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annotate libraries/json/json.c @ 174:070edea2a92f

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Bugfix in json.object and json.array functions: use null-marker for nil values
author jbe
date Fri Aug 01 20:29:30 2014 +0200 (2014-08-01)
parents f417c4b607ed
children 20e393d2e6e1
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@150 8 // NOTE: The Lua reference states that the stack may typically contain at least
jbe@150 9 // "a few thousand elements". Since every nested level consumes
jbe@150 10 // 3 elements on the Lua stack (the object/array, its shadow table,
jbe@150 11 // a string key or a placeholder), we limit the number of nested levels
jbe@150 12 // to 500. If a stack overflow would still happen in the import function,
jbe@150 13 // this is detected nevertheless and an error is thrown (instead of
jbe@150 14 // returning nil and an error string).
jbe@150 15 #define JSON_MAXDEPTH 500
jbe@142 16
jbe@155 17 // generate dummy memory addresses that represents null values:
jbe@155 18 char json_nullmark;
jbe@155 19 #define json_isnullmark(L, i) (lua_touserdata((L), (i)) == &json_nullmark)
jbe@155 20 #define json_pushnullmark(L) lua_pushlightuserdata((L), &json_nullmark)
jbe@155 21
jbe@144 22 // macros for usage of Lua registry:
jbe@144 23 #define JSON_REGENT char
jbe@145 24 #define JSON_REGPOINTER void *
jbe@145 25 #define json_regpointer(x) (&json_registry.x)
jbe@151 26 #define json_regfetchpointer(L, x) lua_rawgetp((L), LUA_REGISTRYINDEX, (x))
jbe@151 27 #define json_regfetch(L, x) json_regfetchpointer(L, json_regpointer(x))
jbe@151 28 #define json_regstore(L, x) lua_rawsetp(L, LUA_REGISTRYINDEX, json_regpointer(x))
jbe@145 29
jbe@144 30 // generate dummy memory addresses that represent Lua objects
jbe@145 31 // via lightuserdata keys and LUA_REGISTRYINDEX:
jbe@144 32 static struct {
jbe@145 33 JSON_REGENT shadowtbl; // ephemeron table that maps tables to their corresponding shadow table
jbe@145 34 JSON_REGENT objectmt; // metatable for JSON objects
jbe@145 35 JSON_REGENT arraymt; // metatable for JSON arrays
jbe@144 36 } json_registry;
jbe@138 37
jbe@157 38 // returns the string "<JSON null marker>":
jbe@157 39 static int json_nullmark_tostring(lua_State *L) {
jbe@157 40 lua_pushliteral(L, "<JSON null marker>");
jbe@157 41 return 1;
jbe@157 42 }
jbe@157 43
jbe@169 44 #define json_convert_source_idx 1
jbe@169 45 #define json_convert_iterator_idx 2
jbe@169 46 #define json_convert_output_idx 3
jbe@169 47 #define json_convert_shadow_idx 4
jbe@172 48 #define json_convert_iterfun_idx 5
jbe@172 49 #define json_convert_itertbl_idx 6
jbe@169 50
jbe@169 51 // converts a Lua table to a JSON object or JSON array:
jbe@169 52 // (does never modify the argument, returns an empty object or array if argument is nil)
jbe@169 53 static int json_convert(lua_State *L, int array) {
jbe@171 54 int arrayidx = 0;
jbe@171 55 // determine is argument is given:
jbe@169 56 if (lua_isnoneornil(L, json_convert_source_idx)) {
jbe@171 57 // if no argument is given (or if argument is nil),
jbe@171 58 // create table with shadow table, and leave first table on top of stack:
jbe@144 59 json_regfetch(L, shadowtbl);
jbe@169 60 lua_newtable(L);
jbe@169 61 lua_pushvalue(L, -1);
jbe@169 62 lua_newtable(L);
jbe@169 63 lua_rawset(L, -4);
jbe@169 64 } else {
jbe@171 65 // if an argument was given,
jbe@171 66 // push its iterator function on stack position 2 if existent,
jbe@169 67 // else push null for normal tables:
jbe@171 68 lua_settop(L, 1);
jbe@169 69 if (lua_getmetatable(L, json_convert_source_idx)) {
jbe@169 70 lua_getfield(L, -1, array ? "__ipairs" : "__pairs");
jbe@169 71 if (lua_isnil(L, -1)) luaL_checktype(L, 1, LUA_TTABLE);
jbe@169 72 else if (lua_type(L, -1) != LUA_TFUNCTION)
jbe@169 73 return luaL_error(L, "%s metamethod is not a function", array ? "__ipairs" : "__pairs");
jbe@169 74 lua_replace(L, -2);
jbe@169 75 } else {
jbe@169 76 lua_pushnil(L);
jbe@143 77 }
jbe@171 78 // create result table on stack position 3:
jbe@169 79 lua_newtable(L);
jbe@169 80 // create shadow table on stack position 4:
jbe@169 81 json_regfetch(L, shadowtbl);
jbe@169 82 lua_newtable(L);
jbe@169 83 lua_pushvalue(L, json_convert_output_idx);
jbe@169 84 lua_pushvalue(L, -2);
jbe@169 85 lua_rawset(L, -4);
jbe@169 86 lua_replace(L, -2);
jbe@171 87 // check if iterator function exists:
jbe@169 88 if (lua_isnil(L, json_convert_iterator_idx)) {
jbe@171 89 // if there is no iterator function,
jbe@171 90 // distinguish between objects and arrays:
jbe@171 91 if (array == 0) {
jbe@171 92 // for an object, copy all string key value pairs to shadow table:
jbe@171 93 for (lua_pushnil(L); lua_next(L, json_convert_source_idx); lua_pop(L, 1)) {
jbe@171 94 if (lua_type(L, -2) == LUA_TSTRING) {
jbe@171 95 lua_pushvalue(L, -2);
jbe@171 96 lua_pushvalue(L, -2);
jbe@171 97 lua_rawset(L, json_convert_shadow_idx);
jbe@171 98 }
jbe@171 99 }
jbe@171 100 } else {
jbe@171 101 // for an array, copy consecutive integer value pairs to shadow table:
jbe@171 102 while (1) {
jbe@171 103 // TODO: Lua 5.3 may support more elements
jbe@171 104 if (arrayidx == INT_MAX) {
jbe@171 105 lua_pushnumber(L, (size_t)INT_MAX+1);
jbe@171 106 lua_rawget(L, json_convert_source_idx);
jbe@171 107 if (lua_isnil(L, -1)) break;
jbe@171 108 return luaL_error(L, "Array exceeded length of %d elements", INT_MAX);
jbe@171 109 }
jbe@171 110 arrayidx++;
jbe@171 111 lua_rawgeti(L, json_convert_source_idx, arrayidx);
jbe@171 112 if (lua_isnil(L, -1)) break;
jbe@171 113 lua_rawseti(L, json_convert_shadow_idx, arrayidx);
jbe@171 114 }
jbe@169 115 }
jbe@169 116 } else {
jbe@172 117 // if there is an iterator function,
jbe@172 118 // call iterator function with source value (first argument)
jbe@172 119 // and store 3 result values on stack positions 5 through 7:
jbe@172 120 lua_pushvalue(L, json_convert_iterator_idx);
jbe@172 121 lua_pushvalue(L, 1);
jbe@172 122 lua_call(L, 1, 3);
jbe@174 123 // iterate through key value pairs and store them in shadow table
jbe@174 124 // while replacing nil values with null-marker:
jbe@172 125 while (1) {
jbe@172 126 lua_pushvalue(L, json_convert_iterfun_idx);
jbe@172 127 lua_pushvalue(L, json_convert_itertbl_idx);
jbe@172 128 lua_pushvalue(L, -3);
jbe@172 129 lua_remove(L, -4);
jbe@172 130 lua_call(L, 2, 2);
jbe@172 131 if (lua_isnil(L, -2)) break;
jbe@172 132 if (lua_type(L, -2) == (array ? LUA_TNUMBER : LUA_TSTRING)) {
jbe@172 133 lua_pushvalue(L, -2);
jbe@174 134 if (lua_isnil(L, -2)) json_pushnullmark(L);
jbe@174 135 else lua_pushvalue(L, -2);
jbe@172 136 lua_rawset(L, json_convert_shadow_idx);
jbe@172 137 }
jbe@172 138 lua_pop(L, 1);
jbe@172 139 }
jbe@143 140 }
jbe@171 141 // let result table be on top of stack:
jbe@169 142 lua_settop(L, json_convert_output_idx);
jbe@136 143 }
jbe@171 144 // set metatable (for result table on top of stack):
jbe@171 145 if (array == 0) json_regfetch(L, objectmt);
jbe@171 146 else json_regfetch(L, arraymt);
