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annotate libraries/json/json.c @ 194:654ddbcc49d0

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Bugfix in autodoc.lua; Added documentation for JSON library; json.import(...) returns json.null for "null" on top-level
author jbe
date Mon Aug 11 17:38:12 2014 +0200 (2014-08-11)
parents 0014a7c22013
children 9fd7e1bf9fe3
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@194 554 // push special null-marker onto stack:
jbe@194 555 json_pushnullmark(L);
jbe@121 556 } else {
jbe@136 557 // all other cases are a syntax error:
jbe@121 558 goto json_import_syntax_error;
jbe@121 559 }
jbe@136 560 // process a decoded value or key value pair (expected on top of Lua stack):
jbe@136 561 json_import_process_value:
jbe@121 562 switch (mode) {
jbe@136 563 // an object key has been read:
jbe@124 564 case JSON_STATE_OBJECT_KEY:
jbe@136 565 // if an object key is not a string, then this is a syntax error:
jbe@121 566 if (lua_type(L, -1) != LUA_TSTRING) goto json_import_syntax_error;
jbe@146 567 // expect key terminator to follow:
jbe@124 568 mode = JSON_STATE_OBJECT_KEY_TERMINATOR;
jbe@146 569 // continue with loop:
jbe@121 570 goto json_import_loop;
jbe@136 571 // a key value pair has been read:
jbe@124 572 case JSON_STATE_OBJECT_VALUE:
jbe@136 573 // store key value pair in outer shadow table:
jbe@130 574 lua_rawset(L, -3);
jbe@146 575 // expect value terminator (or end of object) to follow:
jbe@124 576 mode = JSON_STATE_OBJECT_SEPARATOR;
jbe@146 577 // continue with loop:
jbe@121 578 goto json_import_loop;
jbe@136 579 // an array value has been read:
jbe@124 580 case JSON_STATE_ARRAY_VALUE:
jbe@152 581 // get current array length:
jbe@152 582 arraylen = lua_rawlen(L, -3);
jbe@152 583 // throw error if array would exceed INT_MAX elements:
jbe@152 584 // TODO: Lua 5.3 may support more elements
jbe@152 585 if (arraylen >= INT_MAX) {
jbe@152 586 lua_pushnil(L);
jbe@152 587 lua_pushfstring(L, "Array exceeded length of %d elements", INT_MAX);
jbe@152 588 }
jbe@136 589 // store value in outer shadow table:
jbe@152 590 lua_rawseti(L, -3, arraylen + 1);
jbe@146 591 // expect value terminator (or end of object) to follow:
jbe@124 592 mode = JSON_STATE_ARRAY_SEPARATOR;
jbe@146 593 // continue with loop
jbe@121 594 goto json_import_loop;
jbe@136 595 // a single value has been read:
jbe@124 596 case JSON_STATE_VALUE:
jbe@136 597 // leave value on top of stack, expect end of JSON document, and continue with loop:
jbe@124 598 mode = JSON_STATE_END;
jbe@121 599 goto json_import_loop;
jbe@121 600 }
jbe@146 601 // syntax error handling (reachable by goto statement):
jbe@136 602 json_import_syntax_error:
jbe@121 603 lua_pushnil(L);
jbe@121 604 lua_pushliteral(L, "Syntax error in JSON document");
jbe@121 605 return 2;
jbe@121 606 }
jbe@121 607
jbe@146 608 // gets a value or its type from a JSON document (passed as first argument)
jbe@175 609 // using a path (passed as variable number of keys after the first argument):
jbe@137 610 static int json_path(lua_State *L, int type_mode) {
jbe@193 611 int stacktop; // number of arguments
jbe@193 612 int idx = 2; // stack index of current argument to process
jbe@173 613 // require at least one argument:
jbe@173 614 luaL_checkany(L, 1);
jbe@193 615 // store stack index of top of stack (number of arguments):
jbe@138 616 stacktop = lua_gettop(L);
jbe@146 617 // use first argument as "current value" (stored on top of stack):
jbe@193 618 lua_pushvalue(L, 1);
jbe@146 619 // process each "path key" (2nd argument and following arguments):
jbe@138 620 while (idx <= stacktop) {
jbe@146 621 // if "current value" (on top of stack) is nil, then the path cannot be walked and nil is returned:
jbe@137 622 if (lua_isnil(L, -1)) return 1;
jbe@137 623 // try to get shadow table of "current value":
jbe@193 624 json_getshadow(L, -1);
jbe@126 625 if (lua_isnil(L, -1)) {
jbe@137 626 // if no shadow table is found,
jbe@193 627 if (lua_type(L, -2) == LUA_TTABLE) {
jbe@146 628 // and if "current value" is a table,
jbe@193 629 // pop nil from stack:
jbe@146 630 lua_pop(L, 1);
jbe@137 631 // get "next value" using the "path key":
jbe@130 632 lua_pushvalue(L, idx++);
jbe@130 633 lua_gettable(L, -2);
jbe@130 634 } else {
jbe@137 635 // if "current value" is not a table,
jbe@146 636 // then the path cannot be walked and nil (already on top of stack) is returned:
jbe@137 637 return 1;
jbe@130 638 }
jbe@130 639 } else {
jbe@137 640 // if a shadow table is found,
jbe@137 641 // set "current value" to its shadow table:
jbe@130 642 lua_replace(L, -2);
jbe@137 643 // get "next value" using the "path key":
jbe@130 644 lua_pushvalue(L, idx++);
jbe@130 645 lua_rawget(L, -2);
jbe@126 646 }
jbe@137 647 // the "next value" replaces the "current value":
jbe@130 648 lua_replace(L, -2);
jbe@126 649 }
jbe@137 650 if (!type_mode) {
jbe@137 651 // if a value (and not its type) was requested,
jbe@137 652 // check if value is the null-marker, and store nil on top of Lua stack in that case:
