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annotate libraries/json/json.c @ 139:a4ce17051eff

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Work on JSON library (problem with stack still existent)
author jbe
date Tue Jul 29 22:02:01 2014 +0200 (2014-07-29)
parents 8a533f370038
children 641619d3fcb1
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@137 6 #define JSON_UPVAL_LIBRARY lua_upvalueindex(1)
jbe@137 7 #define JSON_UPVAL_NULLMARK lua_upvalueindex(2)
jbe@137 8 #define JSON_UPVAL_SHADOWTBL lua_upvalueindex(3)
jbe@137 9 #define JSON_UPVAL_TYPES lua_upvalueindex(4)
jbe@137 10 #define JSON_UPVAL_METATABLE lua_upvalueindex(5)
jbe@137 11 #define JSON_UPVAL_PAIRS_ITERFUNC lua_upvalueindex(6)
jbe@137 12 #define JSON_UPVAL_IPAIRS_ITERFUNC lua_upvalueindex(7)
jbe@123 13
jbe@138 14 #define JSON_REGENT static char
jbe@138 15 #define JSON_REGREF void *
jbe@138 16
jbe@138 17 JSON_REGENT json_nullmark;
jbe@138 18 JSON_REGENT json_shadowtbl;
jbe@138 19 JSON_REGENT json_unknownmt;
jbe@138 20 JSON_REGENT json_objectmt;
jbe@138 21 JSON_REGENT json_arraymt;
jbe@138 22
jbe@138 23 #define json_regfetch(L, x) (lua_pushlightuserdata((L), &(x)), lua_rawget((L), LUA_REGISTRYINDEX))
jbe@138 24
jbe@138 25 #define json_regstore(L, x) (lua_pushlightuserdata(L, &(x)), lua_pushvalue(L, -2), lua_rawset(L, LUA_REGISTRYINDEX));
jbe@138 26
jbe@136 27 // marks a table as JSON object or JSON array:
jbe@136 28 // (returns its modified argument or a new table if argument is nil)
jbe@138 29 static int json_mark(lua_State *L, JSON_REGREF mt) {
jbe@136 30 // if argument is nil, then create new table:
jbe@136 31 if (lua_isnoneornil(L, 1)) {
jbe@136 32 lua_settop(L, 0);
jbe@136 33 lua_newtable(L);
jbe@136 34 // skip testing of existing shadow table:
jbe@136 35 goto json_object_create_shadow_table;
jbe@136 36 }
jbe@138 37 // check if shadow table already exists:
jbe@138 38 json_regfetch(L, json_shadowtbl);
jbe@136 39 lua_pushvalue(L, 1);
jbe@138 40 lua_rawget(L, -2);
jbe@136 41 if (lua_isnil(L, -1)) {
jbe@136 42 json_object_create_shadow_table:
jbe@136 43 // set shadow table:
jbe@136 44 lua_pushvalue(L, 1);
jbe@136 45 lua_newtable(L);
jbe@138 46 lua_rawset(L, -4);
jbe@136 47 }
jbe@138 48 // discard everything but table to return:
jbe@138 49 lua_settop(L, 1);
jbe@136 50 // set metatable:
jbe@138 51 json_regfetch(L, mt);
jbe@136 52 lua_setmetatable(L, 1);
jbe@138 53 // return table:
jbe@136 54 return 1;
jbe@136 55 }
jbe@136 56
jbe@136 57 // marks a table as JSON object:
jbe@136 58 // (returns its modified argument or a new table if argument is nil)
jbe@136 59 static int json_object(lua_State *L) {
jbe@138 60 return json_mark(L, &json_objectmt);
jbe@136 61 }
jbe@136 62
jbe@136 63 // marks a table as JSON array:
jbe@136 64 // (returns its modified argument or a new table if argument is nil)
jbe@136 65 static int json_array(lua_State *L) {
jbe@138 66 return json_mark(L, &json_arraymt);
jbe@136 67 }
jbe@136 68
jbe@124 69 #define JSON_STATE_VALUE 0
jbe@124 70 #define JSON_STATE_OBJECT_KEY 1
jbe@124 71 #define JSON_STATE_OBJECT_KEY_TERMINATOR 2
jbe@124 72 #define JSON_STATE_OBJECT_VALUE 3
jbe@124 73 #define JSON_STATE_OBJECT_SEPARATOR 4
jbe@124 74 #define JSON_STATE_ARRAY_VALUE 5
jbe@124 75 #define JSON_STATE_ARRAY_SEPARATOR 6
jbe@124 76 #define JSON_STATE_END 7
jbe@121 77
jbe@138 78 #define json_import_objectmt_idx 2
jbe@138 79 #define json_import_arraymt_idx 3
jbe@138 80 #define json_import_shadowtbl_idx 4
