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annotate libraries/json/json.c @ 193:0014a7c22013

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Improved performance of JSON library by storing shadow tables directly via a lightuserdata key instead of using ephemeron tables
author jbe
date Mon Aug 11 13:18:49 2014 +0200 (2014-08-11)
parents 33c8f7029cfa
children 654ddbcc49d0
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@169 51 #define json_convert_source_idx 1
jbe@169 52 #define json_convert_iterator_idx 2
jbe@169 53 #define json_convert_output_idx 3
jbe@169 54 #define json_convert_shadow_idx 4
jbe@172 55 #define json_convert_iterfun_idx 5
jbe@172 56 #define json_convert_itertbl_idx 6
jbe@169 57
jbe@175 58 // converts a Lua table (or any other iterable value) to a JSON object or JSON array:
jbe@169 59 // (does never modify the argument, returns an empty object or array if argument is nil)
jbe@169 60 static int json_convert(lua_State *L, int array) {
jbe@171 61 int arrayidx = 0;
jbe@171 62 // determine is argument is given:
jbe@169 63 if (lua_isnoneornil(L, json_convert_source_idx)) {
jbe@171 64 // if no argument is given (or if argument is nil),
jbe@193 65 // create proxy table with shadow table, and leave proxy table on top of stack:
jbe@193 66 json_createproxy(L);
jbe@169 67 lua_newtable(L);
jbe@193 68 json_setshadow(L, -2);
jbe@169 69 } else {
jbe@171 70 // if an argument was given,
jbe@193 71 // stack shall contain only one function argument:
jbe@171 72 lua_settop(L, 1);
jbe@193 73 // check if there is an iterator function in its metatable:
jbe@193 74 if (luaL_getmetafield(L, json_convert_source_idx, array ? "__ipairs" : "__pairs")) {
jbe@193 75 // if there is an iterator function,
jbe@193 76 // leave it on stack position 2 and verify its type:
jbe@193 77 if (lua_type(L, json_convert_iterator_idx) != LUA_TFUNCTION)
jbe@169 78 return luaL_error(L, "%s metamethod is not a function", array ? "__ipairs" : "__pairs");
jbe@169 79 } else {
jbe@193 80 // if there is no iterator function,
jbe@193 81 // verify the type of the argument itself:
jbe@193 82 luaL_checktype(L, json_convert_source_idx, LUA_TTABLE);
jbe@193 83 // push nil onto stack position 2:
jbe@169 84 lua_pushnil(L);
jbe@143 85 }
jbe@171 86 // create result table on stack position 3:
jbe@193 87 json_createproxy(L);
jbe@169 88 // create shadow table on stack position 4:
jbe@169 89 lua_newtable(L);
jbe@193 90 lua_pushvalue(L, -1);
jbe@193 91 json_setshadow(L, -3);
jbe@171 92 // check if iterator function exists:
jbe@169 93 if (lua_isnil(L, json_convert_iterator_idx)) {
jbe@171 94 // if there is no iterator function,
jbe@171 95 // distinguish between objects and arrays:
jbe@171 96 if (array == 0) {
jbe@171 97 // for an object, copy all string key value pairs to shadow table:
jbe@171 98 for (lua_pushnil(L); lua_next(L, json_convert_source_idx); lua_pop(L, 1)) {
jbe@171 99 if (lua_type(L, -2) == LUA_TSTRING) {
jbe@171 100 lua_pushvalue(L, -2);
jbe@171 101 lua_pushvalue(L, -2);
jbe@171 102 lua_rawset(L, json_convert_shadow_idx);
jbe@171 103 }
jbe@171 104 }
jbe@171 105 } else {
jbe@171 106 // for an array, copy consecutive integer value pairs to shadow table:
jbe@171 107 while (1) {
jbe@175 108 // throw error if array would exceed INT_MAX elements:
jbe@171 109 // TODO: Lua 5.3 may support more elements
jbe@171 110 if (arrayidx == INT_MAX) {
jbe@171 111 lua_pushnumber(L, (size_t)INT_MAX+1);
jbe@171 112 lua_rawget(L, json_convert_source_idx);
jbe@171 113 if (lua_isnil(L, -1)) break;
jbe@171 114 return luaL_error(L, "Array exceeded length of %d elements", INT_MAX);
jbe@171 115 }
jbe@175 116 // get next array entry:
jbe@171 117 arrayidx++;
jbe@171 118 lua_rawgeti(L, json_convert_source_idx, arrayidx);
jbe@175 119 // break if value is nil:
jbe@171 120 if (lua_isnil(L, -1)) break;
jbe@175 121 // store value in shadow table:
jbe@171 122 lua_rawseti(L, json_convert_shadow_idx, arrayidx);
jbe@171 123 }
jbe@169 124 }
jbe@169 125 } else {
jbe@172 126 // if there is an iterator function,
jbe@172 127 // call iterator function with source value (first argument)
jbe@172 128 // and store 3 result values on stack positions 5 through 7:
jbe@172 129 lua_pushvalue(L, json_convert_iterator_idx);
jbe@172 130 lua_pushvalue(L, 1);
jbe@172 131 lua_call(L, 1, 3);
jbe@175 132 // iterate through key value pairs and store some of them in shadow table
jbe@174 133 // while replacing nil values with null-marker:
jbe@172 134 while (1) {
jbe@175 135 // call iterfun function:
jbe@172 136 lua_pushvalue(L, json_convert_iterfun_idx);
jbe@172 137 lua_pushvalue(L, json_convert_itertbl_idx);
jbe@172 138 lua_pushvalue(L, -3);
jbe@172 139 lua_remove(L, -4);
jbe@172 140 lua_call(L, 2, 2);
jbe@175 141 // break iteration loop if key is nil:
jbe@172 142 if (lua_isnil(L, -2)) break;
jbe@175 143 // store key value pair only if key type is correct:
jbe@172 144 if (lua_type(L, -2) == (array ? LUA_TNUMBER : LUA_TSTRING)) {
jbe@175 145 // if key type is correct,
jbe@175 146 // push key onto stack:
jbe@172 147 lua_pushvalue(L, -2);
jbe@175 148 // if value is nil, push null-marker onto stack (as value):
jbe@174 149 if (lua_isnil(L, -2)) json_pushnullmark(L);
jbe@175 150 // else push value onto stack:
jbe@174 151 else lua_pushvalue(L, -2);
jbe@175 152 // set key value pair in shadow table:
jbe@172 153 lua_rawset(L, json_convert_shadow_idx);
jbe@172 154 }
jbe@175 155 // pop value from stack, but leave key on stack:
jbe@172 156 lua_pop(L, 1);
jbe@172 157 }
jbe@143 158 }
jbe@171 159 // let result table be on top of stack:
jbe@169 160 lua_settop(L, json_convert_output_idx);
jbe@136 161 }
jbe@171 162 // set metatable (for result table on top of stack):
jbe@171 163 if (array == 0) json_regfetch(L, objectmt);
jbe@171 164 else json_regfetch(L, arraymt);
jbe@169 165 lua_setmetatable(L, -2);
jbe@171 166 // return table on top of stack:
jbe@136 167 return 1;
jbe@136 168 }
jbe@136 169
jbe@175 170 // converts a Lua table (or any other iterable value) to a JSON object:
jbe@175 171 // (does never modify the argument, returns an empty object or array if argument is nil)
jbe@136 172 static int json_object(lua_State *L) {
jbe@169 173 return json_convert(L, 0);
jbe@136 174 }
jbe@136 175
jbe@175 176 // converts a Lua table (or any other iterable value) to a JSON array:
jbe@175 177 // (does never modify the argument, returns an empty object or array if argument is nil)
jbe@136 178 static int json_array(lua_State *L) {
jbe@169 179 return json_convert(L, 1);
jbe@136 180 }
jbe@136 181
jbe@145 182 // internal states of JSON parser:
jbe@124 183 #define JSON_STATE_VALUE 0
jbe@124 184 #define JSON_STATE_OBJECT_KEY 1
jbe@124 185 #define JSON_STATE_OBJECT_KEY_TERMINATOR 2
jbe@124 186 #define JSON_STATE_OBJECT_VALUE 3
jbe@124 187 #define JSON_STATE_OBJECT_SEPARATOR 4
jbe@124 188 #define JSON_STATE_ARRAY_VALUE 5
jbe@124 189 #define JSON_STATE_ARRAY_SEPARATOR 6
jbe@124 190 #define JSON_STATE_END 7
jbe@121 191
jbe@145 192 // special Lua stack indicies for json_import function:
jbe@138 193 #define json_import_objectmt_idx 2
jbe@138 194 #define json_import_arraymt_idx 3
jbe@193 195 #define json_import_stackswap_idx 4
jbe@138 196
jbe@168 197 // macros for hex decoding:
jbe@168 198 #define json_utf16_surrogate(x) ((x) >= 0xD800 && (x) <= 0xDFFF)
jbe@168 199 #define json_utf16_lead(x) ((x) >= 0xD800 && (x) <= 0xDBFF)
jbe@168 200 #define json_utf16_tail(x) ((x) >= 0xDC00 && (x) <= 0xDFFF)
jbe@167 201 #define json_import_readhex(x) \
jbe@167 202 do { \
jbe@167 203 x = 0; \
jbe@167 204 for (i=0; i<4; i++) { \
jbe@167 205 x <<= 4; \
jbe@167 206 c = str[pos++]; \
jbe@167 207 if (c >= '0' && c <= '9') x += c - '0'; \
jbe@167 208 else if (c >= 'A' && c <= 'F') x += c - 'A' + 10; \
jbe@167 209 else if (c >= 'a' && c <= 'f') x += c - 'a' + 10; \
jbe@167 210 else if (c == 0) goto json_import_unexpected_eof; \
jbe@167 211 else goto json_import_unexpected_escape; \
jbe@167 212 } \
jbe@167 213 } while (0)
jbe@167 214
jbe@136 215 // decodes a JSON document:
jbe@121 216 static int json_import(lua_State *L) {
jbe@181 217 int stackswapidx = 0; // elements in stack swap table
jbe@181 218 int i; // loop variable
jbe@181 219 const char *str; // string to parse
jbe@181 220 size_t total; // total length of string to parse
jbe@181 221 size_t pos = 0; // current position in string to parse
jbe@181 222 size_t level = 0; // nested levels of objects/arrays currently being processed
jbe@145 223 int mode = JSON_STATE_VALUE; // state of parser (i.e. "what's expected next?")
