516 lines
11 KiB
Lua
516 lines
11 KiB
Lua
--[[
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JSON Encoder and Parser for Lua 5.1
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Copyright © 2007 Shaun Brown (http://www.chipmunkav.com).
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All Rights Reserved.
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Permission is hereby granted, free of charge, to any person
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obtaining a copy of this software to deal in the Software without
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restriction, including without limitation the rights to use,
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copy, modify, merge, publish, distribute, sublicense, and/or
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sell copies of the Software, and to permit persons to whom the
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Software is furnished to do so, subject to the following conditions:
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The above copyright notice and this permission notice shall be
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included in all copies or substantial portions of the Software.
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If you find this software useful please give www.chipmunkav.com a mention.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
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OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
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IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR
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ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
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CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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Usage:
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-- Lua script:
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local t = {
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["name1"] = "value1",
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["name2"] = {1, false, true, 23.54, "a \021 string"},
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name3 = Json.Null()
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}
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local json = Json.Encode (t)
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print (json)
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--> {"name1":"value1","name3":null,"name2":[1,false,true,23.54,"a \u0015 string"]}
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local t = Json.Decode(json)
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print(t.name2[4])
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--> 23.54
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Notes:
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1) Encodable Lua types: string, number, boolean, table, nil
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2) Use Json.Null() to insert a null value into a Json object
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3) All control chars are encoded to \uXXXX format eg "\021" encodes to "\u0015"
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4) All Json \uXXXX chars are decoded to chars (0-255 byte range only)
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5) Json single line // and /* */ block comments are discarded during decoding
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6) Numerically indexed Lua arrays are encoded to Json Lists eg [1,2,3]
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7) Lua dictionary tables are converted to Json objects eg {"one":1,"two":2}
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8) Json nulls are decoded to Lua nil and treated by Lua in the normal way
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--]]
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local string = string
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local math = math
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local table = table
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local error = error
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local tonumber = tonumber
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local tostring = tostring
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local type = type
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local setmetatable = setmetatable
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local pairs = pairs
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local ipairs = ipairs
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local assert = assert
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local Chipmunk = Chipmunk
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module("Json")
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local StringBuilder = {
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buffer = {}
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}
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function StringBuilder:New()
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local o = {}
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setmetatable(o, self)
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self.__index = self
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o.buffer = {}
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return o
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end
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function StringBuilder:Append(s)
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self.buffer[#self.buffer+1] = s
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end
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function StringBuilder:ToString()
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return table.concat(self.buffer)
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end
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local JsonWriter = {
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backslashes = {
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['\b'] = "\\b",
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['\t'] = "\\t",
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['\n'] = "\\n",
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['\f'] = "\\f",
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['\r'] = "\\r",
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['"'] = "\\\"",
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['\\'] = "\\\\",
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['/'] = "\\/"
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}
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}
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function JsonWriter:New()
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local o = {}
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o.writer = StringBuilder:New()
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setmetatable(o, self)
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self.__index = self
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return o
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end
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function JsonWriter:Append(s)
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self.writer:Append(s)
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end
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function JsonWriter:ToString()
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return self.writer:ToString()
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end
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function JsonWriter:Write(o)
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local t = type(o)
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if t == "nil" then
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self:WriteNil()
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elseif t == "boolean" then
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self:WriteString(o)
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elseif t == "number" then
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self:WriteString(o)
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elseif t == "string" then
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self:ParseString(o)
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elseif t == "table" then
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self:WriteTable(o)
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elseif t == "function" then
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self:WriteFunction(o)
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elseif t == "thread" then
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self:WriteError(o)
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elseif t == "userdata" then
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self:WriteError(o)
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end
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end
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function JsonWriter:WriteNil()
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self:Append("null")
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end
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function JsonWriter:WriteString(o)
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self:Append(tostring(o))
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end
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function JsonWriter:ParseString(s)
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self:Append('"')
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self:Append(string.gsub(s, "[%z%c\\\"/]", function(n)
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local c = self.backslashes[n]
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if c then return c end
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return string.format("\\u%.4X", string.byte(n))
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end))
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self:Append('"')
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end
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function JsonWriter:IsArray(t)
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local count = 0
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local isindex = function(k)
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if type(k) == "number" and k > 0 then
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if math.floor(k) == k then
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return true
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end
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end
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return false
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end
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for k,v in pairs(t) do