jbe@138 81 #define json_import_nullmark_idx 5
jbe@138 82
jbe@136 83 // decodes a JSON document:
jbe@121 84 static int json_import(lua_State *L) {
jbe@136 85 const char *str; // string to parse
jbe@136 86 size_t total; // total length of string to parse
jbe@136 87 size_t pos = 0; // current position in string to parse
jbe@136 88 size_t level = 0; // nested levels of objects/arrays currently being processed
jbe@136 89 int mode = JSON_STATE_VALUE; // state of parser
jbe@136 90 char c; // variable to store a single character to be processed
jbe@136 91 luaL_Buffer luabuf; // Lua buffer to decode (possibly escaped) strings
jbe@136 92 char *cbuf; // C buffer to decode (possibly escaped) strings
jbe@136 93 size_t writepos; // write position of decoded strings in C buffer
jbe@138 94 // limit stack to 1 element:
jbe@138 95 lua_settop(L, 1);
jbe@138 96 // push json_objectmt on stack position 2:
jbe@138 97 json_regfetch(L, json_objectmt);
jbe@138 98 // push json_arraymt on stack position 3:
jbe@138 99 json_regfetch(L, json_arraymt);
jbe@138 100 // push json_shadowtbl on stack position 4:
jbe@138 101 json_regfetch(L, json_shadowtbl);
jbe@138 102 // push json_nullmark on stack position 5:
jbe@138 103 json_regfetch(L, json_nullmark);
jbe@136 104 // require string as first argument:
jbe@136 105 str = luaL_checklstring(L, 1, &total);
jbe@136 106 // if string contains a NULL byte, this is a syntax error
jbe@136 107 if (strlen(str) != total) goto json_import_syntax_error;
jbe@136 108 // main loop of parser:
jbe@136 109 json_import_loop:
jbe@136 110 // skip whitespace and store next character in variable 'c':
jbe@121 111 while (c = str[pos], c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == '\f') pos++;
jbe@136 112 // switch statement to handle certain (single) characters:
jbe@121 113 switch (c) {
jbe@136 114 // handle end of JSON document:
jbe@121 115 case 0:
jbe@136 116 // if end of JSON document was expected, then return top element of stack as result:
jbe@124 117 if (mode == JSON_STATE_END) return 1;
jbe@136 118 // otherwise, the JSON document was malformed:
jbe@121 119 json_import_unexpected_eof:
jbe@121 120 lua_pushnil(L);
jbe@121 121 if (level == 0) lua_pushliteral(L, "Empty string");
jbe@121 122 else lua_pushliteral(L, "Unexpected end of JSON document");
jbe@121 123 return 2;
jbe@136 124 // new JSON object:
jbe@121 125 case '{':
jbe@136 126 // if a JSON object is not expected here, then return an error:
jbe@124 127 if (mode != JSON_STATE_VALUE && mode != JSON_STATE_OBJECT_VALUE && mode != JSON_STATE_ARRAY_VALUE)
jbe@121 128 goto json_import_syntax_error;
jbe@136 129 // consume input character:
jbe@121 130 pos++;
jbe@136 131 // create JSON object on stack:
jbe@136 132 lua_newtable(L);
jbe@136 133 // set metatable of JSON object:
jbe@138 134 lua_pushvalue(L, json_import_objectmt_idx);
jbe@125 135 lua_setmetatable(L, -2);
jbe@136 136 // create internal shadow table on stack:
jbe@136 137 lua_newtable(L);
jbe@138 138 // register internal shadow table (and cleanup stack afterwards):
jbe@123 139 lua_pushvalue(L, -2);
jbe@123 140 lua_pushvalue(L, -2);
jbe@138 141 lua_rawset(L, json_import_shadowtbl_idx);
jbe@136 142 // increment level:
jbe@121 143 level++;
jbe@136 144 // expect object key (or end of object) and continue with loop:
jbe@136 145 mode = JSON_STATE_OBJECT_KEY;
jbe@121 146 goto json_import_loop;
jbe@136 147 // new JSON array:
jbe@121 148 case '[':
jbe@136 149 // if a JSON array is not expected here, then return an error:
jbe@124 150 if (mode != JSON_STATE_VALUE && mode != JSON_STATE_OBJECT_VALUE && mode != JSON_STATE_ARRAY_VALUE)
jbe@121 151 goto json_import_syntax_error;
jbe@136 152 // consume input character:
jbe@121 153 pos++;
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@136 165 // increment level:
jbe@121 166 level++;
jbe@136 167 // expect array value (or end of array) and continue with loop:
jbe@136 168 mode = JSON_STATE_ARRAY_VALUE;
jbe@121 169 goto json_import_loop;
jbe@136 170 // end of JSON object:
jbe@121 171 case '}':
jbe@136 172 // if end of JSON object is not expected here, then return an error:
jbe@124 173 if (mode != JSON_STATE_OBJECT_KEY && mode != JSON_STATE_OBJECT_SEPARATOR)
jbe@121 174 goto json_import_syntax_error;
jbe@136 175 // jump to common code for end of JSON object and JSON array:
jbe@121 176 goto json_import_close;
jbe@136 177 // end of JSON array:
jbe@121 178 case ']':
jbe@136 179 // if end of JSON array is not expected here, then return an error:
jbe@124 180 if (mode != JSON_STATE_ARRAY_VALUE && mode != JSON_STATE_ARRAY_SEPARATOR)
jbe@121 181 goto json_import_syntax_error;
jbe@136 182 // continue with common code for end of JSON object and JSON array:
jbe@136 183 // common code for end of JSON object or JSON array:
jbe@121 184 json_import_close:
jbe@136 185 // consume input character:
jbe@121 186 pos++;
jbe@136 187 // pop shadow table:
jbe@136 188 lua_pop(L, 1);
jbe@136 189 // check if nested:
jbe@121 190 if (--level) {
jbe@136 191 // if nested, then check if outer(!) structure is an array or object:
jbe@139 192 lua_getmetatable(L, c == '}' ? -4 : -3); // TODO: this approach doesn't work, because objects have an extra key on stack!
jbe@139 193 if (lua_rawequal(L, -1, json_import_arraymt_idx)) {
jbe@136 194 // select array value processing:
jbe@139 195 fprintf(stderr, "DEBUG: Process array\n");
jbe@124 196 mode = JSON_STATE_ARRAY_VALUE;
jbe@121 197 } else {
jbe@136 198 // select object value processing:
jbe@139 199 fprintf(stderr, "DEBUG: Process object\n");
jbe@124 200 mode = JSON_STATE_OBJECT_VALUE;
jbe@121 201 }
jbe@138 202 // pop metatable from stack (that was needed for type distinction):
jbe@136 203 lua_pop(L, 1);
jbe@136 204 // store value in outer structure:
jbe@121 205 goto json_import_process_value;
jbe@121 206 }
jbe@136 207 // if not nested, then expect end of JSON document and continue with loop:
jbe@139 208 fprintf(stderr, "DEBUG: Process document\n");
jbe@136 209 mode = JSON_STATE_END;
jbe@121 210 goto json_import_loop;
jbe@136 211 // key terminator:
jbe@121 212 case ':':
jbe@136 213 // if key terminator is not expected here, then return an error:
jbe@124 214 if (mode != JSON_STATE_OBJECT_KEY_TERMINATOR)
jbe@121 215 goto json_import_syntax_error;
jbe@136 216 // consume input character:
jbe@121 217 pos++;
jbe@136 218 // set state of parser and continue with loop:
jbe@124 219 mode = JSON_STATE_OBJECT_VALUE;
jbe@121 220 goto json_import_loop;
jbe@136 221 // value terminator (NOTE: trailing comma at end of value or key-value list is tolerated by this parser)
jbe@121 222 case ',':
jbe@136 223 // change parser state accordingly:
jbe@124 224 if (mode == JSON_STATE_OBJECT_SEPARATOR) {
jbe@124 225 mode = JSON_STATE_OBJECT_KEY;
jbe@124 226 } else if (mode == JSON_STATE_ARRAY_SEPARATOR) {
jbe@124 227 mode = JSON_STATE_ARRAY_VALUE;
jbe@121 228 } else {
jbe@136 229 // if value terminator is not expected here, then return an error:
jbe@136 230 goto json_import_syntax_error;
