C-based memory friendly JSON parser based on Serge Zaitsev's JSMN (https://bitbucket.org/zserge/jsmn/wiki/Home)
Dependents: _library_jsmn _library_jsmn _library_jsmn
JSMN
jsmn (pronounced like 'jasmine') is a minimalistic JSON parser in C. It can be easily integrated into resource-limited or embedded projects.
You can find more information about JSON format at json.org
Library sources are available at https://bitbucket.org/zserge/jsmn
The web page with some information about jsmn can be found at http://zserge.com/jsmn.html
jsmn.cpp
- Committer:
- yoonghm
- Date:
- 2014-11-17
- Revision:
- 2:5167da2fcc4e
- Parent:
- 1:70061827a9c8
File content as of revision 2:5167da2fcc4e:
/* C-based low-memory footprint JSON parser for mbed * Based on Serge Zaitsev's JSMN https://bitbucket.org/zserge/jsmn/wiki/Home * JSMN is distributed under MIT license. * * Copyright (c) 2010 Serge A. Zaitsev * Copyright (c) 2014 YoongHM * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN * THE SOFTWARE. */ #include <stdlib.h> #include "mbed.h" #include "jsmn.h" /** * Allocates a fresh unused token from the token pull. */ static jsmntok_t * jsmn_alloc_token (jsmn_parser *parser ,jsmntok_t *tokens ,size_t num_tokens ) { jsmntok_t *tok; if (parser->toknext >= num_tokens) { return NULL; } tok = &tokens[parser->toknext++]; tok->start = tok->end = -1; tok->size = 0; tok->parent = -1; return tok; } /** * Fills token type and boundaries. */ static void jsmn_fill_token (jsmntok_t *token ,jsmntype_t type ,int start ,int end ) { token->type = type; token->start = start; token->end = end; token->size = 0; } /** * Fills next available token with JSON primitive. */ static int jsmn_parse_primitive (jsmn_parser *parser ,const char *js ,size_t len ,jsmntok_t *tokens ,size_t num_tokens ) { jsmntok_t *token; int start; start = parser->pos; for (; parser->pos < len && js[parser->pos] != '\0'; parser->pos++) { switch (js[parser->pos]) { case '\t': case '\r': case '\n': case ' ' : case ',' : case ']' : case '}' : goto found; } if (js[parser->pos] < 32 || js[parser->pos] >= 127) { parser->pos = start; printf("%s:%d: parser->pos=%d\r\n", __FILE__, __LINE__, parser->pos); return JSMN_ERR_INVAL; } } parser->pos = start; return JSMN_ERR_PART; found: if (tokens == NULL) { parser->pos--; return 0; } token = jsmn_alloc_token(parser, tokens, num_tokens); if (token == NULL) { parser->pos = start; return JSMN_ERR_NOMEM; } jsmn_fill_token(token, JSMN_PRIMITIVE, start, parser->pos); token->parent = parser->toksuper; parser->pos--; return 0; } /** * Fill next token with JSON string. */ static int jsmn_parse_string (jsmn_parser *parser ,const char *js ,size_t len ,jsmntok_t *tokens ,size_t num_tokens ) { jsmntok_t *token; int start = parser->pos; parser->pos++; /* Skip starting quote */ for (; parser->pos < len && js[parser->pos] != '\0'; parser->pos++) { char c = js[parser->pos]; /* Quote: end of string */ if (c == '\"') { if (tokens == NULL) return 0; token = jsmn_alloc_token(parser, tokens, num_tokens); if (token == NULL) { parser->pos = start; return JSMN_ERR_NOMEM; } jsmn_fill_token(token, JSMN_STRING, start+1, parser->pos); token->parent = parser->toksuper; return 0; } /* Backslash: Quoted symbol expected */ if (c == '\\' && parser->pos + 1 < len) { int i; parser->pos++; switch (js[parser->pos]) { /* Allowed escaped symbols */ case '\"': case '/' : case '\\': case 'b' : case 'f' : case 'r' : case 'n' : case 't' : break; /* Allows escaped symbol \uXXXX */ case 'u': parser->pos++; for (i = 0; i < 4 && parser->pos < len && js[parser->pos] != '\0'; i++) { /* If it isn't a hex character we have an ERR */ if (!