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 ;