jbe@169 147 lua_setmetatable(L, -2);
jbe@171 148 // return table on top of stack:
jbe@136 149 return 1;
jbe@136 150 }
jbe@136 151
jbe@136 152 static int json_object(lua_State *L) {
jbe@169 153 return json_convert(L, 0);
jbe@136 154 }
jbe@136 155
jbe@136 156 static int json_array(lua_State *L) {
jbe@169 157 return json_convert(L, 1);
jbe@136 158 }
jbe@136 159
jbe@145 160 // internal states of JSON parser:
jbe@124 161 #define JSON_STATE_VALUE 0
jbe@124 162 #define JSON_STATE_OBJECT_KEY 1
jbe@124 163 #define JSON_STATE_OBJECT_KEY_TERMINATOR 2
jbe@124 164 #define JSON_STATE_OBJECT_VALUE 3
jbe@124 165 #define JSON_STATE_OBJECT_SEPARATOR 4
jbe@124 166 #define JSON_STATE_ARRAY_VALUE 5
jbe@124 167 #define JSON_STATE_ARRAY_SEPARATOR 6
jbe@124 168 #define JSON_STATE_END 7
jbe@121 169
jbe@145 170 // special Lua stack indicies for json_import function:
jbe@138 171 #define json_import_objectmt_idx 2
jbe@138 172 #define json_import_arraymt_idx 3
jbe@138 173 #define json_import_shadowtbl_idx 4
jbe@138 174
jbe@168 175 // macros for hex decoding:
jbe@168 176 #define json_utf16_surrogate(x) ((x) >= 0xD800 && (x) <= 0xDFFF)
jbe@168 177 #define json_utf16_lead(x) ((x) >= 0xD800 && (x) <= 0xDBFF)
jbe@168 178 #define json_utf16_tail(x) ((x) >= 0xDC00 && (x) <= 0xDFFF)
jbe@167 179 #define json_import_readhex(x) \
jbe@167 180 do { \
jbe@167 181 x = 0; \
jbe@167 182 for (i=0; i<4; i++) { \
jbe@167 183 x <<= 4; \
jbe@167 184 c = str[pos++]; \
jbe@167 185 if (c >= '0' && c <= '9') x += c - '0'; \
jbe@167 186 else if (c >= 'A' && c <= 'F') x += c - 'A' + 10; \
jbe@167 187 else if (c >= 'a' && c <= 'f') x += c - 'a' + 10; \
jbe@167 188 else if (c == 0) goto json_import_unexpected_eof; \
jbe@167 189 else goto json_import_unexpected_escape; \
jbe@167 190 } \
jbe@167 191 } while (0)
jbe@167 192
jbe@136 193 // decodes a JSON document:
jbe@121 194 static int json_import(lua_State *L) {
jbe@167 195 int i; // loop variable
jbe@136 196 const char *str; // string to parse
jbe@136 197 size_t total; // total length of string to parse
jbe@136 198 size_t pos = 0; // current position in string to parse
jbe@136 199 size_t level = 0; // nested levels of objects/arrays currently being processed
jbe@145 200 int mode = JSON_STATE_VALUE; // state of parser (i.e. "what's expected next?")
jbe@170 201 unsigned char c; // variable to store a single character to be processed (unsigned!)
jbe@145 202 luaL_Buffer luabuf; // Lua buffer to decode JSON string values
jbe@145 203 char *cbuf; // C buffer to decode JSON string values
jbe@162 204 size_t outlen; // maximum length or write position of C buffer
jbe@167 205 long codepoint; // decoded UTF-16 character or higher codepoint
jbe@167 206 long utf16tail; // second decoded UTF-16 character (surrogate tail)
jbe@152 207 size_t arraylen; // variable to temporarily store the array length
jbe@166 208 // require string as argument and convert to C string with length information:
jbe@166 209 str = luaL_checklstring(L, 1, &total);
jbe@166 210 // if string contains a NULL byte, this is a syntax error
jbe@166 211 if (strlen(str) != total) goto json_import_syntax_error;
jbe@147 212 // stack shall contain one function argument:
jbe@138 213 lua_settop(L, 1);
jbe@147 214 // push objectmt onto stack position 2:
jbe@144 215 json_regfetch(L, objectmt);
jbe@147 216 // push arraymt onto stack position 3:
jbe@144 217 json_regfetch(L, arraymt);
jbe@147 218 // push shadowtbl onto stack position 4:
jbe@144 219 json_regfetch(L, shadowtbl);
jbe@136 220 // main loop of parser:
jbe@136 221 json_import_loop:
jbe@136 222 // skip whitespace and store next character in variable 'c':
jbe@146 223 while (c = str[pos],
jbe@146 224 c == ' ' ||
jbe@146 225 c == '\f' ||
jbe@146 226 c == '\n' ||
jbe@146 227 c == '\r' ||
jbe@146 228 c == '\t' ||
jbe@146 229 c == '\v'
jbe@146 230 ) pos++;
jbe@170 231 // NOTE: variable c needs to be unsigned in the following code
jbe@136 232 // switch statement to handle certain (single) characters:
jbe@121 233 switch (c) {
jbe@136 234 // handle end of JSON document:
jbe@121 235 case 0:
jbe@136 236 // if end of JSON document was expected, then return top element of stack as result:
jbe@124 237 if (mode == JSON_STATE_END) return 1;
jbe@136 238 // otherwise, the JSON document was malformed:
jbe@167 239 if (level == 0) {
jbe@167 240 lua_pushnil(L);
jbe@167 241 lua_pushliteral(L, "Empty string");
jbe@167 242 } else {
jbe@167 243 json_import_unexpected_eof:
jbe@167 244 lua_pushnil(L);
jbe@167 245 lua_pushliteral(L, "Unexpected end of JSON document");
jbe@167 246 }
jbe@121 247 return 2;
jbe@136 248 // new JSON object:
jbe@121 249 case '{':
jbe@136 250 // if a JSON object is not expected here, then return an error:
jbe@146 251 if (
jbe@146 252 mode != JSON_STATE_VALUE &&
jbe@146 253 mode != JSON_STATE_OBJECT_VALUE &&
jbe@146 254 mode != JSON_STATE_ARRAY_VALUE
jbe@146 255 ) goto json_import_syntax_error;
jbe@136 256 // create JSON object on stack:
jbe@136 257 lua_newtable(L);
jbe@136 258 // set metatable of JSON object:
jbe@138 259 lua_pushvalue(L, json_import_objectmt_idx);
jbe@125 260 lua_setmetatable(L, -2);
jbe@136 261 // create internal shadow table on stack:
jbe@136 262 lua_newtable(L);
jbe@146 263 // register internal shadow table:
jbe@123 264 lua_pushvalue(L, -2);
jbe@123 265 lua_pushvalue(L, -2);
jbe@138 266 lua_rawset(L, json_import_shadowtbl_idx);
jbe@146 267 // expect object key (or end of object) to follow:
jbe@136 268 mode = JSON_STATE_OBJECT_KEY;
jbe@146 269 // jump to common code for opening JSON object and JSON array:
jbe@142 270 goto json_import_open;
jbe@136 271 // new JSON array:
jbe@121 272 case '[':
jbe@136 273 // if a JSON array is not expected here, then return an error:
jbe@146 274 if (
jbe@146 275 mode != JSON_STATE_VALUE &&
jbe@146 276 mode != JSON_STATE_OBJECT_VALUE &&
jbe@146 277 mode != JSON_STATE_ARRAY_VALUE
jbe@146 278 ) goto json_import_syntax_error;
jbe@136 279 // create JSON array on stack:
jbe@136 280 lua_newtable(L);
jbe@136 281 // set metatable of JSON array:
jbe@138 282 lua_pushvalue(L, json_import_arraymt_idx);
jbe@125 283 lua_setmetatable(L, -2);
jbe@136 284 // create internal shadow table on stack:
jbe@136 285 lua_newtable(L);
jbe@146 286 // register internal shadow table:
jbe@123 287 lua_pushvalue(L, -2);
jbe@123 288 lua_pushvalue(L, -2);
jbe@138 289 lua_rawset(L, json_import_shadowtbl_idx);
jbe@140 290 // add nil as key (needed to keep stack balance) and as magic to detect arrays:
jbe@140 291 lua_pushnil(L);
jbe@146 292 // expect array value (or end of array) to follow:
jbe@142 293 mode = JSON_STATE_ARRAY_VALUE;
jbe@142 294 // continue with common code for opening JSON object and JSON array:
jbe@146 295 // common code for opening JSON object or JSON array:
jbe@142 296 json_import_open:
jbe@142 297 // limit nested levels:
jbe@142 298 if (level >= JSON_MAXDEPTH) {
jbe@142 299 lua_pushnil(L);
jbe@164 300 lua_pushfstring(L, "More than %d nested JSON levels", JSON_MAXDEPTH);
jbe@142 301 return 2;