((js[parser->pos] >= 48 && js[parser->pos] <= 57) || /* 0-9 */ (js[parser->pos] >= 65 && js[parser->pos] <= 70) || /* A-F */ (js[parser->pos] >= 97 && js[parser->pos] <= 102))) { /* a-f */ parser->pos = start; printf("%s:%d: parser->pos=%d\r\n", __FILE__, __LINE__, parser->pos); return JSMN_ERR_INVAL; } parser->pos++; } parser->pos--; break; /* Unexpected symbol */ default: parser->pos = start; printf("%s:%d: parser->pos=%d\r\n", __FILE__, __LINE__, parser->pos); return JSMN_ERR_INVAL; } } } parser->pos = start; return JSMN_ERR_PART; } /** * Parse JSON string and fill tokens. */ int jsmn_parse (jsmn_parser *parser ,const char *js ,size_t len ,jsmntok_t *tokens ,unsigned int num_tokens ) { int r; int i; jsmntok_t *token; int count = 0; for (; parser->pos < len && js[parser->pos] != '\0'; parser->pos++) { char c; jsmntype_t type = JSMN_INVALID; c = js[parser->pos]; switch (c) { case '{' : case '[' : count++; if (tokens == NULL) break; token = jsmn_alloc_token(parser, tokens, num_tokens); if (token == NULL) return JSMN_ERR_NOMEM; if (parser->toksuper != -1) { tokens[parser->toksuper].size++; token->parent = parser->toksuper; } token->type = (c == '{' ? JSMN_OBJECT : JSMN_ARRAY); token->start = parser->pos; parser->toksuper = parser->toknext - 1; break; case '}': case ']': if (tokens == NULL) break; type = (c == '}' ? JSMN_OBJECT : JSMN_ARRAY); if (parser->toknext < 1) { printf("%s:%d: parser->pos=%d\r\n", __FILE__, __LINE__, parser->pos); return JSMN_ERR_INVAL; } token = &tokens[parser->toknext - 1]; for (;;) { if (token->start != -1 && token->end == -1) { if (token->type != type) { printf("%s:%d: parser->pos=%d\r\n", __FILE__, __LINE__, parser->pos); return JSMN_ERR_INVAL; } token->end = parser->pos + 1; parser->toksuper = token->parent; break; } if (token->parent == -1) break; token = &tokens[token->parent]; } break; case '\"': r = jsmn_parse_string(parser, js, len, tokens, num_tokens); if (r < 0) return r; count++; if (parser->toksuper != -1 && tokens != NULL) tokens[parser->toksuper].size++; break; case '\t': case '\r': case '\n': case ' ' : break; case ':' : parser->toksuper = parser->toknext - 1; break; case ',' : if (tokens != NULL && tokens[parser->toksuper].type != JSMN_ARRAY && tokens[parser->toksuper].type != JSMN_OBJECT) { parser->toksuper = tokens[parser->toksuper].parent; } break; case '-' : case '0' : case '1' : case '2' : case '3' : case '4' : case '5' : case '6' : case '7' : case '8' : case '9' : case 't' : case 'f' : case 'n' : /* And they must not be keys of the object */ if (tokens != NULL) { jsmntok_t *t = &tokens[parser->toksuper]; if ( t->type == JSMN_OBJECT || (t->type == JSMN_STRING && t->size != 0)) { printf("%s:%d: js[parser->pos]=%c\r\n", __FILE__, __LINE__, js[parser->pos]); return JSMN_ERR_INVAL; } } r = jsmn_parse_primitive(parser, js, len, tokens, num_tokens); if (r < 0) return r; count++; if (parser->toksuper != -1 && tokens != NULL) tokens[parser->toksuper].size++; break; /* Unexpected char in strict mode */ default: printf("%s:%d: js[parser->pos]=%c\r\n", __FILE__, __LINE__, js[parser->pos]); return JSMN_ERR_INVAL; } } for (i = parser->toknext - 1; i >= 0; i--) { /* Unmatched opened object or array */ if (tokens[i].start != -1 && tokens[i].end == -1) { return JSMN_ERR_PART; } } return count; } /** * Creates a new parser based over a given buffer with an array of tokens * available. */ void jsmn_init (jsmn_parser *parser) { parser->pos = 0; parser->toknext = 0; parser->toksuper = -1; }