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annotate libraries/json/json.c @ 175:20e393d2e6e1

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Completed comments and minor code cleanup in JSON library; Added emergency garbage collection for memory allocation in json.export function
author jbe
date Fri Aug 01 21:54:45 2014 +0200 (2014-08-01)
parents 070edea2a92f
children 461e5353ffb1
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@175 51 // converts a Lua table (or any other iterable value) 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@175 103 // throw error if array would exceed INT_MAX elements:
jbe@171 104 // TODO: Lua 5.3 may support more elements
jbe@171 105 if (arrayidx == INT_MAX) {
jbe@171 106 lua_pushnumber(L, (size_t)INT_MAX+1);
jbe@171 107 lua_rawget(L, json_convert_source_idx);
jbe@171 108 if (lua_isnil(L, -1)) break;
jbe@171 109 return luaL_error(L, "Array exceeded length of %d elements", INT_MAX);
jbe@171 110 }
jbe@175 111 // get next array entry:
jbe@171 112 arrayidx++;
jbe@171 113 lua_rawgeti(L, json_convert_source_idx, arrayidx);
jbe@175 114 // break if value is nil:
jbe@171 115 if (lua_isnil(L, -1)) break;
jbe@175 116 // store value in shadow table:
jbe@171 117 lua_rawseti(L, json_convert_shadow_idx, arrayidx);
jbe@171 118 }
jbe@169 119 }
jbe@169 120 } else {
jbe@172 121 // if there is an iterator function,
jbe@172 122 // call iterator function with source value (first argument)
jbe@172 123 // and store 3 result values on stack positions 5 through 7:
jbe@172 124 lua_pushvalue(L, json_convert_iterator_idx);
jbe@172 125 lua_pushvalue(L, 1);
jbe@172 126 lua_call(L, 1, 3);
jbe@175 127 // iterate through key value pairs and store some of them in shadow table
jbe@174 128 // while replacing nil values with null-marker:
jbe@172 129 while (1) {
jbe@175 130 // call iterfun function:
jbe@172 131 lua_pushvalue(L, json_convert_iterfun_idx);
jbe@172 132 lua_pushvalue(L, json_convert_itertbl_idx);
jbe@172 133 lua_pushvalue(L, -3);
jbe@172 134 lua_remove(L, -4);
jbe@172 135 lua_call(L, 2, 2);
jbe@175 136 // break iteration loop if key is nil:
jbe@172 137 if (lua_isnil(L, -2)) break;
jbe@175 138 // store key value pair only if key type is correct:
jbe@172 139 if (lua_type(L, -2) == (array ? LUA_TNUMBER : LUA_TSTRING)) {
jbe@175 140 // if key type is correct,
jbe@175 141 // push key onto stack:
jbe@172 142 lua_pushvalue(L, -2);
jbe@175 143 // if value is nil, push null-marker onto stack (as value):
jbe@174 144 if (lua_isnil(L, -2)) json_pushnullmark(L);
jbe@175 145 // else push value onto stack:
jbe@174 146 else lua_pushvalue(L, -2);
jbe@175 147 // set key value pair in shadow table:
jbe@172 148 lua_rawset(L, json_convert_shadow_idx);
jbe@172 149 }
jbe@175 150 // pop value from stack, but leave key on stack:
jbe@172 151 lua_pop(L, 1);
jbe@172 152 }
jbe@143 153 }
jbe@171 154 // let result table be on top of stack:
jbe@169 155 lua_settop(L, json_convert_output_idx);
jbe@136 156 }
jbe@171 157 // set metatable (for result table on top of stack):
jbe@171 158 if (array == 0) json_regfetch(L, objectmt);
jbe@171 159 else json_regfetch(L, arraymt);
jbe@169 160 lua_setmetatable(L, -2);
jbe@171 161 // return table on top of stack:
jbe@136 162 return 1;
jbe@136 163 }
jbe@136 164
jbe@175 165 // converts a Lua table (or any other iterable value) to a JSON object:
jbe@175 166 // (does never modify the argument, returns an empty object or array if argument is nil)
jbe@136 167 static int json_object(lua_State *L) {
jbe@169 168 return json_convert(L, 0);
jbe@136 169 }
jbe@136 170
jbe@175 171 // converts a Lua table (or any other iterable value) to a JSON array:
jbe@175 172 // (does never modify the argument, returns an empty object or array if argument is nil)
jbe@136 173 static int json_array(lua_State *L) {
jbe@169 174 return json_convert(L, 1);
jbe@136 175 }
jbe@136 176
jbe@145 177 // internal states of JSON parser:
jbe@124 178 #define JSON_STATE_VALUE 0
jbe@124 179 #define JSON_STATE_OBJECT_KEY 1
jbe@124 180 #define JSON_STATE_OBJECT_KEY_TERMINATOR 2
jbe@124 181 #define JSON_STATE_OBJECT_VALUE 3
jbe@124 182 #define JSON_STATE_OBJECT_SEPARATOR 4
jbe@124 183 #define JSON_STATE_ARRAY_VALUE 5
jbe@124 184 #define JSON_STATE_ARRAY_SEPARATOR 6
jbe@124 185 #define JSON_STATE_END 7
jbe@121 186
jbe@145 187 // special Lua stack indicies for json_import function:
jbe@138 188 #define json_import_objectmt_idx 2
jbe@138 189 #define json_import_arraymt_idx 3
jbe@138 190 #define json_import_shadowtbl_idx 4
jbe@138 191
jbe@168 192 // macros for hex decoding:
jbe@168 193 #define json_utf16_surrogate(x) ((x) >= 0xD800 && (x) <= 0xDFFF)
jbe@168 194 #define json_utf16_lead(x) ((x) >= 0xD800 && (x) <= 0xDBFF)
jbe@168 195 #define json_utf16_tail(x) ((x) >= 0xDC00 && (x) <= 0xDFFF)
jbe@167 196 #define json_import_readhex(x) \
jbe@167 197 do { \
jbe@167 198 x = 0; \
jbe@167 199 for (i=0; i<4; i++) { \
jbe@167 200 x <<= 4; \
jbe@167 201 c = str[pos++]; \
jbe@167 202 if (c >= '0' && c <= '9') x += c - '0'; \
jbe@167 203 else if (c >= 'A' && c <= 'F') x += c - 'A' + 10; \
jbe@167 204 else if (c >= 'a' && c <= 'f') x += c - 'a' + 10; \
jbe@167 205 else if (c == 0) goto json_import_unexpected_eof; \
jbe@167 206 else goto json_import_unexpected_escape; \
jbe@167 207 } \
jbe@167 208 } while (0)
jbe@167 209
jbe@136 210 // decodes a JSON document:
jbe@121 211 static int json_import(lua_State *L) {
jbe@167 212 int i; // loop variable
jbe@136 213 const char *str; // string to parse
jbe@136 214 size_t total; // total length of string to parse
jbe@136 215 size_t pos = 0; // current position in string to parse
jbe@136 216 size_t level = 0; // nested levels of objects/arrays currently being processed
jbe@145 217 int mode = JSON_STATE_VALUE; // state of parser (i.e. "what's expected next?")
jbe@170 218 unsigned char c; // variable to store a single character to be processed (unsigned!)
