forked from osmocom/wireshark
![Michael Mann](/assets/img/avatar_default.png)
All current uses of ws_find_media_type_parameter need wmem_packet_scope(), but there is no sense in limiting what other dissectors may want to do. Change-Id: I35b0dd2a024a0ae0a8345577dd92a1a21ddd2cc4 Reviewed-on: https://code.wireshark.org/review/26427 Petri-Dish: Michael Mann <mmann78@netscape.net> Tested-by: Petri Dish Buildbot Reviewed-by: Michael Mann <mmann78@netscape.net>
229 lines
6.8 KiB
C
229 lines
6.8 KiB
C
/* media_params.c
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* Routines for parsing media type parameters as per RFC 822 and RFC 2045
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* Copyright 2004, Anders Broman.
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* Copyright 2004, Olivier Biot.
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*
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* Refer to the AUTHORS file or the AUTHORS section in the man page
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* for contacting the author(s) of this file.
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*
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* Wireshark - Network traffic analyzer
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* By Gerald Combs <gerald@wireshark.org>
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* Copyright 1998 Gerald Combs
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*
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* SPDX-License-Identifier: GPL-2.0-or-later
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*/
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#include "config.h"
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#include <string.h>
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#include <glib.h>
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#include <epan/media_params.h>
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static const char *
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ws_get_next_media_type_parameter(const char *pos, gsize *retnamelen,
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const char **retvalue, gsize *retvaluelen,
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const char **nextp)
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{
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const char *p, *namep, *valuep;
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char c;
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p = pos;
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while ((c = *p) != '\0' && g_ascii_isspace(c))
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p++; /* Skip white space */
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if (c == '\0') {
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/* No more parameters left */
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return NULL;
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}
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namep = p;
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/* Look for a '\0' (end of string), '=' (end of parameter name,
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beginning of parameter value), or ';' (end of parameter). */
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while ((c = *p) != '\0' && c != '=' && c != ';')
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p++;
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*retnamelen = (gsize) (p - namep);
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if (c == '\0') {
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/* End of string, so end of parameter, no parameter value */
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if (retvalue != NULL)
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*retvalue = NULL;
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if (retvaluelen != NULL)
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*retvaluelen = 0;
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*nextp = p;
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return namep;
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}
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if (c == ';') {
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/* End of parameter, no parameter value */
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if (retvalue != NULL)
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*retvalue = NULL;
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if (retvaluelen != NULL)
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*retvaluelen = 0;
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*nextp = p + 1;
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return namep;
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}
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/* The parameter has a value. Skip the '=' */
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p++;
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valuep = p;
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if (retvalue != NULL)
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*retvalue = valuep;
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/* Is the value a quoted string? */
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if (*p == '"') {
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/* Yes. Skip the opening quote, and scan forward looking for
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a non-escaped closing quote. */
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p++;
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for (;;) {
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c = *p;
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if (c == '\0') {
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/* End-of-string. We're done.
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(XXX - this is an error.) */
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if (retvaluelen != NULL) {
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*retvaluelen = (gsize) (p - valuep);
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}
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*nextp = p;
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return namep;
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}
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if (c == '"') {
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/* Closing quote. Skip it; we're done with
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the quoted-string. */
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p++;
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break;
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}
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if (c == '\\') {
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/* Backslash; this escapes the next character
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(quoted-pair). Skip the backslash, and make
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sure there *is* a next character. */
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p++;
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if (*p == '\0') {
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/* Nothing left; we're done.
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(XXX - this is an error.) */
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break;
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}
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}
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/* Skip the character we just processed. */
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p++;
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}
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/* Now scan forward looking for a '\0' (end of string)
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or ';' (end of parameter), in case there's any
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extra cruft after the quoted-string. */
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while ((c = *p) != '\0' && c != ';')
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p++;
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} else {
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/* No. Just scan forward looking for a '\0' (end
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of string) or ';' (end of parameter). */
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while ((c = *p) != '\0' && c != ';')
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p++;
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}
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if (c == '\0') {
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/* End of string, so end of parameter */
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if (retvaluelen != NULL) {
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*retvaluelen = (gsize) (p - valuep);
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}
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*nextp = p;
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return namep;
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}
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/* End of parameter; point past the terminating ';' */
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if (retvaluelen != NULL) {
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*retvaluelen = (gsize) (p - valuep);
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}
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*nextp = p + 1;
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return namep;
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}
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char *
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ws_find_media_type_parameter(wmem_allocator_t *scope, const char *parameters, const char *key)
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{
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const char *p, *name, *value;
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char c;
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gsize keylen, namelen, valuelen;
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char *valuestr, *vp;
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if (parameters == NULL || key == NULL)
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/* we won't be able to find anything */
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return NULL;
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keylen = (gsize) strlen(key);
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if (keylen == 0) {
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/* There's no parameter name to searh for */
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return NULL;
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}
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p = parameters;
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if (*p == '\0') {
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/* There are no parameters in which to search */
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return NULL;
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}
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do {
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/* Get the next parameter. */
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name = ws_get_next_media_type_parameter(p, &namelen, &value,
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&valuelen, &p);
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if (name == NULL) {
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/* No more parameters - not found. */
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return NULL;
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}
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/* Is it the parameter we're looking for? */
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if (namelen == keylen && g_ascii_strncasecmp(name, key, keylen) == 0) {
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/* Yes. */
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break;
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}
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} while (*p);
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if (value == NULL) {
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/* The parameter doesn't have a value. */
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return NULL;
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}
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/* We found the parameter with that name; now extract the value. */
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valuestr = (char *)wmem_alloc(scope, valuelen + 1);
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vp = valuestr;
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p = value;
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/* Is the value a quoted string? */
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if (*p == '"') {
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/* Yes. Skip the opening quote, and scan forward looking for
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a non-escaped closing quote, copying characters. */
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p++;
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for (;;) {
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c = *p;
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if (c == '\0') {
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/* End-of-string. We're done.
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(XXX - this is an error.) */
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*vp = '\0';
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return valuestr;
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}
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if (c == '"') {
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/* Closing quote. Skip it; we're done with
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the quoted-string. */
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p++;
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break;
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}
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if (c == '\\') {
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/* Backslash; this escapes the next character
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(quoted-pair). Skip the backslash, and make
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sure there *is* a next character. */
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p++;
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if (*p == '\0') {
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/* Nothing left; we're done.
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(XXX - this is an error.) */
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break;
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}
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}
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/* Copy the character. */
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*vp++ = *p++;
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}
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} else {
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/* No. Just scan forward until we see a '\0' (end of
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string or a non-token character, copying characters. */
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while ((c = *p) != '\0' && g_ascii_isgraph(c) && c != '(' &&
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c != ')' && c != '<' && c != '>' && c != '@' &&
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c != ',' && c != ';' && c != ':' && c != '\\' &&
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c != '"' && c != '/' && c != '[' && c != ']' &&
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c != '?' && c != '=' && c != '{' && c != '}') {
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*vp++ = c;
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p++;
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}
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}
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*vp = '\0';
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return valuestr;
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}
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