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annotate libraries/json/json.c @ 125:e3e5bf890aad

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Set json.metatable in JSON library for any JSON object/array
author jbe
date Sun Jul 27 01:51:45 2014 +0200 (2014-07-27)
parents ece4e6f683c9
children bccaa05aada7
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@121 5
jbe@125 6 #define JSON_UPVAL_METATABLE lua_upvalueindex(1)
jbe@123 7 #define JSON_UPVAL_NULLS lua_upvalueindex(2)
jbe@125 8 #define JSON_UPVAL_ARYLEN lua_upvalueindex(3)
jbe@123 9
jbe@124 10 #define JSON_STATE_VALUE 0
jbe@124 11 #define JSON_STATE_OBJECT_KEY 1
jbe@124 12 #define JSON_STATE_OBJECT_KEY_TERMINATOR 2
jbe@124 13 #define JSON_STATE_OBJECT_VALUE 3
jbe@124 14 #define JSON_STATE_OBJECT_SEPARATOR 4
jbe@124 15 #define JSON_STATE_ARRAY_VALUE 5
jbe@124 16 #define JSON_STATE_ARRAY_SEPARATOR 6
jbe@124 17 #define JSON_STATE_END 7
jbe@121 18
jbe@121 19 static int json_import(lua_State *L) {
jbe@121 20 const char *str;
jbe@121 21 size_t total;
jbe@121 22 size_t pos = 0;
jbe@121 23 size_t level = 0;
jbe@124 24 int mode = JSON_STATE_VALUE;
jbe@121 25 char c;
jbe@121 26 luaL_Buffer luabuf;
jbe@121 27 char *cbuf;
jbe@121 28 size_t writepos;
jbe@121 29 int aryidx;
jbe@121 30 lua_settop(L, 1);
jbe@121 31 str = lua_tostring(L, 1);
jbe@121 32 total = strlen(str);
jbe@121 33 json_import_loop:
jbe@121 34 while (c = str[pos], c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == '\f') pos++;
jbe@121 35 switch (c) {
jbe@121 36 case 0:
jbe@124 37 if (mode == JSON_STATE_END) return 1;
jbe@121 38 json_import_unexpected_eof:
jbe@121 39 lua_pushnil(L);
jbe@121 40 if (level == 0) lua_pushliteral(L, "Empty string");
jbe@121 41 else lua_pushliteral(L, "Unexpected end of JSON document");
jbe@121 42 return 2;
jbe@121 43 case '{':
jbe@124 44 if (mode != JSON_STATE_VALUE && mode != JSON_STATE_OBJECT_VALUE && mode != JSON_STATE_ARRAY_VALUE)
jbe@121 45 goto json_import_syntax_error;
jbe@121 46 pos++;
jbe@125 47 lua_newtable(L); // the actual JSON object
jbe@125 48 lua_pushvalue(L, JSON_UPVAL_METATABLE);
jbe@125 49 lua_setmetatable(L, -2);
jbe@123 50 lua_newtable(L); // stores set of NULL values
jbe@123 51 lua_pushvalue(L, -2);
jbe@123 52 lua_pushvalue(L, -2);
jbe@123 53 lua_rawset(L, JSON_UPVAL_NULLS);
jbe@124 54 mode = JSON_STATE_OBJECT_KEY;
jbe@121 55 level++;
jbe@121 56 goto json_import_loop;
jbe@121 57 case '[':
jbe@124 58 if (mode != JSON_STATE_VALUE && mode != JSON_STATE_OBJECT_VALUE && mode != JSON_STATE_ARRAY_VALUE)
jbe@121 59 goto json_import_syntax_error;
jbe@121 60 pos++;
jbe@125 61 lua_newtable(L); // the actual JSON array
jbe@125 62 lua_pushvalue(L, JSON_UPVAL_METATABLE);
jbe@125 63 lua_setmetatable(L, -2);
jbe@123 64 lua_newtable(L); // stores set of NULL values
jbe@123 65 lua_pushvalue(L, -2);
jbe@123 66 lua_pushvalue(L, -2);
jbe@123 67 lua_rawset(L, JSON_UPVAL_NULLS);
jbe@121 68 lua_pushinteger(L, 0); // length of array (since it may contain nil's)
jbe@124 69 mode = JSON_STATE_ARRAY_VALUE;
jbe@121 70 level++;
jbe@121 71 goto json_import_loop;
jbe@121 72 case '}':
jbe@124 73 if (mode != JSON_STATE_OBJECT_KEY && mode != JSON_STATE_OBJECT_SEPARATOR)
jbe@121 74 goto json_import_syntax_error;
jbe@121 75 goto json_import_close;
jbe@121 76 case ']':
jbe@124 77 if (mode != JSON_STATE_ARRAY_VALUE && mode != JSON_STATE_ARRAY_SEPARATOR)