jbe@145 219 luaL_Buffer luabuf; // Lua buffer to decode JSON string values
jbe@145 220 char *cbuf; // C buffer to decode JSON string values
jbe@162 221 size_t outlen; // maximum length or write position of C buffer
jbe@167 222 long codepoint; // decoded UTF-16 character or higher codepoint
jbe@167 223 long utf16tail; // second decoded UTF-16 character (surrogate tail)
jbe@152 224 size_t arraylen; // variable to temporarily store the array length
jbe@166 225 // require string as argument and convert to C string with length information:
jbe@166 226 str = luaL_checklstring(L, 1, &total);
jbe@166 227 // if string contains a NULL byte, this is a syntax error
jbe@166 228 if (strlen(str) != total) goto json_import_syntax_error;
jbe@147 229 // stack shall contain one function argument:
jbe@138 230 lua_settop(L, 1);
jbe@147 231 // push objectmt onto stack position 2:
jbe@144 232 json_regfetch(L, objectmt);
jbe@147 233 // push arraymt onto stack position 3:
jbe@144 234 json_regfetch(L, arraymt);
jbe@147 235 // push shadowtbl onto stack position 4:
jbe@144 236 json_regfetch(L, shadowtbl);
jbe@136 237 // main loop of parser:
jbe@136 238 json_import_loop:
jbe@136 239 // skip whitespace and store next character in variable 'c':
jbe@146 240 while (c = str[pos],
jbe@146 241 c == ' ' ||
jbe@146 242 c == '\f' ||
jbe@146 243 c == '\n' ||
jbe@146 244 c == '\r' ||
jbe@146 245 c == '\t' ||
jbe@146 246 c == '\v'
jbe@146 247 ) pos++;
jbe@170 248 // NOTE: variable c needs to be unsigned in the following code
jbe@136 249 // switch statement to handle certain (single) characters:
jbe@121 250 switch (c) {
jbe@136 251 // handle end of JSON document:
jbe@121 252 case 0:
jbe@136 253 // if end of JSON document was expected, then return top element of stack as result:
jbe@124 254 if (mode == JSON_STATE_END) return 1;
jbe@136 255 // otherwise, the JSON document was malformed:
jbe@167 256 if (level == 0) {
jbe@167 257 lua_pushnil(L);
jbe@167 258 lua_pushliteral(L, "Empty string");
jbe@167 259 } else {
jbe@167 260 json_import_unexpected_eof:
jbe@167 261 lua_pushnil(L);
jbe@167 262 lua_pushliteral(L, "Unexpected end of JSON document");
jbe@167 263 }
jbe@121 264 return 2;
jbe@136 265 // new JSON object:
jbe@121 266 case '{':
jbe@136 267 // if a JSON object is not expected here, then return an error:
jbe@146 268 if (
jbe@146 269 mode != JSON_STATE_VALUE &&
jbe@146 270 mode != JSON_STATE_OBJECT_VALUE &&
jbe@146 271 mode != JSON_STATE_ARRAY_VALUE
jbe@146 272 ) goto json_import_syntax_error;
jbe@136 273 // create JSON object on stack:
jbe@136 274 lua_newtable(L);
jbe@136 275 // set metatable of JSON object:
jbe@138 276 lua_pushvalue(L, json_import_objectmt_idx);
jbe@125 277 lua_setmetatable(L, -2);
jbe@136 278 // create internal shadow table on stack:
jbe@136 279 lua_newtable(L);
jbe@146 280 // register internal shadow table:
jbe@123 281 lua_pushvalue(L, -2);
jbe@123 282 lua_pushvalue(L, -2);
jbe@138 283 lua_rawset(L, json_import_shadowtbl_idx);
jbe@146 284 // expect object key (or end of object) to follow:
jbe@136 285 mode = JSON_STATE_OBJECT_KEY;
jbe@146 286 // jump to common code for opening JSON object and JSON array:
jbe@142 287 goto json_import_open;
jbe@136 288 // new JSON array:
jbe@121 289 case '[':
jbe@136 290 // if a JSON array is not expected here, then return an error:
jbe@146 291 if (
jbe@146 292 mode != JSON_STATE_VALUE &&
jbe@146 293 mode != JSON_STATE_OBJECT_VALUE &&
jbe@146 294 mode != JSON_STATE_ARRAY_VALUE
jbe@146 295 ) goto json_import_syntax_error;
jbe@136 296 // create JSON array on stack:
jbe@136 297 lua_newtable(L);
jbe@136 298 // set metatable of JSON array:
jbe@138 299 lua_pushvalue(L, json_import_arraymt_idx);
jbe@125 300 lua_setmetatable(L, -2);
jbe@136 301 // create internal shadow table on stack:
jbe@136 302 lua_newtable(L);
jbe@146 303 // register internal shadow table:
jbe@123 304 lua_pushvalue(L, -2);
jbe@123 305 lua_pushvalue(L, -2);
jbe@138 306 lua_rawset(L, json_import_shadowtbl_idx);
jbe@140 307 // add nil as key (needed to keep stack balance) and as magic to detect arrays:
jbe@140 308 lua_pushnil(L);
jbe@146 309 // expect array value (or end of array) to follow:
jbe@142 310 mode = JSON_STATE_ARRAY_VALUE;
jbe@142 311 // continue with common code for opening JSON object and JSON array:
jbe@146 312 // common code for opening JSON object or JSON array:
jbe@142 313 json_import_open:
jbe@142 314 // limit nested levels:
jbe@142 315 if (level >= JSON_MAXDEPTH) {
jbe@142 316 lua_pushnil(L);
jbe@164 317 lua_pushfstring(L, "More than %d nested JSON levels", JSON_MAXDEPTH);
jbe@142 318 return 2;
jbe@142 319 }
jbe@142 320 // additional buffer overflow protection:
jbe@142 321 if (!lua_checkstack(L, LUA_MINSTACK))
jbe@142 322 return luaL_error(L, "Caught stack overflow in JSON import function (too many nested levels and stack size too small)");
jbe@136 323 // increment level:
jbe@121 324 level++;
jbe@142 325 // consume input character:
jbe@142 326 pos++;
jbe@121 327 goto json_import_loop;
jbe@136 328 // end of JSON object:
jbe@121 329 case '}':
jbe@136 330 // if end of JSON object is not expected here, then return an error:
jbe@146 331 if (
jbe@146 332 mode != JSON_STATE_OBJECT_KEY &&
jbe@146 333 mode != JSON_STATE_OBJECT_SEPARATOR
jbe@146 334 ) goto json_import_syntax_error;
jbe@136 335 // jump to common code for end of JSON object and JSON array:
jbe@121 336 goto json_import_close;
jbe@136 337 // end of JSON array:
jbe@121 338 case ']':
jbe@136 339 // if end of JSON array is not expected here, then return an error:
jbe@146 340 if (
jbe@146 341 mode != JSON_STATE_ARRAY_VALUE &&
jbe@146 342 mode != JSON_STATE_ARRAY_SEPARATOR
jbe@146 343 ) goto json_import_syntax_error;
jbe@146 344 // pop nil key/magic (that was needed to keep stack balance):
jbe@140 345 lua_pop(L, 1);
jbe@136 346 // continue with common code for end of JSON object and JSON array:
jbe@136 347 // common code for end of JSON object or JSON array:
jbe@121 348 json_import_close:
jbe@136 349 // consume input character:
jbe@121 350 pos++;
jbe@136 351 // pop shadow table:
jbe@136 352 lua_pop(L, 1);
jbe@136 353 // check if nested:
jbe@121 354 if (--level) {
jbe@146 355 // if nested,
jbe@146 356 // check if outer(!) structure is an array or object:
jbe@140 357 if (lua_isnil(L, -2)) {
jbe@136 358 // select array value processing:
jbe@124 359 mode = JSON_STATE_ARRAY_VALUE;
jbe@121 360 } else {
jbe@136 361 // select object value processing:
jbe@124 362 mode = JSON_STATE_OBJECT_VALUE;
jbe@121 363 }
jbe@136 364 // store value in outer structure:
jbe@121 365 goto json_import_process_value;
jbe@121 366 }
jbe@136 367 // if not nested, then expect end of JSON document and continue with loop:
jbe@136 368 mode = JSON_STATE_END;
jbe@121 369 goto json_import_loop;
jbe@136 370 // key terminator:
jbe@121 371 case ':':
jbe@136 372 // if key terminator is not expected here, then return an error:
jbe@124 373 if (mode != JSON_STATE_OBJECT_KEY_TERMINATOR)
jbe@121 374 goto json_import_syntax_error;
jbe@136 375 // consume input character:
jbe@121 376 pos++;
jbe@146 377 // expect object value to follow:
jbe@124 378 mode = JSON_STATE_OBJECT_VALUE;
jbe@146 379 // continue with loop:
jbe@121 380 goto json_import_loop;
jbe@136 381 // value terminator (NOTE: trailing comma at end of value or key-value list is tolerated by this parser)
jbe@121 382 case ',':
jbe@146 383 // branch according to parser state:
jbe@124 384 if (mode == JSON_STATE_OBJECT_SEPARATOR) {
jbe@146 385 // expect an object key to follow:
jbe@124 386 mode = JSON_STATE_OBJECT_KEY;
jbe@124 387 } else if (mode == JSON_STATE_ARRAY_SEPARATOR) {
jbe@146 388 // expect an array value to follow:
jbe@124 389 mode = JSON_STATE_ARRAY_VALUE;
