src/lib/gscpaux/json.cpp

   1 // Distributed under the MIT license. Copyright (c) 2010, Ivan Vashchaev\r
   2 \r
   3 #include <string.h>\r
   4 #include "json.h"\r
   5 \r
   6 // true if character represent a digit\r
   7 #define IS_DIGIT(c) (c >= '0' && c <= '9')\r
   8 \r
   9 // convert string to integer\r
  10 static char *atoi(char *first, char *last, int *out)\r
  11 {\r
  12         int sign = 1;\r
  13         if (first != last)\r
  14         {\r
  15                 if (*first == '-')\r
  16                 {\r
  17                         sign = -1;\r
  18                         ++first;\r
  19                 }\r
  20                 else if (*first == '+')\r
  21                 {\r
  22                         ++first;\r
  23                 }\r
  24         }\r
  25 \r
  26         int result = 0;\r
  27         for (; first != last && IS_DIGIT(*first); ++first)\r
  28         {\r
  29                 result = 10 * result + (*first - '0');\r
  30         }\r
  31         *out = result * sign;\r
  32 \r
  33         return first;\r
  34 }\r
  35 \r
  36 // convert hexadecimal string to unsigned integer\r
  37 static char *hatoui(char *first, char *last, unsigned int *out)\r
  38 {\r
  39         unsigned int result = 0;\r
  40         for (; first != last; ++first)\r
  41         {\r
  42                 int digit;\r
  43                 if (IS_DIGIT(*first))\r
  44                 {\r
  45                         digit = *first - '0';\r
  46                 }\r
  47                 else if (*first >= 'a' && *first <= 'f')\r
  48                 {\r
  49                         digit = *first - 'a' + 10;\r
  50                 }\r
  51                 else if (*first >= 'A' && *first <= 'F')\r
  52                 {\r
  53                         digit = *first - 'A' + 10;\r
  54                 }\r
  55                 else\r
  56                 {\r
  57                         break;\r
  58                 }\r
  59                 result = 16 * result + (unsigned int)digit;\r
  60         }\r
  61         *out = result;\r
  62 \r
  63         return first;\r
  64 }\r
  65 \r
  66 // convert string to floating point\r
  67 static char *atof(char *first, char *last, float *out)\r
  68 {\r
  69         // sign\r
  70         float sign = 1;\r
  71         if (first != last)\r
  72         {\r
  73                 if (*first == '-')\r
  74                 {\r
  75                         sign = -1;\r
  76                         ++first;\r
  77                 }\r
  78                 else if (*first == '+')\r
  79                 {\r
  80                         ++first;\r
  81                 }\r
  82         }\r
  83 \r
  84         // integer part\r
  85         float result = 0;\r
  86         for (; first != last && IS_DIGIT(*first); ++first)\r
  87         {\r
  88                 result = 10 * result + (float)(*first - '0');\r
  89         }\r
  90 \r
  91         // fraction part\r
  92         if (first != last && *first == '.')\r
  93         {\r
  94                 ++first;\r
  95 \r
  96                 float inv_base = 0.1f;\r
  97                 for (; first != last && IS_DIGIT(*first); ++first)\r
  98                 {\r
  99                         result += (float)(*first - '0') * inv_base;\r
 100                         inv_base *= 0.1f;\r
 101                 }\r
 102         }\r
 103 \r
 104         // result w\o exponent\r
 105         result *= sign;\r
 106 \r
 107         // exponent\r
 108         bool exponent_negative = false;\r
 109         int exponent = 0;\r
 110         if (first != last && (*first == 'e' || *first == 'E'))\r
 111         {\r
 112                 ++first;\r
 113 \r
 114                 if (*first == '-')\r
 115                 {\r
 116                         exponent_negative = true;\r
 117                         ++first;\r
 118                 }\r
 119                 else if (*first == '+')\r
 120                 {\r
 121                         ++first;\r
 122                 }\r
 123 \r
 124                 for (; first != last && IS_DIGIT(*first); ++first)\r
 125                 {\r
 126                         exponent = 10 * exponent + (*first - '0');\r
 127                 }\r
 128         }\r
 129 \r
 130         if (exponent)\r
 131         {\r
 132                 float power_of_ten = 10;\r
 133                 for (; exponent > 1; exponent--)\r
 134                 {\r
 135                         power_of_ten *= 10;\r
 136                 }\r
 137 \r
 138                 if (exponent_negative)\r
 139                 {\r
 140                         result /= power_of_ten;\r
 141                 }\r
 142                 else\r
 143                 {\r
 144                         result *= power_of_ten;\r
 145                 }\r
 146         }\r
 147 \r
 148         *out = result;\r
 149 \r
 150         return first;\r
 151 }\r
 152 \r
 153 static inline json_value *json_alloc(block_allocator *allocator)\r
 154 {\r
 155         json_value *value = (json_value *)allocator->malloc(sizeof(json_value));\r
 156         memset(value, 0, sizeof(json_value));\r
 157         return value;\r
 158 }\r
 159 \r
 160 static inline void json_append(json_value *lhs, json_value *rhs)\r
 161 {\r
