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annotate libraries/json/json.c @ 182:b460ae08dd78

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json.import does support even more nested levels
author jbe
date Sat Aug 02 02:53:32 2014 +0200 (2014-08-02)
parents c2e76617c26c
children f7c1869b5b32
rev   line source
jbe@121 1 #include <lua.h>
jbe@121 2 #include <lauxlib.h>
jbe@122 3 #include <stdlib.h>
jbe@121 4 #include <string.h>
jbe@154 5 #include <math.h>
jbe@121 6
jbe@144 7 // maximum number of nested JSON values (objects and arrays):
jbe@182 8 // NOTE: json_import can store 2^32 / 3 levels on stack swap (using
jbe@182 9 // also negative indicies after integer wraparound), so
jbe@182 10 // 1024^3 = 1073741824 is a safe value.
jbe@182 11 #define JSON_MAXDEPTH (1024*1024*1024)
jbe@179 12 // NOTE: As long as the function json_export_internal is implemented
jbe@179 13 // recursively, JSON_MAXDEPTH needs to be low (e.g. 50) to avoid C stack
jbe@179 14 // overflows.
jbe@179 15 #if JSON_MAXDEPTH > 50
jbe@180 16 #undef JSON_MAXDEPTH
jbe@179 17 #define JSON_MAXDEPTH 50
jbe@179 18 #endif
jbe@142 19
jbe@155 20 // generate dummy memory addresses that represents null values:
jbe@155 21 char json_nullmark;
jbe@155 22 #define json_isnullmark(L, i) (lua_touserdata((L), (i)) == &json_nullmark)
jbe@155 23 #define json_pushnullmark(L) lua_pushlightuserdata((L), &json_nullmark)
jbe@155 24
jbe@144 25 // macros for usage of Lua registry:
jbe@144 26 #define JSON_REGENT char
jbe@145 27 #define JSON_REGPOINTER void *
jbe@145 28 #define json_regpointer(x) (&json_registry.x)
jbe@151 29 #define json_regfetchpointer(L, x) lua_rawgetp((L), LUA_REGISTRYINDEX, (x))
jbe@151 30 #define json_regfetch(L, x) json_regfetchpointer(L, json_regpointer(x))
jbe@151 31 #define json_regstore(L, x) lua_rawsetp(L, LUA_REGISTRYINDEX, json_regpointer(x))
jbe@145 32
jbe@144 33 // generate dummy memory addresses that represent Lua objects
jbe@145 34 // via lightuserdata keys and LUA_REGISTRYINDEX:
jbe@144 35 static struct {
jbe@145 36 JSON_REGENT shadowtbl; // ephemeron table that maps tables to their corresponding shadow table
jbe@145 37 JSON_REGENT objectmt; // metatable for JSON objects
jbe@145 38 JSON_REGENT arraymt; // metatable for JSON arrays
jbe@144 39 } json_registry;
jbe@138 40
jbe@157 41 // returns the string "<JSON null marker>":
jbe@157 42 static int json_nullmark_tostring(lua_State *L) {
jbe@157 43 lua_pushliteral(L, "<JSON null marker>");
jbe@157 44 return 1;
jbe@157 45 }
jbe@157 46
jbe@169 47 #define json_convert_source_idx 1
jbe@169 48 #define json_convert_iterator_idx 2
jbe@169 49 #define json_convert_output_idx 3
jbe@169 50 #define json_convert_shadow_idx 4
jbe@172 51 #define json_convert_iterfun_idx 5
jbe@172 52 #define json_convert_itertbl_idx 6
jbe@169 53
jbe@175 54 // converts a Lua table (or any other iterable value) to a JSON object or JSON array:
jbe@169 55 // (does never modify the argument, returns an empty object or array if argument is nil)
jbe@169 56 static int json_convert(lua_State *L, int array) {
jbe@171 57 int arrayidx = 0;
jbe@171 58 // determine is argument is given:
jbe@169 59 if (lua_isnoneornil(L, json_convert_source_idx)) {
jbe@171 60 // if no argument is given (or if argument is nil),
jbe@171 61 // create table with shadow table, and leave first table on top of stack:
jbe@144 62 json_regfetch(L, shadowtbl);
jbe@169 63 lua_newtable(L);
jbe@169 64 lua_pushvalue(L, -1);
jbe@169 65 lua_newtable(L);
jbe@169 66 lua_rawset(L, -4);
jbe@169 67 } else {
jbe@171 68 // if an argument was given,
jbe@171 69 // push its iterator function on stack position 2 if existent,
jbe@169 70 // else push null for normal tables:
jbe@171 71 lua_settop(L, 1);
jbe@169 72 if (lua_getmetatable(L, json_convert_source_idx)) {
jbe@169 73 lua_getfield(L, -1, array ? "__ipairs" : "__pairs");
jbe@169 74 if (lua_isnil(L, -1)) luaL_checktype(L, 1, LUA_TTABLE);
jbe@169 75 else if (lua_type(L, -1) != LUA_TFUNCTION)
jbe@169 76 return luaL_error(L, "%s metamethod is not a function", array ? "__ipairs" : "__pairs");
jbe@169 77 lua_replace(L, -2);
jbe@169 78 } else {
jbe@169 79 lua_pushnil(L);
jbe@143 80 }
jbe@171 81 // create result table on stack position 3:
jbe@169 82 lua_newtable(L);
jbe@169 83 // create shadow table on stack position 4:
jbe@169 84 json_regfetch(L, shadowtbl);
jbe@169 85 lua_newtable(L);
jbe@169 86 lua_pushvalue(L, json_convert_output_idx);
jbe@169 87 lua_pushvalue(L, -2);
jbe@169 88 lua_rawset(L, -4);
jbe@169 89 lua_replace(L, -2);
jbe@171 90 // check if iterator function exists:
jbe@169 91 if (lua_isnil(L, json_convert_iterator_idx)) {
jbe@171 92 // if there is no iterator function,
jbe@171 93 // distinguish between objects and arrays:
jbe@171 94 if (array == 0) {
jbe@171 95 // for an object, copy all string key value pairs to shadow table:
jbe@171 96 for (lua_pushnil(L); lua_next(L, json_convert_source_idx); lua_pop(L, 1)) {
jbe@171 97 if (lua_type(L, -2) == LUA_TSTRING) {
jbe@171 98 lua_pushvalue(L, -2);
jbe@171 99 lua_pushvalue(L, -2);
jbe@171 100 lua_rawset(L, json_convert_shadow_idx);
jbe@171 101 }
jbe@171 102 }
jbe@171 103 } else {
jbe@171 104 // for an array, copy consecutive integer value pairs to shadow table:
jbe@171 105 while (1) {
jbe@175 106 // throw error if array would exceed INT_MAX elements:
jbe@171 107 // TODO: Lua 5.3 may support more elements
jbe@171 108 if (arrayidx == INT_MAX) {
jbe@171 109 lua_pushnumber(L, (size_t)INT_MAX+1);
jbe@171 110 lua_rawget(L, json_convert_source_idx);
jbe@171 111 if (lua_isnil(L, -1)) break;
jbe@171 112 return luaL_error(L, "Array exceeded length of %d elements", INT_MAX);
jbe@171 113 }
jbe@175 114 // get next array entry:
jbe@171 115 arrayidx++;
jbe@171 116 lua_rawgeti(L, json_convert_source_idx, arrayidx);
jbe@175 117 // break if value is nil:
jbe@171 118 if (lua_isnil(L, -1)) break;
jbe@175 119 // store value in shadow table:
jbe@171 120 lua_rawseti(L, json_convert_shadow_idx, arrayidx);
jbe@171 121 }
jbe@169 122 }
jbe@169 123 } else {
jbe@172 124 // if there is an iterator function,
jbe@172 125 // call iterator function with source value (first argument)
jbe@172 126 // and store 3 result values on stack positions 5 through 7:
jbe@172 127 lua_pushvalue(L, json_convert_iterator_idx);
jbe@172 128 lua_pushvalue(L, 1);
jbe@172 129 lua_call(L, 1, 3);
jbe@175 130 // iterate through key value pairs and store some of them in shadow table
jbe@174 131 // while replacing nil values with null-marker:
jbe@172 132 while (1) {
jbe@175 133 // call iterfun function:
jbe@172 134 lua_pushvalue(L, json_convert_iterfun_idx);
jbe@172 135 lua_pushvalue(L, json_convert_itertbl_idx);
jbe@172 136 lua_pushvalue(L, -3);
jbe@172 137 lua_remove(L, -4);
jbe@172 138 lua_call(L, 2, 2);
jbe@175 139 // break iteration loop if key is nil:
jbe@172 140 if (lua_isnil(L, -2)) break;
jbe@175 141 // store key value pair only if key type is correct:
jbe@172 142 if (lua_type(L, -2) == (array ? LUA_TNUMBER : LUA_TSTRING)) {
jbe@175 143 // if key type is correct,
jbe@175 144 // push key onto stack:
jbe@172 145 lua_pushvalue(L, -2);
jbe@175 146 // if value is nil, push null-marker onto stack (as value):
jbe@174 147 if (lua_isnil(L, -2)) json_pushnullmark(L);
jbe@175 148 // else push value onto stack:
jbe@174 149 else lua_pushvalue(L, -2);
jbe@175 150 // set key value pair in shadow table:
jbe@172 151 lua_rawset(L, json_convert_shadow_idx);
jbe@172 152 }
jbe@175 153 // pop value from stack, but leave key on stack:
jbe@172 154 lua_pop(L, 1);
jbe@172 155 }
jbe@143 156 }
jbe@171 157 // let result table be on top of stack:
jbe@169 158 lua_settop(L, json_convert_output_idx);
jbe@136 159 }
jbe@171 160 // set metatable (for result table on top of stack):
jbe@171 161 if (array == 0) json_regfetch(L, objectmt);
jbe@171 162 else json_regfetch(L, arraymt);
jbe@169 163 lua_setmetatable(L, -2);
jbe@171 164 // return table on top of stack:
jbe@136 165 return 1;
jbe@136 166 }
jbe@136 167
jbe@175 168 // converts a Lua table (or any other iterable value) to a JSON object:
jbe@175 169 // (does never modify the argument, returns an empty object or array if argument is nil)
jbe@136 170 static int json_object(lua_State *L) {
jbe@169 171 return json_convert(L, 0);
jbe@136 172 }
jbe@136 173
jbe@175 174 // converts a Lua table (or any other iterable value) to a JSON array:
jbe@175 175 // (does never modify the argument, returns an empty object or array if argument is nil)
jbe@136 176 static int json_array(lua_State *L) {
jbe@169 177 return json_convert(L, 1);
jbe@136 178 }
jbe@136 179
jbe@145 180 // internal states of JSON parser:
jbe@124 181 #define JSON_STATE_VALUE 0
jbe@124 182 #define JSON_STATE_OBJECT_KEY 1
jbe@124 183 #define JSON_STATE_OBJECT_KEY_TERMINATOR 2
jbe@124 184 #define JSON_STATE_OBJECT_VALUE 3
jbe@124 185 #define JSON_STATE_OBJECT_SEPARATOR 4
jbe@124 186 #define JSON_STATE_ARRAY_VALUE 5
jbe@124 187 #define JSON_STATE_ARRAY_SEPARATOR 6
jbe@124 188 #define JSON_STATE_END 7
jbe@121 189
jbe@145 190 // special Lua stack indicies for json_import function:
jbe@138 191 #define json_import_objectmt_idx 2
jbe@138 192 #define json_import_arraymt_idx 3
jbe@138 193 #define json_import_shadowtbl_idx 4
jbe@181 194 #define json_import_stackswap_idx 5
jbe@138 195
jbe@168 196 // macros for hex decoding:
jbe@168 197 #define json_utf16_surrogate(x) ((x) >= 0xD800 && (x) <= 0xDFFF)
jbe@168 198 #define json_utf16_lead(x) ((x) >= 0xD800 && (x) <= 0xDBFF)
jbe@168 199 #define json_utf16_tail(x) ((x) >= 0xDC00 && (x) <= 0xDFFF)
jbe@167 200 #define json_import_readhex(x) \
jbe@167 201 do { \
jbe@167 202 x = 0; \
jbe@167 203 for (i=0; i<4; i++) { \
jbe@167 204 x <<= 4; \
jbe@167 205 c = str[pos++]; \
jbe@167 206 if (c >= '0' && c <= '9') x += c - '0'; \
jbe@167 207 else if (c >= 'A' && c <= 'F') x += c - 'A' + 10; \
jbe@167 208 else if (c >= 'a' && c <= 'f') x += c - 'a' + 10; \
jbe@167 209 else if (c == 0) goto json_import_unexpected_eof; \
jbe@167 210 else goto json_import_unexpected_escape; \
jbe@167 211 } \
jbe@167 212 } while (0)
jbe@167 213
jbe@136 214 // decodes a JSON document:
jbe@121 215 static int json_import(lua_State *L) {
jbe@181 216 int stackswapidx = 0; // elements in stack swap table
jbe@181 217 int i; // loop variable
jbe@181 218 const char *str; // string to parse
jbe@181 219 size_t total; // total length of string to parse
jbe@181 220 size_t pos = 0; // current position in string to parse
jbe@181 221 size_t level = 0; // nested levels of objects/arrays currently being processed
jbe@145 222 int mode = JSON_STATE_VALUE; // state of parser (i.e. "what's expected next?")
jbe@181 223 unsigned char c; // variable to store a single character to be processed (unsigned!)
jbe@181 224 luaL_Buffer luabuf; // Lua buffer to decode JSON string values
jbe@181 225 char *cbuf; // C buffer to decode JSON string values
jbe@181 226 size_t outlen; // maximum length or write position of C buffer
jbe@181 227 long codepoint; // decoded UTF-16 character or higher codepoint
jbe@181 228 long utf16tail; // second decoded UTF-16 character (surrogate tail)
jbe@181 229 size_t arraylen; // variable to temporarily store the array length
jbe@166 230 // require string as argument and convert to C string with length information:
jbe@166 231 str = luaL_checklstring(L, 1, &total);
jbe@166 232 // if string contains a NULL byte, this is a syntax error
jbe@166 233 if (strlen(str) != total) goto json_import_syntax_error;
jbe@147 234 // stack shall contain one function argument:
jbe@138 235 lua_settop(L, 1);
jbe@147 236 // push objectmt onto stack position 2:
jbe@144 237 json_regfetch(L, objectmt);
jbe@147 238 // push arraymt onto stack position 3:
jbe@144 239 json_regfetch(L, arraymt);
jbe@147 240 // push shadowtbl onto stack position 4:
jbe@144 241 json_regfetch(L, shadowtbl);
jbe@181 242 // push table for stack swapping onto stack position 5:
jbe@181 243 // (needed to avoid Lua stack overflows)
jbe@181 244 lua_newtable(L);
jbe@136 245 // main loop of parser:
jbe@136 246 json_import_loop:
jbe@136 247 // skip whitespace and store next character in variable 'c':
jbe@146 248 while (c = str[pos],
jbe@146 249 c == ' ' ||
jbe@146 250 c == '\f' ||
jbe@146 251 c == '\n' ||
jbe@146 252 c == '\r' ||
jbe@146 253 c == '\t' ||
jbe@146 254 c == '\v'
jbe@146 255 ) pos++;
jbe@170 256 // NOTE: variable c needs to be unsigned in the following code
jbe@136 257 // switch statement to handle certain (single) characters:
jbe@121 258 switch (c) {
jbe@136 259 // handle end of JSON document:
jbe@121 260 case 0:
jbe@136 261 // if end of JSON document was expected, then return top element of stack as result:
jbe@124 262 if (mode == JSON_STATE_END) return 1;
jbe@136 263 // otherwise, the JSON document was malformed:
jbe@167 264 if (level == 0) {
jbe@167 265 lua_pushnil(L);
jbe@167 266 lua_pushliteral(L, "Empty string");
jbe@167 267 } else {
jbe@167 268 json_import_unexpected_eof:
jbe@167 269 lua_pushnil(L);
jbe@167 270 lua_pushliteral(L, "Unexpected end of JSON document");
jbe@167 271 }
jbe@121 272 return 2;
jbe@181 273 // new JSON object or JSON array:
jbe@121 274 case '{':
jbe@181 275 case '[':
jbe@181 276 // if an encountered JSON object is not expected here, then return an error:
jbe@146 277 if (
jbe@181 278 c == '{' &&
jbe@181 279 mode != JSON_STATE_VALUE &&
jbe@181 280 mode != JSON_STATE_OBJECT_VALUE &&
jbe@181 281 mode != JSON_STATE_ARRAY_VALUE
jbe@181 282 ) goto json_import_syntax_error;
jbe@181 283 // if an encountered JSON array is not expected here, then return an error:
jbe@181 284 if (
jbe@181 285 c == '[' &&
jbe@146 286 mode != JSON_STATE_VALUE &&
jbe@146 287 mode != JSON_STATE_OBJECT_VALUE &&
jbe@146 288 mode != JSON_STATE_ARRAY_VALUE
jbe@146 289 ) goto json_import_syntax_error;
jbe@181 290 // consume input character:
jbe@181 291 pos++;
jbe@181 292 // limit nested levels:
jbe@181 293 if (level >= JSON_MAXDEPTH) {
jbe@181 294 lua_pushnil(L);
jbe@181 295 lua_pushfstring(L, "More than %d nested JSON levels", JSON_MAXDEPTH);
jbe@181 296 return 2;
jbe@181 297 }
jbe@181 298 // swap Lua stack entries for previous level to swap table:
jbe@181 299 // (avoids depth limitations due to Lua stack size)
jbe@181 300 if (level) {
jbe@181 301 lua_rawseti(L, json_import_stackswap_idx, ++stackswapidx);
jbe@181 302 lua_rawseti(L, json_import_stackswap_idx, ++stackswapidx);
jbe@181 303 lua_rawseti(L, json_import_stackswap_idx, ++stackswapidx);
jbe@181 304 }
jbe@181 305 // increment level:
jbe@181 306 level++;
jbe@181 307 // create JSON object or JSON array on stack:
jbe@136 308 lua_newtable(L);
jbe@181 309 // set metatable of JSON object or JSON array:
jbe@181 310 lua_pushvalue(L, c == '{' ? json_import_objectmt_idx : json_import_arraymt_idx);
jbe@125 311 lua_setmetatable(L, -2);
jbe@136 312 // create internal shadow table on stack:
jbe@136 313 lua_newtable(L);
jbe@146 314 // register internal shadow table:
jbe@123 315 lua_pushvalue(L, -2);
jbe@123 316 lua_pushvalue(L, -2);
jbe@138 317 lua_rawset(L, json_import_shadowtbl_idx);
jbe@181 318 // distinguish between JSON objects and JSON arrays:
jbe@181 319 if (c == '{') {
jbe@181 320 // if JSON object,
jbe@181 321 // expect object key (or end of object) to follow:
jbe@181 322 mode = JSON_STATE_OBJECT_KEY;
jbe@181 323 } else {
jbe@181 324 // if JSON array,
jbe@181 325 // expect array value (or end of array) to follow:
jbe@181 326 mode = JSON_STATE_ARRAY_VALUE;
jbe@181 327 // add nil as key (needed to keep stack balance) and as magic to detect arrays:
jbe@181 328 if (c == '[') lua_pushnil(L);
jbe@142 329 }
jbe@121 330 goto json_import_loop;
jbe@136 331 // end of JSON object:
jbe@121 332 case '}':
jbe@136 333 // if end of JSON object is not expected here, then return an error:
jbe@146 334 if (
jbe@146 335 mode != JSON_STATE_OBJECT_KEY &&
jbe@146 336 mode != JSON_STATE_OBJECT_SEPARATOR
jbe@146 337 ) goto json_import_syntax_error;
jbe@136 338 // jump to common code for end of JSON object and JSON array:
jbe@121 339 goto json_import_close;
jbe@136 340 // end of JSON array:
jbe@121 341 case ']':
jbe@136 342 // if end of JSON array is not expected here, then return an error:
jbe@146 343 if (
jbe@146 344 mode != JSON_STATE_ARRAY_VALUE &&
