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annotate libraries/json/json.c @ 143:6f723e60acdc

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Bugfixes in JSON library
author jbe
date Wed Jul 30 02:36:37 2014 +0200 (2014-07-30)
parents a686ed2ce967
children 0690fe79b673
rev   line source
jbe@121 1 #include <lua.h>
jbe@121 2 #include <lauxlib.h>
jbe@122 3 #include <stdlib.h>
jbe@121 4 #include <string.h>
jbe@121 5
jbe@142 6 #define JSON_MAXDEPTH 100
jbe@142 7
jbe@138 8 #define JSON_REGENT static char
jbe@138 9 #define JSON_REGREF void *
jbe@138 10
jbe@138 11 JSON_REGENT json_nullmark;
jbe@138 12 JSON_REGENT json_shadowtbl;
jbe@138 13 JSON_REGENT json_unknownmt;
jbe@138 14 JSON_REGENT json_objectmt;
jbe@138 15 JSON_REGENT json_arraymt;
jbe@138 16
jbe@138 17 #define json_regfetch(L, x) (lua_pushlightuserdata((L), &(x)), lua_rawget((L), LUA_REGISTRYINDEX))
jbe@138 18
jbe@138 19 #define json_regstore(L, x) (lua_pushlightuserdata(L, &(x)), lua_pushvalue(L, -2), lua_rawset(L, LUA_REGISTRYINDEX));
jbe@138 20
jbe@136 21 // marks a table as JSON object or JSON array:
jbe@136 22 // (returns its modified argument or a new table if argument is nil)
jbe@138 23 static int json_mark(lua_State *L, JSON_REGREF mt) {
jbe@136 24 // if argument is nil, then create new table:
jbe@136 25 if (lua_isnoneornil(L, 1)) {
jbe@136 26 lua_settop(L, 0);
jbe@136 27 lua_newtable(L);
jbe@136 28 // set shadow table:
jbe@143 29 json_regfetch(L, json_shadowtbl);
jbe@136 30 lua_pushvalue(L, 1);
jbe@136 31 lua_newtable(L);
jbe@143 32 lua_rawset(L, -3);
jbe@143 33 } else {
jbe@143 34 // check if shadow table already exists:
jbe@143 35 json_regfetch(L, json_shadowtbl);
jbe@143 36 lua_pushvalue(L, 1);
jbe@143 37 lua_rawget(L, -2);
jbe@143 38 if (lua_isnil(L, -1)) {
jbe@143 39 // set shadow table and leave it on top of stack:
jbe@143 40 lua_newtable(L);
jbe@143 41 lua_pushvalue(L, 1);
jbe@143 42 lua_pushvalue(L, -2);
jbe@143 43 lua_rawset(L, -5);
jbe@143 44 }
jbe@143 45 for(lua_pushnil(L); lua_next(L, 1); lua_pop(L, 1)) {
jbe@143 46 lua_pushvalue(L, -2);
jbe@143 47 lua_pushnil(L);
jbe@143 48 lua_rawset(L, 1);
jbe@143 49 lua_pushvalue(L, -2);
jbe@143 50 lua_pushvalue(L, -2);
jbe@143 51 lua_rawset(L, -5);
jbe@143 52 }
jbe@136 53 }
jbe@138 54 // discard everything but table to return:
jbe@138 55 lua_settop(L, 1);
jbe@136 56 // set metatable:
jbe@143 57 json_regfetch(L, *mt);
jbe@136 58 lua_setmetatable(L, 1);
jbe@138 59 // return table:
jbe@136 60 return 1;
jbe@136 61 }
jbe@136 62
jbe@136 63 // marks a table as JSON object:
jbe@136 64 // (returns its modified argument or a new table if argument is nil)
jbe@136 65 static int json_object(lua_State *L) {
jbe@138 66 return json_mark(L, &json_objectmt);
jbe@136 67 }
jbe@136 68
jbe@136 69 // marks a table as JSON array:
jbe@136 70 // (returns its modified argument or a new table if argument is nil)
jbe@136 71 static int json_array(lua_State *L) {
jbe@138 72 return json_mark(L, &json_arraymt);
jbe@136 73 }
jbe@136 74
jbe@124 75 #define JSON_STATE_VALUE 0
jbe@124 76 #define JSON_STATE_OBJECT_KEY 1
jbe@124 77 #define JSON_STATE_OBJECT_KEY_TERMINATOR 2
jbe@124 78 #define JSON_STATE_OBJECT_VALUE 3
jbe@124 79 #define JSON_STATE_OBJECT_SEPARATOR 4
jbe@124 80 #define JSON_STATE_ARRAY_VALUE 5
jbe@124 81 #define JSON_STATE_ARRAY_SEPARATOR 6
jbe@124 82 #define JSON_STATE_END 7
jbe@121 83
jbe@138 84 #define json_import_objectmt_idx 2
jbe@138 85 #define json_import_arraymt_idx 3
jbe@138 86 #define json_import_shadowtbl_idx 4
jbe@138 87 #define json_import_nullmark_idx 5
jbe@138 88
jbe@136 89 // decodes a JSON document:
jbe@121 90 static int json_import(lua_State *L) {
jbe@136 91 const char *str; // string to parse
jbe@136 92 size_t total; // total length of string to parse
jbe@136 93 size_t pos = 0; // current position in string to parse
jbe@136 94 size_t level = 0; // nested levels of objects/arrays currently being processed
jbe@136 95 int mode = JSON_STATE_VALUE; // state of parser
jbe@136 96 char c; // variable to store a single character to be processed
jbe@136 97 luaL_Buffer luabuf; // Lua buffer to decode (possibly escaped) strings
jbe@136 98 char *cbuf; // C buffer to decode (possibly escaped) strings
jbe@136 99 size_t writepos; // write position of decoded strings in C buffer
jbe@138 100 // limit stack to 1 element:
jbe@138 101 lua_settop(L, 1);
jbe@138 102 // push json_objectmt on stack position 2:
jbe@138 103 json_regfetch(L, json_objectmt);
jbe@138 104 // push json_arraymt on stack position 3:
jbe@138 105 json_regfetch(L, json_arraymt);
jbe@138 106 // push json_shadowtbl on stack position 4:
jbe@138 107 json_regfetch(L, json_shadowtbl);
jbe@138 108 // push json_nullmark on stack position 5:
jbe@138 109 json_regfetch(L, json_nullmark);
jbe@136 110 // require string as first argument:
jbe@136 111 str = luaL_checklstring(L, 1, &total);
jbe@136 112 // if string contains a NULL byte, this is a syntax error
jbe@136 113 if (strlen(str) != total) goto json_import_syntax_error;
jbe@136 114 // main loop of parser:
jbe@136 115 json_import_loop:
jbe@136 116 // skip whitespace and store next character in variable 'c':
jbe@121 117 while (c = str[pos], c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == '\f') pos++;
jbe@136 118 // switch statement to handle certain (single) characters:
jbe@121 119 switch (c) {
jbe@136 120 // handle end of JSON document:
jbe@121 121 case 0:
jbe@136 122 // if end of JSON document was expected, then return top element of stack as result:
jbe@124 123 if (mode == JSON_STATE_END) return 1;
jbe@136 124 // otherwise, the JSON document was malformed:
jbe@121 125 json_import_unexpected_eof:
jbe@121 126 lua_pushnil(L);
jbe@121 127 if (level == 0) lua_pushliteral(L, "Empty string");
jbe@121 128 else lua_pushliteral(L, "Unexpected end of JSON document");
jbe@121 129 return 2;
jbe@136 130 // new JSON object:
jbe@121 131 case '{':
jbe@136 132 // if a JSON object is not expected here, then return an error:
jbe@124 133 if (mode != JSON_STATE_VALUE && mode != JSON_STATE_OBJECT_VALUE && mode != JSON_STATE_ARRAY_VALUE)
jbe@121 134 goto json_import_syntax_error;
jbe@136 135 // create JSON object on stack:
jbe@136 136 lua_newtable(L);
jbe@136 137 // set metatable of JSON object:
jbe@138 138 lua_pushvalue(L, json_import_objectmt_idx);
jbe@125 139 lua_setmetatable(L, -2);
jbe@136 140 // create internal shadow table on stack:
jbe@136 141 lua_newtable(L);
jbe@138 142 // register internal shadow table (and cleanup stack afterwards):
jbe@123 143 lua_pushvalue(L, -2);
jbe@123 144 lua_pushvalue(L, -2);
jbe@138 145 lua_rawset(L, json_import_shadowtbl_idx);
jbe@136 146 // expect object key (or end of object) and continue with loop:
jbe@136 147 mode = JSON_STATE_OBJECT_KEY;
jbe@142 148 goto json_import_open;
jbe@136 149 // new JSON array:
jbe@121 150 case '[':
jbe@136 151 // if a JSON array is not expected here, then return an error:
jbe@124 152 if (mode != JSON_STATE_VALUE && mode != JSON_STATE_OBJECT_VALUE && mode != JSON_STATE_ARRAY_VALUE)
jbe@121 153 goto json_import_syntax_error;
jbe@136 154 // create JSON array on stack:
jbe@136 155 lua_newtable(L);
jbe@136 156 // set metatable of JSON array:
jbe@138 157 lua_pushvalue(L, json_import_arraymt_idx);
jbe@125 158 lua_setmetatable(L, -2);
jbe@136 159 // create internal shadow table on stack:
jbe@136 160 lua_newtable(L);
jbe@138 161 // register internal shadow table (and cleanup stack afterwards):
jbe@123 162 lua_pushvalue(L, -2);
jbe@123 163 lua_pushvalue(L, -2);
jbe@138 164 lua_rawset(L, json_import_shadowtbl_idx);
jbe@140 165 // add nil as key (needed to keep stack balance) and as magic to detect arrays:
jbe@140 166 lua_pushnil(L);
jbe@142 167 // expect array value (or end of array) and continue with loop:
jbe@142 168 mode = JSON_STATE_ARRAY_VALUE;
jbe@142 169 // continue with common code for opening JSON object and JSON array:
jbe@142 170 // commn code for opening JSON object or JSON array:
jbe@142 171 json_import_open:
jbe@142 172 // limit nested levels:
jbe@142 173 if (level >= JSON_MAXDEPTH) {
jbe@142 174 lua_pushnil(L);
jbe@142 175 lua_pushliteral(L, "Too many nested JSON levels");
jbe@142 176 return 2;
jbe@142 177 }
jbe@142 178 // additional buffer overflow protection:
jbe@142 179 if (!lua_checkstack(L, LUA_MINSTACK))
jbe@142 180 return luaL_error(L, "Caught stack overflow in JSON import function (too many nested levels and stack size too small)");
jbe@136 181 // increment level:
jbe@121 182 level++;
jbe@142 183 // consume input character:
jbe@142 184 pos++;
jbe@121 185 goto json_import_loop;
jbe@136 186 // end of JSON object:
jbe@121 187 case '}':
jbe@136 188 // if end of JSON object is not expected here, then return an error:
jbe@124 189 if (mode != JSON_STATE_OBJECT_KEY && mode != JSON_STATE_OBJECT_SEPARATOR)
jbe@121 190 goto json_import_syntax_error;
jbe@136 191 // jump to common code for end of JSON object and JSON array:
jbe@121 192 goto json_import_close;
jbe@136 193 // end of JSON array:
jbe@121 194 case ']':
jbe@136 195 // if end of JSON array is not expected here, then return an error:
jbe@124 196 if (mode != JSON_STATE_ARRAY_VALUE && mode != JSON_STATE_ARRAY_SEPARATOR)
jbe@121 197 goto json_import_syntax_error;
jbe@140 198 // pop nil key/magic:
jbe@140 199 lua_pop(L, 1);
jbe@136 200 // continue with common code for end of JSON object and JSON array:
jbe@136 201 // common code for end of JSON object or JSON array:
jbe@121 202 json_import_close:
jbe@136 203 // consume input character:
jbe@121 204 pos++;
jbe@136 205 // pop shadow table:
jbe@136 206 lua_pop(L, 1);
jbe@136 207 // check if nested:
jbe@121 208 if (--level) {
jbe@136 209 // if nested, then check if outer(!) structure is an array or object:
jbe@140 210 if (lua_isnil(L, -2)) {
jbe@136 211 // select array value processing:
jbe@124 212 mode = JSON_STATE_ARRAY_VALUE;
jbe@121 213 } else {
jbe@136 214 // select object value processing:
jbe@124 215 mode = JSON_STATE_OBJECT_VALUE;
jbe@121 216 }
jbe@136 217 // store value in outer structure:
jbe@121 218 goto json_import_process_value;
jbe@121 219 }
jbe@136 220 // if not nested, then expect end of JSON document and continue with loop:
jbe@136 221 mode = JSON_STATE_END;
jbe@121 222 goto json_import_loop;
jbe@136 223 // key terminator:
jbe@121 224 case ':':
jbe@136 225 // if key terminator is not expected here, then return an error:
jbe@124 226 if (mode != JSON_STATE_OBJECT_KEY_TERMINATOR)
jbe@121 227 goto json_import_syntax_error;
jbe@136 228 // consume input character:
jbe@121 229 pos++;
jbe@136 230 // set state of parser and continue with loop:
jbe@124 231 mode = JSON_STATE_OBJECT_VALUE;
jbe@121 232 goto json_import_loop;
jbe@136 233 // value terminator (NOTE: trailing comma at end of value or key-value list is tolerated by this parser)
jbe@121 234 case ',':
