lua/json/util.lua

   1 --[[
   2         Licensed according to the included 'LICENSE' document
   3         Author: Thomas Harning Jr <harningt@gmail.com>
   4 ]]
   5 local type = type
   6 local print = print
   7 local tostring = tostring
   8 local pairs = pairs
   9 local getmetatable, setmetatable = getmetatable, setmetatable
  10 local select = select
  11
  12 local is_52 = _VERSION == "Lua 5.2"
  13 local _G = _G
  14
  15 if is_52 then
  16         _ENV = nil
  17 end
  18
  19 local function foreach(tab, func)
  20         for k, v in pairs(tab) do
  21                 func(k,v)
  22         end
  23 end
  24 local function printValue(tab, name)
  25         local parsed = {}
  26         local function doPrint(key, value, space)
  27                 space = space or ''
  28                 if type(value) == 'table' then
  29                         if parsed[value] then
  30                                 print(space .. key .. '= <' .. parsed[value] .. '>')
  31                         else
  32                                 parsed[value] = key
  33                                 print(space .. key .. '= {')
  34                                 space = space .. ' '
  35                                 foreach(value, function(key, value) doPrint(key, value, space) end)
  36                         end
  37                 else
  38                                         if type(value) == 'string' then
  39                                                 value = '[[' .. tostring(value) .. ']]'
  40                                         end
  41                                         print(space .. key .. '=' .. tostring(value))
  42                 end
  43         end
  44         doPrint(name, tab)
  45 end
  46
  47 local function clone(t)
  48         local ret = {}
  49         for k,v in pairs(t) do
  50                 ret[k] = v
  51         end
  52         return ret
  53 end
  54
  55 local function merge(t, from, ...)
  56         if not from then
  57                 return t
  58         end
  59         for k,v in pairs(from) do
  60                 t[k] = v
  61         end
  62         return merge(t, ...)
  63 end
  64
  65 -- Function to insert nulls into the JSON stream
  66 local function null()
  67         return null
  68 end
  69
  70 -- Marker for 'undefined' values
  71 local function undefined()
  72         return undefined
  73 end
  74
  75 local ArrayMT = {}
  76
  77 --[[
  78         Return's true if the metatable marks it as an array..
  79         Or false if it has no array component at all
  80         Otherwise nil to get the normal detection component working
  81 ]]
  82 local function IsArray(value)
  83         if type(value) ~= 'table' then return false end
  84         local ret = getmetatable(value) == ArrayMT
  85         if not ret then
  86                 if #value == 0 then return false end
  87         else
  88                 return ret
  89         end
  90 end
  91 local function InitArray(array)
  92         setmetatable(array, ArrayMT)
  93         return array
  94 end
  95
  96 local CallMT = {}
  97
  98 local function isCall(value)
  99         return CallMT == getmetatable(value)
 100 end
 101
 102 local function buildCall(name, ...)
 103         local callData = {
 104                 name = name,
 105                 parameters = {n = select('#', ...), ...}
 106         }
 107         return setmetatable(callData, CallMT)
 108 end
 109
 110 local function decodeCall(callData)
 111         if not isCall(callData) then return nil end
 112         return callData.name, callData.parameters
 113 end
 114
 115 local json_util = {
 116         printValue = printValue,
 117         clone = clone,
 118         merge = merge,
 119         null = null,
 120         undefined = undefined,
 121         IsArray = IsArray,
 122         InitArray = InitArray,
 123         isCall = isCall,
 124         buildCall = buildCall,
 125         decodeCall = decodeCall
 126 }
 127
 128 if not is_52 then
 129         _G.json = _G.json or {}
 130         _G.json.util = json_util
 131 end
 132
 133 return json_util