jsmn/jsmn.c

   1 #include "jsmn.h"
   2
   3 /**
   4  * Allocates a fresh unused token from the token pool.
   5  */
   6 static jsmntok_t *jsmn_alloc_token(jsmn_parser *parser,
   7                 jsmntok_t *tokens, size_t num_tokens) {
   8         jsmntok_t *tok;
   9         if (parser->toknext >= num_tokens) {
  10                 return NULL;
  11         }
  12         tok = &tokens[parser->toknext++];
  13         tok->start = tok->end = -1;
  14         tok->size = 0;
  15 #ifdef JSMN_PARENT_LINKS
  16         tok->parent = -1;
  17 #endif
  18         return tok;
  19 }
  20
  21 /**
  22  * Fills token type and boundaries.
  23  */
  24 static void jsmn_fill_token(jsmntok_t *token, jsmntype_t type,
  25                             int start, int end) {
  26         token->type = type;
  27         token->start = start;
  28         token->end = end;
  29         token->size = 0;
  30 }
  31
  32 /**
  33  * Fills next available token with JSON primitive.
  34  */
  35 static int jsmn_parse_primitive(jsmn_parser *parser, const char *js,
  36                 size_t len, jsmntok_t *tokens, size_t num_tokens) {
  37         jsmntok_t *token;
  38         int start;
  39
  40         start = parser->pos;
  41
  42         for (; parser->pos < len && js[parser->pos] != '\0'; parser->pos++) {
  43                 switch (js[parser->pos]) {
  44 #ifndef JSMN_STRICT
  45                         /* In strict mode primitive must be followed by "," or "}" or "]" */
  46                         case ':':
  47 #endif
  48                         case '\t' : case '\r' : case '\n' : case ' ' :
  49                         case ','  : case ']'  : case '}' :
  50                                 goto found;
  51                 }
  52                 if (js[parser->pos] < 32 || js[parser->pos] >= 127) {
  53                         parser->pos = start;
  54                         return JSMN_ERROR_INVAL;
  55                 }
  56         }
  57 #ifdef JSMN_STRICT
  58         /* In strict mode primitive must be followed by a comma/object/array */
  59         parser->pos = start;
  60         return JSMN_ERROR_PART;
  61 #endif
  62
  63 found:
  64         if (tokens == NULL) {
  65                 parser->pos--;
  66                 return 0;
  67         }
  68         token = jsmn_alloc_token(parser, tokens, num_tokens);
  69         if (token == NULL) {
  70                 parser->pos = start;
  71                 return JSMN_ERROR_NOMEM;
  72         }
  73         jsmn_fill_token(token, JSMN_PRIMITIVE, start, parser->pos);
  74 #ifdef JSMN_PARENT_LINKS
  75         token->parent = parser->toksuper;
  76 #endif
  77         parser->pos--;
  78         return 0;
  79 }
  80
  81 /**
  82  * Fills next token with JSON string.
  83  */
  84 static int jsmn_parse_string(jsmn_parser *parser, const char *js,
  85                 size_t len, jsmntok_t *tokens, size_t num_tokens) {
  86         jsmntok_t *token;
  87
  88         int start = parser->pos;
  89
  90         parser->pos++;
  91
  92         /* Skip starting quote */
  93         for (; parser->pos < len && js[parser->pos] != '\0'; parser->pos++) {
  94                 char c = js[parser->pos];
  95
  96                 /* Quote: end of string */
  97                 if (c == '\"') {
  98                         if (tokens == NULL) {
  99                                 return 0;
 100                         }
 101                         token = jsmn_alloc_token(parser, tokens, num_tokens);
 102                         if (token == NULL) {
 103                                 parser->pos = start;
 104                                 return JSMN_ERROR_NOMEM;
 105                         }
 106                         jsmn_fill_token(token, JSMN_STRING, start+1, parser->pos);
 107 #ifdef JSMN_PARENT_LINKS
 108                         token->parent = parser->toksuper;
 109 #endif
 110                         return 0;
 111                 }
 112
 113                 /* Backslash: Quoted symbol expected */
 114                 if (c == '\\' && parser->pos + 1 < len) {
 115                         int i;
 116                         parser->pos++;
 117                         switch (js[parser->pos]) {
 118                                 /* Allowed escaped symbols */
 119                                 case '\"': case '/' : case '\\' : case 'b' :
 120                                 case 'f' : case 'r' : case 'n'  : case 't' :
 121                                         break;
 122                                 /* Allows escaped symbol \uXXXX */
 123                                 case 'u':
 124                                         parser->pos++;
 125                                         for(i = 0; i < 4 && parser->pos < len && js[parser->pos] != '\0'; i++) {
 126                                                 /* If it isn't a hex character we have an error */
 127                                                 if(!((js[parser->pos] >= 48 && js[parser->pos] <= 57) || /* 0-9 */
 128                                                                         (js[parser->pos] >= 65 && js[parser->pos] <= 70) || /* A-F */