jbe@181 224 unsigned char c; // variable to store a single character to be processed (unsigned!)
jbe@181 225 luaL_Buffer luabuf; // Lua buffer to decode JSON string values
jbe@181 226 char *cbuf; // C buffer to decode JSON string values
jbe@181 227 size_t outlen; // maximum length or write position of C buffer
jbe@181 228 long codepoint; // decoded UTF-16 character or higher codepoint
jbe@181 229 long utf16tail; // second decoded UTF-16 character (surrogate tail)
jbe@181 230 size_t arraylen; // variable to temporarily store the array length
jbe@166 231 // require string as argument and convert to C string with length information:
jbe@166 232 str = luaL_checklstring(L, 1, &total);
jbe@166 233 // if string contains a NULL byte, this is a syntax error
jbe@166 234 if (strlen(str) != total) goto json_import_syntax_error;
jbe@147 235 // stack shall contain one function argument:
jbe@138 236 lua_settop(L, 1);
jbe@147 237 // push objectmt onto stack position 2:
jbe@144 238 json_regfetch(L, objectmt);
jbe@147 239 // push arraymt onto stack position 3:
jbe@144 240 json_regfetch(L, arraymt);
jbe@181 241 // push table for stack swapping onto stack position 5:
jbe@181 242 // (needed to avoid Lua stack overflows)
jbe@181 243 lua_newtable(L);
jbe@136 244 // main loop of parser:
jbe@136 245 json_import_loop:
jbe@136 246 // skip whitespace and store next character in variable 'c':
jbe@146 247 while (c = str[pos],
jbe@146 248 c == ' ' ||
jbe@146 249 c == '\f' ||
jbe@146 250 c == '\n' ||
jbe@146 251 c == '\r' ||
jbe@146 252 c == '\t' ||
jbe@146 253 c == '\v'
jbe@146 254 ) pos++;
jbe@170 255 // NOTE: variable c needs to be unsigned in the following code
jbe@136 256 // switch statement to handle certain (single) characters:
jbe@121 257 switch (c) {
jbe@136 258 // handle end of JSON document:
jbe@121 259 case 0:
jbe@136 260 // if end of JSON document was expected, then return top element of stack as result:
jbe@124 261 if (mode == JSON_STATE_END) return 1;
jbe@136 262 // otherwise, the JSON document was malformed:
jbe@167 263 if (level == 0) {
jbe@167 264 lua_pushnil(L);
jbe@167 265 lua_pushliteral(L, "Empty string");
jbe@167 266 } else {
jbe@167 267 json_import_unexpected_eof:
jbe@167 268 lua_pushnil(L);
jbe@167 269 lua_pushliteral(L, "Unexpected end of JSON document");
jbe@167 270 }
jbe@121 271 return 2;
jbe@181 272 // new JSON object or JSON array:
jbe@121 273 case '{':
jbe@181 274 case '[':
jbe@181 275 // if an encountered JSON object is not expected here, then return an error:
jbe@146 276 if (
jbe@181 277 c == '{' &&
jbe@181 278 mode != JSON_STATE_VALUE &&
jbe@181 279 mode != JSON_STATE_OBJECT_VALUE &&
jbe@181 280 mode != JSON_STATE_ARRAY_VALUE
jbe@181 281 ) goto json_import_syntax_error;
jbe@181 282 // if an encountered JSON array is not expected here, then return an error:
jbe@181 283 if (
jbe@181 284 c == '[' &&
jbe@146 285 mode != JSON_STATE_VALUE &&
jbe@146 286 mode != JSON_STATE_OBJECT_VALUE &&
jbe@146 287 mode != JSON_STATE_ARRAY_VALUE
jbe@146 288 ) goto json_import_syntax_error;
jbe@181 289 // consume input character:
jbe@181 290 pos++;
jbe@181 291 // limit nested levels:
jbe@181 292 if (level >= JSON_MAXDEPTH) {
jbe@181 293 lua_pushnil(L);
jbe@181 294 lua_pushfstring(L, "More than %d nested JSON levels", JSON_MAXDEPTH);
jbe@181 295 return 2;
jbe@181 296 }
jbe@181 297 // swap Lua stack entries for previous level to swap table:
jbe@181 298 // (avoids depth limitations due to Lua stack size)
jbe@181 299 if (level) {
jbe@181 300 lua_rawseti(L, json_import_stackswap_idx, ++stackswapidx);
jbe@181 301 lua_rawseti(L, json_import_stackswap_idx, ++stackswapidx);
jbe@181 302 lua_rawseti(L, json_import_stackswap_idx, ++stackswapidx);
jbe@181 303 }
jbe@181 304 // increment level:
jbe@181 305 level++;
jbe@181 306 // create JSON object or JSON array on stack:
jbe@136 307 lua_newtable(L);
jbe@181 308 // set metatable of JSON object or JSON array:
jbe@181 309 lua_pushvalue(L, c == '{' ? json_import_objectmt_idx : json_import_arraymt_idx);
jbe@125 310 lua_setmetatable(L, -2);
jbe@136 311 // create internal shadow table on stack:
jbe@136 312 lua_newtable(L);
jbe@146 313 // register internal shadow table:
jbe@193 314 lua_pushvalue(L, -1);
jbe@193 315 json_setshadow(L, -3);
jbe@181 316 // distinguish between JSON objects and JSON arrays:
jbe@181 317 if (c == '{') {
jbe@181 318 // if JSON object,
jbe@181 319 // expect object key (or end of object) to follow:
jbe@181 320 mode = JSON_STATE_OBJECT_KEY;
jbe@181 321 } else {
jbe@181 322 // if JSON array,
jbe@181 323 // expect array value (or end of array) to follow:
jbe@181 324 mode = JSON_STATE_ARRAY_VALUE;
jbe@181 325 // add nil as key (needed to keep stack balance) and as magic to detect arrays:
jbe@181 326 if (c == '[') lua_pushnil(L);
jbe@142 327 }
jbe@121 328 goto json_import_loop;
jbe@136 329 // end of JSON object:
jbe@121 330 case '}':
jbe@136 331 // if end of JSON object is not expected here, then return an error:
jbe@146 332 if (
jbe@146 333 mode != JSON_STATE_OBJECT_KEY &&
jbe@146 334 mode != JSON_STATE_OBJECT_SEPARATOR
jbe@146 335 ) goto json_import_syntax_error;
jbe@136 336 // jump to common code for end of JSON object and JSON array:
jbe@121 337 goto json_import_close;
jbe@136 338 // end of JSON array:
jbe@121 339 case ']':
jbe@136 340 // if end of JSON array is not expected here, then return an error:
jbe@146 341 if (
jbe@146 342 mode != JSON_STATE_ARRAY_VALUE &&
jbe@146 343 mode != JSON_STATE_ARRAY_SEPARATOR
jbe@146 344 ) goto json_import_syntax_error;
jbe@146 345 // pop nil key/magic (that was needed to keep stack balance):
jbe@140 346 lua_pop(L, 1);
jbe@136 347 // continue with common code for end of JSON object and JSON array:
jbe@136 348 // common code for end of JSON object or JSON array:
jbe@121 349 json_import_close:
jbe@136 350 // consume input character:
jbe@121 351 pos++;
jbe@136 352 // pop shadow table:
jbe@136 353 lua_pop(L, 1);
jbe@136 354 // check if nested:
jbe@121 355 if (--level) {
jbe@146 356 // if nested,
jbe@181 357 // restore previous stack elements from stack swap:
jbe@181 358 lua_rawgeti(L, json_import_stackswap_idx, stackswapidx--);
jbe@181 359 lua_insert(L, -2);
jbe@181 360 lua_rawgeti(L, json_import_stackswap_idx, stackswapidx--);
jbe@181 361 lua_insert(L, -2);
jbe@181 362 lua_rawgeti(L, json_import_stackswap_idx, stackswapidx--);
jbe@181 363 lua_insert(L, -2);
jbe@146 364 // check if outer(!) structure is an array or object:
jbe@140 365 if (lua_isnil(L, -2)) {
jbe@136 366 // select array value processing:
jbe@124 367 mode = JSON_STATE_ARRAY_VALUE;
jbe@121 368 } else {
jbe@136 369 // select object value processing:
jbe@124 370 mode = JSON_STATE_OBJECT_VALUE;
jbe@121 371 }
jbe@136 372 // store value in outer structure:
jbe@121 373 goto json_import_process_value;
jbe@121 374 }
jbe@136 375 // if not nested, then expect end of JSON document and continue with loop:
jbe@136 376 mode = JSON_STATE_END;
jbe@121 377 goto json_import_loop;
jbe@136 378 // key terminator:
jbe@121 379 case ':':
jbe@136 380 // if key terminator is not expected here, then return an error:
jbe@124 381 if (mode != JSON_STATE_OBJECT_KEY_TERMINATOR)
jbe@121 382 goto json_import_syntax_error;
jbe@136 383 // consume input character:
jbe@121 384 pos++;
jbe@146 385 // expect object value to follow:
jbe@124 386 mode = JSON_STATE_OBJECT_VALUE;
jbe@146 387 // continue with loop:
jbe@121 388 goto json_import_loop;
jbe@136 389 // value terminator (NOTE: trailing comma at end of value or key-value list is tolerated by this parser)
jbe@121 390 case ',':