jbe@121 390 } else {
jbe@136 391 // if value terminator is not expected here, then return an error:
jbe@136 392 goto json_import_syntax_error;
jbe@121 393 }
jbe@136 394 // consume input character:
jbe@121 395 pos++;
jbe@136 396 // continue with loop:
jbe@121 397 goto json_import_loop;
jbe@136 398 // string literal:
jbe@121 399 case '"':
jbe@146 400 // consume quote character:
jbe@146 401 pos++;
jbe@162 402 // find last character in input string:
jbe@162 403 outlen = pos;
jbe@162 404 while ((c = str[outlen]) != '"') {
jbe@161 405 // consume one character:
jbe@162 406 outlen++;
jbe@161 407 // handle unexpected end of JSON document:
jbe@161 408 if (c == 0) goto json_import_unexpected_eof;
jbe@161 409 // consume one extra character when encountering an escaped quote:
jbe@162 410 else if (c == '\\' && str[outlen] == '"') outlen++;
jbe@161 411 }
jbe@162 412 // determine buffer length:
jbe@162 413 outlen -= pos;
jbe@161 414 // check if string is non empty:
jbe@162 415 if (outlen) {
jbe@161 416 // prepare buffer to decode string (with maximum possible length) and set write position to zero:
jbe@162 417 cbuf = luaL_buffinitsize(L, &luabuf, outlen);
jbe@162 418 outlen = 0;
jbe@161 419 // loop through the characters until encountering end quote:
jbe@161 420 while ((c = str[pos++]) != '"') {
jbe@162 421 // NOTE: unexpected end cannot happen anymore
jbe@162 422 if (c < 32 || c == 127) {
jbe@161 423 // do not allow ASCII control characters:
jbe@161 424 // NOTE: illegal UTF-8 sequences and extended control characters are not sanitized
jbe@161 425 // by this parser to allow different encodings than Unicode
jbe@161 426 lua_pushnil(L);
jbe@161 427 lua_pushliteral(L, "Unexpected control character in JSON string");
jbe@161 428 return 2;
jbe@161 429 } else if (c == '\\') {
jbe@161 430 // read next char after backslash escape:
jbe@161 431 c = str[pos++];
jbe@161 432 switch (c) {
jbe@161 433 // unexpected end-of-string:
jbe@161 434 case 0:
jbe@161 435 goto json_import_unexpected_eof;
jbe@161 436 // unescaping of quotation mark, slash, and backslash:
jbe@161 437 case '"':
jbe@161 438 case '/':
jbe@161 439 case '\\':
jbe@162 440 cbuf[outlen++] = c;
jbe@161 441 break;
jbe@161 442 // unescaping of backspace:
jbe@162 443 case 'b': cbuf[outlen++] = '\b'; break;
jbe@161 444 // unescaping of form-feed:
jbe@162 445 case 'f': cbuf[outlen++] = '\f'; break;
jbe@161 446 // unescaping of new-line:
jbe@162 447 case 'n': cbuf[outlen++] = '\n'; break;
jbe@161 448 // unescaping of carriage-return:
jbe@162 449 case 'r': cbuf[outlen++] = '\r'; break;
jbe@161 450 // unescaping of tabulator:
jbe@162 451 case 't': cbuf[outlen++] = '\t'; break;
jbe@161 452 // unescaping of UTF-16 characters
jbe@161 453 case 'u':
jbe@167 454 // decode 4 hex nibbles:
jbe@167 455 json_import_readhex(codepoint);
jbe@167 456 // handle surrogate character:
jbe@167 457 if (json_utf16_surrogate(codepoint)) {
jbe@167 458 // check if first surrogate is in valid range:
jbe@167 459 if (json_utf16_lead(codepoint)) {
jbe@167 460 // require second surrogate:
jbe@167 461 if ((c = str[pos++]) != '\\' || (c = str[pos++]) != 'u') {
jbe@167 462 if (c == 0) goto json_import_unexpected_eof;
jbe@167 463 else goto json_import_wrong_surrogate;
jbe@167 464 }
jbe@167 465 // read 4 hex nibbles of second surrogate character:
jbe@167 466 json_import_readhex(utf16tail);
jbe@167 467 // check if second surrogate is in valid range:
jbe@167 468 if (!json_utf16_tail(utf16tail)) goto json_import_wrong_surrogate;
jbe@167 469 // calculate codepoint:
jbe@167 470 codepoint = 0x10000 + (utf16tail - 0xDC00) + (codepoint - 0xD800) * 0x400;
jbe@167 471 } else {
jbe@167 472 // throw error for wrong surrogates:
jbe@167 473 json_import_wrong_surrogate:
jbe@167 474 lua_pushnil(L);
jbe@167 475 lua_pushliteral(L, "Illegal UTF-16 surrogate in JSON string escape sequence");
jbe@167 476 return 2;
jbe@167 477 }
jbe@167 478 }
jbe@167 479 // encode as UTF-8:
jbe@167 480 if (codepoint < 0x80) {
jbe@167 481 cbuf[outlen++] = (char)codepoint;
jbe@167 482 } else if (codepoint < 0x800) {
jbe@167 483 cbuf[outlen++] = (char)(0xc0 | (codepoint >> 6));
jbe@167 484 cbuf[outlen++] = (char)(0x80 | (codepoint & 0x3f));
jbe@167 485 } else if (codepoint < 0x10000) {
jbe@167 486 cbuf[outlen++] = (char)(0xe0 | (codepoint >> 12));
jbe@167 487 cbuf[outlen++] = (char)(0x80 | ((codepoint >> 6) & 0x3f));
jbe@167 488 cbuf[outlen++] = (char)(0x80 | (codepoint & 0x3f));
jbe@167 489 } else {
jbe@167 490 cbuf[outlen++] = (char)(0xf0 | (codepoint >> 18));
jbe@167 491 cbuf[outlen++] = (char)(0x80 | ((codepoint >> 12) & 0x3f));
jbe@167 492 cbuf[outlen++] = (char)(0x80 | ((codepoint >> 6) & 0x3f));
jbe@167 493 cbuf[outlen++] = (char)(0x80 | (codepoint & 0x3f));
jbe@167 494 }
jbe@167 495 break;
jbe@161 496 // unexpected escape sequence:
jbe@161 497 default:
jbe@167 498 json_import_unexpected_escape:
jbe@161 499 lua_pushnil(L);
jbe@161 500 lua_pushliteral(L, "Unexpected string escape sequence in JSON document");
jbe@161 501 return 2;
jbe@161 502 }
jbe@161 503 } else {
jbe@161 504 // normal character:
jbe@162 505 cbuf[outlen++] = c;
jbe@121 506 }
jbe@121 507 }
jbe@161 508 // process buffer to Lua string:
jbe@162 509 luaL_pushresultsize(&luabuf, outlen);
jbe@161 510 } else {
jbe@161 511 // if JSON string is empty,
jbe@161 512 // push empty Lua string:
jbe@161 513 lua_pushliteral(L, "");
jbe@167 514 // consume closing quote:
jbe@167 515 pos++;
jbe@121 516 }
jbe@136 517 // continue with processing of decoded string:
jbe@121 518 goto json_import_process_value;
jbe@121 519 }
jbe@136 520 // process values whose type is is not deducible from a single character:
jbe@136 521 if ((c >= '0' && c <= '9') || c == '-' || c == '+') {
jbe@146 522 // for numbers,
jbe@146 523 // use strtod() call to parse a (double precision) floating point number:
jbe@167 524 double numval;
jbe@122 525 char *endptr;
jbe@122 526 numval = strtod(str+pos, &endptr);
jbe@146 527 // catch parsing errors:
jbe@122 528 if (endptr == str+pos) goto json_import_syntax_error;
jbe@146 529 // consume characters that were parsed:
jbe@122 530 pos += endptr - (str+pos);
jbe@146 531 // push parsed (double precision) floating point number on Lua stack:
jbe@122 532 lua_pushnumber(L, numval);
jbe@122 533 } else if (!strncmp(str+pos, "true", 4)) {
jbe@136 534 // consume 4 input characters for "true":
jbe@121 535 pos += 4;
jbe@147 536 // put Lua true value onto stack:
jbe@136 537 lua_pushboolean(L, 1);
jbe@121 538 } else if (!strncmp(str+pos, "false", 5)) {
jbe@136 539 // consume 5 input characters for "false":
jbe@121 540 pos += 5;
jbe@147 541 // put Lua false value onto stack:
jbe@136 542 lua_pushboolean(L, 0);
jbe@121 543 } else if (!strncmp(str+pos, "null", 4)) {
jbe@136 544 // consume 4 input characters for "null":
jbe@136 545 pos += 4;
jbe@153 546 // different behavor for top-level and sub-levels:
jbe@153 547 if (level) {
jbe@153 548 // if sub-level,
jbe@153 549 // push special null-marker onto stack:
jbe@155 550 json_pushnullmark(L);
jbe@153 551 } else {
jbe@153 552 // if top-level,
jbe@153 553 // push nil onto stack:
jbe@153 554 lua_pushnil(L);
jbe@153 555 }
jbe@121 556 } else {
jbe@136 557 // all other cases are a syntax error:
jbe@121 558 goto json_import_syntax_error;
jbe@121 559 }
jbe@136 560 // process a decoded value or key value pair (expected on top of Lua stack):
jbe@136 561 json_import_process_value:
jbe@121 562 switch (mode) {
jbe@136 563 // an object key has been read:
jbe@124 564 case JSON_STATE_OBJECT_KEY:
jbe@136 565 // if an object key is not a string, then this is a syntax error:
jbe@121 566 if (lua_type(L, -1) != LUA_TSTRING) goto json_import_syntax_error;