jbe@155 653 if (json_isnullmark(L, -1)) lua_pushnil(L);
jbe@137 654 } else {
jbe@137 655 // if the type was requested,
jbe@137 656 // check if value is the null-marker:
jbe@155 657 if (json_isnullmark(L, -1)) {
jbe@137 658 // if yes, store string "null" on top of Lua stack:
jbe@130 659 lua_pushliteral(L, "null");
jbe@137 660 } else {
jbe@137 661 // otherwise,
jbe@138 662 // check if metatable indicates "object" or "array":
jbe@138 663 if (lua_getmetatable(L, -1)) {
jbe@144 664 json_regfetch(L, objectmt);
jbe@138 665 if (lua_rawequal(L, -2, -1)) {
jbe@146 666 // if value has metatable for JSON objects,
jbe@138 667 // return string "object":
jbe@138 668 lua_pushliteral(L, "object");
jbe@138 669 return 1;
jbe@138 670 }
jbe@144 671 json_regfetch(L, arraymt);
jbe@138 672 if (lua_rawequal(L, -3, -1)) {
jbe@146 673 // if value has metatable for JSON arrays,
jbe@146 674 // return string "object":
jbe@138 675 lua_pushliteral(L, "array");
jbe@138 676 return 1;
jbe@138 677 }
jbe@146 678 // remove 3 metatables (one of the value, two for comparison) from stack:
jbe@138 679 lua_pop(L, 3);
jbe@138 680 }
jbe@138 681 // otherwise, get the Lua type:
jbe@138 682 lua_pushstring(L, lua_typename(L, lua_type(L, -1)));
jbe@126 683 }
jbe@126 684 }
jbe@137 685 // return the top most value on the Lua stack:
jbe@137 686 return 1;
jbe@130 687 }
jbe@130 688
jbe@147 689 // gets a value from a JSON document (passed as first argument)
jbe@175 690 // using a path (passed as variable number of keys after the first argument):
jbe@130 691 static int json_get(lua_State *L) {
jbe@137 692 return json_path(L, 0);
jbe@130 693 }
jbe@130 694
jbe@147 695 // gets a value's type from a JSON document (passed as first argument)
jbe@175 696 // using a path (passed as variable number of keys after first the argument):
jbe@130 697 static int json_type(lua_State *L) {
jbe@137 698 return json_path(L, 1);
jbe@130 699 }
jbe@130 700
jbe@173 701 // special Lua stack indicies for json_set function:
jbe@193 702 #define json_set_objectmt_idx 1
jbe@193 703 #define json_set_arraymt_idx 2
jbe@173 704
jbe@173 705 // stack offset of arguments to json_set function:
jbe@193 706 #define json_set_idxshift 2
jbe@173 707
jbe@173 708 // sets a value (passed as second argument) in a JSON document (passed as first argument)
jbe@175 709 // using a path (passed as variable number of keys starting at third argument):
jbe@173 710 static int json_set(lua_State *L) {
jbe@193 711 int stacktop; // stack index of top of stack (after shifting)
jbe@193 712 int idx; // stack index of current argument to process
jbe@173 713 // require at least two arguments:
jbe@173 714 luaL_checkany(L, 1);
jbe@173 715 luaL_checkany(L, 2);
jbe@193 716 // insert objectmt into stack at position 1 (shifting the arguments):
jbe@173 717 json_regfetch(L, objectmt);
jbe@193 718 lua_insert(L, 1);
jbe@193 719 // insert arraymt into stack at position 2 (shifting the arguments):
jbe@193 720 json_regfetch(L, arraymt);
jbe@173 721 lua_insert(L, 2);
jbe@173 722 // store stack index of top of stack:
jbe@173 723 stacktop = lua_gettop(L);
jbe@173 724 // use nil as initial "parent value":
jbe@173 725 lua_pushnil(L);
jbe@173 726 // use first argument as "current value":
jbe@173 727 lua_pushvalue(L, 1 + json_set_idxshift);
jbe@173 728 // set all necessary values in path:
jbe@173 729 for (idx = 3 + json_set_idxshift; idx<=stacktop; idx++) {
jbe@173 730 // push metatable of "current value" onto stack:
jbe@173 731 if (!lua_getmetatable(L, -1)) lua_pushnil(L);
jbe@173 732 // distinguish according to type of path key:
jbe@173 733 switch (lua_type(L, idx)) {
jbe@173 734 case LUA_TSTRING:
jbe@173 735 // if path key is a string,
jbe@173 736 // check if "current value" is a JSON object (or table without metatable):
jbe@173 737 if (
jbe@173 738 lua_rawequal(L, -1, json_set_objectmt_idx) ||
jbe@173 739 (lua_isnil(L, -1) && lua_type(L, -2) == LUA_TTABLE)
jbe@173 740 ) {
jbe@173 741 // if "current value" is acceptable,
jbe@173 742 // pop metatable and leave "current value" on top of stack:
jbe@173 743 lua_pop(L, 1);
jbe@173 744 } else {
jbe@173 745 // if "current value" is not acceptable:
jbe@173 746 // pop metatable and "current value":
jbe@173 747 lua_pop(L, 2);
jbe@173 748 // throw error if parent element does not exist:
jbe@173 749 if (lua_isnil(L, -1)) return luaL_error(L, "Root element is not a JSON object");
jbe@173 750 // push new JSON object as "current value" onto stack:
jbe@193 751 json_createproxy(L);
jbe@173 752 // create and register shadow table:
jbe@173 753 lua_newtable(L);
jbe@193 754 json_setshadow(L, -2);
jbe@173 755 // set metatable of JSON object:
jbe@173 756 lua_pushvalue(L, json_set_objectmt_idx);
jbe@173 757 lua_setmetatable(L, -2);
jbe@173 758 // set entry in "parent value":
jbe@173 759 lua_pushvalue(L, idx-1);
jbe@173 760 lua_pushvalue(L, -2);
jbe@173 761 lua_settable(L, -4);
jbe@173 762 }
jbe@173 763 break;
jbe@173 764 case LUA_TNUMBER:
jbe@173 765 // if path key is a number,
jbe@173 766 // check if "current value" is a JSON array (or table without metatable):
