src/json/decode/util.lua

   1 --[[
   2         Licensed according to the included 'LICENSE' document
   3         Author: Thomas Harning Jr <harningt@gmail.com>
   4 ]]
   5 local lpeg = require("lpeg")
   6 local select = select
   7 local pairs, ipairs = pairs, ipairs
   8 local tonumber = tonumber
   9 module("json.decode.util")
  10
  11 space = lpeg.S(" \n\r\t\f")
  12
  13 identifier = lpeg.R("AZ","az","__") * lpeg.R("AZ","az", "__", "09") ^0
  14
  15 hex = lpeg.R("09","AF","af")
  16 hexpair = hex * hex
  17
  18 comments = {
  19         cpp = lpeg.P("//") * (1 - lpeg.P("\n"))^0 * lpeg.P("\n"),
  20         c = lpeg.P("/*") * (1 - lpeg.P("*/"))^0 * lpeg.P("*/")
  21 }
  22
  23 comment = comments.cpp + comments.c
  24
  25 ignored = (space + comment)^0
  26
  27 VALUE, TABLE, ARRAY = 2, 3, 4
  28 function clone(t)
  29         local ret = {}
  30         for k,v in pairs(t) do
  31                 ret[k] = v
  32         end
  33         return ret
  34 end
  35
  36 function merge(t, ...)
  37         for i = 1,select('#', ...) do
  38                 local currentTable = select(i, ...)
  39                 if currentTable then
  40                         for k,v in pairs(currentTable) do
  41                                 t[k] = v
  42                         end
  43                 end
  44         end
  45         return t
  46 end
  47
  48 inits = {}
  49
  50 function doInit()
  51         for _, v in ipairs(inits) do
  52                 v()
  53         end
  54 end
  55
  56 -- Current depth is persistent
  57 -- If more complex depth management needed, a new system would need to be setup
  58 local currentDepth = 0
  59
  60 function buildDepthLimit(limit)
  61         local function init()
  62                 currentDepth = 0
  63         end
  64         inits[#inits + 1] = init
  65
  66         local function incDepth(s, i)
  67                 currentDepth = currentDepth + 1
  68                 return currentDepth < limit and i or false
  69         end
  70         local function decDepth(s, i)
  71                 currentDepth = currentDepth - 1
  72                 return i
  73         end
  74         return {incDepth, decDepth}
  75 end
  76
  77
  78 -- Parse the lpeg version skipping patch-values
  79 -- LPEG <= 0.7 have no version value... so 0.7 is value
  80 DecimalLpegVersion = lpeg.version and tonumber(lpeg.version():match("^(%d+%.%d+)")) or 0.7