jbe@146 345 mode != JSON_STATE_ARRAY_SEPARATOR
jbe@146 346 ) goto json_import_syntax_error;
jbe@146 347 // pop nil key/magic (that was needed to keep stack balance):
jbe@140 348 lua_pop(L, 1);
jbe@136 349 // continue with common code for end of JSON object and JSON array:
jbe@136 350 // common code for end of JSON object or JSON array:
jbe@121 351 json_import_close:
jbe@136 352 // consume input character:
jbe@121 353 pos++;
jbe@136 354 // pop shadow table:
jbe@136 355 lua_pop(L, 1);
jbe@136 356 // check if nested:
jbe@121 357 if (--level) {
jbe@146 358 // if nested,
jbe@181 359 // restore previous stack elements from stack swap:
jbe@181 360 lua_rawgeti(L, json_import_stackswap_idx, stackswapidx--);
jbe@181 361 lua_insert(L, -2);
jbe@181 362 lua_rawgeti(L, json_import_stackswap_idx, stackswapidx--);
jbe@181 363 lua_insert(L, -2);
jbe@181 364 lua_rawgeti(L, json_import_stackswap_idx, stackswapidx--);
jbe@181 365 lua_insert(L, -2);
jbe@146 366 // check if outer(!) structure is an array or object:
jbe@140 367 if (lua_isnil(L, -2)) {
jbe@136 368 // select array value processing:
jbe@124 369 mode = JSON_STATE_ARRAY_VALUE;
jbe@121 370 } else {
jbe@136 371 // select object value processing:
jbe@124 372 mode = JSON_STATE_OBJECT_VALUE;
jbe@121 373 }
jbe@136 374 // store value in outer structure:
jbe@121 375 goto json_import_process_value;
jbe@121 376 }
jbe@136 377 // if not nested, then expect end of JSON document and continue with loop:
jbe@136 378 mode = JSON_STATE_END;
jbe@121 379 goto json_import_loop;
jbe@136 380 // key terminator:
jbe@121 381 case ':':
jbe@136 382 // if key terminator is not expected here, then return an error:
jbe@124 383 if (mode != JSON_STATE_OBJECT_KEY_TERMINATOR)
jbe@121 384 goto json_import_syntax_error;
jbe@136 385 // consume input character:
jbe@121 386 pos++;
jbe@146 387 // expect object value to follow:
jbe@124 388 mode = JSON_STATE_OBJECT_VALUE;
jbe@146 389 // continue with loop:
jbe@121 390 goto json_import_loop;
jbe@136 391 // value terminator (NOTE: trailing comma at end of value or key-value list is tolerated by this parser)
jbe@121 392 case ',':
jbe@146 393 // branch according to parser state:
jbe@124 394 if (mode == JSON_STATE_OBJECT_SEPARATOR) {
jbe@146 395 // expect an object key to follow:
jbe@124 396 mode = JSON_STATE_OBJECT_KEY;
jbe@124 397 } else if (mode == JSON_STATE_ARRAY_SEPARATOR) {
jbe@146 398 // expect an array value to follow:
jbe@124 399 mode = JSON_STATE_ARRAY_VALUE;
jbe@121 400 } else {
jbe@136 401 // if value terminator is not expected here, then return an error:
jbe@136 402 goto json_import_syntax_error;
jbe@121 403 }
jbe@136 404 // consume input character:
jbe@121 405 pos++;
jbe@136 406 // continue with loop:
jbe@121 407 goto json_import_loop;
jbe@136 408 // string literal:
jbe@121 409 case '"':
jbe@146 410 // consume quote character:
jbe@146 411 pos++;
jbe@162 412 // find last character in input string:
jbe@162 413 outlen = pos;
jbe@162 414 while ((c = str[outlen]) != '"') {
jbe@161 415 // consume one character:
jbe@162 416 outlen++;
jbe@161 417 // handle unexpected end of JSON document:
jbe@161 418 if (c == 0) goto json_import_unexpected_eof;
jbe@161 419 // consume one extra character when encountering an escaped quote:
jbe@162 420 else if (c == '\\' && str[outlen] == '"') outlen++;
jbe@161 421 }
jbe@162 422 // determine buffer length:
jbe@162 423 outlen -= pos;
jbe@161 424 // check if string is non empty:
jbe@162 425 if (outlen) {
jbe@161 426 // prepare buffer to decode string (with maximum possible length) and set write position to zero:
jbe@162 427 cbuf = luaL_buffinitsize(L, &luabuf, outlen);
jbe@162 428 outlen = 0;
jbe@161 429 // loop through the characters until encountering end quote:
jbe@161 430 while ((c = str[pos++]) != '"') {
jbe@162 431 // NOTE: unexpected end cannot happen anymore
jbe@162 432 if (c < 32 || c == 127) {
jbe@161 433 // do not allow ASCII control characters:
jbe@161 434 // NOTE: illegal UTF-8 sequences and extended control characters are not sanitized
jbe@161 435 // by this parser to allow different encodings than Unicode
jbe@161 436 lua_pushnil(L);
jbe@161 437 lua_pushliteral(L, "Unexpected control character in JSON string");
jbe@161 438 return 2;
jbe@161 439 } else if (c == '\\') {
jbe@161 440 // read next char after backslash escape:
jbe@161 441 c = str[pos++];
jbe@161 442 switch (c) {
jbe@161 443 // unexpected end-of-string:
jbe@161 444 case 0:
jbe@161 445 goto json_import_unexpected_eof;
jbe@161 446 // unescaping of quotation mark, slash, and backslash:
jbe@161 447 case '"':
jbe@161 448 case '/':
jbe@161 449 case '\\':
jbe@162 450 cbuf[outlen++] = c;
jbe@161 451 break;
jbe@161 452 // unescaping of backspace:
jbe@162 453 case 'b': cbuf[outlen++] = '\b'; break;
jbe@161 454 // unescaping of form-feed:
jbe@162 455 case 'f': cbuf[outlen++] = '\f'; break;
jbe@161 456 // unescaping of new-line:
jbe@162 457 case 'n': cbuf[outlen++] = '\n'; break;
jbe@161 458 // unescaping of carriage-return:
jbe@162 459 case 'r': cbuf[outlen++] = '\r'; break;
jbe@161 460 // unescaping of tabulator:
jbe@162 461 case 't': cbuf[outlen++] = '\t'; break;
jbe@161 462 // unescaping of UTF-16 characters
jbe@161 463 case 'u':
jbe@167 464 // decode 4 hex nibbles:
jbe@167 465 json_import_readhex(codepoint);
jbe@167 466 // handle surrogate character:
jbe@167 467 if (json_utf16_surrogate(codepoint)) {
jbe@167 468 // check if first surrogate is in valid range:
jbe@167 469 if (json_utf16_lead(codepoint)) {
jbe@167 470 // require second surrogate:
jbe@167 471 if ((c = str[pos++]) != '\\' || (c = str[pos++]) != 'u') {
jbe@167 472 if (c == 0) goto json_import_unexpected_eof;
jbe@167 473 else goto json_import_wrong_surrogate;
jbe@167 474 }
jbe@167 475 // read 4 hex nibbles of second surrogate character:
jbe@167 476 json_import_readhex(utf16tail);
jbe@167 477 // check if second surrogate is in valid range:
jbe@167 478 if (!json_utf16_tail(utf16tail)) goto json_import_wrong_surrogate;
jbe@167 479 // calculate codepoint:
jbe@167 480 codepoint = 0x10000 + (utf16tail - 0xDC00) + (codepoint - 0xD800) * 0x400;
jbe@167 481 } else {
jbe@167 482 // throw error for wrong surrogates:
jbe@167 483 json_import_wrong_surrogate:
jbe@167 484 lua_pushnil(L);
jbe@167 485 lua_pushliteral(L, "Illegal UTF-16 surrogate in JSON string escape sequence");
jbe@167 486 return 2;
jbe@167 487 }
jbe@167 488 }
jbe@167 489 // encode as UTF-8:
jbe@167 490 if (codepoint < 0x80) {
jbe@167 491 cbuf[outlen++] = (char)codepoint;
jbe@167 492 } else if (codepoint < 0x800) {
jbe@167 493 cbuf[outlen++] = (char)(0xc0 | (codepoint >> 6));
jbe@167 494 cbuf[outlen++] = (char)(0x80 | (codepoint & 0x3f));
jbe@167 495 } else if (codepoint < 0x10000) {
jbe@167 496 cbuf[outlen++] = (char)(0xe0 | (codepoint >> 12));
jbe@167 497 cbuf[outlen++] = (char)(0x80 | ((codepoint >> 6) & 0x3f));
jbe@167 498 cbuf[outlen++] = (char)(0x80 | (codepoint & 0x3f));
jbe@167 499 } else {
jbe@167 500 cbuf[outlen++] = (char)(0xf0 | (codepoint >> 18));
jbe@167 501 cbuf[outlen++] = (char)(0x80 | ((codepoint >> 12) & 0x3f));
jbe@167 502 cbuf[outlen++] = (char)(0x80 | ((codepoint >> 6) & 0x3f));
jbe@167 503 cbuf[outlen++] = (char)(0x80 | (codepoint & 0x3f));
jbe@167 504 }
jbe@167 505 break;
jbe@161 506 // unexpected escape sequence:
jbe@161 507 default:
jbe@167 508 json_import_unexpected_escape:
jbe@161 509 lua_pushnil(L);
jbe@161 510 lua_pushliteral(L, "Unexpected string escape sequence in JSON document");
jbe@161 511 return 2;
jbe@161 512 }
jbe@161 513 } else {
jbe@161 514 // normal character:
jbe@162 515 cbuf[outlen++] = c;
jbe@121 516 }
jbe@121 517 }
jbe@161 518 // process buffer to Lua string:
jbe@162 519 luaL_pushresultsize(&luabuf, outlen);
jbe@161 520 } else {
jbe@161 521 // if JSON string is empty,
jbe@161 522 // push empty Lua string:
jbe@161 523 lua_pushliteral(L, "");
jbe@167 524 // consume closing quote:
jbe@167 525 pos++;
jbe@121 526 }
jbe@136 527 // continue with processing of decoded string:
jbe@121 528 goto json_import_process_value;
jbe@121 529 }
jbe@136 530 // process values whose type is is not deducible from a single character:
jbe@136 531 if ((c >= '0' && c <= '9') || c == '-' || c == '+') {
jbe@146 532 // for numbers,
jbe@146 533 // use strtod() call to parse a (double precision) floating point number:
jbe@167 534 double numval;
jbe@122 535 char *endptr;
jbe@122 536 numval = strtod(str+pos, &endptr);
jbe@146 537 // catch parsing errors:
jbe@122 538 if (endptr == str+pos) goto json_import_syntax_error;
jbe@146 539 // consume characters that were parsed:
jbe@122 540 pos += endptr - (str+pos);
jbe@146 541 // push parsed (double precision) floating point number on Lua stack:
jbe@122 542 lua_pushnumber(L, numval);
jbe@122 543 } else if (!strncmp(str+pos, "true", 4)) {
jbe@136 544 // consume 4 input characters for "true":
jbe@121 545 pos += 4;
jbe@147 546 // put Lua true value onto stack:
jbe@136 547 lua_pushboolean(L, 1);
jbe@121 548 } else if (!strncmp(str+pos, "false", 5)) {
jbe@136 549 // consume 5 input characters for "false":
jbe@121 550 pos += 5;
jbe@147 551 // put Lua false value onto stack:
jbe@136 552 lua_pushboolean(L, 0);
jbe@121 553 } else if (!strncmp(str+pos, "null", 4)) {
jbe@136 554 // consume 4 input characters for "null":
jbe@136 555 pos += 4;
jbe@153 556 // different behavor for top-level and sub-levels:
jbe@153 557 if (level) {
jbe@153 558 // if sub-level,
jbe@153 559 // push special null-marker onto stack:
jbe@155 560 json_pushnullmark(L);
jbe@153 561 } else {
jbe@153 562 // if top-level,
jbe@153 563 // push nil onto stack:
jbe@153 564 lua_pushnil(L);
jbe@153 565 }
jbe@121 566 } else {
jbe@136 567 // all other cases are a syntax error:
jbe@121 568 goto json_import_syntax_error;
jbe@121 569 }
jbe@136 570 // process a decoded value or key value pair (expected on top of Lua stack):
jbe@136 571 json_import_process_value:
jbe@121 572 switch (mode) {
jbe@136 573 // an object key has been read:
jbe@124 574 case JSON_STATE_OBJECT_KEY:
jbe@136 575 // if an object key is not a string, then this is a syntax error:
jbe@121 576 if (lua_type(L, -1) != LUA_TSTRING) goto json_import_syntax_error;
jbe@146 577 // expect key terminator to follow:
jbe@124 578 mode = JSON_STATE_OBJECT_KEY_TERMINATOR;
jbe@146 579 // continue with loop:
jbe@121 580 goto json_import_loop;
jbe@136 581 // a key value pair has been read:
jbe@124 582 case JSON_STATE_OBJECT_VALUE:
jbe@136 583 // store key value pair in outer shadow table:
jbe@130 584 lua_rawset(L, -3);
jbe@146 585 // expect value terminator (or end of object) to follow:
jbe@124 586 mode = JSON_STATE_OBJECT_SEPARATOR;
jbe@146 587 // continue with loop:
jbe@121 588 goto json_import_loop;
jbe@136 589 // an array value has been read:
jbe@124 590 case JSON_STATE_ARRAY_VALUE:
jbe@152 591 // get current array length:
jbe@152 592 arraylen = lua_rawlen(L, -3);
jbe@152 593 // throw error if array would exceed INT_MAX elements:
jbe@152 594 // TODO: Lua 5.3 may support more elements
jbe@152 595 if (arraylen >= INT_MAX) {
jbe@152 596 lua_pushnil(L);
jbe@152 597 lua_pushfstring(L, "Array exceeded length of %d elements", INT_MAX);
jbe@152 598 }
jbe@136 599 // store value in outer shadow table:
jbe@152 600 lua_rawseti(L, -3, arraylen + 1);
jbe@146 601 // expect value terminator (or end of object) to follow:
jbe@124 602 mode = JSON_STATE_ARRAY_SEPARATOR;
jbe@146 603 // continue with loop
jbe@121 604 goto json_import_loop;
jbe@136 605 // a single value has been read:
jbe@124 606 case JSON_STATE_VALUE:
jbe@136 607 // leave value on top of stack, expect end of JSON document, and continue with loop:
jbe@124 608 mode = JSON_STATE_END;
jbe@121 609 goto json_import_loop;
jbe@121 610 }
jbe@146 611 // syntax error handling (reachable by goto statement):
jbe@136 612 json_import_syntax_error:
jbe@121 613 lua_pushnil(L);
jbe@121 614 lua_pushliteral(L, "Syntax error in JSON document");
jbe@121 615 return 2;
jbe@121 616 }
jbe@121 617
jbe@146 618 // special Lua stack indicies for json_path function:
jbe@138 619 #define json_path_shadowtbl_idx 1
jbe@146 620
jbe@146 621 // stack offset of arguments to json_path function:
jbe@155 622 #define json_path_idxshift 1
jbe@138 623
jbe@146 624 // gets a value or its type from a JSON document (passed as first argument)
jbe@175 625 // using a path (passed as variable number of keys after the first argument):
jbe@137 626 static int json_path(lua_State *L, int type_mode) {
jbe@146 627 int stacktop; // stack index of top of stack (after shifting)
jbe@146 628 int idx = 2 + json_path_idxshift; // stack index of current argument to process
jbe@173 629 // require at least one argument:
jbe@173 630 luaL_checkany(L, 1);
jbe@148 631 // insert shadowtbl into stack at position 1 (shifting the arguments):
jbe@144 632 json_regfetch(L, shadowtbl);
jbe@138 633 lua_insert(L, 1);
jbe@146 634 // store stack index of top of stack:
jbe@138 635 stacktop = lua_gettop(L);
jbe@146 636 // use first argument as "current value" (stored on top of stack):
jbe@138 637 lua_pushvalue(L, 1 + json_path_idxshift);
jbe@146 638 // process each "path key" (2nd argument and following arguments):
jbe@138 639 while (idx <= stacktop) {
jbe@146 640 // if "current value" (on top of stack) is nil, then the path cannot be walked and nil is returned:
jbe@137 641 if (lua_isnil(L, -1)) return 1;
jbe@137 642 // try to get shadow table of "current value":
jbe@130 643 lua_pushvalue(L, -1);
jbe@138 644 lua_rawget(L, json_path_shadowtbl_idx);
jbe@126 645 if (lua_isnil(L, -1)) {
jbe@137 646 // if no shadow table is found,
jbe@130 647 if (lua_type(L, -1) == LUA_TTABLE) {
jbe@146 648 // and if "current value" is a table,
jbe@146 649 // drop nil from stack:
jbe@146 650 lua_pop(L, 1);
jbe@137 651 // get "next value" using the "path key":
jbe@130 652 lua_pushvalue(L, idx++);
jbe@130 653 lua_gettable(L, -2);
jbe@130 654 } else {
jbe@137 655 // if "current value" is not a table,
jbe@146 656 // then the path cannot be walked and nil (already on top of stack) is returned:
jbe@137 657 return 1;
jbe@130 658 }
jbe@130 659 } else {
jbe@137 660 // if a shadow table is found,
jbe@137 661 // set "current value" to its shadow table:
jbe@130 662 lua_replace(L, -2);
jbe@137 663 // get "next value" using the "path key":
jbe@130 664 lua_pushvalue(L, idx++);
jbe@130 665 lua_rawget(L, -2);
jbe@126 666 }
jbe@137 667 // the "next value" replaces the "current value":
jbe@130 668 lua_replace(L, -2);
jbe@126 669 }
jbe@137 670 if (!type_mode) {
jbe@137 671 // if a value (and not its type) was requested,
jbe@137 672 // check if value is the null-marker, and store nil on top of Lua stack in that case:
jbe@155 673 if (json_isnullmark(L, -1)) lua_pushnil(L);
jbe@137 674 } else {
jbe@137 675 // if the type was requested,
jbe@137 676 // check if value is the null-marker:
jbe@155 677 if (json_isnullmark(L, -1)) {
jbe@137 678 // if yes, store string "null" on top of Lua stack:
jbe@130 679 lua_pushliteral(L, "null");
jbe@137 680 } else {
jbe@137 681 // otherwise,
jbe@138 682 // check if metatable indicates "object" or "array":
jbe@138 683 if (lua_getmetatable(L, -1)) {
jbe@144 684 json_regfetch(L, objectmt);
jbe@138 685 if (lua_rawequal(L, -2, -1)) {
jbe@146 686 // if value has metatable for JSON objects,
jbe@138 687 // return string "object":
jbe@138 688 lua_pushliteral(L, "object");
jbe@138 689 return 1;
jbe@138 690 }
jbe@144 691 json_regfetch(L, arraymt);
jbe@138 692 if (lua_rawequal(L, -3, -1)) {
jbe@146 693 // if value has metatable for JSON arrays,
jbe@146 694 // return string "object":
jbe@138 695 lua_pushliteral(L, "array");
jbe@138 696 return 1;
jbe@138 697 }
jbe@146 698 // remove 3 metatables (one of the value, two for comparison) from stack:
jbe@138 699 lua_pop(L, 3);
jbe@138 700 }
jbe@138 701 // otherwise, get the Lua type:
jbe@138 702 lua_pushstring(L, lua_typename(L, lua_type(L, -1)));
jbe@126 703 }
jbe@126 704 }
jbe@137 705 // return the top most value on the Lua stack:
jbe@137 706 return 1;
jbe@130 707 }
jbe@130 708
jbe@147 709 // gets a value from a JSON document (passed as first argument)
jbe@175 710 // using a path (passed as variable number of keys after the first argument):
jbe@130 711 static int json_get(lua_State *L) {