jbe@146 391 // branch according to parser state:
jbe@124 392 if (mode == JSON_STATE_OBJECT_SEPARATOR) {
jbe@146 393 // expect an object key to follow:
jbe@124 394 mode = JSON_STATE_OBJECT_KEY;
jbe@124 395 } else if (mode == JSON_STATE_ARRAY_SEPARATOR) {
jbe@146 396 // expect an array value to follow:
jbe@124 397 mode = JSON_STATE_ARRAY_VALUE;
jbe@121 398 } else {
jbe@136 399 // if value terminator is not expected here, then return an error:
jbe@136 400 goto json_import_syntax_error;
jbe@121 401 }
jbe@136 402 // consume input character:
jbe@121 403 pos++;
jbe@136 404 // continue with loop:
jbe@121 405 goto json_import_loop;
jbe@136 406 // string literal:
jbe@121 407 case '"':
jbe@146 408 // consume quote character:
jbe@146 409 pos++;
jbe@162 410 // find last character in input string:
jbe@162 411 outlen = pos;
jbe@162 412 while ((c = str[outlen]) != '"') {
jbe@161 413 // consume one character:
jbe@162 414 outlen++;
jbe@161 415 // handle unexpected end of JSON document:
jbe@161 416 if (c == 0) goto json_import_unexpected_eof;
jbe@161 417 // consume one extra character when encountering an escaped quote:
jbe@162 418 else if (c == '\\' && str[outlen] == '"') outlen++;
jbe@161 419 }
jbe@162 420 // determine buffer length:
jbe@162 421 outlen -= pos;
jbe@161 422 // check if string is non empty:
jbe@162 423 if (outlen) {
jbe@161 424 // prepare buffer to decode string (with maximum possible length) and set write position to zero:
jbe@162 425 cbuf = luaL_buffinitsize(L, &luabuf, outlen);
jbe@162 426 outlen = 0;
jbe@161 427 // loop through the characters until encountering end quote:
jbe@161 428 while ((c = str[pos++]) != '"') {
jbe@162 429 // NOTE: unexpected end cannot happen anymore
jbe@162 430 if (c < 32 || c == 127) {
jbe@161 431 // do not allow ASCII control characters:
jbe@161 432 // NOTE: illegal UTF-8 sequences and extended control characters are not sanitized
jbe@161 433 // by this parser to allow different encodings than Unicode
jbe@161 434 lua_pushnil(L);
jbe@161 435 lua_pushliteral(L, "Unexpected control character in JSON string");
jbe@161 436 return 2;
jbe@161 437 } else if (c == '\\') {
jbe@161 438 // read next char after backslash escape:
jbe@161 439 c = str[pos++];
jbe@161 440 switch (c) {
jbe@161 441 // unexpected end-of-string:
jbe@161 442 case 0:
jbe@161 443 goto json_import_unexpected_eof;
jbe@161 444 // unescaping of quotation mark, slash, and backslash:
jbe@161 445 case '"':
jbe@161 446 case '/':
jbe@161 447 case '\\':
jbe@162 448 cbuf[outlen++] = c;
jbe@161 449 break;
jbe@161 450 // unescaping of backspace:
jbe@162 451 case 'b': cbuf[outlen++] = '\b'; break;
jbe@161 452 // unescaping of form-feed:
jbe@162 453 case 'f': cbuf[outlen++] = '\f'; break;
jbe@161 454 // unescaping of new-line:
jbe@162 455 case 'n': cbuf[outlen++] = '\n'; break;
jbe@161 456 // unescaping of carriage-return:
jbe@162 457 case 'r': cbuf[outlen++] = '\r'; break;
jbe@161 458 // unescaping of tabulator:
jbe@162 459 case 't': cbuf[outlen++] = '\t'; break;
jbe@161 460 // unescaping of UTF-16 characters
jbe@161 461 case 'u':
jbe@167 462 // decode 4 hex nibbles:
jbe@167 463 json_import_readhex(codepoint);
jbe@167 464 // handle surrogate character:
jbe@167 465 if (json_utf16_surrogate(codepoint)) {
jbe@167 466 // check if first surrogate is in valid range:
jbe@167 467 if (json_utf16_lead(codepoint)) {
jbe@167 468 // require second surrogate:
jbe@167 469 if ((c = str[pos++]) != '\\' || (c = str[pos++]) != 'u') {
jbe@167 470 if (c == 0) goto json_import_unexpected_eof;
jbe@167 471 else goto json_import_wrong_surrogate;
jbe@167 472 }
jbe@167 473 // read 4 hex nibbles of second surrogate character:
jbe@167 474 json_import_readhex(utf16tail);
jbe@167 475 // check if second surrogate is in valid range:
jbe@167 476 if (!json_utf16_tail(utf16tail)) goto json_import_wrong_surrogate;
jbe@167 477 // calculate codepoint:
jbe@167 478 codepoint = 0x10000 + (utf16tail - 0xDC00) + (codepoint - 0xD800) * 0x400;
jbe@167 479 } else {
jbe@167 480 // throw error for wrong surrogates:
jbe@167 481 json_import_wrong_surrogate:
jbe@167 482 lua_pushnil(L);
jbe@167 483 lua_pushliteral(L, "Illegal UTF-16 surrogate in JSON string escape sequence");
jbe@167 484 return 2;
jbe@167 485 }
jbe@167 486 }
jbe@167 487 // encode as UTF-8:
jbe@167 488 if (codepoint < 0x80) {
jbe@167 489 cbuf[outlen++] = (char)codepoint;
jbe@167 490 } else if (codepoint < 0x800) {
jbe@167 491 cbuf[outlen++] = (char)(0xc0 | (codepoint >> 6));
jbe@167 492 cbuf[outlen++] = (char)(0x80 | (codepoint & 0x3f));
jbe@167 493 } else if (codepoint < 0x10000) {
jbe@167 494 cbuf[outlen++] = (char)(0xe0 | (codepoint >> 12));
jbe@167 495 cbuf[outlen++] = (char)(0x80 | ((codepoint >> 6) & 0x3f));
jbe@167 496 cbuf[outlen++] = (char)(0x80 | (codepoint & 0x3f));
jbe@167 497 } else {
jbe@167 498 cbuf[outlen++] = (char)(0xf0 | (codepoint >> 18));
jbe@167 499 cbuf[outlen++] = (char)(0x80 | ((codepoint >> 12) & 0x3f));
jbe@167 500 cbuf[outlen++] = (char)(0x80 | ((codepoint >> 6) & 0x3f));
jbe@167 501 cbuf[outlen++] = (char)(0x80 | (codepoint & 0x3f));
jbe@167 502 }
jbe@167 503 break;
jbe@161 504 // unexpected escape sequence:
jbe@161 505 default:
jbe@167 506 json_import_unexpected_escape:
jbe@161 507 lua_pushnil(L);
jbe@161 508 lua_pushliteral(L, "Unexpected string escape sequence in JSON document");
jbe@161 509 return 2;
jbe@161 510 }
jbe@161 511 } else {
jbe@161 512 // normal character:
jbe@162 513 cbuf[outlen++] = c;
jbe@121 514 }
jbe@121 515 }
jbe@161 516 // process buffer to Lua string:
jbe@162 517 luaL_pushresultsize(&luabuf, outlen);
jbe@161 518 } else {
jbe@161 519 // if JSON string is empty,
jbe@161 520 // push empty Lua string:
jbe@161 521 lua_pushliteral(L, "");
jbe@167 522 // consume closing quote:
jbe@167 523 pos++;
jbe@121 524 }
jbe@136 525 // continue with processing of decoded string:
jbe@121 526 goto json_import_process_value;
jbe@121 527 }
jbe@136 528 // process values whose type is is not deducible from a single character:
jbe@136 529 if ((c >= '0' && c <= '9') || c == '-' || c == '+') {
jbe@146 530 // for numbers,
jbe@146 531 // use strtod() call to parse a (double precision) floating point number:
jbe@167 532 double numval;
jbe@122 533 char *endptr;
jbe@122 534 numval = strtod(str+pos, &endptr);
jbe@146 535 // catch parsing errors:
jbe@122 536 if (endptr == str+pos) goto json_import_syntax_error;
jbe@146 537 // consume characters that were parsed:
jbe@122 538 pos += endptr - (str+pos);
jbe@146 539 // push parsed (double precision) floating point number on Lua stack:
jbe@122 540 lua_pushnumber(L, numval);
jbe@122 541 } else if (!strncmp(str+pos, "true", 4)) {
jbe@136 542 // consume 4 input characters for "true":
jbe@121 543 pos += 4;
jbe@147 544 // put Lua true value onto stack:
jbe@136 545 lua_pushboolean(L, 1);
jbe@121 546 } else if (!strncmp(str+pos, "false", 5)) {
jbe@136 547 // consume 5 input characters for "false":
jbe@121 548 pos += 5;
jbe@147 549 // put Lua false value onto stack:
jbe@136 550 lua_pushboolean(L, 0);
jbe@121 551 } else if (!strncmp(str+pos, "null", 4)) {
jbe@136 552 // consume 4 input characters for "null":
jbe@136 553 pos += 4;
jbe@153 554 // different behavor for top-level and sub-levels:
jbe@153 555 if (level) {
jbe@153 556 // if sub-level,
jbe@153 557 // push special null-marker onto stack:
jbe@155 558 json_pushnullmark(L);
jbe@153 559 } else {
jbe@153 560 // if top-level,
jbe@153 561 // push nil onto stack:
jbe@153 562 lua_pushnil(L);
jbe@153 563 }
jbe@121 564 } else {
jbe@136 565 // all other cases are a syntax error:
jbe@121 566 goto json_import_syntax_error;
