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view libraries/json/json.c @ 143:6f723e60acdc
Bugfixes in JSON library
| author | jbe |
|---|---|
| date | Wed Jul 30 02:36:37 2014 +0200 (2014-07-30) |
| parents | a686ed2ce967 |
| children | 0690fe79b673 |
line source
1 #include <lua.h>
2 #include <lauxlib.h>
3 #include <stdlib.h>
4 #include <string.h>
6 #define JSON_MAXDEPTH 100
8 #define JSON_REGENT static char
9 #define JSON_REGREF void *
11 JSON_REGENT json_nullmark;
12 JSON_REGENT json_shadowtbl;
13 JSON_REGENT json_unknownmt;
14 JSON_REGENT json_objectmt;
15 JSON_REGENT json_arraymt;
17 #define json_regfetch(L, x) (lua_pushlightuserdata((L), &(x)), lua_rawget((L), LUA_REGISTRYINDEX))
19 #define json_regstore(L, x) (lua_pushlightuserdata(L, &(x)), lua_pushvalue(L, -2), lua_rawset(L, LUA_REGISTRYINDEX));
21 // marks a table as JSON object or JSON array:
22 // (returns its modified argument or a new table if argument is nil)
23 static int json_mark(lua_State *L, JSON_REGREF mt) {
24 // if argument is nil, then create new table:
25 if (lua_isnoneornil(L, 1)) {
26 lua_settop(L, 0);
27 lua_newtable(L);
28 // set shadow table:
29 json_regfetch(L, json_shadowtbl);
30 lua_pushvalue(L, 1);
31 lua_newtable(L);
32 lua_rawset(L, -3);
33 } else {
34 // check if shadow table already exists:
35 json_regfetch(L, json_shadowtbl);
36 lua_pushvalue(L, 1);
37 lua_rawget(L, -2);
38 if (lua_isnil(L, -1)) {
39 // set shadow table and leave it on top of stack:
40 lua_newtable(L);
41 lua_pushvalue(L, 1);
42 lua_pushvalue(L, -2);
43 lua_rawset(L, -5);
44 }
45 for(lua_pushnil(L); lua_next(L, 1); lua_pop(L, 1)) {
46 lua_pushvalue(L, -2);
47 lua_pushnil(L);
48 lua_rawset(L, 1);
49 lua_pushvalue(L, -2);
50 lua_pushvalue(L, -2);
51 lua_rawset(L, -5);
52 }
53 }
54 // discard everything but table to return:
55 lua_settop(L, 1);
56 // set metatable:
57 json_regfetch(L, *mt);
58 lua_setmetatable(L, 1);
59 // return table:
60 return 1;
61 }
63 // marks a table as JSON object:
64 // (returns its modified argument or a new table if argument is nil)
65 static int json_object(lua_State *L) {
66 return json_mark(L, &json_objectmt);
67 }
69 // marks a table as JSON array:
70 // (returns its modified argument or a new table if argument is nil)
71 static int json_array(lua_State *L) {
72 return json_mark(L, &json_arraymt);
73 }
75 #define JSON_STATE_VALUE 0
76 #define JSON_STATE_OBJECT_KEY 1
77 #define JSON_STATE_OBJECT_KEY_TERMINATOR 2
78 #define JSON_STATE_OBJECT_VALUE 3
79 #define JSON_STATE_OBJECT_SEPARATOR 4
80 #define JSON_STATE_ARRAY_VALUE 5
81 #define JSON_STATE_ARRAY_SEPARATOR 6
82 #define JSON_STATE_END 7
84 #define json_import_objectmt_idx 2
85 #define json_import_arraymt_idx 3
86 #define json_import_shadowtbl_idx 4
87 #define json_import_nullmark_idx 5
89 // decodes a JSON document:
90 static int json_import(lua_State *L) {
91 const char *str; // string to parse
92 size_t total; // total length of string to parse
93 size_t pos = 0; // current position in string to parse
94 size_t level = 0; // nested levels of objects/arrays currently being processed
95 int mode = JSON_STATE_VALUE; // state of parser
96 char c; // variable to store a single character to be processed
97 luaL_Buffer luabuf; // Lua buffer to decode (possibly escaped) strings