jbe@142 302 }
jbe@142 303 // additional buffer overflow protection:
jbe@142 304 if (!lua_checkstack(L, LUA_MINSTACK))
jbe@142 305 return luaL_error(L, "Caught stack overflow in JSON import function (too many nested levels and stack size too small)");
jbe@136 306 // increment level:
jbe@121 307 level++;
jbe@142 308 // consume input character:
jbe@142 309 pos++;
jbe@121 310 goto json_import_loop;
jbe@136 311 // end of JSON object:
jbe@121 312 case '}':
jbe@136 313 // if end of JSON object is not expected here, then return an error:
jbe@146 314 if (
jbe@146 315 mode != JSON_STATE_OBJECT_KEY &&
jbe@146 316 mode != JSON_STATE_OBJECT_SEPARATOR
jbe@146 317 ) goto json_import_syntax_error;
jbe@136 318 // jump to common code for end of JSON object and JSON array:
jbe@121 319 goto json_import_close;
jbe@136 320 // end of JSON array:
jbe@121 321 case ']':
jbe@136 322 // if end of JSON array is not expected here, then return an error:
jbe@146 323 if (
jbe@146 324 mode != JSON_STATE_ARRAY_VALUE &&
jbe@146 325 mode != JSON_STATE_ARRAY_SEPARATOR
jbe@146 326 ) goto json_import_syntax_error;
jbe@146 327 // pop nil key/magic (that was needed to keep stack balance):
jbe@140 328 lua_pop(L, 1);
jbe@136 329 // continue with common code for end of JSON object and JSON array:
jbe@136 330 // common code for end of JSON object or JSON array:
jbe@121 331 json_import_close:
jbe@136 332 // consume input character:
jbe@121 333 pos++;
jbe@136 334 // pop shadow table:
jbe@136 335 lua_pop(L, 1);
jbe@136 336 // check if nested:
jbe@121 337 if (--level) {
jbe@146 338 // if nested,
jbe@146 339 // check if outer(!) structure is an array or object:
jbe@140 340 if (lua_isnil(L, -2)) {
jbe@136 341 // select array value processing:
jbe@124 342 mode = JSON_STATE_ARRAY_VALUE;
jbe@121 343 } else {
jbe@136 344 // select object value processing:
jbe@124 345 mode = JSON_STATE_OBJECT_VALUE;
jbe@121 346 }
jbe@136 347 // store value in outer structure:
jbe@121 348 goto json_import_process_value;
jbe@121 349 }
jbe@136 350 // if not nested, then expect end of JSON document and continue with loop:
jbe@136 351 mode = JSON_STATE_END;
jbe@121 352 goto json_import_loop;
jbe@136 353 // key terminator:
jbe@121 354 case ':':
jbe@136 355 // if key terminator is not expected here, then return an error:
jbe@124 356 if (mode != JSON_STATE_OBJECT_KEY_TERMINATOR)
jbe@121 357 goto json_import_syntax_error;
jbe@136 358 // consume input character:
jbe@121 359 pos++;
jbe@146 360 // expect object value to follow:
jbe@124 361 mode = JSON_STATE_OBJECT_VALUE;
jbe@146 362 // continue with loop:
jbe@121 363 goto json_import_loop;
jbe@136 364 // value terminator (NOTE: trailing comma at end of value or key-value list is tolerated by this parser)
jbe@121 365 case ',':
jbe@146 366 // branch according to parser state:
jbe@124 367 if (mode == JSON_STATE_OBJECT_SEPARATOR) {
jbe@146 368 // expect an object key to follow:
jbe@124 369 mode = JSON_STATE_OBJECT_KEY;
jbe@124 370 } else if (mode == JSON_STATE_ARRAY_SEPARATOR) {
jbe@146 371 // expect an array value to follow:
jbe@124 372 mode = JSON_STATE_ARRAY_VALUE;
jbe@121 373 } else {
jbe@136 374 // if value terminator is not expected here, then return an error:
jbe@136 375 goto json_import_syntax_error;
jbe@121 376 }
jbe@136 377 // consume input character:
jbe@121 378 pos++;
jbe@136 379 // continue with loop:
jbe@121 380 goto json_import_loop;
jbe@136 381 // string literal:
jbe@121 382 case '"':
jbe@146 383 // consume quote character:
jbe@146 384 pos++;
jbe@162 385 // find last character in input string:
jbe@162 386 outlen = pos;
jbe@162 387 while ((c = str[outlen]) != '"') {
jbe@161 388 // consume one character:
jbe@162 389 outlen++;
jbe@161 390 // handle unexpected end of JSON document:
jbe@161 391 if (c == 0) goto json_import_unexpected_eof;
jbe@161 392 // consume one extra character when encountering an escaped quote:
jbe@162 393 else if (c == '\\' && str[outlen] == '"') outlen++;
jbe@161 394 }
jbe@162 395 // determine buffer length:
jbe@162 396 outlen -= pos;
jbe@161 397 // check if string is non empty:
jbe@162 398 if (outlen) {
jbe@161 399 // prepare buffer to decode string (with maximum possible length) and set write position to zero:
jbe@162 400 cbuf = luaL_buffinitsize(L, &luabuf, outlen);
jbe@162 401 outlen = 0;
jbe@161 402 // loop through the characters until encountering end quote:
jbe@161 403 while ((c = str[pos++]) != '"') {
jbe@162 404 // NOTE: unexpected end cannot happen anymore
jbe@162 405 if (c < 32 || c == 127) {
jbe@161 406 // do not allow ASCII control characters:
jbe@161 407 // NOTE: illegal UTF-8 sequences and extended control characters are not sanitized
jbe@161 408 // by this parser to allow different encodings than Unicode
jbe@161 409 lua_pushnil(L);
jbe@161 410 lua_pushliteral(L, "Unexpected control character in JSON string");
jbe@161 411 return 2;
jbe@161 412 } else if (c == '\\') {
jbe@161 413 // read next char after backslash escape:
jbe@161 414 c = str[pos++];
jbe@161 415 switch (c) {
jbe@161 416 // unexpected end-of-string:
jbe@161 417 case 0:
jbe@161 418 goto json_import_unexpected_eof;
jbe@161 419 // unescaping of quotation mark, slash, and backslash:
jbe@161 420 case '"':
jbe@161 421 case '/':
jbe@161 422 case '\\':
jbe@162 423 cbuf[outlen++] = c;
jbe@161 424 break;
jbe@161 425 // unescaping of backspace:
jbe@162 426 case 'b': cbuf[outlen++] = '\b'; break;
jbe@161 427 // unescaping of form-feed:
jbe@162 428 case 'f': cbuf[outlen++] = '\f'; break;
jbe@161 429 // unescaping of new-line:
jbe@162 430 case 'n': cbuf[outlen++] = '\n'; break;
jbe@161 431 // unescaping of carriage-return:
jbe@162 432 case 'r': cbuf[outlen++] = '\r'; break;
jbe@161 433 // unescaping of tabulator:
jbe@162 434 case 't': cbuf[outlen++] = '\t'; break;
jbe@161 435 // unescaping of UTF-16 characters
jbe@161 436 case 'u':
jbe@167 437 // decode 4 hex nibbles:
jbe@167 438 json_import_readhex(codepoint);
jbe@167 439 // handle surrogate character:
jbe@167 440 if (json_utf16_surrogate(codepoint)) {
jbe@167 441 // check if first surrogate is in valid range:
jbe@167 442 if (json_utf16_lead(codepoint)) {
jbe@167 443 // require second surrogate:
jbe@167 444 if ((c = str[pos++]) != '\\' || (c = str[pos++]) != 'u') {
jbe@167 445 if (c == 0) goto json_import_unexpected_eof;
jbe@167 446 else goto json_import_wrong_surrogate;
jbe@167 447 }
jbe@167 448 // read 4 hex nibbles of second surrogate character:
jbe@167 449 json_import_readhex(utf16tail);
jbe@167 450 // check if second surrogate is in valid range:
jbe@167 451 if (!json_utf16_tail(utf16tail)) goto json_import_wrong_surrogate;
jbe@167 452 // calculate codepoint:
jbe@167 453 codepoint = 0x10000 + (utf16tail - 0xDC00) + (codepoint - 0xD800) * 0x400;
jbe@167 454 } else {
jbe@167 455 // throw error for wrong surrogates:
jbe@167 456 json_import_wrong_surrogate:
jbe@167 457 lua_pushnil(L);
jbe@167 458 lua_pushliteral(L, "Illegal UTF-16 surrogate in JSON string escape sequence");
jbe@167 459 return 2;