jbe@136 235 // change parser state accordingly:
jbe@124 236 if (mode == JSON_STATE_OBJECT_SEPARATOR) {
jbe@124 237 mode = JSON_STATE_OBJECT_KEY;
jbe@124 238 } else if (mode == JSON_STATE_ARRAY_SEPARATOR) {
jbe@124 239 mode = JSON_STATE_ARRAY_VALUE;
jbe@121 240 } else {
jbe@136 241 // if value terminator is not expected here, then return an error:
jbe@136 242 goto json_import_syntax_error;
jbe@121 243 }
jbe@136 244 // consume input character:
jbe@121 245 pos++;
jbe@136 246 // continue with loop:
jbe@121 247 goto json_import_loop;
jbe@136 248 // string literal:
jbe@121 249 case '"':
jbe@136 250 // prepare buffer to decode string (with maximum possible length) and set write position to zero:
jbe@121 251 cbuf = luaL_buffinitsize(L, &luabuf, total-pos);
jbe@121 252 writepos = 0;
jbe@136 253 // consume quote character:
jbe@121 254 pos++;
jbe@136 255 // read next character until encountering end quote:
jbe@121 256 while ((c = str[pos++]) != '"') {
jbe@121 257 if (c == 0) {
jbe@136 258 // handle unexpected end-of-string:
jbe@121 259 goto json_import_unexpected_eof;
jbe@121 260 } else if (c < 32 || c == 127) {
jbe@136 261 // do not allow ASCII control characters:
jbe@136 262 // NOTE: illegal UTF-8 sequences and extended control characters are not sanitized
jbe@136 263 // by this parser to allow different encodings than Unicode
jbe@121 264 lua_pushnil(L);
jbe@121 265 lua_pushliteral(L, "Unexpected control character in JSON string");
jbe@121 266 return 2;
jbe@121 267 } else if (c == '\\') {
jbe@136 268 // read next char after backslash escape:
jbe@121 269 c = str[pos++];
jbe@121 270 switch (c) {
jbe@136 271 // unexpected end-of-string:
jbe@121 272 case 0:
jbe@121 273 goto json_import_unexpected_eof;
jbe@136 274 // unescaping of quotation mark, slash, and backslash:
jbe@121 275 case '"':
jbe@121 276 case '/':
jbe@121 277 case '\\':
jbe@121 278 cbuf[writepos++] = c;
jbe@121 279 break;
jbe@136 280 // unescaping of backspace:
jbe@121 281 case 'b':
jbe@121 282 cbuf[writepos++] = '\b';
jbe@121 283 break;
jbe@136 284 // unescaping of form-feed:
jbe@121 285 case 'f':
jbe@121 286 cbuf[writepos++] = '\f';
jbe@121 287 break;
jbe@136 288 // unescaping of new-line:
jbe@121 289 case 'n':
jbe@121 290 cbuf[writepos++] = '\n';
jbe@121 291 break;
jbe@136 292 // unescaping of carriage-return:
jbe@121 293 case 'r':
jbe@121 294 cbuf[writepos++] = '\r';
jbe@121 295 break;
jbe@136 296 // unescaping of tabulator:
jbe@121 297 case 't':
jbe@121 298 cbuf[writepos++] = '\t';
jbe@121 299 break;
jbe@136 300 // unescaping of UTF-16 characters
jbe@121 301 case 'u':
jbe@121 302 lua_pushnil(L);
jbe@121 303 lua_pushliteral(L, "JSON unicode escape sequences are not implemented yet"); // TODO
jbe@121 304 return 2;
jbe@136 305 // unexpected escape sequence:
jbe@121 306 default:
jbe@121 307 lua_pushnil(L);
jbe@121 308 lua_pushliteral(L, "Unexpected string escape sequence in JSON document");
jbe@121 309 return 2;
jbe@121 310 }
jbe@121 311 } else {
jbe@136 312 // normal character:
jbe@121 313 cbuf[writepos++] = c;
jbe@121 314 }
jbe@121 315 }
jbe@136 316 // process buffer to Lua string:
jbe@121 317 luaL_pushresultsize(&luabuf, writepos);
jbe@136 318 // continue with processing of decoded string:
jbe@121 319 goto json_import_process_value;
jbe@121 320 }
jbe@136 321 // process values whose type is is not deducible from a single character:
jbe@136 322 if ((c >= '0' && c <= '9') || c == '-' || c == '+') {
jbe@136 323 // numbers:
jbe@122 324 char *endptr;
jbe@122 325 double numval;
jbe@122 326 numval = strtod(str+pos, &endptr);
jbe@122 327 if (endptr == str+pos) goto json_import_syntax_error;
