webmcp

annotate libraries/json/json.c @ 138:8a533f370038

find changesets by author, revision, files, or words in the commit message
First part of refactoring JSON library (use LUA_REGISTRYINDEX with lightuserdata keys instead of C closures)
author jbe
date Mon Jul 28 23:39:23 2014 +0200 (2014-07-28)
parents f490b78827d6
children a4ce17051eff
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@136 192 lua_pushvalue(L, c == '}' ? -4 : -3);
jbe@138 193 lua_getmetatable(L, -1);
jbe@138 194 if (lua_touserdata(L, -1) == &json_arraymt) {
jbe@136 195 // select array value processing:
jbe@124 196 mode = JSON_STATE_ARRAY_VALUE;
jbe@121 197 } else {
jbe@136 198 // select object value processing:
jbe@124 199 mode = JSON_STATE_OBJECT_VALUE;
jbe@121 200 }
jbe@138 201 // pop metatable from stack (that was needed for type distinction):
jbe@136 202 lua_pop(L, 1);
jbe@136 203 // store value in outer structure:
jbe@121 204 goto json_import_process_value;
jbe@121 205 }
jbe@136 206 // if not nested, then expect end of JSON document and continue with loop:
jbe@136 207 mode = JSON_STATE_END;
jbe@121 208 goto json_import_loop;
jbe@136 209 // key terminator:
jbe@121 210 case ':':
jbe@136 211 // if key terminator is not expected here, then return an error:
jbe@124 212 if (mode != JSON_STATE_OBJECT_KEY_TERMINATOR)
jbe@121 213 goto json_import_syntax_error;
jbe@136 214 // consume input character:
jbe@121 215 pos++;
jbe@136 216 // set state of parser and continue with loop:
jbe@124 217 mode = JSON_STATE_OBJECT_VALUE;
jbe@121 218 goto json_import_loop;
jbe@136 219 // value terminator (NOTE: trailing comma at end of value or key-value list is tolerated by this parser)
jbe@121 220 case ',':
jbe@136 221 // change parser state accordingly:
jbe@124 222 if (mode == JSON_STATE_OBJECT_SEPARATOR) {
jbe@124 223 mode = JSON_STATE_OBJECT_KEY;
jbe@124 224 } else if (mode == JSON_STATE_ARRAY_SEPARATOR) {
jbe@124 225 mode = JSON_STATE_ARRAY_VALUE;
jbe@121 226 } else {
jbe@136 227 // if value terminator is not expected here, then return an error:
jbe@136 228 goto json_import_syntax_error;
jbe@121 229 }
jbe@136 230 // consume input character:
jbe@121 231 pos++;
jbe@136 232 // continue with loop:
jbe@121 233 goto json_import_loop;
jbe@136 234 // string literal:
jbe@121 235 case '"':
jbe@136 236 // prepare buffer to decode string (with maximum possible length) and set write position to zero:
jbe@121 237 cbuf = luaL_buffinitsize(L, &luabuf, total-pos);
jbe@121 238 writepos = 0;
jbe@136 239 // consume quote character:
jbe@121 240 pos++;
jbe@136 241 // read next character until encountering end quote:
jbe@121 242 while ((c = str[pos++]) != '"') {
jbe@121 243 if (c == 0) {
jbe@136 244 // handle unexpected end-of-string:
jbe@121 245 goto json_import_unexpected_eof;
jbe@121 246 } else if (c < 32 || c == 127) {
jbe@136 247 // do not allow ASCII control characters:
jbe@136 248 // NOTE: illegal UTF-8 sequences and extended control characters are not sanitized
jbe@136 249 // by this parser to allow different encodings than Unicode
jbe@121 250 lua_pushnil(L);
jbe@121 251 lua_pushliteral(L, "Unexpected control character in JSON string");
