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annotate libraries/json/json.c @ 524:50746f1e8a43

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Fixed typo in documentation
author jbe
date Tue Aug 22 01:35:09 2017 +0200 (2017-08-22)
parents 43a4b74b5b18
children
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@432 6 #include <stdint.h>
jbe@432 7 /* TODO: stdint.h only needed for Lua 5.2 compatibility */
jbe@121 8
jbe@144 9 // maximum number of nested JSON values (objects and arrays):
jbe@182 10 // NOTE: json_import can store 2^32 / 3 levels on stack swap (using
jbe@183 11 // also negative indicies after integer wraparound), and
jbe@183 12 // json_export can store even more levels, so 1024^3 =
jbe@183 13 // 1073741824 is a safe value and allows practically unlimited
jbe@183 14 // levels for JSON documents <= 2 GiB.
jbe@182 15 #define JSON_MAXDEPTH (1024*1024*1024)
jbe@142 16
jbe@193 17 // define type JSON_LIGHTUSERDATA and
jbe@193 18 // generate dummy memory addresses for lightuserdata values:
jbe@193 19 #define JSON_LIGHTUSERDATA char
jbe@193 20 static struct {
jbe@193 21 JSON_LIGHTUSERDATA nullmark; // lightuserdata value represents a NULL value
jbe@193 22 JSON_LIGHTUSERDATA shadowtbl; // lightuserdata key for shadow table
jbe@193 23 } json_lightuserdata;
jbe@193 24
jbe@193 25 // macros for special nullmark value:
jbe@193 26 #define json_isnullmark(L, i) (lua_touserdata((L), (i)) == &json_lightuserdata.nullmark)
jbe@193 27 #define json_pushnullmark(L) lua_pushlightuserdata((L), &json_lightuserdata.nullmark)
jbe@193 28
jbe@193 29 // macros for getting and setting shadow tables
jbe@193 30 #define json_setshadow(L, i) lua_rawsetp((L), (i), &json_lightuserdata.shadowtbl)
jbe@193 31 #define json_getshadow(L, i) lua_rawgetp((L), (i), &json_lightuserdata.shadowtbl)
jbe@193 32 #define json_createproxy(L) lua_createtable((L), 0, 1)
jbe@193 33
jbe@193 34 // generate additional dummy memory addresses that represent Lua objects
jbe@193 35 // via lightuserdata keys and LUA_REGISTRYINDEX:
jbe@193 36 static struct {
jbe@193 37 JSON_LIGHTUSERDATA objectmt; // metatable for JSON objects
jbe@193 38 JSON_LIGHTUSERDATA arraymt; // metatable for JSON arrays
jbe@193 39 } json_registry;
jbe@155 40
jbe@144 41 // macros for usage of Lua registry:
jbe@145 42 #define json_regpointer(x) (&json_registry.x)
jbe@151 43 #define json_regfetchpointer(L, x) lua_rawgetp((L), LUA_REGISTRYINDEX, (x))
jbe@151 44 #define json_regfetch(L, x) json_regfetchpointer(L, json_regpointer(x))
jbe@151 45 #define json_regstore(L, x) lua_rawsetp(L, LUA_REGISTRYINDEX, json_regpointer(x))
jbe@145 46
jbe@157 47 // returns the string "<JSON null marker>":
jbe@157 48 static int json_nullmark_tostring(lua_State *L) {
jbe@157 49 lua_pushliteral(L, "<JSON null marker>");
jbe@157 50 return 1;
jbe@157 51 }
jbe@157 52
jbe@202 53 #define json_object_source_idx 1
jbe@202 54 #define json_object_iterator_idx 2
jbe@202 55 #define json_object_output_idx 3
jbe@202 56 #define json_object_shadow_idx 4
jbe@202 57 #define json_object_iterfun_idx 5
jbe@202 58 #define json_object_itertbl_idx 6
jbe@169 59
jbe@202 60 // converts a Lua table (or any other iterable value) to a JSON object:
jbe@169 61 // (does never modify the argument, returns an empty object or array if argument is nil)
jbe@202 62 static int json_object(lua_State *L) {
jbe@171 63 // determine is argument is given:
jbe@202 64 if (lua_isnoneornil(L, json_object_source_idx)) {
jbe@171 65 // if no argument is given (or if argument is nil),
jbe@193 66 // create proxy table with shadow table, and leave proxy table on top of stack:
jbe@193 67 json_createproxy(L);
jbe@169 68 lua_newtable(L);
jbe@193 69 json_setshadow(L, -2);
jbe@169 70 } else {
jbe@171 71 // if an argument was given,
jbe@193 72 // stack shall contain only one function argument:
jbe@171 73 lua_settop(L, 1);
jbe@193 74 // check if there is an iterator function in its metatable:
jbe@202 75 if (luaL_getmetafield(L, json_object_source_idx, "__pairs")) {
jbe@193 76 // if there is an iterator function,
jbe@193 77 // leave it on stack position 2 and verify its type:
jbe@202 78 if (lua_type(L, json_object_iterator_idx) != LUA_TFUNCTION)
jbe@202 79 return luaL_error(L, "__pairs metamethod is not a function");
jbe@169 80 } else {
jbe@193 81 // if there is no iterator function,
jbe@193 82 // verify the type of the argument itself:
jbe@202 83 luaL_checktype(L, json_object_source_idx, LUA_TTABLE);
jbe@193 84 // push nil onto stack position 2:
jbe@169 85 lua_pushnil(L);
jbe@143 86 }
jbe@171 87 // create result table on stack position 3:
jbe@193 88 json_createproxy(L);
jbe@169 89 // create shadow table on stack position 4:
jbe@169 90 lua_newtable(L);
jbe@193 91 lua_pushvalue(L, -1);
jbe@193 92 json_setshadow(L, -3);
jbe@171 93 // check if iterator function exists:
jbe@202 94 if (lua_isnil(L, json_object_iterator_idx)) {
jbe@171 95 // if there is no iterator function,
jbe@202 96 // copy all string key value pairs to shadow table:
jbe@202 97 for (lua_pushnil(L); lua_next(L, json_object_source_idx); lua_pop(L, 1)) {
jbe@202 98 if (lua_type(L, -2) == LUA_TSTRING) {
jbe@202 99 lua_pushvalue(L, -2);
jbe@202 100 lua_pushvalue(L, -2);
jbe@202 101 lua_rawset(L, json_object_shadow_idx);
jbe@171 102 }
jbe@169 103 }
jbe@169 104 } else {
jbe@172 105 // if there is an iterator function,
jbe@172 106 // call iterator function with source value (first argument)
jbe@172 107 // and store 3 result values on stack positions 5 through 7:
jbe@202 108 lua_pushvalue(L, json_object_iterator_idx);
jbe@172 109 lua_pushvalue(L, 1);
jbe@172 110 lua_call(L, 1, 3);
jbe@175 111 // iterate through key value pairs and store some of them in shadow table
jbe@174 112 // while replacing nil values with null-marker:
jbe@172 113 while (1) {
jbe@175 114 // call iterfun function:
jbe@202 115 lua_pushvalue(L, json_object_iterfun_idx);
jbe@202 116 lua_pushvalue(L, json_object_itertbl_idx);
jbe@172 117 lua_pushvalue(L, -3);
jbe@172 118 lua_remove(L, -4);
jbe@172 119 lua_call(L, 2, 2);
jbe@175 120 // break iteration loop if key is nil:
jbe@172 121 if (lua_isnil(L, -2)) break;
jbe@175 122 // store key value pair only if key type is correct:
jbe@202 123 if (lua_type(L, -2) == LUA_TSTRING) {
jbe@175 124 // if key type is correct,
jbe@175 125 // push key onto stack:
jbe@172 126 lua_pushvalue(L, -2);
jbe@175 127 // if value is nil, push null-marker onto stack (as value):
jbe@174 128 if (lua_isnil(L, -2)) json_pushnullmark(L);
jbe@175 129 // else push value onto stack:
jbe@174 130 else lua_pushvalue(L, -2);
jbe@175 131 // set key value pair in shadow table:
jbe@202 132 lua_rawset(L, json_object_shadow_idx);
jbe@172 133 }
jbe@175 134 // pop value from stack, but leave key on stack:
jbe@172 135 lua_pop(L, 1);
jbe@172 136 }
jbe@143 137 }
jbe@171 138 // let result table be on top of stack:
jbe@202 139 lua_settop(L, json_object_output_idx);
jbe@136 140 }
jbe@171 141 // set metatable (for result table on top of stack):
jbe@202 142 json_regfetch(L, objectmt);
jbe@169 143 lua_setmetatable(L, -2);
jbe@171 144 // return table on top of stack:
jbe@136 145 return 1;
jbe@136 146 }
jbe@136 147
jbe@202 148 #define json_array_source_idx 1
jbe@202 149 #define json_array_output_idx 2
jbe@202 150 #define json_array_shadow_idx 3
jbe@136 151
jbe@175 152 // converts a Lua table (or any other iterable value) to a JSON array:
jbe@175 153 // (does never modify the argument, returns an empty object or array if argument is nil)
jbe@136 154 static int json_array(lua_State *L) {
jbe@202 155 // determine is argument is given:
jbe@202 156 if (lua_isnoneornil(L, json_array_source_idx)) {
jbe@202 157 // if no argument is given (or if argument is nil),
jbe@202 158 // create proxy table with shadow table, and leave proxy table on top of stack:
jbe@202 159 json_createproxy(L);
jbe@202 160 lua_newtable(L);
jbe@202 161 json_setshadow(L, -2);
jbe@202 162 } else {
jbe@202 163 lua_Integer arrayidx, arraylen;
jbe@202 164 // if an argument was given,
jbe@202 165 // stack shall contain only one function argument:
jbe@202 166 lua_settop(L, 1);
jbe@202 167 // create result table on stack position 2:
jbe@202 168 json_createproxy(L);
jbe@202 169 // create shadow table on stack position 3:
jbe@202 170 lua_newtable(L);
jbe@202 171 lua_pushvalue(L, -1);
jbe@202 172 json_setshadow(L, -3);
jbe@202 173 // determine length of array:
jbe@202 174 arraylen = luaL_len(L, json_array_source_idx);