jbe@167 460 }
jbe@167 461 }
jbe@167 462 // encode as UTF-8:
jbe@167 463 if (codepoint < 0x80) {
jbe@167 464 cbuf[outlen++] = (char)codepoint;
jbe@167 465 } else if (codepoint < 0x800) {
jbe@167 466 cbuf[outlen++] = (char)(0xc0 | (codepoint >> 6));
jbe@167 467 cbuf[outlen++] = (char)(0x80 | (codepoint & 0x3f));
jbe@167 468 } else if (codepoint < 0x10000) {
jbe@167 469 cbuf[outlen++] = (char)(0xe0 | (codepoint >> 12));
jbe@167 470 cbuf[outlen++] = (char)(0x80 | ((codepoint >> 6) & 0x3f));
jbe@167 471 cbuf[outlen++] = (char)(0x80 | (codepoint & 0x3f));
jbe@167 472 } else {
jbe@167 473 cbuf[outlen++] = (char)(0xf0 | (codepoint >> 18));
jbe@167 474 cbuf[outlen++] = (char)(0x80 | ((codepoint >> 12) & 0x3f));
jbe@167 475 cbuf[outlen++] = (char)(0x80 | ((codepoint >> 6) & 0x3f));
jbe@167 476 cbuf[outlen++] = (char)(0x80 | (codepoint & 0x3f));
jbe@167 477 }
jbe@167 478 break;
jbe@161 479 // unexpected escape sequence:
jbe@161 480 default:
jbe@167 481 json_import_unexpected_escape:
jbe@161 482 lua_pushnil(L);
jbe@161 483 lua_pushliteral(L, "Unexpected string escape sequence in JSON document");
jbe@161 484 return 2;
jbe@161 485 }
jbe@161 486 } else {
jbe@161 487 // normal character:
jbe@162 488 cbuf[outlen++] = c;
jbe@121 489 }
jbe@121 490 }
jbe@161 491 // process buffer to Lua string:
jbe@162 492 luaL_pushresultsize(&luabuf, outlen);
jbe@161 493 } else {
jbe@161 494 // if JSON string is empty,
jbe@161 495 // push empty Lua string:
jbe@161 496 lua_pushliteral(L, "");
jbe@167 497 // consume closing quote:
jbe@167 498 pos++;
jbe@121 499 }
jbe@136 500 // continue with processing of decoded string:
jbe@121 501 goto json_import_process_value;
jbe@121 502 }
jbe@136 503 // process values whose type is is not deducible from a single character:
jbe@136 504 if ((c >= '0' && c <= '9') || c == '-' || c == '+') {
jbe@146 505 // for numbers,
jbe@146 506 // use strtod() call to parse a (double precision) floating point number:
jbe@167 507 double numval;
jbe@122 508 char *endptr;
jbe@122 509 numval = strtod(str+pos, &endptr);
jbe@146 510 // catch parsing errors:
jbe@122 511 if (endptr == str+pos) goto json_import_syntax_error;
jbe@146 512 // consume characters that were parsed:
jbe@122 513 pos += endptr - (str+pos);
jbe@146 514 // push parsed (double precision) floating point number on Lua stack:
jbe@122 515 lua_pushnumber(L, numval);
jbe@122 516 } else if (!strncmp(str+pos, "true", 4)) {
jbe@136 517 // consume 4 input characters for "true":
jbe@121 518 pos += 4;
jbe@147 519 // put Lua true value onto stack:
jbe@136 520 lua_pushboolean(L, 1);
jbe@121 521 } else if (!strncmp(str+pos, "false", 5)) {
jbe@136 522 // consume 5 input characters for "false":
jbe@121 523 pos += 5;
jbe@147 524 // put Lua false value onto stack:
jbe@136 525 lua_pushboolean(L, 0);
jbe@121 526 } else if (!strncmp(str+pos, "null", 4)) {
jbe@136 527 // consume 4 input characters for "null":
jbe@136 528 pos += 4;
jbe@153 529 // different behavor for top-level and sub-levels:
jbe@153 530 if (level) {
jbe@153 531 // if sub-level,
jbe@153 532 // push special null-marker onto stack:
jbe@155 533 json_pushnullmark(L);
jbe@153 534 } else {
jbe@153 535 // if top-level,
jbe@153 536 // push nil onto stack:
jbe@153 537 lua_pushnil(L);
jbe@153 538 }
jbe@121 539 } else {
jbe@136 540 // all other cases are a syntax error:
jbe@121 541 goto json_import_syntax_error;
jbe@121 542 }
jbe@136 543 // process a decoded value or key value pair (expected on top of Lua stack):
jbe@136 544 json_import_process_value:
jbe@121 545 switch (mode) {
jbe@136 546 // an object key has been read:
jbe@124 547 case JSON_STATE_OBJECT_KEY:
jbe@136 548 // if an object key is not a string, then this is a syntax error:
jbe@121 549 if (lua_type(L, -1) != LUA_TSTRING) goto json_import_syntax_error;
jbe@146 550 // expect key terminator to follow:
jbe@124 551 mode = JSON_STATE_OBJECT_KEY_TERMINATOR;
jbe@146 552 // continue with loop:
jbe@121 553 goto json_import_loop;
jbe@136 554 // a key value pair has been read:
jbe@124 555 case JSON_STATE_OBJECT_VALUE:
jbe@136 556 // store key value pair in outer shadow table:
jbe@130 557 lua_rawset(L, -3);
jbe@146 558 // expect value terminator (or end of object) to follow:
jbe@124 559 mode = JSON_STATE_OBJECT_SEPARATOR;
jbe@146 560 // continue with loop:
jbe@121 561 goto json_import_loop;
jbe@136 562 // an array value has been read:
jbe@124 563 case JSON_STATE_ARRAY_VALUE:
jbe@152 564 // get current array length:
jbe@152 565 arraylen = lua_rawlen(L, -3);
jbe@152 566 // throw error if array would exceed INT_MAX elements:
jbe@152 567 // TODO: Lua 5.3 may support more elements
jbe@152 568 if (arraylen >= INT_MAX) {
jbe@152 569 lua_pushnil(L);
jbe@152 570 lua_pushfstring(L, "Array exceeded length of %d elements", INT_MAX);
jbe@152 571 }
jbe@136 572 // store value in outer shadow table:
jbe@152 573 lua_rawseti(L, -3, arraylen + 1);
jbe@146 574 // expect value terminator (or end of object) to follow:
jbe@124 575 mode = JSON_STATE_ARRAY_SEPARATOR;
jbe@146 576 // continue with loop
jbe@121 577 goto json_import_loop;
jbe@136 578 // a single value has been read:
jbe@124 579 case JSON_STATE_VALUE:
jbe@136 580 // leave value on top of stack, expect end of JSON document, and continue with loop:
jbe@124 581 mode = JSON_STATE_END;
jbe@121 582 goto json_import_loop;
jbe@121 583 }
jbe@146 584 // syntax error handling (reachable by goto statement):
jbe@136 585 json_import_syntax_error:
jbe@121 586 lua_pushnil(L);
jbe@121 587 lua_pushliteral(L, "Syntax error in JSON document");
jbe@121 588 return 2;
jbe@121 589 }
jbe@121 590
jbe@146 591 // special Lua stack indicies for json_path function:
jbe@138 592 #define json_path_shadowtbl_idx 1
jbe@146 593
jbe@146 594 // stack offset of arguments to json_path function:
jbe@155 595 #define json_path_idxshift 1
jbe@138 596
jbe@146 597 // gets a value or its type from a JSON document (passed as first argument)
jbe@147 598 // using a path (passed as variable number of keys after first argument):
jbe@137 599 static int json_path(lua_State *L, int type_mode) {
jbe@146 600 int stacktop; // stack index of top of stack (after shifting)
jbe@146 601 int idx = 2 + json_path_idxshift; // stack index of current argument to process
jbe@173 602 // require at least one argument:
jbe@173 603 luaL_checkany(L, 1);
jbe@148 604 // insert shadowtbl into stack at position 1 (shifting the arguments):
jbe@144 605 json_regfetch(L, shadowtbl);
jbe@138 606 lua_insert(L, 1);
jbe@146 607 // store stack index of top of stack:
jbe@138 608 stacktop = lua_gettop(L);
jbe@146 609 // use first argument as "current value" (stored on top of stack):
jbe@138 610 lua_pushvalue(L, 1 + json_path_idxshift);
jbe@146 611 // process each "path key" (2nd argument and following arguments):
jbe@138 612 while (idx <= stacktop) {
jbe@146 613 // if "current value" (on top of stack) is nil, then the path cannot be walked and nil is returned:
jbe@137 614 if (lua_isnil(L, -1)) return 1;