jbe@146 567 // expect key terminator to follow:
jbe@124 568 mode = JSON_STATE_OBJECT_KEY_TERMINATOR;
jbe@146 569 // continue with loop:
jbe@121 570 goto json_import_loop;
jbe@136 571 // a key value pair has been read:
jbe@124 572 case JSON_STATE_OBJECT_VALUE:
jbe@136 573 // store key value pair in outer shadow table:
jbe@130 574 lua_rawset(L, -3);
jbe@146 575 // expect value terminator (or end of object) to follow:
jbe@124 576 mode = JSON_STATE_OBJECT_SEPARATOR;
jbe@146 577 // continue with loop:
jbe@121 578 goto json_import_loop;
jbe@136 579 // an array value has been read:
jbe@124 580 case JSON_STATE_ARRAY_VALUE:
jbe@152 581 // get current array length:
jbe@152 582 arraylen = lua_rawlen(L, -3);
jbe@152 583 // throw error if array would exceed INT_MAX elements:
jbe@152 584 // TODO: Lua 5.3 may support more elements
jbe@152 585 if (arraylen >= INT_MAX) {
jbe@152 586 lua_pushnil(L);
jbe@152 587 lua_pushfstring(L, "Array exceeded length of %d elements", INT_MAX);
jbe@152 588 }
jbe@136 589 // store value in outer shadow table:
jbe@152 590 lua_rawseti(L, -3, arraylen + 1);
jbe@146 591 // expect value terminator (or end of object) to follow:
jbe@124 592 mode = JSON_STATE_ARRAY_SEPARATOR;
jbe@146 593 // continue with loop
jbe@121 594 goto json_import_loop;
jbe@136 595 // a single value has been read:
jbe@124 596 case JSON_STATE_VALUE:
jbe@136 597 // leave value on top of stack, expect end of JSON document, and continue with loop:
jbe@124 598 mode = JSON_STATE_END;
jbe@121 599 goto json_import_loop;
jbe@121 600 }
jbe@146 601 // syntax error handling (reachable by goto statement):
jbe@136 602 json_import_syntax_error:
jbe@121 603 lua_pushnil(L);
jbe@121 604 lua_pushliteral(L, "Syntax error in JSON document");
jbe@121 605 return 2;
jbe@121 606 }
jbe@121 607
jbe@146 608 // special Lua stack indicies for json_path function:
jbe@138 609 #define json_path_shadowtbl_idx 1
jbe@146 610
jbe@146 611 // stack offset of arguments to json_path function:
jbe@155 612 #define json_path_idxshift 1
jbe@138 613
jbe@146 614 // gets a value or its type from a JSON document (passed as first argument)
jbe@175 615 // using a path (passed as variable number of keys after the first argument):
jbe@137 616 static int json_path(lua_State *L, int type_mode) {
jbe@146 617 int stacktop; // stack index of top of stack (after shifting)
jbe@146 618 int idx = 2 + json_path_idxshift; // stack index of current argument to process
jbe@173 619 // require at least one argument:
jbe@173 620 luaL_checkany(L, 1);
jbe@148 621 // insert shadowtbl into stack at position 1 (shifting the arguments):
jbe@144 622 json_regfetch(L, shadowtbl);
jbe@138 623 lua_insert(L, 1);
jbe@146 624 // store stack index of top of stack:
jbe@138 625 stacktop = lua_gettop(L);
jbe@146 626 // use first argument as "current value" (stored on top of stack):
jbe@138 627 lua_pushvalue(L, 1 + json_path_idxshift);
jbe@146 628 // process each "path key" (2nd argument and following arguments):
jbe@138 629 while (idx <= stacktop) {
jbe@146 630 // if "current value" (on top of stack) is nil, then the path cannot be walked and nil is returned:
jbe@137 631 if (lua_isnil(L, -1)) return 1;
jbe@137 632 // try to get shadow table of "current value":
jbe@130 633 lua_pushvalue(L, -1);
jbe@138 634 lua_rawget(L, json_path_shadowtbl_idx);
jbe@126 635 if (lua_isnil(L, -1)) {
jbe@137 636 // if no shadow table is found,
jbe@130 637 if (lua_type(L, -1) == LUA_TTABLE) {
jbe@146 638 // and if "current value" is a table,
jbe@146 639 // drop nil from stack:
jbe@146 640 lua_pop(L, 1);
jbe@137 641 // get "next value" using the "path key":
jbe@130 642 lua_pushvalue(L, idx++);
jbe@130 643 lua_gettable(L, -2);
jbe@130 644 } else {
jbe@137 645 // if "current value" is not a table,
jbe@146 646 // then the path cannot be walked and nil (already on top of stack) is returned:
jbe@137 647 return 1;
jbe@130 648 }
jbe@130 649 } else {
jbe@137 650 // if a shadow table is found,
jbe@137 651 // set "current value" to its shadow table:
jbe@130 652 lua_replace(L, -2);
jbe@137 653 // get "next value" using the "path key":
jbe@130 654 lua_pushvalue(L, idx++);
jbe@130 655 lua_rawget(L, -2);
jbe@126 656 }
jbe@137 657 // the "next value" replaces the "current value":
jbe@130 658 lua_replace(L, -2);
jbe@126 659 }
jbe@137 660 if (!type_mode) {
jbe@137 661 // if a value (and not its type) was requested,
jbe@137 662 // check if value is the null-marker, and store nil on top of Lua stack in that case:
jbe@155 663 if (json_isnullmark(L, -1)) lua_pushnil(L);
jbe@137 664 } else {
jbe@137 665 // if the type was requested,
jbe@137 666 // check if value is the null-marker:
jbe@155 667 if (json_isnullmark(L, -1)) {
jbe@137 668 // if yes, store string "null" on top of Lua stack:
jbe@130 669 lua_pushliteral(L, "null");
jbe@137 670 } else {
jbe@137 671 // otherwise,
jbe@138 672 // check if metatable indicates "object" or "array":
jbe@138 673 if (lua_getmetatable(L, -1)) {
jbe@144 674 json_regfetch(L, objectmt);
jbe@138 675 if (lua_rawequal(L, -2, -1)) {
jbe@146 676 // if value has metatable for JSON objects,
jbe@138 677 // return string "object":
jbe@138 678 lua_pushliteral(L, "object");
jbe@138 679 return 1;
jbe@138 680 }
jbe@144 681 json_regfetch(L, arraymt);
jbe@138 682 if (lua_rawequal(L, -3, -1)) {
jbe@146 683 // if value has metatable for JSON arrays,
jbe@146 684 // return string "object":
jbe@138 685 lua_pushliteral(L, "array");
jbe@138 686 return 1;
jbe@138 687 }
jbe@146 688 // remove 3 metatables (one of the value, two for comparison) from stack:
jbe@138 689 lua_pop(L, 3);
jbe@138 690 }
jbe@138 691 // otherwise, get the Lua type:
jbe@138 692 lua_pushstring(L, lua_typename(L, lua_type(L, -1)));
jbe@126 693 }
jbe@126 694 }
jbe@137 695 // return the top most value on the Lua stack:
jbe@137 696 return 1;
jbe@130 697 }
jbe@130 698
jbe@147 699 // gets a value from a JSON document (passed as first argument)
jbe@175 700 // using a path (passed as variable number of keys after the first argument):
jbe@130 701 static int json_get(lua_State *L) {
jbe@137 702 return json_path(L, 0);
jbe@130 703 }
jbe@130 704
jbe@147 705 // gets a value's type from a JSON document (passed as first argument)
jbe@175 706 // using a path (passed as variable number of keys after first the argument):
jbe@130 707 static int json_type(lua_State *L) {
jbe@137 708 return json_path(L, 1);
jbe@130 709 }
jbe@130 710
jbe@173 711 // special Lua stack indicies for json_set function:
jbe@173 712 #define json_set_shadowtbl_idx 1
jbe@173 713 #define json_set_objectmt_idx 2
jbe@173 714 #define json_set_arraymt_idx 3
jbe@173 715
jbe@173 716 // stack offset of arguments to json_set function:
jbe@173 717 #define json_set_idxshift 3
jbe@173 718
jbe@173 719 // sets a value (passed as second argument) in a JSON document (passed as first argument)
jbe@175 720 // using a path (passed as variable number of keys starting at third argument):
jbe@173 721 static int json_set(lua_State *L) {
jbe@173 722 int stacktop; // stack index of top of stack (after shifting)
jbe@173 723 int idx = 3; // stack index of current argument to process
jbe@173 724 // require at least two arguments:
jbe@173 725 luaL_checkany(L, 1);
jbe@173 726 luaL_checkany(L, 2);
jbe@173 727 // insert shadowtbl into stack at position 1 (shifting the arguments):
jbe@173 728 json_regfetch(L, shadowtbl);
jbe@173 729 lua_insert(L, 1);
jbe@173 730 // insert objectmt into stack at position 2 (shifting the arguments):
jbe@173 731 json_regfetch(L, objectmt);
jbe@173 732 lua_insert(L, 2);
jbe@173 733 // insert arraymt into stack at position 3 (shifting the arguments):
jbe@173 734 json_regfetch(L, arraymt);
jbe@173 735 lua_insert(L, 3);