jbe@121 567 }
jbe@136 568 // process a decoded value or key value pair (expected on top of Lua stack):
jbe@136 569 json_import_process_value:
jbe@121 570 switch (mode) {
jbe@136 571 // an object key has been read:
jbe@124 572 case JSON_STATE_OBJECT_KEY:
jbe@136 573 // if an object key is not a string, then this is a syntax error:
jbe@121 574 if (lua_type(L, -1) != LUA_TSTRING) goto json_import_syntax_error;
jbe@146 575 // expect key terminator to follow:
jbe@124 576 mode = JSON_STATE_OBJECT_KEY_TERMINATOR;
jbe@146 577 // continue with loop:
jbe@121 578 goto json_import_loop;
jbe@136 579 // a key value pair has been read:
jbe@124 580 case JSON_STATE_OBJECT_VALUE:
jbe@136 581 // store key value pair in outer shadow table:
jbe@130 582 lua_rawset(L, -3);
jbe@146 583 // expect value terminator (or end of object) to follow:
jbe@124 584 mode = JSON_STATE_OBJECT_SEPARATOR;
jbe@146 585 // continue with loop:
jbe@121 586 goto json_import_loop;
jbe@136 587 // an array value has been read:
jbe@124 588 case JSON_STATE_ARRAY_VALUE:
jbe@152 589 // get current array length:
jbe@152 590 arraylen = lua_rawlen(L, -3);
jbe@152 591 // throw error if array would exceed INT_MAX elements:
jbe@152 592 // TODO: Lua 5.3 may support more elements
jbe@152 593 if (arraylen >= INT_MAX) {
jbe@152 594 lua_pushnil(L);
jbe@152 595 lua_pushfstring(L, "Array exceeded length of %d elements", INT_MAX);
jbe@152 596 }
jbe@136 597 // store value in outer shadow table:
jbe@152 598 lua_rawseti(L, -3, arraylen + 1);
jbe@146 599 // expect value terminator (or end of object) to follow:
jbe@124 600 mode = JSON_STATE_ARRAY_SEPARATOR;
jbe@146 601 // continue with loop
jbe@121 602 goto json_import_loop;
jbe@136 603 // a single value has been read:
jbe@124 604 case JSON_STATE_VALUE:
jbe@136 605 // leave value on top of stack, expect end of JSON document, and continue with loop:
jbe@124 606 mode = JSON_STATE_END;
jbe@121 607 goto json_import_loop;
jbe@121 608 }
jbe@146 609 // syntax error handling (reachable by goto statement):
jbe@136 610 json_import_syntax_error:
jbe@121 611 lua_pushnil(L);
jbe@121 612 lua_pushliteral(L, "Syntax error in JSON document");
jbe@121 613 return 2;
jbe@121 614 }
jbe@121 615
jbe@146 616 // gets a value or its type from a JSON document (passed as first argument)
jbe@175 617 // using a path (passed as variable number of keys after the first argument):
jbe@137 618 static int json_path(lua_State *L, int type_mode) {
jbe@193 619 int stacktop; // number of arguments
jbe@193 620 int idx = 2; // stack index of current argument to process
jbe@173 621 // require at least one argument:
jbe@173 622 luaL_checkany(L, 1);
jbe@193 623 // store stack index of top of stack (number of arguments):
jbe@138 624 stacktop = lua_gettop(L);
jbe@146 625 // use first argument as "current value" (stored on top of stack):
jbe@193 626 lua_pushvalue(L, 1);
jbe@146 627 // process each "path key" (2nd argument and following arguments):
jbe@138 628 while (idx <= stacktop) {
jbe@146 629 // if "current value" (on top of stack) is nil, then the path cannot be walked and nil is returned:
jbe@137 630 if (lua_isnil(L, -1)) return 1;
jbe@137 631 // try to get shadow table of "current value":
jbe@193 632 json_getshadow(L, -1);
jbe@126 633 if (lua_isnil(L, -1)) {
jbe@137 634 // if no shadow table is found,
jbe@193 635 if (lua_type(L, -2) == LUA_TTABLE) {
jbe@146 636 // and if "current value" is a table,
jbe@193 637 // pop nil from stack:
jbe@146 638 lua_pop(L, 1);
jbe@137 639 // get "next value" using the "path key":
jbe@130 640 lua_pushvalue(L, idx++);
jbe@130 641 lua_gettable(L, -2);
jbe@130 642 } else {
jbe@137 643 // if "current value" is not a table,
jbe@146 644 // then the path cannot be walked and nil (already on top of stack) is returned:
jbe@137 645 return 1;
jbe@130 646 }
jbe@130 647 } else {
jbe@137 648 // if a shadow table is found,
jbe@137 649 // set "current value" to its shadow table:
jbe@130 650 lua_replace(L, -2);
jbe@137 651 // get "next value" using the "path key":
jbe@130 652 lua_pushvalue(L, idx++);
jbe@130 653 lua_rawget(L, -2);
jbe@126 654 }
jbe@137 655 // the "next value" replaces the "current value":
jbe@130 656 lua_replace(L, -2);
jbe@126 657 }
jbe@137 658 if (!type_mode) {
jbe@137 659 // if a value (and not its type) was requested,
jbe@137 660 // check if value is the null-marker, and store nil on top of Lua stack in that case:
jbe@155 661 if (json_isnullmark(L, -1)) lua_pushnil(L);
jbe@137 662 } else {
jbe@137 663 // if the type was requested,
jbe@137 664 // check if value is the null-marker:
jbe@155 665 if (json_isnullmark(L, -1)) {
jbe@137 666 // if yes, store string "null" on top of Lua stack:
jbe@130 667 lua_pushliteral(L, "null");
jbe@137 668 } else {
jbe@137 669 // otherwise,
jbe@138 670 // check if metatable indicates "object" or "array":
jbe@138 671 if (lua_getmetatable(L, -1)) {
jbe@144 672 json_regfetch(L, objectmt);
jbe@138 673 if (lua_rawequal(L, -2, -1)) {
jbe@146 674 // if value has metatable for JSON objects,
jbe@138 675 // return string "object":
jbe@138 676 lua_pushliteral(L, "object");
jbe@138 677 return 1;
jbe@138 678 }
jbe@144 679 json_regfetch(L, arraymt);
jbe@138 680 if (lua_rawequal(L, -3, -1)) {
jbe@146 681 // if value has metatable for JSON arrays,
jbe@146 682 // return string "object":
jbe@138 683 lua_pushliteral(L, "array");
jbe@138 684 return 1;
jbe@138 685 }
jbe@146 686 // remove 3 metatables (one of the value, two for comparison) from stack:
jbe@138 687 lua_pop(L, 3);
jbe@138 688 }
jbe@138 689 // otherwise, get the Lua type:
jbe@138 690 lua_pushstring(L, lua_typename(L, lua_type(L, -1)));
jbe@126 691 }
jbe@126 692 }
jbe@137 693 // return the top most value on the Lua stack:
jbe@137 694 return 1;
jbe@130 695 }
jbe@130 696
jbe@147 697 // gets a value from a JSON document (passed as first argument)
jbe@175 698 // using a path (passed as variable number of keys after the first argument):
jbe@130 699 static int json_get(lua_State *L) {
jbe@137 700 return json_path(L, 0);
jbe@130 701 }
jbe@130 702
jbe@147 703 // gets a value's type from a JSON document (passed as first argument)
jbe@175 704 // using a path (passed as variable number of keys after first the argument):
jbe@130 705 static int json_type(lua_State *L) {
jbe@137 706 return json_path(L, 1);
jbe@130 707 }
jbe@130 708
jbe@173 709 // special Lua stack indicies for json_set function:
jbe@193 710 #define json_set_objectmt_idx 1
jbe@193 711 #define json_set_arraymt_idx 2
jbe@173 712
jbe@173 713 // stack offset of arguments to json_set function:
jbe@193 714 #define json_set_idxshift 2
jbe@173 715
jbe@173 716 // sets a value (passed as second argument) in a JSON document (passed as first argument)
jbe@175 717 // using a path (passed as variable number of keys starting at third argument):
jbe@173 718 static int json_set(lua_State *L) {
jbe@193 719 int stacktop; // stack index of top of stack (after shifting)
jbe@193 720 int idx; // stack index of current argument to process
jbe@173 721 // require at least two arguments:
jbe@173 722 luaL_checkany(L, 1);
jbe@173 723 luaL_checkany(L, 2);
jbe@193 724 // insert objectmt into stack at position 1 (shifting the arguments):
jbe@173 725 json_regfetch(L, objectmt);
jbe@193 726 lua_insert(L, 1);
jbe@193 727 // insert arraymt into stack at position 2 (shifting the arguments):
jbe@193 728 json_regfetch(L, arraymt);
jbe@173 729 lua_insert(L, 2);
jbe@173 730 // store stack index of top of stack:
jbe@173 731 stacktop = lua_gettop(L);
jbe@173 732 // use nil as initial "parent value":
jbe@173 733 lua_pushnil(L);