98 char *cbuf; // C buffer to decode (possibly escaped) strings
99 size_t writepos; // write position of decoded strings in C buffer
100 // limit stack to 1 element:
101 lua_settop(L, 1);
102 // push json_objectmt on stack position 2:
103 json_regfetch(L, json_objectmt);
104 // push json_arraymt on stack position 3:
105 json_regfetch(L, json_arraymt);
106 // push json_shadowtbl on stack position 4:
107 json_regfetch(L, json_shadowtbl);
108 // push json_nullmark on stack position 5:
109 json_regfetch(L, json_nullmark);
110 // require string as first argument:
111 str = luaL_checklstring(L, 1, &total);
112 // if string contains a NULL byte, this is a syntax error
113 if (strlen(str) != total) goto json_import_syntax_error;
114 // main loop of parser:
115 json_import_loop:
116 // skip whitespace and store next character in variable 'c':
117 while (c = str[pos], c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == '\f') pos++;
118 // switch statement to handle certain (single) characters:
119 switch (c) {
120 // handle end of JSON document:
121 case 0:
122 // if end of JSON document was expected, then return top element of stack as result:
123 if (mode == JSON_STATE_END) return 1;
124 // otherwise, the JSON document was malformed:
125 json_import_unexpected_eof:
126 lua_pushnil(L);
127 if (level == 0) lua_pushliteral(L, "Empty string");
128 else lua_pushliteral(L, "Unexpected end of JSON document");
129 return 2;
130 // new JSON object:
131 case '{':
132 // if a JSON object is not expected here, then return an error:
133 if (mode != JSON_STATE_VALUE && mode != JSON_STATE_OBJECT_VALUE && mode != JSON_STATE_ARRAY_VALUE)
134 goto json_import_syntax_error;
135 // create JSON object on stack:
136 lua_newtable(L);
137 // set metatable of JSON object:
138 lua_pushvalue(L, json_import_objectmt_idx);
139 lua_setmetatable(L, -2);
140 // create internal shadow table on stack:
141 lua_newtable(L);
142 // register internal shadow table (and cleanup stack afterwards):
143 lua_pushvalue(L, -2);
144 lua_pushvalue(L, -2);
145 lua_rawset(L, json_import_shadowtbl_idx);
146 // expect object key (or end of object) and continue with loop:
147 mode = JSON_STATE_OBJECT_KEY;
148 goto json_import_open;
149 // new JSON array:
150 case '[':
151 // if a JSON array is not expected here, then return an error:
152 if (mode != JSON_STATE_VALUE && mode != JSON_STATE_OBJECT_VALUE && mode != JSON_STATE_ARRAY_VALUE)
153 goto json_import_syntax_error;
154 // create JSON array on stack:
155 lua_newtable(L);
156 // set metatable of JSON array:
157 lua_pushvalue(L, json_import_arraymt_idx);
158 lua_setmetatable(L, -2);
159 // create internal shadow table on stack:
160 lua_newtable(L);
161 // register internal shadow table (and cleanup stack afterwards):
162 lua_pushvalue(L, -2);
163 lua_pushvalue(L, -2);
164 lua_rawset(L, json_import_shadowtbl_idx);
165 // add nil as key (needed to keep stack balance) and as magic to detect arrays:
166 lua_pushnil(L);
167 // expect array value (or end of array) and continue with loop:
168 mode = JSON_STATE_ARRAY_VALUE;
169 // continue with common code for opening JSON object and JSON array:
170 // commn code for opening JSON object or JSON array:
171 json_import_open:
172 // limit nested levels:
173 if (level >= JSON_MAXDEPTH) {
174 lua_pushnil(L);