jbe@121 231 }
jbe@136 232 // consume input character:
jbe@121 233 pos++;
jbe@136 234 // continue with loop:
jbe@121 235 goto json_import_loop;
jbe@136 236 // string literal:
jbe@121 237 case '"':
jbe@136 238 // prepare buffer to decode string (with maximum possible length) and set write position to zero:
jbe@121 239 cbuf = luaL_buffinitsize(L, &luabuf, total-pos);
jbe@121 240 writepos = 0;
jbe@136 241 // consume quote character:
jbe@121 242 pos++;
jbe@136 243 // read next character until encountering end quote:
jbe@121 244 while ((c = str[pos++]) != '"') {
jbe@121 245 if (c == 0) {
jbe@136 246 // handle unexpected end-of-string:
jbe@121 247 goto json_import_unexpected_eof;
jbe@121 248 } else if (c < 32 || c == 127) {
jbe@136 249 // do not allow ASCII control characters:
jbe@136 250 // NOTE: illegal UTF-8 sequences and extended control characters are not sanitized
jbe@136 251 // by this parser to allow different encodings than Unicode
jbe@121 252 lua_pushnil(L);
jbe@121 253 lua_pushliteral(L, "Unexpected control character in JSON string");
jbe@121 254 return 2;
jbe@121 255 } else if (c == '\\') {
jbe@136 256 // read next char after backslash escape:
jbe@121 257 c = str[pos++];
jbe@121 258 switch (c) {
jbe@136 259 // unexpected end-of-string:
jbe@121 260 case 0:
jbe@121 261 goto json_import_unexpected_eof;
jbe@136 262 // unescaping of quotation mark, slash, and backslash:
jbe@121 263 case '"':
jbe@121 264 case '/':
jbe@121 265 case '\\':
jbe@121 266 cbuf[writepos++] = c;
jbe@121 267 break;
jbe@136 268 // unescaping of backspace:
jbe@121 269 case 'b':
jbe@121 270 cbuf[writepos++] = '\b';
jbe@121 271 break;
jbe@136 272 // unescaping of form-feed:
jbe@121 273 case 'f':
jbe@121 274 cbuf[writepos++] = '\f';
jbe@121 275 break;
jbe@136 276 // unescaping of new-line:
jbe@121 277 case 'n':
jbe@121 278 cbuf[writepos++] = '\n';
jbe@121 279 break;
jbe@136 280 // unescaping of carriage-return:
jbe@121 281 case 'r':
jbe@121 282 cbuf[writepos++] = '\r';
jbe@121 283 break;
jbe@136 284 // unescaping of tabulator:
jbe@121 285 case 't':
jbe@121 286 cbuf[writepos++] = '\t';
jbe@121 287 break;
jbe@136 288 // unescaping of UTF-16 characters
jbe@121 289 case 'u':
jbe@121 290 lua_pushnil(L);
jbe@121 291 lua_pushliteral(L, "JSON unicode escape sequences are not implemented yet"); // TODO
jbe@121 292 return 2;
jbe@136 293 // unexpected escape sequence:
jbe@121 294 default:
jbe@121 295 lua_pushnil(L);
jbe@121 296 lua_pushliteral(L, "Unexpected string escape sequence in JSON document");
jbe@121 297 return 2;
jbe@121 298 }
jbe@121 299 } else {
jbe@136 300 // normal character:
jbe@121 301 cbuf[writepos++] = c;
jbe@121 302 }
jbe@121 303 }
jbe@136 304 // process buffer to Lua string:
jbe@121 305 luaL_pushresultsize(&luabuf, writepos);
jbe@136 306 // continue with processing of decoded string:
jbe@121 307 goto json_import_process_value;
jbe@121 308 }
jbe@136 309 // process values whose type is is not deducible from a single character:
jbe@136 310 if ((c >= '0' && c <= '9') || c == '-' || c == '+') {
jbe@136 311 // numbers:
jbe@122 312 char *endptr;
jbe@122 313 double numval;
jbe@122 314 numval = strtod(str+pos, &endptr);
jbe@122 315 if (endptr == str+pos) goto json_import_syntax_error;
jbe@122 316 pos += endptr - (str+pos);
jbe@122 317 lua_pushnumber(L, numval);
jbe@122 318 } else if (!strncmp(str+pos, "true", 4)) {
jbe@136 319 // consume 4 input characters for "true":
jbe@121 320 pos += 4;
jbe@136 321 // put Lua true value on stack:
jbe@136 322 lua_pushboolean(L, 1);
jbe@121 323 } else if (!strncmp(str+pos, "false", 5)) {
jbe@136 324 // consume 5 input characters for "false":
jbe@121 325 pos += 5;
jbe@136 326 // put Lua false value on stack:
jbe@136 327 lua_pushboolean(L, 0);
jbe@121 328 } else if (!strncmp(str+pos, "null", 4)) {
jbe@136 329 // consume 4 input characters for "null":
jbe@136 330 pos += 4;
jbe@136 331 // put special null-marker on stack:
jbe@138 332 lua_pushvalue(L, json_import_nullmark_idx);
jbe@121 333 } else {
jbe@136 334 // all other cases are a syntax error:
jbe@121 335 goto json_import_syntax_error;
jbe@121 336 }
jbe@136 337 // process a decoded value or key value pair (expected on top of Lua stack):
jbe@136 338 json_import_process_value:
jbe@121 339 switch (mode) {
jbe@136 340 // an object key has been read:
jbe@124 341 case JSON_STATE_OBJECT_KEY:
jbe@136 342 // if an object key is not a string, then this is a syntax error:
jbe@121 343 if (lua_type(L, -1) != LUA_TSTRING) goto json_import_syntax_error;
jbe@136 344 // expect key terminator and continue with loop:
jbe@124 345 mode = JSON_STATE_OBJECT_KEY_TERMINATOR;
jbe@121 346 goto json_import_loop;
jbe@136 347 // a key value pair has been read:
jbe@124 348 case JSON_STATE_OBJECT_VALUE:
jbe@136 349 // store key value pair in outer shadow table:
jbe@130 350 lua_rawset(L, -3);
jbe@136 351 // expect value terminator (or end of object) and continue with loop:
jbe@124 352 mode = JSON_STATE_OBJECT_SEPARATOR;
jbe@121 353 goto json_import_loop;
jbe@136 354 // an array value has been read:
jbe@124 355 case JSON_STATE_ARRAY_VALUE:
jbe@136 356 // store value in outer shadow table:
jbe@136 357 lua_rawseti(L, -2, lua_rawlen(L, -2) + 1);
jbe@136 358 // expect value terminator (or end of object) and continue with loop:
jbe@124 359 mode = JSON_STATE_ARRAY_SEPARATOR;
jbe@121 360 goto json_import_loop;
jbe@136 361 // a single value has been read:
jbe@124 362 case JSON_STATE_VALUE:
jbe@136 363 // leave value on top of stack, expect end of JSON document, and continue with loop:
jbe@124 364 mode = JSON_STATE_END;
jbe@121 365 goto json_import_loop;
jbe@121 366 }
jbe@136 367 // syntax error handling (only reachable by goto statement):
jbe@136 368 json_import_syntax_error:
jbe@121 369 lua_pushnil(L);
jbe@121 370 lua_pushliteral(L, "Syntax error in JSON document");
jbe@121 371 return 2;
jbe@121 372 }
jbe@121 373
jbe@138 374 #define json_path_shadowtbl_idx 1
jbe@138 375 #define json_path_nullmark_idx 2
jbe@138 376 #define json_path_idxshift 2
jbe@138 377
jbe@137 378 // gets a value or its type from a JSON document (first argument)
jbe@137 379 // optionally using a path (variable number of keys after first argument):
jbe@137 380 static int json_path(lua_State *L, int type_mode) {
jbe@138 381 int stacktop;
jbe@138 382 int idx = 2 + json_path_idxshift;
jbe@138 383 // insert json_shadowtbl on stack at position 1:
jbe@138 384 json_regfetch(L, json_shadowtbl);
jbe@138 385 lua_insert(L, 1);
jbe@138 386 // insert json_nullmark on stack at position 2:
jbe@138 387 json_regfetch(L, json_nullmark);
jbe@138 388 lua_insert(L, 2);
jbe@137 389 // store number of arguments:
jbe@138 390 stacktop = lua_gettop(L);
jbe@137 391 // follow path, starting with first argument as "current value":
jbe@138 392 lua_pushvalue(L, 1 + json_path_idxshift);
jbe@137 393 // process each "path key":
jbe@138 394 while (idx <= stacktop) {
jbe@137 395 // if "current value" is nil, then the path cannot be walked and nil is returned:
jbe@137 396 if (lua_isnil(L, -1)) return 1;
jbe@137 397 // try to get shadow table of "current value":
jbe@130 398 lua_pushvalue(L, -1);
jbe@138 399 lua_rawget(L, json_path_shadowtbl_idx);
jbe@126 400 if (lua_isnil(L, -1)) {
jbe@137 401 // if no shadow table is found,
jbe@137 402 // drop nil from stack:
jbe@126 403 lua_pop(L, 1);
jbe@130 404 if (lua_type(L, -1) == LUA_TTABLE) {
jbe@137 405 // if "current value" is a table,
jbe@137 406 // get "next value" using the "path key":
jbe@130 407 lua_pushvalue(L, idx++);
jbe@130 408 lua_gettable(L, -2);
jbe@130 409 } else {
jbe@137 410 // if "current value" is not a table,
jbe@137 411 // then the path cannot be walked and nil is returned:
jbe@130 412 lua_pushnil(L);
jbe@137 413 return 1;
jbe@130 414 }
jbe@130 415 } else {
jbe@137 416 // if a shadow table is found,
jbe@137 417 // set "current value" to its shadow table:
jbe@130 418 lua_replace(L, -2);
jbe@137 419 // get "next value" using the "path key":
jbe@130 420 lua_pushvalue(L, idx++);
jbe@130 421 lua_rawget(L, -2);
jbe@126 422 }
jbe@137 423 // the "next value" replaces the "current value":
jbe@130 424 lua_replace(L, -2);
jbe@126 425 }
jbe@137 426 if (!type_mode) {
jbe@137 427 // if a value (and not its type) was requested,
jbe@137 428 // check if value is the null-marker, and store nil on top of Lua stack in that case:
jbe@138 429 if (lua_rawequal(L, -1, json_path_nullmark_idx)) lua_pushnil(L);
jbe@137 430 } else {
jbe@137 431 // if the type was requested,
jbe@137 432 // check if value is the null-marker:
jbe@138 433 if (lua_rawequal(L, -1, json_path_nullmark_idx)) {
jbe@137 434 // if yes, store string "null" on top of Lua stack:
jbe@130 435 lua_pushliteral(L, "null");
jbe@137 436 } else {
jbe@137 437 // otherwise,
jbe@138 438 // check if metatable indicates "object" or "array":
jbe@138 439 if (lua_getmetatable(L, -1)) {
jbe@138 440 json_regfetch(L, json_objectmt);
jbe@138 441 if (lua_rawequal(L, -2, -1)) {
jbe@138 442 // return string "object":
jbe@138 443 lua_pushliteral(L, "object");
jbe@138 444 return 1;
jbe@138 445 }
jbe@138 446 json_regfetch(L, json_arraymt);
jbe@138 447 if (lua_rawequal(L, -3, -1)) {
jbe@138 448 // return string "array":
jbe@138 449 lua_pushliteral(L, "array");
jbe@138 450 return 1;
jbe@138 451 }
jbe@138 452 lua_pop(L, 3);
jbe@138 453 }
jbe@138 454 // otherwise, get the Lua type:
jbe@138 455 lua_pushstring(L, lua_typename(L, lua_type(L, -1)));
jbe@126 456 }
jbe@126 457 }
jbe@137 458 // return the top most value on the Lua stack:
jbe@137 459 return 1;
jbe@130 460 }
jbe@130 461
jbe@137 462 // gets a value from a JSON document (first argument)
jbe@137 463 // optionally using a path (variable number of keys after first argument):
jbe@130 464 static int json_get(lua_State *L) {
jbe@137 465 return json_path(L, 0);
jbe@130 466 }
jbe@130 467
jbe@137 468 // gets a value's type from a JSON document (first argument)
jbe@137 469 // optionally using a path (variable number of keys after first argument):
jbe@130 470 static int json_type(lua_State *L) {
jbe@137 471 return json_path(L, 1);
jbe@130 472 }
jbe@130 473
jbe@137 474 // checks if a value in a JSON document (first argument) is null:
jbe@130 475 static int json_isnull(lua_State *L) {
jbe@137 476 const char *jsontype;
jbe@138 477 lua_pushcfunction(L, json_type);
jbe@137 478 lua_insert(L, 1);
jbe@137 479 lua_call(L, lua_gettop(L) - 1, 1);
jbe@137 480 jsontype = lua_tostring(L, -1);