jbe@122 328 pos += endptr - (str+pos);
jbe@122 329 lua_pushnumber(L, numval);
jbe@122 330 } else if (!strncmp(str+pos, "true", 4)) {
jbe@136 331 // consume 4 input characters for "true":
jbe@121 332 pos += 4;
jbe@136 333 // put Lua true value on stack:
jbe@136 334 lua_pushboolean(L, 1);
jbe@121 335 } else if (!strncmp(str+pos, "false", 5)) {
jbe@136 336 // consume 5 input characters for "false":
jbe@121 337 pos += 5;
jbe@136 338 // put Lua false value on stack:
jbe@136 339 lua_pushboolean(L, 0);
jbe@121 340 } else if (!strncmp(str+pos, "null", 4)) {
jbe@136 341 // consume 4 input characters for "null":
jbe@136 342 pos += 4;
jbe@136 343 // put special null-marker on stack:
jbe@138 344 lua_pushvalue(L, json_import_nullmark_idx);
jbe@121 345 } else {
jbe@136 346 // all other cases are a syntax error:
jbe@121 347 goto json_import_syntax_error;
jbe@121 348 }
jbe@136 349 // process a decoded value or key value pair (expected on top of Lua stack):
jbe@136 350 json_import_process_value:
jbe@121 351 switch (mode) {
jbe@136 352 // an object key has been read:
jbe@124 353 case JSON_STATE_OBJECT_KEY:
jbe@136 354 // if an object key is not a string, then this is a syntax error:
jbe@121 355 if (lua_type(L, -1) != LUA_TSTRING) goto json_import_syntax_error;
jbe@136 356 // expect key terminator and continue with loop:
jbe@124 357 mode = JSON_STATE_OBJECT_KEY_TERMINATOR;
jbe@121 358 goto json_import_loop;
jbe@136 359 // a key value pair has been read:
jbe@124 360 case JSON_STATE_OBJECT_VALUE:
jbe@136 361 // store key value pair in outer shadow table:
jbe@130 362 lua_rawset(L, -3);
jbe@136 363 // expect value terminator (or end of object) and continue with loop:
jbe@124 364 mode = JSON_STATE_OBJECT_SEPARATOR;
jbe@121 365 goto json_import_loop;
jbe@136 366 // an array value has been read:
jbe@124 367 case JSON_STATE_ARRAY_VALUE:
jbe@136 368 // store value in outer shadow table:
jbe@140 369 lua_rawseti(L, -3, lua_rawlen(L, -3) + 1);
jbe@136 370 // expect value terminator (or end of object) and continue with loop:
jbe@124 371 mode = JSON_STATE_ARRAY_SEPARATOR;
jbe@121 372 goto json_import_loop;
jbe@136 373 // a single value has been read:
jbe@124 374 case JSON_STATE_VALUE:
jbe@136 375 // leave value on top of stack, expect end of JSON document, and continue with loop:
jbe@124 376 mode = JSON_STATE_END;
jbe@121 377 goto json_import_loop;
jbe@121 378 }
jbe@136 379 // syntax error handling (only reachable by goto statement):
jbe@136 380 json_import_syntax_error:
jbe@121 381 lua_pushnil(L);
jbe@121 382 lua_pushliteral(L, "Syntax error in JSON document");
jbe@121 383 return 2;
jbe@121 384 }
jbe@121 385
jbe@138 386 #define json_path_shadowtbl_idx 1
jbe@138 387 #define json_path_nullmark_idx 2
jbe@138 388 #define json_path_idxshift 2
jbe@138 389
jbe@137 390 // gets a value or its type from a JSON document (first argument)
jbe@137 391 // optionally using a path (variable number of keys after first argument):
jbe@137 392 static int json_path(lua_State *L, int type_mode) {
jbe@138 393 int stacktop;
jbe@138 394 int idx = 2 + json_path_idxshift;
jbe@138 395 // insert json_shadowtbl on stack at position 1:
jbe@138 396 json_regfetch(L, json_shadowtbl);
jbe@138 397 lua_insert(L, 1);
jbe@138 398 // insert json_nullmark on stack at position 2:
jbe@138 399 json_regfetch(L, json_nullmark);
jbe@138 400 lua_insert(L, 2);
jbe@137 401 // store number of arguments:
jbe@138 402 stacktop = lua_gettop(L);
jbe@137 403 // follow path, starting with first argument as "current value":
jbe@138 404 lua_pushvalue(L, 1 + json_path_idxshift);