jbe@173 736 // store stack index of top of stack:
jbe@173 737 stacktop = lua_gettop(L);
jbe@173 738 // use nil as initial "parent value":
jbe@173 739 lua_pushnil(L);
jbe@173 740 // use first argument as "current value":
jbe@173 741 lua_pushvalue(L, 1 + json_set_idxshift);
jbe@173 742 // set all necessary values in path:
jbe@173 743 for (idx = 3 + json_set_idxshift; idx<=stacktop; idx++) {
jbe@173 744 // push metatable of "current value" onto stack:
jbe@173 745 if (!lua_getmetatable(L, -1)) lua_pushnil(L);
jbe@173 746 // distinguish according to type of path key:
jbe@173 747 switch (lua_type(L, idx)) {
jbe@173 748 case LUA_TSTRING:
jbe@173 749 // if path key is a string,
jbe@173 750 // check if "current value" is a JSON object (or table without metatable):
jbe@173 751 if (
jbe@173 752 lua_rawequal(L, -1, json_set_objectmt_idx) ||
jbe@173 753 (lua_isnil(L, -1) && lua_type(L, -2) == LUA_TTABLE)
jbe@173 754 ) {
jbe@173 755 // if "current value" is acceptable,
jbe@173 756 // pop metatable and leave "current value" on top of stack:
jbe@173 757 lua_pop(L, 1);
jbe@173 758 } else {
jbe@173 759 // if "current value" is not acceptable:
jbe@173 760 // pop metatable and "current value":
jbe@173 761 lua_pop(L, 2);
jbe@173 762 // throw error if parent element does not exist:
jbe@173 763 if (lua_isnil(L, -1)) return luaL_error(L, "Root element is not a JSON object");
jbe@173 764 // push new JSON object as "current value" onto stack:
jbe@173 765 lua_newtable(L);
jbe@173 766 // create and register shadow table:
jbe@173 767 lua_pushvalue(L, -1);
jbe@173 768 lua_newtable(L);
jbe@173 769 lua_rawset(L, json_set_shadowtbl_idx);
jbe@173 770 // set metatable of JSON object:
jbe@173 771 lua_pushvalue(L, json_set_objectmt_idx);
jbe@173 772 lua_setmetatable(L, -2);
jbe@173 773 // set entry in "parent value":
jbe@173 774 lua_pushvalue(L, idx-1);
jbe@173 775 lua_pushvalue(L, -2);
jbe@173 776 lua_settable(L, -4);
jbe@173 777 }
jbe@173 778 break;
jbe@173 779 case LUA_TNUMBER:
jbe@173 780 // if path key is a number,
jbe@173 781 // check if "current value" is a JSON array (or table without metatable):
jbe@173 782 if (
jbe@173 783 lua_rawequal(L, -1, json_set_arraymt_idx) ||
jbe@173 784 (lua_isnil(L, -1) && lua_type(L, -2) == LUA_TTABLE)
jbe@173 785 ) {
jbe@173 786 // if "current value" is acceptable,
jbe@173 787 // pop metatable and leave "current value" on top of stack:
jbe@173 788 lua_pop(L, 1);
jbe@173 789 } else {
jbe@173 790 // if "current value" is not acceptable:
jbe@173 791 // pop metatable and "current value":
jbe@173 792 lua_pop(L, 2);
jbe@173 793 // throw error if parent element does not exist:
jbe@173 794 if (lua_isnil(L, -1)) return luaL_error(L, "Root element is not a JSON array");
jbe@173 795 // push new JSON array as "current value" onto stack:
jbe@173 796 lua_newtable(L);
jbe@173 797 // create and register shadow table:
jbe@173 798 lua_pushvalue(L, -1);
jbe@173 799 lua_newtable(L);
jbe@173 800 lua_rawset(L, json_set_shadowtbl_idx);
jbe@173 801 // set metatable of JSON array:
jbe@173 802 lua_pushvalue(L, json_set_arraymt_idx);
jbe@173 803 lua_setmetatable(L, -2);
jbe@173 804 // set entry in "parent value":
jbe@173 805 lua_pushvalue(L, idx-1);
jbe@173 806 lua_pushvalue(L, -2);
jbe@173 807 lua_settable(L, -4);
jbe@173 808 }
jbe@173 809 break;
jbe@173 810 default:
jbe@173 811 return luaL_error(L, "Invalid path key of type %s", lua_typename(L, lua_type(L, idx)));
jbe@173 812 }
jbe@173 813 // check if last path element is being processed:
jbe@173 814 if (idx == stacktop) {
jbe@173 815 // if the last path element is being processed,
jbe@173 816 // set last path value in "current value" container:
jbe@173 817 lua_pushvalue(L, idx);
jbe@173 818 lua_pushvalue(L, 2 + json_set_idxshift);
jbe@173 819 lua_settable(L, -3);
jbe@173 820 } else {
jbe@173 821 // if the processed path element is not the last,
jbe@173 822 // use old "current value" as new "parent value"
jbe@173 823 lua_remove(L, -2);
jbe@173 824 // push new "current value" onto stack by performing a lookup:
jbe@173 825 lua_pushvalue(L, idx);
jbe@173 826 lua_gettable(L, -2);
jbe@173 827 }
jbe@173 828 }
jbe@173 829 // return first argument for convenience:
jbe@173 830 lua_settop(L, 1 + json_set_idxshift);
jbe@173 831 return 1;
jbe@173 832 }
jbe@173 833
jbe@147 834 // returns the length of a JSON array (or zero for a table without numeric keys):
jbe@130 835 static int json_len(lua_State *L) {
jbe@147 836 // stack shall contain one function argument:
jbe@130 837 lua_settop(L, 1);
jbe@148 838 // try to get corresponding shadow table for first argument:
jbe@144 839 json_regfetch(L, shadowtbl);
jbe@130 840 lua_pushvalue(L, 1);
jbe@138 841 lua_rawget(L, -2);
jbe@147 842 // if shadow table does not exist, return length of argument, else length of shadow table:
jbe@147 843 lua_pushnumber(L, lua_rawlen(L, lua_isnil(L, -1) ? 1 : -1));
jbe@123 844 return 1;
jbe@123 845 }
jbe@123 846
jbe@175 847 // __index metamethod for JSON objects and JSON arrays:
jbe@130 848 static int json_index(lua_State *L) {
jbe@148 849 // stack shall contain two function arguments:
jbe@130 850 lua_settop(L, 2);
jbe@155 851 // get corresponding shadow table for first argument:
jbe@144 852 json_regfetch(L, shadowtbl);
jbe@130 853 lua_pushvalue(L, 1);
jbe@155 854 lua_rawget(L, -2);
jbe@148 855 // throw error if no shadow table was found:
jbe@139 856 if (lua_isnil(L, -1)) return luaL_error(L, "Shadow table not found");
jbe@148 857 // use key passed as second argument to lookup value in shadow table:
jbe@130 858 lua_pushvalue(L, 2);
jbe@130 859 lua_rawget(L, -2);
jbe@148 860 // if value is null-marker, then push nil onto stack:
jbe@155 861 if (json_isnullmark(L, -1)) lua_pushnil(L);
jbe@148 862 // return either looked up value, or nil
jbe@127 863 return 1;
jbe@127 864 }
jbe@127 865
jbe@175 866 // __newindex metamethod for JSON objects and JSON arrays:
jbe@130 867 static int json_newindex(lua_State *L) {
jbe@148 868 // stack shall contain three function arguments:
jbe@130 869 lua_settop(L, 3);
jbe@148 870 // get corresponding shadow table for first argument:
jbe@144 871 json_regfetch(L, shadowtbl);
jbe@123 872 lua_pushvalue(L, 1);
jbe@143 873 lua_rawget(L, -2);
jbe@148 874 // throw error if no shadow table was found:
jbe@130 875 if (lua_isnil(L, -1)) return luaL_error(L, "Shadow table not found");
jbe@148 876 // replace first argument with shadow table:
jbe@130 877 lua_replace(L, 1);
jbe@148 878 // reset stack and use second and third argument to write to shadow table:
jbe@139 879 lua_settop(L, 3);
jbe@130 880 lua_rawset(L, 1);
jbe@148 881 // return nothing:
jbe@148 882 return 0;
jbe@121 883 }
jbe@121 884
jbe@175 885 // function returned as first value by json_pairs function:
jbe@135 886 static int json_pairs_iterfunc(lua_State *L) {
jbe@149 887 // stack shall contain two function arguments:
jbe@135 888 lua_settop(L, 2);
jbe@155 889 // get corresponding shadow table for first argument:
jbe@144 890 json_regfetch(L, shadowtbl);
jbe@135 891 lua_pushvalue(L, 1);
jbe@155 892 lua_rawget(L, -2);
jbe@149 893 // throw error if no shadow table was found:
jbe@135 894 if (lua_isnil(L, -1)) return luaL_error(L, "Shadow table not found");
jbe@149 895 // get next key value pair from shadow table (using previous key from argument 2)
jbe@149 896 // and return nothing if there is no next pair:
jbe@135 897 lua_pushvalue(L, 2);
jbe@135 898 if (!lua_next(L, -2)) return 0;
jbe@149 899 // replace null-marker with nil:
jbe@155 900 if (json_isnullmark(L, -1)) {
jbe@135 901 lua_pop(L, 1);
jbe@135 902 lua_pushnil(L);
jbe@135 903 }
jbe@149 904 // return key and value (or key and nil, if null-marker was found):
jbe@135 905 return 2;