jbe@137 481 if (jsontype && !strcmp(jsontype, "null")) lua_pushboolean(L, 1);
jbe@137 482 else lua_pushboolean(L, 0);
jbe@137 483 return 1;
jbe@130 484 }
jbe@130 485
jbe@138 486 #define json_setnull_unknownmt_idx 3
jbe@138 487 #define json_setnull_objectmt_idx 4
jbe@138 488 #define json_setnull_arraymt_idx 5
jbe@138 489 #define json_setnull_shadowtbl_idx 6
jbe@138 490
jbe@131 491 static int json_setnull(lua_State *L) {
jbe@138 492 // truncate stack to two elements:
jbe@131 493 lua_settop(L, 2);
jbe@138 494 // push json_unknownmt to stack position 3:
jbe@138 495 json_regfetch(L, json_unknownmt);
jbe@138 496 // push json_objectmt to stack position 4:
jbe@138 497 json_regfetch(L, json_objectmt);
jbe@138 498 // push json_arraymt to stack position 5:
jbe@138 499 json_regfetch(L, json_arraymt);
jbe@138 500 // push json_shadowtbl to stack position 6:
jbe@138 501 json_regfetch(L, json_shadowtbl);
jbe@138 502 //
jbe@138 503 lua_getmetatable(L, 1);
jbe@138 504 if (
jbe@138 505 !lua_rawequal(L, -1, json_setnull_unknownmt_idx) &&
jbe@138 506 !lua_rawequal(L, -1, json_setnull_objectmt_idx) &&
jbe@138 507 !lua_rawequal(L, -1, json_setnull_arraymt_idx)
jbe@138 508 ) {
jbe@138 509 lua_pushvalue(L, json_setnull_unknownmt_idx);
jbe@138 510 lua_setmetatable(L, 1);
jbe@138 511 }
jbe@131 512 lua_pushvalue(L, 1);
jbe@138 513 lua_rawget(L, json_setnull_shadowtbl_idx);
jbe@131 514 if (lua_isnil(L, -1)) {
jbe@131 515 lua_newtable(L);
jbe@131 516 lua_pushvalue(L, 1);
jbe@131 517 lua_pushvalue(L, -2);
jbe@138 518 lua_rawset(L, json_setnull_shadowtbl_idx);
jbe@131 519 }
jbe@131 520 lua_pushvalue(L, 2);
jbe@138 521 json_regfetch(L, json_nullmark);
jbe@131 522 lua_rawset(L, -3);
jbe@131 523 return 0;
jbe@131 524 }
jbe@131 525
jbe@130 526 static int json_len(lua_State *L) {
jbe@130 527 lua_settop(L, 1);
jbe@138 528 json_regfetch(L, json_shadowtbl);
jbe@130 529 lua_pushvalue(L, 1);
jbe@138 530 lua_rawget(L, -2);
jbe@138 531 lua_pushinteger(L, lua_rawlen(L, lua_isnil(L, -1) ? 1 : -1));
jbe@123 532 return 1;
jbe@123 533 }
jbe@123 534
jbe@130 535 static int json_index(lua_State *L) {
jbe@130 536 lua_settop(L, 2);
jbe@139 537 json_regfetch(L, json_shadowtbl);
jbe@130 538 lua_pushvalue(L, 1);
jbe@139 539 lua_rawget(L, -2);
jbe@139 540 if (lua_isnil(L, -1)) return luaL_error(L, "Shadow table not found");
jbe@130 541 lua_pushvalue(L, 2);
jbe@130 542 lua_rawget(L, -2);
jbe@130 543 if (lua_rawequal(L, -1, JSON_UPVAL_NULLMARK)) lua_pushnil(L);
jbe@127 544 return 1;
jbe@127 545 }
jbe@127 546
jbe@130 547 static int json_newindex(lua_State *L) {
jbe@130 548 lua_settop(L, 3);
jbe@139 549 json_regfetch(L, json_shadowtbl);
jbe@123 550 lua_pushvalue(L, 1);
jbe@139 551 lua_rawget(L, -1);
jbe@130 552 if (lua_isnil(L, -1)) return luaL_error(L, "Shadow table not found");
jbe@130 553 lua_replace(L, 1);
jbe@139 554 lua_settop(L, 3);
jbe@130 555 lua_rawset(L, 1);
jbe@121 556 return 1;
jbe@121 557 }
jbe@121 558
jbe@139 559 #define json_pairs_iterfunc_nullmark_idx 3
jbe@139 560 #define json_pairs_iterfunc_shadowtbl_idx 4
jbe@139 561
jbe@135 562 static int json_pairs_iterfunc(lua_State *L) {
jbe@135 563 lua_settop(L, 2);
jbe@139 564 json_regfetch(L, json_nullmark); // on stack position 3
jbe@139 565 json_regfetch(L, json_shadowtbl);
jbe@135 566 lua_pushvalue(L, 1);
jbe@139 567 lua_rawget(L, json_pairs_iterfunc_shadowtbl_idx);
jbe@135 568 if (lua_isnil(L, -1)) return luaL_error(L, "Shadow table not found");
jbe@135 569 lua_pushvalue(L, 2);
jbe@135 570 if (!lua_next(L, -2)) return 0;
