204
+ − 1
+ − 2 local type = type;
+ − 3 local t_insert, t_concat, t_remove = table.insert, table.concat, table.remove;
+ − 4 local s_char = string.char;
+ − 5 local tostring, tonumber = tostring, tonumber;
+ − 6 local pairs, ipairs = pairs, ipairs;
+ − 7 local next = next;
+ − 8 local error = error;
+ − 9 local newproxy, getmetatable = newproxy, getmetatable;
+ − 10 local print = print;
+ − 11
+ − 12 --module("json")
+ − 13 local _M = {};
+ − 14
+ − 15 local null = newproxy and newproxy(true) or {};
+ − 16 if getmetatable and getmetatable(null) then
+ − 17 getmetatable(null).__tostring = function() return "null"; end;
+ − 18 end
+ − 19 _M.null = null;
+ − 20
+ − 21 local escapes = {
+ − 22 ["\""] = "\\\"", ["\\"] = "\\\\", ["\b"] = "\\b",
+ − 23 ["\f"] = "\\f", ["\n"] = "\\n", ["\r"] = "\\r", ["\t"] = "\\t"};
+ − 24 local unescapes = {
+ − 25 ["\""] = "\"", ["\\"] = "\\", ["/"] = "/",
+ − 26 b = "\b", f = "\f", n = "\n", r = "\r", t = "\t"};
+ − 27 for i=0,31 do
+ − 28 local ch = s_char(i);
+ − 29 if not escapes[ch] then escapes[ch] = ("\\u%.4X"):format(i); end
+ − 30 end
+ − 31
+ − 32 local valid_types = {
+ − 33 number = true,
+ − 34 string = true,
+ − 35 table = true,
+ − 36 boolean = true
+ − 37 };
+ − 38 local special_keys = {
+ − 39 __array = true;
+ − 40 __hash = true;
+ − 41 };
+ − 42
+ − 43 local simplesave, tablesave, arraysave, stringsave;
+ − 44
+ − 45 function stringsave(o, buffer)
+ − 46 -- FIXME do proper utf-8 and binary data detection
+ − 47 t_insert(buffer, "\""..(o:gsub(".", escapes)).."\"");
+ − 48 end
+ − 49
+ − 50 function arraysave(o, buffer)
+ − 51 t_insert(buffer, "[");
+ − 52 if next(o) then
+ − 53 for i,v in ipairs(o) do
+ − 54 simplesave(v, buffer);
+ − 55 t_insert(buffer, ",");
+ − 56 end
+ − 57 t_remove(buffer);
+ − 58 end
+ − 59 t_insert(buffer, "]");
+ − 60 end
+ − 61
+ − 62 function tablesave(o, buffer)
+ − 63 local __array = {};
+ − 64 local __hash = {};
+ − 65 local hash = {};
+ − 66 for i,v in ipairs(o) do
+ − 67 __array[i] = v;
+ − 68 end
+ − 69 for k,v in pairs(o) do
+ − 70 local ktype, vtype = type(k), type(v);
+ − 71 if valid_types[vtype] or v == null then
+ − 72 if ktype == "string" and not special_keys[k] then
+ − 73 hash[k] = v;
+ − 74 elseif (valid_types[ktype] or k == null) and __array[k] == nil then
+ − 75 __hash[k] = v;
+ − 76 end
+ − 77 end
+ − 78 end
+ − 79 if next(__hash) ~= nil or next(hash) ~= nil or next(__array) == nil then
+ − 80 t_insert(buffer, "{");
+ − 81 local mark = #buffer;
+ − 82 for k,v in pairs(hash) do
+ − 83 stringsave(k, buffer);
+ − 84 t_insert(buffer, ":");
+ − 85 simplesave(v, buffer);
+ − 86 t_insert(buffer, ",");
+ − 87 end
+ − 88 if next(__hash) ~= nil then
+ − 89 t_insert(buffer, "\"__hash\":[");
+ − 90 for k,v in pairs(__hash) do
+ − 91 simplesave(k, buffer);
+ − 92 t_insert(buffer, ",");
+ − 93 simplesave(v, buffer);
+ − 94 t_insert(buffer, ",");
+ − 95 end
+ − 96 t_remove(buffer);
+ − 97 t_insert(buffer, "]");
+ − 98 t_insert(buffer, ",");
+ − 99 end
+ − 100 if next(__array) then
+ − 101 t_insert(buffer, "\"__array\":");
+ − 102 arraysave(__array, buffer);
+ − 103 t_insert(buffer, ",");
+ − 104 end
+ − 105 if mark ~= #buffer then t_remove(buffer); end
+ − 106 t_insert(buffer, "}");
+ − 107 else
+ − 108 arraysave(__array, buffer);
+ − 109 end
+ − 110 end
+ − 111
+ − 112 function simplesave(o, buffer)
+ − 113 local t = type(o);
+ − 114 if t == "number" then
+ − 115 t_insert(buffer, tostring(o));