jbe@121 252 return 2;
jbe@121 253 } else if (c == '\\') {
jbe@136 254 // read next char after backslash escape:
jbe@121 255 c = str[pos++];
jbe@121 256 switch (c) {
jbe@136 257 // unexpected end-of-string:
jbe@121 258 case 0:
jbe@121 259 goto json_import_unexpected_eof;
jbe@136 260 // unescaping of quotation mark, slash, and backslash:
jbe@121 261 case '"':
jbe@121 262 case '/':
jbe@121 263 case '\\':
jbe@121 264 cbuf[writepos++] = c;
jbe@121 265 break;
jbe@136 266 // unescaping of backspace:
jbe@121 267 case 'b':
jbe@121 268 cbuf[writepos++] = '\b';
jbe@121 269 break;
jbe@136 270 // unescaping of form-feed:
jbe@121 271 case 'f':
jbe@121 272 cbuf[writepos++] = '\f';
jbe@121 273 break;
jbe@136 274 // unescaping of new-line:
jbe@121 275 case 'n':
jbe@121 276 cbuf[writepos++] = '\n';
jbe@121 277 break;
jbe@136 278 // unescaping of carriage-return:
jbe@121 279 case 'r':
jbe@121 280 cbuf[writepos++] = '\r';
jbe@121 281 break;
jbe@136 282 // unescaping of tabulator:
jbe@121 283 case 't':
jbe@121 284 cbuf[writepos++] = '\t';
jbe@121 285 break;
jbe@136 286 // unescaping of UTF-16 characters
jbe@121 287 case 'u':
jbe@121 288 lua_pushnil(L);
jbe@121 289 lua_pushliteral(L, "JSON unicode escape sequences are not implemented yet"); // TODO
jbe@121 290 return 2;
jbe@136 291 // unexpected escape sequence:
jbe@121 292 default:
jbe@121 293 lua_pushnil(L);
jbe@121 294 lua_pushliteral(L, "Unexpected string escape sequence in JSON document");
jbe@121 295 return 2;
jbe@121 296 }
jbe@121 297 } else {
jbe@136 298 // normal character:
jbe@121 299 cbuf[writepos++] = c;
jbe@121 300 }
jbe@121 301 }
jbe@136 302 // process buffer to Lua string:
jbe@121 303 luaL_pushresultsize(&luabuf, writepos);
jbe@136 304 // continue with processing of decoded string:
jbe@121 305 goto json_import_process_value;
jbe@121 306 }
jbe@136 307 // process values whose type is is not deducible from a single character:
jbe@136 308 if ((c >= '0' && c <= '9') || c == '-' || c == '+') {
jbe@136 309 // numbers:
jbe@122 310 char *endptr;
jbe@122 311 double numval;
jbe@122 312 numval = strtod(str+pos, &endptr);
jbe@122 313 if (endptr == str+pos) goto json_import_syntax_error;
jbe@122 314 pos += endptr - (str+pos);
jbe@122 315 lua_pushnumber(L, numval);
jbe@122 316 } else if (!strncmp(str+pos, "true", 4)) {
jbe@136 317 // consume 4 input characters for "true":
jbe@121 318 pos += 4;
jbe@136 319 // put Lua true value on stack:
jbe@136 320 lua_pushboolean(L, 1);
jbe@121 321 } else if (!strncmp(str+pos, "false", 5)) {
jbe@136 322 // consume 5 input characters for "false":
jbe@121 323 pos += 5;
jbe@136 324 // put Lua false value on stack:
jbe@136 325 lua_pushboolean(L, 0);
jbe@121 326 } else if (!strncmp(str+pos, "null", 4)) {
jbe@136 327 // consume 4 input characters for "null":
jbe@136 328 pos += 4;
jbe@136 329 // put special null-marker on stack:
jbe@138 330 lua_pushvalue(L, json_import_nullmark_idx);
jbe@121 331 } else {
jbe@136 332 // all other cases are a syntax error:
jbe@121 333 goto json_import_syntax_error;
jbe@121 334 }
jbe@136 335 // process a decoded value or key value pair (expected on top of Lua stack):
