![Dario Lombardo](/assets/img/avatar_default.png)
To check if a payload is json, the library libjsmn has been added to the source tree, with its licence (MIT). TODO: the libjsmn can be used to extract tokens in the standard dissection other than heurisitic part. HPFEEDS dissector has also been changed in order to leverage the new json dissector. Bug: 10834 Change-Id: Ib1df2a699982dbdd2b5418e97edbdb5cbd9c8978 Reviewed-on: https://code.wireshark.org/review/6350 Petri-Dish: Alexis La Goutte <alexis.lagoutte@gmail.com> Reviewed-by: Alexis La Goutte <alexis.lagoutte@gmail.com> Reviewed-by: Michael Mann <mmann78@netscape.net>
346 lines
8.8 KiB
C
346 lines
8.8 KiB
C
/*
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* Copyright (c) 2010 Serge A. Zaitsev
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include <stdlib.h>
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#include "jsmn.h"
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/**
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* Allocates a fresh unused token from the token pull.
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*/
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static jsmntok_t *jsmn_alloc_token(jsmn_parser *parser,
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jsmntok_t *tokens, size_t num_tokens) {
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jsmntok_t *tok;
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if (parser->toknext >= num_tokens) {
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return NULL;
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}
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tok = &tokens[parser->toknext++];
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tok->start = tok->end = -1;
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tok->size = 0;
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#ifdef JSMN_PARENT_LINKS
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tok->parent = -1;
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#endif
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return tok;
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}
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/**
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* Fills token type and boundaries.
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*/
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static void jsmn_fill_token(jsmntok_t *token, jsmntype_t type,
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int start, int end) {
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token->type = type;
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token->start = start;
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token->end = end;
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token->size = 0;
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}
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/**
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* Fills next available token with JSON primitive.
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*/
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static int jsmn_parse_primitive(jsmn_parser *parser, const char *js,
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size_t len, jsmntok_t *tokens, size_t num_tokens) {
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jsmntok_t *token;
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int start;
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start = parser->pos;
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for (; parser->pos < len && js[parser->pos] != '\0'; parser->pos++) {
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switch (js[parser->pos]) {
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#ifndef JSMN_STRICT
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/* In strict mode primitive must be followed by "," or "}" or "]" */
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case ':':
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#endif
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case '\t' : case '\r' : case '\n' : case ' ' :
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case ',' : case ']' : case '}' :
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goto found;
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}
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if (js[parser->pos] < 32 || js[parser->pos] >= 127) {
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parser->pos = start;
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return JSMN_ERROR_INVAL;
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}
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}
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#ifdef JSMN_STRICT
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/* In strict mode primitive must be followed by a comma/object/array */
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parser->pos = start;
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return JSMN_ERROR_PART;
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#endif
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found:
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if (tokens == NULL) {
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parser->pos--;
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return 0;
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}
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token = jsmn_alloc_token(parser, tokens, num_tokens);
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if (token == NULL) {
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parser->pos = start;
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return JSMN_ERROR_NOMEM;
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}
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jsmn_fill_token(token, JSMN_PRIMITIVE, start, parser->pos);
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#ifdef JSMN_PARENT_LINKS
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token->parent = parser->toksuper;
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#endif
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parser->pos--;
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return 0;
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}
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/**
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* Filsl next token with JSON string.
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*/
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static int jsmn_parse_string(jsmn_parser *parser, const char *js,
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size_t len, jsmntok_t *tokens, size_t num_tokens) {
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jsmntok_t *token;
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int start = parser->pos;
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parser->pos++;
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/* Skip starting quote */
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for (; parser->pos < len && js[parser->pos] != '\0'; parser->pos++) {
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char c = js[parser->pos];
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/* Quote: end of string */
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if (c == '\"') {
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if (tokens == NULL) {
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return 0;
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}
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token = jsmn_alloc_token(parser, tokens, num_tokens);
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if (token == NULL) {
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parser->pos = start;
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return JSMN_ERROR_NOMEM;
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}
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jsmn_fill_token(token, JSMN_STRING, start+1, parser->pos);
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#ifdef JSMN_PARENT_LINKS
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token->parent = parser->toksuper;
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#endif
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return 0;
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}
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/* Backslash: Quoted symbol expected */
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if (c == '\\' && parser->pos + 1 < len) {
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int i;
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parser->pos++;
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switch (js[parser->pos]) {
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/* Allowed escaped symbols */
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case '\"': case '/' : case '\\' : case 'b' :
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case 'f' : case 'r' : case 'n' : case 't' :
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break;
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/* Allows escaped symbol \uXXXX */
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case 'u':
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parser->pos++;
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for(i = 0; i < 4 && parser->pos < len && js[parser->pos] != '\0'; i++) {
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/* If it isn't a hex character we have an error */
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if(!((js[parser->pos] >= 48 && js[parser->pos] <= 57) || /* 0-9 */
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(js[parser->pos] >= 65 && js[parser->pos] <= 70) || /* A-F */
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(js[parser->pos] >= 97 && js[parser->pos] <= 102))) { /* a-f */
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parser->pos = start;
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return JSMN_ERROR_INVAL;
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}
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parser->pos++;
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}
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parser->pos--;
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break;
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/* Unexpected symbol */
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default:
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parser->pos = start;
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return JSMN_ERROR_INVAL;
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}
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}
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}
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parser->pos = start;
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return JSMN_ERROR_PART;
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}
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/**
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* Parse JSON string and fill tokens.
