src/jsmn.c

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