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