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if not isindex(k) then
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return false, '{', '}'
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else
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count = math.max(count, k)
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end
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end
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return true, '[', ']', count
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end
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function JsonWriter:WriteTable(t)
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local ba, st, et, n = self:IsArray(t)
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self:Append(st)
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if ba then
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for i = 1, n do
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self:Write(t[i])
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if i < n then
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self:Append(',')
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end
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end
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else
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local first = true;
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for k, v in pairs(t) do
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if not first then
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self:Append(',')
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end
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first = false;
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self:ParseString(k)
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self:Append(':')
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self:Write(v)
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end
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end
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self:Append(et)
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end
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function JsonWriter:WriteError(o)
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error(string.format(
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"Encoding of %s unsupported",
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tostring(o)))
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end
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function JsonWriter:WriteFunction(o)
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if o == Null then
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self:WriteNil()
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else
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self:WriteError(o)
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end
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end
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local StringReader = {
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s = "",
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i = 0
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}
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function StringReader:New(s)
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local o = {}
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setmetatable(o, self)
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self.__index = self
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o.s = s or o.s
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return o
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end
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function StringReader:Peek()
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local i = self.i + 1
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if i <= #self.s then
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return string.sub(self.s, i, i)
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end
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return nil
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end
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function StringReader:Next()
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self.i = self.i+1
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if self.i <= #self.s then
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return string.sub(self.s, self.i, self.i)
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end
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return nil
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end
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function StringReader:All()
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return self.s
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end
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local JsonReader = {
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escapes = {
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['t'] = '\t',
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['n'] = '\n',
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['f'] = '\f',
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['r'] = '\r',
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['b'] = '\b',
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}
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}
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function JsonReader:New(s)
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local o = {}
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o.reader = StringReader:New(s)
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setmetatable(o, self)
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self.__index = self
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return o;
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end
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function JsonReader:Read()
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self:SkipWhiteSpace()
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local peek = self:Peek()
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if peek == nil then
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error(string.format(
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"Nil string: '%s'",
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self:All()))
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elseif peek == '{' then
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return self:ReadObject()
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elseif peek == '[' then
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return self:ReadArray()
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elseif peek == '"' then
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return self:ReadString()
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elseif string.find(peek, "[%+%-%d]") then
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return self:ReadNumber()
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elseif peek == 't' then
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return self:ReadTrue()
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elseif peek == 'f' then
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return self:ReadFalse()
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elseif peek == 'n' then
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return self:ReadNull()
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elseif peek == '/' then
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self:ReadComment()
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return self:Read()
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else
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error(string.format(
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"Invalid input: '%s'",
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self:All()))
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end
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end
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function JsonReader:ReadTrue()
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self:TestReservedWord{'t','r','u','e'}
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return true
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end
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function JsonReader:ReadFalse()
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self:TestReservedWord{'f','a','l','s','e'}
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return false
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end
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function JsonReader:ReadNull()
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self:TestReservedWord{'n','u','l','l'}
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return nil
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end
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function JsonReader:TestReservedWord(t)
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for i, v in ipairs(t) do
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if self:Next() ~= v then
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error(string.format(
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"Error reading '%s': %s",
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table.concat(t),
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self:All()))
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end
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end
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end
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function JsonReader:ReadNumber()
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local result = self:Next()
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local peek = self:Peek()
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while peek ~= nil and string.find(
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peek,
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"[%+%-%d%.eE]") do
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result = result .. self:Next()
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peek = self:Peek()
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end
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result = tonumber(result)
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if result == nil then
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error(string.format(
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"Invalid number: '%s'",
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result))
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else
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return result
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end
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end
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function JsonReader:ReadString()