jbe@137 615 // try to get shadow table of "current value":
jbe@130 616 lua_pushvalue(L, -1);
jbe@138 617 lua_rawget(L, json_path_shadowtbl_idx);
jbe@126 618 if (lua_isnil(L, -1)) {
jbe@137 619 // if no shadow table is found,
jbe@130 620 if (lua_type(L, -1) == LUA_TTABLE) {
jbe@146 621 // and if "current value" is a table,
jbe@146 622 // drop nil from stack:
jbe@146 623 lua_pop(L, 1);
jbe@137 624 // get "next value" using the "path key":
jbe@130 625 lua_pushvalue(L, idx++);
jbe@130 626 lua_gettable(L, -2);
jbe@130 627 } else {
jbe@137 628 // if "current value" is not a table,
jbe@146 629 // then the path cannot be walked and nil (already on top of stack) is returned:
jbe@137 630 return 1;
jbe@130 631 }
jbe@130 632 } else {
jbe@137 633 // if a shadow table is found,
jbe@137 634 // set "current value" to its shadow table:
jbe@130 635 lua_replace(L, -2);
jbe@137 636 // get "next value" using the "path key":
jbe@130 637 lua_pushvalue(L, idx++);
jbe@130 638 lua_rawget(L, -2);
jbe@126 639 }
jbe@137 640 // the "next value" replaces the "current value":
jbe@130 641 lua_replace(L, -2);
jbe@126 642 }
jbe@137 643 if (!type_mode) {
jbe@137 644 // if a value (and not its type) was requested,
jbe@137 645 // check if value is the null-marker, and store nil on top of Lua stack in that case:
jbe@155 646 if (json_isnullmark(L, -1)) lua_pushnil(L);
jbe@137 647 } else {
jbe@137 648 // if the type was requested,
jbe@137 649 // check if value is the null-marker:
jbe@155 650 if (json_isnullmark(L, -1)) {
jbe@137 651 // if yes, store string "null" on top of Lua stack:
jbe@130 652 lua_pushliteral(L, "null");
jbe@137 653 } else {
jbe@137 654 // otherwise,
jbe@138 655 // check if metatable indicates "object" or "array":
jbe@138 656 if (lua_getmetatable(L, -1)) {
jbe@144 657 json_regfetch(L, objectmt);
jbe@138 658 if (lua_rawequal(L, -2, -1)) {
jbe@146 659 // if value has metatable for JSON objects,
jbe@138 660 // return string "object":
jbe@138 661 lua_pushliteral(L, "object");
jbe@138 662 return 1;
jbe@138 663 }
jbe@144 664 json_regfetch(L, arraymt);
jbe@138 665 if (lua_rawequal(L, -3, -1)) {
jbe@146 666 // if value has metatable for JSON arrays,
jbe@146 667 // return string "object":
jbe@138 668 lua_pushliteral(L, "array");
jbe@138 669 return 1;
jbe@138 670 }
jbe@146 671 // remove 3 metatables (one of the value, two for comparison) from stack:
jbe@138 672 lua_pop(L, 3);
jbe@138 673 }
jbe@138 674 // otherwise, get the Lua type:
jbe@138 675 lua_pushstring(L, lua_typename(L, lua_type(L, -1)));
jbe@126 676 }
jbe@126 677 }
jbe@137 678 // return the top most value on the Lua stack:
jbe@137 679 return 1;
jbe@130 680 }
jbe@130 681
jbe@147 682 // gets a value from a JSON document (passed as first argument)
jbe@147 683 // using a path (passed as variable number of keys after first argument):
jbe@130 684 static int json_get(lua_State *L) {
jbe@137 685 return json_path(L, 0);
jbe@130 686 }
jbe@130 687
jbe@147 688 // gets a value's type from a JSON document (passed as first argument)
jbe@147 689 // using a path (variable number of keys after first argument):
jbe@130 690 static int json_type(lua_State *L) {
jbe@137 691 return json_path(L, 1);
jbe@130 692 }
jbe@130 693
jbe@173 694 // special Lua stack indicies for json_set function:
jbe@173 695 #define json_set_shadowtbl_idx 1
jbe@173 696 #define json_set_objectmt_idx 2
jbe@173 697 #define json_set_arraymt_idx 3
jbe@173 698
jbe@173 699 // stack offset of arguments to json_set function:
jbe@173 700 #define json_set_idxshift 3
jbe@173 701
jbe@173 702 // sets a value (passed as second argument) in a JSON document (passed as first argument)
jbe@173 703 // using a path (variable number of keys starting at third argument):
jbe@173 704 static int json_set(lua_State *L) {
jbe@173 705 int stacktop; // stack index of top of stack (after shifting)
jbe@173 706 int idx = 3; // stack index of current argument to process
jbe@173 707 // require at least two arguments:
jbe@173 708 luaL_checkany(L, 1);
jbe@173 709 luaL_checkany(L, 2);
jbe@173 710 // insert shadowtbl into stack at position 1 (shifting the arguments):
jbe@173 711 json_regfetch(L, shadowtbl);
jbe@173 712 lua_insert(L, 1);
jbe@173 713 // insert objectmt into stack at position 2 (shifting the arguments):
jbe@173 714 json_regfetch(L, objectmt);
jbe@173 715 lua_insert(L, 2);
jbe@173 716 // insert arraymt into stack at position 3 (shifting the arguments):
jbe@173 717 json_regfetch(L, arraymt);
jbe@173 718 lua_insert(L, 3);
jbe@173 719 // store stack index of top of stack:
jbe@173 720 stacktop = lua_gettop(L);
jbe@173 721 // use nil as initial "parent value":
jbe@173 722 lua_pushnil(L);
jbe@173 723 // use first argument as "current value":
jbe@173 724 lua_pushvalue(L, 1 + json_set_idxshift);
jbe@173 725 // set all necessary values in path:
jbe@173 726 for (idx = 3 + json_set_idxshift; idx<=stacktop; idx++) {
jbe@173 727 // push metatable of "current value" onto stack:
jbe@173 728 if (!lua_getmetatable(L, -1)) lua_pushnil(L);
jbe@173 729 // distinguish according to type of path key:
jbe@173 730 switch (lua_type(L, idx)) {
jbe@173 731 case LUA_TSTRING:
jbe@173 732 // if path key is a string,
jbe@173 733 // check if "current value" is a JSON object (or table without metatable):
jbe@173 734 if (
jbe@173 735 lua_rawequal(L, -1, json_set_objectmt_idx) ||
jbe@173 736 (lua_isnil(L, -1) && lua_type(L, -2) == LUA_TTABLE)
jbe@173 737 ) {
jbe@173 738 // if "current value" is acceptable,
jbe@173 739 // pop metatable and leave "current value" on top of stack:
jbe@173 740 lua_pop(L, 1);
jbe@173 741 } else {
jbe@173 742 // if "current value" is not acceptable:
jbe@173 743 // pop metatable and "current value":
jbe@173 744 lua_pop(L, 2);
jbe@173 745 // throw error if parent element does not exist:
jbe@173 746 if (lua_isnil(L, -1)) return luaL_error(L, "Root element is not a JSON object");
jbe@173 747 // push new JSON object as "current value" onto stack:
jbe@173 748 lua_newtable(L);
jbe@173 749 // create and register shadow table:
jbe@173 750 lua_pushvalue(L, -1);
jbe@173 751 lua_newtable(L);
jbe@173 752 lua_rawset(L, json_set_shadowtbl_idx);
jbe@173 753 // set metatable of JSON object:
jbe@173 754 lua_pushvalue(L, json_set_objectmt_idx);
jbe@173 755 lua_setmetatable(L, -2);
jbe@173 756 // set entry in "parent value":
jbe@173 757 lua_pushvalue(L, idx-1);
jbe@173 758 lua_pushvalue(L, -2);
jbe@173 759 lua_settable(L, -4);
jbe@173 760 }
jbe@173 761 break;
jbe@173 762 case LUA_TNUMBER:
jbe@173 763 // if path key is a number,
jbe@173 764 // check if "current value" is a JSON array (or table without metatable):
jbe@173 765 if (
jbe@173 766 lua_rawequal(L, -1, json_set_arraymt_idx) ||
jbe@173 767 (lua_isnil(L, -1) && lua_type(L, -2) == LUA_TTABLE)
jbe@173 768 ) {
jbe@173 769 // if "current value" is acceptable,
jbe@173 770 // pop metatable and leave "current value" on top of stack:
jbe@173 771 lua_pop(L, 1);
jbe@173 772 } else {
jbe@173 773 // if "current value" is not acceptable:
jbe@173 774 // pop metatable and "current value":
