL);

  // Return the value...
  return (attr->values[element].date);
}


//
// 'ippGetFirstAttribute()' - Return the first attribute in the message.
//

ipp_attribute_t	*			// O - First attribute or `NULL` if none
ippGetFirstAttribute(ipp_t *ipp)	// I - IPP message
{
  // Range check input...
  if (!ipp)
    return (NULL);

  if (!ipp->find)
    ipp->find = ipp->fstack;

  ipp->find->attr  = ipp->attrs;
  ipp->find->idx   = 0;
  ipp->find->atend = ipp->find->attr == NULL;

  // Return the first attribute...
  return (ipp->find->attr);
}


//
// 'ippGetGroupTag()' - Get the group associated with an attribute.
//

ipp_tag_t				// O - Group tag or `IPP_TAG_ZERO` on error
ippGetGroupTag(ipp_attribute_t *attr)	// I - IPP attribute
{
  // Range check input...
  if (!attr)
    return (IPP_TAG_ZERO);

  // Return the group...
  return (attr->group_tag);
}


//
// 'ippGetInteger()' - Get the integer/enum value for an attribute.
//
// The "element" argument specifies which value to get from `0` to
// `ippGetCount(attr) - 1`.
//

int					// O - Value or `0` on error
ippGetInteger(ipp_attribute_t *attr,	// I - IPP attribute
              size_t          element)	// I - Value number (`0`-based)
{
  // Range check input...
  if (!attr || (attr->value_tag != IPP_TAG_INTEGER && attr->value_tag != IPP_TAG_ENUM) || element >= attr->num_values)
    return (0);

  // Return the value...
  return (attr->values[element].integer);
}


//
// 'ippGetLength()' - Compute the length of an IPP message.
//

size_t					// O - Size of IPP message
ippGetLength(ipp_t *ipp)		// I - IPP message
{
  return (ipp_length(ipp, 0));
}


//
// 'ippGetName()' - Get the attribute name.
//

const char *				// O - Attribute name or `NULL` for separators
ippGetName(ipp_attribute_t *attr)	// I - IPP attribute
{
  // Range check input...
  if (!attr)
    return (NULL);

  // Return the name...
  return (attr->name);
}


//
// 'ippGetNextAttribute()' - Return the next attribute in the message.
//

ipp_attribute_t *			// O - Next attribute or `NULL` if none
ippGetNextAttribute(ipp_t *ipp)		// I - IPP message
{
  // Range check input...
  if (!ipp || !ipp->find || !ipp->find->attr)
    return (NULL);

  ipp->find->attr  = ipp->find->attr->next;
  ipp->find->atend = ipp->find->attr == NULL;

  // Return the next attribute...
  return (ipp->find->attr);
}


//
// 'ippGetOctetString()' - Get an octetString value from an IPP attribute.
//
// The "element" argument specifies which value to get from '0' to
// `ippGetCount(attr) - 1`.
//

void *					// O - Pointer to octetString data
ippGetOctetString(
    ipp_attribute_t *attr,		// I - IPP attribute
    size_t          element,		// I - Value number (`0`-based)
    size_t          *datalen)		// O - Length of octetString data
{
  // Range check input...
  if (!attr || (attr->value_tag != IPP_TAG_STRING && attr->value_tag != IPP_TAG_EXTENSION) || element >= attr->num_values)
  {
    if (datalen)
      *datalen = 0;

    return (NULL);
  }

  // Return the values...
  if (datalen)
    *datalen = attr->values[element].unknown.length;

  return (attr->values[element].unknown.data);
}


//
// 'ippGetOperation()' - Get the operation ID in an IPP message.
//

ipp_op_t				// O - Operation ID or 0 on error
ippGetOperation(ipp_t *ipp)		// I - IPP request message
{
  // Range check input...
  if (!ipp)
    return ((ipp_op_t)0);

  // Return the value...
  return ((ipp_op_t)ipp->request.op_status);
}


//
// 'ippGetRange()' - Get a rangeOfInteger value from an attribute.
//
// The "element" argument specifies which value to get from `0` to
// `ippGetCount(attr) - 1`.
//

int					// O - Lower value of range or 0
ippGetRange(ipp_attribute_t *attr,	// I - IPP attribute
	    size_t          element,	// I - Value number (`0`-based)
	    int             *uppervalue)// O - Upper value of range
{
  // Range check input...
  if (!attr || attr->value_tag != IPP_TAG_RANGE || element >= attr->num_values)
  {
    if (uppervalue)
      *uppervalue = 0;

    return (0);
  }

  // Return the values...
  if (uppervalue)
    *uppervalue = attr->values[element].range.upper;

  return (attr->values[element].range.lower);
}


//
// 'ippGetRequestId()' - Get the request ID from an IPP message.
//

int					// O - Request ID or 0 on error
ippGetRequestId(ipp_t *ipp)		// I - IPP message
{
  // Range check input...
  if (!ipp)
    return (0);

  // Return the request ID...
  return (ipp->request.request_id);
}


//
// 'ippGetResolution()' - Get a resolution value for an attribute.
//
// The "element" argument specifies which value to get from `0` to
// `ippGetCount(attr) - 1`.
//

int					// O - Horizontal/cross feed resolution or 0
ippGetResolution(
    ipp_attribute_t *attr,		// I - IPP attribute
    size_t          element,		// I - Value number (`0`-based)
    int             *yres,		// O - Vertical/feed resolution
    ipp_res_t       *units)		// O - Units for resolution
{
  // Range check input...
  if (!attr || attr->value_tag != IPP_TAG_RESOLUTION || element >= attr->num_values)
  {
    if (yres)
      *yres = 0;

    if (units)
      *units = (ipp_res_t)0;

    return (0);
  }

  // Return the value...
  if (yres)
    *yres = attr->values[element].resolution.yres;

  if (units)
    *units = attr->values[element].resolution.units;

  return (attr->values[element].resolution.xres);
}


//
// 'ippGetState()' - Get the IPP message state.
//

ipp_state_t				// O - IPP message state value
ippGetState(ipp_t *ipp)			// I - IPP message
{
  // Range check input...
  if (!ipp)
    return (IPP_STATE_IDLE);

  // Return the value...
  return (ipp->state);
}


//
// 'ippGetStatusCode()' - Get the status code from an IPP response or event message.
//

ipp_status_t				// O - Status code in IPP message
ippGetStatusCode(ipp_t *ipp)		// I - IPP response or event message
{
  // Range check input...
  if (!ipp)
    return (IPP_STATUS_ERROR_INTERNAL);

  // Return the value...
  return ((ipp_status_t)ipp->request.op_status);
}


//
// 'ippGetString()' - Get the string and optionally the language code for an attribute.
//
// The "element" argument specifies which value to get from `0` to
// `ippGetCount(attr) - 1`.
//

const char *
ippGetString(ipp_attribute_t *attr,	// I - IPP attribute
             size_t          element,	// I - Value number (`0`-based)
	     const char      **language)// O - Language code (`NULL` for don't care)
{
  ipp_tag_t	tag;			// Value tag


  // Range check input...
  tag = ippGetValueTag(attr);

  if (!attr || element >= attr->num_values || (tag != IPP_TAG_TEXTLANG && tag != IPP_TAG_NAMELANG && (tag < IPP_TAG_TEXT || tag > IPP_TAG_MIMETYPE)))
    return (NULL);

  // Return the value...
  if (language)
    *language = attr->values[element].string.language;

  return (attr->values[element].string.text);
}


//
// 'ippGetValueTag()' - Get the value tag for an attribute.
//

ipp_tag_t				// O - Value tag or `IPP_TAG_ZERO` on error
ippGetValueTag(ipp_attribute_t *attr)	// I - IPP attribute
{
  // Range check input...
  if (!attr)
    return (IPP_TAG_ZERO);

  // Return the value...
  return (attr->value_tag & IPP_TAG_CUPS_MASK);
}


//
// 'ippGetVersion()' - Get the major and minor version number from an IPP message.
//

int					// O - Major version number or 0 on error
ippGetVersion(ipp_t *ipp,		// I - IPP message
              int   *minor)		// O - Minor version number or `NULL` for don't care
{
  // Range check input...
  if (!ipp)
  {
    if (minor)
      *minor = 0;

    return (0);
  }

  // Return the value...
  if (minor)
    *minor = ipp->request.version[1];

  return (ipp->request.version[0]);
}


//
// 'ippNew()' - Allocate a new IPP message.
//

ipp_t *					// O - New IPP message
ippNew(void)
{
  ipp_t			*temp;		// New IPP message
  _cups_globals_t	*cg = _cupsGlobals();
					// Global data


  DEBUG_puts("ippNew()");

  if ((temp = (ipp_t *)calloc(1, sizeof(ipp_t))) != NULL)
  {
    // Set default version - usually 2.0...
    DEBUG_printf("4debug_alloc: %p IPP message", (void *)temp);

    if (!cg->client_conf_loaded)
      _cupsSetDefaults();

    temp->request.version[0] = (ipp_uchar_t)(cg->server_version / 10);
    temp->request.version[1] = (ipp_uchar_t)(cg->server_version % 10);
    temp->use                = 1;
    temp->find               = temp->fstack;
  }

  DEBUG_printf("1ippNew: Returning %p", (void *)temp);

  return (temp);
}


//
//  'ippNewRequest()' - Allocate a new IPP request message.
//
// The new request message is initialized with the "attributes-charset" and
// "attributes-natural-language" attributes added. The
// "attributes-natural-language" value is derived from the current locale.
//

ipp_t *					// O - IPP request message
ippNewRequest(ipp_op_t op)		// I - Operation code
{
  ipp_t		*request;		// IPP request message
  cups_lang_t	*language;		// Current language localization
  static int	request_id = 0;		// Current request ID
  static cups_mutex_t request_mutex = CUPS_MUTEX_INITIALIZER;
					// Mutex for request ID


  DEBUG_printf("ippNewRequest(op=%02x(%s))", op, ippOpString(op));

  // Create a new IPP message...
  if ((request = ippNew()) == NULL)
    return (NULL);

  // Set the operation and request ID...
  cupsMutexLock(&request_mutex);

  request->request.op_status  = (short)op;
  request->request.request_id = ++request_id;

  cupsMutexUnlock(&request_mutex);

  // Use UTF-8 as the character set...
  ippAddString(request, IPP_TAG_OPERATION, IPP_CONST_TAG(IPP_TAG_CHARSET), "attributes-charset", NULL, "utf-8");

  // Get the language from the current locale...
  language = cupsLangDefault();

  ippAddString(request, IPP_TAG_OPERATION, IPP_CONST_TAG(IPP_TAG_LANGUAGE), "attributes-natural-language", NULL, cupsLangGetName(language));

  // Return the new request...
  return (request);
}


//
// 'ippNewResponse()' - Allocate a new IPP response message.
//
// The new response message is initialized with the same "version-number",
// "request-id", "attributes-charset", and "attributes-natural-language" as the
// provided request message.  If the "attributes-charset" or
// "attributes-natural-language" attributes are missing from the request,
// 'utf-8' and a value derived from the current locale are substituted,
// respectively.
//

ipp_t *					// O - IPP response message
ippNewResponse(ipp_t *request)		// I - IPP request message
{
  ipp_t			*response;	// IPP response message
  ipp_attribute_t	*attr;		// Current attribute


  // Range check input...
  if (!request)
    return (NULL);

  // Create a new IPP message...
  if ((response = ippNew()) == NULL)
    return (NULL);

  // Copy the request values over to the response...
  response->request.version[0] = request->request.version[0];
  response->request.version[1] = request->request.version[1];
  response->request.request_id = request->request.request_id;

  // The first attribute MUST be attributes-charset...
  attr = request->attrs;

  if (attr && attr->name && !strcmp(attr->name, "attributes-charset") && attr->group_tag == IPP_TAG_OPERATION && attr->value_tag == IPP_TAG_CHARSET && attr->num_values == 1)
  {
    // Copy charset from request...
    ippAddString(response, IPP_TAG_OPERATION, IPP_TAG_CHARSET, "attributes-charset", NULL, attr->values[0].string.text);
  }
  else
  {
    // Use "utf-8" as the default...
    ippAddString(response, IPP_TAG_OPERATION, IPP_CONST_TAG(IPP_TAG_CHARSET), "attributes-charset", NULL, "utf-8");
  }

  // Then attributes-natural-language...
  if (attr)
    attr = attr->next;

  if (attr && attr->name && !strcmp(attr->name, "attributes-natural-language") && attr->group_tag == IPP_TAG_OPERATION && attr->value_tag == IPP_TAG_LANGUAGE && attr->num_values == 1)
  {
    // Copy language from request...
    ippAddString(response, IPP_TAG_OPERATION, IPP_TAG_LANGUAGE, "attributes-natural-language", NULL, attr->values[0].string.text);
  }
  else
  {
    // Use the language from the current locale...
    cups_lang_t *language = cupsLangDefault();
					// Current locale

    ippAddString(response, IPP_TAG_OPERATION, IPP_CONST_TAG(IPP_TAG_LANGUAGE), "attributes-natural-language", NULL, cupsLangGetName(language));
  }

  return (response);
}


//
// 'ippRead()' - Read data for an IPP message from a HTTP connection.
//

ipp_state_t				// O - Current state
ippRead(http_t *http,			// I - HTTP connection
        ipp_t  *ipp)			// I - IPP data
{
  DEBUG_printf("ippRead(http=%p, ipp=%p), data_remaining=" CUPS_LLFMT, (void *)http, (void *)ipp, CUPS_LLCAST (http ? http->data_remaining : -1));

  if (!http || !ipp)
    return (IPP_STATE_ERROR);

  DEBUG_printf("2ippRead: http->state=%d, http->used=%d", http->state, http->used);

  return (ipp_read_io(http, (ipp_io_cb_t)ipp_read_http, http->blocking, /*parent*/NULL, ipp, /*depth*/0));
}


//
// 'ippReadFile()' - Read data for an IPP message from a file.
//

ipp_state_t				// O - Current state
ippReadFile(int   fd,			// I - HTTP data
            ipp_t *ipp)			// I - IPP data
{
  DEBUG_printf("ippReadFile(fd=%d, ipp=%p)", fd, (void *)ipp);

  if (!ipp)
    return (IPP_STATE_ERROR);

  return (ipp_read_io(&fd, (ipp_io_cb_t)ipp_read_file, /*blocking*/true, /*parent*/NULL, ipp, /*depth*/0));
}


//
// 'ippReadIO()' - Read data for an IPP message.
//

ipp_state_t				// O - Current state
ippReadIO(void        *src,		// I - Data source
          ipp_io_cb_t cb,		// I - Read callback function
	  bool        blocking,		// I - Use blocking IO?
	  ipp_t       *parent,		// I - Parent request, if any
          ipp_t       *ipp)		// I - IPP data
{
  DEBUG_printf("ippReadIO(src=%p, cb=%p, blocking=%d, parent=%p, ipp=%p)", (void *)src, (void *)cb, blocking, (void *)parent, (void *)ipp);

  if (!src || !ipp)
    return (IPP_STATE_ERROR);

  return (ipp_read_io(src, cb, blocking, parent, ipp, /*depth*/0));
}


//
// 'ippRestore()' - Restore a previously saved find position.
//

void
ippRestore(ipp_t *ipp)			// I - IPP message
{
  if (ipp)
  {
    if (ipp->find > ipp->fstack)
      ipp->find --;
    else
      ipp->find = NULL;
  }
}


//
// 'ippSave()' - Save the current find position.
//

void
ippSave(ipp_t *ipp)			// I - IPP message
{
  if (ipp && ipp->find < (ipp->fstack + _IPP_MAX_FIND))
  {
    ipp->find[1] = ipp->find[0];
    ipp->find ++;
  }
}


//
// 'ippSetBoolean()' - Set a boolean value in an attribute.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "attr" argument may be modified as a result of setting the value.
//
// The "element" argument specifies which value to set from `0` to
// `ippGetCount(attr)`.
//

bool					// O  - `true` on success, `false` on failure
ippSetBoolean(ipp_t           *ipp,	// I  - IPP message
              ipp_attribute_t **attr,	// IO - IPP attribute
              size_t          element,	// I  - Value number (`0`-based)
              bool            boolvalue)// I  - Boolean value
{
  _ipp_value_t	*value;			// Current value


  // Range check input...
  if (!ipp || !attr || !*attr || (*attr)->value_tag != IPP_TAG_BOOLEAN || element > (*attr)->num_values)
    return (false);

