local type = type; local t_insert, t_concat, t_remove = table.insert, table.concat, table.remove; local s_char = string.char; local tostring, tonumber = tostring, tonumber; local pairs, ipairs = pairs, ipairs; local next = next; local error = error; local newproxy, getmetatable = newproxy, getmetatable; local print = print; --module("json") local _M = {}; local null = newproxy and newproxy(true) or {}; if getmetatable and getmetatable(null) then getmetatable(null).__tostring = function() return "null"; end; end _M.null = null; local escapes = { ["\""] = "\\\"", ["\\"] = "\\\\", ["\b"] = "\\b", ["\f"] = "\\f", ["\n"] = "\\n", ["\r"] = "\\r", ["\t"] = "\\t"}; local unescapes = { ["\""] = "\"", ["\\"] = "\\", ["/"] = "/", b = "\b", f = "\f", n = "\n", r = "\r", t = "\t"}; for i=0,31 do local ch = s_char(i); if not escapes[ch] then escapes[ch] = ("\\u%.4X"):format(i); end end local valid_types = { number = true, string = true, table = true, boolean = true }; local special_keys = { __array = true; __hash = true; }; local simplesave, tablesave, arraysave, stringsave; function stringsave(o, buffer) -- FIXME do proper utf-8 and binary data detection t_insert(buffer, "\""..(o:gsub(".", escapes)).."\""); end function arraysave(o, buffer) t_insert(buffer, "["); if next(o) then for i,v in ipairs(o) do simplesave(v, buffer); t_insert(buffer, ","); end t_remove(buffer); end t_insert(buffer, "]"); end function tablesave(o, buffer) local __array = {}; local __hash = {}; local hash = {}; for i,v in ipairs(o) do __array[i] = v; end for k,v in pairs(o) do local ktype, vtype = type(k), type(v); if valid_types[vtype] or v == null then if ktype == "string" and not special_keys[k] then hash[k] = v; elseif (valid_types[ktype] or k == null) and __array[k] == nil then __hash[k] = v; end end end if next(__hash) ~= nil or next(hash) ~= nil or next(__array) == nil then t_insert(buffer, "{"); local mark = #buffer; for k,v in pairs(hash) do stringsave(k, buffer); t_insert(buffer, ":"); simplesave(v, buffer); t_insert(buffer, ","); end if next(__hash) ~= nil then t_insert(buffer, "\"__hash\":["); for k,v in pairs(__hash) do simplesave(k, buffer); t_insert(buffer, ","); simplesave(v, buffer); t_insert(buffer, ","); end t_remove(buffer); t_insert(buffer, "]"); t_insert(buffer, ","); end if next(__array) then t_insert(buffer, "\"__array\":"); arraysave(__array, buffer); t_insert(buffer, ","); end if mark ~= #buffer then t_remove(buffer); end t_insert(buffer, "}"); else arraysave(__array, buffer); end end function simplesave(o, buffer) local t = type(o); if t == "number" then t_insert(buffer, tostring(o)); elseif t == "string" then stringsave(o, buffer); elseif t == "table" then tablesave(o, buffer); elseif t == "boolean" then t_insert(buffer, (o and "true" or "false")); else t_insert(buffer, "null"); end end function _M.encode(obj) local t = {}; simplesave(obj, t); return t_concat(t); end ----------------------------------- function _M.decode(json) local pos = 1; local current = {}; local stack = {}; local ch, peek; local function next() ch = json:sub(pos, pos); pos = pos+1; peek = json:sub(pos, pos); return ch; end local function skipwhitespace() while ch and (ch == "\r" or ch == "\n" or ch == "\t" or ch == " ") do next(); end end local function skiplinecomment() repeat next(); until not(ch) or ch == "\r" or ch == "\n"; skipwhitespace(); end local function skipstarcomment() next(); next(); -- skip '/', '*' while peek and ch ~= "*" and peek ~= "/" do next(); end if not peek then error("eof in star comment") end next(); next(); -- skip '*', '/' skipwhitespace(); end local function skipstuff() while true do skipwhitespace(); if ch == "/" and peek == "*" then skipstarcomment(); elseif ch == "/" and peek == "*" then skiplinecomment(); else