/mod_couchdb/couchdb/json.lib.lua
Lua | 354 lines | 348 code | 5 blank | 1 comment | 45 complexity | 04ff798c797fadd2cf3677b6714d7310 MD5 | raw file
-
- 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;