jbe@137 405 // process each "path key":
jbe@138 406 while (idx <= stacktop) {
jbe@137 407 // if "current value" is nil, then the path cannot be walked and nil is returned:
jbe@137 408 if (lua_isnil(L, -1)) return 1;
jbe@137 409 // try to get shadow table of "current value":
jbe@130 410 lua_pushvalue(L, -1);
jbe@138 411 lua_rawget(L, json_path_shadowtbl_idx);
jbe@126 412 if (lua_isnil(L, -1)) {
jbe@137 413 // if no shadow table is found,
jbe@137 414 // drop nil from stack:
jbe@126 415 lua_pop(L, 1);
jbe@130 416 if (lua_type(L, -1) == LUA_TTABLE) {
jbe@137 417 // if "current value" is a table,
jbe@137 418 // get "next value" using the "path key":
jbe@130 419 lua_pushvalue(L, idx++);
jbe@130 420 lua_gettable(L, -2);
jbe@130 421 } else {
jbe@137 422 // if "current value" is not a table,
jbe@137 423 // then the path cannot be walked and nil is returned:
jbe@130 424 lua_pushnil(L);
jbe@137 425 return 1;
jbe@130 426 }
jbe@130 427 } else {
jbe@137 428 // if a shadow table is found,
jbe@137 429 // set "current value" to its shadow table:
jbe@130 430 lua_replace(L, -2);
jbe@137 431 // get "next value" using the "path key":
jbe@130 432 lua_pushvalue(L, idx++);
jbe@130 433 lua_rawget(L, -2);
jbe@126 434 }
jbe@137 435 // the "next value" replaces the "current value":
jbe@130 436 lua_replace(L, -2);
jbe@126 437 }
jbe@137 438 if (!type_mode) {
jbe@137 439 // if a value (and not its type) was requested,
jbe@137 440 // check if value is the null-marker, and store nil on top of Lua stack in that case:
jbe@138 441 if (lua_rawequal(L, -1, json_path_nullmark_idx)) lua_pushnil(L);
jbe@137 442 } else {
jbe@137 443 // if the type was requested,
jbe@137 444 // check if value is the null-marker:
jbe@138 445 if (lua_rawequal(L, -1, json_path_nullmark_idx)) {
jbe@137 446 // if yes, store string "null" on top of Lua stack:
jbe@130 447 lua_pushliteral(L, "null");
jbe@137 448 } else {
jbe@137 449 // otherwise,
jbe@138 450 // check if metatable indicates "object" or "array":
jbe@138 451 if (lua_getmetatable(L, -1)) {
jbe@138 452 json_regfetch(L, json_objectmt);
jbe@138 453 if (lua_rawequal(L, -2, -1)) {
jbe@138 454 // return string "object":
jbe@138 455 lua_pushliteral(L, "object");
jbe@138 456 return 1;
jbe@138 457 }
jbe@138 458 json_regfetch(L, json_arraymt);
jbe@138 459 if (lua_rawequal(L, -3, -1)) {
jbe@138 460 // return string "array":
jbe@138 461 lua_pushliteral(L, "array");
jbe@138 462 return 1;
jbe@138 463 }
jbe@138 464 lua_pop(L, 3);
jbe@138 465 }
jbe@138 466 // otherwise, get the Lua type:
jbe@138 467 lua_pushstring(L, lua_typename(L, lua_type(L, -1)));
jbe@126 468 }
jbe@126 469 }
jbe@137 470 // return the top most value on the Lua stack:
jbe@137 471 return 1;
jbe@130 472 }
jbe@130 473
jbe@137 474 // gets a value from a JSON document (first argument)
jbe@137 475 // optionally using a path (variable number of keys after first argument):
jbe@130 476 static int json_get(lua_State *L) {
jbe@137 477 return json_path(L, 0);
jbe@130 478 }
jbe@130 479
jbe@137 480 // gets a value's type from a JSON document (first argument)
jbe@137 481 // optionally using a path (variable number of keys after first argument):
jbe@130 482 static int json_type(lua_State *L) {
jbe@137 483 return json_path(L, 1);
jbe@130 484 }
jbe@130 485
jbe@137 486 // checks if a value in a JSON document (first argument) is null:
jbe@130 487 static int json_isnull(lua_State *L) {
jbe@137 488 const char *jsontype;
jbe@138 489 lua_pushcfunction(L, json_type);
jbe@137 490 lua_insert(L, 1);
jbe@137 491 lua_call(L, lua_gettop(L) - 1, 1);
jbe@137 492 jsontype = lua_tostring(L, -1);