 129                                                                         (js[parser->pos] >= 97 && js[parser->pos] <= 102))) { /* a-f */
 130                                                         parser->pos = start;
 131                                                         return JSMN_ERROR_INVAL;
 132                                                 }
 133                                                 parser->pos++;
 134                                         }
 135                                         parser->pos--;
 136                                         break;
 137                                 /* Unexpected symbol */
 138                                 default:
 139                                         parser->pos = start;
 140                                         return JSMN_ERROR_INVAL;
 141                         }
 142                 }
 143         }
 144         parser->pos = start;
 145         return JSMN_ERROR_PART;
 146 }
 147
 148 /**
 149  * Parse JSON string and fill tokens.
 150  */
 151 int jsmn_parse(jsmn_parser *parser, const char *js, size_t len,
 152                 jsmntok_t *tokens, unsigned int num_tokens) {
 153         int r;
 154         int i;
 155         jsmntok_t *token;
 156         int count = parser->toknext;
 157
 158         for (; parser->pos < len && js[parser->pos] != '\0'; parser->pos++) {
 159                 char c;
 160                 jsmntype_t type;
 161
 162                 c = js[parser->pos];
 163                 switch (c) {
 164                         case '{': case '[':
 165                                 count++;
 166                                 if (tokens == NULL) {
 167                                         break;
 168                                 }
 169                                 token = jsmn_alloc_token(parser, tokens, num_tokens);
 170                                 if (token == NULL)
 171                                         return JSMN_ERROR_NOMEM;
 172                                 if (parser->toksuper != -1) {
 173                                         if (tokens[parser->toksuper].type == JSMN_OBJECT) {
 174                                                 /* Object keys must be strings, not objects or arrays */
 175                                                 return JSMN_ERROR_INVAL;
 176                                         }
 177                                         tokens[parser->toksuper].size++;
 178 #ifdef JSMN_PARENT_LINKS
 179                                         token->parent = parser->toksuper;
 180 #endif
 181                                 }
 182                                 token->type = (c == '{' ? JSMN_OBJECT : JSMN_ARRAY);
 183                                 token->start = parser->pos;
 184                                 parser->toksuper = parser->toknext - 1;
 185                                 break;
 186                         case '}': case ']':
 187                                 if (tokens == NULL)
 188                                         break;
 189                                 type = (c == '}' ? JSMN_OBJECT : JSMN_ARRAY);
 190 #ifdef JSMN_PARENT_LINKS
 191                                 if (parser->toknext < 1) {
 192                                         return JSMN_ERROR_INVAL;
 193                                 }
 194                                 token = &tokens[parser->toknext - 1];
 195                                 for (;;) {
 196                                         if (token->start != -1 && token->end == -1) {
 197                                                 if (token->type != type) {
 198                                                         return JSMN_ERROR_INVAL;
 199                                                 }
 200                                                 token->end = parser->pos + 1;
 201                                                 parser->toksuper = token->parent;
 202                                                 break;
 203                                         }
 204                                         if (token->parent == -1) {
 205                                                 if(token->type != type || parser->toksuper == -1) {
 206                                                         return JSMN_ERROR_INVAL;
 207                                                 }
 208                                                 break;
 209                                         }
 210                                         token = &tokens[token->parent];
 211                                 }
 212 #else
 213                                 for (i = parser->toknext - 1; i >= 0; i--) {
 214                                         token = &tokens[i];
 215                                         if (token->start != -1 && token->end == -1) {
 216                                                 if (token->type != type) {
 217                                                         return JSMN_ERROR_INVAL;
 218                                                 }
 219                                                 parser->toksuper = -1;
 220                                                 token->end = parser->pos + 1;