jbe@202 175 // for an array, copy consecutive integer value pairs to shadow table:
jbe@202 176 for (arrayidx=0; arrayidx<arraylen; ) {
jbe@202 177 // increment arrayidx at head of loop:
jbe@202 178 arrayidx++;
jbe@202 179 // get next array entry:
jbe@202 180 lua_pushinteger(L, arrayidx);
jbe@202 181 lua_gettable(L, json_array_source_idx);
jbe@202 182 // check if value is nil:
jbe@202 183 if (lua_isnil(L, -1)) {
jbe@202 184 // if yes, replace it with null-marker:
jbe@202 185 lua_pop(L, 1);
jbe@202 186 json_pushnullmark(L);
jbe@202 187 }
jbe@202 188 // store value in shadow table:
jbe@202 189 lua_rawseti(L, json_array_shadow_idx, arrayidx);
jbe@202 190 }
jbe@202 191 // let result table be on top of stack:
jbe@202 192 lua_settop(L, json_array_output_idx);
jbe@202 193 }
jbe@202 194 // set metatable (for result table on top of stack):
jbe@202 195 json_regfetch(L, arraymt);
jbe@202 196 lua_setmetatable(L, -2);
jbe@202 197 // return table on top of stack:
jbe@202 198 return 1;
jbe@136 199 }
jbe@136 200
jbe@145 201 // internal states of JSON parser:
jbe@124 202 #define JSON_STATE_VALUE 0
jbe@124 203 #define JSON_STATE_OBJECT_KEY 1
jbe@124 204 #define JSON_STATE_OBJECT_KEY_TERMINATOR 2
jbe@124 205 #define JSON_STATE_OBJECT_VALUE 3
jbe@124 206 #define JSON_STATE_OBJECT_SEPARATOR 4
jbe@124 207 #define JSON_STATE_ARRAY_VALUE 5
jbe@124 208 #define JSON_STATE_ARRAY_SEPARATOR 6
jbe@124 209 #define JSON_STATE_END 7
jbe@121 210
jbe@145 211 // special Lua stack indicies for json_import function:
jbe@138 212 #define json_import_objectmt_idx 2
jbe@138 213 #define json_import_arraymt_idx 3
jbe@193 214 #define json_import_stackswap_idx 4
jbe@138 215
jbe@168 216 // macros for hex decoding:
jbe@168 217 #define json_utf16_surrogate(x) ((x) >= 0xD800 && (x) <= 0xDFFF)
jbe@168 218 #define json_utf16_lead(x) ((x) >= 0xD800 && (x) <= 0xDBFF)
jbe@168 219 #define json_utf16_tail(x) ((x) >= 0xDC00 && (x) <= 0xDFFF)
jbe@167 220 #define json_import_readhex(x) \
jbe@167 221 do { \
jbe@167 222 x = 0; \
jbe@167 223 for (i=0; i<4; i++) { \
jbe@167 224 x <<= 4; \
jbe@167 225 c = str[pos++]; \
jbe@167 226 if (c >= '0' && c <= '9') x += c - '0'; \
jbe@167 227 else if (c >= 'A' && c <= 'F') x += c - 'A' + 10; \
jbe@167 228 else if (c >= 'a' && c <= 'f') x += c - 'a' + 10; \
jbe@167 229 else if (c == 0) goto json_import_unexpected_eof; \
jbe@167 230 else goto json_import_unexpected_escape; \
jbe@167 231 } \
jbe@167 232 } while (0)
jbe@167 233
jbe@136 234 // decodes a JSON document:
jbe@121 235 static int json_import(lua_State *L) {
jbe@181 236 int stackswapidx = 0; // elements in stack swap table
jbe@181 237 int i; // loop variable
jbe@181 238 const char *str; // string to parse
jbe@181 239 size_t total; // total length of string to parse
jbe@181 240 size_t pos = 0; // current position in string to parse
jbe@181 241 size_t level = 0; // nested levels of objects/arrays currently being processed
jbe@145 242 int mode = JSON_STATE_VALUE; // state of parser (i.e. "what's expected next?")
jbe@181 243 unsigned char c; // variable to store a single character to be processed (unsigned!)
jbe@181 244 luaL_Buffer luabuf; // Lua buffer to decode JSON string values
jbe@181 245 char *cbuf; // C buffer to decode JSON string values
jbe@181 246 size_t outlen; // maximum length or write position of C buffer
jbe@181 247 long codepoint; // decoded UTF-16 character or higher codepoint
jbe@181 248 long utf16tail; // second decoded UTF-16 character (surrogate tail)
jbe@181 249 size_t arraylen; // variable to temporarily store the array length
jbe@166 250 // require string as argument and convert to C string with length information:
jbe@166 251 str = luaL_checklstring(L, 1, &total);
jbe@166 252 // if string contains a NULL byte, this is a syntax error
jbe@166 253 if (strlen(str) != total) goto json_import_syntax_error;
jbe@147 254 // stack shall contain one function argument:
jbe@138 255 lua_settop(L, 1);
jbe@147 256 // push objectmt onto stack position 2:
jbe@144 257 json_regfetch(L, objectmt);
jbe@147 258 // push arraymt onto stack position 3:
jbe@144 259 json_regfetch(L, arraymt);
jbe@181 260 // push table for stack swapping onto stack position 5:
jbe@181 261 // (needed to avoid Lua stack overflows)
jbe@181 262 lua_newtable(L);
jbe@136 263 // main loop of parser:
jbe@136 264 json_import_loop:
jbe@136 265 // skip whitespace and store next character in variable 'c':
jbe@146 266 while (c = str[pos],
jbe@146 267 c == ' ' ||
jbe@146 268 c == '\f' ||
jbe@146 269 c == '\n' ||
jbe@146 270 c == '\r' ||
jbe@146 271 c == '\t' ||
jbe@146 272 c == '\v'
jbe@146 273 ) pos++;
jbe@170 274 // NOTE: variable c needs to be unsigned in the following code
jbe@136 275 // switch statement to handle certain (single) characters:
jbe@121 276 switch (c) {
jbe@136 277 // handle end of JSON document:
jbe@121 278 case 0:
jbe@136 279 // if end of JSON document was expected, then return top element of stack as result:
jbe@124 280 if (mode == JSON_STATE_END) return 1;
jbe@136 281 // otherwise, the JSON document was malformed:
jbe@167 282 if (level == 0) {
jbe@167 283 lua_pushnil(L);
jbe@167 284 lua_pushliteral(L, "Empty string");
jbe@167 285 } else {
jbe@167 286 json_import_unexpected_eof:
jbe@167 287 lua_pushnil(L);
jbe@167 288 lua_pushliteral(L, "Unexpected end of JSON document");
jbe@167 289 }
jbe@121 290 return 2;
jbe@181 291 // new JSON object or JSON array:
jbe@121 292 case '{':
jbe@181 293 case '[':
jbe@181 294 // if an encountered JSON object is not expected here, then return an error:
jbe@146 295 if (
jbe@181 296 c == '{' &&
jbe@181 297 mode != JSON_STATE_VALUE &&
jbe@181 298 mode != JSON_STATE_OBJECT_VALUE &&
jbe@181 299 mode != JSON_STATE_ARRAY_VALUE
jbe@181 300 ) goto json_import_syntax_error;
jbe@181 301 // if an encountered JSON array is not expected here, then return an error:
jbe@181 302 if (
jbe@181 303 c == '[' &&
jbe@146 304 mode != JSON_STATE_VALUE &&
jbe@146 305 mode != JSON_STATE_OBJECT_VALUE &&
jbe@146 306 mode != JSON_STATE_ARRAY_VALUE
jbe@146 307 ) goto json_import_syntax_error;
jbe@181 308 // consume input character:
jbe@181 309 pos++;
jbe@181 310 // limit nested levels:
jbe@181 311 if (level >= JSON_MAXDEPTH) {
jbe@181 312 lua_pushnil(L);
jbe@181 313 lua_pushfstring(L, "More than %d nested JSON levels", JSON_MAXDEPTH);
jbe@181 314 return 2;
jbe@181 315 }
jbe@181 316 // swap Lua stack entries for previous level to swap table:
jbe@181 317 // (avoids depth limitations due to Lua stack size)
jbe@181 318 if (level) {
jbe@181 319 lua_rawseti(L, json_import_stackswap_idx, ++stackswapidx);
jbe@181 320 lua_rawseti(L, json_import_stackswap_idx, ++stackswapidx);
jbe@181 321 lua_rawseti(L, json_import_stackswap_idx, ++stackswapidx);
jbe@181 322 }
jbe@181 323 // increment level:
jbe@181 324 level++;
jbe@181 325 // create JSON object or JSON array on stack:
jbe@136 326 lua_newtable(L);
jbe@181 327 // set metatable of JSON object or JSON array:
jbe@181 328 lua_pushvalue(L, c == '{' ? json_import_objectmt_idx : json_import_arraymt_idx);
jbe@125 329 lua_setmetatable(L, -2);
jbe@136 330 // create internal shadow table on stack:
jbe@136 331 lua_newtable(L);
jbe@146 332 // register internal shadow table:
jbe@193 333 lua_pushvalue(L, -1);
jbe@193 334 json_setshadow(L, -3);
jbe@181 335 // distinguish between JSON objects and JSON arrays:
jbe@181 336 if (c == '{') {
jbe@181 337 // if JSON object,
jbe@181 338 // expect object key (or end of object) to follow:
jbe@181 339 mode = JSON_STATE_OBJECT_KEY;
jbe@181 340 } else {
jbe@181 341 // if JSON array,
jbe@181 342 // expect array value (or end of array) to follow:
jbe@181 343 mode = JSON_STATE_ARRAY_VALUE;
jbe@181 344 // add nil as key (needed to keep stack balance) and as magic to detect arrays:
jbe@181 345 if (c == '[') lua_pushnil(L);
jbe@142 346 }
jbe@121 347 goto json_import_loop;
jbe@136 348 // end of JSON object:
jbe@121 349 case '}':
jbe@136 350 // if end of JSON object is not expected here, then return an error:
jbe@146 351 if (
jbe@146 352 mode != JSON_STATE_OBJECT_KEY &&
jbe@146 353 mode != JSON_STATE_OBJECT_SEPARATOR
jbe@146 354 ) goto json_import_syntax_error;
jbe@136 355 // jump to common code for end of JSON object and JSON array:
jbe@121 356 goto json_import_close;
jbe@136 357 // end of JSON array:
jbe@121 358 case ']':
jbe@136 359 // if end of JSON array is not expected here, then return an error:
jbe@146 360 if (