jbe@137 493 if (jsontype && !strcmp(jsontype, "null")) lua_pushboolean(L, 1);
jbe@137 494 else lua_pushboolean(L, 0);
jbe@137 495 return 1;
jbe@130 496 }
jbe@130 497
jbe@138 498 #define json_setnull_unknownmt_idx 3
jbe@138 499 #define json_setnull_objectmt_idx 4
jbe@138 500 #define json_setnull_arraymt_idx 5
jbe@138 501 #define json_setnull_shadowtbl_idx 6
jbe@138 502
jbe@131 503 static int json_setnull(lua_State *L) {
jbe@138 504 // truncate stack to two elements:
jbe@131 505 lua_settop(L, 2);
jbe@138 506 // push json_unknownmt to stack position 3:
jbe@138 507 json_regfetch(L, json_unknownmt);
jbe@138 508 // push json_objectmt to stack position 4:
jbe@138 509 json_regfetch(L, json_objectmt);
jbe@138 510 // push json_arraymt to stack position 5:
jbe@138 511 json_regfetch(L, json_arraymt);
jbe@138 512 // push json_shadowtbl to stack position 6:
jbe@138 513 json_regfetch(L, json_shadowtbl);
jbe@138 514 //
jbe@138 515 lua_getmetatable(L, 1);
jbe@138 516 if (
jbe@138 517 !lua_rawequal(L, -1, json_setnull_unknownmt_idx) &&
jbe@138 518 !lua_rawequal(L, -1, json_setnull_objectmt_idx) &&
jbe@138 519 !lua_rawequal(L, -1, json_setnull_arraymt_idx)
jbe@138 520 ) {
jbe@138 521 lua_pushvalue(L, json_setnull_unknownmt_idx);
jbe@138 522 lua_setmetatable(L, 1);
jbe@138 523 }
jbe@131 524 lua_pushvalue(L, 1);
jbe@138 525 lua_rawget(L, json_setnull_shadowtbl_idx);
jbe@131 526 if (lua_isnil(L, -1)) {
jbe@131 527 lua_newtable(L);
jbe@131 528 lua_pushvalue(L, 1);
jbe@131 529 lua_pushvalue(L, -2);
jbe@138 530 lua_rawset(L, json_setnull_shadowtbl_idx);
jbe@131 531 }
jbe@131 532 lua_pushvalue(L, 2);
jbe@138 533 json_regfetch(L, json_nullmark);
jbe@131 534 lua_rawset(L, -3);
jbe@131 535 return 0;
jbe@131 536 }
jbe@131 537
jbe@130 538 static int json_len(lua_State *L) {
jbe@130 539 lua_settop(L, 1);
jbe@138 540 json_regfetch(L, json_shadowtbl);
jbe@130 541 lua_pushvalue(L, 1);
jbe@138 542 lua_rawget(L, -2);
jbe@138 543 lua_pushinteger(L, lua_rawlen(L, lua_isnil(L, -1) ? 1 : -1));
jbe@123 544 return 1;
jbe@123 545 }
jbe@123 546
jbe@141 547 #define json_index_nullmark_idx 3
jbe@141 548 #define json_index_shadowtbl_idx 4
jbe@141 549
jbe@130 550 static int json_index(lua_State *L) {
jbe@130 551 lua_settop(L, 2);
jbe@141 552 json_regfetch(L, json_nullmark); // on stack position 3
jbe@139 553 json_regfetch(L, json_shadowtbl);
jbe@130 554 lua_pushvalue(L, 1);
jbe@141 555 lua_rawget(L, json_index_shadowtbl_idx);
jbe@139 556 if (lua_isnil(L, -1)) return luaL_error(L, "Shadow table not found");
jbe@130 557 lua_pushvalue(L, 2);
jbe@130 558 lua_rawget(L, -2);
jbe@141 559 if (lua_rawequal(L, -1, json_index_nullmark_idx)) lua_pushnil(L);
jbe@127 560 return 1;
jbe@127 561 }
jbe@127 562
jbe@130 563 static int json_newindex(lua_State *L) {
jbe@130 564 lua_settop(L, 3);
jbe@139 565 json_regfetch(L, json_shadowtbl);
jbe@123 566 lua_pushvalue(L, 1);
jbe@143 567 lua_rawget(L, -2);
jbe@130 568 if (lua_isnil(L, -1)) return luaL_error(L, "Shadow table not found");
jbe@130 569 lua_replace(L, 1);
jbe@139 570 lua_settop(L, 3);
jbe@130 571 lua_rawset(L, 1);
jbe@121 572 return 1;
jbe@121 573 }
jbe@121 574
jbe@139 575 #define json_pairs_iterfunc_nullmark_idx 3
jbe@139 576 #define json_pairs_iterfunc_shadowtbl_idx 4
jbe@139 577
jbe@135 578 static int json_pairs_iterfunc(lua_State *L) {
jbe@135 579 lua_settop(L, 2);
jbe@139 580 json_regfetch(L, json_nullmark); // on stack position 3
jbe@139 581 json_regfetch(L, json_shadowtbl);
jbe@135 582 lua_pushvalue(L, 1);
jbe@139 583 lua_rawget(L, json_pairs_iterfunc_shadowtbl_idx);
jbe@135 584 if (lua_isnil(L, -1)) return luaL_error(L, "Shadow table not found");