  // Set the value and return...
  if ((value = ipp_set_value(ipp, attr, element)) != NULL)
    value->boolean = boolvalue;

  return (value != NULL);
}


//
// 'ippSetCollection()' - Set a collection value in an attribute.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "attr" argument may be modified as a result of setting the value.
//
// The "element" argument specifies which value to set from `0` to
// `ippGetCount(attr)`.
//

bool					// O  - `true` on success, `false` on failure
ippSetCollection(
    ipp_t           *ipp,		// I  - IPP message
    ipp_attribute_t **attr,		// IO - IPP attribute
    size_t          element,		// I  - Value number (`0`-based)
    ipp_t           *colvalue)		// I  - Collection value
{
  _ipp_value_t	*value;			// Current value


  // Range check input...
  if (!ipp || !attr || !*attr || (*attr)->value_tag != IPP_TAG_BEGIN_COLLECTION || element > (*attr)->num_values || !colvalue)
    return (false);

  // Set the value and return...
  if ((value = ipp_set_value(ipp, attr, element)) != NULL)
  {
    if (value->collection)
      ippDelete(value->collection);

    value->collection = colvalue;
    colvalue->use ++;
  }

  return (value != NULL);
}


//
// 'ippSetDate()' - Set a dateTime value in an attribute.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "attr" argument may be modified as a result of setting the value.
//
// The "element" argument specifies which value to set from `0` to
// `ippGetCount(attr)`.
//

bool					// O  - `true` on success, `false` on failure
ippSetDate(ipp_t             *ipp,	// I  - IPP message
           ipp_attribute_t   **attr,	// IO - IPP attribute
           size_t            element,	// I  - Value number (`0`-based)
           const ipp_uchar_t *datevalue)// I  - dateTime value
{
  _ipp_value_t	*value;			// Current value


  // Range check input...
  if (!ipp || !attr || !*attr || ((*attr)->value_tag != IPP_TAG_DATE && (*attr)->value_tag != IPP_TAG_NOVALUE && (*attr)->value_tag != IPP_TAG_UNKNOWN) || element > (*attr)->num_values || !datevalue)
    return (false);

  // Set the value and return...
  if ((value = ipp_set_value(ipp, attr, element)) != NULL)
  {
    (*attr)->value_tag = IPP_TAG_DATE;
    memcpy(value->date, datevalue, sizeof(value->date));
  }

  return (value != NULL);
}


//
// 'ippSetGroupTag()' - Set the group tag of an attribute.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "attr" argument may be modified as a result of setting the value.
//
// The "group" argument specifies the IPP attribute group tag: none
// (`IPP_TAG_ZERO`, for member attributes), document (`IPP_TAG_DOCUMENT`),
// event notification (`IPP_TAG_EVENT_NOTIFICATION`), operation
// (`IPP_TAG_OPERATION`), printer (`IPP_TAG_PRINTER`), subscription
// (`IPP_TAG_SUBSCRIPTION`), or unsupported (`IPP_TAG_UNSUPPORTED_GROUP`).
//

bool					// O  - `true` on success, `false` on failure
ippSetGroupTag(
    ipp_t           *ipp,		// I  - IPP message
    ipp_attribute_t **attr,		// IO - Attribute
    ipp_tag_t       group_tag)		// I  - Group tag
{
  // Range check input - group tag must be 0x01 to 0x0F, per RFC 8011...
  if (!ipp || !attr || !*attr || group_tag < IPP_TAG_ZERO || group_tag == IPP_TAG_END || group_tag >= IPP_TAG_UNSUPPORTED_VALUE)
    return (false);

  // Set the group tag and return...
  (*attr)->group_tag = group_tag;

  return (true);
}


//
// 'ippSetInteger()' - Set an integer or enum value in an attribute.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "attr" argument may be modified as a result of setting the value.
//
// The "element" argument specifies which value to set from `0` to
// `ippGetCount(attr)`.
//

bool					// O  - `true` on success, `false` on failure
ippSetInteger(ipp_t           *ipp,	// I  - IPP message
              ipp_attribute_t **attr,	// IO - IPP attribute
              size_t          element,	// I  - Value number (`0`-based)
              int             intvalue)	// I  - Integer/enum value
{
  _ipp_value_t	*value;			// Current value


  // Range check input...
  if (!ipp || !attr || !*attr || ((*attr)->value_tag != IPP_TAG_INTEGER && (*attr)->value_tag != IPP_TAG_ENUM && (*attr)->value_tag != IPP_TAG_NOVALUE && (*attr)->value_tag != IPP_TAG_UNKNOWN) || element > (*attr)->num_values)
    return (false);

  // Set the value and return...
  if ((value = ipp_set_value(ipp, attr, element)) != NULL)
  {
    if ((*attr)->value_tag != IPP_TAG_ENUM)
      (*attr)->value_tag = IPP_TAG_INTEGER;

    value->integer = intvalue;
  }

  return (value != NULL);
}


//
// 'ippSetName()' - Set the name of an attribute.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "attr" argument may be modified as a result of setting the value.
//

bool					// O  - `true` on success, `false` on failure
ippSetName(ipp_t           *ipp,	// I  - IPP message
	   ipp_attribute_t **attr,	// IO - IPP attribute
	   const char      *name)	// I  - Attribute name
{
  char	*temp;				// Temporary name value


  // Range check input...
  if (!ipp || !attr || !*attr || !name)
    return (false);

  // Set the value and return...
  if ((temp = _cupsStrAlloc(name)) != NULL)
  {
    if ((*attr)->name)
      _cupsStrFree((*attr)->name);

    (*attr)->name = temp;
  }

  return (temp != NULL);
}


//
// 'ippSetOctetString()' - Set an octetString value in an IPP attribute.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "attr" argument may be modified as a result of setting the value.
//
// The "element" argument specifies which value to set from `0` to
// `ippGetCount(attr)`.
//

bool					// O  - `true` on success, `false` on failure
ippSetOctetString(
    ipp_t           *ipp,		// I  - IPP message
    ipp_attribute_t **attr,		// IO - IPP attribute
    size_t          element,		// I  - Value number (`0`-based)
    const void      *data,		// I  - Pointer to octetString data
    size_t          datalen)		// I  - Length of octetString data
{
  _ipp_value_t	*value;			// Current value


  // Range check input...
  if (!ipp || !attr || !*attr || ((*attr)->value_tag != IPP_TAG_STRING && (*attr)->value_tag != IPP_TAG_NOVALUE && (*attr)->value_tag != IPP_TAG_UNKNOWN && (*attr)->value_tag != IPP_TAG_EXTENSION) || element > (*attr)->num_values || datalen > IPP_MAX_LENGTH)
    return (false);

  // Set the value and return...
  if ((value = ipp_set_value(ipp, attr, element)) != NULL)
  {
    if ((int)((*attr)->value_tag) & IPP_TAG_CUPS_CONST)
    {
      // Just copy the pointer...
      value->unknown.data   = (void *)data;
      value->unknown.length = datalen;
    }
    else
    {
      // Copy the data...
      (*attr)->value_tag = IPP_TAG_STRING;

      if (value->unknown.data)
      {
        // Free previous data...
	free(value->unknown.data);

	value->unknown.data   = NULL;
        value->unknown.length = 0;
      }

      if (datalen > 0)
      {
	void	*temp;			// Temporary data pointer

	if ((temp = malloc((size_t)datalen)) != NULL)
	{
	  memcpy(temp, data, (size_t)datalen);

	  value->unknown.data   = temp;
	  value->unknown.length = datalen;
	}
	else
	{
	  return (false);
	}
      }
    }
  }

  return (value != NULL);
}


//
// 'ippSetOperation()' - Set the operation ID in an IPP request message.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//

bool					// O  - `true` on success, `false` on failure
ippSetOperation(ipp_t    *ipp,		// I - IPP request message
                ipp_op_t op)		// I - Operation ID
{
  // Range check input...
  if (!ipp)
    return (false);

  // Set the operation and return...
  ipp->request.op_status = (short)op;

  return (true);
}


//
// 'ippSetRange()' - Set a rangeOfInteger value in an attribute.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "attr" argument may be modified as a result of setting the value.
//
// The "element" argument specifies which value to set from `0` to
// `ippGetCount(attr)`.
//

bool					// O  - `true` on success, `false` on failure
ippSetRange(ipp_t           *ipp,	// I  - IPP message
            ipp_attribute_t **attr,	// IO - IPP attribute
            size_t          element,	// I  - Value number (`0`-based)
	    int             lowervalue,	// I  - Lower bound for range
	    int             uppervalue)	// I  - Upper bound for range
{
  _ipp_value_t	*value;			// Current value


  // Range check input...
  if (!ipp || !attr || !*attr || ((*attr)->value_tag != IPP_TAG_RANGE && (*attr)->value_tag != IPP_TAG_NOVALUE && (*attr)->value_tag != IPP_TAG_UNKNOWN) || element > (*attr)->num_values || lowervalue > uppervalue)
    return (false);

  // Set the value and return...
  if ((value = ipp_set_value(ipp, attr, element)) != NULL)
  {
    (*attr)->value_tag = IPP_TAG_RANGE;
    value->range.lower = lowervalue;
    value->range.upper = uppervalue;
  }

  return (value != NULL);
}


//
// 'ippSetRequestId()' - Set the request ID in an IPP message.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "request_id" argument must be greater than 0.
//

bool					// O  - `true` on success, `false` on failure
ippSetRequestId(ipp_t *ipp,		// I - IPP message
                int   request_id)	// I - Request ID
{
  // Range check input; not checking request_id values since ipptool wants to
  // send invalid values for conformance testing and a bad request_id does not
  // affect the encoding of a message...
  if (!ipp)
    return (false);

  // Set the request ID and return...
  ipp->request.request_id = request_id;

  return (true);
}


//
// 'ippSetResolution()' - Set a resolution value in an attribute.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "attr" argument may be modified as a result of setting the value.
//
// The "element" argument specifies which value to set from `0` to
// `ippGetCount(attr)`.
//

bool					// O  - `true` on success, `false` on failure
ippSetResolution(
    ipp_t           *ipp,		// I  - IPP message
    ipp_attribute_t **attr,		// IO - IPP attribute
    size_t          element,		// I  - Value number (`0`-based)
    ipp_res_t       unitsvalue,		// I  - Resolution units
    int             xresvalue,		// I  - Horizontal/cross feed resolution
    int             yresvalue)		// I  - Vertical/feed resolution
{
  _ipp_value_t	*value;			// Current value


  // Range check input...
  if (!ipp || !attr || !*attr || ((*attr)->value_tag != IPP_TAG_RESOLUTION && (*attr)->value_tag != IPP_TAG_NOVALUE && (*attr)->value_tag != IPP_TAG_UNKNOWN) || element > (*attr)->num_values || xresvalue <= 0 || yresvalue <= 0 || unitsvalue < IPP_RES_PER_INCH || unitsvalue > IPP_RES_PER_CM)
    return (false);

  // Set the value and return...
  if ((value = ipp_set_value(ipp, attr, element)) != NULL)
  {
    (*attr)->value_tag      = IPP_TAG_RESOLUTION;
    value->resolution.units = unitsvalue;
    value->resolution.xres  = xresvalue;
    value->resolution.yres  = yresvalue;
  }

  return (value != NULL);
}


//
// 'ippSetState()' - Set the current state of the IPP message.
//

bool					// O  - `true` on success, `false` on failure
ippSetState(ipp_t       *ipp,		// I - IPP message
            ipp_state_t state)		// I - IPP state value
{
  // Range check input...
  if (!ipp)
    return (false);

  // Set the state and return...
  ipp->state   = state;
  ipp->current = NULL;

  return (true);
}


//
// 'ippSetStatusCode()' - Set the status code in an IPP response or event message.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//

bool					// O  - `true` on success, `false` on failure
ippSetStatusCode(ipp_t        *ipp,	// I - IPP response or event message
                 ipp_status_t status)	// I - Status code
{
  // Range check input...
  if (!ipp)
    return (false);

  // Set the status code and return...
  ipp->request.op_status = (short)status;

  return (true);
}


//
// 'ippSetString()' - Set a string value in an attribute.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "attr" argument may be modified as a result of setting the value.
//
// The "element" argument specifies which value to set from `0` to
// `ippGetCount(attr)`.
//

bool					// O  - `true` on success, `false` on failure
ippSetString(ipp_t           *ipp,	// I  - IPP message
             ipp_attribute_t **attr,	// IO - IPP attribute
             size_t          element,	// I  - Value number (`0`-based)
	     const char      *strvalue)	// I  - String value
{
  char		*temp;			// Temporary string
  _ipp_value_t	*value;			// Current value
  ipp_tag_t	value_tag;		// Value tag


  // Range check input...
  if (attr && *attr)
    value_tag = (*attr)->value_tag & IPP_TAG_CUPS_MASK;
  else
    value_tag = IPP_TAG_ZERO;

  if (!ipp || !attr || !*attr || (value_tag < IPP_TAG_TEXT && value_tag != IPP_TAG_TEXTLANG && value_tag != IPP_TAG_NAMELANG && value_tag != IPP_TAG_NOVALUE && value_tag != IPP_TAG_UNKNOWN) || value_tag > IPP_TAG_MIMETYPE || element > (*attr)->num_values || !strvalue)
    return (false);

  // Set the value and return...
  if ((value = ipp_set_value(ipp, attr, element)) != NULL)
  {
    if (value_tag == IPP_TAG_NOVALUE || value_tag == IPP_TAG_UNKNOWN)
      (*attr)->value_tag = IPP_TAG_KEYWORD;

    if (element > 0)
      value->string.language = (*attr)->values[0].string.language;

    if ((int)((*attr)->value_tag) & IPP_TAG_CUPS_CONST)
    {
      value->string.text = (char *)strvalue;
    }
    else if ((temp = _cupsStrAlloc(strvalue)) != NULL)
    {
      if (value->string.text)
        _cupsStrFree(value->string.text);

      value->string.text = temp;
    }
    else
    {
      return (false);
    }
  }

  return (value != NULL);
}


//
// 'ippSetStringf()' - Set a formatted string value of an attribute.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "attr" argument may be modified as a result of setting the value.
//
// The "element" argument specifies which value to set from `0` to
// `ippGetCount(attr)`.
//
// The "format" argument uses formatting characters compatible with the
// printf family of standard functions.  Additional arguments follow it as
// needed.  The formatted string is truncated as needed to the maximum length of
// the corresponding value type.
//

bool					// O  - `true` on success, `false` on failure
ippSetStringf(ipp_t           *ipp,	// I  - IPP message
              ipp_attribute_t **attr,	// IO - IPP attribute
              size_t          element,	// I  - Value number (`0`-based)
	      const char      *format,	// I  - Printf-style format string
	      ...)			// I  - Additional arguments as needed
{
  int		ret;			// Return value
  va_list	ap;			// Pointer to additional arguments


  va_start(ap, format);
  ret = ippSetStringfv(ipp, attr, element, format, ap);
  va_end(ap);

  return (ret);
}


//
// 'ippSetStringf()' - Set a formatted string value of an attribute.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "attr" argument may be modified as a result of setting the value.
//
// The "element" argument specifies which value to set from `0` to
// `ippGetCount(attr)`.
//
// The "format" argument uses formatting characters compatible with the
// printf family of standard functions.  Additional arguments follow it as
// needed.  The formatted string is truncated as needed to the maximum length of
// the corresponding value type.
//

bool					// O  - `true` on success, `false` on failure
ippSetStringfv(ipp_t           *ipp,	// I  - IPP message
               ipp_attribute_t **attr,	// IO - IPP attribute
               size_t          element,	// I  - Value number (`0`-based)
	       const char      *format,	// I  - Printf-style format string
	       va_list         ap)	// I  - Pointer to additional arguments
{
  ipp_tag_t	value_tag;		// Value tag
  char		buffer[IPP_MAX_TEXT + 4];
					// Formatted text string
  ssize_t	bytes,			// Length of formatted value
		max_bytes;		// Maximum number of bytes for value


  // Range check input...
  if (attr && *attr)
    value_tag = (*attr)->value_tag & IPP_TAG_CUPS_MASK;
  else
    value_tag = IPP_TAG_ZERO;

  if (!ipp || !attr || !*attr || (value_tag < IPP_TAG_TEXT && value_tag != IPP_TAG_TEXTLANG && value_tag != IPP_TAG_NAMELANG && value_tag != IPP_TAG_NOVALUE && value_tag != IPP_TAG_UNKNOWN) || value_tag > IPP_TAG_MIMETYPE || !format)
    return (false);