 162         rhs->parent = lhs;\r
 163         if (lhs->last_child)\r
 164         {\r
 165                 lhs->last_child = lhs->last_child->next_sibling = rhs;\r
 166         }\r
 167         else\r
 168         {\r
 169                 lhs->first_child = lhs->last_child = rhs;\r
 170         }\r
 171 }\r
 172 \r
 173 #define ERROR(it, desc)\\r
 174         *error_pos = it;\\r
 175         *error_desc = desc;\\r
 176         *error_line = 1 - escaped_newlines;\\r
 177         for (char *c = it; c != source; --c)\\r
 178                 if (*c == '\n') ++*error_line;\\r
 179         return 0\r
 180 \r
 181 #define CHECK_TOP() if (!top) {ERROR(it, "Unexpected character");}\r
 182 \r
 183 json_value *json_parse(char *source, char **error_pos, const char **error_desc, int *error_line, block_allocator *allocator)\r
 184 {\r
 185         json_value *root = 0;\r
 186         json_value *top = 0;\r
 187 \r
 188         char *name = 0;\r
 189         char *it = source;\r
 190 \r
 191         int escaped_newlines = 0;\r
 192 \r
 193         while (*it)\r
 194         {\r
 195                 // skip white space\r
 196                 while (*it == '\x20' || *it == '\x9' || *it == '\xD' || *it == '\xA')\r
 197                 {\r
 198                         ++it;\r
 199                 }\r
 200 \r
 201                 switch (*it)\r
 202                 {\r
 203                 case '\0':\r
 204                         break;\r
 205                 case '{':\r
 206                 case '[':\r
 207                         {\r
 208                                 // create new value\r
 209                                 json_value *object = json_alloc(allocator);\r
 210 \r
 211                                 // name\r
 212                                 object->name = name;\r
 213                                 name = 0;\r
 214 \r
 215                                 // type\r
 216                                 object->type = (*it == '{') ? JSON_OBJECT : JSON_ARRAY;\r
 217 \r
 218                                 // skip open character\r
 219                                 ++it;\r
 220 \r
 221                                 // set top and root\r
 222                                 if (top)\r
 223                                 {\r
 224                                         json_append(top, object);\r
 225                                 }\r
 226                                 else if (!root)\r
 227                                 {\r
 228                                         root = object;\r
 229                                 }\r
 230                                 else\r
 231                                 {\r
 232                                         ERROR(it, "Second root. Only one root allowed");\r
 233                                 }\r
 234                                 top = object;\r
 235                         }\r
 236                         break;\r
 237 \r
 238                 case '}':\r
 239                 case ']':\r
 240                         {\r
 241                                 if (!top || top->type != ((*it == '}') ? JSON_OBJECT : JSON_ARRAY))\r
 242                                 {\r
 243                                         ERROR(it, "Mismatch closing brace/bracket");\r
 244                                 }\r
 245 \r
 246                                 // skip close character\r
 247                                 ++it;\r
 248 \r
 249                                 // set top\r
 250                                 top = top->parent;\r
 251                         }\r
 252                         break;\r
 253 \r
 254                 case ':':\r
 255                         if (!top || top->type != JSON_OBJECT)\r
 256                         {\r
 257                                 ERROR(it, "Unexpected character");\r
 258                         }\r
 259                         ++it;\r
 260                         break;\r
 261 \r
 262                 case ',':\r
 263                         CHECK_TOP();\r
 264                         ++it;\r
 265                         break;\r
 266 \r
 267                 case '"':\r
 268                         {\r
 269                                 CHECK_TOP();\r
 270 \r
 271                                 // skip '"' character\r
 272                                 ++it;\r
 273 \r
 274                                 char *first = it;\r
 275                                 char *last = it;\r
 276                                 while (*it)\r
 277                                 {\r
 278                                         if ((unsigned char)*it < '\x20')\r
 279                                         {\r
 280                                                 ERROR(first, "Control characters not allowed in strings");\r
 281                                         }\r
 282                                         else if (*it == '\\')\r
 283                                         {\r
 284                                                 switch (it[1])\r
 285                                                 {\r
 286                                                 case '"':\r
 287                                                         *last = '"';\r