jbe@173 767 if (
jbe@173 768 lua_rawequal(L, -1, json_set_arraymt_idx) ||
jbe@173 769 (lua_isnil(L, -1) && lua_type(L, -2) == LUA_TTABLE)
jbe@173 770 ) {
jbe@173 771 // if "current value" is acceptable,
jbe@173 772 // pop metatable and leave "current value" on top of stack:
jbe@173 773 lua_pop(L, 1);
jbe@173 774 } else {
jbe@173 775 // if "current value" is not acceptable:
jbe@173 776 // pop metatable and "current value":
jbe@173 777 lua_pop(L, 2);
jbe@173 778 // throw error if parent element does not exist:
jbe@173 779 if (lua_isnil(L, -1)) return luaL_error(L, "Root element is not a JSON array");
jbe@173 780 // push new JSON array as "current value" onto stack:
jbe@193 781 json_createproxy(L);
jbe@173 782 // create and register shadow table:
jbe@173 783 lua_newtable(L);
jbe@193 784 json_setshadow(L, -2);
jbe@173 785 // set metatable of JSON array:
jbe@173 786 lua_pushvalue(L, json_set_arraymt_idx);
jbe@173 787 lua_setmetatable(L, -2);
jbe@173 788 // set entry in "parent value":
jbe@173 789 lua_pushvalue(L, idx-1);
jbe@173 790 lua_pushvalue(L, -2);
jbe@173 791 lua_settable(L, -4);
jbe@173 792 }
jbe@173 793 break;
jbe@173 794 default:
jbe@173 795 return luaL_error(L, "Invalid path key of type %s", lua_typename(L, lua_type(L, idx)));
jbe@173 796 }
jbe@173 797 // check if last path element is being processed:
jbe@173 798 if (idx == stacktop) {
jbe@173 799 // if the last path element is being processed,
jbe@173 800 // set last path value in "current value" container:
jbe@173 801 lua_pushvalue(L, idx);
jbe@173 802 lua_pushvalue(L, 2 + json_set_idxshift);
jbe@173 803 lua_settable(L, -3);
jbe@173 804 } else {
jbe@173 805 // if the processed path element is not the last,
jbe@173 806 // use old "current value" as new "parent value"
jbe@173 807 lua_remove(L, -2);
jbe@173 808 // push new "current value" onto stack by performing a lookup:
jbe@173 809 lua_pushvalue(L, idx);
jbe@173 810 lua_gettable(L, -2);
jbe@173 811 }
jbe@173 812 }
jbe@173 813 // return first argument for convenience:
jbe@173 814 lua_settop(L, 1 + json_set_idxshift);
jbe@173 815 return 1;
jbe@173 816 }
jbe@173 817
jbe@147 818 // returns the length of a JSON array (or zero for a table without numeric keys):
jbe@130 819 static int json_len(lua_State *L) {
jbe@147 820 // stack shall contain one function argument:
jbe@130 821 lua_settop(L, 1);
jbe@193 822 // push shadow table or nil onto stack:
jbe@193 823 json_getshadow(L, 1);
jbe@193 824 // pop nil from stack if no shadow table has been found:
jbe@193 825 if (lua_isnil(L, -1)) lua_pop(L, 1);
jbe@193 826 // return length of argument or shadow table:
jbe@193 827 lua_pushnumber(L, lua_rawlen(L, -1));
jbe@123 828 return 1;
jbe@123 829 }
jbe@123 830
jbe@175 831 // __index metamethod for JSON objects and JSON arrays:
jbe@130 832 static int json_index(lua_State *L) {
jbe@148 833 // stack shall contain two function arguments:
jbe@130 834 lua_settop(L, 2);
jbe@193 835 // replace first argument with its shadow table
jbe@193 836 // or throw error if no shadow table is found:
jbe@193 837 json_getshadow(L, 1);
jbe@139 838 if (lua_isnil(L, -1)) return luaL_error(L, "Shadow table not found");
jbe@193 839 lua_replace(L, 1);
jbe@148 840 // use key passed as second argument to lookup value in shadow table:
jbe@193 841 lua_rawget(L, 1);
jbe@148 842 // if value is null-marker, then push nil onto stack:
jbe@193 843 if (json_isnullmark(L, 2)) lua_pushnil(L);
jbe@148 844 // return either looked up value, or nil
jbe@127 845 return 1;
jbe@127 846 }
jbe@127 847
jbe@175 848 // __newindex metamethod for JSON objects and JSON arrays:
jbe@130 849 static int json_newindex(lua_State *L) {
jbe@148 850 // stack shall contain three function arguments:
jbe@130 851 lua_settop(L, 3);
jbe@193 852 // replace first argument with its shadow table
jbe@193 853 // or throw error if no shadow table is found:
jbe@193 854 json_getshadow(L, 1);
jbe@130 855 if (lua_isnil(L, -1)) return luaL_error(L, "Shadow table not found");
jbe@130 856 lua_replace(L, 1);
jbe@193 857 // second and third argument to write to shadow table:
jbe@130 858 lua_rawset(L, 1);
jbe@148 859 // return nothing:
jbe@148 860 return 0;
jbe@121 861 }
jbe@121 862
jbe@175 863 // function returned as first value by json_pairs function:
jbe@135 864 static int json_pairs_iterfunc(lua_State *L) {
jbe@149 865 // stack shall contain two function arguments:
jbe@135 866 lua_settop(L, 2);
jbe@193 867 // replace first argument with its shadow table
jbe@193 868 // or throw error if no shadow table is found:
jbe@193 869 json_getshadow(L, 1);
jbe@135 870 if (lua_isnil(L, -1)) return luaL_error(L, "Shadow table not found");
jbe@193 871 lua_replace(L, 1);
jbe@149 872 // get next key value pair from shadow table (using previous key from argument 2)
jbe@149 873 // and return nothing if there is no next pair:
jbe@193 874 if (!lua_next(L, 1)) return 0;
jbe@149 875 // replace null-marker with nil:
jbe@155 876 if (json_isnullmark(L, -1)) {
jbe@135 877 lua_pop(L, 1);
jbe@135 878 lua_pushnil(L);