jbe@146 361 mode != JSON_STATE_ARRAY_VALUE &&
jbe@146 362 mode != JSON_STATE_ARRAY_SEPARATOR
jbe@146 363 ) goto json_import_syntax_error;
jbe@146 364 // pop nil key/magic (that was needed to keep stack balance):
jbe@140 365 lua_pop(L, 1);
jbe@136 366 // continue with common code for end of JSON object and JSON array:
jbe@136 367 // common code for end of JSON object or JSON array:
jbe@121 368 json_import_close:
jbe@136 369 // consume input character:
jbe@121 370 pos++;
jbe@136 371 // pop shadow table:
jbe@136 372 lua_pop(L, 1);
jbe@136 373 // check if nested:
jbe@121 374 if (--level) {
jbe@146 375 // if nested,
jbe@181 376 // restore previous stack elements from stack swap:
jbe@181 377 lua_rawgeti(L, json_import_stackswap_idx, stackswapidx--);
jbe@181 378 lua_insert(L, -2);
jbe@181 379 lua_rawgeti(L, json_import_stackswap_idx, stackswapidx--);
jbe@181 380 lua_insert(L, -2);
jbe@181 381 lua_rawgeti(L, json_import_stackswap_idx, stackswapidx--);
jbe@181 382 lua_insert(L, -2);
jbe@146 383 // check if outer(!) structure is an array or object:
jbe@140 384 if (lua_isnil(L, -2)) {
jbe@136 385 // select array value processing:
jbe@124 386 mode = JSON_STATE_ARRAY_VALUE;
jbe@121 387 } else {
jbe@136 388 // select object value processing:
jbe@124 389 mode = JSON_STATE_OBJECT_VALUE;
jbe@121 390 }
jbe@136 391 // store value in outer structure:
jbe@121 392 goto json_import_process_value;
jbe@121 393 }
jbe@136 394 // if not nested, then expect end of JSON document and continue with loop:
jbe@136 395 mode = JSON_STATE_END;
jbe@121 396 goto json_import_loop;
jbe@136 397 // key terminator:
jbe@121 398 case ':':
jbe@136 399 // if key terminator is not expected here, then return an error:
jbe@124 400 if (mode != JSON_STATE_OBJECT_KEY_TERMINATOR)
jbe@121 401 goto json_import_syntax_error;
jbe@136 402 // consume input character:
jbe@121 403 pos++;
jbe@146 404 // expect object value to follow:
jbe@124 405 mode = JSON_STATE_OBJECT_VALUE;
jbe@146 406 // continue with loop:
jbe@121 407 goto json_import_loop;
jbe@136 408 // value terminator (NOTE: trailing comma at end of value or key-value list is tolerated by this parser)
jbe@121 409 case ',':
jbe@146 410 // branch according to parser state:
jbe@124 411 if (mode == JSON_STATE_OBJECT_SEPARATOR) {
jbe@146 412 // expect an object key to follow:
jbe@124 413 mode = JSON_STATE_OBJECT_KEY;
jbe@124 414 } else if (mode == JSON_STATE_ARRAY_SEPARATOR) {
jbe@146 415 // expect an array value to follow:
jbe@124 416 mode = JSON_STATE_ARRAY_VALUE;
jbe@121 417 } else {
jbe@136 418 // if value terminator is not expected here, then return an error:
jbe@136 419 goto json_import_syntax_error;
jbe@121 420 }
jbe@136 421 // consume input character:
jbe@121 422 pos++;
jbe@136 423 // continue with loop:
jbe@121 424 goto json_import_loop;
jbe@136 425 // string literal:
jbe@121 426 case '"':
jbe@146 427 // consume quote character:
jbe@146 428 pos++;
jbe@162 429 // find last character in input string:
jbe@162 430 outlen = pos;
jbe@162 431 while ((c = str[outlen]) != '"') {
jbe@161 432 // consume one character:
jbe@162 433 outlen++;
jbe@161 434 // handle unexpected end of JSON document:
jbe@161 435 if (c == 0) goto json_import_unexpected_eof;
jbe@161 436 // consume one extra character when encountering an escaped quote:
jbe@162 437 else if (c == '\\' && str[outlen] == '"') outlen++;
jbe@161 438 }
jbe@162 439 // determine buffer length:
jbe@162 440 outlen -= pos;
jbe@161 441 // check if string is non empty:
jbe@162 442 if (outlen) {
jbe@161 443 // prepare buffer to decode string (with maximum possible length) and set write position to zero:
jbe@162 444 cbuf = luaL_buffinitsize(L, &luabuf, outlen);
jbe@162 445 outlen = 0;
jbe@161 446 // loop through the characters until encountering end quote:
jbe@161 447 while ((c = str[pos++]) != '"') {
jbe@162 448 // NOTE: unexpected end cannot happen anymore
jbe@162 449 if (c < 32 || c == 127) {
jbe@161 450 // do not allow ASCII control characters:
jbe@161 451 // NOTE: illegal UTF-8 sequences and extended control characters are not sanitized
jbe@161 452 // by this parser to allow different encodings than Unicode
jbe@161 453 lua_pushnil(L);
jbe@161 454 lua_pushliteral(L, "Unexpected control character in JSON string");
jbe@161 455 return 2;
jbe@161 456 } else if (c == '\\') {
jbe@161 457 // read next char after backslash escape:
jbe@161 458 c = str[pos++];
jbe@161 459 switch (c) {
jbe@161 460 // unexpected end-of-string:
jbe@161 461 case 0:
jbe@161 462 goto json_import_unexpected_eof;
jbe@161 463 // unescaping of quotation mark, slash, and backslash:
jbe@161 464 case '"':
jbe@161 465 case '/':
jbe@161 466 case '\\':
jbe@162 467 cbuf[outlen++] = c;
jbe@161 468 break;
jbe@161 469 // unescaping of backspace:
jbe@162 470 case 'b': cbuf[outlen++] = '\b'; break;
jbe@161 471 // unescaping of form-feed:
jbe@162 472 case 'f': cbuf[outlen++] = '\f'; break;
jbe@161 473 // unescaping of new-line:
jbe@162 474 case 'n': cbuf[outlen++] = '\n'; break;
jbe@161 475 // unescaping of carriage-return:
jbe@162 476 case 'r': cbuf[outlen++] = '\r'; break;
jbe@161 477 // unescaping of tabulator:
jbe@162 478 case 't': cbuf[outlen++] = '\t'; break;
jbe@161 479 // unescaping of UTF-16 characters
jbe@161 480 case 'u':
jbe@167 481 // decode 4 hex nibbles:
jbe@167 482 json_import_readhex(codepoint);
jbe@167 483 // handle surrogate character:
jbe@167 484 if (json_utf16_surrogate(codepoint)) {
jbe@167 485 // check if first surrogate is in valid range:
jbe@167 486 if (json_utf16_lead(codepoint)) {
jbe@167 487 // require second surrogate:
jbe@167 488 if ((c = str[pos++]) != '\\' || (c = str[pos++]) != 'u') {
jbe@167 489 if (c == 0) goto json_import_unexpected_eof;
jbe@167 490 else goto json_import_wrong_surrogate;
jbe@167 491 }
jbe@167 492 // read 4 hex nibbles of second surrogate character:
jbe@167 493 json_import_readhex(utf16tail);
jbe@167 494 // check if second surrogate is in valid range:
jbe@167 495 if (!json_utf16_tail(utf16tail)) goto json_import_wrong_surrogate;
jbe@167 496 // calculate codepoint:
jbe@167 497 codepoint = 0x10000 + (utf16tail - 0xDC00) + (codepoint - 0xD800) * 0x400;
jbe@167 498 } else {
jbe@167 499 // throw error for wrong surrogates:
jbe@167 500 json_import_wrong_surrogate:
jbe@167 501 lua_pushnil(L);
jbe@167 502 lua_pushliteral(L, "Illegal UTF-16 surrogate in JSON string escape sequence");
jbe@167 503 return 2;
jbe@167 504 }
jbe@167 505 }
jbe@167 506 // encode as UTF-8:
jbe@167 507 if (codepoint < 0x80) {
jbe@167 508 cbuf[outlen++] = (char)codepoint;
jbe@167 509 } else if (codepoint < 0x800) {
jbe@167 510 cbuf[outlen++] = (char)(0xc0 | (codepoint >> 6));
jbe@167 511 cbuf[outlen++] = (char)(0x80 | (codepoint & 0x3f));
jbe@167 512 } else if (codepoint < 0x10000) {
jbe@167 513 cbuf[outlen++] = (char)(0xe0 | (codepoint >> 12));
jbe@167 514 cbuf[outlen++] = (char)(0x80 | ((codepoint >> 6) & 0x3f));
jbe@167 515 cbuf[outlen++] = (char)(0x80 | (codepoint & 0x3f));
jbe@167 516 } else {
jbe@167 517 cbuf[outlen++] = (char)(0xf0 | (codepoint >> 18));
jbe@167 518 cbuf[outlen++] = (char)(0x80 | ((codepoint >> 12) & 0x3f));
jbe@167 519 cbuf[outlen++] = (char)(0x80 | ((codepoint >> 6) & 0x3f));
jbe@167 520 cbuf[outlen++] = (char)(0x80 | (codepoint & 0x3f));
jbe@167 521 }
jbe@167 522 break;
jbe@161 523 // unexpected escape sequence:
jbe@161 524 default:
jbe@167 525 json_import_unexpected_escape:
jbe@161 526 lua_pushnil(L);
jbe@161 527 lua_pushliteral(L, "Unexpected string escape sequence in JSON document");
jbe@161 528 return 2;
jbe@161 529 }
jbe@161 530 } else {
jbe@161 531 // normal character:
jbe@162 532 cbuf[outlen++] = c;
jbe@121 533 }
jbe@121 534 }
jbe@161 535 // process buffer to Lua string:
jbe@162 536 luaL_pushresultsize(&luabuf, outlen);
jbe@161 537 } else {
jbe@161 538 // if JSON string is empty,
jbe@161 539 // push empty Lua string:
jbe@161 540 lua_pushliteral(L, "");
jbe@167 541 // consume closing quote:
jbe@167 542 pos++;
jbe@121 543 }
jbe@136 544 // continue with processing of decoded string:
jbe@121 545 goto json_import_process_value;
jbe@121 546 }
jbe@136 547 // process values whose type is is not deducible from a single character:
jbe@136 548 if ((c >= '0' && c <= '9') || c == '-' || c == '+') {
jbe@427 549 // try to parse number:
jbe@167 550 double numval;
jbe@122 551 char *endptr;
jbe@427 552 size_t endpos;
jbe@427 553 // use strtod() call to parse a (double precision) floating point number