  // Format the string...
  if (!strcmp(format, "%s"))
  {
    // Optimize the simple case...
    const char *s = va_arg(ap, char *);

    if (!s)
      s = "(null)";

    bytes = (ssize_t)strlen(s);
    cupsCopyString(buffer, s, sizeof(buffer));
  }
  else
  {
    // Do a full formatting of the message...
    if ((bytes = vsnprintf(buffer, sizeof(buffer), format, ap)) < 0)
      return (0);
  }

  // Limit the length of the string...
  switch (value_tag)
  {
    default :
    case IPP_TAG_TEXT :
    case IPP_TAG_TEXTLANG :
        max_bytes = IPP_MAX_TEXT;
        break;

    case IPP_TAG_NAME :
    case IPP_TAG_NAMELANG :
        max_bytes = IPP_MAX_NAME;
        break;

    case IPP_TAG_CHARSET :
        max_bytes = IPP_MAX_CHARSET;
        break;

    case IPP_TAG_NOVALUE :
    case IPP_TAG_UNKNOWN :
    case IPP_TAG_KEYWORD :
        max_bytes = IPP_MAX_KEYWORD;
        break;

    case IPP_TAG_LANGUAGE :
        max_bytes = IPP_MAX_LANGUAGE;
        break;

    case IPP_TAG_MIMETYPE :
        max_bytes = IPP_MAX_MIMETYPE;
        break;

    case IPP_TAG_URI :
        max_bytes = IPP_MAX_URI;
        break;

    case IPP_TAG_URISCHEME :
        max_bytes = IPP_MAX_URISCHEME;
        break;
  }

  if (bytes >= max_bytes)
  {
    // Safely truncate the UTF-8 string...
    char	*bufmax,		// Buffer at max_bytes
		*bufptr;		// Pointer into buffer

    bufptr = buffer + strlen(buffer) - 1;
    bufmax = buffer + max_bytes - 1;

    while (bufptr > bufmax)
    {
      if (*bufptr & 0x80)
      {
        while ((*bufptr & 0xc0) == 0x80 && bufptr > buffer)
          bufptr --;
      }

      if (bufptr > buffer)
        bufptr --;
    }

    *bufptr = '\0';
  }

  // Set the formatted string and return...
  return (ippSetString(ipp, attr, element, _cupsStrAlloc(buffer)));
}


//
// 'ippSetValueTag()' - Set the value tag of an attribute.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "attr" argument may be modified as a result of setting the value.
//
// Integer (`IPP_TAG_INTEGER`) values can be promoted to rangeOfInteger
// (`IPP_TAG_RANGE`) values, the various string tags can be promoted to name
// (`IPP_TAG_NAME`) or nameWithLanguage (`IPP_TAG_NAMELANG`) values, text
// (`IPP_TAG_TEXT`) values can be promoted to textWithLanguage
// (`IPP_TAG_TEXTLANG`) values, and all values can be demoted to the various
// out-of-band value tags such as no-value (`IPP_TAG_NOVALUE`). All other
// changes will be rejected.
//
// Promoting a string attribute to nameWithLanguage or textWithLanguage adds the
// language code in the "attributes-natural-language" attribute or, if not
// present, the language code for the current locale.
//

bool					// O  - `true` on success, `false` on failure
ippSetValueTag(
    ipp_t          *ipp,		// I  - IPP message
    ipp_attribute_t **attr,		// IO - IPP attribute
    ipp_tag_t       value_tag)		// I  - Value tag
{
  size_t	i;			// Looping var
  _ipp_value_t	*value;			// Current value
  int		integer;		// Current integer value
  cups_lang_t	*language;		// Current language
  char		code[32];		// Language code
  ipp_tag_t	temp_tag;		// Temporary value tag


  DEBUG_printf("ippSetValueTag(ipp=%p, attr=%p(%p), value_tag=0x%x(%s))", ipp, attr, attr ? *attr : NULL, value_tag, ippTagString(value_tag));

  // Range check input...
  if (!ipp || !attr || !*attr)
    return (false);

  // If there is no change, return immediately...
  temp_tag = (ipp_tag_t)((int)((*attr)->value_tag) & IPP_TAG_CUPS_MASK);

  if (value_tag == temp_tag)
  {
    DEBUG_puts("2ippSetValueTag: No change.");
    return (true);
  }

  // Otherwise implement changes as needed...
  switch (value_tag)
  {
    case IPP_TAG_UNSUPPORTED_VALUE :
    case IPP_TAG_DEFAULT :
    case IPP_TAG_UNKNOWN :
    case IPP_TAG_NOVALUE :
    case IPP_TAG_NOTSETTABLE :
    case IPP_TAG_DELETEATTR :
    case IPP_TAG_ADMINDEFINE :
        // Free any existing values...
        if ((*attr)->num_values > 0)
          ipp_free_values(*attr, 0, (*attr)->num_values);

        // Set out-of-band value...
        (*attr)->value_tag = value_tag;
        break;

    case IPP_TAG_RANGE :
        if (temp_tag != IPP_TAG_INTEGER)
        {
          DEBUG_printf("2ippSetValueTag: Unable to convert %s to rangeOfInteger.", ippTagString(temp_tag));
          return (false);
        }

        for (i = (*attr)->num_values, value = (*attr)->values; i > 0; i --, value ++)
        {
          integer            = value->integer;
          value->range.lower = value->range.upper = integer;
          DEBUG_printf("2ippSetValueTag: values[%u].lower=%d, .upper=%d", (unsigned)((*attr)->num_values - i), value->range.lower, value->range.upper);
        }

        (*attr)->value_tag = IPP_TAG_RANGE;
        break;

    case IPP_TAG_NAME :
        if (temp_tag != IPP_TAG_KEYWORD)
        {
          DEBUG_printf("2ippSetValueTag: Unable to convert %s to name.", ippTagString(temp_tag));
          return (false);
        }

        (*attr)->value_tag = (ipp_tag_t)(IPP_TAG_NAME | ((*attr)->value_tag & IPP_TAG_CUPS_CONST));
        break;

    case IPP_TAG_NAMELANG :
    case IPP_TAG_TEXTLANG :
        if (value_tag == IPP_TAG_NAMELANG && (temp_tag != IPP_TAG_NAME && temp_tag != IPP_TAG_KEYWORD))
        {
          DEBUG_printf("2ippSetValueTag: Unable to convert %s to nameWithLanguage.", ippTagString(temp_tag));
          return (false);
        }

        if (value_tag == IPP_TAG_TEXTLANG && temp_tag != IPP_TAG_TEXT)
        {
          DEBUG_printf("2ippSetValueTag: Unable to convert %s to textWithLanguage.", ippTagString(temp_tag));
          return (false);
        }

        if (ipp->attrs && ipp->attrs->next && ipp->attrs->next->name && !strcmp(ipp->attrs->next->name, "attributes-natural-language") && (ipp->attrs->next->value_tag & IPP_TAG_CUPS_MASK) == IPP_TAG_LANGUAGE)
        {
          // Use the language code from the IPP message...
	  (*attr)->values[0].string.language = _cupsStrAlloc(ipp->attrs->next->values[0].string.text);
        }
        else
        {
          // Otherwise, use the language code corresponding to the locale...
	  language = cupsLangDefault();
	  (*attr)->values[0].string.language = _cupsStrAlloc(ipp_lang_code(cupsLangGetName(language), code, sizeof(code)));
        }

	DEBUG_printf("2ippSetValueTag: values[0].string.language=\"%s\"(%p)", (*attr)->values[0].string.language, (*attr)->values[0].string.language);

        for (i = (*attr)->num_values - 1, value = (*attr)->values + 1; i > 0; i --, value ++)
        {
          value->string.language = (*attr)->values[0].string.language;
          DEBUG_printf("2ippSetValueTag: values[%u].string.language=\"%s\"(%s)", (unsigned)((*attr)->num_values - i), value->string.language, value->string.language);
        }

        if ((int)(*attr)->value_tag & IPP_TAG_CUPS_CONST)
        {
          // Make copies of all values...
	  for (i = (*attr)->num_values, value = (*attr)->values; i > 0; i --, value ++)
	  {
	    value->string.text = _cupsStrAlloc(value->string.text);
	    DEBUG_printf("2ippSetValueTag: values[%u].string.text=\"%s\"(%s)", (unsigned)((*attr)->num_values - i), value->string.text, value->string.text);
	  }
        }

        (*attr)->value_tag = IPP_TAG_NAMELANG;
        break;

    case IPP_TAG_KEYWORD :
        if (temp_tag == IPP_TAG_NAME || temp_tag == IPP_TAG_NAMELANG)
        {
          DEBUG_printf("2ippSetValueTag: Ignoring change of %s to keyword.", ippTagString(temp_tag));
          break;			// Silently "allow" name -> keyword
        }

        DEBUG_printf("2ippSetValueTag: Unable to convert %s to keyword.", ippTagString(temp_tag));
        return (false);

    case IPP_TAG_EXTENSION :
        if (temp_tag == IPP_TAG_STRING && value_tag == IPP_TAG_EXTENSION)
        {
          // Allow octetString -> extension
          (*attr)->value_tag = value_tag;
          DEBUG_puts("2ippSetValueTag: Changing octetString to extension.");
          break;
        }

    default :
        DEBUG_printf("2ippSetValueTag: Unable to convert %s to %s.", ippTagString(temp_tag), ippTagString(value_tag));
        return (false);
  }

  DEBUG_puts("2ippSetValueTag: Successful.");
  return (true);
}


//
// 'ippSetVersion()' - Set the version number in an IPP message.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The valid version numbers are currently 1.0, 1.1, 2.0, 2.1, and 2.2.
//

bool					// O - `true` on success, `false` on failure
ippSetVersion(ipp_t *ipp,		// I - IPP message
              int   major,		// I - Major version number (major.minor)
              int   minor)		// I - Minor version number (major.minor)
{
  // Range check input...
  if (!ipp || major < 0 || minor < 0)
    return (false);

  // Set the version number...
  ipp->request.version[0] = (ipp_uchar_t)major;
  ipp->request.version[1] = (ipp_uchar_t)minor;

  return (true);
}


//
// 'ippTimeToDate()' - Convert from time in seconds to RFC 2579 format.
//

const ipp_uchar_t *			// O - RFC-2579 date/time data
ippTimeToDate(time_t t)			// I - Time in seconds
{
  struct tm	unixdate;		// UNIX unixdate/time info
  ipp_uchar_t	*date = _cupsGlobals()->ipp_date;
					// RFC-2579 date/time data


  // RFC-2579 date/time format is:
  //
  //   Byte(s)  Description
  //   -------  -----------
  //   0-1      Year (0 to 65535)
  //   2        Month (1 to 12)
  //   3        Day (1 to 31)
  //   4        Hours (0 to 23)
  //   5        Minutes (0 to 59)
  //   6        Seconds (0 to 60, 60 = "leap second")
  //   7        Deciseconds (0 to 9)
  //   8        +/- UTC
  //   9        UTC hours (0 to 11)
  //   10       UTC minutes (0 to 59)
  gmtime_r(&t, &unixdate);
  unixdate.tm_year += 1900;

  date[0]  = (ipp_uchar_t)(unixdate.tm_year >> 8);
  date[1]  = (ipp_uchar_t)(unixdate.tm_year);
  date[2]  = (ipp_uchar_t)(unixdate.tm_mon + 1);
  date[3]  = (ipp_uchar_t)unixdate.tm_mday;
  date[4]  = (ipp_uchar_t)unixdate.tm_hour;
  date[5]  = (ipp_uchar_t)unixdate.tm_min;
  date[6]  = (ipp_uchar_t)unixdate.tm_sec;
  date[7]  = 0;
  date[8]  = '+';
  date[9]  = 0;
  date[10] = 0;

  return (date);
}


//
// 'ippValidateAttribute()' - Validate the contents of an attribute.
//
// This function validates the contents of an attribute based on the name and
// value tag.  `true` is returned if the attribute is valid, `false` otherwise.
// On failure, @link cupsGetErrorString@ is set to a human-readable message.
//

bool					// O - `true` if valid, `false` otherwise
ippValidateAttribute(
    ipp_attribute_t *attr)		// I - Attribute
{
  ipp_tag_t	value_tag;		// Masked value tag
  _ipp_value_t	*value;			// Current value
  size_t	i;			// Looping var
  char		scheme[64],		// Scheme from URI
		userpass[256],		// Username/password from URI
		hostname[256],		// Hostname from URI
		resource[1024];		// Resource from URI
  int		port,			// Port number from URI
		uri_status;		// URI separation status
  const char	*ptr;			// Pointer into string
  ipp_attribute_t *colattr;		// Collection attribute
  ipp_uchar_t	*date;			// Current date value


  // Skip separators.
  if (!attr->name)
    return (true);

  // Validate the attribute name.
  for (ptr = attr->name; *ptr; ptr ++)
  {
    if (!isalnum(*ptr & 255) && *ptr != '-' && *ptr != '.' && *ptr != '_')
      break;
  }

  if (*ptr || ptr == attr->name)
  {
    ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad attribute name - invalid character (RFC 8011 section 5.1.4)."), attr->name);
    return (false);
  }

  if ((ptr - attr->name) > 255)
  {
    ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad attribute name - bad length %d (RFC 8011 section 5.1.4)."), attr->name, (int)(ptr - attr->name));
    return (false);
  }

  value_tag = attr->value_tag & IPP_TAG_CUPS_MASK;

  switch (value_tag)
  {
    case IPP_TAG_INTEGER :
        break;

    case IPP_TAG_BOOLEAN :
        for (i = attr->num_values, value = attr->values; i > 0; i --, value ++)
	{
	  if (value->boolean != 0 && value->boolean != 1)
	  {
	    ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad boolean value %d (RFC 8011 section 5.1.21)."), attr->name, value->boolean);
	    return (false);
	  }
	}
        break;

    case IPP_TAG_ENUM :
        for (i = attr->num_values, value = attr->values; i > 0; i --, value ++)
	{
	  if (value->integer < 1)
	  {
	    ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad enum value %d - out of range (RFC 8011 section 5.1.5)."), attr->name, value->integer);
            return (false);
	  }
	}
        break;

    case IPP_TAG_STRING :
        for (i = attr->num_values, value = attr->values; i > 0; i --, value ++)
	{
	  if (value->unknown.length > IPP_MAX_OCTETSTRING)
	  {
	    ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad octetString value - bad length %d (RFC 8011 section 5.1.20)."), attr->name, value->unknown.length);
	    return (false);
	  }
	}
        break;

    case IPP_TAG_DATE :
        for (i = attr->num_values, value = attr->values; i > 0; i --, value ++)
	{
	  date = value->date;

          if (date[2] < 1 || date[2] > 12)
	  {
	    ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad dateTime month %u (RFC 8011 section 5.1.15)."), attr->name, date[2]);
	    return (false);
	  }

          if (date[3] < 1 || date[3] > 31)
	  {
	    ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad dateTime day %u (RFC 8011 section 5.1.15)."), attr->name, date[3]);
	    return (false);
	  }

          if (date[4] > 23)
	  {
	    ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad dateTime hours %u (RFC 8011 section 5.1.15)."), attr->name, date[4]);
	    return (false);
	  }

          if (date[5] > 59)
	  {
	    ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad dateTime minutes %u (RFC 8011 section 5.1.15)."), attr->name, date[5]);
	    return (false);
	  }

          if (date[6] > 60)
	  {
	    ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad dateTime seconds %u (RFC 8011 section 5.1.15)."), attr->name, date[6]);
	    return (false);
	  }

          if (date[7] > 9)
	  {
	    ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad dateTime deciseconds %u (RFC 8011 section 5.1.15)."), attr->name, date[7]);
	    return (false);
	  }

          if (date[8] != '-' && date[8] != '+')
	  {
	    ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad dateTime UTC sign '%c' (RFC 8011 section 5.1.15)."), attr->name, date[8]);
	    return (false);
	  }

          if (date[9] > 14)
	  {
	    // Kiribata has a UTC+14 time zone, RFC 2579 calls for UTC+13 support, errata filed...
	    ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad dateTime UTC hours %u (RFC 8011 section 5.1.15)."), attr->name, date[9]);
	    return (false);
	  }

          if (date[10] > 59)
	  {
	    ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad dateTime UTC minutes %u (RFC 8011 section 5.1.15)."), attr->name, date[10]);
	    return (false);
	  }
	}
        break;

    case IPP_TAG_RESOLUTION :
        for (i = attr->num_values, value = attr->values; i > 0; i --, value ++)
	{
	  if (value->resolution.xres <= 0)
	  {
	    ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad resolution value %dx%d%s - cross feed resolution must be positive (RFC 8011 section 5.1.16)."), attr->name, value->resolution.xres, value->resolution.yres, value->resolution.units == IPP_RES_PER_INCH ? "dpi" : value->resolution.units == IPP_RES_PER_CM ? "dpcm" : "unknown");
	    return (false);
	  }