 288                                                         break;\r
 289                                                 case '\\':\r
 290                                                         *last = '\\';\r
 291                                                         break;\r
 292                                                 case '/':\r
 293                                                         *last = '/';\r
 294                                                         break;\r
 295                                                 case 'b':\r
 296                                                         *last = '\b';\r
 297                                                         break;\r
 298                                                 case 'f':\r
 299                                                         *last = '\f';\r
 300                                                         break;\r
 301                                                 case 'n':\r
 302                                                         *last = '\n';\r
 303                                                         ++escaped_newlines;\r
 304                                                         break;\r
 305                                                 case 'r':\r
 306                                                         *last = '\r';\r
 307                                                         break;\r
 308                                                 case 't':\r
 309                                                         *last = '\t';\r
 310                                                         break;\r
 311                                                 case 'u':\r
 312                                                         {\r
 313                                                                 unsigned int codepoint;\r
 314                                                                 if (hatoui(it + 2, it + 6, &codepoint) != it + 6)\r
 315                                                                 {\r
 316                                                                         ERROR(it, "Bad unicode codepoint");\r
 317                                                                 }\r
 318 \r
 319                                                                 if (codepoint <= 0x7F)\r
 320                                                                 {\r
 321                                                                         *last = (char)codepoint;\r
 322                                                                 }\r
 323                                                                 else if (codepoint <= 0x7FF)\r
 324                                                                 {\r
 325                                                                         *last++ = (char)(0xC0 | (codepoint >> 6));\r
 326                                                                         *last = (char)(0x80 | (codepoint & 0x3F));\r
 327                                                                 }\r
 328                                                                 else if (codepoint <= 0xFFFF)\r
 329                                                                 {\r
 330                                                                         *last++ = (char)(0xE0 | (codepoint >> 12));\r
 331                                                                         *last++ = (char)(0x80 | ((codepoint >> 6) & 0x3F));\r
 332                                                                         *last = (char)(0x80 | (codepoint & 0x3F));\r
 333                                                                 }\r
 334                                                         }\r
 335                                                         it += 4;\r
 336                                                         break;\r
 337                                                 default:\r
 338                                                         ERROR(first, "Unrecognized escape sequence");\r
 339                                                 }\r
 340 \r
 341                                                 ++last;\r
 342                                                 it += 2;\r
 343                                         }\r
 344                                         else if (*it == '"')\r
 345                                         {\r
 346                                                 *last = 0;\r
 347                                                 ++it;\r
 348                                                 break;\r
 349                                         }\r
 350                                         else\r
 351                                         {\r
 352                                                 *last++ = *it++;\r
 353                                         }\r
 354                                 }\r
 355 \r
 356                                 if (!name && top->type == JSON_OBJECT)\r
 357                                 {\r
 358                                         // field name in object\r
 359                                         name = first;\r
 360                                 }\r
 361                                 else\r