jbe@427 554 // and to determine length of number:
jbe@122 555 numval = strtod(str+pos, &endptr);
jbe@146 556 // catch parsing errors:
jbe@122 557 if (endptr == str+pos) goto json_import_syntax_error;
jbe@427 558 // calculate end position of number:
jbe@427 559 endpos = endptr - str;
jbe@427 560 #if LUA_VERSION_NUM >= 503
jbe@427 561 // try alternative integer interpretation:
jbe@427 562 {
jbe@427 563 lua_Integer intval = 0;
jbe@427 564 size_t curpos;
jbe@427 565 if (c >= '0' && c <= '9') intval = c - '0';
jbe@427 566 for (curpos=pos+1; curpos<endpos; curpos++) {
jbe@427 567 lua_Integer d = str[curpos] - '0';
jbe@427 568 if (d < 0 || d > 9) break;
jbe@427 569 if (c == '-') {
jbe@427 570 // NOTE: rounding of negative integer division may be undefined
jbe@427 571 if (
jbe@427 572 intval == LUA_MININTEGER ||
jbe@427 573 -intval > (-(LUA_MININTEGER+10) - d) / 10 + 1
jbe@427 574 ) break;
jbe@427 575 intval = 10 * intval - d;
jbe@427 576 } else {
jbe@427 577 if (intval > (LUA_MAXINTEGER - d) / 10) break;
jbe@427 578 intval = 10 * intval + d;
jbe@427 579 }
jbe@427 580 }
jbe@441 581 // push result onto Lua stack:
jbe@427 582 if (curpos == endpos) lua_pushinteger(L, intval);
jbe@427 583 else lua_pushnumber(L, numval);
jbe@427 584 }
jbe@441 585 #else
jbe@441 586 // push result onto Lua stack:
jbe@441 587 lua_pushnumber(L, numval);
jbe@427 588 #endif
jbe@146 589 // consume characters that were parsed:
jbe@427 590 pos = endpos;
jbe@122 591 } else if (!strncmp(str+pos, "true", 4)) {
jbe@136 592 // consume 4 input characters for "true":
jbe@121 593 pos += 4;
jbe@147 594 // put Lua true value onto stack:
jbe@136 595 lua_pushboolean(L, 1);
jbe@121 596 } else if (!strncmp(str+pos, "false", 5)) {
jbe@136 597 // consume 5 input characters for "false":
jbe@121 598 pos += 5;
jbe@147 599 // put Lua false value onto stack:
jbe@136 600 lua_pushboolean(L, 0);
jbe@121 601 } else if (!strncmp(str+pos, "null", 4)) {
jbe@136 602 // consume 4 input characters for "null":
jbe@136 603 pos += 4;
jbe@194 604 // push special null-marker onto stack:
jbe@194 605 json_pushnullmark(L);
jbe@121 606 } else {
jbe@136 607 // all other cases are a syntax error:
jbe@121 608 goto json_import_syntax_error;
jbe@121 609 }
jbe@136 610 // process a decoded value or key value pair (expected on top of Lua stack):
jbe@136 611 json_import_process_value:
jbe@121 612 switch (mode) {
jbe@136 613 // an object key has been read:
jbe@124 614 case JSON_STATE_OBJECT_KEY:
jbe@136 615 // if an object key is not a string, then this is a syntax error:
jbe@121 616 if (lua_type(L, -1) != LUA_TSTRING) goto json_import_syntax_error;
jbe@146 617 // expect key terminator to follow:
jbe@124 618 mode = JSON_STATE_OBJECT_KEY_TERMINATOR;
jbe@146 619 // continue with loop:
jbe@121 620 goto json_import_loop;
jbe@136 621 // a key value pair has been read:
jbe@124 622 case JSON_STATE_OBJECT_VALUE:
jbe@136 623 // store key value pair in outer shadow table:
jbe@130 624 lua_rawset(L, -3);
jbe@146 625 // expect value terminator (or end of object) to follow:
jbe@124 626 mode = JSON_STATE_OBJECT_SEPARATOR;
jbe@146 627 // continue with loop:
jbe@121 628 goto json_import_loop;
jbe@136 629 // an array value has been read:
jbe@124 630 case JSON_STATE_ARRAY_VALUE:
jbe@152 631 // get current array length:
jbe@152 632 arraylen = lua_rawlen(L, -3);
jbe@427 633 // throw error if array would exceed INT_MAX-1 elements:
jbe@427 634 // NOTE: Lua 5.3 may support more elements, but C libraries may not
jbe@427 635 if (arraylen > INT_MAX-1) {
jbe@152 636 lua_pushnil(L);
jbe@427 637 lua_pushfstring(L, "Array exceeded length of %d elements", INT_MAX-1);
jbe@152 638 }
jbe@136 639 // store value in outer shadow table:
jbe@152 640 lua_rawseti(L, -3, arraylen + 1);
jbe@146 641 // expect value terminator (or end of object) to follow:
jbe@124 642 mode = JSON_STATE_ARRAY_SEPARATOR;
jbe@146 643 // continue with loop
jbe@121 644 goto json_import_loop;
jbe@136 645 // a single value has been read:
jbe@124 646 case JSON_STATE_VALUE:
jbe@136 647 // leave value on top of stack, expect end of JSON document, and continue with loop:
jbe@124 648 mode = JSON_STATE_END;
jbe@121 649 goto json_import_loop;
jbe@121 650 }
jbe@146 651 // syntax error handling (reachable by goto statement):
jbe@136 652 json_import_syntax_error:
jbe@121 653 lua_pushnil(L);
jbe@121 654 lua_pushliteral(L, "Syntax error in JSON document");
jbe@121 655 return 2;
jbe@121 656 }
jbe@121 657
jbe@146 658 // gets a value or its type from a JSON document (passed as first argument)
jbe@175 659 // using a path (passed as variable number of keys after the first argument):
jbe@137 660 static int json_path(lua_State *L, int type_mode) {
jbe@193 661 int stacktop; // number of arguments
jbe@193 662 int idx = 2; // stack index of current argument to process
jbe@173 663 // require at least one argument:
jbe@173 664 luaL_checkany(L, 1);
jbe@193 665 // store stack index of top of stack (number of arguments):
jbe@138 666 stacktop = lua_gettop(L);
jbe@146 667 // use first argument as "current value" (stored on top of stack):
jbe@193 668 lua_pushvalue(L, 1);
jbe@146 669 // process each "path key" (2nd argument and following arguments):
jbe@138 670 while (idx <= stacktop) {
jbe@146 671 // if "current value" (on top of stack) is nil, then the path cannot be walked and nil is returned:
jbe@137 672 if (lua_isnil(L, -1)) return 1;
jbe@137 673 // try to get shadow table of "current value":
jbe@193 674 json_getshadow(L, -1);
jbe@126 675 if (lua_isnil(L, -1)) {
jbe@137 676 // if no shadow table is found,
jbe@193 677 if (lua_type(L, -2) == LUA_TTABLE) {
jbe@146 678 // and if "current value" is a table,
jbe@193 679 // pop nil from stack:
jbe@146 680 lua_pop(L, 1);
jbe@137 681 // get "next value" using the "path key":
jbe@130 682 lua_pushvalue(L, idx++);
jbe@130 683 lua_gettable(L, -2);
jbe@130 684 } else {
jbe@137 685 // if "current value" is not a table,
jbe@146 686 // then the path cannot be walked and nil (already on top of stack) is returned:
jbe@137 687 return 1;
jbe@130 688 }
jbe@130 689 } else {
jbe@137 690 // if a shadow table is found,
jbe@137 691 // set "current value" to its shadow table:
jbe@130 692 lua_replace(L, -2);
jbe@137 693 // get "next value" using the "path key":
jbe@130 694 lua_pushvalue(L, idx++);
jbe@130 695 lua_rawget(L, -2);
jbe@126 696 }
jbe@137 697 // the "next value" replaces the "current value":
jbe@130 698 lua_replace(L, -2);
jbe@126 699 }
jbe@137 700 if (!type_mode) {
jbe@137 701 // if a value (and not its type) was requested,
jbe@137 702 // check if value is the null-marker, and store nil on top of Lua stack in that case:
jbe@155 703 if (json_isnullmark(L, -1)) lua_pushnil(L);
jbe@137 704 } else {
jbe@137 705 // if the type was requested,
jbe@137 706 // check if value is the null-marker:
jbe@155 707 if (json_isnullmark(L, -1)) {
jbe@137 708 // if yes, store string "null" on top of Lua stack:
jbe@130 709 lua_pushliteral(L, "null");
jbe@137 710 } else {
jbe@137 711 // otherwise,
jbe@138 712 // check if metatable indicates "object" or "array":
jbe@138 713 if (lua_getmetatable(L, -1)) {
jbe@144 714 json_regfetch(L, objectmt);
jbe@138 715 if (lua_rawequal(L, -2, -1)) {
jbe@146 716 // if value has metatable for JSON objects,
jbe@138 717 // return string "object":
jbe@138 718 lua_pushliteral(L, "object");
jbe@138 719 return 1;
jbe@138 720 }
jbe@144 721 json_regfetch(L, arraymt);
jbe@138 722 if (lua_rawequal(L, -3, -1)) {
jbe@146 723 // if value has metatable for JSON arrays,
jbe@146 724 // return string "object":
jbe@138 725 lua_pushliteral(L, "array");
jbe@138 726 return 1;
jbe@138 727 }
jbe@146 728 // remove 3 metatables (one of the value, two for comparison) from stack:
jbe@138 729 lua_pop(L, 3);
jbe@138 730 }
jbe@138 731 // otherwise, get the Lua type:
jbe@138 732 lua_pushstring(L, lua_typename(L, lua_type(L, -1)));
jbe@126 733 }
jbe@126 734 }
jbe@137 735 // return the top most value on the Lua stack:
jbe@137 736 return 1;
jbe@130 737 }
jbe@130 738
jbe@147 739 // gets a value from a JSON document (passed as first argument)
jbe@175 740 // using a path (passed as variable number of keys after the first argument):
jbe@130 741 static int json_get(lua_State *L) {
jbe@137 742 return json_path(L, 0);
jbe@130 743 }
jbe@130 744
jbe@147 745 // gets a value's type from a JSON document (passed as first argument)
jbe@175 746 // using a path (passed as variable number of keys after first the argument):
