Prosody IM: cd1b73582711 util/json.lua

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prosodyctl: Remove typo'd '+' after LuaRocks 1.x version (thanks spoobie)

author	Matthew Wild <mwild1@gmail.com>
date	Wed, 27 Jul 2011 14:25:05 -0400
parents	7f119ebcf55f
children	5356664ef9d4

line source

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;

12 --module("json")

13 local json = {};

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 json.null = null;

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

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 };

43 local simplesave, tablesave, arraysave, stringsave;

45 function stringsave(o, buffer)

46 -- FIXME do proper utf-8 and binary data detection

47 t_insert(buffer, "\""..(o:gsub(".", escapes)).."\"");

48 end

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

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 json.encode(obj)

128 local t = {};

129 simplesave(obj, t);

130 return t_concat(t);

131 end

132

133 -----------------------------------

134

135

136 function json.decode(json)

137 json = json.." "; -- appending a space ensures valid json wouldn't touch EOF

138 local pos = 1;

139 local current = {};

140 local stack = {};

141 local ch, peek;

142 local function next()

143 ch = json:sub(pos, pos);

144 if ch == "" then error("Unexpected EOF"); end

145 pos = pos+1;

146 peek = json:sub(pos, pos);

147 return ch;

148 end

149

150 local function skipwhitespace()

151 while ch and (ch == "\r" or ch == "\n" or ch == "\t" or ch == " ") do

152 next();

153 end

154 end

155 local function skiplinecomment()

156 repeat next(); until not(ch) or ch == "\r" or ch == "\n";

157 skipwhitespace();

158 end

159 local function skipstarcomment()

160 next(); next(); -- skip '/', '*'

161 while peek and ch ~= "*" and peek ~= "/" do next(); end

162 if not peek then error("eof in star comment") end

163 next(); next(); -- skip '*', '/'

164 skipwhitespace();

165 end

166 local function skipstuff()

167 while true do

168 skipwhitespace();

169 if ch == "/" and peek == "*" then

170 skipstarcomment();

171 elseif ch == "/" and peek == "*" then

172 skiplinecomment();

173 else

174 return;

175 end

176 end

177 end

178

179 local readvalue;

180 local function readarray()

181 local t = {};

182 next(); -- skip '['

183 skipstuff();

184 if ch == "]" then next(); return t; end

185 t_insert(t, readvalue());

186 while true do

187 skipstuff();

188 if ch == "]" then next(); return t; end

189 if not ch then error("eof while reading array");

190 elseif ch == "," then next();

191 elseif ch then error("unexpected character in array, comma expected"); end

192 if not ch then error("eof while reading array"); end

193 t_insert(t, readvalue());

194 end

195 end

196

197 local function checkandskip(c)

198 local x = ch or "eof";

199 if x ~= c then error("unexpected "..x..", '"..c.."' expected"); end

200 next();

201 end

202 local function readliteral(lit, val)

203 for c in lit:gmatch(".") do

204 checkandskip(c);

205 end

206 return val;

207 end

208 local function readstring()

209 local s = "";

210 checkandskip("\"");

211 while ch do

212 while ch and ch ~= "\\" and ch ~= "\"" do

213 s = s..ch; next();

214 end

215 if ch == "\\" then

216 next();

217 if unescapes[ch] then

218 s = s..unescapes[ch];

219 next();

220 elseif ch == "u" then

221 local seq = "";

222 for i=1,4 do

223 next();

224 if not ch then error("unexpected eof in string"); end

225 if not ch:match("[0-9a-fA-F]") then error("invalid unicode escape sequence in string"); end

226 seq = seq..ch;

227 end

228 s = s..s.char(tonumber(seq, 16)); -- FIXME do proper utf-8

229 next();

230 else error("invalid escape sequence in string"); end

231 end

232 if ch == "\"" then

233 next();

234 return s;

235 end

236 end

237 error("eof while reading string");

238 end

239 local function readnumber()

240 local s = "";

241 if ch == "-" then

242 s = s..ch; next();

243 if not ch:match("[0-9]") then error("number format error"); end

244 end

245 if ch == "0" then

246 s = s..ch; next();

247 if ch:match("[0-9]") then error("number format error"); end

248 else

249 while ch and ch:match("[0-9]") do

250 s = s..ch; next();

251 end

252 end

253 if ch == "." then

254 s = s..ch; next();

255 if not ch:match("[0-9]") then error("number format error"); end

256 while ch and ch:match("[0-9]") do

257 s = s..ch; next();

258 end

259 if ch == "e" or ch == "E" then

260 s = s..ch; next();

261 if ch == "+" or ch == "-" then

262 s = s..ch; next();

263 if not ch:match("[0-9]") then error("number format error"); end

264 while ch and ch:match("[0-9]") do

265 s = s..ch; next();

266 end

267 end

268 end

269 end

270 return tonumber(s);

271 end

272 local function readmember(t)

273 skipstuff();

274 local k = readstring();

275 skipstuff();

276 checkandskip(":");

277 t[k] = readvalue();

278 end

279 local function fixobject(obj)

280 local __array = obj.__array;

281 if __array then

282 obj.__array = nil;

283 for i,v in ipairs(__array) do

284 t_insert(obj, v);

285 end

286 end

287 local __hash = obj.__hash;

288 if __hash then

289 obj.__hash = nil;

290 local k;

291 for i,v in ipairs(__hash) do

292 if k ~= nil then

293 obj[k] = v; k = nil;

294 else

295 k = v;

296 end

297 end

298 end

299 return obj;

300 end

301 local function readobject()

302 local t = {};

303 next(); -- skip '{'

304 skipstuff();

305 if ch == "}" then next(); return t; end

306 if not ch then error("eof while reading object"); end

307 readmember(t);

308 while true do

309 skipstuff();

310 if ch == "}" then next(); return fixobject(t); end

311 if not ch then error("eof while reading object");

312 elseif ch == "," then next();

313 elseif ch then error("unexpected character in object, comma expected"); end

314 if not ch then error("eof while reading object"); end

315 readmember(t);

316 end

317 end

318

319 function readvalue()

320 skipstuff();

321 while ch do

322 if ch == "{" then

323 return readobject();

324 elseif ch == "[" then

325 return readarray();

326 elseif ch == "\"" then

327 return readstring();

328 elseif ch:match("[%-0-9%.]") then

329 return readnumber();

330 elseif ch == "n" then

331 return readliteral("null", null);

332 elseif ch == "t" then

333 return readliteral("true", true);

334 elseif ch == "f" then

335 return readliteral("false", false);

336 else

337 error("invalid character at value start: "..ch);

338 end

339 end

340 error("eof while reading value");

341 end

342 next();

343 return readvalue();

344 end

345

346 function json.test(object)

347 local encoded = json.encode(object);

348 local decoded = json.decode(encoded);

349 local recoded = json.encode(decoded);

350 if encoded ~= recoded then

351 print("FAILED");

352 print("encoded:", encoded);

353 print("recoded:", recoded);

354 else

355 print(encoded);

356 end

357 return encoded == recoded;

358 end

359

360 return json;