jbe@136 336 json_import_process_value:
jbe@121 337 switch (mode) {
jbe@136 338 // an object key has been read:
jbe@124 339 case JSON_STATE_OBJECT_KEY:
jbe@136 340 // if an object key is not a string, then this is a syntax error:
jbe@121 341 if (lua_type(L, -1) != LUA_TSTRING) goto json_import_syntax_error;
jbe@136 342 // expect key terminator and continue with loop:
jbe@124 343 mode = JSON_STATE_OBJECT_KEY_TERMINATOR;
jbe@121 344 goto json_import_loop;
jbe@136 345 // a key value pair has been read:
jbe@124 346 case JSON_STATE_OBJECT_VALUE:
jbe@136 347 // store key value pair in outer shadow table:
jbe@130 348 lua_rawset(L, -3);
jbe@136 349 // expect value terminator (or end of object) and continue with loop:
jbe@124 350 mode = JSON_STATE_OBJECT_SEPARATOR;
jbe@121 351 goto json_import_loop;
jbe@136 352 // an array value has been read:
jbe@124 353 case JSON_STATE_ARRAY_VALUE:
jbe@136 354 // store value in outer shadow table:
jbe@136 355 lua_rawseti(L, -2, lua_rawlen(L, -2) + 1);
jbe@136 356 // expect value terminator (or end of object) and continue with loop:
jbe@124 357 mode = JSON_STATE_ARRAY_SEPARATOR;
jbe@121 358 goto json_import_loop;
jbe@136 359 // a single value has been read:
jbe@124 360 case JSON_STATE_VALUE:
jbe@136 361 // leave value on top of stack, expect end of JSON document, and continue with loop:
jbe@124 362 mode = JSON_STATE_END;
jbe@121 363 goto json_import_loop;
jbe@121 364 }
jbe@136 365 // syntax error handling (only reachable by goto statement):
jbe@136 366 json_import_syntax_error:
jbe@121 367 lua_pushnil(L);
jbe@121 368 lua_pushliteral(L, "Syntax error in JSON document");
jbe@121 369 return 2;
jbe@121 370 }
jbe@121 371
jbe@138 372 #define json_path_shadowtbl_idx 1
jbe@138 373 #define json_path_nullmark_idx 2
jbe@138 374 #define json_path_idxshift 2
jbe@138 375
jbe@137 376 // gets a value or its type from a JSON document (first argument)
jbe@137 377 // optionally using a path (variable number of keys after first argument):
jbe@137 378 static int json_path(lua_State *L, int type_mode) {
jbe@138 379 int stacktop;
jbe@138 380 int idx = 2 + json_path_idxshift;
jbe@138 381 // insert json_shadowtbl on stack at position 1:
jbe@138 382 json_regfetch(L, json_shadowtbl);
jbe@138 383 lua_insert(L, 1);
jbe@138 384 // insert json_nullmark on stack at position 2:
jbe@138 385 json_regfetch(L, json_nullmark);
jbe@138 386 lua_insert(L, 2);
jbe@137 387 // store number of arguments:
jbe@138 388 stacktop = lua_gettop(L);
jbe@137 389 // follow path, starting with first argument as "current value":
jbe@138 390 lua_pushvalue(L, 1 + json_path_idxshift);
jbe@137 391 // process each "path key":
jbe@138 392 while (idx <= stacktop) {
jbe@137 393 // if "current value" is nil, then the path cannot be walked and nil is returned:
jbe@137 394 if (lua_isnil(L, -1)) return 1;
jbe@137 395 // try to get shadow table of "current value":
jbe@130 396 lua_pushvalue(L, -1);
jbe@138 397 lua_rawget(L, json_path_shadowtbl_idx);
jbe@126 398 if (lua_isnil(L, -1)) {
jbe@137 399 // if no shadow table is found,
jbe@137 400 // drop nil from stack:
jbe@126 401 lua_pop(L, 1);
jbe@130 402 if (lua_type(L, -1) == LUA_TTABLE) {