jbe@121 78 goto json_import_syntax_error;
jbe@121 79 lua_pushvalue(L, -2); // use array table as key
jbe@121 80 lua_insert(L, -2); // use length of array as value
jbe@123 81 lua_rawset(L, JSON_UPVAL_ARYLEN); // store length in ephemeron table
jbe@121 82 // leaves array table on top of stack
jbe@121 83 json_import_close:
jbe@121 84 pos++;
jbe@123 85 lua_pop(L, 1); // pop table that stores set of NULL values
jbe@121 86 if (--level) {
jbe@121 87 if (lua_type(L, -2) == LUA_TNUMBER) {
jbe@124 88 mode = JSON_STATE_ARRAY_VALUE;
jbe@121 89 } else {
jbe@124 90 mode = JSON_STATE_OBJECT_VALUE;
jbe@121 91 }
jbe@121 92 goto json_import_process_value;
jbe@121 93 } else {
jbe@124 94 mode = JSON_STATE_END;
jbe@121 95 }
jbe@121 96 goto json_import_loop;
jbe@121 97 case ':':
jbe@124 98 if (mode != JSON_STATE_OBJECT_KEY_TERMINATOR)
jbe@121 99 goto json_import_syntax_error;
jbe@121 100 pos++;
jbe@124 101 mode = JSON_STATE_OBJECT_VALUE;
jbe@121 102 goto json_import_loop;
jbe@121 103 case ',':
jbe@124 104 if (mode == JSON_STATE_OBJECT_SEPARATOR) {
jbe@124 105 mode = JSON_STATE_OBJECT_KEY;
jbe@124 106 } else if (mode == JSON_STATE_ARRAY_SEPARATOR) {
jbe@124 107 mode = JSON_STATE_ARRAY_VALUE;
jbe@121 108 } else {
jbe@121 109 goto json_import_syntax_error;
jbe@121 110 }
jbe@121 111 pos++;
jbe@121 112 goto json_import_loop;
jbe@121 113 case '"':
jbe@121 114 cbuf = luaL_buffinitsize(L, &luabuf, total-pos);
jbe@121 115 writepos = 0;
jbe@121 116 pos++;
jbe@121 117 while ((c = str[pos++]) != '"') {
jbe@121 118 if (c == 0) {
jbe@121 119 goto json_import_unexpected_eof;
jbe@121 120 } else if (c < 32 || c == 127) {
jbe@121 121 lua_pushnil(L);
jbe@121 122 lua_pushliteral(L, "Unexpected control character in JSON string");
jbe@121 123 return 2;
jbe@121 124 } else if (c == '\\') {
jbe@121 125 c = str[pos++];
jbe@121 126 switch (c) {
jbe@121 127 case 0:
jbe@121 128 goto json_import_unexpected_eof;
jbe@121 129 case '"':
jbe@121 130 case '/':
jbe@121 131 case '\\':
jbe@121 132 cbuf[writepos++] = c;
jbe@121 133 break;
jbe@121 134 case 'b':
jbe@121 135 cbuf[writepos++] = '\b';
jbe@121 136 break;
jbe@121 137 case 'f':
jbe@121 138 cbuf[writepos++] = '\f';
jbe@121 139 break;
jbe@121 140 case 'n':
jbe@121 141 cbuf[writepos++] = '\n';
jbe@121 142 break;
jbe@121 143 case 'r':
jbe@121 144 cbuf[writepos++] = '\r';
jbe@121 145 break;
jbe@121 146 case 't':
jbe@121 147 cbuf[writepos++] = '\t';
jbe@121 148 break;
jbe@121 149 case 'u':
jbe@121 150 lua_pushnil(L);
jbe@121 151 lua_pushliteral(L, "JSON unicode escape sequences are not implemented yet"); // TODO
jbe@121 152 return 2;
jbe@121 153 default:
jbe@121 154 lua_pushnil(L);
jbe@121 155 lua_pushliteral(L, "Unexpected string escape sequence in JSON document");
jbe@121 156 return 2;
jbe@121 157 }
jbe@121 158 } else {
jbe@121 159 cbuf[writepos++] = c;
jbe@121 160 }
jbe@121 161 }
jbe@121 162 if (!c) goto json_import_unexpected_eof;
jbe@121 163 luaL_pushresultsize(&luabuf, writepos);
jbe@121 164 goto json_import_process_value;
jbe@121 165 }
jbe@122 166 if (c == '-' || (c >= '0' && c <= '9')) {
jbe@122 167 char *endptr;
jbe@122 168 double numval;
jbe@122 169 numval = strtod(str+pos, &endptr);
jbe@122 170 if (endptr == str+pos) goto json_import_syntax_error;
jbe@122 171 pos += endptr - (str+pos);
jbe@122 172 lua_pushnumber(L, numval);
jbe@122 173 } else if (!strncmp(str+pos, "true", 4)) {
