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author | Waqas Hussain <waqas20@gmail.com> | 2010-12-27 19:37:04 +0500 |
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committer | Waqas Hussain <waqas20@gmail.com> | 2010-12-27 19:37:04 +0500 |
commit | 82573c9d239937a6d5b7f976f9f149aaa47d0f94 (patch) | |
tree | 4a7f1dbbfd45946bbc2f95254052a12260534ebf /util/json.lua | |
parent | 3043e00706256ba5fd5ab634f37b21e2db9408ee (diff) | |
download | prosody-82573c9d239937a6d5b7f976f9f149aaa47d0f94.tar.gz prosody-82573c9d239937a6d5b7f976f9f149aaa47d0f94.zip |
util.json: Initial commit.
Diffstat (limited to 'util/json.lua')
-rw-r--r-- | util/json.lua | 356 |
1 files changed, 356 insertions, 0 deletions
diff --git a/util/json.lua b/util/json.lua new file mode 100644 index 00000000..40939bb4 --- /dev/null +++ b/util/json.lua @@ -0,0 +1,356 @@ + +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 json = {}; + +local null = newproxy and newproxy(true) or {}; +if getmetatable and getmetatable(null) then + getmetatable(null).__tostring = function() return "null"; end; +end +json.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 json.encode(obj) + local t = {}; + simplesave(obj, t); + return t_concat(t); +end + +----------------------------------- + + +function json.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); + else + error("invalid character at value start: "..ch); + end + end + error("eof while reading value"); + end + next(); + return readvalue(); +end + +function json.test(object) + local encoded = json.encode(object); + local decoded = json.decode(encoded); + local recoded = json.encode(decoded); + if encoded ~= recoded then + print("FAILED"); + print("encoded:", encoded); + print("recoded:", recoded); + else + print(encoded); + end + return encoded == recoded; +end + +return json; |