175 lua_pushliteral(L, "Too many nested JSON levels");
176 return 2;
177 }
178 // additional buffer overflow protection:
179 if (!lua_checkstack(L, LUA_MINSTACK))
180 return luaL_error(L, "Caught stack overflow in JSON import function (too many nested levels and stack size too small)");
181 // increment level:
182 level++;
183 // consume input character:
184 pos++;
185 goto json_import_loop;
186 // end of JSON object:
187 case '}':
188 // if end of JSON object is not expected here, then return an error:
189 if (mode != JSON_STATE_OBJECT_KEY && mode != JSON_STATE_OBJECT_SEPARATOR)
190 goto json_import_syntax_error;
191 // jump to common code for end of JSON object and JSON array:
192 goto json_import_close;
193 // end of JSON array:
194 case ']':
195 // if end of JSON array is not expected here, then return an error:
196 if (mode != JSON_STATE_ARRAY_VALUE && mode != JSON_STATE_ARRAY_SEPARATOR)
197 goto json_import_syntax_error;
198 // pop nil key/magic:
199 lua_pop(L, 1);
200 // continue with common code for end of JSON object and JSON array:
201 // common code for end of JSON object or JSON array:
202 json_import_close:
203 // consume input character:
204 pos++;
205 // pop shadow table:
206 lua_pop(L, 1);
207 // check if nested:
208 if (--level) {
209 // if nested, then check if outer(!) structure is an array or object:
210 if (lua_isnil(L, -2)) {
211 // select array value processing:
212 mode = JSON_STATE_ARRAY_VALUE;
213 } else {
214 // select object value processing:
215 mode = JSON_STATE_OBJECT_VALUE;
216 }
217 // store value in outer structure:
218 goto json_import_process_value;
219 }
220 // if not nested, then expect end of JSON document and continue with loop:
221 mode = JSON_STATE_END;
222 goto json_import_loop;
223 // key terminator:
224 case ':':
225 // if key terminator is not expected here, then return an error:
226 if (mode != JSON_STATE_OBJECT_KEY_TERMINATOR)
227 goto json_import_syntax_error;
228 // consume input character:
229 pos++;
230 // set state of parser and continue with loop:
231 mode = JSON_STATE_OBJECT_VALUE;
232 goto json_import_loop;
233 // value terminator (NOTE: trailing comma at end of value or key-value list is tolerated by this parser)
234 case ',':
235 // change parser state accordingly:
236 if (mode == JSON_STATE_OBJECT_SEPARATOR) {
237 mode = JSON_STATE_OBJECT_KEY;
238 } else if (mode == JSON_STATE_ARRAY_SEPARATOR) {
239 mode = JSON_STATE_ARRAY_VALUE;
240 } else {
241 // if value terminator is not expected here, then return an error:
242 goto json_import_syntax_error;
243 }
244 // consume input character:
245 pos++;
246 // continue with loop:
247 goto json_import_loop;
248 // string literal:
249 case '"':
250 // prepare buffer to decode string (with maximum possible length) and set write position to zero:
251 cbuf = luaL_buffinitsize(L, &luabuf, total-pos);
252 writepos = 0;
253 // consume quote character:
254 pos++;
255 // read next character until encountering end quote:
256 while ((c = str[pos++]) != '"') {
257 if (c == 0) {
258 // handle unexpected end-of-string:
259 goto json_import_unexpected_eof;
260 } else if (c < 32 || c == 127) {
261 // do not allow ASCII control characters:
262 // NOTE: illegal UTF-8 sequences and extended control characters are not sanitized