	  if (value->resolution.yres <= 0)
	  {
	    ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad resolution value %dx%d%s - feed resolution must be positive (RFC 8011 section 5.1.16)."), attr->name, value->resolution.xres, value->resolution.yres, value->resolution.units == IPP_RES_PER_INCH ? "dpi" : value->resolution.units == IPP_RES_PER_CM ? "dpcm" : "unknown");
            return (false);
	  }

	  if (value->resolution.units != IPP_RES_PER_INCH && value->resolution.units != IPP_RES_PER_CM)
	  {
	    ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad resolution value %dx%d%s - bad units value (RFC 8011 section 5.1.16)."), attr->name, value->resolution.xres, value->resolution.yres, value->resolution.units == IPP_RES_PER_INCH ? "dpi" : value->resolution.units == IPP_RES_PER_CM ? "dpcm" : "unknown");
	    return (false);
	  }
	}
        break;

    case IPP_TAG_RANGE :
        for (i = attr->num_values, value = attr->values; i > 0; i --, value ++)
	{
	  if (value->range.lower > value->range.upper)
	  {
	    ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad rangeOfInteger value %d-%d - lower greater than upper (RFC 8011 section 5.1.14)."), attr->name, value->range.lower, value->range.upper);
	    return (false);
	  }
	}
        break;

    case IPP_TAG_BEGIN_COLLECTION :
        for (i = attr->num_values, value = attr->values; i > 0; i --, value ++)
	{
	  for (colattr = value->collection->attrs;
	       colattr;
	       colattr = colattr->next)
	  {
	    if (!ippValidateAttribute(colattr))
	      return (false);
	  }
	}
        break;

    case IPP_TAG_TEXT :
    case IPP_TAG_TEXTLANG :
        if (value_tag == IPP_TAG_TEXTLANG)
        {
          if (!ipp_regex_begin())
            return (false);
        }

        for (i = attr->num_values, value = attr->values; i > 0; i --, value ++)
	{
	  if (value_tag == IPP_TAG_TEXTLANG && !ipp_is_valid_language(attr->name, value->string.language))
	  {
	    ipp_regex_end();
	    return (false);
	  }

	  for (ptr = value->string.text; *ptr; ptr ++)
	  {
	    if ((*ptr & 0xe0) == 0xc0)
	    {
	      if ((ptr[1] & 0xc0) != 0x80)
	        break;

	      ptr ++;
	    }
	    else if ((*ptr & 0xf0) == 0xe0)
	    {
	      if ((ptr[1] & 0xc0) != 0x80 || (ptr[2] & 0xc0) != 0x80)
	        break;

	      ptr += 2;
	    }
	    else if ((*ptr & 0xf8) == 0xf0)
	    {
	      if ((ptr[1] & 0xc0) != 0x80 || (ptr[2] & 0xc0) != 0x80 || (ptr[3] & 0xc0) != 0x80)
	        break;

	      ptr += 3;
	    }
	    else if (*ptr & 0x80)
	    {
	      break;
	    }
	    else if ((*ptr < ' ' && *ptr != '\n' && *ptr != '\r' && *ptr != '\t') || *ptr == 0x7f)
	    {
	      break;
	    }
	  }

          if (*ptr)
          {
	    if (value_tag == IPP_TAG_TEXTLANG)
	      ipp_regex_end();

	    if (*ptr < ' ' || *ptr == 0x7f)
	    {
	      ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad text value \"%s\" - bad control character (PWG 5100.14 section 8.3)."), attr->name, value->string.text);
	      return (false);
	    }
	    else
	    {
	      ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad text value \"%s\" - bad UTF-8 sequence (RFC 8011 section 5.1.2)."), attr->name, value->string.text);
	      return (false);
	    }
          }

	  if ((ptr - value->string.text) > (IPP_MAX_TEXT - 1))
	  {
	    if (value_tag == IPP_TAG_TEXTLANG)
	      ipp_regex_end();

	    ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad text value \"%s\" - bad length %d (RFC 8011 section 5.1.2)."), attr->name, value->string.text, (int)(ptr - value->string.text));
	    return (false);
	  }
	}

	if (value_tag == IPP_TAG_TEXTLANG)
	  ipp_regex_end();
        break;

    case IPP_TAG_NAME :
    case IPP_TAG_NAMELANG :
        if (value_tag == IPP_TAG_NAMELANG)
        {
          if (!ipp_regex_begin())
            return (false);
        }

        for (i = attr->num_values, value = attr->values; i > 0; i --, value ++)
	{
	  if (value_tag == IPP_TAG_NAMELANG && !ipp_is_valid_language(attr->name, value->string.language))
	  {
	    ipp_regex_end();
	    return (false);
	  }

	  for (ptr = value->string.text; *ptr; ptr ++)
	  {
	    if ((*ptr & 0xe0) == 0xc0)
	    {
	      if ((ptr[1] & 0xc0) != 0x80)
	        break;

	      ptr ++;
	    }
	    else if ((*ptr & 0xf0) == 0xe0)
	    {
	      if ((ptr[1] & 0xc0) != 0x80 || (ptr[2] & 0xc0) != 0x80)
	        break;

	      ptr += 2;
	    }
	    else if ((*ptr & 0xf8) == 0xf0)
	    {
	      if ((ptr[1] & 0xc0) != 0x80 || (ptr[2] & 0xc0) != 0x80 || (ptr[3] & 0xc0) != 0x80)
	        break;

	      ptr += 3;
	    }
	    else if (*ptr & 0x80)
	    {
	      break;
	    }
	    else if (*ptr < ' ' || *ptr == 0x7f)
	    {
	      break;
	    }
	  }

	  if (*ptr)
	  {
	    if (value_tag == IPP_TAG_NAMELANG)
	      ipp_regex_end();

	    if (*ptr < ' ' || *ptr == 0x7f)
	    {
	      ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad name value \"%s\" - bad control character (PWG 5100.14 section 8.1)."), attr->name, value->string.text);
	      return (false);
	    }
	    else
	    {
	      ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad name value \"%s\" - bad UTF-8 sequence (RFC 8011 section 5.1.3)."), attr->name, value->string.text);
	      return (false);
	    }
          }

	  if ((ptr - value->string.text) > (IPP_MAX_NAME - 1))
	  {
	    if (value_tag == IPP_TAG_NAMELANG)
	      ipp_regex_end();

	    ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad name value \"%s\" - bad length %d (RFC 8011 section 5.1.3)."), attr->name, value->string.text, (int)(ptr - value->string.text));
	    return (false);
	  }
	}

	if (value_tag == IPP_TAG_NAMELANG)
	  ipp_regex_end();
        break;

    case IPP_TAG_KEYWORD :
        for (i = attr->num_values, value = attr->values; i > 0; i --, value ++)
	{
	  for (ptr = value->string.text; *ptr; ptr ++)
	  {
	    if (!isalnum(*ptr & 255) && *ptr != '-' && *ptr != '.' && *ptr != '_')
	      break;
	  }

	  if (*ptr || ptr == value->string.text)
	  {
	    ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad keyword value \"%s\" - invalid character (RFC 8011 section 5.1.4)."), attr->name, value->string.text);
	    return (false);
	  }

	  if ((ptr - value->string.text) > (IPP_MAX_KEYWORD - 1))
	  {
	    ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad keyword value \"%s\" - bad length %d (RFC 8011 section 5.1.4)."), attr->name, value->string.text, (int)(ptr - value->string.text));
	    return (false);
	  }
	}
        break;

    case IPP_TAG_URI :
        for (i = attr->num_values, value = attr->values; i > 0; i --, value ++)
	{
	  uri_status = httpSeparateURI(HTTP_URI_CODING_ALL, value->string.text, scheme, sizeof(scheme), userpass, sizeof(userpass), hostname, sizeof(hostname), &port, resource, sizeof(resource));

	  if (uri_status < HTTP_URI_STATUS_OK)
	  {
	    ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad URI value \"%s\" - %s (RFC 8011 section 5.1.6)."), attr->name, value->string.text, httpURIStatusString(uri_status));
	    return (false);
	  }

	  if (strlen(value->string.text) > (IPP_MAX_URI - 1))
	  {
	    ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad URI value \"%s\" - bad length %d (RFC 8011 section 5.1.6)."), attr->name, value->string.text, (int)strlen(value->string.text));
	  }
	}
        break;

    case IPP_TAG_URISCHEME :
        for (i = attr->num_values, value = attr->values; i > 0; i --, value ++)
	{
	  ptr = value->string.text;
	  if (islower(*ptr & 255))
	  {
	    for (ptr ++; *ptr; ptr ++)
	    {
	      if (!islower(*ptr & 255) && !isdigit(*ptr & 255) && *ptr != '+' && *ptr != '-' && *ptr != '.')
                break;
	    }
	  }

	  if (*ptr || ptr == value->string.text)
	  {
	    ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad uriScheme value \"%s\" - bad characters (RFC 8011 section 5.1.7)."), attr->name, value->string.text);
	    return (false);
	  }

	  if ((ptr - value->string.text) > (IPP_MAX_URISCHEME - 1))
	  {
	    ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad uriScheme value \"%s\" - bad length %d (RFC 8011 section 5.1.7)."), attr->name, value->string.text, (int)(ptr - value->string.text));
	    return (false);
	  }
	}
        break;

    case IPP_TAG_CHARSET :
        for (i = attr->num_values, value = attr->values; i > 0; i --, value ++)
	{
	  for (ptr = value->string.text; *ptr; ptr ++)
	  {
	    if (!isprint(*ptr & 255) || isupper(*ptr & 255) || isspace(*ptr & 255))
	      break;
	  }

	  if (*ptr || ptr == value->string.text)
	  {
	    ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad charset value \"%s\" - bad characters (RFC 8011 section 5.1.8)."), attr->name, value->string.text);
	    return (false);
	  }

	  if ((ptr - value->string.text) > (IPP_MAX_CHARSET - 1))
	  {
	    ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad charset value \"%s\" - bad length %d (RFC 8011 section 5.1.8)."), attr->name, value->string.text, (int)(ptr - value->string.text));
	    return (false);
	  }
	}
        break;

    case IPP_TAG_LANGUAGE :
        if (!ipp_regex_begin())
          return (false);

        for (i = attr->num_values, value = attr->values; i > 0; i --, value ++)
	{
	  if (!ipp_is_valid_language(attr->name, value->string.text))
	  {
	    ipp_regex_end();
	    return (false);
	  }
	}

	ipp_regex_end();
        break;

    case IPP_TAG_MIMETYPE :
        if (!ipp_regex_begin())
          return (false);

        for (i = attr->num_values, value = attr->values; i > 0; i --, value ++)
	{
	  if (!ipp_is_valid_mimetype(attr->name, value->string.text))
	  {
	    ipp_regex_end();
	    return (false);
	  }
	}

	ipp_regex_end();
        break;

    default :
        break;
  }

  return (true);
}


//
// 'ippValidateAttributes()' - Validate all attributes in an IPP message.
//
// This function validates the contents of the IPP message, including each
// attribute.  Like @link ippValidateAttribute@, @link cupsGetErrorString@ is
// set to a human-readable message on failure.
//

bool					// O - `true` if valid, `false` otherwise
ippValidateAttributes(ipp_t *ipp)	// I - IPP message
{
  ipp_attribute_t	*attr;		// Current attribute


  if (!ipp)
    return (true);

  for (attr = ipp->attrs; attr; attr = attr->next)
  {
    if (!ippValidateAttribute(attr))
      return (false);
  }

  return (true);
}


//
// 'ippWrite()' - Write data for an IPP message to a HTTP connection.
//

ipp_state_t				// O - Current state
ippWrite(http_t *http,			// I - HTTP connection
         ipp_t  *ipp)			// I - IPP data
{
  DEBUG_printf("ippWrite(http=%p, ipp=%p)", (void *)http, (void *)ipp);

  if (!http)
    return (IPP_STATE_ERROR);

  return (ippWriteIO(http, (ipp_io_cb_t)httpWrite, http->blocking, NULL, ipp));
}


//
// 'ippWriteFile()' - Write data for an IPP message to a file.
//

ipp_state_t				// O - Current state
ippWriteFile(int   fd,			// I - HTTP data
             ipp_t *ipp)		// I - IPP data
{
  DEBUG_printf("ippWriteFile(fd=%d, ipp=%p)", fd, (void *)ipp);

  ipp->state = IPP_STATE_IDLE;

  return (ippWriteIO(&fd, (ipp_io_cb_t)ipp_write_file, true, NULL, ipp));
}


//
// 'ippWriteIO()' - Write data for an IPP message.
//

ipp_state_t				// O - Current state
ippWriteIO(void        *dst,		// I - Destination
           ipp_io_cb_t cb,		// I - Write callback function
	   bool        blocking,	// I - Use blocking IO?
	   ipp_t       *parent,		// I - Parent IPP message
           ipp_t       *ipp)		// I - IPP data
{
  size_t		i;		// Looping var
  int			n;		// Length of data
  unsigned char		*buffer,	// Data buffer
			*bufptr;	// Pointer into buffer
  ipp_attribute_t	*attr;		// Current attribute
  _ipp_value_t		*value;		// Current value


  DEBUG_printf("ippWriteIO(dst=%p, cb=%p, blocking=%d, parent=%p, ipp=%p)", (void *)dst, (void *)cb, blocking, (void *)parent, (void *)ipp);

  if (!dst || !ipp)
    return (IPP_STATE_ERROR);

  if ((buffer = (unsigned char *)_cupsBufferGet(IPP_BUF_SIZE)) == NULL)
  {
    DEBUG_puts("1ippWriteIO: Unable to get write buffer");
    return (IPP_STATE_ERROR);
  }

  switch (ipp->state)
  {
    case IPP_STATE_IDLE :
        ipp->state ++; // Avoid common problem...

    case IPP_STATE_HEADER :
        if (parent == NULL)
	{
	  // Send the request header:
	  //
	  //                 Version = 2 bytes
	  //   Operation/Status Code = 2 bytes
	  //              Request ID = 4 bytes
	  //                   Total = 8 bytes
          bufptr = buffer;

	  *bufptr++ = ipp->request.version[0];
	  *bufptr++ = ipp->request.version[1];
	  *bufptr++ = (ipp_uchar_t)(ipp->request.op_status >> 8);
	  *bufptr++ = (ipp_uchar_t)ipp->request.op_status;
	  *bufptr++ = (ipp_uchar_t)(ipp->request.request_id >> 24);
	  *bufptr++ = (ipp_uchar_t)(ipp->request.request_id >> 16);
	  *bufptr++ = (ipp_uchar_t)(ipp->request.request_id >> 8);
	  *bufptr++ = (ipp_uchar_t)ipp->request.request_id;

	  DEBUG_printf("2ippWriteIO: version=%d.%d", buffer[0], buffer[1]);
	  DEBUG_printf("2ippWriteIO: op_status=%04x", ipp->request.op_status);
	  DEBUG_printf("2ippWriteIO: request_id=%d", ipp->request.request_id);

          if ((*cb)(dst, buffer, (size_t)(bufptr - buffer)) < 0)
	  {
	    DEBUG_puts("1ippWriteIO: Could not write IPP header...");
	    _cupsBufferRelease((char *)buffer);
	    return (IPP_STATE_ERROR);
	  }
	}

	// Reset the state engine to point to the first attribute
	// in the request/response, with no current group.
        ipp->state   = IPP_STATE_ATTRIBUTE;
	ipp->current = ipp->attrs;
	ipp->curtag  = IPP_TAG_ZERO;

	DEBUG_printf("1ippWriteIO: ipp->current=%p", (void *)ipp->current);

        // If blocking is disabled, stop here...
        if (!blocking)
	  break;

    case IPP_STATE_ATTRIBUTE :
        while (ipp->current != NULL)
	{
	  // Write this attribute...
	  bufptr = buffer;
	  attr   = ipp->current;

	  ipp->current = ipp->current->next;

          if (!parent)
	  {
	    if (ipp->curtag != attr->group_tag)
	    {
	      // Send a group tag byte...
	      ipp->curtag = attr->group_tag;

	      if (attr->group_tag == IPP_TAG_ZERO)
		continue;

	      DEBUG_printf("2ippWriteIO: wrote group tag=%x(%s)", attr->group_tag, ippTagString(attr->group_tag));
	      *bufptr++ = (ipp_uchar_t)attr->group_tag;
	    }
	    else if (attr->group_tag == IPP_TAG_ZERO)
	    {
	      continue;
	    }
	  }