jbe@137 712 return json_path(L, 0);
jbe@130 713 }
jbe@130 714
jbe@147 715 // gets a value's type from a JSON document (passed as first argument)
jbe@175 716 // using a path (passed as variable number of keys after first the argument):
jbe@130 717 static int json_type(lua_State *L) {
jbe@137 718 return json_path(L, 1);
jbe@130 719 }
jbe@130 720
jbe@173 721 // special Lua stack indicies for json_set function:
jbe@173 722 #define json_set_shadowtbl_idx 1
jbe@173 723 #define json_set_objectmt_idx 2
jbe@173 724 #define json_set_arraymt_idx 3
jbe@173 725
jbe@173 726 // stack offset of arguments to json_set function:
jbe@173 727 #define json_set_idxshift 3
jbe@173 728
jbe@173 729 // sets a value (passed as second argument) in a JSON document (passed as first argument)
jbe@175 730 // using a path (passed as variable number of keys starting at third argument):
jbe@173 731 static int json_set(lua_State *L) {
jbe@173 732 int stacktop; // stack index of top of stack (after shifting)
jbe@173 733 int idx = 3; // stack index of current argument to process
jbe@173 734 // require at least two arguments:
jbe@173 735 luaL_checkany(L, 1);
jbe@173 736 luaL_checkany(L, 2);
jbe@173 737 // insert shadowtbl into stack at position 1 (shifting the arguments):
jbe@173 738 json_regfetch(L, shadowtbl);
jbe@173 739 lua_insert(L, 1);
jbe@173 740 // insert objectmt into stack at position 2 (shifting the arguments):
jbe@173 741 json_regfetch(L, objectmt);
jbe@173 742 lua_insert(L, 2);
jbe@173 743 // insert arraymt into stack at position 3 (shifting the arguments):
jbe@173 744 json_regfetch(L, arraymt);
jbe@173 745 lua_insert(L, 3);
jbe@173 746 // store stack index of top of stack:
jbe@173 747 stacktop = lua_gettop(L);
jbe@173 748 // use nil as initial "parent value":
jbe@173 749 lua_pushnil(L);
jbe@173 750 // use first argument as "current value":
jbe@173 751 lua_pushvalue(L, 1 + json_set_idxshift);
jbe@173 752 // set all necessary values in path:
jbe@173 753 for (idx = 3 + json_set_idxshift; idx<=stacktop; idx++) {
jbe@173 754 // push metatable of "current value" onto stack:
jbe@173 755 if (!lua_getmetatable(L, -1)) lua_pushnil(L);
jbe@173 756 // distinguish according to type of path key:
jbe@173 757 switch (lua_type(L, idx)) {
jbe@173 758 case LUA_TSTRING:
jbe@173 759 // if path key is a string,
jbe@173 760 // check if "current value" is a JSON object (or table without metatable):
jbe@173 761 if (
jbe@173 762 lua_rawequal(L, -1, json_set_objectmt_idx) ||
jbe@173 763 (lua_isnil(L, -1) && lua_type(L, -2) == LUA_TTABLE)
jbe@173 764 ) {
jbe@173 765 // if "current value" is acceptable,
jbe@173 766 // pop metatable and leave "current value" on top of stack:
jbe@173 767 lua_pop(L, 1);
jbe@173 768 } else {
jbe@173 769 // if "current value" is not acceptable:
jbe@173 770 // pop metatable and "current value":
jbe@173 771 lua_pop(L, 2);
jbe@173 772 // throw error if parent element does not exist:
jbe@173 773 if (lua_isnil(L, -1)) return luaL_error(L, "Root element is not a JSON object");
jbe@173 774 // push new JSON object as "current value" onto stack:
jbe@173 775 lua_newtable(L);
jbe@173 776 // create and register shadow table:
jbe@173 777 lua_pushvalue(L, -1);
jbe@173 778 lua_newtable(L);
jbe@173 779 lua_rawset(L, json_set_shadowtbl_idx);
jbe@173 780 // set metatable of JSON object:
jbe@173 781 lua_pushvalue(L, json_set_objectmt_idx);
jbe@173 782 lua_setmetatable(L, -2);
jbe@173 783 // set entry in "parent value":
jbe@173 784 lua_pushvalue(L, idx-1);
jbe@173 785 lua_pushvalue(L, -2);
jbe@173 786 lua_settable(L, -4);
jbe@173 787 }
jbe@173 788 break;
jbe@173 789 case LUA_TNUMBER:
jbe@173 790 // if path key is a number,
jbe@173 791 // check if "current value" is a JSON array (or table without metatable):
jbe@173 792 if (
jbe@173 793 lua_rawequal(L, -1, json_set_arraymt_idx) ||
jbe@173 794 (lua_isnil(L, -1) && lua_type(L, -2) == LUA_TTABLE)
jbe@173 795 ) {
jbe@173 796 // if "current value" is acceptable,
jbe@173 797 // pop metatable and leave "current value" on top of stack:
jbe@173 798 lua_pop(L, 1);
jbe@173 799 } else {
jbe@173 800 // if "current value" is not acceptable:
jbe@173 801 // pop metatable and "current value":
jbe@173 802 lua_pop(L, 2);
jbe@173 803 // throw error if parent element does not exist:
jbe@173 804 if (lua_isnil(L, -1)) return luaL_error(L, "Root element is not a JSON array");
jbe@173 805 // push new JSON array as "current value" onto stack:
jbe@173 806 lua_newtable(L);
jbe@173 807 // create and register shadow table:
jbe@173 808 lua_pushvalue(L, -1);
jbe@173 809 lua_newtable(L);
jbe@173 810 lua_rawset(L, json_set_shadowtbl_idx);
jbe@173 811 // set metatable of JSON array:
jbe@173 812 lua_pushvalue(L, json_set_arraymt_idx);
jbe@173 813 lua_setmetatable(L, -2);
jbe@173 814 // set entry in "parent value":
jbe@173 815 lua_pushvalue(L, idx-1);
jbe@173 816 lua_pushvalue(L, -2);
jbe@173 817 lua_settable(L, -4);
jbe@173 818 }
jbe@173 819 break;
jbe@173 820 default:
jbe@173 821 return luaL_error(L, "Invalid path key of type %s", lua_typename(L, lua_type(L, idx)));
jbe@173 822 }
jbe@173 823 // check if last path element is being processed:
jbe@173 824 if (idx == stacktop) {
jbe@173 825 // if the last path element is being processed,
jbe@173 826 // set last path value in "current value" container:
jbe@173 827 lua_pushvalue(L, idx);
jbe@173 828 lua_pushvalue(L, 2 + json_set_idxshift);
jbe@173 829 lua_settable(L, -3);
jbe@173 830 } else {
jbe@173 831 // if the processed path element is not the last,
jbe@173 832 // use old "current value" as new "parent value"
jbe@173 833 lua_remove(L, -2);
jbe@173 834 // push new "current value" onto stack by performing a lookup:
jbe@173 835 lua_pushvalue(L, idx);
jbe@173 836 lua_gettable(L, -2);
jbe@173 837 }
jbe@173 838 }
jbe@173 839 // return first argument for convenience:
jbe@173 840 lua_settop(L, 1 + json_set_idxshift);
jbe@173 841 return 1;
jbe@173 842 }
jbe@173 843
jbe@147 844 // returns the length of a JSON array (or zero for a table without numeric keys):
jbe@130 845 static int json_len(lua_State *L) {
jbe@147 846 // stack shall contain one function argument:
jbe@130 847 lua_settop(L, 1);
jbe@148 848 // try to get corresponding shadow table for first argument:
jbe@144 849 json_regfetch(L, shadowtbl);
jbe@130 850 lua_pushvalue(L, 1);
jbe@138 851 lua_rawget(L, -2);
jbe@147 852 // if shadow table does not exist, return length of argument, else length of shadow table:
jbe@147 853 lua_pushnumber(L, lua_rawlen(L, lua_isnil(L, -1) ? 1 : -1));
jbe@123 854 return 1;
jbe@123 855 }
jbe@123 856
jbe@175 857 // __index metamethod for JSON objects and JSON arrays:
jbe@130 858 static int json_index(lua_State *L) {
jbe@148 859 // stack shall contain two function arguments:
jbe@130 860 lua_settop(L, 2);
jbe@155 861 // get corresponding shadow table for first argument:
jbe@144 862 json_regfetch(L, shadowtbl);
jbe@130 863 lua_pushvalue(L, 1);
jbe@155 864 lua_rawget(L, -2);
jbe@148 865 // throw error if no shadow table was found:
jbe@139 866 if (lua_isnil(L, -1)) return luaL_error(L, "Shadow table not found");
jbe@148 867 // use key passed as second argument to lookup value in shadow table:
jbe@130 868 lua_pushvalue(L, 2);
jbe@130 869 lua_rawget(L, -2);
jbe@148 870 // if value is null-marker, then push nil onto stack:
jbe@155 871 if (json_isnullmark(L, -1)) lua_pushnil(L);
jbe@148 872 // return either looked up value, or nil
jbe@127 873 return 1;
jbe@127 874 }
jbe@127 875
jbe@175 876 // __newindex metamethod for JSON objects and JSON arrays:
jbe@130 877 static int json_newindex(lua_State *L) {
jbe@148 878 // stack shall contain three function arguments:
jbe@130 879 lua_settop(L, 3);
jbe@148 880 // get corresponding shadow table for first argument:
jbe@144 881 json_regfetch(L, shadowtbl);
jbe@123 882 lua_pushvalue(L, 1);
jbe@143 883 lua_rawget(L, -2);
jbe@148 884 // throw error if no shadow table was found:
jbe@130 885 if (lua_isnil(L, -1)) return luaL_error(L, "Shadow table not found");
jbe@148 886 // replace first argument with shadow table:
jbe@130 887 lua_replace(L, 1);