 221                                                 break;
 222                                         }
 223                                 }
 224                                 /* Error if unmatched closing bracket */
 225                                 if (i == -1) return JSMN_ERROR_INVAL;
 226                                 for (; i >= 0; i--) {
 227                                         token = &tokens[i];
 228                                         if (token->start != -1 && token->end == -1) {
 229                                                 parser->toksuper = i;
 230                                                 break;
 231                                         }
 232                                 }
 233 #endif
 234                                 break;
 235                         case '\"':
 236                                 r = jsmn_parse_string(parser, js, len, tokens, num_tokens);
 237                                 if (r < 0) return r;
 238                                 count++;
 239                                 if (parser->toksuper != -1 && tokens != NULL)
 240                                         tokens[parser->toksuper].size++;
 241                                 break;
 242                         case '\t' : case '\r' : case '\n' : case ' ':
 243                                 break;
 244                         case ':':
 245                                 parser->toksuper = parser->toknext - 1;
 246                                 break;
 247                         case ',':
 248                                 if (tokens != NULL && parser->toksuper != -1 &&
 249                                                 tokens[parser->toksuper].type != JSMN_ARRAY &&
 250                                                 tokens[parser->toksuper].type != JSMN_OBJECT) {
 251 #ifdef JSMN_PARENT_LINKS
 252                                         parser->toksuper = tokens[parser->toksuper].parent;
 253 #else
 254                                         for (i = parser->toknext - 1; i >= 0; i--) {
 255                                                 if (tokens[i].type == JSMN_ARRAY || tokens[i].type == JSMN_OBJECT) {
 256                                                         if (tokens[i].start != -1 && tokens[i].end == -1) {
 257                                                                 parser->toksuper = i;
 258                                                                 break;
 259                                                         }
 260                                                 }
 261                                         }
 262 #endif
 263                                 }
 264                                 break;
 265 #ifdef JSMN_STRICT
 266                         /* In strict mode primitives are: numbers and booleans */
 267                         case '-': case '0': case '1' : case '2': case '3' : case '4':
 268                         case '5': case '6': case '7' : case '8': case '9':
 269                         case 't': case 'f': case 'n' :
 270                                 /* And they must not be keys of the object */
 271                                 if (tokens != NULL && parser->toksuper != -1) {
 272                                         jsmntok_t *t = &tokens[parser->toksuper];
 273                                         if (t->type == JSMN_OBJECT ||
 274                                                         (t->type == JSMN_STRING && t->size != 0)) {
 275                                                 return JSMN_ERROR_INVAL;
 276                                         }
 277                                 }
 278 #else
 279                         /* In non-strict mode every unquoted value is a primitive */
 280                         default:
 281 #endif
 282                                 r = jsmn_parse_primitive(parser, js, len, tokens, num_tokens);
 283                                 if (r < 0) return r;
 284                                 count++;
 285                                 if (parser->toksuper != -1 && tokens != NULL)
 286                                         tokens[parser->toksuper].size++;
 287                                 break;
 288
 289 #ifdef JSMN_STRICT
 290                         /* Unexpected char in strict mode */
 291                         default:
 292                                 return JSMN_ERROR_INVAL;
 293 #endif
 294                 }
 295         }
 296
 297         if (tokens != NULL) {
 298                 for (i = parser->toknext - 1; i >= 0; i--) {
 299                         /* Unmatched opened object or array */
 300                         if (tokens[i].start != -1 && tokens[i].end == -1) {
 301                                 return JSMN_ERROR_PART;
 302                         }
 303                 }
 304         }
 305
 306         return count;
 307 }
 308
 309 /**
 310  * Creates a new parser based over a given  buffer with an array of tokens
 311  * available.
 312  */
 313 void jsmn_init(jsmn_parser *parser) {
 314         parser->pos = 0;
 315         parser->toknext = 0;
 316         parser->toksuper = -1;
 317 }
 318