jbe@173 734 // use first argument as "current value":
jbe@173 735 lua_pushvalue(L, 1 + json_set_idxshift);
jbe@173 736 // set all necessary values in path:
jbe@173 737 for (idx = 3 + json_set_idxshift; idx<=stacktop; idx++) {
jbe@173 738 // push metatable of "current value" onto stack:
jbe@173 739 if (!lua_getmetatable(L, -1)) lua_pushnil(L);
jbe@173 740 // distinguish according to type of path key:
jbe@173 741 switch (lua_type(L, idx)) {
jbe@173 742 case LUA_TSTRING:
jbe@173 743 // if path key is a string,
jbe@173 744 // check if "current value" is a JSON object (or table without metatable):
jbe@173 745 if (
jbe@173 746 lua_rawequal(L, -1, json_set_objectmt_idx) ||
jbe@173 747 (lua_isnil(L, -1) && lua_type(L, -2) == LUA_TTABLE)
jbe@173 748 ) {
jbe@173 749 // if "current value" is acceptable,
jbe@173 750 // pop metatable and leave "current value" on top of stack:
jbe@173 751 lua_pop(L, 1);
jbe@173 752 } else {
jbe@173 753 // if "current value" is not acceptable:
jbe@173 754 // pop metatable and "current value":
jbe@173 755 lua_pop(L, 2);
jbe@173 756 // throw error if parent element does not exist:
jbe@173 757 if (lua_isnil(L, -1)) return luaL_error(L, "Root element is not a JSON object");
jbe@173 758 // push new JSON object as "current value" onto stack:
jbe@193 759 json_createproxy(L);
jbe@173 760 // create and register shadow table:
jbe@173 761 lua_newtable(L);
jbe@193 762 json_setshadow(L, -2);
jbe@173 763 // set metatable of JSON object:
jbe@173 764 lua_pushvalue(L, json_set_objectmt_idx);
jbe@173 765 lua_setmetatable(L, -2);
jbe@173 766 // set entry in "parent value":
jbe@173 767 lua_pushvalue(L, idx-1);
jbe@173 768 lua_pushvalue(L, -2);
jbe@173 769 lua_settable(L, -4);
jbe@173 770 }
jbe@173 771 break;
jbe@173 772 case LUA_TNUMBER:
jbe@173 773 // if path key is a number,
jbe@173 774 // check if "current value" is a JSON array (or table without metatable):
jbe@173 775 if (
jbe@173 776 lua_rawequal(L, -1, json_set_arraymt_idx) ||
jbe@173 777 (lua_isnil(L, -1) && lua_type(L, -2) == LUA_TTABLE)
jbe@173 778 ) {
jbe@173 779 // if "current value" is acceptable,
jbe@173 780 // pop metatable and leave "current value" on top of stack:
jbe@173 781 lua_pop(L, 1);
jbe@173 782 } else {
jbe@173 783 // if "current value" is not acceptable:
jbe@173 784 // pop metatable and "current value":
jbe@173 785 lua_pop(L, 2);
jbe@173 786 // throw error if parent element does not exist:
jbe@173 787 if (lua_isnil(L, -1)) return luaL_error(L, "Root element is not a JSON array");
jbe@173 788 // push new JSON array as "current value" onto stack:
jbe@193 789 json_createproxy(L);
jbe@173 790 // create and register shadow table:
jbe@173 791 lua_newtable(L);
jbe@193 792 json_setshadow(L, -2);
jbe@173 793 // set metatable of JSON array:
jbe@173 794 lua_pushvalue(L, json_set_arraymt_idx);
jbe@173 795 lua_setmetatable(L, -2);
jbe@173 796 // set entry in "parent value":
jbe@173 797 lua_pushvalue(L, idx-1);
jbe@173 798 lua_pushvalue(L, -2);
jbe@173 799 lua_settable(L, -4);
jbe@173 800 }
jbe@173 801 break;
jbe@173 802 default:
jbe@173 803 return luaL_error(L, "Invalid path key of type %s", lua_typename(L, lua_type(L, idx)));
jbe@173 804 }
jbe@173 805 // check if last path element is being processed:
jbe@173 806 if (idx == stacktop) {
jbe@173 807 // if the last path element is being processed,
jbe@173 808 // set last path value in "current value" container:
jbe@173 809 lua_pushvalue(L, idx);
jbe@173 810 lua_pushvalue(L, 2 + json_set_idxshift);
jbe@173 811 lua_settable(L, -3);
jbe@173 812 } else {
jbe@173 813 // if the processed path element is not the last,
jbe@173 814 // use old "current value" as new "parent value"
jbe@173 815 lua_remove(L, -2);
jbe@173 816 // push new "current value" onto stack by performing a lookup:
jbe@173 817 lua_pushvalue(L, idx);
jbe@173 818 lua_gettable(L, -2);
jbe@173 819 }
jbe@173 820 }
jbe@173 821 // return first argument for convenience:
jbe@173 822 lua_settop(L, 1 + json_set_idxshift);
jbe@173 823 return 1;
jbe@173 824 }
jbe@173 825
jbe@147 826 // returns the length of a JSON array (or zero for a table without numeric keys):
jbe@130 827 static int json_len(lua_State *L) {
jbe@147 828 // stack shall contain one function argument:
jbe@130 829 lua_settop(L, 1);
jbe@193 830 // push shadow table or nil onto stack:
jbe@193 831 json_getshadow(L, 1);
jbe@193 832 // pop nil from stack if no shadow table has been found:
jbe@193 833 if (lua_isnil(L, -1)) lua_pop(L, 1);
jbe@193 834 // return length of argument or shadow table:
jbe@193 835 lua_pushnumber(L, lua_rawlen(L, -1));
jbe@123 836 return 1;
jbe@123 837 }
jbe@123 838
jbe@175 839 // __index metamethod for JSON objects and JSON arrays:
jbe@130 840 static int json_index(lua_State *L) {
jbe@148 841 // stack shall contain two function arguments:
jbe@130 842 lua_settop(L, 2);
jbe@193 843 // replace first argument with its shadow table
jbe@193 844 // or throw error if no shadow table is found:
jbe@193 845 json_getshadow(L, 1);
jbe@139 846 if (lua_isnil(L, -1)) return luaL_error(L, "Shadow table not found");
jbe@193 847 lua_replace(L, 1);
jbe@148 848 // use key passed as second argument to lookup value in shadow table:
jbe@193 849 lua_rawget(L, 1);
jbe@148 850 // if value is null-marker, then push nil onto stack:
jbe@193 851 if (json_isnullmark(L, 2)) lua_pushnil(L);
jbe@148 852 // return either looked up value, or nil
jbe@127 853 return 1;
jbe@127 854 }
jbe@127 855
jbe@175 856 // __newindex metamethod for JSON objects and JSON arrays:
jbe@130 857 static int json_newindex(lua_State *L) {
jbe@148 858 // stack shall contain three function arguments:
jbe@130 859 lua_settop(L, 3);
jbe@193 860 // replace first argument with its shadow table
jbe@193 861 // or throw error if no shadow table is found:
jbe@193 862 json_getshadow(L, 1);
jbe@130 863 if (lua_isnil(L, -1)) return luaL_error(L, "Shadow table not found");
jbe@130 864 lua_replace(L, 1);
jbe@193 865 // second and third argument to write to shadow table:
jbe@130 866 lua_rawset(L, 1);
jbe@148 867 // return nothing:
jbe@148 868 return 0;
jbe@121 869 }
jbe@121 870
jbe@175 871 // function returned as first value by json_pairs function:
jbe@135 872 static int json_pairs_iterfunc(lua_State *L) {
jbe@149 873 // stack shall contain two function arguments:
jbe@135 874 lua_settop(L, 2);
jbe@193 875 // replace first argument with its shadow table
jbe@193 876 // or throw error if no shadow table is found:
jbe@193 877 json_getshadow(L, 1);
jbe@135 878 if (lua_isnil(L, -1)) return luaL_error(L, "Shadow table not found");
jbe@193 879 lua_replace(L, 1);
jbe@149 880 // get next key value pair from shadow table (using previous key from argument 2)
jbe@149 881 // and return nothing if there is no next pair:
jbe@193 882 if (!lua_next(L, 1)) return 0;
jbe@149 883 // replace null-marker with nil:
jbe@155 884 if (json_isnullmark(L, -1)) {
jbe@135 885 lua_pop(L, 1);
jbe@135 886 lua_pushnil(L);
jbe@135 887 }
jbe@149 888 // return key and value (or key and nil, if null-marker was found):
jbe@135 889 return 2;
jbe@135 890 }
jbe@135 891
jbe@149 892 // returns a triple such that 'for key, value in pairs(obj) do ... end'
jbe@175 893 // iterates through all key value pairs (including JSON null values represented as Lua nil):
jbe@135 894 static int json_pairs(lua_State *L) {
jbe@172 895 // require one argument to function
jbe@172 896 luaL_checkany(L, 1);
jbe@149 897 // return triple of function json_pairs_iterfunc, first argument, and nil:
jbe@139 898 lua_pushcfunction(L, json_pairs_iterfunc);
jbe@135 899 lua_pushvalue(L, 1);
