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annotate libraries/json/json.c @ 333:51b17cee8432

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Updated error message for accidentally setting globals
author jbe
date Tue Mar 24 17:27:28 2015 +0100 (2015-03-24)
parents eceb6f56e9ed
children f0303fca9218
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@154 5 #include <math.h>
jbe@121 6
jbe@144 7 // maximum number of nested JSON values (objects and arrays):
jbe@182 8 // NOTE: json_import can store 2^32 / 3 levels on stack swap (using
jbe@183 9 // also negative indicies after integer wraparound), and
jbe@183 10 // json_export can store even more levels, so 1024^3 =
jbe@183 11 // 1073741824 is a safe value and allows practically unlimited
jbe@183 12 // levels for JSON documents <= 2 GiB.
jbe@182 13 #define JSON_MAXDEPTH (1024*1024*1024)
jbe@142 14
jbe@193 15 // define type JSON_LIGHTUSERDATA and
jbe@193 16 // generate dummy memory addresses for lightuserdata values:
jbe@193 17 #define JSON_LIGHTUSERDATA char
jbe@193 18 static struct {
jbe@193 19 JSON_LIGHTUSERDATA nullmark; // lightuserdata value represents a NULL value
jbe@193 20 JSON_LIGHTUSERDATA shadowtbl; // lightuserdata key for shadow table
jbe@193 21 } json_lightuserdata;
jbe@193 22
jbe@193 23 // macros for special nullmark value:
jbe@193 24 #define json_isnullmark(L, i) (lua_touserdata((L), (i)) == &json_lightuserdata.nullmark)
jbe@193 25 #define json_pushnullmark(L) lua_pushlightuserdata((L), &json_lightuserdata.nullmark)
jbe@193 26
jbe@193 27 // macros for getting and setting shadow tables
jbe@193 28 #define json_setshadow(L, i) lua_rawsetp((L), (i), &json_lightuserdata.shadowtbl)
jbe@193 29 #define json_getshadow(L, i) lua_rawgetp((L), (i), &json_lightuserdata.shadowtbl)
jbe@193 30 #define json_createproxy(L) lua_createtable((L), 0, 1)
jbe@193 31
jbe@193 32 // generate additional dummy memory addresses that represent Lua objects
jbe@193 33 // via lightuserdata keys and LUA_REGISTRYINDEX:
jbe@193 34 static struct {
jbe@193 35 JSON_LIGHTUSERDATA objectmt; // metatable for JSON objects
jbe@193 36 JSON_LIGHTUSERDATA arraymt; // metatable for JSON arrays
jbe@193 37 } json_registry;
jbe@155 38
jbe@144 39 // macros for usage of Lua registry:
jbe@145 40 #define json_regpointer(x) (&json_registry.x)
jbe@151 41 #define json_regfetchpointer(L, x) lua_rawgetp((L), LUA_REGISTRYINDEX, (x))
jbe@151 42 #define json_regfetch(L, x) json_regfetchpointer(L, json_regpointer(x))
jbe@151 43 #define json_regstore(L, x) lua_rawsetp(L, LUA_REGISTRYINDEX, json_regpointer(x))
jbe@145 44
jbe@157 45 // returns the string "<JSON null marker>":
jbe@157 46 static int json_nullmark_tostring(lua_State *L) {
jbe@157 47 lua_pushliteral(L, "<JSON null marker>");
jbe@157 48 return 1;
jbe@157 49 }
jbe@157 50
jbe@202 51 #define json_object_source_idx 1
jbe@202 52 #define json_object_iterator_idx 2
jbe@202 53 #define json_object_output_idx 3
jbe@202 54 #define json_object_shadow_idx 4
jbe@202 55 #define json_object_iterfun_idx 5
jbe@202 56 #define json_object_itertbl_idx 6
jbe@169 57
jbe@202 58 // converts a Lua table (or any other iterable value) to a JSON object:
jbe@169 59 // (does never modify the argument, returns an empty object or array if argument is nil)
jbe@202 60 static int json_object(lua_State *L) {
jbe@171 61 // determine is argument is given:
jbe@202 62 if (lua_isnoneornil(L, json_object_source_idx)) {
jbe@171 63 // if no argument is given (or if argument is nil),
jbe@193 64 // create proxy table with shadow table, and leave proxy table on top of stack:
jbe@193 65 json_createproxy(L);
jbe@169 66 lua_newtable(L);
jbe@193 67 json_setshadow(L, -2);
jbe@169 68 } else {
jbe@171 69 // if an argument was given,
jbe@193 70 // stack shall contain only one function argument:
jbe@171 71 lua_settop(L, 1);
jbe@193 72 // check if there is an iterator function in its metatable:
jbe@202 73 if (luaL_getmetafield(L, json_object_source_idx, "__pairs")) {
jbe@193 74 // if there is an iterator function,
jbe@193 75 // leave it on stack position 2 and verify its type:
jbe@202 76 if (lua_type(L, json_object_iterator_idx) != LUA_TFUNCTION)
jbe@202 77 return luaL_error(L, "__pairs metamethod is not a function");
jbe@169 78 } else {
jbe@193 79 // if there is no iterator function,
jbe@193 80 // verify the type of the argument itself:
jbe@202 81 luaL_checktype(L, json_object_source_idx, LUA_TTABLE);
jbe@193 82 // push nil onto stack position 2:
jbe@169 83 lua_pushnil(L);
jbe@143 84 }
jbe@171 85 // create result table on stack position 3:
jbe@193 86 json_createproxy(L);
jbe@169 87 // create shadow table on stack position 4:
jbe@169 88 lua_newtable(L);
jbe@193 89 lua_pushvalue(L, -1);
jbe@193 90 json_setshadow(L, -3);
jbe@171 91 // check if iterator function exists:
jbe@202 92 if (lua_isnil(L, json_object_iterator_idx)) {
jbe@171 93 // if there is no iterator function,
jbe@202 94 // copy all string key value pairs to shadow table:
jbe@202 95 for (lua_pushnil(L); lua_next(L, json_object_source_idx); lua_pop(L, 1)) {
jbe@202 96 if (lua_type(L, -2) == LUA_TSTRING) {
jbe@202 97 lua_pushvalue(L, -2);
jbe@202 98 lua_pushvalue(L, -2);
jbe@202 99 lua_rawset(L, json_object_shadow_idx);
jbe@171 100 }
jbe@169 101 }
jbe@169 102 } else {
jbe@172 103 // if there is an iterator function,
jbe@172 104 // call iterator function with source value (first argument)
jbe@172 105 // and store 3 result values on stack positions 5 through 7:
jbe@202 106 lua_pushvalue(L, json_object_iterator_idx);
jbe@172 107 lua_pushvalue(L, 1);
jbe@172 108 lua_call(L, 1, 3);
jbe@175 109 // iterate through key value pairs and store some of them in shadow table
jbe@174 110 // while replacing nil values with null-marker:
jbe@172 111 while (1) {
jbe@175 112 // call iterfun function:
jbe@202 113 lua_pushvalue(L, json_object_iterfun_idx);
jbe@202 114 lua_pushvalue(L, json_object_itertbl_idx);
jbe@172 115 lua_pushvalue(L, -3);
jbe@172 116 lua_remove(L, -4);
jbe@172 117 lua_call(L, 2, 2);
jbe@175 118 // break iteration loop if key is nil:
jbe@172 119 if (lua_isnil(L, -2)) break;
jbe@175 120 // store key value pair only if key type is correct:
jbe@202 121 if (lua_type(L, -2) == LUA_TSTRING) {
jbe@175 122 // if key type is correct,
jbe@175 123 // push key onto stack:
jbe@172 124 lua_pushvalue(L, -2);
jbe@175 125 // if value is nil, push null-marker onto stack (as value):
jbe@174 126 if (lua_isnil(L, -2)) json_pushnullmark(L);
jbe@175 127 // else push value onto stack:
jbe@174 128 else lua_pushvalue(L, -2);
jbe@175 129 // set key value pair in shadow table:
jbe@202 130 lua_rawset(L, json_object_shadow_idx);
jbe@172 131 }
jbe@175 132 // pop value from stack, but leave key on stack:
jbe@172 133 lua_pop(L, 1);
jbe@172 134 }
jbe@143 135 }
jbe@171 136 // let result table be on top of stack:
jbe@202 137 lua_settop(L, json_object_output_idx);
jbe@136 138 }
jbe@171 139 // set metatable (for result table on top of stack):
jbe@202 140 json_regfetch(L, objectmt);
jbe@169 141 lua_setmetatable(L, -2);
jbe@171 142 // return table on top of stack:
jbe@136 143 return 1;
jbe@136 144 }
jbe@136 145
jbe@202 146 #define json_array_source_idx 1
jbe@202 147 #define json_array_output_idx 2
jbe@202 148 #define json_array_shadow_idx 3
jbe@136 149
jbe@175 150 // converts a Lua table (or any other iterable value) to a JSON array:
jbe@175 151 // (does never modify the argument, returns an empty object or array if argument is nil)
jbe@136 152 static int json_array(lua_State *L) {
jbe@202 153 // determine is argument is given:
jbe@202 154 if (lua_isnoneornil(L, json_array_source_idx)) {
jbe@202 155 // if no argument is given (or if argument is nil),