263 // by this parser to allow different encodings than Unicode
264 lua_pushnil(L);
265 lua_pushliteral(L, "Unexpected control character in JSON string");
266 return 2;
267 } else if (c == '\\') {
268 // read next char after backslash escape:
269 c = str[pos++];
270 switch (c) {
271 // unexpected end-of-string:
272 case 0:
273 goto json_import_unexpected_eof;
274 // unescaping of quotation mark, slash, and backslash:
275 case '"':
276 case '/':
277 case '\\':
278 cbuf[writepos++] = c;
279 break;
280 // unescaping of backspace:
281 case 'b':
282 cbuf[writepos++] = '\b';
283 break;
284 // unescaping of form-feed:
285 case 'f':
286 cbuf[writepos++] = '\f';
287 break;
288 // unescaping of new-line:
289 case 'n':
290 cbuf[writepos++] = '\n';
291 break;
292 // unescaping of carriage-return:
293 case 'r':
294 cbuf[writepos++] = '\r';
295 break;
296 // unescaping of tabulator:
297 case 't':
298 cbuf[writepos++] = '\t';
299 break;
300 // unescaping of UTF-16 characters
301 case 'u':
302 lua_pushnil(L);
303 lua_pushliteral(L, "JSON unicode escape sequences are not implemented yet"); // TODO
304 return 2;
305 // unexpected escape sequence:
306 default:
307 lua_pushnil(L);
308 lua_pushliteral(L, "Unexpected string escape sequence in JSON document");
309 return 2;
310 }
311 } else {
312 // normal character:
313 cbuf[writepos++] = c;
314 }
315 }
316 // process buffer to Lua string:
317 luaL_pushresultsize(&luabuf, writepos);
318 // continue with processing of decoded string:
319 goto json_import_process_value;
320 }
321 // process values whose type is is not deducible from a single character:
322 if ((c >= '0' && c <= '9') || c == '-' || c == '+') {
323 // numbers:
324 char *endptr;
325 double numval;
326 numval = strtod(str+pos, &endptr);
327 if (endptr == str+pos) goto json_import_syntax_error;
328 pos += endptr - (str+pos);
329 lua_pushnumber(L, numval);
330 } else if (!strncmp(str+pos, "true", 4)) {
331 // consume 4 input characters for "true":
332 pos += 4;
333 // put Lua true value on stack:
334 lua_pushboolean(L, 1);
335 } else if (!strncmp(str+pos, "false", 5)) {
336 // consume 5 input characters for "false":
337 pos += 5;
338 // put Lua false value on stack:
339 lua_pushboolean(L, 0);
340 } else if (!strncmp(str+pos, "null", 4)) {
341 // consume 4 input characters for "null":
342 pos += 4;
343 // put special null-marker on stack:
344 lua_pushvalue(L, json_import_nullmark_idx);
345 } else {
346 // all other cases are a syntax error:
347 goto json_import_syntax_error;
348 }
349 // process a decoded value or key value pair (expected on top of Lua stack):
350 json_import_process_value:
351 switch (mode) {
352 // an object key has been read:
353 case JSON_STATE_OBJECT_KEY:
354 // if an object key is not a string, then this is a syntax error:
355 if (lua_type(L, -1) != LUA_TSTRING) goto json_import_syntax_error;
356 // expect key terminator and continue with loop:
357 mode = JSON_STATE_OBJECT_KEY_TERMINATOR;
358 goto json_import_loop;
359 // a key value pair has been read:
360 case JSON_STATE_OBJECT_VALUE:
361 // store key value pair in outer shadow table:
362 lua_rawset(L, -3);
363 // expect value terminator (or end of object) and continue with loop:
364 mode = JSON_STATE_OBJECT_SEPARATOR;
365 goto json_import_loop;
366 // an array value has been read:
367 case JSON_STATE_ARRAY_VALUE:
368 // store value in outer shadow table:
369 lua_rawseti(L, -3, lua_rawlen(L, -3) + 1);
370 // expect value terminator (or end of object) and continue with loop:
371 mode = JSON_STATE_ARRAY_SEPARATOR;
372 goto json_import_loop;
373 // a single value has been read:
374 case JSON_STATE_VALUE:
375 // leave value on top of stack, expect end of JSON document, and continue with loop:
376 mode = JSON_STATE_END;
377 goto json_import_loop;
378 }
379 // syntax error handling (only reachable by goto statement):
380 json_import_syntax_error:
381 lua_pushnil(L);
382 lua_pushliteral(L, "Syntax error in JSON document");
383 return 2;
384 }
386 #define json_path_shadowtbl_idx 1
387 #define json_path_nullmark_idx 2
388 #define json_path_idxshift 2
390 // gets a value or its type from a JSON document (first argument)
391 // optionally using a path (variable number of keys after first argument):
392 static int json_path(lua_State *L, int type_mode) {
393 int stacktop;
394 int idx = 2 + json_path_idxshift;
395 // insert json_shadowtbl on stack at position 1:
396 json_regfetch(L, json_shadowtbl);
397 lua_insert(L, 1);
398 // insert json_nullmark on stack at position 2:
399 json_regfetch(L, json_nullmark);
400 lua_insert(L, 2);
401 // store number of arguments:
402 stacktop = lua_gettop(L);
403 // follow path, starting with first argument as "current value":
404 lua_pushvalue(L, 1 + json_path_idxshift);
405 // process each "path key":
406 while (idx <= stacktop) {
407 // if "current value" is nil, then the path cannot be walked and nil is returned:
408 if (lua_isnil(L, -1)) return 1;
409 // try to get shadow table of "current value":
410 lua_pushvalue(L, -1);
411 lua_rawget(L, json_path_shadowtbl_idx);
412 if (lua_isnil(L, -1)) {
413 // if no shadow table is found,
414 // drop nil from stack:
415 lua_pop(L, 1);
416 if (lua_type(L, -1) == LUA_TTABLE) {
417 // if "current value" is a table,
418 // get "next value" using the "path key":
419 lua_pushvalue(L, idx++);
420 lua_gettable(L, -2);
421 } else {
422 // if "current value" is not a table,
423 // then the path cannot be walked and nil is returned:
424 lua_pushnil(L);
425 return 1;
426 }
427 } else {
428 // if a shadow table is found,
429 // set "current value" to its shadow table:
430 lua_replace(L, -2);
431 // get "next value" using the "path key":
432 lua_pushvalue(L, idx++);
433 lua_rawget(L, -2);
434 }
435 // the "next value" replaces the "current value":
436 lua_replace(L, -2);
437 }
438 if (!type_mode) {
439 // if a value (and not its type) was requested,
440 // check if value is the null-marker, and store nil on top of Lua stack in that case:
441 if (lua_rawequal(L, -1, json_path_nullmark_idx)) lua_pushnil(L);
442 } else {
443 // if the type was requested,
444 // check if value is the null-marker:
445 if (lua_rawequal(L, -1, json_path_nullmark_idx)) {
446 // if yes, store string "null" on top of Lua stack:
447 lua_pushliteral(L, "null");
448 } else {
449 // otherwise,
450 // check if metatable indicates "object" or "array":
451 if (lua_getmetatable(L, -1)) {
452 json_regfetch(L, json_objectmt);
453 if (lua_rawequal(L, -2, -1)) {
454 // return string "object":
455 lua_pushliteral(L, "object");
456 return 1;
457 }
458 json_regfetch(L, json_arraymt);
459 if (lua_rawequal(L, -3, -1)) {