jbe@130 747 static int json_type(lua_State *L) {
jbe@137 748 return json_path(L, 1);
jbe@130 749 }
jbe@130 750
jbe@173 751 // special Lua stack indicies for json_set function:
jbe@193 752 #define json_set_objectmt_idx 1
jbe@193 753 #define json_set_arraymt_idx 2
jbe@173 754
jbe@173 755 // stack offset of arguments to json_set function:
jbe@193 756 #define json_set_idxshift 2
jbe@173 757
jbe@173 758 // sets a value (passed as second argument) in a JSON document (passed as first argument)
jbe@175 759 // using a path (passed as variable number of keys starting at third argument):
jbe@173 760 static int json_set(lua_State *L) {
jbe@193 761 int stacktop; // stack index of top of stack (after shifting)
jbe@193 762 int idx; // stack index of current argument to process
jbe@199 763 // require at least three arguments:
jbe@173 764 luaL_checkany(L, 1);
jbe@173 765 luaL_checkany(L, 2);
jbe@199 766 luaL_checkany(L, 3);
jbe@193 767 // insert objectmt into stack at position 1 (shifting the arguments):
jbe@173 768 json_regfetch(L, objectmt);
jbe@193 769 lua_insert(L, 1);
jbe@193 770 // insert arraymt into stack at position 2 (shifting the arguments):
jbe@193 771 json_regfetch(L, arraymt);
jbe@173 772 lua_insert(L, 2);
jbe@173 773 // store stack index of top of stack:
jbe@173 774 stacktop = lua_gettop(L);
jbe@173 775 // use nil as initial "parent value":
jbe@173 776 lua_pushnil(L);
jbe@173 777 // use first argument as "current value":
jbe@173 778 lua_pushvalue(L, 1 + json_set_idxshift);
jbe@173 779 // set all necessary values in path:
jbe@173 780 for (idx = 3 + json_set_idxshift; idx<=stacktop; idx++) {
jbe@173 781 // push metatable of "current value" onto stack:
jbe@173 782 if (!lua_getmetatable(L, -1)) lua_pushnil(L);
jbe@173 783 // distinguish according to type of path key:
jbe@173 784 switch (lua_type(L, idx)) {
jbe@173 785 case LUA_TSTRING:
jbe@173 786 // if path key is a string,
jbe@173 787 // check if "current value" is a JSON object (or table without metatable):
jbe@173 788 if (
jbe@173 789 lua_rawequal(L, -1, json_set_objectmt_idx) ||
jbe@173 790 (lua_isnil(L, -1) && lua_type(L, -2) == LUA_TTABLE)
jbe@173 791 ) {
jbe@173 792 // if "current value" is acceptable,
jbe@173 793 // pop metatable and leave "current value" on top of stack:
jbe@173 794 lua_pop(L, 1);
jbe@173 795 } else {
jbe@173 796 // if "current value" is not acceptable:
jbe@173 797 // pop metatable and "current value":
jbe@173 798 lua_pop(L, 2);
jbe@173 799 // throw error if parent element does not exist:
jbe@173 800 if (lua_isnil(L, -1)) return luaL_error(L, "Root element is not a JSON object");
jbe@173 801 // push new JSON object as "current value" onto stack:
jbe@193 802 json_createproxy(L);
jbe@173 803 // create and register shadow table:
jbe@173 804 lua_newtable(L);
jbe@193 805 json_setshadow(L, -2);
jbe@173 806 // set metatable of JSON object:
jbe@173 807 lua_pushvalue(L, json_set_objectmt_idx);
jbe@173 808 lua_setmetatable(L, -2);
jbe@173 809 // set entry in "parent value":
jbe@173 810 lua_pushvalue(L, idx-1);
jbe@173 811 lua_pushvalue(L, -2);
jbe@173 812 lua_settable(L, -4);
jbe@173 813 }
jbe@173 814 break;
jbe@173 815 case LUA_TNUMBER:
jbe@173 816 // if path key is a number,
jbe@173 817 // check if "current value" is a JSON array (or table without metatable):
jbe@173 818 if (
jbe@173 819 lua_rawequal(L, -1, json_set_arraymt_idx) ||
jbe@173 820 (lua_isnil(L, -1) && lua_type(L, -2) == LUA_TTABLE)
jbe@173 821 ) {
jbe@173 822 // if "current value" is acceptable,
jbe@173 823 // pop metatable and leave "current value" on top of stack:
jbe@173 824 lua_pop(L, 1);
jbe@173 825 } else {
jbe@173 826 // if "current value" is not acceptable:
jbe@173 827 // pop metatable and "current value":
jbe@173 828 lua_pop(L, 2);
jbe@173 829 // throw error if parent element does not exist:
jbe@173 830 if (lua_isnil(L, -1)) return luaL_error(L, "Root element is not a JSON array");
jbe@173 831 // push new JSON array as "current value" onto stack:
jbe@193 832 json_createproxy(L);
jbe@173 833 // create and register shadow table:
jbe@173 834 lua_newtable(L);
jbe@193 835 json_setshadow(L, -2);
jbe@173 836 // set metatable of JSON array:
jbe@173 837 lua_pushvalue(L, json_set_arraymt_idx);
jbe@173 838 lua_setmetatable(L, -2);
jbe@173 839 // set entry in "parent value":
jbe@173 840 lua_pushvalue(L, idx-1);
jbe@173 841 lua_pushvalue(L, -2);
jbe@173 842 lua_settable(L, -4);
jbe@173 843 }
jbe@173 844 break;
jbe@173 845 default:
jbe@173 846 return luaL_error(L, "Invalid path key of type %s", lua_typename(L, lua_type(L, idx)));
jbe@173 847 }
jbe@173 848 // check if last path element is being processed:
jbe@173 849 if (idx == stacktop) {
jbe@173 850 // if the last path element is being processed,
jbe@173 851 // set last path value in "current value" container:
jbe@173 852 lua_pushvalue(L, idx);
jbe@173 853 lua_pushvalue(L, 2 + json_set_idxshift);
jbe@173 854 lua_settable(L, -3);
jbe@173 855 } else {
jbe@173 856 // if the processed path element is not the last,
jbe@173 857 // use old "current value" as new "parent value"
jbe@173 858 lua_remove(L, -2);
jbe@173 859 // push new "current value" onto stack by performing a lookup:
jbe@173 860 lua_pushvalue(L, idx);
jbe@173 861 lua_gettable(L, -2);
jbe@173 862 }
jbe@173 863 }
jbe@173 864 // return first argument for convenience:
jbe@173 865 lua_settop(L, 1 + json_set_idxshift);
jbe@173 866 return 1;
jbe@173 867 }
jbe@173 868
jbe@147 869 // returns the length of a JSON array (or zero for a table without numeric keys):
jbe@130 870 static int json_len(lua_State *L) {
jbe@201 871 // require table as first argument:
jbe@201 872 luaL_checktype(L, 1, LUA_TTABLE);
jbe@147 873 // stack shall contain one function argument:
jbe@130 874 lua_settop(L, 1);
jbe@193 875 // push shadow table or nil onto stack:
jbe@193 876 json_getshadow(L, 1);
jbe@193 877 // pop nil from stack if no shadow table has been found:
jbe@193 878 if (lua_isnil(L, -1)) lua_pop(L, 1);
jbe@193 879 // return length of argument or shadow table:
jbe@463 880 #if LUA_VERSION_NUM >= 503
jbe@463 881 lua_pushinteger(L, lua_rawlen(L, -1));
jbe@463 882 #else
jbe@193 883 lua_pushnumber(L, lua_rawlen(L, -1));
jbe@463 884 #endif
jbe@123 885 return 1;
jbe@123 886 }
jbe@123 887
jbe@175 888 // __index metamethod for JSON objects and JSON arrays:
jbe@130 889 static int json_index(lua_State *L) {
jbe@201 890 // require table as first argument:
jbe@201 891 luaL_checktype(L, 1, LUA_TTABLE);
jbe@148 892 // stack shall contain two function arguments:
jbe@130 893 lua_settop(L, 2);
jbe@193 894 // replace first argument with its shadow table
jbe@193 895 // or throw error if no shadow table is found:
jbe@193 896 json_getshadow(L, 1);
jbe@139 897 if (lua_isnil(L, -1)) return luaL_error(L, "Shadow table not found");
jbe@193 898 lua_replace(L, 1);
jbe@148 899 // use key passed as second argument to lookup value in shadow table:
jbe@193 900 lua_rawget(L, 1);
jbe@148 901 // if value is null-marker, then push nil onto stack:
jbe@193 902 if (json_isnullmark(L, 2)) lua_pushnil(L);
jbe@148 903 // return either looked up value, or nil
jbe@127 904 return 1;
jbe@127 905 }
jbe@127 906
jbe@175 907 // __newindex metamethod for JSON objects and JSON arrays:
jbe@130 908 static int json_newindex(lua_State *L) {
jbe@201 909 // require table as first argument
jbe@201 910 luaL_checktype(L, 1, LUA_TTABLE);
jbe@148 911 // stack shall contain three function arguments:
jbe@130 912 lua_settop(L, 3);
jbe@193 913 // replace first argument with its shadow table
jbe@193 914 // or throw error if no shadow table is found:
jbe@193 915 json_getshadow(L, 1);
jbe@130 916 if (lua_isnil(L, -1)) return luaL_error(L, "Shadow table not found");
jbe@130 917 lua_replace(L, 1);
jbe@193 918 // second and third argument to write to shadow table:
jbe@130 919 lua_rawset(L, 1);
jbe@148 920 // return nothing:
jbe@148 921 return 0;
jbe@121 922 }
jbe@121 923
jbe@175 924 // function returned as first value by json_pairs function:
jbe@135 925 static int json_pairs_iterfunc(lua_State *L) {
jbe@201 926 // require table as first argument
jbe@201 927 luaL_checktype(L, 1, LUA_TTABLE);
jbe@149 928 // stack shall contain two function arguments:
jbe@135 929 lua_settop(L, 2);
jbe@200 930 // get next key value pair from shadow table (argument 1) using previous key (argument 2)
jbe@149 931 // and return nothing if there is no next pair:
jbe@193 932 if (!lua_next(L, 1)) return 0;