jbe@202 156 // create proxy table with shadow table, and leave proxy table on top of stack:
jbe@202 157 json_createproxy(L);
jbe@202 158 lua_newtable(L);
jbe@202 159 json_setshadow(L, -2);
jbe@202 160 } else {
jbe@202 161 lua_Integer arrayidx, arraylen;
jbe@202 162 // if an argument was given,
jbe@202 163 // stack shall contain only one function argument:
jbe@202 164 lua_settop(L, 1);
jbe@202 165 // create result table on stack position 2:
jbe@202 166 json_createproxy(L);
jbe@202 167 // create shadow table on stack position 3:
jbe@202 168 lua_newtable(L);
jbe@202 169 lua_pushvalue(L, -1);
jbe@202 170 json_setshadow(L, -3);
jbe@202 171 // determine length of array:
jbe@202 172 arraylen = luaL_len(L, json_array_source_idx);
jbe@202 173 // for an array, copy consecutive integer value pairs to shadow table:
jbe@202 174 for (arrayidx=0; arrayidx<arraylen; ) {
jbe@202 175 // increment arrayidx at head of loop:
jbe@202 176 arrayidx++;
jbe@202 177 // get next array entry:
jbe@202 178 lua_pushinteger(L, arrayidx);
jbe@202 179 lua_gettable(L, json_array_source_idx);
jbe@202 180 // check if value is nil:
jbe@202 181 if (lua_isnil(L, -1)) {
jbe@202 182 // if yes, replace it with null-marker:
jbe@202 183 lua_pop(L, 1);
jbe@202 184 json_pushnullmark(L);
jbe@202 185 }
jbe@202 186 // store value in shadow table:
jbe@202 187 lua_rawseti(L, json_array_shadow_idx, arrayidx);
jbe@202 188 }
jbe@202 189 // let result table be on top of stack:
jbe@202 190 lua_settop(L, json_array_output_idx);
jbe@202 191 }
jbe@202 192 // set metatable (for result table on top of stack):
jbe@202 193 json_regfetch(L, arraymt);
jbe@202 194 lua_setmetatable(L, -2);
jbe@202 195 // return table on top of stack:
jbe@202 196 return 1;
jbe@136 197 }
jbe@136 198
jbe@145 199 // internal states of JSON parser:
jbe@124 200 #define JSON_STATE_VALUE 0
jbe@124 201 #define JSON_STATE_OBJECT_KEY 1
jbe@124 202 #define JSON_STATE_OBJECT_KEY_TERMINATOR 2
jbe@124 203 #define JSON_STATE_OBJECT_VALUE 3
jbe@124 204 #define JSON_STATE_OBJECT_SEPARATOR 4
jbe@124 205 #define JSON_STATE_ARRAY_VALUE 5
jbe@124 206 #define JSON_STATE_ARRAY_SEPARATOR 6
jbe@124 207 #define JSON_STATE_END 7
jbe@121 208
jbe@145 209 // special Lua stack indicies for json_import function:
jbe@138 210 #define json_import_objectmt_idx 2
jbe@138 211 #define json_import_arraymt_idx 3
jbe@193 212 #define json_import_stackswap_idx 4
jbe@138 213
jbe@168 214 // macros for hex decoding:
jbe@168 215 #define json_utf16_surrogate(x) ((x) >= 0xD800 && (x) <= 0xDFFF)
jbe@168 216 #define json_utf16_lead(x) ((x) >= 0xD800 && (x) <= 0xDBFF)
jbe@168 217 #define json_utf16_tail(x) ((x) >= 0xDC00 && (x) <= 0xDFFF)
jbe@167 218 #define json_import_readhex(x) \
jbe@167 219 do { \
jbe@167 220 x = 0; \
jbe@167 221 for (i=0; i<4; i++) { \
jbe@167 222 x <<= 4; \
jbe@167 223 c = str[pos++]; \
jbe@167 224 if (c >= '0' && c <= '9') x += c - '0'; \
jbe@167 225 else if (c >= 'A' && c <= 'F') x += c - 'A' + 10; \
jbe@167 226 else if (c >= 'a' && c <= 'f') x += c - 'a' + 10; \
jbe@167 227 else if (c == 0) goto json_import_unexpected_eof; \
jbe@167 228 else goto json_import_unexpected_escape; \
jbe@167 229 } \
jbe@167 230 } while (0)
jbe@167 231
jbe@136 232 // decodes a JSON document:
jbe@121 233 static int json_import(lua_State *L) {
jbe@181 234 int stackswapidx = 0; // elements in stack swap table
jbe@181 235 int i; // loop variable
jbe@181 236 const char *str; // string to parse
jbe@181 237 size_t total; // total length of string to parse
jbe@181 238 size_t pos = 0; // current position in string to parse
jbe@181 239 size_t level = 0; // nested levels of objects/arrays currently being processed
jbe@145 240 int mode = JSON_STATE_VALUE; // state of parser (i.e. "what's expected next?")
jbe@181 241 unsigned char c; // variable to store a single character to be processed (unsigned!)
jbe@181 242 luaL_Buffer luabuf; // Lua buffer to decode JSON string values
jbe@181 243 char *cbuf; // C buffer to decode JSON string values
jbe@181 244 size_t outlen; // maximum length or write position of C buffer
jbe@181 245 long codepoint; // decoded UTF-16 character or higher codepoint
jbe@181 246 long utf16tail; // second decoded UTF-16 character (surrogate tail)
jbe@181 247 size_t arraylen; // variable to temporarily store the array length
jbe@166 248 // require string as argument and convert to C string with length information:
jbe@166 249 str = luaL_checklstring(L, 1, &total);
jbe@166 250 // if string contains a NULL byte, this is a syntax error
jbe@166 251 if (strlen(str) != total) goto json_import_syntax_error;
jbe@147 252 // stack shall contain one function argument:
jbe@138 253 lua_settop(L, 1);
jbe@147 254 // push objectmt onto stack position 2:
jbe@144 255 json_regfetch(L, objectmt);
jbe@147 256 // push arraymt onto stack position 3:
jbe@144 257 json_regfetch(L, arraymt);
jbe@181 258 // push table for stack swapping onto stack position 5:
jbe@181 259 // (needed to avoid Lua stack overflows)
jbe@181 260 lua_newtable(L);
jbe@136 261 // main loop of parser:
jbe@136 262 json_import_loop:
jbe@136 263 // skip whitespace and store next character in variable 'c':
jbe@146 264 while (c = str[pos],
jbe@146 265 c == ' ' ||
jbe@146 266 c == '\f' ||
jbe@146 267 c == '\n' ||
jbe@146 268 c == '\r' ||
jbe@146 269 c == '\t' ||
jbe@146 270 c == '\v'
jbe@146 271 ) pos++;
jbe@170 272 // NOTE: variable c needs to be unsigned in the following code
jbe@136 273 // switch statement to handle certain (single) characters:
jbe@121 274 switch (c) {
jbe@136 275 // handle end of JSON document:
jbe@121 276 case 0:
jbe@136 277 // if end of JSON document was expected, then return top element of stack as result:
jbe@124 278 if (mode == JSON_STATE_END) return 1;
jbe@136 279 // otherwise, the JSON document was malformed:
jbe@167 280 if (level == 0) {
jbe@167 281 lua_pushnil(L);
jbe@167 282 lua_pushliteral(L, "Empty string");
jbe@167 283 } else {
jbe@167 284 json_import_unexpected_eof:
jbe@167 285 lua_pushnil(L);
jbe@167 286 lua_pushliteral(L, "Unexpected end of JSON document");
jbe@167 287 }
jbe@121 288 return 2;
jbe@181 289 // new JSON object or JSON array:
jbe@121 290 case '{':
jbe@181 291 case '[':
jbe@181 292 // if an encountered JSON object is not expected here, then return an error:
jbe@146 293 if (
jbe@181 294 c == '{' &&
jbe@181 295 mode != JSON_STATE_VALUE &&
jbe@181 296 mode != JSON_STATE_OBJECT_VALUE &&
jbe@181 297 mode != JSON_STATE_ARRAY_VALUE
jbe@181 298 ) goto json_import_syntax_error;
jbe@181 299 // if an encountered JSON array is not expected here, then return an error:
jbe@181 300 if (
jbe@181 301 c == '[' &&
jbe@146 302 mode != JSON_STATE_VALUE &&
jbe@146 303 mode != JSON_STATE_OBJECT_VALUE &&
jbe@146 304 mode != JSON_STATE_ARRAY_VALUE
jbe@146 305 ) goto json_import_syntax_error;
jbe@181 306 // consume input character:
jbe@181 307 pos++;
jbe@181 308 // limit nested levels:
jbe@181 309 if (level >= JSON_MAXDEPTH) {
jbe@181 310 lua_pushnil(L);
jbe@181 311 lua_pushfstring(L, "More than %d nested JSON levels", JSON_MAXDEPTH);
jbe@181 312 return 2;
jbe@181 313 }
jbe@181 314 // swap Lua stack entries for previous level to swap table:
jbe@181 315 // (avoids depth limitations due to Lua stack size)
jbe@181 316 if (level) {
jbe@181 317 lua_rawseti(L, json_import_stackswap_idx, ++stackswapidx);
jbe@181 318 lua_rawseti(L, json_import_stackswap_idx, ++stackswapidx);
jbe@181 319 lua_rawseti(L, json_import_stackswap_idx, ++stackswapidx);
jbe@181 320 }
jbe@181 321 // increment level:
jbe@181 322 level++;
jbe@181 323 // create JSON object or JSON array on stack:
jbe@136 324 lua_newtable(L);
jbe@181 325 // set metatable of JSON object or JSON array:
jbe@181 326 lua_pushvalue(L, c == '{' ? json_import_objectmt_idx : json_import_arraymt_idx);
jbe@125 327 lua_setmetatable(L, -2);
jbe@136 328 // create internal shadow table on stack:
jbe@136 329 lua_newtable(L);
jbe@146 330 // register internal shadow table:
jbe@193 331 lua_pushvalue(L, -1);
jbe@193 332 json_setshadow(L, -3);
jbe@181 333 // distinguish between JSON objects and JSON arrays:
jbe@181 334 if (c == '{') {
jbe@181 335 // if JSON object,
jbe@181 336 // expect object key (or end of object) to follow:
jbe@181 337 mode = JSON_STATE_OBJECT_KEY;
jbe@181 338 } else {
jbe@181 339 // if JSON array,
jbe@181 340 // expect array value (or end of array) to follow:
jbe@181 341 mode = JSON_STATE_ARRAY_VALUE;
jbe@181 342 // add nil as key (needed to keep stack balance) and as magic to detect arrays:
jbe@181 343 if (c == '[') lua_pushnil(L);
jbe@142 344 }
jbe@121 345 goto json_import_loop;
jbe@136 346 // end of JSON object:
jbe@121 347 case '}':
jbe@136 348 // if end of JSON object is not expected here, then return an error:
jbe@146 349 if (
jbe@146 350 mode != JSON_STATE_OBJECT_KEY &&
jbe@146 351 mode != JSON_STATE_OBJECT_SEPARATOR
jbe@146 352 ) goto json_import_syntax_error;
jbe@136 353 // jump to common code for end of JSON object and JSON array:
jbe@121 354 goto json_import_close;
jbe@136 355 // end of JSON array:
jbe@121 356 case ']':
jbe@136 357 // if end of JSON array is not expected here, then return an error:
jbe@146 358 if (
jbe@146 359 mode != JSON_STATE_ARRAY_VALUE &&
jbe@146 360 mode != JSON_STATE_ARRAY_SEPARATOR
jbe@146 361 ) goto json_import_syntax_error;
jbe@146 362 // pop nil key/magic (that was needed to keep stack balance):
jbe@140 363 lua_pop(L, 1);
jbe@136 364 // continue with common code for end of JSON object and JSON array:
jbe@136 365 // common code for end of JSON object or JSON array:
jbe@121 366 json_import_close:
jbe@136 367 // consume input character:
jbe@121 368 pos++;
jbe@136 369 // pop shadow table:
jbe@136 370 lua_pop(L, 1);
jbe@136 371 // check if nested:
jbe@121 372 if (--level) {
jbe@146 373 // if nested,
jbe@181 374 // restore previous stack elements from stack swap:
jbe@181 375 lua_rawgeti(L, json_import_stackswap_idx, stackswapidx--);
jbe@181 376 lua_insert(L, -2);
jbe@181 377 lua_rawgeti(L, json_import_stackswap_idx, stackswapidx--);
jbe@181 378 lua_insert(L, -2);
jbe@181 379 lua_rawgeti(L, json_import_stackswap_idx, stackswapidx--);
jbe@181 380 lua_insert(L, -2);
jbe@146 381 // check if outer(!) structure is an array or object:
jbe@140 382 if (lua_isnil(L, -2)) {
jbe@136 383 // select array value processing:
jbe@124 384 mode = JSON_STATE_ARRAY_VALUE;
jbe@121 385 } else {
jbe@136 386 // select object value processing:
jbe@124 387 mode = JSON_STATE_OBJECT_VALUE;
jbe@121 388 }
jbe@136 389 // store value in outer structure:
jbe@121 390 goto json_import_process_value;
jbe@121 391 }
jbe@136 392 // if not nested, then expect end of JSON document and continue with loop:
jbe@136 393 mode = JSON_STATE_END;
jbe@121 394 goto json_import_loop;
jbe@136 395 // key terminator:
jbe@121 396 case ':':
jbe@136 397 // if key terminator is not expected here, then return an error:
jbe@124 398 if (mode != JSON_STATE_OBJECT_KEY_TERMINATOR)
jbe@121 399 goto json_import_syntax_error;
jbe@136 400 // consume input character:
jbe@121 401 pos++;
jbe@146 402 // expect object value to follow:
jbe@124 403 mode = JSON_STATE_OBJECT_VALUE;
jbe@146 404 // continue with loop:
jbe@121 405 goto json_import_loop;
jbe@136 406 // value terminator (NOTE: trailing comma at end of value or key-value list is tolerated by this parser)
jbe@121 407 case ',':
jbe@146 408 // branch according to parser state:
jbe@124 409 if (mode == JSON_STATE_OBJECT_SEPARATOR) {
jbe@146 410 // expect an object key to follow:
jbe@124 411 mode = JSON_STATE_OBJECT_KEY;
jbe@124 412 } else if (mode == JSON_STATE_ARRAY_SEPARATOR) {
jbe@146 413 // expect an array value to follow:
jbe@124 414 mode = JSON_STATE_ARRAY_VALUE;
jbe@121 415 } else {
jbe@136 416 // if value terminator is not expected here, then return an error:
jbe@136 417 goto json_import_syntax_error;
jbe@121 418 }
jbe@136 419 // consume input character:
jbe@121 420 pos++;
jbe@136 421 // continue with loop:
jbe@121 422 goto json_import_loop;
jbe@136 423 // string literal:
jbe@121 424 case '"':
jbe@146 425 // consume quote character:
jbe@146 426 pos++;
jbe@162 427 // find last character in input string:
jbe@162 428 outlen = pos;
jbe@162 429 while ((c = str[outlen]) != '"') {
jbe@161 430 // consume one character:
jbe@162 431 outlen++;
jbe@161 432 // handle unexpected end of JSON document:
jbe@161 433 if (c == 0) goto json_import_unexpected_eof;
jbe@161 434 // consume one extra character when encountering an escaped quote:
jbe@162 435 else if (c == '\\' && str[outlen] == '"') outlen++;
jbe@161 436 }
jbe@162 437 // determine buffer length:
jbe@162 438 outlen -= pos;
jbe@161 439 // check if string is non empty:
jbe@162 440 if (outlen) {
jbe@161 441 // prepare buffer to decode string (with maximum possible length) and set write position to zero:
jbe@162 442 cbuf = luaL_buffinitsize(L, &luabuf, outlen);
jbe@162 443 outlen = 0;
jbe@161 444 // loop through the characters until encountering end quote:
jbe@161 445 while ((c = str[pos++]) != '"') {
jbe@162 446 // NOTE: unexpected end cannot happen anymore
jbe@162 447 if (c < 32 || c == 127) {
jbe@161 448 // do not allow ASCII control characters:
jbe@161 449 // NOTE: illegal UTF-8 sequences and extended control characters are not sanitized
jbe@161 450 // by this parser to allow different encodings than Unicode
jbe@161 451 lua_pushnil(L);
jbe@161 452 lua_pushliteral(L, "Unexpected control character in JSON string");
jbe@161 453 return 2;
jbe@161 454 } else if (c == '\\') {
jbe@161 455 // read next char after backslash escape:
jbe@161 456 c = str[pos++];
jbe@161 457 switch (c) {
jbe@161 458 // unexpected end-of-string:
jbe@161 459 case 0:
jbe@161 460 goto json_import_unexpected_eof;
jbe@161 461 // unescaping of quotation mark, slash, and backslash:
jbe@161 462 case '"':
jbe@161 463 case '/':
jbe@161 464 case '\\':
jbe@162 465 cbuf[outlen++] = c;
jbe@161 466 break;
jbe@161 467 // unescaping of backspace:
jbe@162 468 case 'b': cbuf[outlen++] = '\b'; break;
jbe@161 469 // unescaping of form-feed:
jbe@162 470 case 'f': cbuf[outlen++] = '\f'; break;
jbe@161 471 // unescaping of new-line:
jbe@162 472 case 'n': cbuf[outlen++] = '\n'; break;
jbe@161 473 // unescaping of carriage-return:
jbe@162 474 case 'r': cbuf[outlen++] = '\r'; break;
jbe@161 475 // unescaping of tabulator:
jbe@162 476 case 't': cbuf[outlen++] = '\t'; break;
jbe@161 477 // unescaping of UTF-16 characters
jbe@161 478 case 'u':
jbe@167 479 // decode 4 hex nibbles:
jbe@167 480 json_import_readhex(codepoint);
jbe@167 481 // handle surrogate character:
jbe@167 482 if (json_utf16_surrogate(codepoint)) {
jbe@167 483 // check if first surrogate is in valid range:
jbe@167 484 if (json_utf16_lead(codepoint)) {
jbe@167 485 // require second surrogate:
jbe@167 486 if ((c = str[pos++]) != '\\' || (c = str[pos++]) != 'u') {
jbe@167 487 if (c == 0) goto json_import_unexpected_eof;
jbe@167 488 else goto json_import_wrong_surrogate;
jbe@167 489 }
jbe@167 490 // read 4 hex nibbles of second surrogate character:
jbe@167 491 json_import_readhex(utf16tail);
jbe@167 492 // check if second surrogate is in valid range:
jbe@167 493 if (!json_utf16_tail(utf16tail)) goto json_import_wrong_surrogate;
jbe@167 494 // calculate codepoint:
jbe@167 495 codepoint = 0x10000 + (utf16tail - 0xDC00) + (codepoint - 0xD800) * 0x400;
jbe@167 496 } else {
jbe@167 497 // throw error for wrong surrogates:
jbe@167 498 json_import_wrong_surrogate:
jbe@167 499 lua_pushnil(L);
jbe@167 500 lua_pushliteral(L, "Illegal UTF-16 surrogate in JSON string escape sequence");
jbe@167 501 return 2;
jbe@167 502 }
jbe@167 503 }
jbe@167 504 // encode as UTF-8:
jbe@167 505 if (codepoint < 0x80) {
jbe@167 506 cbuf[outlen++] = (char)codepoint;
jbe@167 507 } else if (codepoint < 0x800) {
jbe@167 508 cbuf[outlen++] = (char)(0xc0 | (codepoint >> 6));
jbe@167 509 cbuf[outlen++] = (char)(0x80 | (codepoint & 0x3f));
jbe@167 510 } else if (codepoint < 0x10000) {
jbe@167 511 cbuf[outlen++] = (char)(0xe0 | (codepoint >> 12));
jbe@167 512 cbuf[outlen++] = (char)(0x80 | ((codepoint >> 6) & 0x3f));
jbe@167 513 cbuf[outlen++] = (char)(0x80 | (codepoint & 0x3f));
jbe@167 514 } else {
jbe@167 515 cbuf[outlen++] = (char)(0xf0 | (codepoint >> 18));
jbe@167 516 cbuf[outlen++] = (char)(0x80 | ((codepoint >> 12) & 0x3f));
jbe@167 517 cbuf[outlen++] = (char)(0x80 | ((codepoint >> 6) & 0x3f));
jbe@167 518 cbuf[outlen++] = (char)(0x80 | (codepoint & 0x3f));
jbe@167 519 }
jbe@167 520 break;
jbe@161 521 // unexpected escape sequence:
jbe@161 522 default:
jbe@167 523 json_import_unexpected_escape:
jbe@161 524 lua_pushnil(L);
jbe@161 525 lua_pushliteral(L, "Unexpected string escape sequence in JSON document");
jbe@161 526 return 2;
jbe@161 527 }
jbe@161 528 } else {
jbe@161 529 // normal character:
jbe@162 530 cbuf[outlen++] = c;
jbe@121 531 }
jbe@121 532 }
jbe@161 533 // process buffer to Lua string:
jbe@162 534 luaL_pushresultsize(&luabuf, outlen);
jbe@161 535 } else {
jbe@161 536 // if JSON string is empty,
jbe@161 537 // push empty Lua string:
jbe@161 538 lua_pushliteral(L, "");
jbe@167 539 // consume closing quote:
jbe@167 540 pos++;
jbe@121 541 }
jbe@136 542 // continue with processing of decoded string:
jbe@121 543 goto json_import_process_value;
jbe@121 544 }
jbe@136 545 // process values whose type is is not deducible from a single character:
jbe@136 546 if ((c >= '0' && c <= '9') || c == '-' || c == '+') {
jbe@146 547 // for numbers,
jbe@146 548 // use strtod() call to parse a (double precision) floating point number:
jbe@167 549 double numval;
jbe@122 550 char *endptr;
jbe@122 551 numval = strtod(str+pos, &endptr);
jbe@146 552 // catch parsing errors:
jbe@122 553 if (endptr == str+pos) goto json_import_syntax_error;
jbe@146 554 // consume characters that were parsed:
jbe@122 555 pos += endptr - (str+pos);
jbe@146 556 // push parsed (double precision) floating point number on Lua stack:
jbe@122 557 lua_pushnumber(L, numval);
jbe@122 558 } else if (!strncmp(str+pos, "true", 4)) {
jbe@136 559 // consume 4 input characters for "true":
jbe@121 560 pos += 4;
jbe@147 561 // put Lua true value onto stack:
jbe@136 562 lua_pushboolean(L, 1);
jbe@121 563 } else if (!strncmp(str+pos, "false", 5)) {
jbe@136 564 // consume 5 input characters for "false":
jbe@121 565 pos += 5;
jbe@147 566 // put Lua false value onto stack:
jbe@136 567 lua_pushboolean(L, 0);
jbe@121 568 } else if (!strncmp(str+pos, "null", 4)) {
jbe@136 569 // consume 4 input characters for "null":
jbe@136 570 pos += 4;
jbe@194 571 // push special null-marker onto stack:
jbe@194 572 json_pushnullmark(L);
jbe@121 573 } else {
jbe@136 574 // all other cases are a syntax error:
jbe@121 575 goto json_import_syntax_error;
jbe@121 576 }
jbe@136 577 // process a decoded value or key value pair (expected on top of Lua stack):
jbe@136 578 json_import_process_value:
jbe@121 579 switch (mode) {
jbe@136 580 // an object key has been read:
jbe@124 581 case JSON_STATE_OBJECT_KEY:
jbe@136 582 // if an object key is not a string, then this is a syntax error:
jbe@121 583 if (lua_type(L, -1) != LUA_TSTRING) goto json_import_syntax_error;
jbe@146 584 // expect key terminator to follow:
jbe@124 585 mode = JSON_STATE_OBJECT_KEY_TERMINATOR;
jbe@146 586 // continue with loop:
jbe@121 587 goto json_import_loop;
jbe@136 588 // a key value pair has been read:
jbe@124 589 case JSON_STATE_OBJECT_VALUE:
jbe@136 590 // store key value pair in outer shadow table:
jbe@130 591 lua_rawset(L, -3);
jbe@146 592 // expect value terminator (or end of object) to follow:
jbe@124 593 mode = JSON_STATE_OBJECT_SEPARATOR;
jbe@146 594 // continue with loop:
jbe@121 595 goto json_import_loop;
jbe@136 596 // an array value has been read:
jbe@124 597 case JSON_STATE_ARRAY_VALUE:
jbe@152 598 // get current array length:
jbe@152 599 arraylen = lua_rawlen(L, -3);
jbe@152 600 // throw error if array would exceed INT_MAX elements:
jbe@152 601 // TODO: Lua 5.3 may support more elements
jbe@152 602 if (arraylen >= INT_MAX) {
jbe@152 603 lua_pushnil(L);
jbe@152 604 lua_pushfstring(L, "Array exceeded length of %d elements", INT_MAX);
jbe@152 605 }
jbe@136 606 // store value in outer shadow table:
jbe@152 607 lua_rawseti(L, -3, arraylen + 1);
jbe@146 608 // expect value terminator (or end of object) to follow:
jbe@124 609 mode = JSON_STATE_ARRAY_SEPARATOR;
jbe@146 610 // continue with loop
jbe@121 611 goto json_import_loop;
jbe@136 612 // a single value has been read:
jbe@124 613 case JSON_STATE_VALUE:
jbe@136 614 // leave value on top of stack, expect end of JSON document, and continue with loop:
jbe@124 615 mode = JSON_STATE_END;
jbe@121 616 goto json_import_loop;
jbe@121 617 }
jbe@146 618 // syntax error handling (reachable by goto statement):
jbe@136 619 json_import_syntax_error:
jbe@121 620 lua_pushnil(L);
jbe@121 621 lua_pushliteral(L, "Syntax error in JSON document");
jbe@121 622 return 2;
jbe@121 623 }
jbe@121 624
jbe@146 625 // gets a value or its type from a JSON document (passed as first argument)
jbe@175 626 // using a path (passed as variable number of keys after the first argument):
jbe@137 627 static int json_path(lua_State *L, int type_mode) {
jbe@193 628 int stacktop; // number of arguments
jbe@193 629 int idx = 2; // stack index of current argument to process
jbe@173 630 // require at least one argument:
jbe@173 631 luaL_checkany(L, 1);
jbe@193 632 // store stack index of top of stack (number of arguments):
jbe@138 633 stacktop = lua_gettop(L);
jbe@146 634 // use first argument as "current value" (stored on top of stack):
jbe@193 635 lua_pushvalue(L, 1);
jbe@146 636 // process each "path key" (2nd argument and following arguments):
jbe@138 637 while (idx <= stacktop) {
jbe@146 638 // if "current value" (on top of stack) is nil, then the path cannot be walked and nil is returned:
jbe@137 639 if (lua_isnil(L, -1)) return 1;
jbe@137 640 // try to get shadow table of "current value":
jbe@193 641 json_getshadow(L, -1);
jbe@126 642 if (lua_isnil(L, -1)) {
jbe@137 643 // if no shadow table is found,
jbe@193 644 if (lua_type(L, -2) == LUA_TTABLE) {
jbe@146 645 // and if "current value" is a table,
jbe@193 646 // pop nil from stack:
jbe@146 647 lua_pop(L, 1);
jbe@137 648 // get "next value" using the "path key":
jbe@130 649 lua_pushvalue(L, idx++);
jbe@130 650 lua_gettable(L, -2);
jbe@130 651 } else {
jbe@137 652 // if "current value" is not a table,
jbe@146 653 // then the path cannot be walked and nil (already on top of stack) is returned:
jbe@137 654 return 1;
jbe@130 655 }
jbe@130 656 } else {
jbe@137 657 // if a shadow table is found,
jbe@137 658 // set "current value" to its shadow table:
jbe@130 659 lua_replace(L, -2);
jbe@137 660 // get "next value" using the "path key":
jbe@130 661 lua_pushvalue(L, idx++);
jbe@130 662 lua_rawget(L, -2);
jbe@126 663 }
jbe@137 664 // the "next value" replaces the "current value":
jbe@130 665 lua_replace(L, -2);
jbe@126 666 }
jbe@137 667 if (!type_mode) {
jbe@137 668 // if a value (and not its type) was requested,
jbe@137 669 // check if value is the null-marker, and store nil on top of Lua stack in that case:
jbe@155 670 if (json_isnullmark(L, -1)) lua_pushnil(L);
jbe@137 671 } else {
jbe@137 672 // if the type was requested,
jbe@137 673 // check if value is the null-marker:
jbe@155 674 if (json_isnullmark(L, -1)) {
jbe@137 675 // if yes, store string "null" on top of Lua stack:
jbe@130 676 lua_pushliteral(L, "null");
jbe@137 677 } else {
jbe@137 678 // otherwise,
jbe@138 679 // check if metatable indicates "object" or "array":
jbe@138 680 if (lua_getmetatable(L, -1)) {
jbe@144 681 json_regfetch(L, objectmt);
jbe@138 682 if (lua_rawequal(L, -2, -1)) {
jbe@146 683 // if value has metatable for JSON objects,
jbe@138 684 // return string "object":
jbe@138 685 lua_pushliteral(L, "object");
jbe@138 686 return 1;
jbe@138 687 }
jbe@144 688 json_regfetch(L, arraymt);
jbe@138 689 if (lua_rawequal(L, -3, -1)) {
jbe@146 690 // if value has metatable for JSON arrays,
jbe@146 691 // return string "object":
jbe@138 692 lua_pushliteral(L, "array");
jbe@138 693 return 1;
jbe@138 694 }
jbe@146 695 // remove 3 metatables (one of the value, two for comparison) from stack:
jbe@138 696 lua_pop(L, 3);
jbe@138 697 }
jbe@138 698 // otherwise, get the Lua type:
jbe@138 699 lua_pushstring(L, lua_typename(L, lua_type(L, -1)));
jbe@126 700 }
jbe@126 701 }
jbe@137 702 // return the top most value on the Lua stack:
jbe@137 703 return 1;
jbe@130 704 }
jbe@130 705
jbe@147 706 // gets a value from a JSON document (passed as first argument)
jbe@175 707 // using a path (passed as variable number of keys after the first argument):
jbe@130 708 static int json_get(lua_State *L) {
jbe@137 709 return json_path(L, 0);
jbe@130 710 }
jbe@130 711
jbe@147 712 // gets a value's type from a JSON document (passed as first argument)
jbe@175 713 // using a path (passed as variable number of keys after first the argument):
jbe@130 714 static int json_type(lua_State *L) {
jbe@137 715 return json_path(L, 1);
jbe@130 716 }
jbe@130 717
jbe@173 718 // special Lua stack indicies for json_set function:
jbe@193 719 #define json_set_objectmt_idx 1
jbe@193 720 #define json_set_arraymt_idx 2
jbe@173 721
jbe@173 722 // stack offset of arguments to json_set function:
jbe@193 723 #define json_set_idxshift 2
jbe@173 724
jbe@173 725 // sets a value (passed as second argument) in a JSON document (passed as first argument)
jbe@175 726 // using a path (passed as variable number of keys starting at third argument):
jbe@173 727 static int json_set(lua_State *L) {
jbe@193 728 int stacktop; // stack index of top of stack (after shifting)
jbe@193 729 int idx; // stack index of current argument to process
jbe@199 730 // require at least three arguments:
jbe@173 731 luaL_checkany(L, 1);
jbe@173 732 luaL_checkany(L, 2);
jbe@199 733 luaL_checkany(L, 3);
jbe@193 734 // insert objectmt into stack at position 1 (shifting the arguments):
jbe@173 735 json_regfetch(L, objectmt);
jbe@193 736 lua_insert(L, 1);
jbe@193 737 // insert arraymt into stack at position 2 (shifting the arguments):
jbe@193 738 json_regfetch(L, arraymt);
jbe@173 739 lua_insert(L, 2);
jbe@173 740 // store stack index of top of stack:
jbe@173 741 stacktop = lua_gettop(L);
jbe@173 742 // use nil as initial "parent value":
jbe@173 743 lua_pushnil(L);
jbe@173 744 // use first argument as "current value":
jbe@173 745 lua_pushvalue(L, 1 + json_set_idxshift);
jbe@173 746 // set all necessary values in path:
jbe@173 747 for (idx = 3 + json_set_idxshift; idx<=stacktop; idx++) {
jbe@173 748 // push metatable of "current value" onto stack:
jbe@173 749 if (!lua_getmetatable(L, -1)) lua_pushnil(L);
jbe@173 750 // distinguish according to type of path key:
jbe@173 751 switch (lua_type(L, idx)) {
jbe@173 752 case LUA_TSTRING:
jbe@173 753 // if path key is a string,
jbe@173 754 // check if "current value" is a JSON object (or table without metatable):
jbe@173 755 if (
jbe@173 756 lua_rawequal(L, -1, json_set_objectmt_idx) ||
jbe@173 757 (lua_isnil(L, -1) && lua_type(L, -2) == LUA_TTABLE)
jbe@173 758 ) {
jbe@173 759 // if "current value" is acceptable,
jbe@173 760 // pop metatable and leave "current value" on top of stack:
jbe@173 761 lua_pop(L, 1);
jbe@173 762 } else {
jbe@173 763 // if "current value" is not acceptable:
jbe@173 764 // pop metatable and "current value":
jbe@173 765 lua_pop(L, 2);
jbe@173 766 // throw error if parent element does not exist:
jbe@173 767 if (lua_isnil(L, -1)) return luaL_error(L, "Root element is not a JSON object");
jbe@173 768 // push new JSON object as "current value" onto stack:
jbe@193 769 json_createproxy(L);
jbe@173 770 // create and register shadow table:
jbe@173 771 lua_newtable(L);
jbe@193 772 json_setshadow(L, -2);
jbe@173 773 // set metatable of JSON object:
jbe@173 774 lua_pushvalue(L, json_set_objectmt_idx);
jbe@173 775 lua_setmetatable(L, -2);
jbe@173 776 // set entry in "parent value":
jbe@173 777 lua_pushvalue(L, idx-1);
jbe@173 778 lua_pushvalue(L, -2);
jbe@173 779 lua_settable(L, -4);
jbe@173 780 }
jbe@173 781 break;
jbe@173 782 case LUA_TNUMBER:
jbe@173 783 // if path key is a number,
jbe@173 784 // check if "current value" is a JSON array (or table without metatable):
jbe@173 785 if (
jbe@173 786 lua_rawequal(L, -1, json_set_arraymt_idx) ||
jbe@173 787 (lua_isnil(L, -1) && lua_type(L, -2) == LUA_TTABLE)
jbe@173 788 ) {
jbe@173 789 // if "current value" is acceptable,
jbe@173 790 // pop metatable and leave "current value" on top of stack:
jbe@173 791 lua_pop(L, 1);
jbe@173 792 } else {
jbe@173 793 // if "current value" is not acceptable:
jbe@173 794 // pop metatable and "current value":
jbe@173 795 lua_pop(L, 2);
jbe@173 796 // throw error if parent element does not exist:
jbe@173 797 if (lua_isnil(L, -1)) return luaL_error(L, "Root element is not a JSON array");
jbe@173 798 // push new JSON array as "current value" onto stack:
jbe@193 799 json_createproxy(L);
jbe@173 800 // create and register shadow table:
jbe@173 801 lua_newtable(L);
jbe@193 802 json_setshadow(L, -2);
jbe@173 803 // set metatable of JSON array:
jbe@173 804 lua_pushvalue(L, json_set_arraymt_idx);
jbe@173 805 lua_setmetatable(L, -2);
jbe@173 806 // set entry in "parent value":
jbe@173 807 lua_pushvalue(L, idx-1);
jbe@173 808 lua_pushvalue(L, -2);
jbe@173 809 lua_settable(L, -4);
jbe@173 810 }
jbe@173 811 break;
jbe@173 812 default:
jbe@173 813 return luaL_error(L, "Invalid path key of type %s", lua_typename(L, lua_type(L, idx)));
jbe@173 814 }
jbe@173 815 // check if last path element is being processed:
jbe@173 816 if (idx == stacktop) {
jbe@173 817 // if the last path element is being processed,
jbe@173 818 // set last path value in "current value" container:
jbe@173 819 lua_pushvalue(L, idx);
jbe@173 820 lua_pushvalue(L, 2 + json_set_idxshift);
jbe@173 821 lua_settable(L, -3);
jbe@173 822 } else {
jbe@173 823 // if the processed path element is not the last,
jbe@173 824 // use old "current value" as new "parent value"
jbe@173 825 lua_remove(L, -2);
jbe@173 826 // push new "current value" onto stack by performing a lookup:
jbe@173 827 lua_pushvalue(L, idx);
jbe@173 828 lua_gettable(L, -2);
jbe@173 829 }
jbe@173 830 }
jbe@173 831 // return first argument for convenience:
jbe@173 832 lua_settop(L, 1 + json_set_idxshift);
jbe@173 833 return 1;
jbe@173 834 }
jbe@173 835
jbe@147 836 // returns the length of a JSON array (or zero for a table without numeric keys):
jbe@130 837 static int json_len(lua_State *L) {
jbe@201 838 // require table as first argument:
jbe@201 839 luaL_checktype(L, 1, LUA_TTABLE);
jbe@147 840 // stack shall contain one function argument:
jbe@130 841 lua_settop(L, 1);
jbe@193 842 // push shadow table or nil onto stack:
jbe@193 843 json_getshadow(L, 1);
jbe@193 844 // pop nil from stack if no shadow table has been found:
jbe@193 845 if (lua_isnil(L, -1)) lua_pop(L, 1);
jbe@193 846 // return length of argument or shadow table:
jbe@193 847 lua_pushnumber(L, lua_rawlen(L, -1));
jbe@123 848 return 1;
jbe@123 849 }
jbe@123 850
jbe@175 851 // __index metamethod for JSON objects and JSON arrays:
jbe@130 852 static int json_index(lua_State *L) {
jbe@201 853 // require table as first argument:
jbe@201 854 luaL_checktype(L, 1, LUA_TTABLE);
jbe@148 855 // stack shall contain two function arguments:
jbe@130 856 lua_settop(L, 2);
jbe@193 857 // replace first argument with its shadow table
jbe@193 858 // or throw error if no shadow table is found:
jbe@193 859 json_getshadow(L, 1);
jbe@139 860 if (lua_isnil(L, -1)) return luaL_error(L, "Shadow table not found");
jbe@193 861 lua_replace(L, 1);
jbe@148 862 // use key passed as second argument to lookup value in shadow table:
jbe@193 863 lua_rawget(L, 1);
jbe@148 864 // if value is null-marker, then push nil onto stack:
jbe@193 865 if (json_isnullmark(L, 2)) lua_pushnil(L);
jbe@148 866 // return either looked up value, or nil
jbe@127 867 return 1;
jbe@127 868 }
jbe@127 869
jbe@175 870 // __newindex metamethod for JSON objects and JSON arrays:
jbe@130 871 static int json_newindex(lua_State *L) {
jbe@201 872 // require table as first argument
jbe@201 873 luaL_checktype(L, 1, LUA_TTABLE);
jbe@148 874 // stack shall contain three function arguments:
jbe@130 875 lua_settop(L, 3);
jbe@193 876 // replace first argument with its shadow table
jbe@193 877 // or throw error if no shadow table is found:
jbe@193 878 json_getshadow(L, 1);
jbe@130 879 if (lua_isnil(L, -1)) return luaL_error(L, "Shadow table not found");
jbe@130 880 lua_replace(L, 1);
jbe@193 881 // second and third argument to write to shadow table:
jbe@130 882 lua_rawset(L, 1);
jbe@148 883 // return nothing:
jbe@148 884 return 0;
jbe@121 885 }
jbe@121 886
jbe@175 887 // function returned as first value by json_pairs function:
jbe@135 888 static int json_pairs_iterfunc(lua_State *L) {
jbe@201 889 // require table as first argument
jbe@201 890 luaL_checktype(L, 1, LUA_TTABLE);
jbe@149 891 // stack shall contain two function arguments:
jbe@135 892 lua_settop(L, 2);
jbe@200 893 // get next key value pair from shadow table (argument 1) using previous key (argument 2)
jbe@149 894 // and return nothing if there is no next pair:
jbe@193 895 if (!lua_next(L, 1)) return 0;
jbe@149 896 // replace null-marker with nil:
jbe@155 897 if (json_isnullmark(L, -1)) {
jbe@135 898 lua_pop(L, 1);
jbe@135 899 lua_pushnil(L);
jbe@135 900 }
jbe@149 901 // return key and value (or key and nil, if null-marker was found):
jbe@135 902 return 2;
jbe@135 903 }
jbe@135 904
jbe@149 905 // returns a triple such that 'for key, value in pairs(obj) do ... end'
jbe@175 906 // iterates through all key value pairs (including JSON null values represented as Lua nil):
jbe@135 907 static int json_pairs(lua_State *L) {
jbe@201 908 // require table as first argument
jbe@201 909 luaL_checktype(L, 1, LUA_TTABLE);
jbe@200 910 // return triple of function json_pairs_iterfunc, shadow table of first argument, and nil:
jbe@139 911 lua_pushcfunction(L, json_pairs_iterfunc);
jbe@200 912 json_getshadow(L, 1);
jbe@200 913 if (lua_isnil(L, -1)) return luaL_error(L, "Shadow table not found");
jbe@135 914 lua_pushnil(L);
jbe@135 915 return 3;
jbe@135 916 }
jbe@135 917
jbe@175 918 // function returned as first value by json_ipairs function:
jbe@134 919 static int json_ipairs_iterfunc(lua_State *L) {
jbe@152 920 lua_Integer idx;
jbe@201 921 // require table as first argument
jbe@201 922 luaL_checktype(L, 1, LUA_TTABLE);
jbe@149 923 // stack shall contain two function arguments:
jbe@134 924 lua_settop(L, 2);
jbe@149 925 // calculate new index by incrementing second argument:
jbe@134 926 idx = lua_tointeger(L, 2) + 1;
jbe@200 927 // do integer lookup in shadow table and store result on stack position 3:
jbe@200 928 lua_rawgeti(L, 1, idx);
jbe@149 929 // return nothing if there was no value:
jbe@200 930 if (lua_isnil(L, 3)) return 0;
jbe@149 931 // return new index and
jbe@149 932 // either the looked up value if it is not equal to the null-marker
jbe@149 933 // or nil instead of null-marker:
jbe@134 934 lua_pushinteger(L, idx);
jbe@200 935 if (json_isnullmark(L, 3)) lua_pushnil(L);
jbe@200 936 else lua_pushvalue(L, 3);
jbe@134 937 return 2;
jbe@134 938 }
jbe@134 939
jbe@149 940 // returns a triple such that 'for idx, value in ipairs(ary) do ... end'
jbe@175 941 // iterates through all values (including JSON null values represented as Lua nil):
jbe@134 942 static int json_ipairs(lua_State *L) {
jbe@201 943 // require table as first argument
jbe@201 944 luaL_checktype(L, 1, LUA_TTABLE);
jbe@200 945 // return triple of function json_ipairs_iterfunc, shadow table of first argument, and zero:
jbe@139 946 lua_pushcfunction(L, json_ipairs_iterfunc);
jbe@200 947 json_getshadow(L, 1);
jbe@200 948 if (lua_isnil(L, -1)) return luaL_error(L, "Shadow table not found");
jbe@134 949 lua_pushinteger(L, 0);
jbe@134 950 return 3;
jbe@134 951 }
jbe@134 952
jbe@175 953 // datatype representing a table key:
jbe@175 954 // (used for sorting)
jbe@163 955 typedef struct {
jbe@163 956 size_t length;
jbe@163 957 const char *data;
jbe@163 958 } json_key_t;
jbe@163 959
jbe@175 960 // comparation function for table keys to be passed to qsort function:
jbe@163 961 static int json_key_cmp(json_key_t *key1, json_key_t *key2) {
jbe@163 962 size_t pos = 0;
jbe@163 963 unsigned char c1, c2;
jbe@163 964 while (1) {
jbe@163 965 if (key1->length > pos) {
jbe@163 966 if (key2->length > pos) {
jbe@163 967 c1 = key1->data[pos];
jbe@163 968 c2 = key2->data[pos];
jbe@163 969 if (c1 < c2) return -1;
jbe@163 970 else if (c1 > c2) return 1;
jbe@163 971 } else {
jbe@163 972 return 1;
jbe@163 973 }
jbe@163 974 } else {
jbe@163 975 if (key2->length > pos) {
jbe@163 976 return -1;
jbe@163 977 } else {
jbe@163 978 return 0;
jbe@163 979 }
jbe@163 980 }
jbe@163 981 pos++;
jbe@163 982 }
jbe@163 983 }
jbe@163 984
jbe@175 985 // constants for type detection of ambiguous tables:
jbe@154 986 #define JSON_TABLETYPE_UNKNOWN 0
jbe@154 987 #define JSON_TABLETYPE_OBJECT 1
jbe@154 988 #define JSON_TABLETYPE_ARRAY 2
jbe@154 989
jbe@183 990 typedef struct {
jbe@183 991 int type;
jbe@183 992 int pos;
jbe@183 993 int count;
jbe@183 994 json_key_t keys[1]; // or more
jbe@183 995 } json_container_t;
jbe@183 996
jbe@183 997 // special Lua stack indicies for json_export function:
jbe@183 998 #define json_export_value_idx 1
jbe@183 999 #define json_export_indentstring_idx 2
jbe@183 1000 #define json_export_objectmt_idx 3
jbe@183 1001 #define json_export_arraymt_idx 4
jbe@193 1002 #define json_export_stackswap_idx 5
jbe@193 1003 #define json_export_luacontainer_idx 6
jbe@193 1004 #define json_export_ccontainer_idx 7
jbe@193 1005 #define json_export_buffer_idx 8
jbe@164 1006
jbe@183 1007 // encodes a JSON document (passed as first argument)
jbe@187 1008 // optionally using indentation (indentation string or true passed as second argument)
jbe@183 1009 static int json_export(lua_State *L) {
jbe@183 1010 int pretty; // pretty printing on? (i.e. printing with indentation)
jbe@183 1011 luaL_Buffer buf; // Lua buffer containing result string
jbe@183 1012 lua_Number num; // number to encode
jbe@190 1013 char numstr[21]; // encoded number (sign, zero, point, 17 significant digits, and terminating NULL byte)
jbe@183 1014 const char *str; // string to encode
jbe@183 1015 size_t strlen; // length of string to encode
jbe@183 1016 size_t strpos ; // position in string or position of current key
jbe@183 1017 unsigned char c; // character to encode (unsigned!)
