--
-- json.lua
--
-- Copyright (c) 2015 rxi
--
-- This library is free software; you can redistribute it and/or modify it
-- under the terms of the MIT license. See LICENSE for details.
--
--
-- LICENSE CONTENTS:
--
-- Copyright (c) 2015 rxi
--
--
-- Permission is hereby granted, free of charge, to any person obtaining a copy of
-- this software and associated documentation files (the "Software"), to deal in
-- the Software without restriction, including without limitation the rights to
-- use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
-- of the Software, and to permit persons to whom the Software is furnished to do
-- so, subject to the following conditions:
--
-- The above copyright notice and this permission notice shall be included in all
-- copies or substantial portions of the Software.
--
-- THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-- IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-- FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-- AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-- LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-- OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-- SOFTWARE.
local json = { _version = "0.1.0" }
-------------------------------------------------------------------------------
-- Encode
-------------------------------------------------------------------------------
local encode
local escape_char_map = {
[ "\\" ] = "\\\\",
[ "\"" ] = "\\\"",
[ "\b" ] = "\\b",
[ "\f" ] = "\\f",
[ "\n" ] = "\\n",
[ "\r" ] = "\\r",
[ "\t" ] = "\\t",
}
local escape_char_map_inv = { [ "\\/" ] = "/" }
for k, v in pairs(escape_char_map) do
escape_char_map_inv[v] = k
end
local function escape_char(c)
return escape_char_map[c] or string.format("\\u%04x", c:byte())
end
local function encode_nil(val)
return "null"
end
local function encode_table(val, stack)
local res = {}
stack = stack or {}
-- Circular reference?
if stack[val] then error("circular reference") end
stack[val] = true
if val[1] ~= nil or next(val) == nil then
-- Treat as array -- check keys are valid and it is not sparse
local n = 0
for k in pairs(val) do
if type(k) ~= "number" then
error("invalid table: mixed or invalid key types")
end
n = n + 1
end
if n ~= #val then
error("invalid table: sparse array")
end
-- Encode
for i, v in ipairs(val) do
table.insert(res, encode(v, stack))
end
stack[val] = nil
return "[" .. table.concat(res, ",") .. "]"
else
-- Treat as an object
for k, v in pairs(val) do
if type(k) ~= "string" then
error("invalid table: mixed or invalid key types")
end
table.insert(res, encode(k, stack) .. ":" .. encode(v, stack))
end
stack[val] = nil
return "{" .. table.concat(res, ",") .. "}"
end
end
local function encode_string(val)
return '"' .. val:gsub('[%z\1-\31\\"]', escape_char) .. '"'
end
local function encode_number(val)
if val ~= val then
return "NaN"
elseif val == math.huge then
return "Infinity"
elseif val == -math.huge then
return "-Infinity"
else
return string.format("%.17g", val)
end
end
local type_func_map = {
[ "nil" ] = encode_nil,
[ "table" ] = encode_table,
[ "string" ] = encode_string,
[ "number" ] = encode_number,
[ "boolean" ] = tostring,
}
encode = function(val, stack)
local t = type(val)
local f = type_func_map[t]
if f then
return f(val, stack)
end
error("unexpected type '" .. t .. "'")
end
return {stringify = function(val) return ( encode(val) ) end}