jbe@148 888 // reset stack and use second and third argument to write to shadow table:
jbe@139 889 lua_settop(L, 3);
jbe@130 890 lua_rawset(L, 1);
jbe@148 891 // return nothing:
jbe@148 892 return 0;
jbe@121 893 }
jbe@121 894
jbe@175 895 // function returned as first value by json_pairs function:
jbe@135 896 static int json_pairs_iterfunc(lua_State *L) {
jbe@149 897 // stack shall contain two function arguments:
jbe@135 898 lua_settop(L, 2);
jbe@155 899 // get corresponding shadow table for first argument:
jbe@144 900 json_regfetch(L, shadowtbl);
jbe@135 901 lua_pushvalue(L, 1);
jbe@155 902 lua_rawget(L, -2);
jbe@149 903 // throw error if no shadow table was found:
jbe@135 904 if (lua_isnil(L, -1)) return luaL_error(L, "Shadow table not found");
jbe@149 905 // get next key value pair from shadow table (using previous key from argument 2)
jbe@149 906 // and return nothing if there is no next pair:
jbe@135 907 lua_pushvalue(L, 2);
jbe@135 908 if (!lua_next(L, -2)) return 0;
jbe@149 909 // replace null-marker with nil:
jbe@155 910 if (json_isnullmark(L, -1)) {
jbe@135 911 lua_pop(L, 1);
jbe@135 912 lua_pushnil(L);
jbe@135 913 }
jbe@149 914 // return key and value (or key and nil, if null-marker was found):
jbe@135 915 return 2;
jbe@135 916 }
jbe@135 917
jbe@149 918 // returns a triple such that 'for key, value in pairs(obj) do ... end'
jbe@175 919 // iterates through all key value pairs (including JSON null values represented as Lua nil):
jbe@135 920 static int json_pairs(lua_State *L) {
jbe@172 921 // require one argument to function
jbe@172 922 luaL_checkany(L, 1);
jbe@149 923 // return triple of function json_pairs_iterfunc, first argument, and nil:
jbe@139 924 lua_pushcfunction(L, json_pairs_iterfunc);
jbe@135 925 lua_pushvalue(L, 1);
jbe@135 926 lua_pushnil(L);
jbe@135 927 return 3;
jbe@135 928 }
jbe@135 929
jbe@175 930 // function returned as first value by json_ipairs function:
jbe@134 931 static int json_ipairs_iterfunc(lua_State *L) {
jbe@152 932 lua_Integer idx;
jbe@149 933 // stack shall contain two function arguments:
jbe@134 934 lua_settop(L, 2);
jbe@149 935 // calculate new index by incrementing second argument:
jbe@134 936 idx = lua_tointeger(L, 2) + 1;
jbe@149 937 // get corresponding shadow table for first argument:
jbe@155 938 json_regfetch(L, shadowtbl);
jbe@134 939 lua_pushvalue(L, 1);
jbe@155 940 lua_rawget(L, -2);
jbe@149 941 // throw error if no shadow table was found:
jbe@134 942 if (lua_isnil(L, -1)) return luaL_error(L, "Shadow table not found");
jbe@149 943 // do integer lookup in shadow table:
jbe@134 944 lua_rawgeti(L, -1, idx);
jbe@149 945 // return nothing if there was no value:
jbe@134 946 if (lua_isnil(L, -1)) return 0;
jbe@149 947 // return new index and
jbe@149 948 // either the looked up value if it is not equal to the null-marker
jbe@149 949 // or nil instead of null-marker:
jbe@134 950 lua_pushinteger(L, idx);
jbe@155 951 if (json_isnullmark(L, -2)) lua_pushnil(L);
jbe@134 952 else lua_pushvalue(L, -2);
jbe@134 953 return 2;
jbe@134 954 }
jbe@134 955
jbe@149 956 // returns a triple such that 'for idx, value in ipairs(ary) do ... end'
jbe@175 957 // iterates through all values (including JSON null values represented as Lua nil):
jbe@134 958 static int json_ipairs(lua_State *L) {
jbe@172 959 // require one argument to function
jbe@172 960 luaL_checkany(L, 1);
jbe@149 961 // return triple of function json_ipairs_iterfunc, first argument, and zero:
jbe@139 962 lua_pushcfunction(L, json_ipairs_iterfunc);
jbe@134 963 lua_pushvalue(L, 1);
jbe@134 964 lua_pushinteger(L, 0);
jbe@134 965 return 3;
jbe@134 966 }
jbe@134 967
jbe@175 968 // datatype representing a table key:
jbe@175 969 // (used for sorting)
jbe@163 970 typedef struct {
jbe@163 971 size_t length;
jbe@163 972 const char *data;
jbe@163 973 } json_key_t;
jbe@163 974
jbe@175 975 // comparation function for table keys to be passed to qsort function:
jbe@163 976 static int json_key_cmp(json_key_t *key1, json_key_t *key2) {
jbe@163 977 size_t pos = 0;
jbe@163 978 unsigned char c1, c2;
jbe@163 979 while (1) {
jbe@163 980 if (key1->length > pos) {
jbe@163 981 if (key2->length > pos) {
jbe@163 982 c1 = key1->data[pos];
jbe@163 983 c2 = key2->data[pos];
jbe@163 984 if (c1 < c2) return -1;
jbe@163 985 else if (c1 > c2) return 1;
jbe@163 986 } else {
jbe@163 987 return 1;
jbe@163 988 }
jbe@163 989 } else {
jbe@163 990 if (key2->length > pos) {
jbe@163 991 return -1;
jbe@163 992 } else {
jbe@163 993 return 0;
jbe@163 994 }
jbe@163 995 }
jbe@163 996 pos++;
jbe@163 997 }
jbe@163 998 }
jbe@163 999
jbe@175 1000 // constants for type detection of ambiguous tables:
jbe@154 1001 #define JSON_TABLETYPE_UNKNOWN 0
jbe@154 1002 #define JSON_TABLETYPE_OBJECT 1
jbe@154 1003 #define JSON_TABLETYPE_ARRAY 2
jbe@154 1004
jbe@175 1005 // special Lua stack indicies for json_export_internal function:
jbe@164 1006 #define json_export_internal_indentstring_idx 1
jbe@164 1007 #define json_export_internal_level_idx 2
jbe@164 1008 #define json_export_internal_value_idx 3
jbe@164 1009 #define json_export_internal_tmp_idx 4
jbe@164 1010
jbe@175 1011 // encodes a JSON document (passed as third argument)
jbe@175 1012 // optionally using indentation (indentation string passed as first argument)
jbe@175 1013 // for a certain depth level (passed as second argument):
jbe@164 1014 static int json_export_internal(lua_State *L) {
jbe@175 1015 int level; // current depth level
jbe@175 1016 int pretty; // pretty printing on? (i.e. printing with indentation)
jbe@175 1017 int i; // iteration variable for level dependent repetitions:
jbe@175 1018 lua_Number num; // number to encode
jbe@175 1019 const char *str; // string to encode
jbe@175 1020 size_t strlen; // length of string to encode
jbe@175 1021 unsigned char c; // character to encode (unsigned!)
jbe@175 1022 size_t pos = 0; // position in string or position of current key (initialized with zero!)
jbe@175 1023 luaL_Buffer buf; // Lua buffer to create strings
jbe@175 1024 char hexcode[7]; // store for unicode hex escape sequence
jbe@175 1025 // NOTE: 7 bytes due to backslash, character 'u', 4 hex digits, and terminating NULL byte
jbe@175 1026 int tabletype = JSON_TABLETYPE_UNKNOWN; // table type: unknown, JSON object, or JSON array
jbe@175 1027 int anyelement = 0; // set to 1 if at least one array element has been processed
jbe@175 1028 size_t keycount = 0; // number of string keys in object
jbe@175 1029 json_key_t *keybuf = NULL; // temporary buffer to store (and sort) string keys of objects
jbe@175 1030 lua_Integer arrayidx; // index to iterate through arrays
jbe@175 1031 // stack shall contain three function arguments:
jbe@164 1032 lua_settop(L, json_export_internal_value_idx);
jbe@175 1033 // if value to encode is the null-marker, then treat it the same as nil:
jbe@164 1034 if (json_isnullmark(L, json_export_internal_value_idx)) {
jbe@164 1035 lua_pop(L, 1);
jbe@157 1036 lua_pushnil(L);
jbe@157 1037 }
jbe@175 1038 // distinguish between different Lua types:
jbe@164 1039 switch (lua_type(L, json_export_internal_value_idx)) {
jbe@175 1040 // value to encode is nil:
jbe@154 1041 case LUA_TNIL:
jbe@175 1042 // return string "null":
jbe@154 1043 lua_pushliteral(L, "null");
jbe@154 1044 return 1;
jbe@175 1045 // value to encode is of type number:
jbe@154 1046 case LUA_TNUMBER:
jbe@175 1047 // convert value to double precision number:
jbe@164 1048 num = lua_tonumber(L, json_export_internal_value_idx);
jbe@175 1049 // throw error if number is not-a-number:
jbe@154 1050 if (isnan(num)) return luaL_error(L, "JSON export not possible for NaN value");
jbe@175 1051 // throw error if number is positive or negative infinity:
jbe@154 1052 if (isinf(num)) return luaL_error(L, "JSON export not possible for infinite numbers");
jbe@175 1053 // return Lua's string encoding of the number:
jbe@164 1054 lua_tostring(L, json_export_internal_value_idx);
jbe@154 1055 return 1;
jbe@175 1056 // value to encode is of type boolean:
jbe@154 1057 case LUA_TBOOLEAN:
jbe@175 1058 // return string "true" or "false" according to boolean value:
jbe@164 1059 if (lua_toboolean(L, json_export_internal_value_idx)) {
jbe@164 1060 lua_pushliteral(L, "true");
jbe@164 1061 } else {
jbe@164 1062 lua_pushliteral(L, "false");
jbe@164 1063 }
jbe@154 1064 return 1;
jbe@175 1065 // value to encode is of type string:
jbe@154 1066 case LUA_TSTRING:
jbe@175 1067 // quote, escape and return string:
jbe@164 1068 str = lua_tolstring(L, 3, &strlen);
jbe@154 1069 luaL_buffinit(L, &buf);
jbe@154 1070 luaL_addchar(&buf, '"');
jbe@154 1071 while (pos < strlen) {
jbe@154 1072 c = str[pos++];
jbe@154 1073 if (c == '"') luaL_addstring(&buf, "\\\"");
jbe@154 1074 else if (c == '\\') luaL_addstring(&buf, "\\\\");
jbe@154 1075 else if (c == 127) luaL_addstring(&buf, "\\u007F");
jbe@154 1076 else if (c >= 32) luaL_addchar(&buf, c);
jbe@154 1077 else if (c == '\b') luaL_addstring(&buf, "\\b");
jbe@154 1078 else if (c == '\f') luaL_addstring(&buf, "\\f");
jbe@154 1079 else if (c == '\n') luaL_addstring(&buf, "\\n");
jbe@154 1080 else if (c == '\r') luaL_addstring(&buf, "\\r");
jbe@154 1081 else if (c == '\t') luaL_addstring(&buf, "\\t");
jbe@154 1082 else if (c == '\v') luaL_addstring(&buf, "\\v");
jbe@154 1083 else {
jbe@154 1084 sprintf(hexcode, "\\u%04X", c);
jbe@154 1085 luaL_addstring(&buf, hexcode);
jbe@154 1086 }
jbe@154 1087 }
jbe@154 1088 luaL_addchar(&buf, '"');
jbe@154 1089 luaL_pushresult(&buf);
jbe@154 1090 return 1;
jbe@175 1091 // value to encode is of type table (this includes JSON objects and JSON arrays):
jbe@154 1092 case LUA_TTABLE:
jbe@175 1093 // use table's metatable to try to determine type of table:
jbe@164 1094 if (lua_getmetatable(L, json_export_internal_value_idx)) {
jbe@154 1095 json_regfetch(L, objectmt);
jbe@154 1096 if (lua_rawequal(L, -2, -1)) {
jbe@154 1097 tabletype = JSON_TABLETYPE_OBJECT;
jbe@154 1098 } else {
jbe@154 1099 json_regfetch(L, arraymt);
jbe@164 1100 if (lua_rawequal(L, -3, -1)) {
jbe@164 1101 tabletype = JSON_TABLETYPE_ARRAY;
jbe@164 1102 } else {
jbe@164 1103 return luaL_error(L, "JSON export not possible for tables with nonsupported metatable");
jbe@164 1104 }
jbe@154 1105 }
jbe@154 1106 }
jbe@175 1107 // replace table with its shadow table if existent, and reset stack:
jbe@154 1108 json_regfetch(L, shadowtbl);
jbe@164 1109 lua_pushvalue(L, json_export_internal_value_idx);
jbe@154 1110 lua_rawget(L, -2);
jbe@164 1111 if (!lua_isnil(L, -1)) lua_replace(L, json_export_internal_value_idx);
jbe@164 1112 lua_settop(L, json_export_internal_value_idx);
jbe@175 1113 // check if type of table is still undetermined:
jbe@154 1114 if (tabletype == JSON_TABLETYPE_UNKNOWN) {
jbe@175 1115 // if yes, iterate over all keys:
jbe@164 1116 for (lua_pushnil(L); lua_next(L, json_export_internal_value_idx); lua_pop(L, 1)) {
jbe@164 1117 switch (lua_type(L, -2)) {
jbe@164 1118 case LUA_TSTRING:
jbe@175 1119 // for string keys,
jbe@175 1120 // increase keycount (may avoid another iteration):
jbe@164 1121 keycount++;
jbe@175 1122 // if type of table was unknown, then type of table is a JSON object now:
jbe@164 1123 if (tabletype == JSON_TABLETYPE_UNKNOWN) tabletype = JSON_TABLETYPE_OBJECT;
jbe@175 1124 // if type of table was a JSON array, then the type of table is ambiguous now
jbe@175 1125 // and an error is thrown:
jbe@164 1126 else if (tabletype == JSON_TABLETYPE_ARRAY) goto json_export_tabletype_error;
jbe@164 1127 break;
jbe@164 1128 case LUA_TNUMBER:
jbe@175 1129 // for numeric keys,
jbe@175 1130 // if type of table was unknown, then type of table is a JSON array now:
jbe@164 1131 if (tabletype == JSON_TABLETYPE_UNKNOWN) tabletype = JSON_TABLETYPE_ARRAY;
jbe@175 1132 // if type of table was a JSON object, then the type of table is ambiguous now
jbe@175 1133 // and an error is thrown:
jbe@164 1134 else if (tabletype == JSON_TABLETYPE_OBJECT) goto json_export_tabletype_error;
jbe@164 1135 break;
jbe@154 1136 }
jbe@154 1137 }
jbe@154 1138 }
jbe@175 1139 // set pretty variable to 1 if pretty printing (with indentation) is desired:
jbe@164 1140 pretty = lua_toboolean(L, json_export_internal_indentstring_idx);
jbe@175 1141 // set level variable to corresponding function argument increased by one:
jbe@164 1142 level = lua_tointeger(L, json_export_internal_level_idx) + 1;
jbe@175 1143 // throw error if there are more levels that could be imported by this library:
jbe@164 1144 if (level > JSON_MAXDEPTH) {
jbe@164 1145 return luaL_error(L, "More than %d nested JSON levels", JSON_MAXDEPTH);
jbe@164 1146 }
jbe@175 1147 // distinguish between JSON objects and JSON arrays:
jbe@154 1148 switch (tabletype) {
jbe@175 1149 // JSON object:
jbe@154 1150 case JSON_TABLETYPE_OBJECT:
jbe@175 1151 // calculate count of string keys unless it has been calculated before:
jbe@164 1152 if (!keycount) {
jbe@164 1153 for (lua_pushnil(L); lua_next(L, json_export_internal_value_idx); lua_pop(L, 1)) {
jbe@164 1154 if (lua_type(L, -2) == LUA_TSTRING) keycount++;
jbe@164 1155 }
jbe@163 1156 }
jbe@175 1157 // create a sorted list of all string keys in memory:
jbe@163 1158 if (keycount) {
jbe@175 1159 // allocate memory for string keys:
jbe@163 1160 keybuf = calloc(keycount, sizeof(json_key_t));
jbe@175 1161 // check if memory allocation was successful:
jbe@175 1162 if (!keybuf) {
jbe@175 1163 // in case of memory exhaustion, try to collect garbage:
jbe@175 1164 lua_gc(L, LUA_GCCOLLECT, 0);
jbe@175 1165 // try to allocate memory again:
jbe@175 1166 keybuf = calloc(keycount, sizeof(json_key_t));
jbe@175 1167 // throw error if memory allocation failed again:
jbe@175 1168 if (!keybuf) {
jbe@175 1169 return luaL_error(L, "Memory allocation failed in JSON library");
jbe@175 1170 }
jbe@175 1171 }
jbe@175 1172 // copy all string keys to the C array:
jbe@164 1173 for (lua_pushnil(L); lua_next(L, json_export_internal_value_idx); lua_pop(L, 1)) {
jbe@163 1174 if (lua_type(L, -2) == LUA_TSTRING) {
jbe@175 1175 json_key_t *key = keybuf + (pos++);
jbe@163 1176 key->data = lua_tolstring(L, -2, &key->length);
jbe@163 1177 }
jbe@163 1178 }
jbe@175 1179 // sort C array using quicksort:
jbe@163 1180 qsort(keybuf, keycount, sizeof(json_key_t), (void *)json_key_cmp);
jbe@163 1181 }
jbe@175 1182 // create Lua string buffer:
jbe@154 1183 luaL_buffinit(L, &buf);
jbe@175 1184 // add opening bracket to output buffer:
jbe@154 1185 luaL_addchar(&buf, '{');
jbe@175 1186 // iterate through all (sorted) string keys:
jbe@175 1187 for (pos=0; pos<keycount; pos++) {
jbe@175 1188 json_key_t *key = keybuf + pos;
jbe@175 1189 // add comma to output buffer unless we process the first key:
jbe@175 1190 if (pos) luaL_addchar(&buf, ',');
jbe@175 1191 // handle indentation for pretty results:
jbe@164 1192 if (pretty) {
jbe@164 1193 luaL_addchar(&buf, '\n');
jbe@164 1194 for (i=0; i<level; i++) {
jbe@164 1195 lua_pushvalue(L, json_export_internal_indentstring_idx);
jbe@164 1196 luaL_addvalue(&buf);
jbe@164 1197 }
jbe@164 1198 }
jbe@175 1199 // recursive call to encode key:
jbe@164 1200 lua_pushcfunction(L, json_export_internal);
jbe@164 1201 lua_pushvalue(L, json_export_internal_indentstring_idx);
jbe@164 1202 lua_pushinteger(L, level);
jbe@163 1203 lua_pushlstring(L, key->data, key->length);
jbe@164 1204 if (lua_pcall(L, 3, 1, 0)) {
jbe@175 1205 // free memory of sorted string keys on error:
jbe@163 1206 if (keybuf) free(keybuf);
jbe@175 1207 // rethrow error:
jbe@163 1208 return lua_error(L);
jbe@154 1209 }
jbe@175 1210 // add encoded key to output buffer:
jbe@163 1211 luaL_addvalue(&buf);
jbe@175 1212 // add colon to output buffer:
jbe@163 1213 luaL_addchar(&buf, ':');
jbe@175 1214 // handle indentation for pretty results:
jbe@164 1215 if (pretty) luaL_addchar(&buf, ' ');
jbe@175 1216 // recursive call to encode value:
jbe@164 1217 lua_pushcfunction(L, json_export_internal);
jbe@164 1218 lua_pushvalue(L, json_export_internal_indentstring_idx);
jbe@164 1219 lua_pushinteger(L, level);
jbe@163 1220 lua_pushlstring(L, key->data, key->length);
jbe@164 1221 lua_rawget(L, json_export_internal_value_idx);
jbe@164 1222 if (lua_pcall(L, 3, 1, 0)) {
jbe@175 1223 // free memory of sorted string keys on error:
jbe@163 1224 if (keybuf) free(keybuf);