jbe@135 900 lua_pushnil(L);
jbe@135 901 return 3;
jbe@135 902 }
jbe@135 903
jbe@175 904 // function returned as first value by json_ipairs function:
jbe@134 905 static int json_ipairs_iterfunc(lua_State *L) {
jbe@152 906 lua_Integer idx;
jbe@149 907 // stack shall contain two function arguments:
jbe@134 908 lua_settop(L, 2);
jbe@149 909 // calculate new index by incrementing second argument:
jbe@134 910 idx = lua_tointeger(L, 2) + 1;
jbe@193 911 // push shadow table onto stack position 3
jbe@193 912 // or throw error if no shadow table is found:
jbe@193 913 json_getshadow(L, 1);
jbe@134 914 if (lua_isnil(L, -1)) return luaL_error(L, "Shadow table not found");
jbe@193 915 // do integer lookup in shadow table and store result on stack position 4:
jbe@193 916 lua_rawgeti(L, 3, idx);
jbe@149 917 // return nothing if there was no value:
jbe@193 918 if (lua_isnil(L, 4)) return 0;
jbe@149 919 // return new index and
jbe@149 920 // either the looked up value if it is not equal to the null-marker
jbe@149 921 // or nil instead of null-marker:
jbe@134 922 lua_pushinteger(L, idx);
jbe@193 923 if (json_isnullmark(L, 4)) lua_pushnil(L);
jbe@193 924 else lua_pushvalue(L, 4);
jbe@134 925 return 2;
jbe@134 926 }
jbe@134 927
jbe@149 928 // returns a triple such that 'for idx, value in ipairs(ary) do ... end'
jbe@175 929 // iterates through all values (including JSON null values represented as Lua nil):
jbe@134 930 static int json_ipairs(lua_State *L) {
jbe@172 931 // require one argument to function
jbe@172 932 luaL_checkany(L, 1);
jbe@149 933 // return triple of function json_ipairs_iterfunc, first argument, and zero:
jbe@139 934 lua_pushcfunction(L, json_ipairs_iterfunc);
jbe@134 935 lua_pushvalue(L, 1);
jbe@134 936 lua_pushinteger(L, 0);
jbe@134 937 return 3;
jbe@134 938 }
jbe@134 939
jbe@175 940 // datatype representing a table key:
jbe@175 941 // (used for sorting)
jbe@163 942 typedef struct {
jbe@163 943 size_t length;
jbe@163 944 const char *data;
jbe@163 945 } json_key_t;
jbe@163 946
jbe@175 947 // comparation function for table keys to be passed to qsort function:
jbe@163 948 static int json_key_cmp(json_key_t *key1, json_key_t *key2) {
jbe@163 949 size_t pos = 0;
jbe@163 950 unsigned char c1, c2;
jbe@163 951 while (1) {
jbe@163 952 if (key1->length > pos) {
jbe@163 953 if (key2->length > pos) {
jbe@163 954 c1 = key1->data[pos];
jbe@163 955 c2 = key2->data[pos];
jbe@163 956 if (c1 < c2) return -1;
jbe@163 957 else if (c1 > c2) return 1;
jbe@163 958 } else {
jbe@163 959 return 1;
jbe@163 960 }
jbe@163 961 } else {
jbe@163 962 if (key2->length > pos) {
jbe@163 963 return -1;
jbe@163 964 } else {
jbe@163 965 return 0;
jbe@163 966 }
jbe@163 967 }
jbe@163 968 pos++;
jbe@163 969 }
jbe@163 970 }
jbe@163 971
jbe@175 972 // constants for type detection of ambiguous tables:
jbe@154 973 #define JSON_TABLETYPE_UNKNOWN 0
jbe@154 974 #define JSON_TABLETYPE_OBJECT 1
jbe@154 975 #define JSON_TABLETYPE_ARRAY 2
jbe@154 976
jbe@183 977 typedef struct {
jbe@183 978 int type;
jbe@183 979 int pos;
jbe@183 980 int count;
jbe@183 981 json_key_t keys[1]; // or more
jbe@183 982 } json_container_t;
jbe@183 983
jbe@183 984 // special Lua stack indicies for json_export function:
jbe@183 985 #define json_export_value_idx 1
jbe@183 986 #define json_export_indentstring_idx 2
jbe@183 987 #define json_export_objectmt_idx 3
jbe@183 988 #define json_export_arraymt_idx 4
jbe@193 989 #define json_export_stackswap_idx 5
jbe@193 990 #define json_export_luacontainer_idx 6
jbe@193 991 #define json_export_ccontainer_idx 7
jbe@193 992 #define json_export_buffer_idx 8
jbe@164 993
jbe@183 994 // encodes a JSON document (passed as first argument)
jbe@187 995 // optionally using indentation (indentation string or true passed as second argument)
jbe@183 996 static int json_export(lua_State *L) {
jbe@183 997 int pretty; // pretty printing on? (i.e. printing with indentation)
jbe@183 998 luaL_Buffer buf; // Lua buffer containing result string
jbe@183 999 lua_Number num; // number to encode
jbe@190 1000 char numstr[21]; // encoded number (sign, zero, point, 17 significant digits, and terminating NULL byte)
jbe@183 1001 const char *str; // string to encode
jbe@183 1002 size_t strlen; // length of string to encode
jbe@183 1003 size_t strpos ; // position in string or position of current key
jbe@183 1004 unsigned char c; // character to encode (unsigned!)
jbe@183 1005 char hexcode[7]; // store for unicode hex escape sequence
jbe@183 1006 // NOTE: 7 bytes due to backslash, character 'u', 4 hex digits, and terminating NULL byte
jbe@183 1007 int tabletype; // table type: unknown, JSON object, or JSON array
jbe@183 1008 size_t keycount = 0; // number of string keys in object
jbe@185 1009 json_key_t *key; // pointer to C structure containing a string key
jbe@183 1010 int level = 0; // current depth level
jbe@183 1011 int i; // iteration variable for level dependent repetitions
jbe@183 1012 int stackswapidx = 0; // elements in stack swap table
jbe@183 1013 int containerkey = 0; // temporarily set to 1, if a container key is being encoded
jbe@183 1014 json_container_t *container = NULL; // pointer to current C struct for container information
jbe@183 1015 // stack shall contain two function arguments:
jbe@183 1016 lua_settop(L, 2);
jbe@188 1017 // check if pretty printing (with indentation) is desired:
jbe@188 1018 if (lua_toboolean(L, json_export_indentstring_idx)) {
jbe@188 1019 // if yes,
jbe@188 1020 // set pretty variable to 1:
jbe@188 1021 pretty = 1;
jbe@188 1022 // check if second argument is a boolean (true):
jbe@188 1023 if (lua_isboolean(L, json_export_indentstring_idx)) {
jbe@188 1024 // if yes,
jbe@188 1025 // use default indentation if indentation argument is boolean true:
jbe@188 1026 lua_pushliteral(L, " ");
jbe@188 1027 lua_replace(L, json_export_indentstring_idx);
jbe@188 1028 } else {
jbe@188 1029 // if no,
jbe@188 1030 // require second argument to be a string:
jbe@188 1031 luaL_checktype(L, json_export_indentstring_idx, LUA_TSTRING);
jbe@188 1032 }
jbe@188 1033 } else {
jbe@188 1034 // if no,
jbe@188 1035 // set pretty variable to 0:
jbe@188 1036 pretty = 0;
jbe@157 1037 }
jbe@183 1038 // push objectmt onto stack position 3:
jbe@183 1039 json_regfetch(L, objectmt);
jbe@183 1040 // push arraymt onto stack position 4:
jbe@183 1041 json_regfetch(L, arraymt);
jbe@193 1042 // push table for stack swapping onto stack position 5:
jbe@183 1043 lua_newtable(L);
jbe@193 1044 // create placeholders on stack positions 6 through 7:
jbe@187 1045 lua_settop(L, json_export_buffer_idx);
jbe@183 1046 // create Lua string buffer:
jbe@183 1047 luaL_buffinit(L, &buf);
jbe@183 1048 // loop:
jbe@183 1049 while (1) {
jbe@183 1050 // if value to encode is the null-marker, then treat it the same as nil:
jbe@183 1051 if (json_isnullmark(L, json_export_value_idx)) {
jbe@183 1052 lua_pushnil(L);
jbe@183 1053 lua_replace(L, json_export_value_idx);
jbe@164 1054 }
jbe@183 1055 // distinguish between different Lua types:
jbe@183 1056 switch (lua_type(L, json_export_value_idx)) {
jbe@183 1057 // value to encode is nil:
jbe@183 1058 case LUA_TNIL:
jbe@183 1059 // add string "null" to output buffer:
jbe@183 1060 luaL_addstring(&buf, "null");
jbe@183 1061 break;
jbe@183 1062 // value to encode is of type number:
jbe@183 1063 case LUA_TNUMBER:
jbe@183 1064 // convert value to double precision number:
jbe@183 1065 num = lua_tonumber(L, json_export_value_idx);
jbe@183 1066 // throw error if number is not-a-number:
jbe@183 1067 if (isnan(num)) return luaL_error(L, "JSON export not possible for NaN value");