jbe@149 933 // replace null-marker with nil:
jbe@155 934 if (json_isnullmark(L, -1)) {
jbe@135 935 lua_pop(L, 1);
jbe@135 936 lua_pushnil(L);
jbe@135 937 }
jbe@149 938 // return key and value (or key and nil, if null-marker was found):
jbe@135 939 return 2;
jbe@135 940 }
jbe@135 941
jbe@149 942 // returns a triple such that 'for key, value in pairs(obj) do ... end'
jbe@175 943 // iterates through all key value pairs (including JSON null values represented as Lua nil):
jbe@135 944 static int json_pairs(lua_State *L) {
jbe@201 945 // require table as first argument
jbe@201 946 luaL_checktype(L, 1, LUA_TTABLE);
jbe@200 947 // return triple of function json_pairs_iterfunc, shadow table of first argument, and nil:
jbe@139 948 lua_pushcfunction(L, json_pairs_iterfunc);
jbe@200 949 json_getshadow(L, 1);
jbe@200 950 if (lua_isnil(L, -1)) return luaL_error(L, "Shadow table not found");
jbe@135 951 lua_pushnil(L);
jbe@135 952 return 3;
jbe@135 953 }
jbe@135 954
jbe@175 955 // function returned as first value by json_ipairs function:
jbe@134 956 static int json_ipairs_iterfunc(lua_State *L) {
jbe@152 957 lua_Integer idx;
jbe@201 958 // require table as first argument
jbe@201 959 luaL_checktype(L, 1, LUA_TTABLE);
jbe@149 960 // stack shall contain two function arguments:
jbe@134 961 lua_settop(L, 2);
jbe@149 962 // calculate new index by incrementing second argument:
jbe@134 963 idx = lua_tointeger(L, 2) + 1;
jbe@200 964 // do integer lookup in shadow table and store result on stack position 3:
jbe@200 965 lua_rawgeti(L, 1, idx);
jbe@149 966 // return nothing if there was no value:
jbe@200 967 if (lua_isnil(L, 3)) return 0;
jbe@149 968 // return new index and
jbe@149 969 // either the looked up value if it is not equal to the null-marker
jbe@149 970 // or nil instead of null-marker:
jbe@134 971 lua_pushinteger(L, idx);
jbe@200 972 if (json_isnullmark(L, 3)) lua_pushnil(L);
jbe@200 973 else lua_pushvalue(L, 3);
jbe@134 974 return 2;
jbe@134 975 }
jbe@134 976
jbe@149 977 // returns a triple such that 'for idx, value in ipairs(ary) do ... end'
jbe@175 978 // iterates through all values (including JSON null values represented as Lua nil):
jbe@134 979 static int json_ipairs(lua_State *L) {
jbe@201 980 // require table as first argument
jbe@201 981 luaL_checktype(L, 1, LUA_TTABLE);
jbe@200 982 // return triple of function json_ipairs_iterfunc, shadow table of first argument, and zero:
jbe@139 983 lua_pushcfunction(L, json_ipairs_iterfunc);
jbe@200 984 json_getshadow(L, 1);
jbe@200 985 if (lua_isnil(L, -1)) return luaL_error(L, "Shadow table not found");
jbe@134 986 lua_pushinteger(L, 0);
jbe@134 987 return 3;
jbe@134 988 }
jbe@134 989
jbe@175 990 // datatype representing a table key:
jbe@175 991 // (used for sorting)
jbe@163 992 typedef struct {
jbe@163 993 size_t length;
jbe@163 994 const char *data;
jbe@163 995 } json_key_t;
jbe@163 996
jbe@175 997 // comparation function for table keys to be passed to qsort function:
jbe@163 998 static int json_key_cmp(json_key_t *key1, json_key_t *key2) {
jbe@163 999 size_t pos = 0;
jbe@163 1000 unsigned char c1, c2;
jbe@163 1001 while (1) {
jbe@163 1002 if (key1->length > pos) {
jbe@163 1003 if (key2->length > pos) {
jbe@163 1004 c1 = key1->data[pos];
jbe@163 1005 c2 = key2->data[pos];
jbe@163 1006 if (c1 < c2) return -1;
jbe@163 1007 else if (c1 > c2) return 1;
jbe@163 1008 } else {
jbe@163 1009 return 1;
jbe@163 1010 }
jbe@163 1011 } else {
jbe@163 1012 if (key2->length > pos) {
jbe@163 1013 return -1;
jbe@163 1014 } else {
jbe@163 1015 return 0;
jbe@163 1016 }
jbe@163 1017 }
jbe@163 1018 pos++;
jbe@163 1019 }
jbe@163 1020 }
jbe@163 1021
jbe@175 1022 // constants for type detection of ambiguous tables:
jbe@154 1023 #define JSON_TABLETYPE_UNKNOWN 0
jbe@154 1024 #define JSON_TABLETYPE_OBJECT 1
jbe@154 1025 #define JSON_TABLETYPE_ARRAY 2
jbe@154 1026
jbe@183 1027 typedef struct {
jbe@183 1028 int type;
jbe@183 1029 int pos;
jbe@183 1030 int count;
jbe@183 1031 json_key_t keys[1]; // or more
jbe@183 1032 } json_container_t;
jbe@183 1033
jbe@183 1034 // special Lua stack indicies for json_export function:
jbe@183 1035 #define json_export_value_idx 1
jbe@183 1036 #define json_export_indentstring_idx 2
jbe@183 1037 #define json_export_objectmt_idx 3
jbe@183 1038 #define json_export_arraymt_idx 4
jbe@193 1039 #define json_export_stackswap_idx 5
jbe@193 1040 #define json_export_luacontainer_idx 6
jbe@193 1041 #define json_export_ccontainer_idx 7
jbe@193 1042 #define json_export_buffer_idx 8
jbe@164 1043
jbe@183 1044 // encodes a JSON document (passed as first argument)
jbe@187 1045 // optionally using indentation (indentation string or true passed as second argument)
jbe@183 1046 static int json_export(lua_State *L) {
jbe@183 1047 int pretty; // pretty printing on? (i.e. printing with indentation)
jbe@183 1048 luaL_Buffer buf; // Lua buffer containing result string
jbe@183 1049 lua_Number num; // number to encode
jbe@428 1050 char numstr[80]; // encoded number
jbe@428 1051 // (21 chars needed for sign, zero, point, 17 significant digits, and NULL byte)
jbe@428 1052 // (21 chars needed for sign, 19 digits INT64, and NULL byte)
jbe@428 1053 // (80 chars needed for sign, 78 digits INT256, and NULL byte)
jbe@428 1054 // (NOTE: we don't know the size of intmax_t and thus use 80)
jbe@183 1055 const char *str; // string to encode
jbe@183 1056 size_t strlen; // length of string to encode
jbe@183 1057 size_t strpos ; // position in string or position of current key
jbe@183 1058 unsigned char c; // character to encode (unsigned!)
jbe@183 1059 char hexcode[7]; // store for unicode hex escape sequence
jbe@183 1060 // NOTE: 7 bytes due to backslash, character 'u', 4 hex digits, and terminating NULL byte
jbe@183 1061 int tabletype; // table type: unknown, JSON object, or JSON array
jbe@183 1062 size_t keycount = 0; // number of string keys in object
jbe@185 1063 json_key_t *key; // pointer to C structure containing a string key
jbe@183 1064 int level = 0; // current depth level
jbe@183 1065 int i; // iteration variable for level dependent repetitions
jbe@183 1066 int stackswapidx = 0; // elements in stack swap table
jbe@183 1067 int containerkey = 0; // temporarily set to 1, if a container key is being encoded
jbe@183 1068 json_container_t *container = NULL; // pointer to current C struct for container information
jbe@183 1069 // stack shall contain two function arguments:
jbe@183 1070 lua_settop(L, 2);
jbe@188 1071 // check if pretty printing (with indentation) is desired:
jbe@188 1072 if (lua_toboolean(L, json_export_indentstring_idx)) {
jbe@188 1073 // if yes,
jbe@188 1074 // set pretty variable to 1:
jbe@188 1075 pretty = 1;
jbe@188 1076 // check if second argument is a boolean (true):
jbe@188 1077 if (lua_isboolean(L, json_export_indentstring_idx)) {
jbe@188 1078 // if yes,
jbe@188 1079 // use default indentation if indentation argument is boolean true:
jbe@188 1080 lua_pushliteral(L, " ");
jbe@188 1081 lua_replace(L, json_export_indentstring_idx);
jbe@188 1082 } else {
jbe@188 1083 // if no,
jbe@188 1084 // require second argument to be a string:
jbe@188 1085 luaL_checktype(L, json_export_indentstring_idx, LUA_TSTRING);
jbe@188 1086 }
jbe@188 1087 } else {
jbe@188 1088 // if no,
jbe@188 1089 // set pretty variable to 0:
jbe@188 1090 pretty = 0;
jbe@157 1091 }
jbe@183 1092 // push objectmt onto stack position 3:
jbe@183 1093 json_regfetch(L, objectmt);
jbe@183 1094 // push arraymt onto stack position 4:
jbe@183 1095 json_regfetch(L, arraymt);
jbe@193 1096 // push table for stack swapping onto stack position 5:
jbe@183 1097 lua_newtable(L);
jbe@193 1098 // create placeholders on stack positions 6 through 7:
jbe@187 1099 lua_settop(L, json_export_buffer_idx);
jbe@183 1100 // create Lua string buffer:
jbe@183 1101 luaL_buffinit(L, &buf);
jbe@183 1102 // loop:
jbe@183 1103 while (1) {
jbe@183 1104 // if value to encode is the null-marker, then treat it the same as nil:
jbe@183 1105 if (json_isnullmark(L, json_export_value_idx)) {
jbe@183 1106 lua_pushnil(L);
jbe@183 1107 lua_replace(L, json_export_value_idx);
jbe@164 1108 }
jbe@183 1109 // distinguish between different Lua types:
jbe@183 1110 switch (lua_type(L, json_export_value_idx)) {
jbe@183 1111 // value to encode is nil:
jbe@183 1112 case LUA_TNIL:
jbe@183 1113 // add string "null" to output buffer:
jbe@183 1114 luaL_addstring(&buf, "null");
jbe@183 1115 break;