jbe@183 1018 char hexcode[7]; // store for unicode hex escape sequence
jbe@183 1019 // NOTE: 7 bytes due to backslash, character 'u', 4 hex digits, and terminating NULL byte
jbe@183 1020 int tabletype; // table type: unknown, JSON object, or JSON array
jbe@183 1021 size_t keycount = 0; // number of string keys in object
jbe@185 1022 json_key_t *key; // pointer to C structure containing a string key
jbe@183 1023 int level = 0; // current depth level
jbe@183 1024 int i; // iteration variable for level dependent repetitions
jbe@183 1025 int stackswapidx = 0; // elements in stack swap table
jbe@183 1026 int containerkey = 0; // temporarily set to 1, if a container key is being encoded
jbe@183 1027 json_container_t *container = NULL; // pointer to current C struct for container information
jbe@183 1028 // stack shall contain two function arguments:
jbe@183 1029 lua_settop(L, 2);
jbe@188 1030 // check if pretty printing (with indentation) is desired:
jbe@188 1031 if (lua_toboolean(L, json_export_indentstring_idx)) {
jbe@188 1032 // if yes,
jbe@188 1033 // set pretty variable to 1:
jbe@188 1034 pretty = 1;
jbe@188 1035 // check if second argument is a boolean (true):
jbe@188 1036 if (lua_isboolean(L, json_export_indentstring_idx)) {
jbe@188 1037 // if yes,
jbe@188 1038 // use default indentation if indentation argument is boolean true:
jbe@188 1039 lua_pushliteral(L, " ");
jbe@188 1040 lua_replace(L, json_export_indentstring_idx);
jbe@188 1041 } else {
jbe@188 1042 // if no,
jbe@188 1043 // require second argument to be a string:
jbe@188 1044 luaL_checktype(L, json_export_indentstring_idx, LUA_TSTRING);
jbe@188 1045 }
jbe@188 1046 } else {
jbe@188 1047 // if no,
jbe@188 1048 // set pretty variable to 0:
jbe@188 1049 pretty = 0;
jbe@157 1050 }
jbe@183 1051 // push objectmt onto stack position 3:
jbe@183 1052 json_regfetch(L, objectmt);
jbe@183 1053 // push arraymt onto stack position 4:
jbe@183 1054 json_regfetch(L, arraymt);
jbe@193 1055 // push table for stack swapping onto stack position 5:
jbe@183 1056 lua_newtable(L);
jbe@193 1057 // create placeholders on stack positions 6 through 7:
jbe@187 1058 lua_settop(L, json_export_buffer_idx);
jbe@183 1059 // create Lua string buffer:
jbe@183 1060 luaL_buffinit(L, &buf);
jbe@183 1061 // loop:
jbe@183 1062 while (1) {
jbe@183 1063 // if value to encode is the null-marker, then treat it the same as nil:
jbe@183 1064 if (json_isnullmark(L, json_export_value_idx)) {
jbe@183 1065 lua_pushnil(L);
jbe@183 1066 lua_replace(L, json_export_value_idx);
jbe@164 1067 }
jbe@183 1068 // distinguish between different Lua types:
jbe@183 1069 switch (lua_type(L, json_export_value_idx)) {
jbe@183 1070 // value to encode is nil:
jbe@183 1071 case LUA_TNIL:
jbe@183 1072 // add string "null" to output buffer:
jbe@183 1073 luaL_addstring(&buf, "null");
jbe@183 1074 break;
jbe@183 1075 // value to encode is of type number:
jbe@183 1076 case LUA_TNUMBER:
jbe@183 1077 // convert value to double precision number:
jbe@183 1078 num = lua_tonumber(L, json_export_value_idx);
jbe@183 1079 // throw error if number is not-a-number:
jbe@183 1080 if (isnan(num)) return luaL_error(L, "JSON export not possible for NaN value");
jbe@183 1081 // throw error if number is positive or negative infinity:
jbe@183 1082 if (isinf(num)) return luaL_error(L, "JSON export not possible for infinite numbers");
jbe@191 1083 // determine necessary precision to represent double precision floating point number:
jbe@192 1084 sprintf(numstr, "%.16g", num);
jbe@191 1085 if (strtod(numstr, NULL) != num) sprintf(numstr, "%.17g", num);
jbe@191 1086 // add string encoding of the number to the output buffer:
jbe@189 1087 luaL_addstring(&buf, numstr);
jbe@183 1088 break;
jbe@183 1089 // value to encode is of type boolean:
jbe@183 1090 case LUA_TBOOLEAN:
jbe@183 1091 // add string "true" or "false" according to boolean value:
jbe@183 1092 luaL_addstring(&buf, lua_toboolean(L, json_export_value_idx) ? "true" : "false");
jbe@183 1093 break;
jbe@183 1094 // value to encode is of type string:
jbe@183 1095 case LUA_TSTRING:
jbe@183 1096 // add quoted and escaped string to output buffer:
jbe@183 1097 str = lua_tolstring(L, json_export_value_idx, &strlen);
jbe@183 1098 luaL_addchar(&buf, '"');
jbe@183 1099 strpos = 0;
jbe@183 1100 while (strpos < strlen) {
jbe@183 1101 c = str[strpos++];
jbe@183 1102 if (c == '"') luaL_addstring(&buf, "\\\"");
jbe@183 1103 else if (c == '\\') luaL_addstring(&buf, "\\\\");
jbe@183 1104 else if (c == 127) luaL_addstring(&buf, "\\u007F");
jbe@183 1105 else if (c >= 32) luaL_addchar(&buf, c);
jbe@183 1106 else if (c == '\b') luaL_addstring(&buf, "\\b");
jbe@183 1107 else if (c == '\f') luaL_addstring(&buf, "\\f");
jbe@183 1108 else if (c == '\n') luaL_addstring(&buf, "\\n");
jbe@183 1109 else if (c == '\r') luaL_addstring(&buf, "\\r");
jbe@183 1110 else if (c == '\t') luaL_addstring(&buf, "\\t");
jbe@183 1111 else if (c == '\v') luaL_addstring(&buf, "\\v");
jbe@183 1112 else {
jbe@183 1113 sprintf(hexcode, "\\u%04X", c);
jbe@183 1114 luaL_addstring(&buf, hexcode);
jbe@154 1115 }
jbe@154 1116 }
jbe@183 1117 luaL_addchar(&buf, '"');
jbe@183 1118 break;
jbe@183 1119 // value to encode is of type table (this includes JSON objects and JSON arrays):
jbe@183 1120 case LUA_TTABLE:
jbe@183 1121 // use table's metatable to try to determine type of table:
jbe@183 1122 tabletype = JSON_TABLETYPE_UNKNOWN;
jbe@188 1123 if (lua_getmetatable(L, json_export_value_idx)) {
jbe@183 1124 if (lua_rawequal(L, -1, json_export_objectmt_idx)) {
jbe@183 1125 tabletype = JSON_TABLETYPE_OBJECT;
jbe@183 1126 } else {
jbe@183 1127 if (lua_rawequal(L, -1, json_export_arraymt_idx)) {
jbe@183 1128 tabletype = JSON_TABLETYPE_ARRAY;
jbe@183 1129 } else {
jbe@183 1130 return luaL_error(L, "JSON export not possible for tables with nonsupported metatable");
jbe@183 1131 }
jbe@183 1132 }
jbe@183 1133 // reset stack (pop metatable from stack):
jbe@183 1134 lua_pop(L, 1);
jbe@183 1135 }
jbe@193 1136 // replace table with its shadow table if existent:
jbe@193 1137 json_getshadow(L, json_export_value_idx);
jbe@183 1138 if (lua_isnil(L, -1)) lua_pop(L, 1);
jbe@193 1139 else lua_replace(L, json_export_value_idx);
jbe@187 1140 // check if type of table is still undetermined
jbe@187 1141 // and optionally calculate number of string keys (keycount)
jbe@187 1142 // or set keycount to zero:
jbe@186 1143 keycount = 0;
jbe@183 1144 if (tabletype == JSON_TABLETYPE_UNKNOWN) {
jbe@187 1145 // if type of table is undetermined,
jbe@187 1146 // iterate over all keys:
jbe@188 1147 for (lua_pushnil(L); lua_next(L, json_export_value_idx); lua_pop(L, 1)) {
jbe@183 1148 switch (lua_type(L, -2)) {
jbe@183 1149 case LUA_TSTRING:
jbe@183 1150 // for string keys,
jbe@183 1151 // increase keycount (may avoid another iteration):
jbe@183 1152 keycount++;
jbe@183 1153 // if type of table was unknown, then type of table is a JSON object now:
jbe@183 1154 if (tabletype == JSON_TABLETYPE_UNKNOWN) tabletype = JSON_TABLETYPE_OBJECT;
jbe@183 1155 // if type of table was a JSON array, then the type of table is ambiguous now
jbe@183 1156 // and an error is thrown:
jbe@183 1157 else if (tabletype == JSON_TABLETYPE_ARRAY) goto json_export_tabletype_error;
jbe@183 1158 break;
jbe@183 1159 case LUA_TNUMBER:
jbe@183 1160 // for numeric keys,
jbe@183 1161 // if type of table was unknown, then type of table is a JSON array now:
jbe@183 1162 if (tabletype == JSON_TABLETYPE_UNKNOWN) tabletype = JSON_TABLETYPE_ARRAY;
jbe@183 1163 // if type of table was a JSON object, then the type of table is ambiguous now
jbe@183 1164 // and an error is thrown:
jbe@183 1165 else if (tabletype == JSON_TABLETYPE_OBJECT) goto json_export_tabletype_error;
jbe@183 1166 break;
jbe@183 1167 }
jbe@164 1168 }
jbe@163 1169 }
jbe@183 1170 // raise error if too many nested levels:
jbe@183 1171 if (level >= JSON_MAXDEPTH) {
jbe@183 1172 return luaL_error(L, "More than %d nested JSON levels", JSON_MAXDEPTH);
jbe@163 1173 }
jbe@183 1174 // store previous container information (if existent) on stack swap
jbe@183 1175 // and increase level variable:
jbe@183 1176 if (level++) {
jbe@183 1177 lua_pushvalue(L, json_export_luacontainer_idx);
jbe@183 1178 lua_rawseti(L, json_export_stackswap_idx, ++stackswapidx);
jbe@183 1179 lua_pushvalue(L, json_export_ccontainer_idx);
jbe@183 1180 lua_rawseti(L, json_export_stackswap_idx, ++stackswapidx);
jbe@183 1181 }
jbe@188 1182 // use value as current container:
jbe@188 1183 lua_pushvalue(L, json_export_value_idx);
jbe@188 1184 lua_replace(L, json_export_luacontainer_idx);
jbe@183 1185 // distinguish between JSON objects and JSON arrays:
jbe@183 1186 switch (tabletype) {
jbe@183 1187 // JSON object:
jbe@183 1188 case JSON_TABLETYPE_OBJECT:
jbe@183 1189 // calculate count of string keys unless it has been calculated before:
jbe@183 1190 if (!keycount) {
jbe@183 1191 for (lua_pushnil(L); lua_next(L, json_export_luacontainer_idx); lua_pop(L, 1)) {
jbe@183 1192 if (lua_type(L, -2) == LUA_TSTRING) keycount++;
jbe@164 1193 }
jbe@164 1194 }
jbe@186 1195 // allocate memory for C structure containing string keys and container iteration state:
jbe@186 1196 container = lua_newuserdata(L, sizeof(json_container_t) + (keycount-1) * sizeof(json_key_t));
jbe@187 1197 // store reference to C structure on designated stack position:
jbe@186 1198 lua_replace(L, json_export_ccontainer_idx);
jbe@186 1199 // initialize C structure for container state:
jbe@186 1200 container->type = JSON_TABLETYPE_OBJECT;
jbe@186 1201 container->count = keycount;
jbe@186 1202 container->pos = 0;
jbe@187 1203 // check if object contains any keys:
jbe@183 1204 if (keycount) {
jbe@187 1205 // if yes,
jbe@187 1206 // copy all string keys to the C structure (and reset container->pos again):
jbe@183 1207 for (lua_pushnil(L); lua_next(L, json_export_luacontainer_idx); lua_pop(L, 1)) {
jbe@183 1208 if (lua_type(L, -2) == LUA_TSTRING) {
jbe@183 1209 json_key_t *key = &container->keys[container->pos++];
jbe@183 1210 key->data = lua_tolstring(L, -2, &key->length);
jbe@183 1211 }
jbe@183 1212 }
jbe@183 1213 container->pos = 0;
jbe@183 1214 // sort C array using quicksort:
jbe@183 1215 qsort(container->keys, keycount, sizeof(json_key_t), (void *)json_key_cmp);
jbe@154 1216 }
jbe@183 1217 // add opening bracket to output buffer:
jbe@183 1218 luaL_addchar(&buf, '{');
jbe@183 1219 break;
jbe@183 1220 // JSON array:
jbe@183 1221 case JSON_TABLETYPE_ARRAY:
jbe@187 1222 // allocate memory for C structure for container iteration state:
jbe@183 1223 container = lua_newuserdata(L, sizeof(json_container_t) - sizeof(json_key_t));
jbe@187 1224 // store reference to C structure on designated stack position:
jbe@183 1225 lua_replace(L, json_export_ccontainer_idx);
jbe@187 1226 // initialize C structure for container state:
jbe@183 1227 container->type = JSON_TABLETYPE_ARRAY;
jbe@183 1228 container->pos = 0;
jbe@183 1229 // add opening bracket to output buffer:
jbe@183 1230 luaL_addchar(&buf, '[');
jbe@183 1231 break;
jbe@183 1232 default:
jbe@183 1233 // throw error if table type is unknown:
jbe@183 1234 json_export_tabletype_error:
jbe@183 1235 return luaL_error(L, "JSON export not possible for ambiguous table (cannot decide whether it is an object or array)");
jbe@183 1236 }
jbe@183 1237 break;
jbe@183 1238 default:
jbe@183 1239 // all other datatypes are considered an error:
jbe@183 1240 return luaL_error(L, "JSON export not possible for values of type \"%s\"", lua_typename(L, lua_type(L, json_export_value_idx)));
jbe@183 1241 }
jbe@187 1242 // check if a container is being processed:
jbe@183 1243 if (container) {
jbe@187 1244 // if yes,
jbe@187 1245 // execute code for container iteration:
jbe@184 1246 json_export_container:
jbe@187 1247 // distinguish between JSON objects and JSON arrays:
jbe@183 1248 switch (container->type) {
jbe@187 1249 // JSON object:
jbe@183 1250 case JSON_TABLETYPE_OBJECT:
jbe@187 1251 // finish iteration if all string keys have been processed:
jbe@185 1252 if (container->pos == container->count) goto json_export_close;
jbe@187 1253 // push current string key on top of stack:
jbe@185 1254 key = &container->keys[container->pos];
jbe@185 1255 lua_pushlstring(L, key->data, key->length);
jbe@187 1256 // check if the key has already been exported:
jbe@185 1257 if (!containerkey) {
jbe@187 1258 // if no,
jbe@187 1259 // add a comma to the output buffer if necessary:
jbe@185 1260 if (container->pos) luaL_addchar(&buf, ',');
jbe@187 1261 // set containerkey variable to true:
jbe@185 1262 containerkey = 1;
jbe@183 1263 } else {
jbe@187 1264 // if a key has already been exported,
jbe@187 1265 // add a colon to the output buffer:
jbe@185 1266 luaL_addchar(&buf, ':');
jbe@187 1267 // add a space to the output buffer for pretty results:
jbe@185 1268 if (pretty) luaL_addchar(&buf, ' ');
jbe@187 1269 // replace string key on top of stack with corresponding value:
jbe@185 1270 lua_rawget(L, json_export_luacontainer_idx);
jbe@187 1271 // reset containerkey variable
jbe@185 1272 containerkey = 0;
jbe@187 1273 // increase number of processed key value pairs:
jbe@185 1274 container->pos++;
jbe@163 1275 }
jbe@187 1276 // store key or value on top of stack in designated stack position:
jbe@185 1277 lua_replace(L, json_export_value_idx);
jbe@183 1278 break;
jbe@187 1279 // JSON array:
jbe@183 1280 case JSON_TABLETYPE_ARRAY:
jbe@187 1281 // store next value in designated stack position:
jbe@185 1282 lua_rawgeti(L, json_export_luacontainer_idx, container->pos+1);
jbe@183 1283 lua_replace(L, json_export_value_idx);
jbe@187 1284 // finish iteration if value is nil:
jbe@185 1285 if (lua_isnil(L, json_export_value_idx)) goto json_export_close;
jbe@187 1286 // add a comma to the output buffer if necessary:
jbe@185 1287 if (container->pos) luaL_addchar(&buf, ',');
jbe@187 1288 // increase number of processed values:
jbe@185 1289 container->pos++;
jbe@183 1290 break;
jbe@187 1291 // common code for closing JSON objects or JSON arrays:
jbe@183 1292 json_export_close:
jbe@187 1293 // decrement level variable:
jbe@185 1294 level--;
jbe@187 1295 // handle indentation for pretty results:
jbe@187 1296 if (pretty && container->pos) {
jbe@187 1297 luaL_addchar(&buf, '\n');
jbe@187 1298 for (i=0; i<level; i++) {
jbe@187 1299 lua_pushvalue(L, json_export_indentstring_idx);
jbe@187 1300 luaL_addvalue(&buf);
jbe@185 1301 }
jbe@164 1302 }
jbe@187 1303 // add closing bracket to output buffer:
jbe@185 1304 luaL_addchar(&buf, container->type == JSON_TABLETYPE_OBJECT ? '}' : ']');
jbe@187 1305 // finish export if last level has been closed:
jbe@185 1306 if (!level) goto json_export_finish;
jbe@187 1307 // otherwise,
jbe@187 1308 // recall previous container information from stack swap
jbe@187 1309 // and set C pointer to corresponding C struct:
jbe@185 1310 lua_rawgeti(L, json_export_stackswap_idx, stackswapidx--);
jbe@185 1311 lua_replace(L, json_export_ccontainer_idx);
jbe@185 1312 container = lua_touserdata(L, json_export_ccontainer_idx);
jbe@185 1313 lua_rawgeti(L, json_export_stackswap_idx, stackswapidx--);
jbe@185 1314 lua_replace(L, json_export_luacontainer_idx);
jbe@187 1315 // repeat code for container iteration:
jbe@185 1316 goto json_export_container;
jbe@164 1317 }
jbe@184 1318 // handle indentation for pretty results:
jbe@185 1319 if (pretty && (containerkey || container->type == JSON_TABLETYPE_ARRAY)) {
jbe@185 1320 luaL_addchar(&buf, '\n');
jbe@185 1321 for (i=0; i<level; i++) {
jbe@185 1322 lua_pushvalue(L, json_export_indentstring_idx);
jbe@185 1323 luaL_addvalue(&buf);
jbe@164 1324 }
jbe@154 1325 }
jbe@183 1326 } else {
jbe@187 1327 // if no container is being processed,
jbe@187 1328 // finish export:
jbe@185 1329 json_export_finish:
jbe@185 1330 // for pretty results, add final newline character if outermost container is processed:
jbe@185 1331 if (pretty) luaL_addchar(&buf, '\n');
jbe@187 1332 // create and return Lua string from buffer contents
jbe@154 1333 luaL_pushresult(&buf);
jbe@154 1334 return 1;
jbe@154 1335 }
jbe@154 1336 }
jbe@164 1337 }
jbe@164 1338
jbe@149 1339 // functions in library module:
jbe@121 1340 static const struct luaL_Reg json_module_functions[] = {
jbe@133 1341 {"object", json_object},
jbe@173 1342 {"array", json_array},
jbe@121 1343 {"import", json_import},
jbe@154 1344 {"export", json_export},
jbe@173 1345 {"get", json_get},
jbe@173 1346 {"type", json_type},
jbe@173 1347 {"set", json_set},
jbe@121 1348 {NULL, NULL}
jbe@121 1349 };
jbe@121 1350
jbe@149 1351 // metamethods for JSON objects, JSON arrays, and unknown JSON collections (object or array):
jbe@126 1352 static const struct luaL_Reg json_metatable_functions[] = {
jbe@130 1353 {"__len", json_len},
jbe@130 1354 {"__index", json_index},
jbe@130 1355 {"__newindex", json_newindex},
jbe@135 1356 {"__pairs", json_pairs},
jbe@134 1357 {"__ipairs", json_ipairs},
jbe@160 1358 {"__tostring", json_export},
jbe@126 1359 {NULL, NULL}
jbe@126 1360 };
jbe@126 1361
jbe@157 1362 // metamethods for JSON null marker:
jbe@157 1363 static const struct luaL_Reg json_nullmark_metamethods[] = {
jbe@157 1364 {"__tostring", json_nullmark_tostring},
jbe@157 1365 {NULL, NULL}
jbe@157 1366 };
jbe@157 1367
jbe@149 1368 // initializes json library:
jbe@121 1369 int luaopen_json(lua_State *L) {
jbe@149 1370 // empty stack:
jbe@126 1371 lua_settop(L, 0);
jbe@149 1372 // push library module onto stack position 1:
jbe@149 1373 lua_newtable(L);
jbe@149 1374 // register library functions:
jbe@149 1375 luaL_setfuncs(L, json_module_functions, 0);
jbe@149 1376 // create and store objectmt:
jbe@138 1377 lua_newtable(L);
jbe@138 1378 luaL_setfuncs(L, json_metatable_functions, 0);
jbe@144 1379 json_regstore(L, objectmt);
jbe@149 1380 // create and store arraymt:
jbe@138 1381 lua_newtable(L);
jbe@138 1382 luaL_setfuncs(L, json_metatable_functions, 0);
jbe@144 1383 json_regstore(L, arraymt);
jbe@157 1384 // set metatable of null marker and make it available through library module:
jbe@157 1385 json_pushnullmark(L);
jbe@157 1386 lua_newtable(L);
jbe@157 1387 luaL_setfuncs(L, json_nullmark_metamethods, 0);
jbe@157 1388 lua_setmetatable(L, -2);
jbe@157 1389 lua_setfield(L, 1, "null");
jbe@157 1390 // return library module (that's expected on top of stack):
jbe@121 1391 return 1;
jbe@121 1392 }

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