	  DEBUG_printf("1ippWriteIO: %s (%s%s)", attr->name, attr->num_values > 1 ? "1setOf " : "", ippTagString(attr->value_tag));

	  // Write the attribute tag and name.
	  //
	  // The attribute name length does not include the trailing nul
	  // character in the source string.
	  //
	  // Collection values (parent != NULL) are written differently...
          if (parent == NULL)
	  {
	    // Get the length of the attribute name, and make sure it won't overflow the buffer...
            if ((n = (int)strlen(attr->name)) > (IPP_BUF_SIZE - 8))
	    {
	      DEBUG_printf("1ippWriteIO: Attribute name too long (%d)", n);
	      _cupsBufferRelease((char *)buffer);
	      return (IPP_STATE_ERROR);
	    }

	    // Write the value tag, name length, and name string...
	    DEBUG_printf("2ippWriteIO: writing value tag=%x(%s)", attr->value_tag, ippTagString(attr->value_tag));
            DEBUG_printf("2ippWriteIO: writing name=%d,\"%s\"", n, attr->name);

	    *bufptr++ = (ipp_uchar_t)attr->value_tag;
	    *bufptr++ = (ipp_uchar_t)(n >> 8);
	    *bufptr++ = (ipp_uchar_t)n;
	    memcpy(bufptr, attr->name, (size_t)n);
	    bufptr += n;
          }
	  else
	  {
	    // Get the length of the attribute name, and make sure it won't overflow the buffer...
            if ((n = (int)strlen(attr->name)) > (IPP_BUF_SIZE - 12))
	    {
	      DEBUG_printf("1ippWriteIO: Attribute name too long (%d)", n);
	      _cupsBufferRelease((char *)buffer);
	      return (IPP_STATE_ERROR);
	    }

	    // Write the member name tag, name length, name string, value tag,
	    // and empty name for the collection member attribute...
            DEBUG_printf("2ippWriteIO: writing value tag=%x(memberName)", IPP_TAG_MEMBERNAME);
            DEBUG_printf("2ippWriteIO: writing name=%d,\"%s\"", n, attr->name);
            DEBUG_printf("2ippWriteIO: writing value tag=%x(%s)", attr->value_tag, ippTagString(attr->value_tag));
            DEBUG_puts("2ippWriteIO: writing name=0,\"\"");

            *bufptr++ = IPP_TAG_MEMBERNAME;
	    *bufptr++ = 0;
	    *bufptr++ = 0;
	    *bufptr++ = (ipp_uchar_t)(n >> 8);
	    *bufptr++ = (ipp_uchar_t)n;
	    memcpy(bufptr, attr->name, (size_t)n);
	    bufptr += n;

            if (attr->value_tag > 0xff)
            {
              *bufptr++ = IPP_TAG_EXTENSION;
	      *bufptr++ = (ipp_uchar_t)(attr->value_tag >> 24);
	      *bufptr++ = (ipp_uchar_t)(attr->value_tag >> 16);
	      *bufptr++ = (ipp_uchar_t)(attr->value_tag >> 8);
	      *bufptr++ = (ipp_uchar_t)attr->value_tag;
            }
            else
            {
	      *bufptr++ = (ipp_uchar_t)attr->value_tag;
	    }

            *bufptr++ = 0;
            *bufptr++ = 0;
	  }

	  // Now write the attribute value(s)...
	  switch (attr->value_tag & ~IPP_TAG_CUPS_CONST)
	  {
	    case IPP_TAG_UNSUPPORTED_VALUE :
	    case IPP_TAG_DEFAULT :
	    case IPP_TAG_UNKNOWN :
	    case IPP_TAG_NOVALUE :
	    case IPP_TAG_NOTSETTABLE :
	    case IPP_TAG_DELETEATTR :
	    case IPP_TAG_ADMINDEFINE :
		*bufptr++ = 0;
		*bufptr++ = 0;
	        break;

	    case IPP_TAG_INTEGER :
	    case IPP_TAG_ENUM :
	        for (i = 0, value = attr->values; i < attr->num_values; i ++, value ++)
		{
                  if ((IPP_BUF_SIZE - (bufptr - buffer)) < 9)
		  {
                    if ((*cb)(dst, buffer, (size_t)(bufptr - buffer)) < 0)
	            {
		      DEBUG_puts("1ippWriteIO: Could not write IPP attribute...");
		      _cupsBufferRelease((char *)buffer);
	              return (IPP_STATE_ERROR);
	            }

		    bufptr = buffer;
		  }

		  if (i)
		  {
		    // Arrays and sets are done by sending additional values with a zero-length name...
                    *bufptr++ = (ipp_uchar_t)attr->value_tag;
		    *bufptr++ = 0;
		    *bufptr++ = 0;
		  }

	          // Integers and enumerations are both 4-byte signed
		  // (twos-complement) values.
		  //
		  // Put the 2-byte length and 4-byte value into the buffer...
	          *bufptr++ = 0;
		  *bufptr++ = 4;
		  *bufptr++ = (ipp_uchar_t)(value->integer >> 24);
		  *bufptr++ = (ipp_uchar_t)(value->integer >> 16);
		  *bufptr++ = (ipp_uchar_t)(value->integer >> 8);
		  *bufptr++ = (ipp_uchar_t)value->integer;
		}
		break;

	    case IPP_TAG_BOOLEAN :
	        for (i = 0, value = attr->values; i < attr->num_values; i ++, value ++)
		{
                  if ((IPP_BUF_SIZE - (bufptr - buffer)) < 6)
		  {
                    if ((*cb)(dst, buffer, (size_t)(bufptr - buffer)) < 0)
	            {
		      DEBUG_puts("1ippWriteIO: Could not write IPP attribute...");
		      _cupsBufferRelease((char *)buffer);
	              return (IPP_STATE_ERROR);
	            }

		    bufptr = buffer;
		  }

		  if (i)
		  {
		    // Arrays and sets are done by sending additional values with a zero-length name...
                    *bufptr++ = (ipp_uchar_t)attr->value_tag;
		    *bufptr++ = 0;
		    *bufptr++ = 0;
		  }

		  // Boolean values are 1-byte; 0 = false, 1 = true.
		  //
		  // Put the 2-byte length and 1-byte value into the buffer...
	          *bufptr++ = 0;
		  *bufptr++ = 1;
		  *bufptr++ = (ipp_uchar_t)value->boolean;
		}
		break;

	    case IPP_TAG_TEXT :
	    case IPP_TAG_NAME :
	    case IPP_TAG_KEYWORD :
	    case IPP_TAG_URI :
	    case IPP_TAG_URISCHEME :
	    case IPP_TAG_CHARSET :
	    case IPP_TAG_LANGUAGE :
	    case IPP_TAG_MIMETYPE :
	        for (i = 0, value = attr->values; i < attr->num_values; i ++, value ++)
		{
		  if (i)
		  {
		    // Arrays and sets are done by sending additional values with a zero-length name...
        	    DEBUG_printf("2ippWriteIO: writing value tag=%x(%s)", attr->value_tag, ippTagString(attr->value_tag));
        	    DEBUG_printf("2ippWriteIO: writing name=0,\"\"");

                    if ((IPP_BUF_SIZE - (bufptr - buffer)) < 3)
		    {
                      if ((*cb)(dst, buffer, (size_t)(bufptr - buffer)) < 0)
	              {
			DEBUG_puts("1ippWriteIO: Could not write IPP attribute...");
			_cupsBufferRelease((char *)buffer);
	        	return (IPP_STATE_ERROR);
	              }

		      bufptr = buffer;
		    }

                    *bufptr++ = (ipp_uchar_t)attr->value_tag;
		    *bufptr++ = 0;
		    *bufptr++ = 0;
		  }

                  if (value->string.text != NULL)
                    n = (int)strlen(value->string.text);
		  else
		    n = 0;

                  if (n > (IPP_BUF_SIZE - 2))
		  {
		    DEBUG_printf("1ippWriteIO: String too long (%d)", n);
		    _cupsBufferRelease((char *)buffer);
		    return (IPP_STATE_ERROR);
		  }

                  DEBUG_printf("2ippWriteIO: writing string=%d,\"%s\"", n, value->string.text);

                  if ((int)(IPP_BUF_SIZE - (bufptr - buffer)) < (n + 2))
		  {
                    if ((*cb)(dst, buffer, (size_t)(bufptr - buffer)) < 0)
	            {
		      DEBUG_puts("1ippWriteIO: Could not write IPP attribute...");
		      _cupsBufferRelease((char *)buffer);
	              return (IPP_STATE_ERROR);
	            }

		    bufptr = buffer;
		  }

		  // All simple strings consist of the 2-byte length and
		  // character data without the trailing nul normally found
		  // in C strings.  Also, strings cannot be longer than IPP_MAX_LENGTH
		  // bytes since the 2-byte length is a signed (twos-complement)
		  // value.
		  //
		  // Put the 2-byte length and string characters in the buffer.
	          *bufptr++ = (ipp_uchar_t)(n >> 8);
		  *bufptr++ = (ipp_uchar_t)n;

		  if (n > 0)
		  {
		    memcpy(bufptr, value->string.text, (size_t)n);
		    bufptr += n;
		  }
		}
		break;

	    case IPP_TAG_DATE :
	        for (i = 0, value = attr->values; i < attr->num_values; i ++, value ++)
		{
                  if ((IPP_BUF_SIZE - (bufptr - buffer)) < 16)
		  {
                    if ((*cb)(dst, buffer, (size_t)(bufptr - buffer)) < 0)
	            {
		      DEBUG_puts("1ippWriteIO: Could not write IPP attribute...");
		      _cupsBufferRelease((char *)buffer);
	              return (IPP_STATE_ERROR);
	            }

		    bufptr = buffer;
		  }

		  if (i)
		  {
		    // Arrays and sets are done by sending additional values with a zero-length name...
                    *bufptr++ = (ipp_uchar_t)attr->value_tag;
		    *bufptr++ = 0;
		    *bufptr++ = 0;
		  }

		  // Date values consist of a 2-byte length and an
		  // 11-byte date/time structure defined by RFC 1903.
		  //
		  // Put the 2-byte length and 11-byte date/time
		  // structure in the buffer.
	          *bufptr++ = 0;
		  *bufptr++ = 11;
		  memcpy(bufptr, value->date, 11);
		  bufptr += 11;
		}
		break;

	    case IPP_TAG_RESOLUTION :
	        for (i = 0, value = attr->values; i < attr->num_values; i ++, value ++)
		{
                  if ((IPP_BUF_SIZE - (bufptr - buffer)) < 14)
		  {
                    if ((*cb)(dst, buffer, (size_t)(bufptr - buffer)) < 0)
	            {
		      DEBUG_puts("1ippWriteIO: Could not write IPP attribute...");
		      _cupsBufferRelease((char *)buffer);
		      return (IPP_STATE_ERROR);
	            }

		    bufptr = buffer;
		  }

		  if (i)
		  {
		    // Arrays and sets are done by sending additional values with a zero-length name...
                    *bufptr++ = (ipp_uchar_t)attr->value_tag;
		    *bufptr++ = 0;
		    *bufptr++ = 0;
		  }

		  // Resolution values consist of a 2-byte length,
		  // 4-byte horizontal resolution value, 4-byte vertical
		  // resolution value, and a 1-byte units value.
		  //
		  // Put the 2-byte length and resolution value data
		  // into the buffer.
	          *bufptr++ = 0;
		  *bufptr++ = 9;
		  *bufptr++ = (ipp_uchar_t)(value->resolution.xres >> 24);
		  *bufptr++ = (ipp_uchar_t)(value->resolution.xres >> 16);
		  *bufptr++ = (ipp_uchar_t)(value->resolution.xres >> 8);
		  *bufptr++ = (ipp_uchar_t)value->resolution.xres;
		  *bufptr++ = (ipp_uchar_t)(value->resolution.yres >> 24);
		  *bufptr++ = (ipp_uchar_t)(value->resolution.yres >> 16);
		  *bufptr++ = (ipp_uchar_t)(value->resolution.yres >> 8);
		  *bufptr++ = (ipp_uchar_t)value->resolution.yres;
		  *bufptr++ = (ipp_uchar_t)value->resolution.units;
		}
		break;

	    case IPP_TAG_RANGE :
	        for (i = 0, value = attr->values; i < attr->num_values; i ++, value ++)
		{
                  if ((IPP_BUF_SIZE - (bufptr - buffer)) < 13)
		  {
                    if ((*cb)(dst, buffer, (size_t)(bufptr - buffer)) < 0)
	            {
		      DEBUG_puts("1ippWriteIO: Could not write IPP attribute...");
		      _cupsBufferRelease((char *)buffer);
	              return (IPP_STATE_ERROR);
	            }

		    bufptr = buffer;
		  }

		  if (i)
		  {
		    // Arrays and sets are done by sending additional values with a zero-length name...
                    *bufptr++ = (ipp_uchar_t)attr->value_tag;
		    *bufptr++ = 0;
		    *bufptr++ = 0;
		  }

		  // Range values consist of a 2-byte length,
		  // 4-byte lower value, and 4-byte upper value.
		  //
		  // Put the 2-byte length and range value data
		  // into the buffer.
	          *bufptr++ = 0;
		  *bufptr++ = 8;
		  *bufptr++ = (ipp_uchar_t)(value->range.lower >> 24);
		  *bufptr++ = (ipp_uchar_t)(value->range.lower >> 16);
		  *bufptr++ = (ipp_uchar_t)(value->range.lower >> 8);
		  *bufptr++ = (ipp_uchar_t)value->range.lower;
		  *bufptr++ = (ipp_uchar_t)(value->range.upper >> 24);
		  *bufptr++ = (ipp_uchar_t)(value->range.upper >> 16);
		  *bufptr++ = (ipp_uchar_t)(value->range.upper >> 8);
		  *bufptr++ = (ipp_uchar_t)value->range.upper;
		}
		break;

	    case IPP_TAG_TEXTLANG :
	    case IPP_TAG_NAMELANG :
	        for (i = 0, value = attr->values; i < attr->num_values; i ++, value ++)
		{
		  if (i)
		  {
		    // Arrays and sets are done by sending additional values with a zero-length name...
                    if ((IPP_BUF_SIZE - (bufptr - buffer)) < 3)
		    {
                      if ((*cb)(dst, buffer, (size_t)(bufptr - buffer)) < 0)
	              {
			DEBUG_puts("1ippWriteIO: Could not write IPP attribute...");
			_cupsBufferRelease((char *)buffer);
	        	return (IPP_STATE_ERROR);
	              }

		      bufptr = buffer;
		    }

                    *bufptr++ = (ipp_uchar_t)attr->value_tag;
		    *bufptr++ = 0;
		    *bufptr++ = 0;
		  }

		  // textWithLanguage and nameWithLanguage values consist
		  // of a 2-byte length for both strings and their
		  // individual lengths, a 2-byte length for the
		  // character string, the character string without the
		  // trailing nul, a 2-byte length for the character
		  // set string, and the character set string without
		  // the trailing nul.
                  n = 4;

		  if (value->string.language != NULL)
                    n += (int)strlen(value->string.language);

		  if (value->string.text != NULL)
                    n += (int)strlen(value->string.text);

                  if (n > (IPP_BUF_SIZE - 2))
		  {
		    DEBUG_printf("1ippWriteIO: text/nameWithLanguage value too long (%d)", n);
		    _cupsBufferRelease((char *)buffer);
		    return (IPP_STATE_ERROR);
                  }

                  if ((int)(IPP_BUF_SIZE - (bufptr - buffer)) < (n + 2))
		  {
                    if ((*cb)(dst, buffer, (size_t)(bufptr - buffer)) < 0)
	            {
		      DEBUG_puts("1ippWriteIO: Could not write IPP attribute...");
		      _cupsBufferRelease((char *)buffer);
	              return (IPP_STATE_ERROR);
	            }

		    bufptr = buffer;
		  }

		  // Length of entire value
	          *bufptr++ = (ipp_uchar_t)(n >> 8);
		  *bufptr++ = (ipp_uchar_t)n;

		  // Length of language
		  if (value->string.language != NULL)
		    n = (int)strlen(value->string.language);
		  else
		    n = 0;

	          *bufptr++ = (ipp_uchar_t)(n >> 8);
		  *bufptr++ = (ipp_uchar_t)n;

		  // Language
		  if (n > 0)
		  {
		    memcpy(bufptr, value->string.language, (size_t)n);
		    bufptr += n;
		  }

		  // Length of text
                  if (value->string.text != NULL)
		    n = (int)strlen(value->string.text);
		  else
		    n = 0;