jbe@183 1116 // value to encode is of type number:
jbe@183 1117 case LUA_TNUMBER:
jbe@428 1118 #if LUA_VERSION_NUM >= 503
jbe@428 1119 // handle integers:
jbe@428 1120 if (lua_isinteger(L, json_export_value_idx)) {
jbe@448 1121 snprintf(numstr, sizeof(numstr), "%ji", (intmax_t)lua_tointeger(L, json_export_value_idx));
jbe@428 1122 luaL_addstring(&buf, numstr);
jbe@428 1123 break;
jbe@428 1124 }
jbe@428 1125 #endif
jbe@183 1126 // convert value to double precision number:
jbe@183 1127 num = lua_tonumber(L, json_export_value_idx);
jbe@183 1128 // throw error if number is not-a-number:
jbe@183 1129 if (isnan(num)) return luaL_error(L, "JSON export not possible for NaN value");
jbe@183 1130 // throw error if number is positive or negative infinity:
jbe@183 1131 if (isinf(num)) return luaL_error(L, "JSON export not possible for infinite numbers");
jbe@429 1132 // check if float is integral:
jbe@432 1133 if ((double)trunc((double)num) == (double)num) {
jbe@433 1134 // use maximum precision:
jbe@448 1135 snprintf(numstr, sizeof(numstr), "%.17g", num); // NOTE: e.g. 12345678901234560
jbe@429 1136 } else {
jbe@429 1137 // determine necessary precision to represent double precision floating point number:
jbe@448 1138 snprintf(numstr, sizeof(numstr), "%.15g", num); // NOTE: e.g. 0.009 should not be 0.008999999999999999
jbe@448 1139 if (strtod(numstr, NULL) != num) snprintf(numstr, sizeof(numstr), "%.16g", num);
jbe@448 1140 if (strtod(numstr, NULL) != num) snprintf(numstr, sizeof(numstr), "%.17g", num);
jbe@429 1141 }
jbe@191 1142 // add string encoding of the number to the output buffer:
jbe@189 1143 luaL_addstring(&buf, numstr);
jbe@428 1144 #if LUA_VERSION_NUM >= 503
jbe@428 1145 // enforce trailing ".0" for floats unless exponential notation was chosen:
jbe@428 1146 {
jbe@428 1147 char *p;
jbe@428 1148 if (numstr[0] == '-' || numstr[0] == '+') p = numstr+1;
jbe@428 1149 else p = numstr;
jbe@428 1150 for (; *p; p++) if (*p < '0' || *p > '9') break;
jbe@428 1151 if (!*p) luaL_addstring(&buf, ".0");
jbe@428 1152 }
jbe@428 1153 #endif
jbe@183 1154 break;
jbe@183 1155 // value to encode is of type boolean:
jbe@183 1156 case LUA_TBOOLEAN:
jbe@183 1157 // add string "true" or "false" according to boolean value:
jbe@183 1158 luaL_addstring(&buf, lua_toboolean(L, json_export_value_idx) ? "true" : "false");
jbe@183 1159 break;
jbe@183 1160 // value to encode is of type string:
jbe@183 1161 case LUA_TSTRING:
jbe@183 1162 // add quoted and escaped string to output buffer:
jbe@183 1163 str = lua_tolstring(L, json_export_value_idx, &strlen);
jbe@183 1164 luaL_addchar(&buf, '"');
jbe@183 1165 strpos = 0;
jbe@183 1166 while (strpos < strlen) {
jbe@183 1167 c = str[strpos++];
jbe@183 1168 if (c == '"') luaL_addstring(&buf, "\\\"");
jbe@183 1169 else if (c == '\\') luaL_addstring(&buf, "\\\\");
jbe@183 1170 else if (c == 127) luaL_addstring(&buf, "\\u007F");
jbe@183 1171 else if (c >= 32) luaL_addchar(&buf, c);
jbe@183 1172 else if (c == '\b') luaL_addstring(&buf, "\\b");
jbe@183 1173 else if (c == '\f') luaL_addstring(&buf, "\\f");
jbe@183 1174 else if (c == '\n') luaL_addstring(&buf, "\\n");
jbe@183 1175 else if (c == '\r') luaL_addstring(&buf, "\\r");
jbe@183 1176 else if (c == '\t') luaL_addstring(&buf, "\\t");
jbe@183 1177 else if (c == '\v') luaL_addstring(&buf, "\\v");
jbe@183 1178 else {
jbe@448 1179 snprintf(hexcode, sizeof(hexcode), "\\u%04X", c);
jbe@183 1180 luaL_addstring(&buf, hexcode);
jbe@154 1181 }
jbe@154 1182 }
jbe@183 1183 luaL_addchar(&buf, '"');
jbe@183 1184 break;
jbe@183 1185 // value to encode is of type table (this includes JSON objects and JSON arrays):
jbe@183 1186 case LUA_TTABLE:
jbe@183 1187 // use table's metatable to try to determine type of table:
jbe@183 1188 tabletype = JSON_TABLETYPE_UNKNOWN;
jbe@188 1189 if (lua_getmetatable(L, json_export_value_idx)) {
jbe@183 1190 if (lua_rawequal(L, -1, json_export_objectmt_idx)) {
jbe@183 1191 tabletype = JSON_TABLETYPE_OBJECT;
jbe@183 1192 } else {
jbe@183 1193 if (lua_rawequal(L, -1, json_export_arraymt_idx)) {
jbe@183 1194 tabletype = JSON_TABLETYPE_ARRAY;
jbe@183 1195 } else {
jbe@183 1196 return luaL_error(L, "JSON export not possible for tables with nonsupported metatable");
jbe@183 1197 }
jbe@183 1198 }
jbe@183 1199 // reset stack (pop metatable from stack):
jbe@183 1200 lua_pop(L, 1);
jbe@183 1201 }
jbe@193 1202 // replace table with its shadow table if existent:
jbe@193 1203 json_getshadow(L, json_export_value_idx);
jbe@183 1204 if (lua_isnil(L, -1)) lua_pop(L, 1);
jbe@193 1205 else lua_replace(L, json_export_value_idx);
jbe@187 1206 // check if type of table is still undetermined
jbe@187 1207 // and optionally calculate number of string keys (keycount)
jbe@187 1208 // or set keycount to zero:
jbe@186 1209 keycount = 0;
jbe@183 1210 if (tabletype == JSON_TABLETYPE_UNKNOWN) {
jbe@187 1211 // if type of table is undetermined,
jbe@187 1212 // iterate over all keys:
jbe@188 1213 for (lua_pushnil(L); lua_next(L, json_export_value_idx); lua_pop(L, 1)) {
jbe@183 1214 switch (lua_type(L, -2)) {
jbe@183 1215 case LUA_TSTRING:
jbe@183 1216 // for string keys,
jbe@183 1217 // increase keycount (may avoid another iteration):
jbe@183 1218 keycount++;
jbe@183 1219 // if type of table was unknown, then type of table is a JSON object now:
jbe@183 1220 if (tabletype == JSON_TABLETYPE_UNKNOWN) tabletype = JSON_TABLETYPE_OBJECT;
jbe@183 1221 // if type of table was a JSON array, then the type of table is ambiguous now
jbe@183 1222 // and an error is thrown:
jbe@183 1223 else if (tabletype == JSON_TABLETYPE_ARRAY) goto json_export_tabletype_error;
jbe@183 1224 break;
jbe@183 1225 case LUA_TNUMBER:
jbe@183 1226 // for numeric keys,
jbe@183 1227 // if type of table was unknown, then type of table is a JSON array now:
jbe@183 1228 if (tabletype == JSON_TABLETYPE_UNKNOWN) tabletype = JSON_TABLETYPE_ARRAY;
jbe@183 1229 // if type of table was a JSON object, then the type of table is ambiguous now
jbe@183 1230 // and an error is thrown:
jbe@183 1231 else if (tabletype == JSON_TABLETYPE_OBJECT) goto json_export_tabletype_error;
jbe@183 1232 break;
jbe@183 1233 }
jbe@164 1234 }
jbe@163 1235 }
jbe@183 1236 // raise error if too many nested levels:
jbe@183 1237 if (level >= JSON_MAXDEPTH) {
jbe@183 1238 return luaL_error(L, "More than %d nested JSON levels", JSON_MAXDEPTH);
jbe@163 1239 }
jbe@183 1240 // store previous container information (if existent) on stack swap
jbe@183 1241 // and increase level variable:
jbe@183 1242 if (level++) {
jbe@183 1243 lua_pushvalue(L, json_export_luacontainer_idx);
jbe@183 1244 lua_rawseti(L, json_export_stackswap_idx, ++stackswapidx);
jbe@183 1245 lua_pushvalue(L, json_export_ccontainer_idx);
jbe@183 1246 lua_rawseti(L, json_export_stackswap_idx, ++stackswapidx);
jbe@183 1247 }
jbe@188 1248 // use value as current container:
jbe@188 1249 lua_pushvalue(L, json_export_value_idx);
jbe@188 1250 lua_replace(L, json_export_luacontainer_idx);
jbe@183 1251 // distinguish between JSON objects and JSON arrays:
jbe@183 1252 switch (tabletype) {
jbe@183 1253 // JSON object:
jbe@183 1254 case JSON_TABLETYPE_OBJECT:
jbe@183 1255 // calculate count of string keys unless it has been calculated before:
jbe@183 1256 if (!keycount) {
jbe@183 1257 for (lua_pushnil(L); lua_next(L, json_export_luacontainer_idx); lua_pop(L, 1)) {
jbe@183 1258 if (lua_type(L, -2) == LUA_TSTRING) keycount++;
jbe@164 1259 }
jbe@164 1260 }
jbe@186 1261 // allocate memory for C structure containing string keys and container iteration state:
jbe@186 1262 container = lua_newuserdata(L, sizeof(json_container_t) + (keycount-1) * sizeof(json_key_t));
jbe@187 1263 // store reference to C structure on designated stack position:
jbe@186 1264 lua_replace(L, json_export_ccontainer_idx);
jbe@186 1265 // initialize C structure for container state:
jbe@186 1266 container->type = JSON_TABLETYPE_OBJECT;
jbe@186 1267 container->count = keycount;
jbe@186 1268 container->pos = 0;
jbe@187 1269 // check if object contains any keys:
jbe@183 1270 if (keycount) {
jbe@187 1271 // if yes,
jbe@187 1272 // copy all string keys to the C structure (and reset container->pos again):
jbe@183 1273 for (lua_pushnil(L); lua_next(L, json_export_luacontainer_idx); lua_pop(L, 1)) {
jbe@183 1274 if (lua_type(L, -2) == LUA_TSTRING) {
jbe@183 1275 json_key_t *key = &container->keys[container->pos++];
jbe@183 1276 key->data = lua_tolstring(L, -2, &key->length);