jbe@173 775 lua_pop(L, 2);
jbe@173 776 // throw error if parent element does not exist:
jbe@173 777 if (lua_isnil(L, -1)) return luaL_error(L, "Root element is not a JSON array");
jbe@173 778 // push new JSON array as "current value" onto stack:
jbe@173 779 lua_newtable(L);
jbe@173 780 // create and register shadow table:
jbe@173 781 lua_pushvalue(L, -1);
jbe@173 782 lua_newtable(L);
jbe@173 783 lua_rawset(L, json_set_shadowtbl_idx);
jbe@173 784 // set metatable of JSON array:
jbe@173 785 lua_pushvalue(L, json_set_arraymt_idx);
jbe@173 786 lua_setmetatable(L, -2);
jbe@173 787 // set entry in "parent value":
jbe@173 788 lua_pushvalue(L, idx-1);
jbe@173 789 lua_pushvalue(L, -2);
jbe@173 790 lua_settable(L, -4);
jbe@173 791 }
jbe@173 792 break;
jbe@173 793 default:
jbe@173 794 return luaL_error(L, "Invalid path key of type %s", lua_typename(L, lua_type(L, idx)));
jbe@173 795 }
jbe@173 796 // check if last path element is being processed:
jbe@173 797 if (idx == stacktop) {
jbe@173 798 // if the last path element is being processed,
jbe@173 799 // set last path value in "current value" container:
jbe@173 800 lua_pushvalue(L, idx);
jbe@173 801 lua_pushvalue(L, 2 + json_set_idxshift);
jbe@173 802 lua_settable(L, -3);
jbe@173 803 } else {
jbe@173 804 // if the processed path element is not the last,
jbe@173 805 // use old "current value" as new "parent value"
jbe@173 806 lua_remove(L, -2);
jbe@173 807 // push new "current value" onto stack by performing a lookup:
jbe@173 808 lua_pushvalue(L, idx);
jbe@173 809 lua_gettable(L, -2);
jbe@173 810 }
jbe@173 811 }
jbe@173 812 // return first argument for convenience:
jbe@173 813 lua_settop(L, 1 + json_set_idxshift);
jbe@173 814 return 1;
jbe@173 815 }
jbe@173 816
jbe@147 817 // returns the length of a JSON array (or zero for a table without numeric keys):
jbe@130 818 static int json_len(lua_State *L) {
jbe@147 819 // stack shall contain one function argument:
jbe@130 820 lua_settop(L, 1);
jbe@148 821 // try to get corresponding shadow table for first argument:
jbe@144 822 json_regfetch(L, shadowtbl);
jbe@130 823 lua_pushvalue(L, 1);
jbe@138 824 lua_rawget(L, -2);
jbe@147 825 // if shadow table does not exist, return length of argument, else length of shadow table:
jbe@147 826 lua_pushnumber(L, lua_rawlen(L, lua_isnil(L, -1) ? 1 : -1));
jbe@123 827 return 1;
jbe@123 828 }
jbe@123 829
jbe@130 830 static int json_index(lua_State *L) {
jbe@148 831 // stack shall contain two function arguments:
jbe@130 832 lua_settop(L, 2);
jbe@155 833 // get corresponding shadow table for first argument:
jbe@144 834 json_regfetch(L, shadowtbl);
jbe@130 835 lua_pushvalue(L, 1);
jbe@155 836 lua_rawget(L, -2);
jbe@148 837 // throw error if no shadow table was found:
jbe@139 838 if (lua_isnil(L, -1)) return luaL_error(L, "Shadow table not found");
jbe@148 839 // use key passed as second argument to lookup value in shadow table:
jbe@130 840 lua_pushvalue(L, 2);
jbe@130 841 lua_rawget(L, -2);
jbe@148 842 // if value is null-marker, then push nil onto stack:
jbe@155 843 if (json_isnullmark(L, -1)) 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@130 848 static int json_newindex(lua_State *L) {
jbe@148 849 // stack shall contain three function arguments:
jbe@130 850 lua_settop(L, 3);
jbe@148 851 // get corresponding shadow table for first argument:
jbe@144 852 json_regfetch(L, shadowtbl);
jbe@123 853 lua_pushvalue(L, 1);
jbe@143 854 lua_rawget(L, -2);
jbe@148 855 // throw error if no shadow table was found:
jbe@130 856 if (lua_isnil(L, -1)) return luaL_error(L, "Shadow table not found");
jbe@148 857 // replace first argument with shadow table:
jbe@130 858 lua_replace(L, 1);
jbe@148 859 // reset stack and use second and third argument to write to shadow table:
jbe@139 860 lua_settop(L, 3);
jbe@130 861 lua_rawset(L, 1);
jbe@148 862 // return nothing:
jbe@148 863 return 0;
jbe@121 864 }
jbe@121 865
jbe@135 866 static int json_pairs_iterfunc(lua_State *L) {
jbe@149 867 // stack shall contain two function arguments:
jbe@135 868 lua_settop(L, 2);
jbe@155 869 // get corresponding shadow table for first argument:
jbe@144 870 json_regfetch(L, shadowtbl);
jbe@135 871 lua_pushvalue(L, 1);
jbe@155 872 lua_rawget(L, -2);
jbe@149 873 // throw error if no shadow table was found:
jbe@135 874 if (lua_isnil(L, -1)) return luaL_error(L, "Shadow table not found");
jbe@149 875 // get next key value pair from shadow table (using previous key from argument 2)
jbe@149 876 // and return nothing if there is no next pair:
jbe@135 877 lua_pushvalue(L, 2);
jbe@135 878 if (!lua_next(L, -2)) return 0;
jbe@149 879 // replace null-marker with nil:
jbe@155 880 if (json_isnullmark(L, -1)) {
jbe@135 881 lua_pop(L, 1);
jbe@135 882 lua_pushnil(L);
jbe@135 883 }
jbe@149 884 // return key and value (or key and nil, if null-marker was found):
jbe@135 885 return 2;
jbe@135 886 }
jbe@135 887
jbe@149 888 // returns a triple such that 'for key, value in pairs(obj) do ... end'
jbe@149 889 // iterates through all key value pairs (including JSON null keys represented as Lua nil):
jbe@135 890 static int json_pairs(lua_State *L) {
jbe@172 891 // require one argument to function
jbe@172 892 luaL_checkany(L, 1);
jbe@149 893 // return triple of function json_pairs_iterfunc, first argument, and nil:
jbe@139 894 lua_pushcfunction(L, json_pairs_iterfunc);
jbe@135 895 lua_pushvalue(L, 1);
jbe@135 896 lua_pushnil(L);
jbe@135 897 return 3;
jbe@135 898 }
jbe@135 899
jbe@134 900 static int json_ipairs_iterfunc(lua_State *L) {
jbe@152 901 lua_Integer idx;
jbe@149 902 // stack shall contain two function arguments:
jbe@134 903 lua_settop(L, 2);
jbe@149 904 // calculate new index by incrementing second argument:
jbe@134 905 idx = lua_tointeger(L, 2) + 1;
jbe@149 906 // get corresponding shadow table for first argument:
jbe@155 907 json_regfetch(L, shadowtbl);
jbe@134 908 lua_pushvalue(L, 1);
jbe@155 909 lua_rawget(L, -2);
jbe@149 910 // throw error if no shadow table was found:
jbe@134 911 if (lua_isnil(L, -1)) return luaL_error(L, "Shadow table not found");
jbe@149 912 // do integer lookup in shadow table:
jbe@134 913 lua_rawgeti(L, -1, idx);
jbe@149 914 // return nothing if there was no value:
jbe@134 915 if (lua_isnil(L, -1)) return 0;
jbe@149 916 // return new index and
jbe@149 917 // either the looked up value if it is not equal to the null-marker
jbe@149 918 // or nil instead of null-marker:
jbe@134 919 lua_pushinteger(L, idx);
jbe@155 920 if (json_isnullmark(L, -2)) lua_pushnil(L);
jbe@134 921 else lua_pushvalue(L, -2);
jbe@134 922 return 2;
jbe@134 923 }
jbe@134 924
jbe@149 925 // returns a triple such that 'for idx, value in ipairs(ary) do ... end'
jbe@149 926 // iterates through all values (including JSON null represented as Lua nil):
jbe@134 927 static int json_ipairs(lua_State *L) {
jbe@172 928 // require one argument to function
jbe@172 929 luaL_checkany(L, 1);
jbe@149 930 // return triple of function json_ipairs_iterfunc, first argument, and zero:
jbe@139 931 lua_pushcfunction(L, json_ipairs_iterfunc);
jbe@134 932 lua_pushvalue(L, 1);
jbe@134 933 lua_pushinteger(L, 0);
jbe@134 934 return 3;
jbe@134 935 }
jbe@134 936
jbe@163 937 typedef struct {
jbe@163 938 size_t length;
jbe@163 939 const char *data;
jbe@163 940 } json_key_t;
jbe@163 941
jbe@163 942 static int json_key_cmp(json_key_t *key1, json_key_t *key2) {
jbe@163 943 size_t pos = 0;
jbe@163 944 unsigned char c1, c2;
jbe@163 945 while (1) {
jbe@163 946 if (key1->length > pos) {
jbe@163 947 if (key2->length > pos) {
jbe@163 948 c1 = key1->data[pos];
jbe@163 949 c2 = key2->data[pos];
jbe@163 950 if (c1 < c2) return -1;
jbe@163 951 else if (c1 > c2) return 1;
jbe@163 952 } else {
jbe@163 953 return 1;
jbe@163 954 }
jbe@163 955 } else {
jbe@163 956 if (key2->length > pos) {
jbe@163 957 return -1;
jbe@163 958 } else {
jbe@163 959 return 0;
jbe@163 960 }
jbe@163 961 }
jbe@163 962 pos++;
jbe@163 963 }
jbe@163 964 }
jbe@163 965
jbe@154 966 #define JSON_TABLETYPE_UNKNOWN 0
jbe@154 967 #define JSON_TABLETYPE_OBJECT 1
jbe@154 968 #define JSON_TABLETYPE_ARRAY 2
jbe@154 969
jbe@164 970 #define json_export_internal_indentstring_idx 1
jbe@164 971 #define json_export_internal_level_idx 2
jbe@164 972 #define json_export_internal_value_idx 3
jbe@164 973 #define json_export_internal_tmp_idx 4
jbe@164 974
jbe@164 975 static int json_export_internal(lua_State *L) {
jbe@164 976 int level;
jbe@164 977 int pretty;
jbe@164 978 int i;
jbe@154 979 lua_Number num;
jbe@154 980 const char *str;
jbe@154 981 unsigned char c;
jbe@154 982 size_t strlen;
jbe@154 983 size_t pos = 0;
jbe@154 984 luaL_Buffer buf;
jbe@154 985 char hexcode[7]; // backslash, character 'u', 4 hex digits, and terminating NULL byte
jbe@154 986 int tabletype = JSON_TABLETYPE_UNKNOWN;
jbe@164 987 int anyelement = 0;
jbe@163 988 size_t keycount = 0;
jbe@163 989 size_t keypos = 0;
jbe@165 990 json_key_t *keybuf = NULL;
jbe@154 991 lua_Integer idx;
jbe@164 992 lua_settop(L, json_export_internal_value_idx);
jbe@164 993 if (json_isnullmark(L, json_export_internal_value_idx)) {
jbe@164 994 lua_pop(L, 1);
jbe@157 995 lua_pushnil(L);
jbe@157 996 }
jbe@164 997 switch (lua_type(L, json_export_internal_value_idx)) {
jbe@154 998 case LUA_TNIL:
jbe@154 999 lua_pushliteral(L, "null");
jbe@154 1000 return 1;
jbe@154 1001 case LUA_TNUMBER:
jbe@164 1002 num = lua_tonumber(L, json_export_internal_value_idx);
jbe@154 1003 if (isnan(num)) return luaL_error(L, "JSON export not possible for NaN value");
jbe@154 1004 if (isinf(num)) return luaL_error(L, "JSON export not possible for infinite numbers");
jbe@164 1005 lua_tostring(L, json_export_internal_value_idx);
jbe@154 1006 return 1;
jbe@154 1007 case LUA_TBOOLEAN:
jbe@164 1008 if (lua_toboolean(L, json_export_internal_value_idx)) {
jbe@164 1009 lua_pushliteral(L, "true");
jbe@164 1010 } else {
jbe@164 1011 lua_pushliteral(L, "false");
jbe@164 1012 }
jbe@154 1013 return 1;
jbe@154 1014 case LUA_TSTRING:
jbe@164 1015 str = lua_tolstring(L, 3, &strlen);
jbe@154 1016 luaL_buffinit(L, &buf);
jbe@154 1017 luaL_addchar(&buf, '"');
jbe@154 1018 while (pos < strlen) {
jbe@154 1019 c = str[pos++];
jbe@154 1020 if (c == '"') luaL_addstring(&buf, "\\\"");
jbe@154 1021 else if (c == '\\') luaL_addstring(&buf, "\\\\");
jbe@154 1022 else if (c == 127) luaL_addstring(&buf, "\\u007F");
jbe@154 1023 else if (c >= 32) luaL_addchar(&buf, c);
jbe@154 1024 else if (c == '\b') luaL_addstring(&buf, "\\b");
jbe@154 1025 else if (c == '\f') luaL_addstring(&buf, "\\f");
jbe@154 1026 else if (c == '\n') luaL_addstring(&buf, "\\n");
jbe@154 1027 else if (c == '\r') luaL_addstring(&buf, "\\r");
jbe@154 1028 else if (c == '\t') luaL_addstring(&buf, "\\t");
jbe@154 1029 else if (c == '\v') luaL_addstring(&buf, "\\v");
jbe@154 1030 else {
jbe@154 1031 sprintf(hexcode, "\\u%04X", c);
jbe@154 1032 luaL_addstring(&buf, hexcode);
jbe@154 1033 }
jbe@154 1034 }
jbe@154 1035 luaL_addchar(&buf, '"');
jbe@154 1036 luaL_pushresult(&buf);
jbe@154 1037 return 1;
jbe@154 1038 case LUA_TTABLE:
jbe@164 1039 if (lua_getmetatable(L, json_export_internal_value_idx)) {
jbe@154 1040 json_regfetch(L, objectmt);
jbe@154 1041 if (lua_rawequal(L, -2, -1)) {
jbe@154 1042 tabletype = JSON_TABLETYPE_OBJECT;
jbe@154 1043 } else {
jbe@154 1044 json_regfetch(L, arraymt);
jbe@164 1045 if (lua_rawequal(L, -3, -1)) {
jbe@164 1046 tabletype = JSON_TABLETYPE_ARRAY;
jbe@164 1047 } else {
jbe@164 1048 return luaL_error(L, "JSON export not possible for tables with nonsupported metatable");
jbe@164 1049 }
jbe@154 1050 }
jbe@154 1051 }
jbe@154 1052 json_regfetch(L, shadowtbl);
jbe@164 1053 lua_pushvalue(L, json_export_internal_value_idx);
jbe@154 1054 lua_rawget(L, -2);
jbe@164 1055 if (!lua_isnil(L, -1)) lua_replace(L, json_export_internal_value_idx);
jbe@164 1056 lua_settop(L, json_export_internal_value_idx);
jbe@154 1057 if (tabletype == JSON_TABLETYPE_UNKNOWN) {
jbe@164 1058 for (lua_pushnil(L); lua_next(L, json_export_internal_value_idx); lua_pop(L, 1)) {
jbe@164 1059 switch (lua_type(L, -2)) {
jbe@164 1060 case LUA_TSTRING:
jbe@164 1061 keycount++;
jbe@164 1062 if (tabletype == JSON_TABLETYPE_UNKNOWN) tabletype = JSON_TABLETYPE_OBJECT;
jbe@164 1063 else if (tabletype == JSON_TABLETYPE_ARRAY) goto json_export_tabletype_error;
jbe@164 1064 break;
jbe@164 1065 case LUA_TNUMBER:
jbe@164 1066 if (tabletype == JSON_TABLETYPE_UNKNOWN) tabletype = JSON_TABLETYPE_ARRAY;
jbe@164 1067 else if (tabletype == JSON_TABLETYPE_OBJECT) goto json_export_tabletype_error;
jbe@164 1068 break;
jbe@154 1069 }
jbe@154 1070 }
jbe@154 1071 }
jbe@164 1072 pretty = lua_toboolean(L, json_export_internal_indentstring_idx);
jbe@164 1073 level = lua_tointeger(L, json_export_internal_level_idx) + 1;
jbe@164 1074 if (level > JSON_MAXDEPTH) {
jbe@164 1075 return luaL_error(L, "More than %d nested JSON levels", JSON_MAXDEPTH);
jbe@164 1076 }
jbe@154 1077 switch (tabletype) {
jbe@154 1078 case JSON_TABLETYPE_OBJECT:
jbe@164 1079 if (!keycount) {
jbe@164 1080 for (lua_pushnil(L); lua_next(L, json_export_internal_value_idx); lua_pop(L, 1)) {
jbe@164 1081 if (lua_type(L, -2) == LUA_TSTRING) keycount++;
jbe@164 1082 }
jbe@163 1083 }
jbe@163 1084 if (keycount) {
jbe@163 1085 keybuf = calloc(keycount, sizeof(json_key_t));
jbe@163 1086 if (!keybuf) return luaL_error(L, "Memory allocation failed in JSON library");
jbe@164 1087 for (lua_pushnil(L); lua_next(L, json_export_internal_value_idx); lua_pop(L, 1)) {
jbe@163 1088 if (lua_type(L, -2) == LUA_TSTRING) {
jbe@163 1089 json_key_t *key = keybuf + (keypos++);
jbe@163 1090 key->data = lua_tolstring(L, -2, &key->length);
jbe@163 1091 }
jbe@163 1092 }
jbe@163 1093 qsort(keybuf, keycount, sizeof(json_key_t), (void *)json_key_cmp);
jbe@163 1094 }
jbe@154 1095 luaL_buffinit(L, &buf);
jbe@154 1096 luaL_addchar(&buf, '{');
jbe@163 1097 for (keypos=0; keypos<keycount; keypos++) {
jbe@163 1098 json_key_t *key = keybuf + keypos;
jbe@163 1099 if (keypos) luaL_addchar(&buf, ',');
jbe@164 1100 if (pretty) {