	          *bufptr++ = (ipp_uchar_t)(n >> 8);
		  *bufptr++ = (ipp_uchar_t)n;

		  // Text
		  if (n > 0)
		  {
		    memcpy(bufptr, value->string.text, (size_t)n);
		    bufptr += n;
		  }
		}
		break;

            case IPP_TAG_BEGIN_COLLECTION :
	        for (i = 0, value = attr->values; i < attr->num_values; i ++, value ++)
		{
		  // Collections are written with the begin-collection
		  // tag first with a value of 0 length, followed by the
		  // attributes in the collection, then the end-collection
		  // value...
                  if ((IPP_BUF_SIZE - (bufptr - buffer)) < 5)
		  {
                    if ((*cb)(dst, buffer, (size_t)(bufptr - buffer)) < 0)
	            {
		      DEBUG_puts("1ippWriteIO: Could not write IPP attribute...");
		      _cupsBufferRelease((char *)buffer);
	              return (IPP_STATE_ERROR);
	            }

		    bufptr = buffer;
		  }

		  if (i)
		  {
		    // Arrays and sets are done by sending additional values with a zero-length name...
                    *bufptr++ = (ipp_uchar_t)attr->value_tag;
		    *bufptr++ = 0;
		    *bufptr++ = 0;
		  }

		  // Write a data length of 0 and flush the buffer...
	          *bufptr++ = 0;
		  *bufptr++ = 0;

                  if ((*cb)(dst, buffer, (size_t)(bufptr - buffer)) < 0)
	          {
		    DEBUG_puts("1ippWriteIO: Could not write IPP attribute...");
		    _cupsBufferRelease((char *)buffer);
	            return (IPP_STATE_ERROR);
	          }

		  bufptr = buffer;

		  // Then write the collection attribute...
                  value->collection->state = IPP_STATE_IDLE;

		  if (ippWriteIO(dst, cb, 1, ipp, value->collection) == IPP_STATE_ERROR)
		  {
		    DEBUG_puts("1ippWriteIO: Unable to write collection value");
		    _cupsBufferRelease((char *)buffer);
		    return (IPP_STATE_ERROR);
		  }
		}
		break;

            default :
	        for (i = 0, value = attr->values; i < attr->num_values; i ++, value ++)
		{
		  if (i)
		  {
		    // Arrays and sets are done by sending additional values with a zero-length name...
                    if ((IPP_BUF_SIZE - (bufptr - buffer)) < 3)
		    {
                      if ((*cb)(dst, buffer, (size_t)(bufptr - buffer)) < 0)
	              {
			DEBUG_puts("1ippWriteIO: Could not write IPP attribute...");
			_cupsBufferRelease((char *)buffer);
	        	return (IPP_STATE_ERROR);
	              }

		      bufptr = buffer;
		    }

                    *bufptr++ = (ipp_uchar_t)attr->value_tag;
		    *bufptr++ = 0;
		    *bufptr++ = 0;
		  }

		  // An unknown value might some new value that a
		  // vendor has come up with. It consists of a
		  // 2-byte length and the bytes in the unknown
		  // value buffer.
                  n = value->unknown.length;

                  if (n > (IPP_BUF_SIZE - 2))
		  {
		    DEBUG_printf("1ippWriteIO: Data length too long (%d)", n);
		    _cupsBufferRelease((char *)buffer);
		    return (IPP_STATE_ERROR);
		  }

                  if ((int)(IPP_BUF_SIZE - (bufptr - buffer)) < (n + 2))
		  {
                    if ((*cb)(dst, buffer, (size_t)(bufptr - buffer)) < 0)
	            {
		      DEBUG_puts("1ippWriteIO: Could not write IPP attribute...");
		      _cupsBufferRelease((char *)buffer);
	              return (IPP_STATE_ERROR);
	            }

		    bufptr = buffer;
		  }

		  // Length of unknown value
	          *bufptr++ = (ipp_uchar_t)(n >> 8);
		  *bufptr++ = (ipp_uchar_t)n;

		  // Value
		  if (n > 0)
		  {
		    memcpy(bufptr, value->unknown.data, (size_t)n);
		    bufptr += n;
		  }
		}
		break;
	  }

	  // Write the data out...
	  if (bufptr > buffer)
	  {
	    if ((*cb)(dst, buffer, (size_t)(bufptr - buffer)) < 0)
	    {
	      DEBUG_puts("1ippWriteIO: Could not write IPP attribute...");
	      _cupsBufferRelease((char *)buffer);
	      return (IPP_STATE_ERROR);
	    }

	    DEBUG_printf("2ippWriteIO: wrote %d bytes", (int)(bufptr - buffer));
	  }

          // If blocking is disabled and we aren't at the end of the attribute
          // list, stop here...
          if (!blocking && ipp->current)
	    break;
	}

	if (ipp->current == NULL)
	{
	  // Done with all of the attributes; add the end-of-attributes
	  // tag or end-collection attribute...
          if (parent == NULL)
	  {
            buffer[0] = IPP_TAG_END;
	    n         = 1;
	  }
	  else
	  {
            buffer[0] = IPP_TAG_END_COLLECTION;
	    buffer[1] = 0; // empty name
	    buffer[2] = 0;
	    buffer[3] = 0; // empty value
	    buffer[4] = 0;
	    n         = 5;
	  }

	  if ((*cb)(dst, buffer, (size_t)n) < 0)
	  {
	    DEBUG_puts("1ippWriteIO: Could not write IPP end-tag...");
	    _cupsBufferRelease((char *)buffer);
	    return (IPP_STATE_ERROR);
	  }

	  ipp->state = IPP_STATE_DATA;
	}
        break;

    case IPP_STATE_DATA :
        break;

    default :
        break; // anti-compiler-warning-code
  }

  _cupsBufferRelease((char *)buffer);

  return (ipp->state);
}


//
// 'ipp_add_attr()' - Add a new attribute to the message.
//

static ipp_attribute_t *		// O - New attribute
ipp_add_attr(ipp_t      *ipp,		// I - IPP message
             const char *name,		// I - Attribute name or NULL
             ipp_tag_t  group_tag,	// I - Group tag or IPP_TAG_ZERO
             ipp_tag_t  value_tag,	// I - Value tag or IPP_TAG_ZERO
             size_t     num_values)	// I - Number of values
{
  size_t		alloc_values;	// Number of values to allocate
  ipp_attribute_t	*attr;		// New attribute


  DEBUG_printf("4ipp_add_attr(ipp=%p, name=\"%s\", group_tag=0x%x, value_tag=0x%x, num_values=%u)", (void *)ipp, name, group_tag, value_tag, (unsigned)num_values);

  // Range check input...
  if (!ipp)
    return (NULL);

  // Allocate memory, rounding the allocation up as needed...
  if (num_values <= 1)
    alloc_values = 1;
  else
    alloc_values = (num_values + IPP_MAX_VALUES - 1) & (size_t)~(IPP_MAX_VALUES - 1);

  attr = calloc(1, sizeof(ipp_attribute_t) + (size_t)(alloc_values - 1) * sizeof(_ipp_value_t));

  if (attr)
  {
    // Initialize attribute...
    DEBUG_printf("4debug_alloc: %p %s %s%s (%u values)", (void *)attr, name, num_values > 1 ? "1setOf " : "", ippTagString(value_tag), (unsigned)num_values);

    if (name)
      attr->name = _cupsStrAlloc(name);

    attr->group_tag  = group_tag;
    attr->value_tag  = value_tag;
    attr->num_values = num_values;

    // Add it to the end of the linked list...
    if (ipp->last)
      ipp->last->next = attr;
    else
      ipp->attrs = attr;

    ipp->prev = ipp->last;
    ipp->last = ipp->current = attr;
  }

  DEBUG_printf("5ipp_add_attr: Returning %p", (void *)attr);

  return (attr);
}


//
// 'ipp_free_values()' - Free attribute values.
//

static void
ipp_free_values(ipp_attribute_t *attr,	// I - Attribute to free values from
                size_t          element,// I - First value to free
                size_t          count)	// I - Number of values to free
{
  size_t	i;			// Looping var
  _ipp_value_t	*value;			// Current value


  DEBUG_printf("4ipp_free_values(attr=%p, element=%u, count=%u)", (void *)attr, (unsigned)element, (unsigned)count);

  if (!(attr->value_tag & IPP_TAG_CUPS_CONST))
  {
    // Free values as needed...
    switch (attr->value_tag)
    {
      case IPP_TAG_TEXTLANG :
      case IPP_TAG_NAMELANG :
	  if (element == 0 && count == attr->num_values && attr->values[0].string.language)
	  {
	    _cupsStrFree(attr->values[0].string.language);
	    attr->values[0].string.language = NULL;
	  }
	  // Fall through to other string values

      case IPP_TAG_TEXT :
      case IPP_TAG_NAME :
      case IPP_TAG_RESERVED_STRING :
      case IPP_TAG_KEYWORD :
      case IPP_TAG_URI :
      case IPP_TAG_URISCHEME :
      case IPP_TAG_CHARSET :
      case IPP_TAG_LANGUAGE :
      case IPP_TAG_MIMETYPE :
	  for (i = count, value = attr->values + element; i > 0; i --, value ++)
	  {
	    _cupsStrFree(value->string.text);
	    value->string.text = NULL;
	  }
	  break;

      case IPP_TAG_UNSUPPORTED_VALUE :
      case IPP_TAG_DEFAULT :
      case IPP_TAG_UNKNOWN :
      case IPP_TAG_NOVALUE :
      case IPP_TAG_NOTSETTABLE :
      case IPP_TAG_DELETEATTR :
      case IPP_TAG_ADMINDEFINE :
      case IPP_TAG_INTEGER :
      case IPP_TAG_ENUM :
      case IPP_TAG_BOOLEAN :
      case IPP_TAG_DATE :
      case IPP_TAG_RESOLUTION :
      case IPP_TAG_RANGE :
	  break;

      case IPP_TAG_BEGIN_COLLECTION :
	  for (i = count, value = attr->values + element; i > 0; i --, value ++)
	  {
	    ippDelete(value->collection);
	    value->collection = NULL;
	  }
	  break;

      case IPP_TAG_STRING :
      default :
	  for (i = count, value = attr->values + element; i > 0; i --, value ++)
	  {
	    if (value->unknown.data)
	    {
	      free(value->unknown.data);
	      value->unknown.data = NULL;
	    }
	  }
	  break;
    }
  }

  // If we are not freeing values from the end, move the remaining values up...
  if ((element + count) < attr->num_values)
    memmove(attr->values + element, attr->values + element + count, (size_t)(attr->num_values - count - element) * sizeof(_ipp_value_t));

  attr->num_values -= count;
}


//
// 'ipp_get_code()' - Convert a C locale/charset name into an IPP language/charset code.
//
// This typically converts strings of the form "ll_CC", "ll-REGION", and "CHARSET_NUMBER"
// to "ll-cc", "ll-region", and "charset-number", respectively.
//

static char *				// O - Language code string
ipp_get_code(const char *value,		// I - Locale/charset string
             char       *buffer,	// I - String buffer
             size_t     bufsize)	// I - Size of string buffer
{
  char	*bufptr,			// Pointer into buffer
	*bufend;			// End of buffer


  // Convert values to lowercase and change _ to - as needed...
  for (bufptr = buffer, bufend = buffer + bufsize - 1; *value && bufptr < bufend; value ++)
  {
    if (*value == '_')
      *bufptr++ = '-';
    else
      *bufptr++ = (char)_cups_tolower(*value);
  }
  *bufptr = '\0';

  // Return the converted string...
  return (buffer);
}


//
// 'ipp_is_valid_language()' - Determine whether a language string is valid.
//

static bool				// O - `true` if valid, `false` if bad
ipp_is_valid_language(const char *name,	// I - Attribute name
                      const char *lang)	// I - Language string
{
  if (regexec(&lang_regex, lang, 0, NULL, 0))
  {
    ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad naturalLanguage value \"%s\" - bad characters (RFC 8011 section 5.1.9)."), name, lang);
    return (false);
  }

  if (strlen(lang) > (IPP_MAX_LANGUAGE - 1))
  {
    ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad naturalLanguage value \"%s\" - bad length %d (RFC 8011 section 5.1.9)."), name, lang, (int)strlen(lang));
    return (false);
  }

  return (true);
}


//
// 'ipp_is_valid_mimetype()' - Determine whether a MIME media type string is valid.
//

static bool				// O - `true` if valid, `false` if bad
ipp_is_valid_mimetype(const char *name,	// I - Attribute name
                      const char *type)	// I - mimeMediaType string
{
  if (regexec(&mime_regex, type, 0, NULL, 0))
  {
    ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad mimeMediaType value \"%s\" - bad characters (RFC 8011 section 5.1.10)."), name, type);
    return (false);
  }

  if (strlen(type) > (IPP_MAX_MIMETYPE - 1))
  {
    ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad mimeMediaType value \"%s\" - bad length %d (RFC 8011 section 5.1.10)."), name, type, (int)strlen(type));
    return (false);
  }

  return (true);
}


//
// 'ipp_lang_code()' - Convert a C locale name into an IPP language code.
//
// This typically converts strings of the form "ll_CC" and "ll-REGION" to "ll-cc" and
// "ll-region", respectively.  It also converts the "C" (POSIX) locale to "en".
//

static char *				// O - Language code string
ipp_lang_code(const char *locale,	// I - Locale string
              char       *buffer,	// I - String buffer
              size_t     bufsize)	// I - Size of string buffer
{
  // Map POSIX ("C") locale to generic English, otherwise convert the locale string as-is.
  if (!_cups_strcasecmp(locale, "c"))
  {
    cupsCopyString(buffer, "en", bufsize);
    return (buffer);
  }
  else
  {
    return (ipp_get_code(locale, buffer, bufsize));
  }
}


//
// 'ipp_length()' - Compute the length of an IPP message or collection value.
//

static size_t				// O - Size of IPP message
ipp_length(ipp_t *ipp,			// I - IPP message or collection
           int   collection)		// I - 1 if a collection, 0 otherwise
{
  size_t		i;		// Looping var
  size_t		bytes;		// Number of bytes
  ipp_attribute_t	*attr;		// Current attribute
  ipp_tag_t		group;		// Current group
  _ipp_value_t		*value;		// Current value


  DEBUG_printf("3ipp_length(ipp=%p, collection=%d)", (void *)ipp, collection);

  if (!ipp)
  {
    DEBUG_puts("4ipp_length: Returning 0 bytes");
    return (0);
  }

  // Start with 8 bytes for the IPP message header...
  bytes = collection ? 0 : 8;

  // Then add the lengths of each attribute...
  group = IPP_TAG_ZERO;

  for (attr = ipp->attrs; attr != NULL; attr = attr->next)
  {
    if (attr->group_tag != group && !collection)
    {
      group = attr->group_tag;
      if (group == IPP_TAG_ZERO)
	continue;

      bytes ++;	// Group tag
    }

    if (!attr->name)
      continue;

    DEBUG_printf("5ipp_length: attr->name=\"%s\", attr->num_values=%u, bytes=" CUPS_LLFMT, attr->name, (unsigned)attr->num_values, CUPS_LLCAST bytes);

    if ((attr->value_tag & ~IPP_TAG_CUPS_CONST) < IPP_TAG_EXTENSION)
      bytes += (size_t)attr->num_values;// Value tag for each value
    else
      bytes += (size_t)(5 * attr->num_values);
					// Value tag for each value
    bytes += (size_t)(2 * attr->num_values);
					// Name lengths
    bytes += strlen(attr->name);	// Name
    bytes += (size_t)(2 * attr->num_values);
					// Value lengths

    if (collection)
      bytes += 5;			// Add membername overhead

    switch (attr->value_tag & ~IPP_TAG_CUPS_CONST)
    {
      case IPP_TAG_UNSUPPORTED_VALUE :
      case IPP_TAG_DEFAULT :
      case IPP_TAG_UNKNOWN :
      case IPP_TAG_NOVALUE :
      case IPP_TAG_NOTSETTABLE :
      case IPP_TAG_DELETEATTR :
      case IPP_TAG_ADMINDEFINE :
          break;

      case IPP_TAG_INTEGER :
      case IPP_TAG_ENUM :
          bytes += (size_t)(4 * attr->num_values);
	  break;

      case IPP_TAG_BOOLEAN :
          bytes += (size_t)attr->num_values;
	  break;

      case IPP_TAG_TEXT :
      case IPP_TAG_NAME :
      case IPP_TAG_KEYWORD :
      case IPP_TAG_URI :
      case IPP_TAG_URISCHEME :
      case IPP_TAG_CHARSET :
      case IPP_TAG_LANGUAGE :
      case IPP_TAG_MIMETYPE :
	  for (i = 0, value = attr->values; i < attr->num_values; i ++, value ++)
	  {
	    if (value->string.text)
	      bytes += strlen(value->string.text);
	  }
	  break;

      case IPP_TAG_DATE :
          bytes += (size_t)(11 * attr->num_values);
	  break;

      case IPP_TAG_RESOLUTION :
          bytes += (size_t)(9 * attr->num_values);
	  break;

      case IPP_TAG_RANGE :
          bytes += (size_t)(8 * attr->num_values);
	  break;

      case IPP_TAG_TEXTLANG :
      case IPP_TAG_NAMELANG :
          bytes += (size_t)(4 * attr->num_values);
					// Charset + text length

	  for (i = 0, value = attr->values; i < attr->num_values; i ++, value ++)
	  {
	    if (value->string.language)
	      bytes += strlen(value->string.language);

	    if (value->string.text)
	      bytes += strlen(value->string.text);
	  }
	  break;

      case IPP_TAG_BEGIN_COLLECTION :
	  for (i = 0, value = attr->values; i < attr->num_values; i ++, value ++)
            bytes += ipp_length(value->collection, 1);
	  break;

      default :
	  for (i = 0, value = attr->values; i < attr->num_values; i ++, value ++)
            bytes += (size_t)value->unknown.length;
	  break;
    }
  }