jbe@135 906 }
jbe@135 907
jbe@149 908 // returns a triple such that 'for key, value in pairs(obj) do ... end'
jbe@175 909 // iterates through all key value pairs (including JSON null values represented as Lua nil):
jbe@135 910 static int json_pairs(lua_State *L) {
jbe@172 911 // require one argument to function
jbe@172 912 luaL_checkany(L, 1);
jbe@149 913 // return triple of function json_pairs_iterfunc, first argument, and nil:
jbe@139 914 lua_pushcfunction(L, json_pairs_iterfunc);
jbe@135 915 lua_pushvalue(L, 1);
jbe@135 916 lua_pushnil(L);
jbe@135 917 return 3;
jbe@135 918 }
jbe@135 919
jbe@175 920 // function returned as first value by json_ipairs function:
jbe@134 921 static int json_ipairs_iterfunc(lua_State *L) {
jbe@152 922 lua_Integer idx;
jbe@149 923 // stack shall contain two function arguments:
jbe@134 924 lua_settop(L, 2);
jbe@149 925 // calculate new index by incrementing second argument:
jbe@134 926 idx = lua_tointeger(L, 2) + 1;
jbe@149 927 // get corresponding shadow table for first argument:
jbe@155 928 json_regfetch(L, shadowtbl);
jbe@134 929 lua_pushvalue(L, 1);
jbe@155 930 lua_rawget(L, -2);
jbe@149 931 // throw error if no shadow table was found:
jbe@134 932 if (lua_isnil(L, -1)) return luaL_error(L, "Shadow table not found");
jbe@149 933 // do integer lookup in shadow table:
jbe@134 934 lua_rawgeti(L, -1, idx);
jbe@149 935 // return nothing if there was no value:
jbe@134 936 if (lua_isnil(L, -1)) return 0;
jbe@149 937 // return new index and
jbe@149 938 // either the looked up value if it is not equal to the null-marker
jbe@149 939 // or nil instead of null-marker:
jbe@134 940 lua_pushinteger(L, idx);
jbe@155 941 if (json_isnullmark(L, -2)) lua_pushnil(L);
jbe@134 942 else lua_pushvalue(L, -2);
jbe@134 943 return 2;
jbe@134 944 }
jbe@134 945
jbe@149 946 // returns a triple such that 'for idx, value in ipairs(ary) do ... end'
jbe@175 947 // iterates through all values (including JSON null values represented as Lua nil):
jbe@134 948 static int json_ipairs(lua_State *L) {
jbe@172 949 // require one argument to function
jbe@172 950 luaL_checkany(L, 1);
jbe@149 951 // return triple of function json_ipairs_iterfunc, first argument, and zero:
jbe@139 952 lua_pushcfunction(L, json_ipairs_iterfunc);
jbe@134 953 lua_pushvalue(L, 1);
jbe@134 954 lua_pushinteger(L, 0);
jbe@134 955 return 3;
jbe@134 956 }
jbe@134 957
jbe@175 958 // datatype representing a table key:
jbe@175 959 // (used for sorting)
jbe@163 960 typedef struct {
jbe@163 961 size_t length;
jbe@163 962 const char *data;
jbe@163 963 } json_key_t;
jbe@163 964
jbe@175 965 // comparation function for table keys to be passed to qsort function:
jbe@163 966 static int json_key_cmp(json_key_t *key1, json_key_t *key2) {
jbe@163 967 size_t pos = 0;
jbe@163 968 unsigned char c1, c2;
jbe@163 969 while (1) {
jbe@163 970 if (key1->length > pos) {
jbe@163 971 if (key2->length > pos) {
jbe@163 972 c1 = key1->data[pos];
jbe@163 973 c2 = key2->data[pos];
jbe@163 974 if (c1 < c2) return -1;
jbe@163 975 else if (c1 > c2) return 1;
jbe@163 976 } else {
jbe@163 977 return 1;
jbe@163 978 }
jbe@163 979 } else {
jbe@163 980 if (key2->length > pos) {
jbe@163 981 return -1;
jbe@163 982 } else {
jbe@163 983 return 0;
jbe@163 984 }
jbe@163 985 }
jbe@163 986 pos++;
jbe@163 987 }
jbe@163 988 }
jbe@163 989
jbe@175 990 // constants for type detection of ambiguous tables:
jbe@154 991 #define JSON_TABLETYPE_UNKNOWN 0
jbe@154 992 #define JSON_TABLETYPE_OBJECT 1
jbe@154 993 #define JSON_TABLETYPE_ARRAY 2
jbe@154 994
jbe@175 995 // special Lua stack indicies for json_export_internal function:
jbe@164 996 #define json_export_internal_indentstring_idx 1
jbe@164 997 #define json_export_internal_level_idx 2
jbe@164 998 #define json_export_internal_value_idx 3
jbe@164 999 #define json_export_internal_tmp_idx 4
jbe@164 1000
jbe@175 1001 // encodes a JSON document (passed as third argument)
jbe@175 1002 // optionally using indentation (indentation string passed as first argument)
jbe@175 1003 // for a certain depth level (passed as second argument):
jbe@164 1004 static int json_export_internal(lua_State *L) {
jbe@175 1005 int level; // current depth level
jbe@175 1006 int pretty; // pretty printing on? (i.e. printing with indentation)
jbe@175 1007 int i; // iteration variable for level dependent repetitions:
jbe@175 1008 lua_Number num; // number to encode
jbe@175 1009 const char *str; // string to encode
jbe@175 1010 size_t strlen; // length of string to encode
jbe@175 1011 unsigned char c; // character to encode (unsigned!)
jbe@175 1012 size_t pos = 0; // position in string or position of current key (initialized with zero!)
jbe@175 1013 luaL_Buffer buf; // Lua buffer to create strings
jbe@175 1014 char hexcode[7]; // store for unicode hex escape sequence
jbe@175 1015 // NOTE: 7 bytes due to backslash, character 'u', 4 hex digits, and terminating NULL byte
jbe@175 1016 int tabletype = JSON_TABLETYPE_UNKNOWN; // table type: unknown, JSON object, or JSON array
jbe@175 1017 int anyelement = 0; // set to 1 if at least one array element has been processed
jbe@175 1018 size_t keycount = 0; // number of string keys in object
jbe@175 1019 json_key_t *keybuf = NULL; // temporary buffer to store (and sort) string keys of objects
jbe@175 1020 lua_Integer arrayidx; // index to iterate through arrays
jbe@175 1021 // stack shall contain three function arguments:
jbe@164 1022 lua_settop(L, json_export_internal_value_idx);
jbe@175 1023 // if value to encode is the null-marker, then treat it the same as nil:
jbe@164 1024 if (json_isnullmark(L, json_export_internal_value_idx)) {
jbe@164 1025 lua_pop(L, 1);
jbe@157 1026 lua_pushnil(L);
jbe@157 1027 }
jbe@175 1028 // distinguish between different Lua types:
jbe@164 1029 switch (lua_type(L, json_export_internal_value_idx)) {
jbe@175 1030 // value to encode is nil:
jbe@154 1031 case LUA_TNIL:
jbe@175 1032 // return string "null":
jbe@154 1033 lua_pushliteral(L, "null");
jbe@154 1034 return 1;
jbe@175 1035 // value to encode is of type number:
jbe@154 1036 case LUA_TNUMBER:
jbe@175 1037 // convert value to double precision number:
jbe@164 1038 num = lua_tonumber(L, json_export_internal_value_idx);
jbe@175 1039 // throw error if number is not-a-number:
jbe@154 1040 if (isnan(num)) return luaL_error(L, "JSON export not possible for NaN value");
jbe@175 1041 // throw error if number is positive or negative infinity:
jbe@154 1042 if (isinf(num)) return luaL_error(L, "JSON export not possible for infinite numbers");
jbe@175 1043 // return Lua's string encoding of the number:
jbe@164 1044 lua_tostring(L, json_export_internal_value_idx);
jbe@154 1045 return 1;
jbe@175 1046 // value to encode is of type boolean:
jbe@154 1047 case LUA_TBOOLEAN:
jbe@175 1048 // return string "true" or "false" according to boolean value:
jbe@164 1049 if (lua_toboolean(L, json_export_internal_value_idx)) {
jbe@164 1050 lua_pushliteral(L, "true");
jbe@164 1051 } else {
jbe@164 1052 lua_pushliteral(L, "false");
jbe@164 1053 }
jbe@154 1054 return 1;
jbe@175 1055 // value to encode is of type string:
jbe@154 1056 case LUA_TSTRING:
jbe@175 1057 // quote, escape and return string:
jbe@164 1058 str = lua_tolstring(L, 3, &strlen);
jbe@154 1059 luaL_buffinit(L, &buf);
jbe@154 1060 luaL_addchar(&buf, '"');
jbe@154 1061 while (pos < strlen) {
jbe@154 1062 c = str[pos++];
jbe@154 1063 if (c == '"') luaL_addstring(&buf, "\\\"");
jbe@154 1064 else if (c == '\\') luaL_addstring(&buf, "\\\\");
jbe@154 1065 else if (c == 127) luaL_addstring(&buf, "\\u007F");
jbe@154 1066 else if (c >= 32) luaL_addchar(&buf, c);
jbe@154 1067 else if (c == '\b') luaL_addstring(&buf, "\\b");
