contrib/ntp/libjsmn/jsmn.c

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