return; end end end local readvalue; local function readarray() local t = {}; next(); -- skip '[' skipstuff(); if ch == "]" then next(); return t; end t_insert(t, readvalue()); while true do skipstuff(); if ch == "]" then next(); return t; end if not ch then error("eof while reading array"); elseif ch == "," then next(); elseif ch then error("unexpected character in array, comma expected"); end if not ch then error("eof while reading array"); end t_insert(t, readvalue()); end end local function checkandskip(c) local x = ch or "eof"; if x ~= c then error("unexpected "..x..", '"..c.."' expected"); end next(); end local function readliteral(lit, val) for c in lit:gmatch(".") do checkandskip(c); end return val; end local function readstring() local s = ""; checkandskip("\""); while ch do while ch and ch ~= "\\" and ch ~= "\"" do s = s..ch; next(); end if ch == "\\" then next(); if unescapes[ch] then s = s..unescapes[ch]; next(); elseif ch == "u" then local seq = ""; for i=1,4 do next(); if not ch then error("unexpected eof in string"); end if not ch:match("[0-9a-fA-F]") then error("invalid unicode escape sequence in string"); end seq = seq..ch; end s = s..s.char(tonumber(seq, 16)); -- FIXME do proper utf-8 next(); else error("invalid escape sequence in string"); end end if ch == "\"" then next(); return s; end end error("eof while reading string"); end local function readnumber() local s = ""; if ch == "-" then s = s..ch; next(); if not ch:match("[0-9]") then error("number format error"); end end if ch == "0" then s = s..ch; next(); if ch:match("[0-9]") then error("number format error"); end else while ch and ch:match("[0-9]") do s = s..ch; next(); end end if ch == "." then s = s..ch; next(); if not ch:match("[0-9]") then error("number format error"); end while ch and ch:match("[0-9]") do s = s..ch; next(); end if ch == "e" or ch == "E" then s = s..ch; next(); if ch == "+" or ch == "-" then s = s..ch; next(); if not ch:match("[0-9]") then error("number format error"); end while ch and ch:match("[0-9]") do s = s..ch; next(); end end end end return tonumber(s); end local function readmember(t) local k = readstring(); checkandskip(":"); t[k] = readvalue(); end local function fixobject(obj) local __array = obj.__array; if __array then obj.__array = nil; for i,v in ipairs(__array) do t_insert(obj, v); end end local __hash = obj.__hash; if __hash then obj.__hash = nil; local k; for i,v in ipairs(__hash) do if k ~= nil then obj[k] = v; k = nil; else k = v; end end end return obj; end local function readobject() local t = {}; next(); -- skip '{' skipstuff(); if ch == "}" then next(); return t; end if not ch then error("eof while reading object"); end readmember(t); while true do skipstuff(); if ch == "}" then next(); return fixobject(t); end if not ch then error("eof while reading object"); elseif ch == "," then next(); elseif ch then error("unexpected character in object, comma expected"); end if not ch then error("eof while reading object"); end readmember(t); end end function readvalue() skipstuff(); while ch do if ch == "{" then return readobject(); elseif ch == "[" then return readarray(); elseif ch == "\"" then return readstring(); elseif ch:match("[%-0-9%.]") then return readnumber(); elseif ch == "n" then return readliteral("null", null); elseif ch == "t" then return readliteral("true", true); elseif ch == "f" then return readliteral("false", false); end end error("eof while reading value"); end next(); return readvalue(); end function _M.test(object) local encoded = encode(object); local decoded = decode(encoded); local recoded = encode(decoded); if encoded ~= recoded then print("FAILED"); print("encoded:", encoded); print("recoded:", recoded); else print(encoded); end return encoded ~= recoded; end return _M;