jbe@183 1068 // throw error if number is positive or negative infinity:
jbe@183 1069 if (isinf(num)) return luaL_error(L, "JSON export not possible for infinite numbers");
jbe@191 1070 // determine necessary precision to represent double precision floating point number:
jbe@192 1071 sprintf(numstr, "%.16g", num);
jbe@191 1072 if (strtod(numstr, NULL) != num) sprintf(numstr, "%.17g", num);
jbe@191 1073 // add string encoding of the number to the output buffer:
jbe@189 1074 luaL_addstring(&buf, numstr);
jbe@183 1075 break;
jbe@183 1076 // value to encode is of type boolean:
jbe@183 1077 case LUA_TBOOLEAN:
jbe@183 1078 // add string "true" or "false" according to boolean value:
jbe@183 1079 luaL_addstring(&buf, lua_toboolean(L, json_export_value_idx) ? "true" : "false");
jbe@183 1080 break;
jbe@183 1081 // value to encode is of type string:
jbe@183 1082 case LUA_TSTRING:
jbe@183 1083 // add quoted and escaped string to output buffer:
jbe@183 1084 str = lua_tolstring(L, json_export_value_idx, &strlen);
jbe@183 1085 luaL_addchar(&buf, '"');
jbe@183 1086 strpos = 0;
jbe@183 1087 while (strpos < strlen) {
jbe@183 1088 c = str[strpos++];
jbe@183 1089 if (c == '"') luaL_addstring(&buf, "\\\"");
jbe@183 1090 else if (c == '\\') luaL_addstring(&buf, "\\\\");
jbe@183 1091 else if (c == 127) luaL_addstring(&buf, "\\u007F");
jbe@183 1092 else if (c >= 32) luaL_addchar(&buf, c);
jbe@183 1093 else if (c == '\b') luaL_addstring(&buf, "\\b");
jbe@183 1094 else if (c == '\f') luaL_addstring(&buf, "\\f");
jbe@183 1095 else if (c == '\n') luaL_addstring(&buf, "\\n");
jbe@183 1096 else if (c == '\r') luaL_addstring(&buf, "\\r");
jbe@183 1097 else if (c == '\t') luaL_addstring(&buf, "\\t");
jbe@183 1098 else if (c == '\v') luaL_addstring(&buf, "\\v");
jbe@183 1099 else {
jbe@183 1100 sprintf(hexcode, "\\u%04X", c);
jbe@183 1101 luaL_addstring(&buf, hexcode);
jbe@154 1102 }
jbe@154 1103 }
jbe@183 1104 luaL_addchar(&buf, '"');
jbe@183 1105 break;
jbe@183 1106 // value to encode is of type table (this includes JSON objects and JSON arrays):
jbe@183 1107 case LUA_TTABLE:
jbe@183 1108 // use table's metatable to try to determine type of table:
jbe@183 1109 tabletype = JSON_TABLETYPE_UNKNOWN;
jbe@188 1110 if (lua_getmetatable(L, json_export_value_idx)) {
jbe@183 1111 if (lua_rawequal(L, -1, json_export_objectmt_idx)) {
jbe@183 1112 tabletype = JSON_TABLETYPE_OBJECT;
jbe@183 1113 } else {
jbe@183 1114 if (lua_rawequal(L, -1, json_export_arraymt_idx)) {
jbe@183 1115 tabletype = JSON_TABLETYPE_ARRAY;
jbe@183 1116 } else {
jbe@183 1117 return luaL_error(L, "JSON export not possible for tables with nonsupported metatable");
jbe@183 1118 }
jbe@183 1119 }
jbe@183 1120 // reset stack (pop metatable from stack):
jbe@183 1121 lua_pop(L, 1);
jbe@183 1122 }
jbe@193 1123 // replace table with its shadow table if existent:
jbe@193 1124 json_getshadow(L, json_export_value_idx);
jbe@183 1125 if (lua_isnil(L, -1)) lua_pop(L, 1);
jbe@193 1126 else lua_replace(L, json_export_value_idx);
jbe@187 1127 // check if type of table is still undetermined
jbe@187 1128 // and optionally calculate number of string keys (keycount)
jbe@187 1129 // or set keycount to zero:
jbe@186 1130 keycount = 0;
jbe@183 1131 if (tabletype == JSON_TABLETYPE_UNKNOWN) {
jbe@187 1132 // if type of table is undetermined,
jbe@187 1133 // iterate over all keys:
jbe@188 1134 for (lua_pushnil(L); lua_next(L, json_export_value_idx); lua_pop(L, 1)) {
jbe@183 1135 switch (lua_type(L, -2)) {
jbe@183 1136 case LUA_TSTRING:
jbe@183 1137 // for string keys,
jbe@183 1138 // increase keycount (may avoid another iteration):
jbe@183 1139 keycount++;
jbe@183 1140 // if type of table was unknown, then type of table is a JSON object now:
jbe@183 1141 if (tabletype == JSON_TABLETYPE_UNKNOWN) tabletype = JSON_TABLETYPE_OBJECT;
jbe@183 1142 // if type of table was a JSON array, then the type of table is ambiguous now
jbe@183 1143 // and an error is thrown:
jbe@183 1144 else if (tabletype == JSON_TABLETYPE_ARRAY) goto json_export_tabletype_error;
jbe@183 1145 break;
jbe@183 1146 case LUA_TNUMBER:
jbe@183 1147 // for numeric keys,
jbe@183 1148 // if type of table was unknown, then type of table is a JSON array now:
jbe@183 1149 if (tabletype == JSON_TABLETYPE_UNKNOWN) tabletype = JSON_TABLETYPE_ARRAY;
jbe@183 1150 // if type of table was a JSON object, then the type of table is ambiguous now
jbe@183 1151 // and an error is thrown:
jbe@183 1152 else if (tabletype == JSON_TABLETYPE_OBJECT) goto json_export_tabletype_error;
jbe@183 1153 break;
jbe@183 1154 }
jbe@164 1155 }
jbe@163 1156 }
jbe@183 1157 // raise error if too many nested levels:
jbe@183 1158 if (level >= JSON_MAXDEPTH) {
jbe@183 1159 return luaL_error(L, "More than %d nested JSON levels", JSON_MAXDEPTH);
jbe@163 1160 }
jbe@183 1161 // store previous container information (if existent) on stack swap
jbe@183 1162 // and increase level variable:
jbe@183 1163 if (level++) {
jbe@183 1164 lua_pushvalue(L, json_export_luacontainer_idx);
jbe@183 1165 lua_rawseti(L, json_export_stackswap_idx, ++stackswapidx);
jbe@183 1166 lua_pushvalue(L, json_export_ccontainer_idx);
jbe@183 1167 lua_rawseti(L, json_export_stackswap_idx, ++stackswapidx);
jbe@183 1168 }
jbe@188 1169 // use value as current container:
jbe@188 1170 lua_pushvalue(L, json_export_value_idx);
jbe@188 1171 lua_replace(L, json_export_luacontainer_idx);
jbe@183 1172 // distinguish between JSON objects and JSON arrays:
jbe@183 1173 switch (tabletype) {
jbe@183 1174 // JSON object:
jbe@183 1175 case JSON_TABLETYPE_OBJECT:
jbe@183 1176 // calculate count of string keys unless it has been calculated before:
jbe@183 1177 if (!keycount) {
jbe@183 1178 for (lua_pushnil(L); lua_next(L, json_export_luacontainer_idx); lua_pop(L, 1)) {
jbe@183 1179 if (lua_type(L, -2) == LUA_TSTRING) keycount++;
jbe@164 1180 }
jbe@164 1181 }
jbe@186 1182 // allocate memory for C structure containing string keys and container iteration state:
jbe@186 1183 container = lua_newuserdata(L, sizeof(json_container_t) + (keycount-1) * sizeof(json_key_t));
jbe@187 1184 // store reference to C structure on designated stack position:
jbe@186 1185 lua_replace(L, json_export_ccontainer_idx);
jbe@186 1186 // initialize C structure for container state:
jbe@186 1187 container->type = JSON_TABLETYPE_OBJECT;
jbe@186 1188 container->count = keycount;
jbe@186 1189 container->pos = 0;
jbe@187 1190 // check if object contains any keys:
jbe@183 1191 if (keycount) {
jbe@187 1192 // if yes,
jbe@187 1193 // copy all string keys to the C structure (and reset container->pos again):
jbe@183 1194 for (lua_pushnil(L); lua_next(L, json_export_luacontainer_idx); lua_pop(L, 1)) {
jbe@183 1195 if (lua_type(L, -2) == LUA_TSTRING) {
jbe@183 1196 json_key_t *key = &container->keys[container->pos++];
jbe@183 1197 key->data = lua_tolstring(L, -2, &key->length);
jbe@183 1198 }
jbe@183 1199 }
jbe@183 1200 container->pos = 0;
jbe@183 1201 // sort C array using quicksort:
jbe@183 1202 qsort(container->keys, keycount, sizeof(json_key_t), (void *)json_key_cmp);
jbe@154 1203 }
jbe@183 1204 // add opening bracket to output buffer:
jbe@183 1205 luaL_addchar(&buf, '{');
jbe@183 1206 break;
jbe@183 1207 // JSON array:
jbe@183 1208 case JSON_TABLETYPE_ARRAY:
jbe@187 1209 // allocate memory for C structure for container iteration state:
jbe@183 1210 container = lua_newuserdata(L, sizeof(json_container_t) - sizeof(json_key_t));
jbe@187 1211 // store reference to C structure on designated stack position:
jbe@183 1212 lua_replace(L, json_export_ccontainer_idx);
jbe@187 1213 // initialize C structure for container state:
jbe@183 1214 container->type = JSON_TABLETYPE_ARRAY;
jbe@183 1215 container->pos = 0;
jbe@183 1216 // add opening bracket to output buffer:
jbe@183 1217 luaL_addchar(&buf, '[');
jbe@183 1218 break;
jbe@183 1219 default:
jbe@183 1220 // throw error if table type is unknown:
jbe@183 1221 json_export_tabletype_error:
jbe@183 1222 return luaL_error(L, "JSON export not possible for ambiguous table (cannot decide whether it is an object or array)");
jbe@183 1223 }
jbe@183 1224 break;
jbe@183 1225 default:
jbe@183 1226 // all other datatypes are considered an error:
jbe@183 1227 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 1228 }
jbe@187 1229 // check if a container is being processed:
jbe@183 1230 if (container) {
jbe@187 1231 // if yes,
jbe@187 1232 // execute code for container iteration:
jbe@184 1233 json_export_container:
jbe@187 1234 // distinguish between JSON objects and JSON arrays:
jbe@183 1235 switch (container->type) {
jbe@187 1236 // JSON object:
jbe@183 1237 case JSON_TABLETYPE_OBJECT:
jbe@187 1238 // finish iteration if all string keys have been processed:
jbe@185 1239 if (container->pos == container->count) goto json_export_close;
jbe@187 1240 // push current string key on top of stack:
jbe@185 1241 key = &container->keys[container->pos];
jbe@185 1242 lua_pushlstring(L, key->data, key->length);
jbe@187 1243 // check if the key has already been exported:
jbe@185 1244 if (!containerkey) {
jbe@187 1245 // if no,
jbe@187 1246 // add a comma to the output buffer if necessary:
jbe@185 1247 if (container->pos) luaL_addchar(&buf, ',');
jbe@187 1248 // set containerkey variable to true:
jbe@185 1249 containerkey = 1;
jbe@183 1250 } else {
jbe@187 1251 // if a key has already been exported,
jbe@187 1252 // add a colon to the output buffer:
jbe@185 1253 luaL_addchar(&buf, ':');
jbe@187 1254 // add a space to the output buffer for pretty results:
jbe@185 1255 if (pretty) luaL_addchar(&buf, ' ');
jbe@187 1256 // replace string key on top of stack with corresponding value:
jbe@185 1257 lua_rawget(L, json_export_luacontainer_idx);
jbe@187 1258 // reset containerkey variable
jbe@185 1259 containerkey = 0;
jbe@187 1260 // increase number of processed key value pairs:
jbe@185 1261 container->pos++;
jbe@163 1262 }
jbe@187 1263 // store key or value on top of stack in designated stack position:
jbe@185 1264 lua_replace(L, json_export_value_idx);
jbe@183 1265 break;
jbe@187 1266 // JSON array:
jbe@183 1267 case JSON_TABLETYPE_ARRAY:
jbe@187 1268 // store next value in designated stack position:
jbe@185 1269 lua_rawgeti(L, json_export_luacontainer_idx, container->pos+1);
jbe@183 1270 lua_replace(L, json_export_value_idx);
jbe@187 1271 // finish iteration if value is nil:
jbe@185 1272 if (lua_isnil(L, json_export_value_idx)) goto json_export_close;
jbe@187 1273 // add a comma to the output buffer if necessary:
jbe@185 1274 if (container->pos) luaL_addchar(&buf, ',');
jbe@187 1275 // increase number of processed values:
jbe@185 1276 container->pos++;
jbe@183 1277 break;
jbe@187 1278 // common code for closing JSON objects or JSON arrays:
jbe@183 1279 json_export_close:
jbe@187 1280 // decrement level variable:
jbe@185 1281 level--;
jbe@187 1282 // handle indentation for pretty results:
jbe@187 1283 if (pretty && container->pos) {
jbe@187 1284 luaL_addchar(&buf, '\n');
jbe@187 1285 for (i=0; i<level; i++) {
jbe@187 1286 lua_pushvalue(L, json_export_indentstring_idx);
jbe@187 1287 luaL_addvalue(&buf);
jbe@185 1288 }
jbe@164 1289 }
jbe@187 1290 // add closing bracket to output buffer:
jbe@185 1291 luaL_addchar(&buf, container->type == JSON_TABLETYPE_OBJECT ? '}' : ']');
jbe@187 1292 // finish export if last level has been closed:
jbe@185 1293 if (!level) goto json_export_finish;
jbe@187 1294 // otherwise,
jbe@187 1295 // recall previous container information from stack swap
jbe@187 1296 // and set C pointer to corresponding C struct:
jbe@185 1297 lua_rawgeti(L, json_export_stackswap_idx, stackswapidx--);
jbe@185 1298 lua_replace(L, json_export_ccontainer_idx);
jbe@185 1299 container = lua_touserdata(L, json_export_ccontainer_idx);
jbe@185 1300 lua_rawgeti(L, json_export_stackswap_idx, stackswapidx--);
jbe@185 1301 lua_replace(L, json_export_luacontainer_idx);
jbe@187 1302 // repeat code for container iteration:
jbe@185 1303 goto json_export_container;
jbe@164 1304 }
jbe@184 1305 // handle indentation for pretty results:
jbe@185 1306 if (pretty && (containerkey || container->type == JSON_TABLETYPE_ARRAY)) {
jbe@185 1307 luaL_addchar(&buf, '\n');
jbe@185 1308 for (i=0; i<level; i++) {
jbe@185 1309 lua_pushvalue(L, json_export_indentstring_idx);
jbe@185 1310 luaL_addvalue(&buf);
jbe@164 1311 }
jbe@154 1312 }
jbe@183 1313 } else {
jbe@187 1314 // if no container is being processed,
jbe@187 1315 // finish export:
jbe@185 1316 json_export_finish:
jbe@185 1317 // for pretty results, add final newline character if outermost container is processed:
jbe@185 1318 if (pretty) luaL_addchar(&buf, '\n');
jbe@187 1319 // create and return Lua string from buffer contents
jbe@154 1320 luaL_pushresult(&buf);
jbe@154 1321 return 1;
jbe@154 1322 }
jbe@154 1323 }
jbe@164 1324 }
jbe@164 1325
jbe@149 1326 // functions in library module:
jbe@121 1327 static const struct luaL_Reg json_module_functions[] = {
jbe@133 1328 {"object", json_object},
jbe@173 1329 {"array", json_array},
jbe@121 1330 {"import", json_import},
jbe@154 1331 {"export", json_export},
jbe@173 1332 {"get", json_get},
jbe@173 1333 {"type", json_type},
jbe@173 1334 {"set", json_set},
jbe@121 1335 {NULL, NULL}
jbe@121 1336 };
jbe@121 1337
jbe@149 1338 // metamethods for JSON objects, JSON arrays, and unknown JSON collections (object or array):
jbe@126 1339 static const struct luaL_Reg json_metatable_functions[] = {
jbe@130 1340 {"__len", json_len},
jbe@130 1341 {"__index", json_index},
jbe@130 1342 {"__newindex", json_newindex},
jbe@135 1343 {"__pairs", json_pairs},
jbe@134 1344 {"__ipairs", json_ipairs},
jbe@160 1345 {"__tostring", json_export},
jbe@126 1346 {NULL, NULL}
jbe@126 1347 };
jbe@126 1348
jbe@157 1349 // metamethods for JSON null marker:
jbe@157 1350 static const struct luaL_Reg json_nullmark_metamethods[] = {
jbe@157 1351 {"__tostring", json_nullmark_tostring},
jbe@157 1352 {NULL, NULL}
jbe@157 1353 };
jbe@157 1354
jbe@149 1355 // initializes json library:
jbe@121 1356 int luaopen_json(lua_State *L) {
jbe@149 1357 // empty stack:
jbe@126 1358 lua_settop(L, 0);
jbe@149 1359 // push library module onto stack position 1:
jbe@149 1360 lua_newtable(L);
jbe@149 1361 // register library functions:
jbe@149 1362 luaL_setfuncs(L, json_module_functions, 0);
jbe@149 1363 // create and store objectmt:
jbe@138 1364 lua_newtable(L);
jbe@138 1365 luaL_setfuncs(L, json_metatable_functions, 0);
jbe@144 1366 json_regstore(L, objectmt);
jbe@149 1367 // create and store arraymt:
jbe@138 1368 lua_newtable(L);
jbe@138 1369 luaL_setfuncs(L, json_metatable_functions, 0);
jbe@144 1370 json_regstore(L, arraymt);
jbe@157 1371 // set metatable of null marker and make it available through library module:
jbe@157 1372 json_pushnullmark(L);
jbe@157 1373 lua_newtable(L);
jbe@157 1374 luaL_setfuncs(L, json_nullmark_metamethods, 0);
jbe@157 1375 lua_setmetatable(L, -2);
jbe@157 1376 lua_setfield(L, 1, "null");
jbe@157 1377 // return library module (that's expected on top of stack):
jbe@121 1378 return 1;
jbe@121 1379 }

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