jbe@135 879 }
jbe@149 880 // return key and value (or key and nil, if null-marker was found):
jbe@135 881 return 2;
jbe@135 882 }
jbe@135 883
jbe@149 884 // returns a triple such that 'for key, value in pairs(obj) do ... end'
jbe@175 885 // iterates through all key value pairs (including JSON null values represented as Lua nil):
jbe@135 886 static int json_pairs(lua_State *L) {
jbe@172 887 // require one argument to function
jbe@172 888 luaL_checkany(L, 1);
jbe@149 889 // return triple of function json_pairs_iterfunc, first argument, and nil:
jbe@139 890 lua_pushcfunction(L, json_pairs_iterfunc);
jbe@135 891 lua_pushvalue(L, 1);
jbe@135 892 lua_pushnil(L);
jbe@135 893 return 3;
jbe@135 894 }
jbe@135 895
jbe@175 896 // function returned as first value by json_ipairs function:
jbe@134 897 static int json_ipairs_iterfunc(lua_State *L) {
jbe@152 898 lua_Integer idx;
jbe@149 899 // stack shall contain two function arguments:
jbe@134 900 lua_settop(L, 2);
jbe@149 901 // calculate new index by incrementing second argument:
jbe@134 902 idx = lua_tointeger(L, 2) + 1;
jbe@193 903 // push shadow table onto stack position 3
jbe@193 904 // or throw error if no shadow table is found:
jbe@193 905 json_getshadow(L, 1);
jbe@134 906 if (lua_isnil(L, -1)) return luaL_error(L, "Shadow table not found");
jbe@193 907 // do integer lookup in shadow table and store result on stack position 4:
jbe@193 908 lua_rawgeti(L, 3, idx);
jbe@149 909 // return nothing if there was no value:
jbe@193 910 if (lua_isnil(L, 4)) return 0;
jbe@149 911 // return new index and
jbe@149 912 // either the looked up value if it is not equal to the null-marker
jbe@149 913 // or nil instead of null-marker:
jbe@134 914 lua_pushinteger(L, idx);
jbe@193 915 if (json_isnullmark(L, 4)) lua_pushnil(L);
jbe@193 916 else lua_pushvalue(L, 4);
jbe@134 917 return 2;
jbe@134 918 }
jbe@134 919
jbe@149 920 // returns a triple such that 'for idx, value in ipairs(ary) do ... end'
jbe@175 921 // iterates through all values (including JSON null values represented as Lua nil):
jbe@134 922 static int json_ipairs(lua_State *L) {
jbe@172 923 // require one argument to function
jbe@172 924 luaL_checkany(L, 1);
jbe@149 925 // return triple of function json_ipairs_iterfunc, first argument, and zero:
jbe@139 926 lua_pushcfunction(L, json_ipairs_iterfunc);
jbe@134 927 lua_pushvalue(L, 1);
jbe@134 928 lua_pushinteger(L, 0);
jbe@134 929 return 3;
jbe@134 930 }
jbe@134 931
jbe@175 932 // datatype representing a table key:
jbe@175 933 // (used for sorting)
jbe@163 934 typedef struct {
jbe@163 935 size_t length;
jbe@163 936 const char *data;
jbe@163 937 } json_key_t;
jbe@163 938
jbe@175 939 // comparation function for table keys to be passed to qsort function:
jbe@163 940 static int json_key_cmp(json_key_t *key1, json_key_t *key2) {
jbe@163 941 size_t pos = 0;
jbe@163 942 unsigned char c1, c2;
jbe@163 943 while (1) {
jbe@163 944 if (key1->length > pos) {
jbe@163 945 if (key2->length > pos) {
jbe@163 946 c1 = key1->data[pos];
jbe@163 947 c2 = key2->data[pos];
jbe@163 948 if (c1 < c2) return -1;
jbe@163 949 else if (c1 > c2) return 1;
jbe@163 950 } else {
jbe@163 951 return 1;
jbe@163 952 }
jbe@163 953 } else {
jbe@163 954 if (key2->length > pos) {
jbe@163 955 return -1;
jbe@163 956 } else {
jbe@163 957 return 0;
jbe@163 958 }
jbe@163 959 }
jbe@163 960 pos++;
jbe@163 961 }
jbe@163 962 }
jbe@163 963
jbe@175 964 // constants for type detection of ambiguous tables:
jbe@154 965 #define JSON_TABLETYPE_UNKNOWN 0
jbe@154 966 #define JSON_TABLETYPE_OBJECT 1
jbe@154 967 #define JSON_TABLETYPE_ARRAY 2
jbe@154 968
jbe@183 969 typedef struct {
jbe@183 970 int type;
jbe@183 971 int pos;
jbe@183 972 int count;
jbe@183 973 json_key_t keys[1]; // or more
jbe@183 974 } json_container_t;
jbe@183 975
jbe@183 976 // special Lua stack indicies for json_export function:
jbe@183 977 #define json_export_value_idx 1
jbe@183 978 #define json_export_indentstring_idx 2
jbe@183 979 #define json_export_objectmt_idx 3
jbe@183 980 #define json_export_arraymt_idx 4
jbe@193 981 #define json_export_stackswap_idx 5
jbe@193 982 #define json_export_luacontainer_idx 6
jbe@193 983 #define json_export_ccontainer_idx 7
jbe@193 984 #define json_export_buffer_idx 8
jbe@164 985
jbe@183 986 // encodes a JSON document (passed as first argument)
jbe@187 987 // optionally using indentation (indentation string or true passed as second argument)
jbe@183 988 static int json_export(lua_State *L) {
jbe@183 989 int pretty; // pretty printing on? (i.e. printing with indentation)
jbe@183 990 luaL_Buffer buf; // Lua buffer containing result string
jbe@183 991 lua_Number num; // number to encode
jbe@190 992 char numstr[21]; // encoded number (sign, zero, point, 17 significant digits, and terminating NULL byte)
jbe@183 993 const char *str; // string to encode
jbe@183 994 size_t strlen; // length of string to encode
jbe@183 995 size_t strpos ; // position in string or position of current key
jbe@183 996 unsigned char c; // character to encode (unsigned!)