460 // return string "array":
461 lua_pushliteral(L, "array");
462 return 1;
463 }
464 lua_pop(L, 3);
465 }
466 // otherwise, get the Lua type:
467 lua_pushstring(L, lua_typename(L, lua_type(L, -1)));
468 }
469 }
470 // return the top most value on the Lua stack:
471 return 1;
472 }
474 // gets a value from a JSON document (first argument)
475 // optionally using a path (variable number of keys after first argument):
476 static int json_get(lua_State *L) {
477 return json_path(L, 0);
478 }
480 // gets a value's type from a JSON document (first argument)
481 // optionally using a path (variable number of keys after first argument):
482 static int json_type(lua_State *L) {
483 return json_path(L, 1);
484 }
486 // checks if a value in a JSON document (first argument) is null:
487 static int json_isnull(lua_State *L) {
488 const char *jsontype;
489 lua_pushcfunction(L, json_type);
490 lua_insert(L, 1);
491 lua_call(L, lua_gettop(L) - 1, 1);
492 jsontype = lua_tostring(L, -1);
493 if (jsontype && !strcmp(jsontype, "null")) lua_pushboolean(L, 1);
494 else lua_pushboolean(L, 0);
495 return 1;
496 }
498 #define json_setnull_unknownmt_idx 3
499 #define json_setnull_objectmt_idx 4
500 #define json_setnull_arraymt_idx 5
501 #define json_setnull_shadowtbl_idx 6
503 static int json_setnull(lua_State *L) {
504 // truncate stack to two elements:
505 lua_settop(L, 2);
506 // push json_unknownmt to stack position 3:
507 json_regfetch(L, json_unknownmt);
508 // push json_objectmt to stack position 4:
509 json_regfetch(L, json_objectmt);
510 // push json_arraymt to stack position 5:
511 json_regfetch(L, json_arraymt);
512 // push json_shadowtbl to stack position 6:
513 json_regfetch(L, json_shadowtbl);
514 //
515 lua_getmetatable(L, 1);
516 if (
517 !lua_rawequal(L, -1, json_setnull_unknownmt_idx) &&
518 !lua_rawequal(L, -1, json_setnull_objectmt_idx) &&
519 !lua_rawequal(L, -1, json_setnull_arraymt_idx)
520 ) {
521 lua_pushvalue(L, json_setnull_unknownmt_idx);
522 lua_setmetatable(L, 1);
523 }
524 lua_pushvalue(L, 1);
525 lua_rawget(L, json_setnull_shadowtbl_idx);
526 if (lua_isnil(L, -1)) {
527 lua_newtable(L);
528 lua_pushvalue(L, 1);
529 lua_pushvalue(L, -2);
530 lua_rawset(L, json_setnull_shadowtbl_idx);
531 }
532 lua_pushvalue(L, 2);
533 json_regfetch(L, json_nullmark);
534 lua_rawset(L, -3);
535 return 0;
536 }
538 static int json_len(lua_State *L) {
539 lua_settop(L, 1);
540 json_regfetch(L, json_shadowtbl);
541 lua_pushvalue(L, 1);
542 lua_rawget(L, -2);
543 lua_pushinteger(L, lua_rawlen(L, lua_isnil(L, -1) ? 1 : -1));
544 return 1;
545 }
547 #define json_index_nullmark_idx 3
548 #define json_index_shadowtbl_idx 4
550 static int json_index(lua_State *L) {
551 lua_settop(L, 2);
552 json_regfetch(L, json_nullmark); // on stack position 3
553 json_regfetch(L, json_shadowtbl);
554 lua_pushvalue(L, 1);
555 lua_rawget(L, json_index_shadowtbl_idx);
556 if (lua_isnil(L, -1)) return luaL_error(L, "Shadow table not found");
557 lua_pushvalue(L, 2);
558 lua_rawget(L, -2);
559 if (lua_rawequal(L, -1, json_index_nullmark_idx)) lua_pushnil(L);
560 return 1;
561 }
563 static int json_newindex(lua_State *L) {
564 lua_settop(L, 3);
565 json_regfetch(L, json_shadowtbl);
566 lua_pushvalue(L, 1);
567 lua_rawget(L, -2);