jbe@175 1225 // rethrow error:
jbe@163 1226 return lua_error(L);
jbe@163 1227 }
jbe@175 1228 // add encoded value to output buffer:
jbe@163 1229 luaL_addvalue(&buf);
jbe@154 1230 }
jbe@175 1231 // decrement level variable for all following statements:
jbe@175 1232 level--;
jbe@175 1233 // free memory of sorted string keys:
jbe@163 1234 if (keybuf) free(keybuf);
jbe@175 1235 // handle indentation for pretty results:
jbe@164 1236 if (pretty && keycount != 0) {
jbe@164 1237 luaL_addchar(&buf, '\n');
jbe@175 1238 for (i=0; i<level; i++) {
jbe@164 1239 lua_pushvalue(L, json_export_internal_indentstring_idx);
jbe@164 1240 luaL_addvalue(&buf);
jbe@164 1241 }
jbe@164 1242 }
jbe@175 1243 // add closing bracket to output buffer:
jbe@154 1244 luaL_addchar(&buf, '}');
jbe@175 1245 // for pretty results, add final newline character if outermost container is processed:
jbe@175 1246 if (pretty && level == 0) luaL_addchar(&buf, '\n');
jbe@175 1247 // convert and return buffer:
jbe@154 1248 luaL_pushresult(&buf);
jbe@154 1249 return 1;
jbe@175 1250 // JSON array:
jbe@154 1251 case JSON_TABLETYPE_ARRAY:
jbe@175 1252 // reserve an extra element on the stack (needed because Lua buffer has unknown size on stack):
jbe@164 1253 lua_settop(L, json_export_internal_tmp_idx);
jbe@175 1254 // create Lua string buffer:
jbe@154 1255 luaL_buffinit(L, &buf);
jbe@175 1256 // add opening bracket to output buffer:
jbe@154 1257 luaL_addchar(&buf, '[');
jbe@175 1258 // iterate through integer keys:
jbe@175 1259 for (arrayidx = 1; ; arrayidx++) {
jbe@175 1260 // get value in array, and break if nil:
jbe@175 1261 lua_rawgeti(L, json_export_internal_value_idx, arrayidx);
jbe@154 1262 if (lua_isnil(L, -1)) {
jbe@154 1263 lua_pop(L, 1);
jbe@154 1264 break;
jbe@154 1265 }
jbe@175 1266 // store value below Lua string buffer on stack (to allow operation on string buffer):
jbe@164 1267 lua_replace(L, json_export_internal_tmp_idx);
jbe@175 1268 //
jbe@175 1269 // add comma to output buffer unless we process the first element:
jbe@164 1270 if (anyelement) luaL_addchar(&buf, ',');
jbe@175 1271 // remember that we processed an element:
jbe@164 1272 anyelement = 1;
jbe@175 1273 // handle indentation for pretty results:
jbe@164 1274 if (pretty) {
jbe@164 1275 luaL_addchar(&buf, '\n');
jbe@164 1276 for (i=0; i<level; i++) {
jbe@164 1277 lua_pushvalue(L, json_export_internal_indentstring_idx);
jbe@164 1278 luaL_addvalue(&buf);
jbe@164 1279 }
jbe@164 1280 }
jbe@175 1281 // recursive call to encode previously stored value:
jbe@164 1282 lua_pushcfunction(L, json_export_internal);
jbe@164 1283 lua_pushvalue(L, json_export_internal_indentstring_idx);
jbe@164 1284 lua_pushinteger(L, level);
jbe@164 1285 lua_pushvalue(L, json_export_internal_tmp_idx);
jbe@164 1286 lua_call(L, 3, 1);
jbe@175 1287 // add encoded value to output buffer:
jbe@154 1288 luaL_addvalue(&buf);
jbe@154 1289 }
jbe@175 1290 // decrement level variable for all following statements:
jbe@175 1291 level--;
jbe@175 1292 // handle indentation for pretty results:
jbe@164 1293 if (pretty && anyelement) {
jbe@164 1294 luaL_addchar(&buf, '\n');
jbe@175 1295 for (i=0; i<level; i++) {
jbe@164 1296 lua_pushvalue(L, json_export_internal_indentstring_idx);
jbe@164 1297 luaL_addvalue(&buf);
jbe@164 1298 }
jbe@164 1299 }
jbe@175 1300 // add closing bracket to output buffer:
jbe@154 1301 luaL_addchar(&buf, ']');
jbe@175 1302 // for pretty results, add final newline character if outermost container is processed:
jbe@175 1303 if (pretty && level == 0) luaL_addchar(&buf, '\n');
jbe@175 1304 // convert and return buffer:
jbe@154 1305 luaL_pushresult(&buf);
jbe@154 1306 return 1;
jbe@154 1307 }
jbe@175 1308 // throw error if table type is unknown:
jbe@154 1309 json_export_tabletype_error:
jbe@154 1310 return luaL_error(L, "JSON export not possible for ambiguous table (cannot decide whether it is an object or array)");
jbe@154 1311 }
jbe@175 1312 // all other datatypes are considered an error:
jbe@166 1313 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 1314 }
jbe@154 1315
jbe@175 1316 // encodes a JSON document (passed as argument):
jbe@164 1317 static int json_export(lua_State *L) {
jbe@175 1318 // stack shall contain one function argument:
jbe@164 1319 lua_settop(L, 1);
jbe@175 1320 // call json_export_internal function with proper arguments:
jbe@164 1321 lua_pushcfunction(L, json_export_internal);
jbe@164 1322 lua_pushnil(L);
jbe@164 1323 lua_pushinteger(L, 0);
jbe@164 1324 lua_pushvalue(L, 1);
jbe@164 1325 lua_call(L, 3, 1);
jbe@175 1326 // return result:
jbe@164 1327 return 1;
jbe@164 1328 }
jbe@164 1329
jbe@175 1330 // encodes a JSON document (passed as first argument)
jbe@175 1331 // with indentation (indentation string may be passed as second argument):
jbe@164 1332 static int json_pretty(lua_State *L) {
jbe@175 1333 // stack shall contain two function arguments:
jbe@164 1334 lua_settop(L, 2);
jbe@175 1335 // call json_export_internal function with proper arguments:
jbe@164 1336 lua_pushcfunction(L, json_export_internal);
jbe@164 1337 if (lua_isnil(L, 2)) lua_pushliteral(L, " ");
jbe@164 1338 else lua_pushvalue(L, 2);
jbe@164 1339 lua_pushinteger(L, 0);
jbe@164 1340 lua_pushvalue(L, 1);
jbe@164 1341 lua_call(L, 3, 1);
jbe@175 1342 // return result:
jbe@164 1343 return 1;
jbe@164 1344 }
jbe@164 1345
jbe@149 1346 // functions in library module:
jbe@121 1347 static const struct luaL_Reg json_module_functions[] = {
jbe@133 1348 {"object", json_object},
jbe@173 1349 {"array", json_array},
jbe@121 1350 {"import", json_import},
jbe@154 1351 {"export", json_export},
jbe@164 1352 {"pretty", json_pretty},
jbe@173 1353 {"get", json_get},
jbe@173 1354 {"type", json_type},
jbe@173 1355 {"set", json_set},
jbe@121 1356 {NULL, NULL}
jbe@121 1357 };
jbe@121 1358
jbe@149 1359 // metamethods for JSON objects, JSON arrays, and unknown JSON collections (object or array):
jbe@126 1360 static const struct luaL_Reg json_metatable_functions[] = {
jbe@130 1361 {"__len", json_len},
jbe@130 1362 {"__index", json_index},
jbe@130 1363 {"__newindex", json_newindex},
jbe@135 1364 {"__pairs", json_pairs},
jbe@134 1365 {"__ipairs", json_ipairs},
jbe@160 1366 {"__tostring", json_export},
jbe@126 1367 {NULL, NULL}
jbe@126 1368 };
jbe@126 1369
jbe@157 1370 // metamethods for JSON null marker:
jbe@157 1371 static const struct luaL_Reg json_nullmark_metamethods[] = {
jbe@157 1372 {"__tostring", json_nullmark_tostring},
jbe@157 1373 {NULL, NULL}
jbe@157 1374 };
jbe@157 1375
jbe@149 1376 // initializes json library:
jbe@121 1377 int luaopen_json(lua_State *L) {
jbe@149 1378 // empty stack:
jbe@126 1379 lua_settop(L, 0);
jbe@149 1380 // push library module onto stack position 1:
jbe@149 1381 lua_newtable(L);
jbe@149 1382 // register library functions:
jbe@149 1383 luaL_setfuncs(L, json_module_functions, 0);
jbe@149 1384 // create and store objectmt:
jbe@138 1385 lua_newtable(L);
jbe@138 1386 luaL_setfuncs(L, json_metatable_functions, 0);
jbe@144 1387 json_regstore(L, objectmt);
jbe@149 1388 // create and store arraymt:
jbe@138 1389 lua_newtable(L);
jbe@138 1390 luaL_setfuncs(L, json_metatable_functions, 0);
jbe@144 1391 json_regstore(L, arraymt);
jbe@149 1392 // create and store ephemeron table to store shadow tables for each JSON object/array
jbe@149 1393 // to allow NULL values returned as nil
jbe@149 1394 lua_newtable(L);
jbe@138 1395 lua_newtable(L); // metatable for ephemeron table
jbe@121 1396 lua_pushliteral(L, "__mode");
jbe@121 1397 lua_pushliteral(L, "k");
jbe@138 1398 lua_rawset(L, -3);
jbe@138 1399 lua_setmetatable(L, -2);
jbe@144 1400 json_regstore(L, shadowtbl);
jbe@157 1401 // set metatable of null marker and make it available through library module:
jbe@157 1402 json_pushnullmark(L);
jbe@157 1403 lua_newtable(L);
jbe@157 1404 luaL_setfuncs(L, json_nullmark_metamethods, 0);
jbe@157 1405 lua_setmetatable(L, -2);
jbe@157 1406 lua_setfield(L, 1, "null");
jbe@157 1407 // return library module (that's expected on top of stack):
jbe@121 1408 return 1;
jbe@121 1409 }

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