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在lua5.3 使用 zrong 和ByteArray

1. lua 5.3 string.pack 和 string.unpack

http://cloudwu.github.io/lua53doc/manual.html#6.4.2

用于 

string.pack

， 

string.packsize

， 

string.unpack

 的第一個參數。 它是一個描述了需要建立或讀取的結構之布局。

格式串是由轉換選項構成的序列。 這些轉換選項列在後面：

  • <

     : 設為小端編碼

  • >

     : 設為大端編碼

  • =

     : 大小端遵循本地設定

  • ![n]

     : 将最大對齊數設為 

    n

      （預設遵循本地對齊設定）

  • b

     : 一個有符号位元組 (

    char

     )

  • B

     : 一個無符号位元組 (

    char

     )

  • h

     : 一個有符号 

    short

      （本地大小）

  • H

     : 一個無符号 

    short

      （本地大小）

  • l

     : 一個有符号 

    long

      （本地大小）

  • L

     : 一個無符号 

    long

      （本地大小）

  • j

     : 一個 

    lua_Integer

  • J

     : 一個 

    lua_Unsigned

  • T

     : 一個 

    size_t

      （本地大小）

  • i[n]

     : 一個 

    n

      位元組長（預設為本地大小）的有符号 

    int

  • I[n]

     : 一個 

    n

      位元組長（預設為本地大小）的無符号 

    int

  • f

     : 一個 

    float

      （本地大小）

  • d

     : 一個 

    double

      （本地大小）

  • n

     : 一個 

    lua_Number

  • cn

     : 

    n

     位元組固定長度的字元串

  • z

     : 零結尾的字元串

  • s[n]

     : 長度加内容的字元串，其長度編碼為一個 

    n

      位元組（預設是個 

    size_t

     ） 長的無符号整數。

  • x

     : 一個位元組的填充

  • Xop

     : 按選項 

    op

      的方式對齊（忽略它的其它方面）的一個空條目
  • ' ': （空格）忽略

（ "

[n]

" 表示一個可選的整數。） 除填充、空格、配置項（選項 "

xX <=>!

"）外， 每個選項都關聯一個參數（對于 

string.pack

） 或結果（對于 

string.unpack

）。

對于選項 "

!n

", "

sn

", "

in

", "

In

", 

n

 可以是 1 到 16 間的整數。 所有的整數選項都将做溢出檢查； 

string.pack

 檢查提供的值是否能用指定的字長表示； 

string.unpack

 檢查讀出的值能否置入 Lua 整數中。

任何格式串都假設有一個 "

!1=

" 字首， 即最大對齊為 1 （無對齊）且采用本地大小端設定。

對齊行為按如下規則工作： 對每個選項，格式化時都會填充一些位元組直到資料從一個特定偏移處開始， 這個位置是該選項的大小和最大對齊數中較小的那個數的倍數； 這個較小值必須是 2 個整數次方。 選項 "

c

" 及 "

z

" 不做對齊處理； 選項 "

s

" 對對齊遵循其開頭的整數。

string.pack

 用零去填充 （

string.unpack

 則忽略它）。

2. lpack 

http://www.luteus.biz/Download/LoriotPro_Doc/LUA/LUA_For_Windows/lpack/

z

 : zero-terminated string 

p

 : string preceded by length byte 

P

 : string preceded by length word 

a

 : string preceded by length size_t 

A

 : string 

f

 : float 

d

 : double 

n

 : Lua number 

c

 : char 

b

 : byte (unsigned char) 

h

 : short 

H

 : unsigned short 

i

 : int 

I

 : unsigned int 

l

 : long 

L

 : unsigned long

<

 : little endian 

>

 : big endian 

=

 : native endian

3.檢視了lpack和 lua5.3 的string.pack,string.unpack後發現兩者 有些差别

3.1 lpack.pack 的fmt b10 在 string.pack fmt bbbbbbbbbb

3.2 lpack.unpack 和 string.unpack 參數位置不一樣， lpack fmt 在後面， string.pack在前面

3.3 unpack 在5.3移到table下了，是以unpack 修改成 table.unpack

要想使用zrong的ByteArray必需修改

下面是修改後代碼 暫時沒有報錯。主要是 

string.pack 和 string.unpack的修改

--[[
Serialzation bytes stream like ActionScript flash.utils.ByteArray.
It depends on lpack.
A sample: https://github.com/zrong/lua#ByteArray

@see http://underpop.free.fr/l/lua/lpack/
@see http://help.adobe.com/en_US/FlashPlatform/reference/actionscript/3/flash/utils/ByteArray.html
@author zrong(zengrong.net)

Creation 2013-11-14
Last Modification 2014-07-09
]]
local ByteArray = cc.class("ByteArray")