568 if (lua_isnil(L, -1)) return luaL_error(L, "Shadow table not found");
569 lua_replace(L, 1);
570 lua_settop(L, 3);
571 lua_rawset(L, 1);
572 return 1;
573 }
575 #define json_pairs_iterfunc_nullmark_idx 3
576 #define json_pairs_iterfunc_shadowtbl_idx 4
578 static int json_pairs_iterfunc(lua_State *L) {
579 lua_settop(L, 2);
580 json_regfetch(L, json_nullmark); // on stack position 3
581 json_regfetch(L, json_shadowtbl);
582 lua_pushvalue(L, 1);
583 lua_rawget(L, json_pairs_iterfunc_shadowtbl_idx);
584 if (lua_isnil(L, -1)) return luaL_error(L, "Shadow table not found");
585 lua_pushvalue(L, 2);
586 if (!lua_next(L, -2)) return 0;
587 if (lua_rawequal(L, -1, json_pairs_iterfunc_nullmark_idx)) {
588 lua_pop(L, 1);
589 lua_pushnil(L);
590 }
591 return 2;
592 }
594 static int json_pairs(lua_State *L) {
595 lua_pushcfunction(L, json_pairs_iterfunc);
596 lua_pushvalue(L, 1);
597 lua_pushnil(L);
598 return 3;
599 }
601 #define json_ipairs_iterfunc_nullmark_idx 3
602 #define json_ipairs_iterfunc_shadowtbl_idx 4
604 static int json_ipairs_iterfunc(lua_State *L) {
605 int idx;
606 lua_settop(L, 2);
607 json_regfetch(L, json_nullmark); // on stack position 3
608 json_regfetch(L, json_shadowtbl);
609 idx = lua_tointeger(L, 2) + 1;
610 lua_pushvalue(L, 1);
611 lua_rawget(L, json_ipairs_iterfunc_shadowtbl_idx);
612 if (lua_isnil(L, -1)) return luaL_error(L, "Shadow table not found");
613 lua_rawgeti(L, -1, idx);
614 if (lua_isnil(L, -1)) return 0;
615 lua_pushinteger(L, idx);
616 if (lua_rawequal(L, -2, json_ipairs_iterfunc_nullmark_idx)) lua_pushnil(L);
617 else lua_pushvalue(L, -2);
618 return 2;
619 }
621 static int json_ipairs(lua_State *L) {
622 lua_pushcfunction(L, json_ipairs_iterfunc);
623 lua_pushvalue(L, 1);
624 lua_pushinteger(L, 0);
625 return 3;
626 }
628 static const struct luaL_Reg json_module_functions[] = {
629 {"object", json_object},
630 {"array", json_array},
631 {"import", json_import},
632 {"get", json_get},
633 {"type", json_type},
634 {"isnull", json_isnull},
635 {"setnull", json_setnull},
636 {NULL, NULL}
637 };
639 static const struct luaL_Reg json_metatable_functions[] = {
640 {"__len", json_len},
641 {"__index", json_index},
642 {"__newindex", json_newindex},
643 {"__pairs", json_pairs},
644 {"__ipairs", json_ipairs},
645 {NULL, NULL}
646 };
648 int luaopen_json(lua_State *L) {
649 lua_settop(L, 0);
650 lua_newtable(L); // library
651 lua_newtable(L);
652 luaL_setfuncs(L, json_metatable_functions, 0);
653 json_regstore(L, json_unknownmt);
654 lua_setfield(L, 1, "ambiguous_mt");
655 lua_newtable(L);
656 luaL_setfuncs(L, json_metatable_functions, 0);
657 json_regstore(L, json_objectmt);
658 lua_setfield(L, 1, "object_mt");
659 lua_newtable(L);
660 luaL_setfuncs(L, json_metatable_functions, 0);
661 json_regstore(L, json_arraymt);
662 lua_setfield(L, 1, "array_mt");
663 lua_newtable(L); // ephemeron table to store shadow tables for each JSON object/array to allow NULL values returned as nil
664 lua_newtable(L); // metatable for ephemeron table
665 lua_pushliteral(L, "__mode");
666 lua_pushliteral(L, "k");
667 lua_rawset(L, -3);
668 lua_setmetatable(L, -2);
669 json_regstore(L, json_shadowtbl);
670 lua_newtable(L);
671 json_regstore(L, json_nullmark);
672 lua_settop(L, 1);
673 luaL_setfuncs(L, json_module_functions, 0);
674 return 1;
675 }