+ − 116 elseif t == "string" then
+ − 117 stringsave(o, buffer);
+ − 118 elseif t == "table" then
+ − 119 tablesave(o, buffer);
+ − 120 elseif t == "boolean" then
+ − 121 t_insert(buffer, (o and "true" or "false"));
+ − 122 else
+ − 123 t_insert(buffer, "null");
+ − 124 end
+ − 125 end
+ − 126
+ − 127 function _M.encode(obj)
+ − 128 local t = {};
+ − 129 simplesave(obj, t);
+ − 130 return t_concat(t);
+ − 131 end
+ − 132
+ − 133 -----------------------------------
+ − 134
+ − 135
+ − 136 function _M.decode(json)
+ − 137 local pos = 1;
+ − 138 local current = {};
+ − 139 local stack = {};
+ − 140 local ch, peek;
+ − 141 local function next()
+ − 142 ch = json:sub(pos, pos);
+ − 143 pos = pos+1;
+ − 144 peek = json:sub(pos, pos);
+ − 145 return ch;
+ − 146 end
+ − 147
+ − 148 local function skipwhitespace()
+ − 149 while ch and (ch == "\r" or ch == "\n" or ch == "\t" or ch == " ") do
+ − 150 next();
+ − 151 end
+ − 152 end
+ − 153 local function skiplinecomment()
+ − 154 repeat next(); until not(ch) or ch == "\r" or ch == "\n";
+ − 155 skipwhitespace();
+ − 156 end
+ − 157 local function skipstarcomment()
+ − 158 next(); next(); -- skip '/', '*'
+ − 159 while peek and ch ~= "*" and peek ~= "/" do next(); end
+ − 160 if not peek then error("eof in star comment") end
+ − 161 next(); next(); -- skip '*', '/'
+ − 162 skipwhitespace();
+ − 163 end
+ − 164 local function skipstuff()
+ − 165 while true do
+ − 166 skipwhitespace();
+ − 167 if ch == "/" and peek == "*" then
+ − 168 skipstarcomment();
+ − 169 elseif ch == "/" and peek == "*" then
+ − 170 skiplinecomment();
+ − 171 else
+ − 172 return;
+ − 173 end
+ − 174 end
+ − 175 end
+ − 176
+ − 177 local readvalue;
+ − 178 local function readarray()
+ − 179 local t = {};
+ − 180 next(); -- skip '['
+ − 181 skipstuff();
+ − 182 if ch == "]" then next(); return t; end
+ − 183 t_insert(t, readvalue());
+ − 184 while true do
+ − 185 skipstuff();
+ − 186 if ch == "]" then next(); return t; end
+ − 187 if not ch then error("eof while reading array");
+ − 188 elseif ch == "," then next();
+ − 189 elseif ch then error("unexpected character in array, comma expected"); end
+ − 190 if not ch then error("eof while reading array"); end
+ − 191 t_insert(t, readvalue());
+ − 192 end
+ − 193 end
+ − 194
+ − 195 local function checkandskip(c)
+ − 196 local x = ch or "eof";
+ − 197 if x ~= c then error("unexpected "..x..", '"..c.."' expected"); end
+ − 198 next();
+ − 199 end
+ − 200 local function readliteral(lit, val)
+ − 201 for c in lit:gmatch(".") do
+ − 202 checkandskip(c);
+ − 203 end
+ − 204 return val;
+ − 205 end
+ − 206 local function readstring()
+ − 207 local s = "";
+ − 208 checkandskip("\"");
+ − 209 while ch do
+ − 210 while ch and ch ~= "\\" and ch ~= "\"" do
+ − 211 s = s..ch; next();
+ − 212 end
+ − 213 if ch == "\\" then
+ − 214 next();
+ − 215 if unescapes[ch] then
+ − 216 s = s..unescapes[ch];
+ − 217 next();
+ − 218 elseif ch == "u" then
+ − 219 local seq = "";
+ − 220 for i=1,4 do
+ − 221 next();
+ − 222 if not ch then error("unexpected eof in string"); end
+ − 223 if not ch:match("[0-9a-fA-F]") then error("invalid unicode escape sequence in string"); end
+ − 224 seq = seq..ch;
+ − 225 end
+ − 226 s = s..s.char(tonumber(seq, 16)); -- FIXME do proper utf-8
+ − 227 next();
+ − 228 else error("invalid escape sequence in string"); end
+ − 229 end
+ − 230 if ch == "\"" then
+ − 231 next();
+ − 232 return s;