jbe@164 1101 luaL_addchar(&buf, '\n');
jbe@164 1102 for (i=0; i<level; i++) {
jbe@164 1103 lua_pushvalue(L, json_export_internal_indentstring_idx);
jbe@164 1104 luaL_addvalue(&buf);
jbe@164 1105 }
jbe@164 1106 }
jbe@164 1107 lua_pushcfunction(L, json_export_internal);
jbe@164 1108 lua_pushvalue(L, json_export_internal_indentstring_idx);
jbe@164 1109 lua_pushinteger(L, level);
jbe@163 1110 lua_pushlstring(L, key->data, key->length);
jbe@164 1111 if (lua_pcall(L, 3, 1, 0)) {
jbe@163 1112 if (keybuf) free(keybuf);
jbe@163 1113 return lua_error(L);
jbe@154 1114 }
jbe@163 1115 luaL_addvalue(&buf);
jbe@163 1116 luaL_addchar(&buf, ':');
jbe@164 1117 if (pretty) luaL_addchar(&buf, ' ');
jbe@164 1118 lua_pushcfunction(L, json_export_internal);
jbe@164 1119 lua_pushvalue(L, json_export_internal_indentstring_idx);
jbe@164 1120 lua_pushinteger(L, level);
jbe@163 1121 lua_pushlstring(L, key->data, key->length);
jbe@164 1122 lua_rawget(L, json_export_internal_value_idx);
jbe@164 1123 if (lua_pcall(L, 3, 1, 0)) {
jbe@163 1124 if (keybuf) free(keybuf);
jbe@163 1125 return lua_error(L);
jbe@163 1126 }
jbe@163 1127 luaL_addvalue(&buf);
jbe@154 1128 }
jbe@163 1129 if (keybuf) free(keybuf);
jbe@164 1130 if (pretty && keycount != 0) {
jbe@164 1131 luaL_addchar(&buf, '\n');
jbe@164 1132 for (i=0; i<level-1; i++) {
jbe@164 1133 lua_pushvalue(L, json_export_internal_indentstring_idx);
jbe@164 1134 luaL_addvalue(&buf);
jbe@164 1135 }
jbe@164 1136 }
jbe@154 1137 luaL_addchar(&buf, '}');
jbe@164 1138 if (pretty && level == 1) luaL_addchar(&buf, '\n');
jbe@154 1139 luaL_pushresult(&buf);
jbe@154 1140 return 1;
jbe@154 1141 case JSON_TABLETYPE_ARRAY:
jbe@164 1142 lua_settop(L, json_export_internal_tmp_idx);
jbe@154 1143 luaL_buffinit(L, &buf);
jbe@154 1144 luaL_addchar(&buf, '[');
jbe@154 1145 for (idx = 1; ; idx++) {
jbe@164 1146 lua_rawgeti(L, json_export_internal_value_idx, idx);
jbe@154 1147 if (lua_isnil(L, -1)) {
jbe@154 1148 lua_pop(L, 1);
jbe@154 1149 break;
jbe@154 1150 }
jbe@164 1151 lua_replace(L, json_export_internal_tmp_idx);
jbe@164 1152 if (anyelement) luaL_addchar(&buf, ',');
jbe@164 1153 anyelement = 1;
jbe@164 1154 if (pretty) {
jbe@164 1155 luaL_addchar(&buf, '\n');
jbe@164 1156 for (i=0; i<level; i++) {
jbe@164 1157 lua_pushvalue(L, json_export_internal_indentstring_idx);
jbe@164 1158 luaL_addvalue(&buf);
jbe@164 1159 }
jbe@164 1160 }
jbe@164 1161 lua_pushcfunction(L, json_export_internal);
jbe@164 1162 lua_pushvalue(L, json_export_internal_indentstring_idx);
jbe@164 1163 lua_pushinteger(L, level);
jbe@164 1164 lua_pushvalue(L, json_export_internal_tmp_idx);
jbe@164 1165 lua_call(L, 3, 1);
jbe@154 1166 luaL_addvalue(&buf);
jbe@154 1167 }
jbe@164 1168 if (pretty && anyelement) {
jbe@164 1169 luaL_addchar(&buf, '\n');
jbe@164 1170 for (i=0; i<level-1; i++) {
jbe@164 1171 lua_pushvalue(L, json_export_internal_indentstring_idx);
jbe@164 1172 luaL_addvalue(&buf);
jbe@164 1173 }
jbe@164 1174 }
jbe@154 1175 luaL_addchar(&buf, ']');
jbe@164 1176 if (pretty && level == 1) luaL_addchar(&buf, '\n');
jbe@154 1177 luaL_pushresult(&buf);
jbe@154 1178 return 1;
jbe@154 1179 }
jbe@154 1180 json_export_tabletype_error:
jbe@154 1181 return luaL_error(L, "JSON export not possible for ambiguous table (cannot decide whether it is an object or array)");
jbe@154 1182 }
jbe@166 1183 return luaL_error(L, "JSON export not possible for values of type \"%s\"", lua_typename(L, lua_type(L, json_export_internal_value_idx)));
jbe@154 1184 }
jbe@154 1185
jbe@164 1186 static int json_export(lua_State *L) {
jbe@164 1187 lua_settop(L, 1);
jbe@164 1188 lua_pushcfunction(L, json_export_internal);
jbe@164 1189 lua_pushnil(L);
jbe@164 1190 lua_pushinteger(L, 0);
jbe@164 1191 lua_pushvalue(L, 1);
jbe@164 1192 lua_call(L, 3, 1);
jbe@164 1193 return 1;
jbe@164 1194 }
jbe@164 1195
jbe@164 1196 static int json_pretty(lua_State *L) {
jbe@164 1197 lua_settop(L, 2);
jbe@164 1198 lua_pushcfunction(L, json_export_internal);
jbe@164 1199 if (lua_isnil(L, 2)) lua_pushliteral(L, " ");
jbe@164 1200 else lua_pushvalue(L, 2);
jbe@164 1201 lua_pushinteger(L, 0);
jbe@164 1202 lua_pushvalue(L, 1);
jbe@164 1203 lua_call(L, 3, 1);
jbe@164 1204 return 1;
jbe@164 1205 }
jbe@164 1206
jbe@149 1207 // functions in library module:
jbe@121 1208 static const struct luaL_Reg json_module_functions[] = {
jbe@133 1209 {"object", json_object},
jbe@173 1210 {"array", json_array},
jbe@121 1211 {"import", json_import},
jbe@154 1212 {"export", json_export},
jbe@164 1213 {"pretty", json_pretty},
jbe@173 1214 {"get", json_get},
jbe@173 1215 {"type", json_type},
jbe@173 1216 {"set", json_set},
jbe@121 1217 {NULL, NULL}
jbe@121 1218 };
jbe@121 1219
jbe@149 1220 // metamethods for JSON objects, JSON arrays, and unknown JSON collections (object or array):
jbe@126 1221 static const struct luaL_Reg json_metatable_functions[] = {
jbe@130 1222 {"__len", json_len},
jbe@130 1223 {"__index", json_index},
jbe@130 1224 {"__newindex", json_newindex},
jbe@135 1225 {"__pairs", json_pairs},
jbe@134 1226 {"__ipairs", json_ipairs},
jbe@160 1227 {"__tostring", json_export},
jbe@126 1228 {NULL, NULL}
jbe@126 1229 };
jbe@126 1230
jbe@157 1231 // metamethods for JSON null marker:
jbe@157 1232 static const struct luaL_Reg json_nullmark_metamethods[] = {
jbe@157 1233 {"__tostring", json_nullmark_tostring},
jbe@157 1234 {NULL, NULL}
jbe@157 1235 };
jbe@157 1236
jbe@149 1237 // initializes json library:
jbe@121 1238 int luaopen_json(lua_State *L) {
jbe@149 1239 // empty stack:
jbe@126 1240 lua_settop(L, 0);
jbe@149 1241 // push library module onto stack position 1:
jbe@149 1242 lua_newtable(L);
jbe@149 1243 // register library functions:
jbe@149 1244 luaL_setfuncs(L, json_module_functions, 0);
jbe@149 1245 // create and store objectmt:
jbe@138 1246 lua_newtable(L);
jbe@138 1247 luaL_setfuncs(L, json_metatable_functions, 0);
jbe@144 1248 json_regstore(L, objectmt);
jbe@149 1249 // create and store arraymt:
jbe@138 1250 lua_newtable(L);
jbe@138 1251 luaL_setfuncs(L, json_metatable_functions, 0);
jbe@144 1252 json_regstore(L, arraymt);
jbe@149 1253 // create and store ephemeron table to store shadow tables for each JSON object/array
jbe@149 1254 // to allow NULL values returned as nil
jbe@149 1255 lua_newtable(L);
jbe@138 1256 lua_newtable(L); // metatable for ephemeron table
jbe@121 1257 lua_pushliteral(L, "__mode");
jbe@121 1258 lua_pushliteral(L, "k");
jbe@138 1259 lua_rawset(L, -3);
jbe@138 1260 lua_setmetatable(L, -2);
jbe@144 1261 json_regstore(L, shadowtbl);
jbe@157 1262 // set metatable of null marker and make it available through library module:
jbe@157 1263 json_pushnullmark(L);
jbe@157 1264 lua_newtable(L);
jbe@157 1265 luaL_setfuncs(L, json_nullmark_metamethods, 0);
jbe@157 1266 lua_setmetatable(L, -2);
jbe@157 1267 lua_setfield(L, 1, "null");
jbe@157 1268 // return library module (that's expected on top of stack):
jbe@121 1269 return 1;
jbe@121 1270 }

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