  // Finally, add 1 byte for the "end of attributes" tag or 5 bytes for the "end of collection" tag and return...
  if (collection)
    bytes += 5;
  else
    bytes ++;

  DEBUG_printf("4ipp_length: Returning " CUPS_LLFMT " bytes", CUPS_LLCAST bytes);

  return (bytes);
}


//
// 'ipp_read_file()' - Read IPP data from a file.
//

static ssize_t				// O - Number of bytes read
ipp_read_file(int         *fd,		// I - File descriptor
              ipp_uchar_t *buffer,	// O - Read buffer
	      size_t      length)	// I - Number of bytes to read
{
#ifdef _WIN32
  return ((ssize_t)read(*fd, buffer, (unsigned)length));
#else
  return (read(*fd, buffer, length));
#endif // _WIN32
}


//
// 'ipp_read_http()' - Semi-blocking read on a HTTP connection...
//

static ssize_t				// O - Number of bytes read
ipp_read_http(http_t      *http,	// I - Client connection
              ipp_uchar_t *buffer,	// O - Buffer for data
	      size_t      length)	// I - Total length
{
  ssize_t	tbytes,			// Total bytes read
		bytes;			// Bytes read this pass


  DEBUG_printf("7ipp_read_http(http=%p, buffer=%p, length=%d)", (void *)http, (void *)buffer, (int)length);

  // Loop until all bytes are read...
  for (tbytes = 0, bytes = 0; tbytes < (int)length; tbytes += bytes, buffer += bytes)
  {
    DEBUG_printf("9ipp_read_http: tbytes=" CUPS_LLFMT ", http->state=%d", CUPS_LLCAST tbytes, http->state);

    if (http->state == HTTP_STATE_WAITING)
      break;

    if (http->used == 0 && !http->blocking)
    {
      // Wait up to 10 seconds for more data on non-blocking sockets...
      if (!httpWait(http, 10000))
      {
	// Signal no data...
	bytes = -1;
	break;
      }
    }
    else if (http->used == 0 && http->timeout_value > 0)
    {
      // Wait up to timeout seconds for more data on blocking sockets...
      if (!httpWait(http, (int)(1000 * http->timeout_value)))
      {
	// Signal no data...
	bytes = -1;
	break;
      }
    }

    if ((bytes = httpRead(http, (char *)buffer, length - (size_t)tbytes)) < 0)
    {
#ifdef _WIN32
      break;
#else
      if (errno != EAGAIN && errno != EINTR)
	break;

      bytes = 0;
#endif // _WIN32
    }
    else if (bytes == 0)
    {
      break;
    }
  }

  // Return the number of bytes read...
  if (tbytes == 0 && bytes < 0)
    tbytes = -1;

  DEBUG_printf("8ipp_read_http: Returning " CUPS_LLFMT " bytes", CUPS_LLCAST tbytes);

  return (tbytes);
}


//
// 'ipp_read_io()' - Read data for an IPP message.
//

static ipp_state_t			// O - Current state
ipp_read_io(void        *src,		// I - Data source
            ipp_io_cb_t cb,		// I - Read callback function
	    bool        blocking,	// I - Use blocking IO?
	    ipp_t       *parent,	// I - Parent request, if any
            ipp_t       *ipp,		// I - IPP data
            int         depth)		// I - Depth of collection
{
  int			n;		// Length of data
  unsigned char		*buffer,	// Data buffer
			string[IPP_MAX_TEXT],
					// Small string buffer
			*bufptr,	// Pointer into buffer
			*bufend;	// End of buffer
  ipp_attribute_t	*attr = NULL;	// Current attribute
  ipp_tag_t		tag;		// Current tag
  ipp_tag_t		value_tag;	// Current value tag
  _ipp_value_t		*value;		// Current value


  DEBUG_printf("ipp_read_io(src=%p, cb=%p, blocking=%d, parent=%p, ipp=%p, depth=%d)", (void *)src, (void *)cb, blocking, (void *)parent, (void *)ipp, depth);
  DEBUG_printf("2ipp_read_io: ipp->state=%d", ipp->state);

  if (depth > 10)
  {
    _cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("IPP message nested too deeply."), true);
    return (IPP_STATE_ERROR);
  }

  if ((buffer = (unsigned char *)_cupsBufferGet(IPP_BUF_SIZE)) == NULL)
  {
    DEBUG_puts("1ipp_read_io: Unable to get read buffer.");
    return (IPP_STATE_ERROR);
  }

  switch (ipp->state)
  {
    case IPP_STATE_IDLE :
        ipp->state ++; // Avoid common problem...

    case IPP_STATE_HEADER :
        if (parent == NULL)
	{
          // Get the request header...
          if ((*cb)(src, buffer, 8) < 8)
	  {
	    DEBUG_puts("1ipp_read_io: Unable to read header.");
	    goto rollback;
	  }

          // Then copy the request header over...
          ipp->request.version[0]  = buffer[0];
          ipp->request.version[1]  = buffer[1];
          ipp->request.op_status   = (short)((buffer[2] << 8) | buffer[3]);
          ipp->request.request_id  = (buffer[4] << 24) | (buffer[5] << 16) | (buffer[6] << 8) | buffer[7];

          DEBUG_printf("2ipp_read_io: version=%d.%d", buffer[0], buffer[1]);
	  DEBUG_printf("2ipp_read_io: op_status=%04x", ipp->request.op_status);
	  DEBUG_printf("2ipp_read_io: request_id=%d", ipp->request.request_id);
        }

        ipp->state   = IPP_STATE_ATTRIBUTE;
	ipp->current = NULL;
	ipp->curtag  = IPP_TAG_ZERO;
	ipp->prev    = ipp->last;

        // If blocking is disabled, stop here...
        if (!blocking)
	  break;

    case IPP_STATE_ATTRIBUTE :
        for (;;)
	{
	  if ((*cb)(src, buffer, 1) < 1)
	  {
	    DEBUG_puts("1ipp_read_io: Callback returned EOF/error");
	    goto rollback;
	  }

	  DEBUG_printf("2ipp_read_io: ipp->current=%p, ipp->prev=%p", (void *)ipp->current, (void *)ipp->prev);

	  // Read this attribute...
          tag = (ipp_tag_t)buffer[0];

	  if (tag == IPP_TAG_END)
	  {
	    // No more attributes left...
            DEBUG_puts("2ipp_read_io: IPP_TAG_END.");

	    ipp->state = IPP_STATE_DATA;
	    break;
	  }
	  else if (tag == IPP_TAG_ZERO || (tag == IPP_TAG_OPERATION && ipp->curtag != IPP_TAG_ZERO))
	  {
	    _cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("Invalid group tag."), true);
	    DEBUG_printf("1ipp_read_io: bad tag 0x%02x.", tag);
	    goto rollback;
	  }
          else if (tag < IPP_TAG_UNSUPPORTED_VALUE)
	  {
	    // Group tag...  Set the current group and continue...
            if (parent)
            {
	      _cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("Invalid group tag."), true);
	      DEBUG_printf("1ipp_read_io: bad tag 0x%02x.", tag);
	      goto rollback;
            }
            else if (ipp->curtag == tag)
            {
	      ipp->prev = ippAddSeparator(ipp);
            }
            else if (ipp->current)
	    {
	      ipp->prev = ipp->current;
	    }

	    ipp->curtag  = tag;
	    ipp->current = NULL;
	    attr         = NULL;
	    DEBUG_printf("2ipp_read_io: group tag=%x(%s), ipp->prev=%p", tag, ippTagString(tag), (void *)ipp->prev);
	    continue;
	  }

          DEBUG_printf("2ipp_read_io: value tag=%x(%s)", tag, ippTagString(tag));

	  // Get the name...
          if ((*cb)(src, buffer, 2) < 2)
	  {
	    DEBUG_puts("1ipp_read_io: unable to read name length.");
	    goto rollback;
	  }

          n = (buffer[0] << 8) | buffer[1];

          if (n >= IPP_BUF_SIZE)
	  {
	    _cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("IPP name larger than 32767 bytes."), true);
	    DEBUG_printf("1ipp_read_io: bad name length %d.", n);
	    goto rollback;
	  }

          DEBUG_printf("2ipp_read_io: name length=%d", n);

          if (n && parent)
          {
            _cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("Invalid named IPP attribute in collection."), true);
            DEBUG_puts("1ipp_read_io: bad attribute name in collection.");
	    goto rollback;
          }
          else if (n == 0 && tag != IPP_TAG_MEMBERNAME && tag != IPP_TAG_END_COLLECTION)
	  {
	    // More values for current attribute...
            if (ipp->current == NULL)
	    {
	      _cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("IPP attribute has no name."), true);
	      DEBUG_puts("1ipp_read_io: Attribute without name and no current.");
	      goto rollback;
	    }

            attr      = ipp->current;
	    value_tag = (ipp_tag_t)(attr->value_tag & IPP_TAG_CUPS_MASK);

	    // Make sure we aren't adding a new value of a different type...
	    if (value_tag == IPP_TAG_ZERO)
	    {
	      // Setting the value of a collection member...
	      attr->value_tag = tag;
	    }
	    else if (value_tag == IPP_TAG_TEXTLANG || value_tag == IPP_TAG_NAMELANG || (value_tag >= IPP_TAG_TEXT && value_tag <= IPP_TAG_MIMETYPE))
            {
	      // String values can sometimes come across in different forms; accept sets of differing values...
	      if (tag != IPP_TAG_TEXTLANG && tag != IPP_TAG_NAMELANG && (tag < IPP_TAG_TEXT || tag > IPP_TAG_MIMETYPE) && tag != IPP_TAG_NOVALUE)
	      {
		_cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("IPP 1setOf attribute with incompatible value tags."), true);
		DEBUG_printf("1ipp_read_io: 1setOf value tag %x(%s) != %x(%s)", value_tag, ippTagString(value_tag), tag, ippTagString(tag));
		goto rollback;
	      }

              if (value_tag != tag)
              {
                DEBUG_printf("1ipp_read_io: Converting %s attribute from %s to %s.", attr->name, ippTagString(value_tag), ippTagString(tag));
		if (!ippSetValueTag(ipp, &attr, tag))
		  goto rollback;
	      }
            }
	    else if (value_tag == IPP_TAG_INTEGER || value_tag == IPP_TAG_RANGE)
            {
	      // Integer and rangeOfInteger values can sometimes be mixed; accept sets of differing values...
	      if (tag != IPP_TAG_INTEGER && tag != IPP_TAG_RANGE)
	      {
		_cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("IPP 1setOf attribute with incompatible value tags."), true);
		DEBUG_printf("1ipp_read_io: 1setOf value tag %x(%s) != %x(%s)", value_tag, ippTagString(value_tag), tag, ippTagString(tag));
		goto rollback;
	      }

              if (value_tag == IPP_TAG_INTEGER && tag == IPP_TAG_RANGE)
              {
                // Convert integer values to rangeOfInteger values...
		DEBUG_printf("1ipp_read_io: Converting %s attribute to rangeOfInteger.", attr->name);
                ippSetValueTag(ipp, &attr, IPP_TAG_RANGE);
              }
            }
	    else if (value_tag != tag)
	    {
	      _cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("IPP 1setOf attribute with incompatible value tags."), true);
	      DEBUG_printf("1ipp_read_io: value tag %x(%s) != %x(%s)", value_tag, ippTagString(value_tag), tag, ippTagString(tag));
	      goto rollback;
            }

	    // Finally, reallocate the attribute array as needed...
	    if ((value = ipp_set_value(ipp, &attr, attr->num_values)) == NULL)
	      goto rollback;
	  }
	  else if (tag == IPP_TAG_MEMBERNAME)
	  {
	    // Name must be length 0!
	    if (n)
	    {
	      _cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("IPP member name is not empty."), true);
	      DEBUG_puts("1ipp_read_io: member name not empty.");
	      goto rollback;
	    }
	    else if (!parent)
	    {
	      _cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("IPP member attribute outside of collection."), true);
	      DEBUG_puts("1ipp_read_io: member attribute outside of collection.");
	      goto rollback;
	    }

            if (ipp->current)
	      ipp->prev = ipp->current;

	    attr = ipp->current = ipp_add_attr(ipp, NULL, ipp->curtag, IPP_TAG_ZERO, 1);
	    if (!attr)
	    {
	      _cupsSetError(IPP_STATUS_ERROR_INTERNAL, strerror(errno), false);
	      DEBUG_puts("1ipp_read_io: unable to allocate attribute.");
	      goto rollback;
	    }

	    DEBUG_printf("2ipp_read_io: membername, ipp->current=%p, ipp->prev=%p", (void *)ipp->current, (void *)ipp->prev);

	    value = attr->values;
	  }
	  else if (tag != IPP_TAG_END_COLLECTION)
	  {
	    // New attribute; read the name and add it...
	    if ((*cb)(src, buffer, (size_t)n) < n)
	    {
	      _cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("Unable to read IPP attribute name."), true);
	      DEBUG_puts("1ipp_read_io: unable to read name.");
	      goto rollback;
	    }

	    buffer[n] = '\0';

            if (ipp->current)
	      ipp->prev = ipp->current;

	    if ((attr = ipp->current = ipp_add_attr(ipp, (char *)buffer, ipp->curtag, tag, 1)) == NULL)
	    {
	      _cupsSetError(IPP_STATUS_ERROR_INTERNAL, strerror(errno), false);
	      DEBUG_puts("1ipp_read_io: unable to allocate attribute.");
	      goto rollback;
	    }