jbe@139 571 if (lua_rawequal(L, -1, json_pairs_iterfunc_nullmark_idx)) {
jbe@135 572 lua_pop(L, 1);
jbe@135 573 lua_pushnil(L);
jbe@135 574 }
jbe@135 575 return 2;
jbe@135 576 }
jbe@135 577
jbe@135 578 static int json_pairs(lua_State *L) {
jbe@139 579 lua_pushcfunction(L, json_pairs_iterfunc);
jbe@135 580 lua_pushvalue(L, 1);
jbe@135 581 lua_pushnil(L);
jbe@135 582 return 3;
jbe@135 583 }
jbe@135 584
jbe@139 585 #define json_ipairs_iterfunc_nullmark_idx 3
jbe@139 586 #define json_ipairs_iterfunc_shadowtbl_idx 4
jbe@139 587
jbe@134 588 static int json_ipairs_iterfunc(lua_State *L) {
jbe@134 589 int idx;
jbe@134 590 lua_settop(L, 2);
jbe@139 591 json_regfetch(L, json_nullmark); // on stack position 3
jbe@139 592 json_regfetch(L, json_shadowtbl);
jbe@134 593 idx = lua_tointeger(L, 2) + 1;
jbe@134 594 lua_pushvalue(L, 1);
jbe@139 595 lua_rawget(L, json_ipairs_iterfunc_shadowtbl_idx);
jbe@134 596 if (lua_isnil(L, -1)) return luaL_error(L, "Shadow table not found");
jbe@134 597 lua_rawgeti(L, -1, idx);
jbe@134 598 if (lua_isnil(L, -1)) return 0;
jbe@134 599 lua_pushinteger(L, idx);
jbe@139 600 if (lua_rawequal(L, -2, json_ipairs_iterfunc_nullmark_idx)) lua_pushnil(L);
jbe@134 601 else lua_pushvalue(L, -2);
jbe@134 602 return 2;
jbe@134 603 }
jbe@134 604
jbe@134 605 static int json_ipairs(lua_State *L) {
jbe@139 606 lua_pushcfunction(L, json_ipairs_iterfunc);
jbe@134 607 lua_pushvalue(L, 1);
jbe@134 608 lua_pushinteger(L, 0);
jbe@134 609 return 3;
jbe@134 610 }
jbe@134 611
jbe@121 612 static const struct luaL_Reg json_module_functions[] = {
jbe@133 613 {"object", json_object},
jbe@133 614 {"array", json_array},
jbe@121 615 {"import", json_import},
jbe@130 616 {"get", json_get},
jbe@127 617 {"type", json_type},
jbe@123 618 {"isnull", json_isnull},
jbe@131 619 {"setnull", json_setnull},
jbe@121 620 {NULL, NULL}
jbe@121 621 };
jbe@121 622
jbe@126 623 static const struct luaL_Reg json_metatable_functions[] = {
jbe@130 624 {"__len", json_len},
jbe@130 625 {"__index", json_index},
jbe@130 626 {"__newindex", json_newindex},
jbe@135 627 {"__pairs", json_pairs},
jbe@134 628 {"__ipairs", json_ipairs},
jbe@126 629 {NULL, NULL}
jbe@126 630 };
jbe@126 631
jbe@121 632 int luaopen_json(lua_State *L) {
jbe@126 633 lua_settop(L, 0);
jbe@138 634 lua_newtable(L); // library
jbe@138 635 lua_newtable(L);
jbe@138 636 luaL_setfuncs(L, json_metatable_functions, 0);
jbe@138 637 json_regstore(L, json_unknownmt);
jbe@138 638 lua_setfield(L, 1, "ambiguous_mt");
jbe@138 639 lua_newtable(L);
jbe@138 640 luaL_setfuncs(L, json_metatable_functions, 0);
jbe@138 641 json_regstore(L, json_objectmt);
jbe@138 642 lua_setfield(L, 1, "object_mt");
jbe@138 643 lua_newtable(L);
jbe@138 644 luaL_setfuncs(L, json_metatable_functions, 0);
jbe@138 645 json_regstore(L, json_arraymt);
jbe@138 646 lua_setfield(L, 1, "array_mt");
jbe@138 647 lua_newtable(L); // ephemeron table to store shadow tables for each JSON object/array to allow NULL values returned as nil
jbe@138 648 lua_newtable(L); // metatable for ephemeron table
jbe@121 649 lua_pushliteral(L, "__mode");
jbe@121 650 lua_pushliteral(L, "k");
jbe@138 651 lua_rawset(L, -3);
jbe@138 652 lua_setmetatable(L, -2);
jbe@138 653 json_regstore(L, json_shadowtbl);
jbe@138 654 lua_newtable(L);
jbe@138 655 json_regstore(L, json_nullmark);
jbe@138 656 lua_settop(L, 1);
jbe@138 657 luaL_setfuncs(L, json_module_functions, 0);
jbe@121 658 return 1;
jbe@121 659 }

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