jbe@137 403 // if "current value" is a table,
jbe@137 404 // get "next value" using the "path key":
jbe@130 405 lua_pushvalue(L, idx++);
jbe@130 406 lua_gettable(L, -2);
jbe@130 407 } else {
jbe@137 408 // if "current value" is not a table,
jbe@137 409 // then the path cannot be walked and nil is returned:
jbe@130 410 lua_pushnil(L);
jbe@137 411 return 1;
jbe@130 412 }
jbe@130 413 } else {
jbe@137 414 // if a shadow table is found,
jbe@137 415 // set "current value" to its shadow table:
jbe@130 416 lua_replace(L, -2);
jbe@137 417 // get "next value" using the "path key":
jbe@130 418 lua_pushvalue(L, idx++);
jbe@130 419 lua_rawget(L, -2);
jbe@126 420 }
jbe@137 421 // the "next value" replaces the "current value":
jbe@130 422 lua_replace(L, -2);
jbe@126 423 }
jbe@137 424 if (!type_mode) {
jbe@137 425 // if a value (and not its type) was requested,
jbe@137 426 // check if value is the null-marker, and store nil on top of Lua stack in that case:
jbe@138 427 if (lua_rawequal(L, -1, json_path_nullmark_idx)) lua_pushnil(L);
jbe@137 428 } else {
jbe@137 429 // if the type was requested,
jbe@137 430 // check if value is the null-marker:
jbe@138 431 if (lua_rawequal(L, -1, json_path_nullmark_idx)) {
jbe@137 432 // if yes, store string "null" on top of Lua stack:
jbe@130 433 lua_pushliteral(L, "null");
jbe@137 434 } else {
jbe@137 435 // otherwise,
jbe@138 436 // check if metatable indicates "object" or "array":
jbe@138 437 if (lua_getmetatable(L, -1)) {
jbe@138 438 json_regfetch(L, json_objectmt);
jbe@138 439 if (lua_rawequal(L, -2, -1)) {
jbe@138 440 // return string "object":
jbe@138 441 lua_pushliteral(L, "object");
jbe@138 442 return 1;
jbe@138 443 }
jbe@138 444 json_regfetch(L, json_arraymt);
jbe@138 445 if (lua_rawequal(L, -3, -1)) {
jbe@138 446 // return string "array":
jbe@138 447 lua_pushliteral(L, "array");
jbe@138 448 return 1;
jbe@138 449 }
jbe@138 450 lua_pop(L, 3);
jbe@138 451 }
jbe@138 452 // otherwise, get the Lua type:
jbe@138 453 lua_pushstring(L, lua_typename(L, lua_type(L, -1)));
jbe@126 454 }
jbe@126 455 }
jbe@137 456 // return the top most value on the Lua stack:
jbe@137 457 return 1;
jbe@130 458 }
jbe@130 459
jbe@137 460 // gets a value from a JSON document (first argument)
jbe@137 461 // optionally using a path (variable number of keys after first argument):
jbe@130 462 static int json_get(lua_State *L) {
jbe@137 463 return json_path(L, 0);
jbe@130 464 }
jbe@130 465
jbe@137 466 // gets a value's type from a JSON document (first argument)
jbe@137 467 // optionally using a path (variable number of keys after first argument):
jbe@130 468 static int json_type(lua_State *L) {
jbe@137 469 return json_path(L, 1);
jbe@130 470 }
jbe@130 471
jbe@137 472 // checks if a value in a JSON document (first argument) is null:
jbe@130 473 static int json_isnull(lua_State *L) {
jbe@137 474 const char *jsontype;
jbe@138 475 lua_pushcfunction(L, json_type);
jbe@137 476 lua_insert(L, 1);
jbe@137 477 lua_call(L, lua_gettop(L) - 1, 1);
jbe@137 478 jsontype = lua_tostring(L, -1);
jbe@137 479 if (jsontype && !strcmp(jsontype, "null")) lua_pushboolean(L, 1);