jbe@135 585 lua_pushvalue(L, 2);
jbe@135 586 if (!lua_next(L, -2)) return 0;
jbe@139 587 if (lua_rawequal(L, -1, json_pairs_iterfunc_nullmark_idx)) {
jbe@135 588 lua_pop(L, 1);
jbe@135 589 lua_pushnil(L);
jbe@135 590 }
jbe@135 591 return 2;
jbe@135 592 }
jbe@135 593
jbe@135 594 static int json_pairs(lua_State *L) {
jbe@139 595 lua_pushcfunction(L, json_pairs_iterfunc);
jbe@135 596 lua_pushvalue(L, 1);
jbe@135 597 lua_pushnil(L);
jbe@135 598 return 3;
jbe@135 599 }
jbe@135 600
jbe@139 601 #define json_ipairs_iterfunc_nullmark_idx 3
jbe@139 602 #define json_ipairs_iterfunc_shadowtbl_idx 4
jbe@139 603
jbe@134 604 static int json_ipairs_iterfunc(lua_State *L) {
jbe@134 605 int idx;
jbe@134 606 lua_settop(L, 2);
jbe@139 607 json_regfetch(L, json_nullmark); // on stack position 3
jbe@139 608 json_regfetch(L, json_shadowtbl);
jbe@134 609 idx = lua_tointeger(L, 2) + 1;
jbe@134 610 lua_pushvalue(L, 1);
jbe@139 611 lua_rawget(L, json_ipairs_iterfunc_shadowtbl_idx);
jbe@134 612 if (lua_isnil(L, -1)) return luaL_error(L, "Shadow table not found");
jbe@134 613 lua_rawgeti(L, -1, idx);
jbe@134 614 if (lua_isnil(L, -1)) return 0;
jbe@134 615 lua_pushinteger(L, idx);
jbe@139 616 if (lua_rawequal(L, -2, json_ipairs_iterfunc_nullmark_idx)) lua_pushnil(L);
jbe@134 617 else lua_pushvalue(L, -2);
jbe@134 618 return 2;
jbe@134 619 }
jbe@134 620
jbe@134 621 static int json_ipairs(lua_State *L) {
jbe@139 622 lua_pushcfunction(L, json_ipairs_iterfunc);
jbe@134 623 lua_pushvalue(L, 1);
jbe@134 624 lua_pushinteger(L, 0);
jbe@134 625 return 3;
jbe@134 626 }
jbe@134 627
jbe@121 628 static const struct luaL_Reg json_module_functions[] = {
jbe@133 629 {"object", json_object},
jbe@133 630 {"array", json_array},
jbe@121 631 {"import", json_import},
jbe@130 632 {"get", json_get},
jbe@127 633 {"type", json_type},
jbe@123 634 {"isnull", json_isnull},
jbe@131 635 {"setnull", json_setnull},
jbe@121 636 {NULL, NULL}
jbe@121 637 };
jbe@121 638
jbe@126 639 static const struct luaL_Reg json_metatable_functions[] = {
jbe@130 640 {"__len", json_len},
jbe@130 641 {"__index", json_index},
jbe@130 642 {"__newindex", json_newindex},
jbe@135 643 {"__pairs", json_pairs},
jbe@134 644 {"__ipairs", json_ipairs},
jbe@126 645 {NULL, NULL}
jbe@126 646 };
jbe@126 647
jbe@121 648 int luaopen_json(lua_State *L) {
jbe@126 649 lua_settop(L, 0);
jbe@138 650 lua_newtable(L); // library
jbe@138 651 lua_newtable(L);
jbe@138 652 luaL_setfuncs(L, json_metatable_functions, 0);
jbe@138 653 json_regstore(L, json_unknownmt);
jbe@138 654 lua_setfield(L, 1, "ambiguous_mt");
jbe@138 655 lua_newtable(L);
jbe@138 656 luaL_setfuncs(L, json_metatable_functions, 0);
jbe@138 657 json_regstore(L, json_objectmt);
jbe@138 658 lua_setfield(L, 1, "object_mt");
jbe@138 659 lua_newtable(L);
jbe@138 660 luaL_setfuncs(L, json_metatable_functions, 0);
jbe@138 661 json_regstore(L, json_arraymt);
jbe@138 662 lua_setfield(L, 1, "array_mt");
jbe@138 663 lua_newtable(L); // ephemeron table to store shadow tables for each JSON object/array to allow NULL values returned as nil
jbe@138 664 lua_newtable(L); // metatable for ephemeron table
jbe@121 665 lua_pushliteral(L, "__mode");
jbe@121 666 lua_pushliteral(L, "k");
jbe@138 667 lua_rawset(L, -3);
jbe@138 668 lua_setmetatable(L, -2);
jbe@138 669 json_regstore(L, json_shadowtbl);
jbe@138 670 lua_newtable(L);
jbe@138 671 json_regstore(L, json_nullmark);
jbe@138 672 lua_settop(L, 1);
jbe@138 673 luaL_setfuncs(L, json_module_functions, 0);
jbe@121 674 return 1;
jbe@121 675 }

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