jbe@121 174 lua_pushboolean(L, 1);
jbe@121 175 pos += 4;
jbe@121 176 } else if (!strncmp(str+pos, "false", 5)) {
jbe@121 177 lua_pushboolean(L, 0);
jbe@121 178 pos += 5;
jbe@121 179 } else if (!strncmp(str+pos, "null", 4)) {
jbe@121 180 lua_pushnil(L);
jbe@121 181 pos += 4;
jbe@121 182 } else {
jbe@121 183 goto json_import_syntax_error;
jbe@121 184 }
jbe@121 185 json_import_process_value:
jbe@121 186 switch (mode) {
jbe@124 187 case JSON_STATE_OBJECT_KEY:
jbe@121 188 if (lua_type(L, -1) != LUA_TSTRING) goto json_import_syntax_error;
jbe@124 189 mode = JSON_STATE_OBJECT_KEY_TERMINATOR;
jbe@121 190 goto json_import_loop;
jbe@124 191 case JSON_STATE_OBJECT_VALUE:
jbe@123 192 if (lua_isnil(L, -1)) {
jbe@123 193 lua_pushvalue(L, -2);
jbe@123 194 lua_pushboolean(L, 1);
jbe@123 195 lua_rawset(L, -5);
jbe@123 196 }
jbe@123 197 lua_rawset(L, -4);
jbe@124 198 mode = JSON_STATE_OBJECT_SEPARATOR;
jbe@121 199 goto json_import_loop;
jbe@124 200 case JSON_STATE_ARRAY_VALUE:
jbe@121 201 aryidx = lua_tointeger(L, -2) + 1;
jbe@123 202 if (lua_isnil(L, -1)) {
jbe@123 203 lua_pushinteger(L, aryidx);
jbe@123 204 lua_pushboolean(L, 1);
jbe@123 205 lua_rawset(L, -5);
jbe@123 206 }
jbe@123 207 lua_rawseti(L, -4, aryidx);
jbe@121 208 lua_pop(L, 1);
jbe@121 209 lua_pushinteger(L, aryidx);
jbe@124 210 mode = JSON_STATE_ARRAY_SEPARATOR;
jbe@121 211 goto json_import_loop;
jbe@124 212 case JSON_STATE_VALUE:
jbe@124 213 mode = JSON_STATE_END;
jbe@121 214 goto json_import_loop;
jbe@121 215 }
jbe@121 216 json_import_syntax_error:
jbe@121 217 lua_pushnil(L);
jbe@121 218 lua_pushliteral(L, "Syntax error in JSON document");
jbe@121 219 return 2;
jbe@121 220 }
jbe@121 221
jbe@121 222 static int json_arylen(lua_State *L) {
jbe@121 223 lua_settop(L, 1);
jbe@123 224 lua_rawget(L, JSON_UPVAL_ARYLEN);
jbe@123 225 return 1;
jbe@123 226 }
jbe@123 227
jbe@123 228 static int json_isnull(lua_State *L) {
jbe@123 229 lua_pushvalue(L, 1);
jbe@123 230 lua_rawget(L, JSON_UPVAL_NULLS);
jbe@123 231 if (lua_isnil(L, -1)) goto json_isnull_false;
jbe@123 232 lua_pushvalue(L, 2);
jbe@123 233 lua_rawget(L, -2);
jbe@123 234 if (!lua_isnil(L, -1)) return 1;
jbe@123 235 json_isnull_false:
jbe@123 236 lua_pushboolean(L, 0);
jbe@121 237 return 1;
jbe@121 238 }
jbe@121 239
jbe@121 240 static const struct luaL_Reg json_module_functions[] = {
jbe@121 241 {"import", json_import},
jbe@121 242 {"arylen", json_arylen},
jbe@123 243 {"isnull", json_isnull},
jbe@121 244 {NULL, NULL}
jbe@121 245 };
jbe@121 246
jbe@121 247 int luaopen_json(lua_State *L) {
jbe@121 248 lua_newtable(L); // library table
jbe@125 249 lua_newtable(L); // metatable for JSON objects and JSON arrays
jbe@125 250 lua_pushvalue(L, -1);
jbe@125 251 lua_setfield(L, -3, "metatable");
jbe@125 252 lua_newtable(L); // ephemeron table to store a set of keys associated with JSON-null values
jbe@121 253 lua_newtable(L); // ephemeron table to store the length of arrays (that may contain nil's)
jbe@121 254 lua_newtable(L); // meta table for ephemeron table
jbe@121 255 lua_pushliteral(L, "__mode");
jbe@121 256 lua_pushliteral(L, "k");
jbe@121 257 lua_rawset(L, -3);
jbe@123 258 lua_pushvalue(L, -1);
jbe@123 259 lua_setmetatable(L, -3);
jbe@121 260 lua_setmetatable(L, -2);
jbe@125 261 luaL_setfuncs(L, json_module_functions, 3);
jbe@121 262 return 1;
jbe@121 263 }

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