jbe@137 480 else lua_pushboolean(L, 0);
jbe@137 481 return 1;
jbe@130 482 }
jbe@130 483
jbe@138 484 #define json_setnull_unknownmt_idx 3
jbe@138 485 #define json_setnull_objectmt_idx 4
jbe@138 486 #define json_setnull_arraymt_idx 5
jbe@138 487 #define json_setnull_shadowtbl_idx 6
jbe@138 488
jbe@131 489 static int json_setnull(lua_State *L) {
jbe@138 490 // truncate stack to two elements:
jbe@131 491 lua_settop(L, 2);
jbe@138 492 // push json_unknownmt to stack position 3:
jbe@138 493 json_regfetch(L, json_unknownmt);
jbe@138 494 // push json_objectmt to stack position 4:
jbe@138 495 json_regfetch(L, json_objectmt);
jbe@138 496 // push json_arraymt to stack position 5:
jbe@138 497 json_regfetch(L, json_arraymt);
jbe@138 498 // push json_shadowtbl to stack position 6:
jbe@138 499 json_regfetch(L, json_shadowtbl);
jbe@138 500 //
jbe@138 501 lua_getmetatable(L, 1);
jbe@138 502 if (
jbe@138 503 !lua_rawequal(L, -1, json_setnull_unknownmt_idx) &&
jbe@138 504 !lua_rawequal(L, -1, json_setnull_objectmt_idx) &&
jbe@138 505 !lua_rawequal(L, -1, json_setnull_arraymt_idx)
jbe@138 506 ) {
jbe@138 507 lua_pushvalue(L, json_setnull_unknownmt_idx);
jbe@138 508 lua_setmetatable(L, 1);
jbe@138 509 }
jbe@131 510 lua_pushvalue(L, 1);
jbe@138 511 lua_rawget(L, json_setnull_shadowtbl_idx);
jbe@131 512 if (lua_isnil(L, -1)) {
jbe@131 513 lua_newtable(L);
jbe@131 514 lua_pushvalue(L, 1);
jbe@131 515 lua_pushvalue(L, -2);
jbe@138 516 lua_rawset(L, json_setnull_shadowtbl_idx);
jbe@131 517 }
jbe@131 518 lua_pushvalue(L, 2);
jbe@138 519 json_regfetch(L, json_nullmark);
jbe@131 520 lua_rawset(L, -3);
jbe@131 521 return 0;
jbe@131 522 }
jbe@131 523
jbe@130 524 static int json_len(lua_State *L) {
jbe@130 525 lua_settop(L, 1);
jbe@138 526 json_regfetch(L, json_shadowtbl);
jbe@130 527 lua_pushvalue(L, 1);
jbe@138 528 lua_rawget(L, -2);
jbe@138 529 lua_pushinteger(L, lua_rawlen(L, lua_isnil(L, -1) ? 1 : -1));
jbe@123 530 return 1;
jbe@123 531 }
jbe@123 532
jbe@138 533 /*
jbe@138 534
jbe@130 535 static int json_index(lua_State *L) {
jbe@130 536 lua_settop(L, 2);
jbe@130 537 lua_pushvalue(L, 1);
jbe@130 538 lua_rawget(L, JSON_UPVAL_SHADOWTBL);
jbe@130 539 if (lua_isnil(L, -1)) return 1;
jbe@130 540 lua_pushvalue(L, 2);
jbe@130 541 lua_rawget(L, -2);
jbe@130 542 if (lua_rawequal(L, -1, JSON_UPVAL_NULLMARK)) lua_pushnil(L);
jbe@127 543 return 1;
jbe@127 544 }
jbe@127 545
jbe@130 546 static int json_newindex(lua_State *L) {
jbe@130 547 lua_settop(L, 3);
jbe@123 548 lua_pushvalue(L, 1);
jbe@130 549 lua_rawget(L, JSON_UPVAL_SHADOWTBL);
jbe@130 550 if (lua_isnil(L, -1)) return luaL_error(L, "Shadow table not found");
jbe@130 551 lua_replace(L, 1);
jbe@130 552 lua_rawset(L, 1);
jbe@121 553 return 1;
jbe@121 554 }
jbe@121 555
jbe@135 556 static int json_pairs_iterfunc(lua_State *L) {
jbe@135 557 lua_settop(L, 2);
jbe@135 558 lua_pushvalue(L, 1);
jbe@135 559 lua_rawget(L, JSON_UPVAL_SHADOWTBL);
jbe@135 560 if (lua_isnil(L, -1)) return luaL_error(L, "Shadow table not found");
jbe@135 561 lua_pushvalue(L, 2);
jbe@135 562 if (!lua_next(L, -2)) return 0;
jbe@135 563 if (lua_rawequal(L, -1, JSON_UPVAL_NULLMARK)) {
jbe@135 564 lua_pop(L, 1);