ByteArray.ENDIAN_LITTLE = "ENDIAN_LITTLE"
ByteArray.ENDIAN_BIG = "ENDIAN_BIG"
ByteArray.radix = {[10]="%03u",[8]="%03o",[16]="%02X"}

-- require("pack")

--- Return a string to display.
-- If self is ByteArray, read string from self.
-- Else, treat self as byte string.
-- @param __radix radix of display, value is 8, 10 or 16, default is 10.
-- @param __separator default is " ".
-- @return string, number
function ByteArray.toString(self, __radix, __separator)
	__radix = __radix or 16 
	__radix = ByteArray.radix[__radix] or "%02X"
	__separator = __separator or " "
	local __fmt = __radix..__separator
	local __format = function(__s)
		return string.format(__fmt, string.byte(__s))
	end
	if type(self) == "string" then
		return string.gsub(self, "(.)", __format)
	end
	local __bytes = {}
	for i=1,#self._buf do
		__bytes[i] = __format(self._buf[i])
	end
	return table.concat(__bytes) ,#__bytes
end

function ByteArray:ctor(__endian)
	self._endian = __endian
	self._buf = {}
	self._pos = 1
end

function ByteArray:getLen()
	return #self._buf
end

function ByteArray:getAvailable()
	return #self._buf - self._pos + 1
end

function ByteArray:getPos()
	return self._pos
end

function ByteArray:setPos(__pos)
	self._pos = __pos
	return self
end

function ByteArray:getEndian()
	return self._endian
end

function ByteArray:setEndian(__endian)
	self._endian = __endian
end

--- Get all byte array as a lua string.
-- Do not update position.
function ByteArray:getBytes(__offset, __length)
	__offset = __offset or 1
	__length = __length or #self._buf
	--printf("getBytes,offset:%u, length:%u", __offset, __length)
	return table.concat(self._buf, "", __offset, __length)
end

--- Get pack style string by lpack.
-- The result use ByteArray.getBytes to get is unavailable for lua socket.
-- E.g. the #self:_buf is 18, but #ByteArray.getBytes is 63.
-- I think the cause is the table.concat treat every item in ByteArray._buf as a general string, not a char.
-- So, I use lpack repackage the ByteArray._buf, theretofore, I must convert them to a byte number.
function ByteArray:getPack(__offset, __length)
	__offset = __offset or 1
	__length = __length or #self._buf

	local __fmt = self:_getLC("c" .. (__length - __offset + 1))
	-- print("fmt:", __fmt, #__t)
	local __s = string.pack(__fmt, self:getBytes(__offset, __length))
	return __s
end

--- rawUnPack perform like lpack.pack, but return the ByteArray.
function ByteArray:rawPack(__fmt, ...)
	local __s = string.pack(__fmt, ...)
	self:writeBuf(__s)
	return self
end

--- rawUnPack perform like lpack.unpack, but it is only support FORMAT parameter.
-- Because ByteArray include a position itself, so we haven't to save another.
function ByteArray:rawUnPack(__fmt)
	-- read all of bytes.
	local __s = self:getBytes(self._pos)
	local __next, __val = string.unpack(__fmt, __s)
	-- update position of the ByteArray
	self._pos = self._pos + __next
	-- Alternate value and next
	return __val, __next
end

function ByteArray:readBool()
	-- When char > 256, the readByte method will show an error.
	-- So, we have to use readChar
	return self:readChar() ~= 0
end

function ByteArray:writeBool(__bool)
	if __bool then 
		self:writeByte(1)
	else
		self:writeByte(0)
	end
	return self
end

function ByteArray:readDouble()
	local __v, __ = string.unpack(self:_getLC("d"), self:readBuf(8))
	return __v
end

function ByteArray:writeDouble(__double)
	local __s = string.pack( self:_getLC("d"), __double)
	self:writeBuf(__s)
	return self
end

function ByteArray:readFloat()
	local __v, __ = string.unpack(self:_getLC("f"), self:readBuf(4))
	return __v
end

function ByteArray:writeFloat(__float)
	local __s = string.pack( self:_getLC("f"),  __float)
	self:writeBuf(__s)
	return self
end

function ByteArray:readInt()
	local __v, __ = string.unpack(self:_getLC("i"), self:readBuf(4))
	return __v
end

function ByteArray:writeInt(__int)
	local __s = string.pack( self:_getLC("i"),  __int)
	self:writeBuf(__s)
	return self
end

function ByteArray:readUInt()
	local __v, __ = string.unpack(self:_getLC("I"), self:readBuf(4))
	return __v
end

function ByteArray:writeUInt(__uint)
	local __s = string.pack(self:_getLC("I"), __uint)
	self:writeBuf(__s)
	return self
end

function ByteArray:readShort()
	local __v, __ = string.unpack(self:_getLC("h"), self:readBuf(2))
	return __v
end

function ByteArray:writeShort(__short)
	local __s = string.pack( self:_getLC("h"),  __short)
	self:writeBuf(__s)
	return self
end

function ByteArray:readUShort()
	local __v, __ = string.unpack(self:_getLC("H"), self:readBuf(2))
	return __v
end

function ByteArray:writeUShort(__ushort)
	local __s = string.pack(self:_getLC("H"),  __ushort)
	self:writeBuf(__s)
	return self
end