jbe@183 997 char hexcode[7]; // store for unicode hex escape sequence
jbe@183 998 // NOTE: 7 bytes due to backslash, character 'u', 4 hex digits, and terminating NULL byte
jbe@183 999 int tabletype; // table type: unknown, JSON object, or JSON array
jbe@183 1000 size_t keycount = 0; // number of string keys in object
jbe@185 1001 json_key_t *key; // pointer to C structure containing a string key
jbe@183 1002 int level = 0; // current depth level
jbe@183 1003 int i; // iteration variable for level dependent repetitions
jbe@183 1004 int stackswapidx = 0; // elements in stack swap table
jbe@183 1005 int containerkey = 0; // temporarily set to 1, if a container key is being encoded
jbe@183 1006 json_container_t *container = NULL; // pointer to current C struct for container information
jbe@183 1007 // stack shall contain two function arguments:
jbe@183 1008 lua_settop(L, 2);
jbe@188 1009 // check if pretty printing (with indentation) is desired:
jbe@188 1010 if (lua_toboolean(L, json_export_indentstring_idx)) {
jbe@188 1011 // if yes,
jbe@188 1012 // set pretty variable to 1:
jbe@188 1013 pretty = 1;
jbe@188 1014 // check if second argument is a boolean (true):
jbe@188 1015 if (lua_isboolean(L, json_export_indentstring_idx)) {
jbe@188 1016 // if yes,
jbe@188 1017 // use default indentation if indentation argument is boolean true:
jbe@188 1018 lua_pushliteral(L, " ");
jbe@188 1019 lua_replace(L, json_export_indentstring_idx);
jbe@188 1020 } else {
jbe@188 1021 // if no,
jbe@188 1022 // require second argument to be a string:
jbe@188 1023 luaL_checktype(L, json_export_indentstring_idx, LUA_TSTRING);
jbe@188 1024 }
jbe@188 1025 } else {
jbe@188 1026 // if no,
jbe@188 1027 // set pretty variable to 0:
jbe@188 1028 pretty = 0;
jbe@157 1029 }
jbe@183 1030 // push objectmt onto stack position 3:
jbe@183 1031 json_regfetch(L, objectmt);
jbe@183 1032 // push arraymt onto stack position 4:
jbe@183 1033 json_regfetch(L, arraymt);
jbe@193 1034 // push table for stack swapping onto stack position 5:
jbe@183 1035 lua_newtable(L);
jbe@193 1036 // create placeholders on stack positions 6 through 7:
jbe@187 1037 lua_settop(L, json_export_buffer_idx);
jbe@183 1038 // create Lua string buffer:
jbe@183 1039 luaL_buffinit(L, &buf);
jbe@183 1040 // loop:
jbe@183 1041 while (1) {
jbe@183 1042 // if value to encode is the null-marker, then treat it the same as nil:
jbe@183 1043 if (json_isnullmark(L, json_export_value_idx)) {
jbe@183 1044 lua_pushnil(L);
jbe@183 1045 lua_replace(L, json_export_value_idx);
jbe@164 1046 }
jbe@183 1047 // distinguish between different Lua types:
jbe@183 1048 switch (lua_type(L, json_export_value_idx)) {
jbe@183 1049 // value to encode is nil:
jbe@183 1050 case LUA_TNIL:
jbe@183 1051 // add string "null" to output buffer:
jbe@183 1052 luaL_addstring(&buf, "null");
jbe@183 1053 break;
jbe@183 1054 // value to encode is of type number:
jbe@183 1055 case LUA_TNUMBER:
jbe@183 1056 // convert value to double precision number:
jbe@183 1057 num = lua_tonumber(L, json_export_value_idx);
jbe@183 1058 // throw error if number is not-a-number:
jbe@183 1059 if (isnan(num)) return luaL_error(L, "JSON export not possible for NaN value");
jbe@183 1060 // throw error if number is positive or negative infinity:
jbe@183 1061 if (isinf(num)) return luaL_error(L, "JSON export not possible for infinite numbers");
jbe@191 1062 // determine necessary precision to represent double precision floating point number:
jbe@192 1063 sprintf(numstr, "%.16g", num);
jbe@191 1064 if (strtod(numstr, NULL) != num) sprintf(numstr, "%.17g", num);
jbe@191 1065 // add string encoding of the number to the output buffer:
jbe@189 1066 luaL_addstring(&buf, numstr);
jbe@183 1067 break;
jbe@183 1068 // value to encode is of type boolean:
jbe@183 1069 case LUA_TBOOLEAN:
jbe@183 1070 // add string "true" or "false" according to boolean value:
jbe@183 1071 luaL_addstring(&buf, lua_toboolean(L, json_export_value_idx) ? "true" : "false");
jbe@183 1072 break;
jbe@183 1073 // value to encode is of type string:
jbe@183 1074 case LUA_TSTRING:
jbe@183 1075 // add quoted and escaped string to output buffer:
jbe@183 1076 str = lua_tolstring(L, json_export_value_idx, &strlen);
jbe@183 1077 luaL_addchar(&buf, '"');
jbe@183 1078 strpos = 0;
jbe@183 1079 while (strpos < strlen) {
jbe@183 1080 c = str[strpos++];
jbe@183 1081 if (c == '"') luaL_addstring(&buf, "\\\"");
jbe@183 1082 else if (c == '\\') luaL_addstring(&buf, "\\\\");
jbe@183 1083 else if (c == 127) luaL_addstring(&buf, "\\u007F");
jbe@183 1084 else if (c >= 32) luaL_addchar(&buf, c);
