sip_pref_util.c

Sofia SIP is an open-source SIP User-Agent library, compliant with the IETF RFC3261 specification.

/*
 * This file is part of the Sofia-SIP package
 *
 * Copyright (C) 2005 Nokia Corporation.
 *
 * Contact: Pekka Pessi <[e-mail]>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License
 * as published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA
 *
 */

/**@CFILE sip_pref_util.c
 * 
 * SIP callercaps and callerprefs utility functions.
 *
 * @author Pekka Pessi <[e-mail]>.
 *
 * @date Created: Tue Nov  2 16:39:33 EET 2004 ppessi
 */

#include "config.h"

#include <stdio.h>
#include <stddef.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <float.h>

#include "sofia-sip/sip_parser.h"
#include <sofia-sip/sip_header.h>
#include <sofia-sip/sip_util.h>
#include <sofia-sip/sip_status.h>

static double parse_number(char const *str, char **return_end);

/** Parse a single preference */
int sip_prefs_parse(union sip_pref *sp, 
		    char const **in_out_s, 
		    int *return_negation)
{
  char const *s;
  size_t n;
  enum sp_type old_type;

  assert(sp && in_out_s && *in_out_s && return_negation);

  old_type = sp->sp_type;
  sp->sp_type = sp_error;

  s = *in_out_s;
  if (!s)
    return 0;

  if (old_type == sp_init) {
    if (s[0] == '\0' || 
	strcasecmp(s, "TRUE") == 0 ||
	strcasecmp(s, "\"TRUE\"") == 0) {
      /* Boolean */
      sp->sp_type = sp_literal;
      sp->sp_literal.spl_value = "TRUE";
      sp->sp_literal.spl_length = 4;
      *return_negation = 0;
      *in_out_s = s + strlen(s);
      return 1;
    } else if (strcasecmp(s, "FALSE") == 0 || 
	       strcasecmp(s, "\"FALSE\"") == 0) {
      /* Boolean */
      sp->sp_type = sp_literal;
      sp->sp_literal.spl_value = "FALSE";
      sp->sp_literal.spl_length = 5;
      *return_negation = 0;
      *in_out_s = s + strlen(s);
      return 1;
    } else if (s[0] == '"' && s[1] != '\0') {
      for (s++; IS_LWS(s[0]); s++);
    } else
      old_type = sp_error;      
  } else if (!s[0]) {
    sp->sp_type = sp_init;
    return 0;
  }

  if (old_type == sp_error)
    return 0;

  if ((*return_negation = s[0] == '!'))
      for (s++; IS_LWS(s[0]); s++);

  if (*s == '#') {
    /* Numeric */
    double n1, n2;
    char s0, *e;

    for (s++; IS_LWS(s[0]); s++);
    
    s0 = s[0];

    if (s0 == '=')
      sp->sp_type = sp_range, n1 = n2 = parse_number(s = s + 1, &e);
    else if (s0 == '<' && s[1] == '=')
      sp->sp_type = sp_range, n1 = -DBL_MAX, n2 = parse_number(s = s + 2, &e);
    else if (s0 == '>' && s[1] == '=')
      sp->sp_type = sp_range, n1 = parse_number(s = s + 2, &e), n2 = DBL_MAX;
    else if (((n1 = parse_number(s, &e)) != 0.0 || s != e) && e[0] == ':')
      sp->sp_type = sp_range, n2 = parse_number(s = e + 1, &e);
    else
      /* Error in conversion */
      sp->sp_type = sp_error, n1 = DBL_MAX, n2 = -DBL_MAX;

    if (s == e && (n1 == 0.0 || n2 == 0.0))
      sp->sp_type = sp_error;      /* Error in conversion */

    sp->sp_range.spr_lower = n1;
    sp->sp_range.spr_upper = n2;

    s = e;
  } else if (*s == '<') {
    /* Quoted string */
    n = strcspn(++s, ">");
    sp->sp_type = sp_string;
    sp->sp_string.sps_value = s;
    sp->sp_string.sps_length = n;
    s += n + 1;
  } else if ((n = span_token(s))) {
    /* Literal */
    sp->sp_type = sp_literal;
    sp->sp_literal.spl_value = s;
    sp->sp_literal.spl_length = n;
    s += n;
  }

  for (; IS_LWS(s[0]); s++);

  if (s[0] == ',' || (s[0] == '"' && s[1] == '\0'))
    for (s++; IS_LWS(s[0]); s++);
  else
    old_type = sp_error;

  if (old_type != sp_init && old_type != sp->sp_type) 
    sp->sp_type = sp_error;
    