jbe@135 565 lua_pushnil(L);
jbe@135 566 }
jbe@135 567 return 2;
jbe@135 568 }
jbe@135 569
jbe@135 570 static int json_pairs(lua_State *L) {
jbe@135 571 lua_pushvalue(L, JSON_UPVAL_PAIRS_ITERFUNC);
jbe@135 572 lua_pushvalue(L, 1);
jbe@135 573 lua_pushnil(L);
jbe@135 574 return 3;
jbe@135 575 }
jbe@135 576
jbe@134 577 static int json_ipairs_iterfunc(lua_State *L) {
jbe@134 578 int idx;
jbe@134 579 lua_settop(L, 2);
jbe@134 580 idx = lua_tointeger(L, 2) + 1;
jbe@134 581 lua_pushvalue(L, 1);
jbe@134 582 lua_rawget(L, JSON_UPVAL_SHADOWTBL);
jbe@134 583 if (lua_isnil(L, -1)) return luaL_error(L, "Shadow table not found");
jbe@134 584 lua_rawgeti(L, -1, idx);
jbe@134 585 if (lua_isnil(L, -1)) return 0;
jbe@134 586 lua_pushinteger(L, idx);
jbe@134 587 if (lua_rawequal(L, -2, JSON_UPVAL_NULLMARK)) lua_pushnil(L);
jbe@134 588 else lua_pushvalue(L, -2);
jbe@134 589 return 2;
jbe@134 590 }
jbe@134 591
jbe@134 592 static int json_ipairs(lua_State *L) {
jbe@134 593 lua_pushvalue(L, JSON_UPVAL_IPAIRS_ITERFUNC);
jbe@134 594 lua_pushvalue(L, 1);
jbe@134 595 lua_pushinteger(L, 0);
jbe@134 596 return 3;
jbe@134 597 }
jbe@134 598
jbe@138 599 */
jbe@138 600
jbe@121 601 static const struct luaL_Reg json_module_functions[] = {
jbe@133 602 {"object", json_object},
jbe@133 603 {"array", json_array},
jbe@121 604 {"import", json_import},
jbe@130 605 {"get", json_get},
jbe@127 606 {"type", json_type},
jbe@123 607 {"isnull", json_isnull},
jbe@131 608 {"setnull", json_setnull},
jbe@121 609 {NULL, NULL}
jbe@121 610 };
jbe@121 611
jbe@126 612 static const struct luaL_Reg json_metatable_functions[] = {
jbe@130 613 {"__len", json_len},
jbe@138 614 /*
jbe@130 615 {"__index", json_index},
jbe@130 616 {"__newindex", json_newindex},
jbe@135 617 {"__pairs", json_pairs},
jbe@134 618 {"__ipairs", json_ipairs},
jbe@138 619 */
jbe@126 620 {NULL, NULL}
jbe@126 621 };
jbe@126 622
jbe@121 623 int luaopen_json(lua_State *L) {
jbe@126 624 lua_settop(L, 0);
jbe@138 625 lua_newtable(L); // library
jbe@138 626 lua_newtable(L);
jbe@138 627 luaL_setfuncs(L, json_metatable_functions, 0);
jbe@138 628 json_regstore(L, json_unknownmt);
jbe@138 629 lua_setfield(L, 1, "ambiguous_mt");
jbe@138 630 lua_newtable(L);
jbe@138 631 luaL_setfuncs(L, json_metatable_functions, 0);
jbe@138 632 json_regstore(L, json_objectmt);
jbe@138 633 lua_setfield(L, 1, "object_mt");
jbe@138 634 lua_newtable(L);
jbe@138 635 luaL_setfuncs(L, json_metatable_functions, 0);
jbe@138 636 json_regstore(L, json_arraymt);
jbe@138 637 lua_setfield(L, 1, "array_mt");
jbe@138 638 lua_newtable(L); // ephemeron table to store shadow tables for each JSON object/array to allow NULL values returned as nil
jbe@138 639 lua_newtable(L); // metatable for ephemeron table
jbe@121 640 lua_pushliteral(L, "__mode");
jbe@121 641 lua_pushliteral(L, "k");
jbe@138 642 lua_rawset(L, -3);
jbe@138 643 lua_setmetatable(L, -2);
jbe@138 644 json_regstore(L, json_shadowtbl);
jbe@138 645 lua_newtable(L);
jbe@138 646 json_regstore(L, json_nullmark);
jbe@138 647 lua_settop(L, 1);
jbe@138 648 luaL_setfuncs(L, json_module_functions, 0);
jbe@121 649 return 1;
jbe@121 650 }

Impressum / About Us