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*/
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int jsmn_parse(jsmn_parser *parser, const char *js, size_t len,
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jsmntok_t *tokens, unsigned int num_tokens) {
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int r;
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int i;
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jsmntok_t *token;
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int count = 0;
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for (; parser->pos < len && js[parser->pos] != '\0'; parser->pos++) {
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char c;
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jsmntype_t type;
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c = js[parser->pos];
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switch (c) {
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case '{': case '[':
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count++;
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if (tokens == NULL) {
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break;
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}
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token = jsmn_alloc_token(parser, tokens, num_tokens);
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if (token == NULL)
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return JSMN_ERROR_NOMEM;
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if (parser->toksuper != -1) {
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tokens[parser->toksuper].size++;
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#ifdef JSMN_PARENT_LINKS
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token->parent = parser->toksuper;
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#endif
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}
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token->type = (c == '{' ? JSMN_OBJECT : JSMN_ARRAY);
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token->start = parser->pos;
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parser->toksuper = parser->toknext - 1;
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break;
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case '}': case ']':
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if (tokens == NULL)
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break;
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type = (c == '}' ? JSMN_OBJECT : JSMN_ARRAY);
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#ifdef JSMN_PARENT_LINKS
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if (parser->toknext < 1) {
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return JSMN_ERROR_INVAL;
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}
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token = &tokens[parser->toknext - 1];
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for (;;) {
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if (token->start != -1 && token->end == -1) {
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if (token->type != type) {
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return JSMN_ERROR_INVAL;
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}
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token->end = parser->pos + 1;
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parser->toksuper = token->parent;
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break;
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}
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if (token->parent == -1) {
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break;
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}
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token = &tokens[token->parent];
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}
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#else
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for (i = parser->toknext - 1; i >= 0; i--) {
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token = &tokens[i];
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if (token->start != -1 && token->end == -1) {
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if (token->type != type) {
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return JSMN_ERROR_INVAL;
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}
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parser->toksuper = -1;
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token->end = parser->pos + 1;
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break;
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}
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}
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/* Error if unmatched closing bracket */
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if (i == -1) return JSMN_ERROR_INVAL;
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for (; i >= 0; i--) {
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token = &tokens[i];
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if (token->start != -1 && token->end == -1) {
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parser->toksuper = i;
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break;
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}
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}
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#endif
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break;
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case '\"':
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r = jsmn_parse_string(parser, js, len, tokens, num_tokens);
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if (r < 0) return r;
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count++;
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if (parser->toksuper != -1 && tokens != NULL)
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tokens[parser->toksuper].size++;
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break;
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case '\t' : case '\r' : case '\n' : case ' ':
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break;
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case ':':
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parser->toksuper = parser->toknext - 1;
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break;
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case ',':
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if (tokens != NULL &&
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tokens[parser->toksuper].type != JSMN_ARRAY &&
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tokens[parser->toksuper].type != JSMN_OBJECT) {
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#ifdef JSMN_PARENT_LINKS
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parser->toksuper = tokens[parser->toksuper].parent;
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#else
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for (i = parser->toknext - 1; i >= 0; i--) {
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if (tokens[i].type == JSMN_ARRAY || tokens[i].type == JSMN_OBJECT) {
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if (tokens[i].start != -1 && tokens[i].end == -1) {
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parser->toksuper = i;
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break;
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}
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}
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}
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#endif
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}
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break;
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#ifdef JSMN_STRICT
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/* In strict mode primitives are: numbers and booleans */
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case '-': case '0': case '1' : case '2': case '3' : case '4':
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case '5': case '6': case '7' : case '8': case '9':
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case 't': case 'f': case 'n' :
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/* And they must not be keys of the object */
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if (tokens != NULL) {
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jsmntok_t *t = &tokens[parser->toksuper];
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if (t->type == JSMN_OBJECT ||
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(t->type == JSMN_STRING && t->size != 0)) {
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return JSMN_ERROR_INVAL;
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}
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}
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#else
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/* In non-strict mode every unquoted value is a primitive */
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default:
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#endif
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r = jsmn_parse_primitive(parser, js, len, tokens, num_tokens);
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if (r < 0) return r;
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count++;
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if (parser->toksuper != -1 && tokens != NULL)
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tokens[parser->toksuper].size++;
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break;
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#ifdef JSMN_STRICT
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/* Unexpected char in strict mode */
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default:
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return JSMN_ERROR_INVAL;
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#endif
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}
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}
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for (i = parser->toknext - 1; i >= 0; i--) {
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/* Unmatched opened object or array */
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if (tokens[i].start != -1 && tokens[i].end == -1) {
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return JSMN_ERROR_PART;
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}
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}
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return count;
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}
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/**
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* Creates a new parser based over a given buffer with an array of tokens
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* available.
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*/
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void jsmn_init(jsmn_parser *parser) {
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parser->pos = 0;
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parser->toknext = 0;
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parser->toksuper = -1;
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}
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/*
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* Editor modelines - http://www.wireshark.org/tools/modelines.html
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*
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* Local variables:
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* c-basic-offset: 4
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* tab-width: 4
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* indent-tabs-mode: nil
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* End:
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*
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* vi: set shiftwidth=4 tabstop=4 expandtab:
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* :indentSize=4:tabSize=4:noTabs=true:
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*/
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