  *in_out_s = s;

  return sp->sp_type != sp_error;
}

/** Parse number:
 * number          =  [ "+" / "-" ] 1*DIGIT ["." 0*DIGIT]
 */
static double parse_number(char const *str, char **return_end)
{
  double value = 0.0;
  double decimal = 0.1;
  char d, sign = '+';

  if (return_end)
    *return_end = (char *)str;

  d = *str;

  if (d == '+' || d == '-')
    sign = d, d = *++str;

  if (!('0' <= d && d <= '9'))
    return value;

  for (; '0' <= d && d <= '9'; d = *++str)
    value = value * 10 + (d - '0');

  if (d == '.') for (d = *++str; '0' <= d && d <= '9'; d = *++str) {
    value += (d - '0') * decimal; decimal *= 0.1;
  }

  if (value > DBL_MAX)
    value = DBL_MAX;

  if (sign == '-')
    value = -value;

  if (return_end)
    *return_end = (char *)str;

  return value;
}


/** Return true if preferences match */
int sip_prefs_match(union sip_pref const *a, 
		    union sip_pref const *b)
{
  if (!a || !b)
    return 0;
  if (a->sp_type != b->sp_type)
    return 0;
  switch (a->sp_type) {
  default:
  case sp_error: 
    return 0;
  case sp_literal:
    return 
      a->sp_literal.spl_length == b->sp_literal.spl_length &&
      strncasecmp(a->sp_literal.spl_value, b->sp_literal.spl_value,
		  a->sp_literal.spl_length) == 0;
  case sp_string:
    return 
      a->sp_string.sps_length == b->sp_string.sps_length &&
      strncmp(a->sp_string.sps_value, b->sp_string.sps_value,
	      a->sp_string.sps_length) == 0;
  case sp_range:
    return 
      a->sp_range.spr_lower <= b->sp_range.spr_upper &&
      a->sp_range.spr_upper >= b->sp_range.spr_lower;
  }
}

/**Find a matching parameter-value pair from a parameter list.
 *
 * Check if the given feature values match with each other.
 *
 * @param pvalue first feature parameter
 * @param nvalue second feature parameter
 * @param return_parse_error return-value parameter for error (may be NULL)
 *
 * @retval 1 if given feature parameters match
 * @retval 0 if there is no match or a parse or type error occurred.
 *
 * If there is a parsing or type error, 0 is returned and @a
 * *return_parse_error is set to -1.
 *
 * @sa sip_prefs_parse(), sip_prefs_match(), union #sip_pref.
 */
int sip_prefs_matching(char const *pvalue,
		       char const *nvalue,
		       int *return_parse_error)
{
  int error;
  char const *p;
  union sip_pref np[1], pp[1];
  int n_negated, p_negated;

  if (!return_parse_error)
    return_parse_error = &error;

  if (!pvalue || !nvalue)
    return 0;

  memset(np, 0, sizeof np);

  /* Usually nvalue is from Accept/Reject-Contact, 
     pvalue is from Contact */
  while (sip_prefs_parse(np, &nvalue, &n_negated)) {
    memset(pp, 0, sizeof pp);
    p = pvalue;

    while (sip_prefs_parse(pp, &p, &p_negated)) {
      if (pp->sp_type != np->sp_type) /* Types do not match */
	return 0;

      if (sip_prefs_match(np, pp) /* We found matching value */
	  ? !p_negated	/* without negative */
	  : p_negated)	/* Negative did not match */
	break;
    }

    if (pp->sp_type == sp_error)
      return *return_parse_error = -1, 0;

    if (pp->sp_type != sp_init /* We found matching value */
	? !n_negated		/* and we expected one */
	: n_negated)		/* We found none and expected none */
      return 1;
  }

  if (np->sp_type == sp_error)
    *return_parse_error = -1;

  return 0;
}

/** Check if the parameter is a valid feature tag. 
 *
 * A feature tag is a parameter starting with a single plus, or a well-known
 * feature tag listed in @RFC3841: "audio", "automata", "application",
 * "class", "control", "duplex", "data", "description", "events", "isfocus",
 * "language", "mobility", "methods", "priority", "schemes", "type", or
 * "video". However, well-known feature tag can not start with plus. So,
 * "+alarm" or "audio" is a feature tag, "alarm", "++alarm", or "+audio" are
 * not.