	    DEBUG_printf("2ipp_read_io: name=\"%s\", ipp->current=%p, ipp->prev=%p", buffer, (void *)ipp->current, (void *)ipp->prev);

	    value = attr->values;
	  }
	  else
	  {
	    attr  = NULL;
	    value = NULL;
	  }

	  if ((*cb)(src, buffer, 2) < 2)
	  {
	    DEBUG_puts("1ipp_read_io: unable to read value length.");
	    goto rollback;
	  }

	  n = (buffer[0] << 8) | buffer[1];
          DEBUG_printf("2ipp_read_io: value length=%d", n);

	  if (n >= IPP_BUF_SIZE)
	  {
	    _cupsSetError(IPP_STATUS_ERROR_INTERNAL,
			  _("IPP value larger than 32767 bytes."), true);
	    DEBUG_printf("1ipp_read_io: bad value length %d.", n);
	    goto rollback;
	  }

	  switch (tag)
	  {
	    case IPP_TAG_INTEGER :
	    case IPP_TAG_ENUM :
		if (n != 4)
		{
		  if (tag == IPP_TAG_INTEGER)
		    _cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("IPP integer value not 4 bytes."), true);
		  else
		    _cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("IPP enum value not 4 bytes."), true);
		  DEBUG_printf("1ipp_read_io: bad integer value length %d.", n);
		  goto rollback;
		}

	        if ((*cb)(src, buffer, 4) < 4)
		{
	          DEBUG_puts("1ipp_read_io: Unable to read integer value.");
		  goto rollback;
		}

		n = (buffer[0] << 24) | (buffer[1] << 16) | (buffer[2] << 8) | buffer[3];

                if (attr->value_tag == IPP_TAG_RANGE)
                  value->range.lower = value->range.upper = n;
                else
		  value->integer = n;
	        break;

	    case IPP_TAG_BOOLEAN :
		if (n != 1)
		{
		  _cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("IPP boolean value not 1 byte."),
		                1);
		  DEBUG_printf("1ipp_read_io: bad boolean value length %d.", n);
		  goto rollback;
		}

	        if ((*cb)(src, buffer, 1) < 1)
		{
	          DEBUG_puts("1ipp_read_io: Unable to read boolean value.");
		  goto rollback;
		}

                value->boolean = (char)buffer[0];
	        break;

	    case IPP_TAG_UNSUPPORTED_VALUE :
	    case IPP_TAG_DEFAULT :
	    case IPP_TAG_UNKNOWN :
	    case IPP_TAG_NOVALUE :
	    case IPP_TAG_NOTSETTABLE :
	    case IPP_TAG_DELETEATTR :
	    case IPP_TAG_ADMINDEFINE :
	        // These value types are not supposed to have values, however
		// some vendors (Brother) do not implement IPP correctly and so
		// we need to map non-empty values to text...
	        if (attr->value_tag == tag)
		{
		  if (n == 0)
		    break;

		  attr->value_tag = IPP_TAG_TEXT;
		}

	    case IPP_TAG_TEXT :
	    case IPP_TAG_NAME :
	    case IPP_TAG_RESERVED_STRING :
	    case IPP_TAG_KEYWORD :
	    case IPP_TAG_URI :
	    case IPP_TAG_URISCHEME :
	    case IPP_TAG_CHARSET :
	    case IPP_TAG_LANGUAGE :
	    case IPP_TAG_MIMETYPE :
	        if (n > 0)
	        {
		  if ((*cb)(src, buffer, (size_t)n) < n)
		  {
		    DEBUG_puts("1ipp_read_io: unable to read string value.");
		    goto rollback;
		  }
		}

		buffer[n] = '\0';
		value->string.text = _cupsStrAlloc((char *)buffer);
		DEBUG_printf("2ipp_read_io: value=\"%s\"(%p)", value->string.text, value->string.text);
	        break;

	    case IPP_TAG_DATE :
		if (n != 11)
		{
		  _cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("IPP date value not 11 bytes."), true);
		  DEBUG_printf("1ipp_read_io: bad date value length %d.", n);
		  goto rollback;
		}

	        if ((*cb)(src, value->date, 11) < 11)
		{
	          DEBUG_puts("1ipp_read_io: Unable to read date value.");
		  goto rollback;
		}
	        break;

	    case IPP_TAG_RESOLUTION :
		if (n != 9)
		{
		  _cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("IPP resolution value not 9 bytes."), true);
		  DEBUG_printf("1ipp_read_io: bad resolution value length %d.", n);
		  goto rollback;
		}

	        if ((*cb)(src, buffer, 9) < 9)
		{
	          DEBUG_puts("1ipp_read_io: Unable to read resolution value.");
		  goto rollback;
		}

                value->resolution.xres  = (buffer[0] << 24) | (buffer[1] << 16) | (buffer[2] << 8) | buffer[3];
                value->resolution.yres  = (buffer[4] << 24) | (buffer[5] << 16) | (buffer[6] << 8) | buffer[7];
                value->resolution.units =
		    (ipp_res_t)buffer[8];
	        break;

	    case IPP_TAG_RANGE :
		if (n != 8)
		{
		  _cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("IPP rangeOfInteger value not 8 bytes."), true);
		  DEBUG_printf("1ipp_read_io: bad rangeOfInteger value length %d.", n);
		  goto rollback;
		}

	        if ((*cb)(src, buffer, 8) < 8)
		{
	          DEBUG_puts("1ipp_read_io: Unable to read range value.");
		  goto rollback;
		}

                value->range.lower = (buffer[0] << 24) | (buffer[1] << 16) | (buffer[2] << 8) | buffer[3];
                value->range.upper = (buffer[4] << 24) | (buffer[5] << 16) | (buffer[6] << 8) | buffer[7];
	        break;

	    case IPP_TAG_TEXTLANG :
	    case IPP_TAG_NAMELANG :
	        if (n < 4)
		{
		  if (tag == IPP_TAG_TEXTLANG)
		    _cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("IPP textWithLanguage value less than minimum 4 bytes."), true);
		  else
		    _cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("IPP nameWithLanguage value less than minimum 4 bytes."), true);
		  DEBUG_printf("1ipp_read_io: bad stringWithLanguage value length %d.", n);
		  goto rollback;
		}

	        if ((*cb)(src, buffer, (size_t)n) < n)
		{
	          DEBUG_puts("1ipp_read_io: Unable to read string w/language value.");
		  goto rollback;
		}

                bufptr = buffer;
                bufend = buffer + n;

	        // textWithLanguage and nameWithLanguage are composite values:
		//
		//   language-length
		//   language
		//   text-length
		//   text
		n = (bufptr[0] << 8) | bufptr[1];

		if ((bufptr + 2 + n + 2) > bufend || n >= (int)sizeof(string))
		{
		  _cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("IPP language length overflows value."), true);
		  DEBUG_printf("1ipp_read_io: bad language value length %d.", n);
		  goto rollback;
		}
		else if (n >= IPP_MAX_LANGUAGE)
		{
		  _cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("IPP language length too large."), true);
		  DEBUG_printf("1ipp_read_io: bad language value length %d.", n);
		  goto rollback;
		}

		memcpy(string, bufptr + 2, (size_t)n);
		string[n] = '\0';

		value->string.language = _cupsStrAlloc((char *)string);

                bufptr += 2 + n;
		n = (bufptr[0] << 8) | bufptr[1];

		if ((bufptr + 2 + n) > bufend)
		{
		  _cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("IPP string length overflows value."), true);
		  DEBUG_printf("1ipp_read_io: bad string value length %d.", n);
		  goto rollback;
		}

		bufptr[2 + n] = '\0';
                value->string.text = _cupsStrAlloc((char *)bufptr + 2);
	        break;

            case IPP_TAG_BEGIN_COLLECTION :
	        // Oh boy, here comes a collection value, so read it...
                value->collection = ippNew();

                if (n > 0)
		{
		  _cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("IPP begCollection value not 0 bytes."), true);
	          DEBUG_puts("1ipp_read_io: begCollection tag with value length > 0.");
		  goto rollback;
		}

		if (ipp_read_io(src, cb, 1, ipp, value->collection, depth + 1) == IPP_STATE_ERROR)
		{
	          DEBUG_puts("1ipp_read_io: Unable to read collection value.");
		  goto rollback;
		}
                break;

            case IPP_TAG_END_COLLECTION :
                if (n > 0)
		{
		  _cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("IPP endCollection value not 0 bytes."), true);
	          DEBUG_puts("1ipp_read_io: endCollection tag with value length > 0.");
		  goto rollback;
		}

		_cupsBufferRelease((char *)buffer);

	        DEBUG_puts("1ipp_read_io: endCollection tag...");
		return (ipp->state = IPP_STATE_DATA);

            case IPP_TAG_MEMBERNAME :
	        // The value is the name of the member in the collection, which
		// we need to carry over...
		if (n == 0)
		{
		  _cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("IPP memberName value is empty."), true);
	          DEBUG_puts("1ipp_read_io: Empty member name value.");
		  goto rollback;
		}
		else if ((*cb)(src, buffer, (size_t)n) < n)
		{
	          DEBUG_puts("1ipp_read_io: Unable to read member name value.");
		  goto rollback;
		}

		buffer[n] = '\0';
		attr->name = _cupsStrAlloc((char *)buffer);

	        // Since collection members are encoded differently than
		// regular attributes, make sure we don't start with an
		// empty value...
                attr->num_values --;

		DEBUG_printf("2ipp_read_io: member name=\"%s\"", attr->name);
		break;

            case IPP_TAG_STRING :
            default : // Other unsupported values
                if (tag == IPP_TAG_STRING && n > IPP_MAX_LENGTH)
		{
		  _cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("IPP octetString length too large."), true);
		  DEBUG_printf("1ipp_read_io: bad octetString value length %d.", n);
		  goto rollback;
		}

                value->unknown.length = (size_t)n;

	        if (n > 0)
		{
		  if ((value->unknown.data = malloc((size_t)n)) == NULL)
		  {
		    _cupsSetError(IPP_STATUS_ERROR_INTERNAL, strerror(errno), false);
		    DEBUG_puts("1ipp_read_io: Unable to allocate value");
		    goto rollback;
		  }

	          if ((*cb)(src, value->unknown.data, (size_t)n) < n)
		  {
	            DEBUG_puts("1ipp_read_io: Unable to read unsupported value.");
		    goto rollback;
		  }
		}
		else
		{
		  value->unknown.data = NULL;
		}
	        break;
	  }

          // If blocking is disabled, stop here...
          if (!blocking)
	    break;
	}
        break;

    case IPP_STATE_DATA :
        break;

    default :
        break; // anti-compiler-warning-code
  }

  DEBUG_printf("1ipp_read_io: returning ipp->state=%d.", ipp->state);
  _cupsBufferRelease((char *)buffer);

  return (ipp->state);

  // If we get here, there was an error that required us to roll back the last
  // attribute read in order to keep the IPP message valid...
  rollback:

  DEBUG_puts("1ipp_read_io: <<rollback>>");

  _cupsBufferRelease((char *)buffer);

  if (attr)
    ippDeleteAttribute(ipp, attr);

  return (IPP_STATE_ERROR);
}


//
// 'ipp_regex_begin()' - Start using validation regular expressions.
//

static bool				// O - `true` on success, `false` on failure
ipp_regex_begin(void)
{
  int		r;			// regcomp() error code


  // Take a lock...
  cupsMutexLock(&regex_mutex);

  // If the regular expressions have not been initialized, do so now...
  if (!regex_init)
  {
    regex_init = true;

    // The following regular expression is derived from the ABNF for
    // language tags in RFC 4646.  All I can say is that this is the
    // easiest way to check the values...
    if ((r = regcomp(&lang_regex,
		     "^("
		     "(([a-z]{2,3}(-[a-z][a-z][a-z]){0,3})|[a-z]{4,8})"
							// language
		     "(-[a-z][a-z][a-z][a-z]){0,1}"	// script
		     "(-([a-z][a-z]|[0-9][0-9][0-9])){0,1}"
							// region
		     "(-([a-z]{5,8}|[0-9][0-9][0-9]))*"	// variant
		     "(-[a-wy-z](-[a-z0-9]{2,8})+)*"	// extension
		     "(-x(-[a-z0-9]{1,8})+)*"		// privateuse
		     "|"
		     "x(-[a-z0-9]{1,8})+"		// privateuse
		     "|"
		     "[a-z]{1,3}(-[a-z][0-9]{2,8}){1,2}"// grandfathered
		     ")$",
		     REG_NOSUB | REG_EXTENDED)) != 0)
    {
      char	temp[256];		// Temporary error string

      regerror(r, &lang_regex, temp, sizeof(temp));
      ipp_set_error(IPP_STATUS_ERROR_INTERNAL, _("Unable to compile naturalLanguage regular expression: %s."), temp);
      cupsMutexUnlock(&regex_mutex);
      return (false);
    }


    // The following regular expression is derived from the ABNF for
    // MIME media types in RFC 2045 and 4288.  All I can say is that this is
    // the easiest way to check the values...
    if ((r = regcomp(&mime_regex,
		     "^"
		     "[-a-zA-Z0-9!#$&.+^_]{1,127}"	// type-name
		     "/"
		     "[-a-zA-Z0-9!#$&.+^_]{1,127}"	// subtype-name
		     "(;[-a-zA-Z0-9!#$&.+^_]{1,127}="	// argument=
		     "([-a-zA-Z0-9!#$&.+^_]{1,127}|\"[^\"]*\"))*"
							// value
		     "$",
		     REG_NOSUB | REG_EXTENDED)) != 0)
    {
      char	temp[256];		// Temporary error string

      regerror(r, &mime_regex, temp, sizeof(temp));
      ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("Unable to compile mimeMediaType regular expression: %s."), temp);
      cupsMutexUnlock(&regex_mutex);
      return (false);
    }
  }

  return (true);
}


//
// 'ipp_regex_end()' - Finish using validation regular expressions.
//

static void
ipp_regex_end(void)
{
  cupsMutexUnlock(&regex_mutex);
}


//
// 'ipp_set_error()' - Set a formatted, localized error string.
//

static void
ipp_set_error(ipp_status_t status,	// I - Status code
              const char   *format,	// I - Printf-style error string
	      ...)			// I - Additional arguments as needed
{
  va_list	ap;			// Pointer to additional args
  char		buffer[2048];		// Message buffer
  cups_lang_t	*lang = cupsLangDefault();
					// Current language


  va_start(ap, format);
  vsnprintf(buffer, sizeof(buffer), cupsLangGetString(lang, format), ap);
  va_end(ap);

  _cupsSetError(status, buffer, 0);
}


//
// 'ipp_set_value()' - Get the value element from an attribute, expanding it as
//                     needed.
//

static _ipp_value_t *			// O  - IPP value element or NULL on error
ipp_set_value(ipp_t           *ipp,	// IO - IPP message
              ipp_attribute_t **attr,	// IO - IPP attribute
              size_t          element)	// I  - Value number (`0`-based)
{
  ipp_attribute_t	*temp,		// New attribute pointer
			*current,	// Current attribute in list
			*prev;		// Previous attribute in list
  size_t		alloc_values;	// Allocated values


  // If we are setting an existing value element, return it...
  temp = *attr;

  if (temp->num_values <= 1)
    alloc_values = 1;
  else
    alloc_values = (temp->num_values + IPP_MAX_VALUES - 1) & (size_t)~(IPP_MAX_VALUES - 1);

  if (element < alloc_values)
  {
    if (element >= temp->num_values)
      temp->num_values = element + 1;

    return (temp->values + element);
  }

  // Otherwise re-allocate the attribute - we allocate in groups of
  // IPP_MAX_VALUE values when num_values > 1.
  if (alloc_values < IPP_MAX_VALUES)
    alloc_values = IPP_MAX_VALUES;
  else
    alloc_values += IPP_MAX_VALUES;

  DEBUG_printf("4ipp_set_value: Reallocating for up to %u values.", (unsigned)alloc_values);

  // Reallocate memory...
  if ((temp = realloc(temp, sizeof(ipp_attribute_t) + (size_t)(alloc_values - 1) * sizeof(_ipp_value_t))) == NULL)
  {
    _cupsSetError(IPP_STATUS_ERROR_INTERNAL, strerror(errno), false);
    DEBUG_puts("4ipp_set_value: Unable to resize attribute.");
    return (NULL);
  }

  // Zero the new memory...
  memset(temp->values + temp->num_values, 0, (size_t)(alloc_values - temp->num_values) * sizeof(_ipp_value_t));

  if (temp != *attr)
  {
    // Reset pointers in the list...
#ifndef __clang_analyzer__
    DEBUG_printf("4debug_free: %p %s", (void *)*attr, temp->name);
#endif // !__clang_analyzer__
    DEBUG_printf("4debug_alloc: %p %s %s%s (%u)", (void *)temp, temp->name, temp->num_values > 1 ? "1setOf " : "", ippTagString(temp->value_tag), (unsigned)temp->num_values);

    if (ipp->current == *attr && ipp->prev && ipp->prev->next == *attr)
    {
      // Use current "previous" pointer...
      prev = ipp->prev;
    }
    else
    {
      // Find this attribute in the linked list...
      for (prev = NULL, current = ipp->attrs; current && current != *attr; prev = current, current = current->next)
        ;				// Loop until we find the attribute

      if (!current)
      {
	// This is a serious error!
	*attr = temp;
	_cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("IPP attribute is not a member of the message."), true);
	DEBUG_puts("4ipp_set_value: Unable to find attribute in message.");
	return (NULL);
      }
    }

    if (prev)
      prev->next = temp;
    else
      ipp->attrs = temp;

    ipp->current = temp;
    ipp->prev    = prev;

    if (ipp->last == *attr)
      ipp->last = temp;

    *attr = temp;
  }

  // Return the value element...
  if (element >= temp->num_values)
    temp->num_values = element + 1;

  return (temp->values + element);
}


//
// 'ipp_write_file()' - Write IPP data to a file.
//

static ssize_t				// O - Number of bytes written
ipp_write_file(int         *fd,		// I - File descriptor
               ipp_uchar_t *buffer,	// I - Data to write
               size_t      length)	// I - Number of bytes to write
{
#ifdef _WIN32
  return ((ssize_t)write(*fd, buffer, (unsigned)length));
#else
  return (write(*fd, buffer, length));
#endif // _WIN32
}