jbe@183 1277 }
jbe@183 1278 }
jbe@183 1279 container->pos = 0;
jbe@183 1280 // sort C array using quicksort:
jbe@183 1281 qsort(container->keys, keycount, sizeof(json_key_t), (void *)json_key_cmp);
jbe@154 1282 }
jbe@183 1283 // add opening bracket to output buffer:
jbe@183 1284 luaL_addchar(&buf, '{');
jbe@183 1285 break;
jbe@183 1286 // JSON array:
jbe@183 1287 case JSON_TABLETYPE_ARRAY:
jbe@187 1288 // allocate memory for C structure for container iteration state:
jbe@183 1289 container = lua_newuserdata(L, sizeof(json_container_t) - sizeof(json_key_t));
jbe@187 1290 // store reference to C structure on designated stack position:
jbe@183 1291 lua_replace(L, json_export_ccontainer_idx);
jbe@187 1292 // initialize C structure for container state:
jbe@183 1293 container->type = JSON_TABLETYPE_ARRAY;
jbe@183 1294 container->pos = 0;
jbe@183 1295 // add opening bracket to output buffer:
jbe@183 1296 luaL_addchar(&buf, '[');
jbe@183 1297 break;
jbe@183 1298 default:
jbe@183 1299 // throw error if table type is unknown:
jbe@183 1300 json_export_tabletype_error:
jbe@183 1301 return luaL_error(L, "JSON export not possible for ambiguous table (cannot decide whether it is an object or array)");
jbe@183 1302 }
jbe@183 1303 break;
jbe@183 1304 default:
jbe@183 1305 // all other datatypes are considered an error:
jbe@183 1306 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 1307 }
jbe@187 1308 // check if a container is being processed:
jbe@183 1309 if (container) {
jbe@187 1310 // if yes,
jbe@187 1311 // execute code for container iteration:
jbe@184 1312 json_export_container:
jbe@187 1313 // distinguish between JSON objects and JSON arrays:
jbe@183 1314 switch (container->type) {
jbe@187 1315 // JSON object:
jbe@183 1316 case JSON_TABLETYPE_OBJECT:
jbe@187 1317 // finish iteration if all string keys have been processed:
jbe@185 1318 if (container->pos == container->count) goto json_export_close;
jbe@187 1319 // check if the key has already been exported:
jbe@185 1320 if (!containerkey) {
jbe@187 1321 // if no,
jbe@187 1322 // add a comma to the output buffer if necessary:
jbe@185 1323 if (container->pos) luaL_addchar(&buf, ',');
jbe@445 1324 // push current string key on top of stack:
jbe@445 1325 key = &container->keys[container->pos];
jbe@445 1326 lua_pushlstring(L, key->data, key->length);
jbe@187 1327 // set containerkey variable to true:
jbe@185 1328 containerkey = 1;
jbe@183 1329 } else {
jbe@187 1330 // if a key has already been exported,
jbe@187 1331 // add a colon to the output buffer:
jbe@185 1332 luaL_addchar(&buf, ':');
jbe@187 1333 // add a space to the output buffer for pretty results:
jbe@185 1334 if (pretty) luaL_addchar(&buf, ' ');
jbe@445 1335 // push current string key on top of stack:
jbe@445 1336 key = &container->keys[container->pos];
jbe@445 1337 lua_pushlstring(L, key->data, key->length);
jbe@187 1338 // replace string key on top of stack with corresponding value:
jbe@185 1339 lua_rawget(L, json_export_luacontainer_idx);
jbe@187 1340 // reset containerkey variable
jbe@185 1341 containerkey = 0;
jbe@187 1342 // increase number of processed key value pairs:
jbe@185 1343 container->pos++;
jbe@163 1344 }
jbe@187 1345 // store key or value on top of stack in designated stack position:
jbe@185 1346 lua_replace(L, json_export_value_idx);
jbe@183 1347 break;
jbe@187 1348 // JSON array:
jbe@183 1349 case JSON_TABLETYPE_ARRAY:
jbe@187 1350 // store next value in designated stack position:
jbe@185 1351 lua_rawgeti(L, json_export_luacontainer_idx, container->pos+1);
jbe@183 1352 lua_replace(L, json_export_value_idx);
jbe@187 1353 // finish iteration if value is nil:
jbe@185 1354 if (lua_isnil(L, json_export_value_idx)) goto json_export_close;
jbe@187 1355 // add a comma to the output buffer if necessary:
jbe@185 1356 if (container->pos) luaL_addchar(&buf, ',');
jbe@187 1357 // increase number of processed values:
jbe@185 1358 container->pos++;
jbe@183 1359 break;
jbe@187 1360 // common code for closing JSON objects or JSON arrays:
jbe@183 1361 json_export_close:
jbe@187 1362 // decrement level variable:
jbe@185 1363 level--;
jbe@187 1364 // handle indentation for pretty results:
jbe@187 1365 if (pretty && container->pos) {
jbe@187 1366 luaL_addchar(&buf, '\n');
jbe@187 1367 for (i=0; i<level; i++) {
jbe@187 1368 lua_pushvalue(L, json_export_indentstring_idx);
jbe@187 1369 luaL_addvalue(&buf);
jbe@185 1370 }
jbe@164 1371 }
jbe@187 1372 // add closing bracket to output buffer:
jbe@185 1373 luaL_addchar(&buf, container->type == JSON_TABLETYPE_OBJECT ? '}' : ']');
jbe@187 1374 // finish export if last level has been closed:
jbe@185 1375 if (!level) goto json_export_finish;
jbe@187 1376 // otherwise,
jbe@187 1377 // recall previous container information from stack swap
jbe@187 1378 // and set C pointer to corresponding C struct:
jbe@185 1379 lua_rawgeti(L, json_export_stackswap_idx, stackswapidx--);
jbe@185 1380 lua_replace(L, json_export_ccontainer_idx);
jbe@185 1381 container = lua_touserdata(L, json_export_ccontainer_idx);
jbe@185 1382 lua_rawgeti(L, json_export_stackswap_idx, stackswapidx--);
jbe@185 1383 lua_replace(L, json_export_luacontainer_idx);
jbe@187 1384 // repeat code for container iteration:
jbe@185 1385 goto json_export_container;
jbe@164 1386 }
jbe@184 1387 // handle indentation for pretty results:
jbe@185 1388 if (pretty && (containerkey || container->type == JSON_TABLETYPE_ARRAY)) {
jbe@185 1389 luaL_addchar(&buf, '\n');
jbe@185 1390 for (i=0; i<level; i++) {
jbe@185 1391 lua_pushvalue(L, json_export_indentstring_idx);
jbe@185 1392 luaL_addvalue(&buf);
jbe@164 1393 }
jbe@154 1394 }
jbe@183 1395 } else {
jbe@187 1396 // if no container is being processed,
jbe@187 1397 // finish export:
jbe@185 1398 json_export_finish:
jbe@185 1399 // for pretty results, add final newline character if outermost container is processed:
jbe@185 1400 if (pretty) luaL_addchar(&buf, '\n');
jbe@187 1401 // create and return Lua string from buffer contents
jbe@154 1402 luaL_pushresult(&buf);
jbe@154 1403 return 1;
jbe@154 1404 }
jbe@154 1405 }
jbe@164 1406 }
jbe@164 1407
jbe@149 1408 // functions in library module:
jbe@121 1409 static const struct luaL_Reg json_module_functions[] = {
jbe@133 1410 {"object", json_object},
jbe@173 1411 {"array", json_array},
jbe@121 1412 {"import", json_import},
jbe@154 1413 {"export", json_export},
jbe@173 1414 {"get", json_get},
jbe@173 1415 {"type", json_type},
jbe@173 1416 {"set", json_set},
jbe@121 1417 {NULL, NULL}
jbe@121 1418 };
jbe@121 1419
jbe@149 1420 // metamethods for JSON objects, JSON arrays, and unknown JSON collections (object or array):
jbe@126 1421 static const struct luaL_Reg json_metatable_functions[] = {
jbe@130 1422 {"__len", json_len},
jbe@130 1423 {"__index", json_index},
jbe@130 1424 {"__newindex", json_newindex},
jbe@135 1425 {"__pairs", json_pairs},
jbe@134 1426 {"__ipairs", json_ipairs},
jbe@160 1427 {"__tostring", json_export},
jbe@126 1428 {NULL, NULL}
jbe@126 1429 };
jbe@126 1430
jbe@157 1431 // metamethods for JSON null marker:
jbe@157 1432 static const struct luaL_Reg json_nullmark_metamethods[] = {
jbe@157 1433 {"__tostring", json_nullmark_tostring},
jbe@157 1434 {NULL, NULL}
jbe@157 1435 };
jbe@157 1436
jbe@149 1437 // initializes json library:
jbe@121 1438 int luaopen_json(lua_State *L) {
jbe@149 1439 // empty stack:
jbe@126 1440 lua_settop(L, 0);
jbe@149 1441 // push library module onto stack position 1:
jbe@149 1442 lua_newtable(L);
jbe@149 1443 // register library functions:
jbe@149 1444 luaL_setfuncs(L, json_module_functions, 0);
jbe@149 1445 // create and store objectmt:
jbe@138 1446 lua_newtable(L);
jbe@138 1447 luaL_setfuncs(L, json_metatable_functions, 0);
jbe@144 1448 json_regstore(L, objectmt);
jbe@149 1449 // create and store arraymt:
jbe@138 1450 lua_newtable(L);
jbe@138 1451 luaL_setfuncs(L, json_metatable_functions, 0);
jbe@144 1452 json_regstore(L, arraymt);
jbe@157 1453 // set metatable of null marker and make it available through library module:
jbe@157 1454 json_pushnullmark(L);
jbe@157 1455 lua_newtable(L);
jbe@157 1456 luaL_setfuncs(L, json_nullmark_metamethods, 0);
jbe@157 1457 lua_setmetatable(L, -2);
jbe@157 1458 lua_setfield(L, 1, "null");
jbe@157 1459 // return library module (that's expected on top of stack):
jbe@121 1460 return 1;
jbe@121 1461 }

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