+ − 233 end
+ − 234 end
+ − 235 error("eof while reading string");
+ − 236 end
+ − 237 local function readnumber()
+ − 238 local s = "";
+ − 239 if ch == "-" then
+ − 240 s = s..ch; next();
+ − 241 if not ch:match("[0-9]") then error("number format error"); end
+ − 242 end
+ − 243 if ch == "0" then
+ − 244 s = s..ch; next();
+ − 245 if ch:match("[0-9]") then error("number format error"); end
+ − 246 else
+ − 247 while ch and ch:match("[0-9]") do
+ − 248 s = s..ch; next();
+ − 249 end
+ − 250 end
+ − 251 if ch == "." then
+ − 252 s = s..ch; next();
+ − 253 if not ch:match("[0-9]") then error("number format error"); end
+ − 254 while ch and ch:match("[0-9]") do
+ − 255 s = s..ch; next();
+ − 256 end
+ − 257 if ch == "e" or ch == "E" then
+ − 258 s = s..ch; next();
+ − 259 if ch == "+" or ch == "-" then
+ − 260 s = s..ch; next();
+ − 261 if not ch:match("[0-9]") then error("number format error"); end
+ − 262 while ch and ch:match("[0-9]") do
+ − 263 s = s..ch; next();
+ − 264 end
+ − 265 end
+ − 266 end
+ − 267 end
+ − 268 return tonumber(s);
+ − 269 end
+ − 270 local function readmember(t)
+ − 271 local k = readstring();
+ − 272 checkandskip(":");
+ − 273 t[k] = readvalue();
+ − 274 end
+ − 275 local function fixobject(obj)
+ − 276 local __array = obj.__array;
+ − 277 if __array then
+ − 278 obj.__array = nil;
+ − 279 for i,v in ipairs(__array) do
+ − 280 t_insert(obj, v);
+ − 281 end
+ − 282 end
+ − 283 local __hash = obj.__hash;
+ − 284 if __hash then
+ − 285 obj.__hash = nil;
+ − 286 local k;
+ − 287 for i,v in ipairs(__hash) do
+ − 288 if k ~= nil then
+ − 289 obj[k] = v; k = nil;
+ − 290 else
+ − 291 k = v;
+ − 292 end
+ − 293 end
+ − 294 end
+ − 295 return obj;
+ − 296 end
+ − 297 local function readobject()
+ − 298 local t = {};
+ − 299 next(); -- skip '{'
+ − 300 skipstuff();
+ − 301 if ch == "}" then next(); return t; end
+ − 302 if not ch then error("eof while reading object"); end
+ − 303 readmember(t);
+ − 304 while true do
+ − 305 skipstuff();
+ − 306 if ch == "}" then next(); return fixobject(t); end
+ − 307 if not ch then error("eof while reading object");
+ − 308 elseif ch == "," then next();
+ − 309 elseif ch then error("unexpected character in object, comma expected"); end
+ − 310 if not ch then error("eof while reading object"); end
+ − 311 readmember(t);
+ − 312 end
+ − 313 end
+ − 314
+ − 315 function readvalue()
+ − 316 skipstuff();
+ − 317 while ch do
+ − 318 if ch == "{" then
+ − 319 return readobject();
+ − 320 elseif ch == "[" then
+ − 321 return readarray();
+ − 322 elseif ch == "\"" then
+ − 323 return readstring();
+ − 324 elseif ch:match("[%-0-9%.]") then
+ − 325 return readnumber();
+ − 326 elseif ch == "n" then
+ − 327 return readliteral("null", null);
+ − 328 elseif ch == "t" then
+ − 329 return readliteral("true", true);
+ − 330 elseif ch == "f" then
+ − 331 return readliteral("false", false);
+ − 332 end
+ − 333 end
+ − 334 error("eof while reading value");
+ − 335 end
+ − 336 next();
+ − 337 return readvalue();
+ − 338 end
+ − 339
+ − 340 function _M.test(object)
+ − 341 local encoded = encode(object);
+ − 342 local decoded = decode(encoded);
+ − 343 local recoded = encode(decoded);
+ − 344 if encoded ~= recoded then
+ − 345 print("FAILED");
+ − 346 print("encoded:", encoded);
+ − 347 print("recoded:", recoded);
+ − 348 else
+ − 349 print(encoded);
+ − 350 end
+ − 351 return encoded ~= recoded;
+ − 352 end
+ − 353
+ − 354 return _M;