jbe@154 1068 else if (c == '\f') luaL_addstring(&buf, "\\f");
jbe@154 1069 else if (c == '\n') luaL_addstring(&buf, "\\n");
jbe@154 1070 else if (c == '\r') luaL_addstring(&buf, "\\r");
jbe@154 1071 else if (c == '\t') luaL_addstring(&buf, "\\t");
jbe@154 1072 else if (c == '\v') luaL_addstring(&buf, "\\v");
jbe@154 1073 else {
jbe@154 1074 sprintf(hexcode, "\\u%04X", c);
jbe@154 1075 luaL_addstring(&buf, hexcode);
jbe@154 1076 }
jbe@154 1077 }
jbe@154 1078 luaL_addchar(&buf, '"');
jbe@154 1079 luaL_pushresult(&buf);
jbe@154 1080 return 1;
jbe@175 1081 // value to encode is of type table (this includes JSON objects and JSON arrays):
jbe@154 1082 case LUA_TTABLE:
jbe@175 1083 // use table's metatable to try to determine type of table:
jbe@164 1084 if (lua_getmetatable(L, json_export_internal_value_idx)) {
jbe@154 1085 json_regfetch(L, objectmt);
jbe@154 1086 if (lua_rawequal(L, -2, -1)) {
jbe@154 1087 tabletype = JSON_TABLETYPE_OBJECT;
jbe@154 1088 } else {
jbe@154 1089 json_regfetch(L, arraymt);
jbe@164 1090 if (lua_rawequal(L, -3, -1)) {
jbe@164 1091 tabletype = JSON_TABLETYPE_ARRAY;
jbe@164 1092 } else {
jbe@164 1093 return luaL_error(L, "JSON export not possible for tables with nonsupported metatable");
jbe@164 1094 }
jbe@154 1095 }
jbe@154 1096 }
jbe@175 1097 // replace table with its shadow table if existent, and reset stack:
jbe@154 1098 json_regfetch(L, shadowtbl);
jbe@164 1099 lua_pushvalue(L, json_export_internal_value_idx);
jbe@154 1100 lua_rawget(L, -2);
jbe@164 1101 if (!lua_isnil(L, -1)) lua_replace(L, json_export_internal_value_idx);
jbe@164 1102 lua_settop(L, json_export_internal_value_idx);
jbe@175 1103 // check if type of table is still undetermined:
jbe@154 1104 if (tabletype == JSON_TABLETYPE_UNKNOWN) {
jbe@175 1105 // if yes, iterate over all keys:
jbe@164 1106 for (lua_pushnil(L); lua_next(L, json_export_internal_value_idx); lua_pop(L, 1)) {
jbe@164 1107 switch (lua_type(L, -2)) {
jbe@164 1108 case LUA_TSTRING:
jbe@175 1109 // for string keys,
jbe@175 1110 // increase keycount (may avoid another iteration):
jbe@164 1111 keycount++;
jbe@175 1112 // if type of table was unknown, then type of table is a JSON object now:
jbe@164 1113 if (tabletype == JSON_TABLETYPE_UNKNOWN) tabletype = JSON_TABLETYPE_OBJECT;
jbe@175 1114 // if type of table was a JSON array, then the type of table is ambiguous now
jbe@175 1115 // and an error is thrown:
jbe@164 1116 else if (tabletype == JSON_TABLETYPE_ARRAY) goto json_export_tabletype_error;
jbe@164 1117 break;
jbe@164 1118 case LUA_TNUMBER:
jbe@175 1119 // for numeric keys,
jbe@175 1120 // if type of table was unknown, then type of table is a JSON array now:
jbe@164 1121 if (tabletype == JSON_TABLETYPE_UNKNOWN) tabletype = JSON_TABLETYPE_ARRAY;
jbe@175 1122 // if type of table was a JSON object, then the type of table is ambiguous now
jbe@175 1123 // and an error is thrown:
jbe@164 1124 else if (tabletype == JSON_TABLETYPE_OBJECT) goto json_export_tabletype_error;
jbe@164 1125 break;
jbe@154 1126 }
jbe@154 1127 }
jbe@154 1128 }
jbe@175 1129 // set pretty variable to 1 if pretty printing (with indentation) is desired:
jbe@164 1130 pretty = lua_toboolean(L, json_export_internal_indentstring_idx);
jbe@175 1131 // set level variable to corresponding function argument increased by one:
jbe@164 1132 level = lua_tointeger(L, json_export_internal_level_idx) + 1;
jbe@175 1133 // throw error if there are more levels that could be imported by this library:
jbe@164 1134 if (level > JSON_MAXDEPTH) {
jbe@164 1135 return luaL_error(L, "More than %d nested JSON levels", JSON_MAXDEPTH);
jbe@164 1136 }
jbe@175 1137 // distinguish between JSON objects and JSON arrays:
jbe@154 1138 switch (tabletype) {
jbe@175 1139 // JSON object:
jbe@154 1140 case JSON_TABLETYPE_OBJECT:
jbe@175 1141 // calculate count of string keys unless it has been calculated before:
jbe@164 1142 if (!keycount) {
jbe@164 1143 for (lua_pushnil(L); lua_next(L, json_export_internal_value_idx); lua_pop(L, 1)) {
jbe@164 1144 if (lua_type(L, -2) == LUA_TSTRING) keycount++;
jbe@164 1145 }
jbe@163 1146 }
jbe@175 1147 // create a sorted list of all string keys in memory:
jbe@163 1148 if (keycount) {
jbe@175 1149 // allocate memory for string keys:
jbe@163 1150 keybuf = calloc(keycount, sizeof(json_key_t));
jbe@175 1151 // check if memory allocation was successful:
jbe@175 1152 if (!keybuf) {
jbe@175 1153 // in case of memory exhaustion, try to collect garbage:
jbe@175 1154 lua_gc(L, LUA_GCCOLLECT, 0);
jbe@175 1155 // try to allocate memory again:
jbe@175 1156 keybuf = calloc(keycount, sizeof(json_key_t));
jbe@175 1157 // throw error if memory allocation failed again:
jbe@175 1158 if (!keybuf) {
jbe@175 1159 return luaL_error(L, "Memory allocation failed in JSON library");
jbe@175 1160 }
jbe@175 1161 }
jbe@175 1162 // copy all string keys to the C array:
jbe@164 1163 for (lua_pushnil(L); lua_next(L, json_export_internal_value_idx); lua_pop(L, 1)) {
jbe@163 1164 if (lua_type(L, -2) == LUA_TSTRING) {
jbe@175 1165 json_key_t *key = keybuf + (pos++);
jbe@163 1166 key->data = lua_tolstring(L, -2, &key->length);
jbe@163 1167 }
jbe@163 1168 }
jbe@175 1169 // sort C array using quicksort:
jbe@163 1170 qsort(keybuf, keycount, sizeof(json_key_t), (void *)json_key_cmp);
jbe@163 1171 }
jbe@175 1172 // create Lua string buffer:
jbe@154 1173 luaL_buffinit(L, &buf);
jbe@175 1174 // add opening bracket to output buffer:
jbe@154 1175 luaL_addchar(&buf, '{');
jbe@175 1176 // iterate through all (sorted) string keys:
jbe@175 1177 for (pos=0; pos<keycount; pos++) {
jbe@175 1178 json_key_t *key = keybuf + pos;
jbe@175 1179 // add comma to output buffer unless we process the first key:
jbe@175 1180 if (pos) luaL_addchar(&buf, ',');
jbe@175 1181 // handle indentation for pretty results:
jbe@164 1182 if (pretty) {
jbe@164 1183 luaL_addchar(&buf, '\n');
jbe@164 1184 for (i=0; i<level; i++) {
jbe@164 1185 lua_pushvalue(L, json_export_internal_indentstring_idx);
jbe@164 1186 luaL_addvalue(&buf);
jbe@164 1187 }
jbe@164 1188 }
jbe@175 1189 // recursive call to encode key:
jbe@164 1190 lua_pushcfunction(L, json_export_internal);
jbe@164 1191 lua_pushvalue(L, json_export_internal_indentstring_idx);
jbe@164 1192 lua_pushinteger(L, level);
jbe@163 1193 lua_pushlstring(L, key->data, key->length);
jbe@164 1194 if (lua_pcall(L, 3, 1, 0)) {
jbe@175 1195 // free memory of sorted string keys on error:
jbe@163 1196 if (keybuf) free(keybuf);
jbe@175 1197 // rethrow error:
jbe@163 1198 return lua_error(L);
jbe@154 1199 }
jbe@175 1200 // add encoded key to output buffer:
jbe@163 1201 luaL_addvalue(&buf);
jbe@175 1202 // add colon to output buffer:
jbe@163 1203 luaL_addchar(&buf, ':');
jbe@175 1204 // handle indentation for pretty results:
jbe@164 1205 if (pretty) luaL_addchar(&buf, ' ');
jbe@175 1206 // recursive call to encode value:
jbe@164 1207 lua_pushcfunction(L, json_export_internal);
jbe@164 1208 lua_pushvalue(L, json_export_internal_indentstring_idx);
jbe@164 1209 lua_pushinteger(L, level);
jbe@163 1210 lua_pushlstring(L, key->data, key->length);
jbe@164 1211 lua_rawget(L, json_export_internal_value_idx);
jbe@164 1212 if (lua_pcall(L, 3, 1, 0)) {
jbe@175 1213 // free memory of sorted string keys on error:
jbe@163 1214 if (keybuf) free(keybuf);
jbe@175 1215 // rethrow error:
jbe@163 1216 return lua_error(L);
jbe@163 1217 }
jbe@175 1218 // add encoded value to output buffer:
jbe@163 1219 luaL_addvalue(&buf);
jbe@154 1220 }
jbe@175 1221 // decrement level variable for all following statements:
jbe@175 1222 level--;
jbe@175 1223 // free memory of sorted string keys:
jbe@163 1224 if (keybuf) free(keybuf);
jbe@175 1225 // handle indentation for pretty results:
jbe@164 1226 if (pretty && keycount != 0) {
jbe@164 1227 luaL_addchar(&buf, '\n');
jbe@175 1228 for (i=0; i<level; i++) {
jbe@164 1229 lua_pushvalue(L, json_export_internal_indentstring_idx);
jbe@164 1230 luaL_addvalue(&buf);
jbe@164 1231 }
jbe@164 1232 }
jbe@175 1233 // add closing bracket to output buffer:
jbe@154 1234 luaL_addchar(&buf, '}');
jbe@175 1235 // for pretty results, add final newline character if outermost container is processed:
jbe@175 1236 if (pretty && level == 0) luaL_addchar(&buf, '\n');
jbe@175 1237 // convert and return buffer:
jbe@154 1238 luaL_pushresult(&buf);
jbe@154 1239 return 1;
jbe@175 1240 // JSON array:
jbe@154 1241 case JSON_TABLETYPE_ARRAY:
jbe@175 1242 // reserve an extra element on the stack (needed because Lua buffer has unknown size on stack):
jbe@164 1243 lua_settop(L, json_export_internal_tmp_idx);
jbe@175 1244 // create Lua string buffer:
jbe@154 1245 luaL_buffinit(L, &buf);
jbe@175 1246 // add opening bracket to output buffer:
jbe@154 1247 luaL_addchar(&buf, '[');
jbe@175 1248 // iterate through integer keys:
jbe@175 1249 for (arrayidx = 1; ; arrayidx++) {
jbe@175 1250 // get value in array, and break if nil:
jbe@175 1251 lua_rawgeti(L, json_export_internal_value_idx, arrayidx);
jbe@154 1252 if (lua_isnil(L, -1)) {
jbe@154 1253 lua_pop(L, 1);
jbe@154 1254 break;
jbe@154 1255 }
jbe@175 1256 // store value below Lua string buffer on stack (to allow operation on string buffer):
jbe@164 1257 lua_replace(L, json_export_internal_tmp_idx);
jbe@175 1258 //
jbe@175 1259 // add comma to output buffer unless we process the first element:
jbe@164 1260 if (anyelement) luaL_addchar(&buf, ',');
jbe@175 1261 // remember that we processed an element:
jbe@164 1262 anyelement = 1;
jbe@175 1263 // handle indentation for pretty results:
jbe@164 1264 if (pretty) {
jbe@164 1265 luaL_addchar(&buf, '\n');
jbe@164 1266 for (i=0; i<level; i++) {
jbe@164 1267 lua_pushvalue(L, json_export_internal_indentstring_idx);
jbe@164 1268 luaL_addvalue(&buf);
jbe@164 1269 }
jbe@164 1270 }
jbe@175 1271 // recursive call to encode previously stored value:
jbe@164 1272 lua_pushcfunction(L, json_export_internal);
jbe@164 1273 lua_pushvalue(L, json_export_internal_indentstring_idx);
jbe@164 1274 lua_pushinteger(L, level);
jbe@164 1275 lua_pushvalue(L, json_export_internal_tmp_idx);
jbe@164 1276 lua_call(L, 3, 1);
jbe@175 1277 // add encoded value to output buffer:
jbe@154 1278 luaL_addvalue(&buf);
jbe@154 1279 }
jbe@175 1280 // decrement level variable for all following statements:
jbe@175 1281 level--;
jbe@175 1282 // handle indentation for pretty results:
jbe@164 1283 if (pretty && anyelement) {
jbe@164 1284 luaL_addchar(&buf, '\n');
jbe@175 1285 for (i=0; i<level; i++) {
jbe@164 1286 lua_pushvalue(L, json_export_internal_indentstring_idx);
jbe@164 1287 luaL_addvalue(&buf);
jbe@164 1288 }
jbe@164 1289 }
jbe@175 1290 // add closing bracket to output buffer:
jbe@154 1291 luaL_addchar(&buf, ']');
jbe@175 1292 // for pretty results, add final newline character if outermost container is processed:
jbe@175 1293 if (pretty && level == 0) luaL_addchar(&buf, '\n');
jbe@175 1294 // convert and return buffer:
jbe@154 1295 luaL_pushresult(&buf);
jbe@154 1296 return 1;
jbe@154 1297 }
jbe@175 1298 // throw error if table type is unknown:
jbe@154 1299 json_export_tabletype_error:
jbe@154 1300 return luaL_error(L, "JSON export not possible for ambiguous table (cannot decide whether it is an object or array)");
jbe@154 1301 }
jbe@175 1302 // all other datatypes are considered an error:
jbe@166 1303 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 1304 }
jbe@154 1305
jbe@175 1306 // encodes a JSON document (passed as argument):
jbe@164 1307 static int json_export(lua_State *L) {
jbe@175 1308 // stack shall contain one function argument:
jbe@164 1309 lua_settop(L, 1);
jbe@175 1310 // call json_export_internal function with proper arguments:
jbe@164 1311 lua_pushcfunction(L, json_export_internal);
jbe@164 1312 lua_pushnil(L);
jbe@164 1313 lua_pushinteger(L, 0);
jbe@164 1314 lua_pushvalue(L, 1);
jbe@164 1315 lua_call(L, 3, 1);
jbe@175 1316 // return result:
jbe@164 1317 return 1;
jbe@164 1318 }
jbe@164 1319
jbe@175 1320 // encodes a JSON document (passed as first argument)
jbe@175 1321 // with indentation (indentation string may be passed as second argument):
jbe@164 1322 static int json_pretty(lua_State *L) {
jbe@175 1323 // stack shall contain two function arguments:
jbe@164 1324 lua_settop(L, 2);
jbe@175 1325 // call json_export_internal function with proper arguments:
jbe@164 1326 lua_pushcfunction(L, json_export_internal);
jbe@164 1327 if (lua_isnil(L, 2)) lua_pushliteral(L, " ");
jbe@164 1328 else lua_pushvalue(L, 2);
jbe@164 1329 lua_pushinteger(L, 0);
jbe@164 1330 lua_pushvalue(L, 1);
jbe@164 1331 lua_call(L, 3, 1);
jbe@175 1332 // return result:
jbe@164 1333 return 1;
jbe@164 1334 }
jbe@164 1335
jbe@149 1336 // functions in library module:
jbe@121 1337 static const struct luaL_Reg json_module_functions[] = {
jbe@133 1338 {"object", json_object},
jbe@173 1339 {"array", json_array},
jbe@121 1340 {"import", json_import},
jbe@154 1341 {"export", json_export},
jbe@164 1342 {"pretty", json_pretty},
jbe@173 1343 {"get", json_get},
jbe@173 1344 {"type", json_type},
jbe@173 1345 {"set", json_set},
jbe@121 1346 {NULL, NULL}
jbe@121 1347 };
jbe@121 1348
jbe@149 1349 // metamethods for JSON objects, JSON arrays, and unknown JSON collections (object or array):
jbe@126 1350 static const struct luaL_Reg json_metatable_functions[] = {
jbe@130 1351 {"__len", json_len},
jbe@130 1352 {"__index", json_index},
jbe@130 1353 {"__newindex", json_newindex},
jbe@135 1354 {"__pairs", json_pairs},
jbe@134 1355 {"__ipairs", json_ipairs},
jbe@160 1356 {"__tostring", json_export},
jbe@126 1357 {NULL, NULL}
jbe@126 1358 };
jbe@126 1359
jbe@157 1360 // metamethods for JSON null marker:
jbe@157 1361 static const struct luaL_Reg json_nullmark_metamethods[] = {
jbe@157 1362 {"__tostring", json_nullmark_tostring},
jbe@157 1363 {NULL, NULL}
jbe@157 1364 };
jbe@157 1365
jbe@149 1366 // initializes json library:
jbe@121 1367 int luaopen_json(lua_State *L) {
jbe@149 1368 // empty stack:
jbe@126 1369 lua_settop(L, 0);
jbe@149 1370 // push library module onto stack position 1:
jbe@149 1371 lua_newtable(L);
jbe@149 1372 // register library functions:
jbe@149 1373 luaL_setfuncs(L, json_module_functions, 0);
jbe@149 1374 // create and store objectmt:
jbe@138 1375 lua_newtable(L);
jbe@138 1376 luaL_setfuncs(L, json_metatable_functions, 0);
jbe@144 1377 json_regstore(L, objectmt);
jbe@149 1378 // create and store arraymt:
jbe@138 1379 lua_newtable(L);
jbe@138 1380 luaL_setfuncs(L, json_metatable_functions, 0);
jbe@144 1381 json_regstore(L, arraymt);
jbe@149 1382 // create and store ephemeron table to store shadow tables for each JSON object/array
jbe@149 1383 // to allow NULL values returned as nil
jbe@149 1384 lua_newtable(L);
jbe@138 1385 lua_newtable(L); // metatable for ephemeron table
jbe@121 1386 lua_pushliteral(L, "__mode");
jbe@121 1387 lua_pushliteral(L, "k");
jbe@138 1388 lua_rawset(L, -3);
jbe@138 1389 lua_setmetatable(L, -2);
jbe@144 1390 json_regstore(L, shadowtbl);
jbe@157 1391 // set metatable of null marker and make it available through library module:
jbe@157 1392 json_pushnullmark(L);
jbe@157 1393 lua_newtable(L);
jbe@157 1394 luaL_setfuncs(L, json_nullmark_metamethods, 0);
jbe@157 1395 lua_setmetatable(L, -2);
jbe@157 1396 lua_setfield(L, 1, "null");
jbe@157 1397 // return library module (that's expected on top of stack):
jbe@121 1398 return 1;
jbe@121 1399 }

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