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local result = ""
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assert(self:Next() == '"')
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while self:Peek() ~= '"' do
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local ch = self:Next()
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if ch == '\\' then
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ch = self:Next()
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if self.escapes[ch] then
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ch = self.escapes[ch]
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end
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end
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result = result .. ch
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end
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assert(self:Next() == '"')
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local fromunicode = function(m)
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return string.char(tonumber(m, 16))
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end
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return string.gsub(
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result,
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"u%x%x(%x%x)",
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fromunicode)
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end
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function JsonReader:ReadComment()
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assert(self:Next() == '/')
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local second = self:Next()
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if second == '/' then
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self:ReadSingleLineComment()
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elseif second == '*' then
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self:ReadBlockComment()
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else
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error(string.format(
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"Invalid comment: %s",
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self:All()))
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end
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end
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function JsonReader:ReadBlockComment()
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local done = false
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while not done do
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local ch = self:Next()
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if ch == '*' and self:Peek() == '/' then
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done = true
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end
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if not done and
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ch == '/' and
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self:Peek() == "*" then
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error(string.format(
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"Invalid comment: %s, '/*' illegal.",
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self:All()))
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end
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end
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self:Next()
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end
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function JsonReader:ReadSingleLineComment()
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local ch = self:Next()
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while ch ~= '\r' and ch ~= '\n' do
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ch = self:Next()
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end
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end
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function JsonReader:ReadArray()
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local result = {}
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assert(self:Next() == '[')
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local done = false
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if self:Peek() == ']' then
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done = true;
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end
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while not done do
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local item = self:Read()
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result[#result+1] = item
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self:SkipWhiteSpace()
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if self:Peek() == ']' then
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done = true
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end
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if not done then
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local ch = self:Next()
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if ch ~= ',' then
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error(string.format(
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"Invalid array: '%s' due to: '%s'",
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self:All(), ch))
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end
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end
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end
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assert(']' == self:Next())
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return result
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end
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function JsonReader:ReadObject()
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local result = {}
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assert(self:Next() == '{')
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local done = false
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if self:Peek() == '}' then
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done = true
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end
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while not done do
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local key = self:Read()
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if type(key) ~= "string" then
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error(string.format(
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"Invalid non-string object key: %s",
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key))
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end
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self:SkipWhiteSpace()
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local ch = self:Next()
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if ch ~= ':' then
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error(string.format(
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"Invalid object: '%s' due to: '%s'",
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self:All(),
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ch))
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end
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self:SkipWhiteSpace()
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local val = self:Read()
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result[key] = val
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self:SkipWhiteSpace()
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if self:Peek() == '}' then
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done = true
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end
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if not done then
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ch = self:Next()
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if ch ~= ',' then
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error(string.format(
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"Invalid array: '%s' near: '%s'",
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self:All(),
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ch))
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end
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end
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end
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assert(self:Next() == "}")
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return result
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end
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function JsonReader:SkipWhiteSpace()
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local p = self:Peek()
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while p ~= nil and string.find(p, "[%s/]") do
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if p == '/' then
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self:ReadComment()
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else
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self:Next()
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end
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p = self:Peek()
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end
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end
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function JsonReader:Peek()
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return self.reader:Peek()
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end
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function JsonReader:Next()
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return self.reader:Next()
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end
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function JsonReader:All()
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return self.reader:All()
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end
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function Encode(o)
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local writer = JsonWriter:New()
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writer:Write(o)
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return writer:ToString()
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end
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function Decode(s)
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local reader = JsonReader:New(s)
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return reader:Read()
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end
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function Null()
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return Null
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end
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