 362                                 {\r
 363                                         // new string value\r
 364                                         json_value *object = json_alloc(allocator);\r
 365 \r
 366                                         object->name = name;\r
 367                                         name = 0;\r
 368 \r
 369                                         object->type = JSON_STRING;\r
 370                                         object->string_value = first;\r
 371 \r
 372                                         json_append(top, object);\r
 373                                 }\r
 374                         }\r
 375                         break;\r
 376 \r
 377                 case 'n':\r
 378                 case 't':\r
 379                 case 'f':\r
 380                         {\r
 381                                 CHECK_TOP();\r
 382 \r
 383                                 // new null/bool value\r
 384                                 json_value *object = json_alloc(allocator);\r
 385 \r
 386                                 object->name = name;\r
 387                                 name = 0;\r
 388 \r
 389                                 // null\r
 390                                 if (it[0] == 'n' && it[1] == 'u' && it[2] == 'l' && it[3] == 'l')\r
 391                                 {\r
 392                                         object->type = JSON_NULL;\r
 393                                         it += 4;\r
 394                                 }\r
 395                                 // true\r
 396                                 else if (it[0] == 't' && it[1] == 'r' && it[2] == 'u' && it[3] == 'e')\r
 397                                 {\r
 398                                         object->type = JSON_BOOL;\r
 399                                         object->int_value = 1;\r
 400                                         it += 4;\r
 401                                 }\r
 402                                 // false\r
 403                                 else if (it[0] == 'f' && it[1] == 'a' && it[2] == 'l' && it[3] == 's' && it[4] == 'e')\r
 404                                 {\r
 405                                         object->type = JSON_BOOL;\r
 406                                         object->int_value = 0;\r
 407                                         it += 5;\r
 408                                 }\r
 409                                 else\r
 410                                 {\r
 411                                         ERROR(it, "Unknown identifier");\r
 412                                 }\r
 413 \r
 414                                 json_append(top, object);\r
 415                         }\r
 416                         break;\r
 417 \r
 418                 case '-':\r
 419                 case '0':\r
 420                 case '1':\r
 421                 case '2':\r
 422                 case '3':\r
 423                 case '4':\r
 424                 case '5':\r
 425                 case '6':\r
 426                 case '7':\r
 427                 case '8':\r
 428                 case '9':\r
 429                         {\r
 430                                 CHECK_TOP();\r
 431 \r
 432                                 // new number value\r
 433                                 json_value *object = json_alloc(allocator);\r
 434 \r
 435                                 object->name = name;\r
 436                                 name = 0;\r
 437 \r
 438                                 object->type = JSON_INT;\r
 439 \r
 440                                 char *first = it;\r
 441                                 while (*it != '\x20' && *it != '\x9' && *it != '\xD' && *it != '\xA' && *it != ',' && *it != ']' && *it != '}')\r
 442                                 {\r
 443                                         if (*it == '.' || *it == 'e' || *it == 'E')\r
 444                                         {\r
 445                                                 object->type = JSON_FLOAT;\r
 446                                         }\r
 447                                         ++it;\r
 448                                 }\r
 449 \r
 450                                 if (object->type == JSON_INT && atoi(first, it, &object->int_value) != it)\r
 451                                 {\r
 452                                         ERROR(first, "Bad integer number");\r
 453                                 }\r
 454 \r
 455                                 if (object->type == JSON_FLOAT && atof(first, it, &object->float_value) != it)\r
 456                                 {\r
 457                                         ERROR(first, "Bad float number");\r
 458                                 }\r
 459 \r
 460                                 json_append(top, object);\r
 461                         }\r
 462                         break;\r
 463 \r
 464                 default:\r
 465                         ERROR(it, "Unexpected character");\r
 466                 }\r
 467         }\r
 468 \r
 469         if (top)\r
 470         {\r
 471                 ERROR(it, "Not all objects/arrays have been properly closed");\r
 472         }\r
 473 \r
 474         return root;\r
 475 }\r