jbe@183 1085 else if (c == '\b') luaL_addstring(&buf, "\\b");
jbe@183 1086 else if (c == '\f') luaL_addstring(&buf, "\\f");
jbe@183 1087 else if (c == '\n') luaL_addstring(&buf, "\\n");
jbe@183 1088 else if (c == '\r') luaL_addstring(&buf, "\\r");
jbe@183 1089 else if (c == '\t') luaL_addstring(&buf, "\\t");
jbe@183 1090 else if (c == '\v') luaL_addstring(&buf, "\\v");
jbe@183 1091 else {
jbe@183 1092 sprintf(hexcode, "\\u%04X", c);
jbe@183 1093 luaL_addstring(&buf, hexcode);
jbe@154 1094 }
jbe@154 1095 }
jbe@183 1096 luaL_addchar(&buf, '"');
jbe@183 1097 break;
jbe@183 1098 // value to encode is of type table (this includes JSON objects and JSON arrays):
jbe@183 1099 case LUA_TTABLE:
jbe@183 1100 // use table's metatable to try to determine type of table:
jbe@183 1101 tabletype = JSON_TABLETYPE_UNKNOWN;
jbe@188 1102 if (lua_getmetatable(L, json_export_value_idx)) {
jbe@183 1103 if (lua_rawequal(L, -1, json_export_objectmt_idx)) {
jbe@183 1104 tabletype = JSON_TABLETYPE_OBJECT;
jbe@183 1105 } else {
jbe@183 1106 if (lua_rawequal(L, -1, json_export_arraymt_idx)) {
jbe@183 1107 tabletype = JSON_TABLETYPE_ARRAY;
jbe@183 1108 } else {
jbe@183 1109 return luaL_error(L, "JSON export not possible for tables with nonsupported metatable");
jbe@183 1110 }
jbe@183 1111 }
jbe@183 1112 // reset stack (pop metatable from stack):
jbe@183 1113 lua_pop(L, 1);
jbe@183 1114 }
jbe@193 1115 // replace table with its shadow table if existent:
jbe@193 1116 json_getshadow(L, json_export_value_idx);
jbe@183 1117 if (lua_isnil(L, -1)) lua_pop(L, 1);
jbe@193 1118 else lua_replace(L, json_export_value_idx);
jbe@187 1119 // check if type of table is still undetermined
jbe@187 1120 // and optionally calculate number of string keys (keycount)
jbe@187 1121 // or set keycount to zero:
jbe@186 1122 keycount = 0;
jbe@183 1123 if (tabletype == JSON_TABLETYPE_UNKNOWN) {
jbe@187 1124 // if type of table is undetermined,
jbe@187 1125 // iterate over all keys:
jbe@188 1126 for (lua_pushnil(L); lua_next(L, json_export_value_idx); lua_pop(L, 1)) {
jbe@183 1127 switch (lua_type(L, -2)) {
jbe@183 1128 case LUA_TSTRING:
jbe@183 1129 // for string keys,
jbe@183 1130 // increase keycount (may avoid another iteration):
jbe@183 1131 keycount++;
jbe@183 1132 // if type of table was unknown, then type of table is a JSON object now:
jbe@183 1133 if (tabletype == JSON_TABLETYPE_UNKNOWN) tabletype = JSON_TABLETYPE_OBJECT;
jbe@183 1134 // if type of table was a JSON array, then the type of table is ambiguous now
jbe@183 1135 // and an error is thrown:
jbe@183 1136 else if (tabletype == JSON_TABLETYPE_ARRAY) goto json_export_tabletype_error;
jbe@183 1137 break;
jbe@183 1138 case LUA_TNUMBER:
jbe@183 1139 // for numeric keys,
jbe@183 1140 // if type of table was unknown, then type of table is a JSON array now:
jbe@183 1141 if (tabletype == JSON_TABLETYPE_UNKNOWN) tabletype = JSON_TABLETYPE_ARRAY;
jbe@183 1142 // if type of table was a JSON object, then the type of table is ambiguous now
jbe@183 1143 // and an error is thrown:
jbe@183 1144 else if (tabletype == JSON_TABLETYPE_OBJECT) goto json_export_tabletype_error;
jbe@183 1145 break;
jbe@183 1146 }
jbe@164 1147 }
jbe@163 1148 }
jbe@183 1149 // raise error if too many nested levels:
jbe@183 1150 if (level >= JSON_MAXDEPTH) {
jbe@183 1151 return luaL_error(L, "More than %d nested JSON levels", JSON_MAXDEPTH);
jbe@163 1152 }
jbe@183 1153 // store previous container information (if existent) on stack swap
jbe@183 1154 // and increase level variable:
jbe@183 1155 if (level++) {
jbe@183 1156 lua_pushvalue(L, json_export_luacontainer_idx);
jbe@183 1157 lua_rawseti(L, json_export_stackswap_idx, ++stackswapidx);
jbe@183 1158 lua_pushvalue(L, json_export_ccontainer_idx);
jbe@183 1159 lua_rawseti(L, json_export_stackswap_idx, ++stackswapidx);
jbe@183 1160 }
jbe@188 1161 // use value as current container:
jbe@188 1162 lua_pushvalue(L, json_export_value_idx);
jbe@188 1163 lua_replace(L, json_export_luacontainer_idx);
jbe@183 1164 // distinguish between JSON objects and JSON arrays:
jbe@183 1165 switch (tabletype) {
jbe@183 1166 // JSON object:
jbe@183 1167 case JSON_TABLETYPE_OBJECT:
jbe@183 1168 // calculate count of string keys unless it has been calculated before:
jbe@183 1169 if (!keycount) {
jbe@183 1170 for (lua_pushnil(L); lua_next(L, json_export_luacontainer_idx); lua_pop(L, 1)) {
jbe@183 1171 if (lua_type(L, -2) == LUA_TSTRING) keycount++;
jbe@164 1172 }
jbe@164 1173 }
jbe@186 1174 // allocate memory for C structure containing string keys and container iteration state:
jbe@186 1175 container = lua_newuserdata(L, sizeof(json_container_t) + (keycount-1) * sizeof(json_key_t));
jbe@187 1176 // store reference to C structure on designated stack position:
jbe@186 1177 lua_replace(L, json_export_ccontainer_idx);
jbe@186 1178 // initialize C structure for container state:
jbe@186 1179 container->type = JSON_TABLETYPE_OBJECT;
jbe@186 1180 container->count = keycount;
jbe@186 1181 container->pos = 0;
jbe@187 1182 // check if object contains any keys:
jbe@183 1183 if (keycount) {
jbe@187 1184 // if yes,
jbe@187 1185 // copy all string keys to the C structure (and reset container->pos again):
jbe@183 1186 for (lua_pushnil(L); lua_next(L, json_export_luacontainer_idx); lua_pop(L, 1)) {
jbe@183 1187 if (lua_type(L, -2) == LUA_TSTRING) {
jbe@183 1188 json_key_t *key = &container->keys[container->pos++];
jbe@183 1189 key->data = lua_tolstring(L, -2, &key->length);
jbe@183 1190 }
jbe@183 1191 }
jbe@183 1192 container->pos = 0;
jbe@183 1193 // sort C array using quicksort:
jbe@183 1194 qsort(container->keys, keycount, sizeof(json_key_t), (void *)json_key_cmp);
jbe@154 1195 }
jbe@183 1196 // add opening bracket to output buffer:
jbe@183 1197 luaL_addchar(&buf, '{');
jbe@183 1198 break;
jbe@183 1199 // JSON array:
jbe@183 1200 case JSON_TABLETYPE_ARRAY:
jbe@187 1201 // allocate memory for C structure for container iteration state:
jbe@183 1202 container = lua_newuserdata(L, sizeof(json_container_t) - sizeof(json_key_t));
jbe@187 1203 // store reference to C structure on designated stack position:
jbe@183 1204 lua_replace(L, json_export_ccontainer_idx);
jbe@187 1205 // initialize C structure for container state:
jbe@183 1206 container->type = JSON_TABLETYPE_ARRAY;
jbe@183 1207 container->pos = 0;
jbe@183 1208 // add opening bracket to output buffer:
jbe@183 1209 luaL_addchar(&buf, '[');
jbe@183 1210 break;
jbe@183 1211 default:
jbe@183 1212 // throw error if table type is unknown:
jbe@183 1213 json_export_tabletype_error:
jbe@183 1214 return luaL_error(L, "JSON export not possible for ambiguous table (cannot decide whether it is an object or array)");
jbe@183 1215 }
jbe@183 1216 break;
jbe@183 1217 default:
jbe@183 1218 // all other datatypes are considered an error:
jbe@183 1219 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 1220 }
jbe@187 1221 // check if a container is being processed:
jbe@183 1222 if (container) {
jbe@187 1223 // if yes,
jbe@187 1224 // execute code for container iteration:
jbe@184 1225 json_export_container:
jbe@187 1226 // distinguish between JSON objects and JSON arrays:
jbe@183 1227 switch (container->type) {
jbe@187 1228 // JSON object:
jbe@183 1229 case JSON_TABLETYPE_OBJECT:
jbe@187 1230 // finish iteration if all string keys have been processed:
jbe@185 1231 if (container->pos == container->count) goto json_export_close;
jbe@187 1232 // push current string key on top of stack:
jbe@185 1233 key = &container->keys[container->pos];
jbe@185 1234 lua_pushlstring(L, key->data, key->length);
jbe@187 1235 // check if the key has already been exported:
jbe@185 1236 if (!containerkey) {
jbe@187 1237 // if no,
jbe@187 1238 // add a comma to the output buffer if necessary:
jbe@185 1239 if (container->pos) luaL_addchar(&buf, ',');
jbe@187 1240 // set containerkey variable to true:
jbe@185 1241 containerkey = 1;
jbe@183 1242 } else {
jbe@187 1243 // if a key has already been exported,
jbe@187 1244 // add a colon to the output buffer:
jbe@185 1245 luaL_addchar(&buf, ':');
jbe@187 1246 // add a space to the output buffer for pretty results:
jbe@185 1247 if (pretty) luaL_addchar(&buf, ' ');
jbe@187 1248 // replace string key on top of stack with corresponding value:
jbe@185 1249 lua_rawget(L, json_export_luacontainer_idx);
jbe@187 1250 // reset containerkey variable
jbe@185 1251 containerkey = 0;
jbe@187 1252 // increase number of processed key value pairs:
jbe@185 1253 container->pos++;
jbe@163 1254 }
jbe@187 1255 // store key or value on top of stack in designated stack position:
jbe@185 1256 lua_replace(L, json_export_value_idx);
jbe@183 1257 break;
jbe@187 1258 // JSON array:
jbe@183 1259 case JSON_TABLETYPE_ARRAY:
jbe@187 1260 // store next value in designated stack position:
jbe@185 1261 lua_rawgeti(L, json_export_luacontainer_idx, container->pos+1);
jbe@183 1262 lua_replace(L, json_export_value_idx);
jbe@187 1263 // finish iteration if value is nil:
jbe@185 1264 if (lua_isnil(L, json_export_value_idx)) goto json_export_close;
jbe@187 1265 // add a comma to the output buffer if necessary:
jbe@185 1266 if (container->pos) luaL_addchar(&buf, ',');
jbe@187 1267 // increase number of processed values:
jbe@185 1268 container->pos++;
jbe@183 1269 break;
jbe@187 1270 // common code for closing JSON objects or JSON arrays:
jbe@183 1271 json_export_close:
jbe@187 1272 // decrement level variable:
jbe@185 1273 level--;
jbe@187 1274 // handle indentation for pretty results:
jbe@187 1275 if (pretty && container->pos) {
jbe@187 1276 luaL_addchar(&buf, '\n');
jbe@187 1277 for (i=0; i<level; i++) {
jbe@187 1278 lua_pushvalue(L, json_export_indentstring_idx);
jbe@187 1279 luaL_addvalue(&buf);
jbe@185 1280 }
jbe@164 1281 }
jbe@187 1282 // add closing bracket to output buffer:
jbe@185 1283 luaL_addchar(&buf, container->type == JSON_TABLETYPE_OBJECT ? '}' : ']');
jbe@187 1284 // finish export if last level has been closed:
jbe@185 1285 if (!level) goto json_export_finish;
jbe@187 1286 // otherwise,
jbe@187 1287 // recall previous container information from stack swap
jbe@187 1288 // and set C pointer to corresponding C struct:
jbe@185 1289 lua_rawgeti(L, json_export_stackswap_idx, stackswapidx--);
jbe@185 1290 lua_replace(L, json_export_ccontainer_idx);
jbe@185 1291 container = lua_touserdata(L, json_export_ccontainer_idx);
jbe@185 1292 lua_rawgeti(L, json_export_stackswap_idx, stackswapidx--);
jbe@185 1293 lua_replace(L, json_export_luacontainer_idx);
jbe@187 1294 // repeat code for container iteration:
jbe@185 1295 goto json_export_container;
jbe@164 1296 }
jbe@184 1297 // handle indentation for pretty results:
jbe@185 1298 if (pretty && (containerkey || container->type == JSON_TABLETYPE_ARRAY)) {
jbe@185 1299 luaL_addchar(&buf, '\n');
jbe@185 1300 for (i=0; i<level; i++) {
jbe@185 1301 lua_pushvalue(L, json_export_indentstring_idx);
jbe@185 1302 luaL_addvalue(&buf);
jbe@164 1303 }
jbe@154 1304 }
jbe@183 1305 } else {
jbe@187 1306 // if no container is being processed,
jbe@187 1307 // finish export:
jbe@185 1308 json_export_finish:
jbe@185 1309 // for pretty results, add final newline character if outermost container is processed:
jbe@185 1310 if (pretty) luaL_addchar(&buf, '\n');
jbe@187 1311 // create and return Lua string from buffer contents
jbe@154 1312 luaL_pushresult(&buf);
jbe@154 1313 return 1;
jbe@154 1314 }
jbe@154 1315 }
jbe@164 1316 }
jbe@164 1317
jbe@149 1318 // functions in library module:
jbe@121 1319 static const struct luaL_Reg json_module_functions[] = {
jbe@133 1320 {"object", json_object},
jbe@173 1321 {"array", json_array},
jbe@121 1322 {"import", json_import},
jbe@154 1323 {"export", json_export},
jbe@173 1324 {"get", json_get},
jbe@173 1325 {"type", json_type},
jbe@173 1326 {"set", json_set},
jbe@121 1327 {NULL, NULL}
jbe@121 1328 };
jbe@121 1329
jbe@149 1330 // metamethods for JSON objects, JSON arrays, and unknown JSON collections (object or array):
jbe@126 1331 static const struct luaL_Reg json_metatable_functions[] = {
jbe@130 1332 {"__len", json_len},
jbe@130 1333 {"__index", json_index},
jbe@130 1334 {"__newindex", json_newindex},
jbe@135 1335 {"__pairs", json_pairs},
jbe@134 1336 {"__ipairs", json_ipairs},
jbe@160 1337 {"__tostring", json_export},
jbe@126 1338 {NULL, NULL}
jbe@126 1339 };
jbe@126 1340
jbe@157 1341 // metamethods for JSON null marker:
jbe@157 1342 static const struct luaL_Reg json_nullmark_metamethods[] = {
jbe@157 1343 {"__tostring", json_nullmark_tostring},
jbe@157 1344 {NULL, NULL}
jbe@157 1345 };
jbe@157 1346
jbe@149 1347 // initializes json library:
jbe@121 1348 int luaopen_json(lua_State *L) {
jbe@149 1349 // empty stack:
jbe@126 1350 lua_settop(L, 0);
jbe@149 1351 // push library module onto stack position 1:
jbe@149 1352 lua_newtable(L);
jbe@149 1353 // register library functions:
jbe@149 1354 luaL_setfuncs(L, json_module_functions, 0);
jbe@149 1355 // create and store objectmt:
jbe@138 1356 lua_newtable(L);
jbe@138 1357 luaL_setfuncs(L, json_metatable_functions, 0);
jbe@144 1358 json_regstore(L, objectmt);
jbe@149 1359 // create and store arraymt:
jbe@138 1360 lua_newtable(L);
jbe@138 1361 luaL_setfuncs(L, json_metatable_functions, 0);
jbe@144 1362 json_regstore(L, arraymt);
jbe@157 1363 // set metatable of null marker and make it available through library module:
jbe@157 1364 json_pushnullmark(L);
jbe@157 1365 lua_newtable(L);
jbe@157 1366 luaL_setfuncs(L, json_nullmark_metamethods, 0);
jbe@157 1367 lua_setmetatable(L, -2);
jbe@157 1368 lua_setfield(L, 1, "null");
jbe@157 1369 // return library module (that's expected on top of stack):
jbe@121 1370 return 1;
jbe@121 1371 }

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