--[[
-- 2014-07-09 Remove all of methods about Long in ByteArray.
-- @see http://zengrong.net/post/2134.htm
function ByteArray:readLong()
	local __v, __ = string.unpack(self:_getLC("l"), self:readBuf(8))
	return __v
end

function ByteArray:writeLong(__long)
	local __s = string.pack( self:_getLC("l"),  __long)
	self:writeBuf(__s)
	return self
end

function ByteArray:readULong()
	local __v, __ = string.unpack(self:_getLC("L"), self:readBuf(4))
	return __v
end


function ByteArray:writeULong(__ulong)
	local __s = string.pack( self:_getLC("L"), __ulong)
	self:writeBuf(__s)
	return self
end
]]

function ByteArray:readUByte()
	local __v, __al = string.unpack("b", self:readRawByte())
	return __val
end

function ByteArray:writeUByte(__ubyte)
	local __s = string.pack("b", __ubyte)
	self:writeBuf(__s)
	return self
end

function ByteArray:readLuaNumber(__number)
	local __v, __ = string.unpack(self:_getLC("n"), self:readBuf(8))
	return __v
end

function ByteArray:writeLuaNumber(__number)
	local __s = string.pack(self:_getLC("n"), __number)
	self:writeBuf(__s)
	return self
end

--- The differently about (read/write)StringBytes and (read/write)String
-- are use pack libraty or not.
function ByteArray:readStringBytes(__len)
	assert(__len, "Need a length of the string!")
	if __len == 0 then return "" end
	self:_checkAvailable()
	local __v, __ = string.unpack(self:_getLC("A"..__len), self:readBuf(__len))
	return __v
end

function ByteArray:writeStringBytes(__string)
	local __s = string.pack(self:_getLC("A"), __string)
	self:writeBuf(__s)
	return self
end

function ByteArray:readString(__len)
	assert(__len, "Need a length of the string!")
	if __len == 0 then return "" end
	self:_checkAvailable()
	return self:readBuf(__len)
end

function ByteArray:writeString(__string)
	self:writeBuf(__string)
	return self
end

function ByteArray:readStringUInt()
	self:_checkAvailable()
	local __len = self:readUInt()
	return self:readStringBytes(__len)
end

function ByteArray:writeStringUInt(__string)
	self:writeUInt(#__string)
	self:writeStringBytes(__string)
	return self
end

--- The length of size_t in C/C++ is mutable.
-- In 64bit os, it is 8 bytes.
-- In 32bit os, it is 4 bytes.
function ByteArray:readStringSizeT()
	self:_checkAvailable()
	local __s = self:rawUnPack(self:_getLC("a"))
	return  __s
end

--- Perform rawPack() simply.
function ByteArray:writeStringSizeT(__string)
	self:rawPack(self:_getLC("a"), __string)
	return self
end

function ByteArray:readStringUShort()
	self:_checkAvailable()
	local __len = self:readUShort()
	return self:readStringBytes(__len)
end

function ByteArray:writeStringUShort(__string)
	local __s = string.pack(self:_getLC("P"), __string)
	self:writeBuf(__s)
	return self
end

--- Read some bytes from buf
-- @return a bit string
function ByteArray:readBytes(__bytes, __offset, __length)
	assert(cc.iskindof(__bytes, "ByteArray"), "Need a ByteArray instance!")
	local __selfLen = #self._buf
	local __availableLen = __selfLen - self._pos
	__offset = __offset or 1
	if __offset > __selfLen then __offset = 1 end
	__length = __length or 0
	if __length == 0 or __length > __availableLen then __length = __availableLen end
	__bytes:setPos(__offset)
	for i=__offset,__offset+__length do
		__bytes:writeRawByte(self:readRawByte())
	end
end

--- Write some bytes into buf
function ByteArray:writeBytes(__bytes, __offset, __length)
	assert(cc.iskindof(__bytes, "ByteArray"), "Need a ByteArray instance!")
	local __bytesLen = __bytes:getLen()
	if __bytesLen == 0 then return end
	__offset = __offset or 1
	if __offset > __bytesLen then __offset = 1 end
	local __availableLen = __bytesLen - __offset
	__length = __length or __availableLen
	if __length == 0 or __length > __availableLen then __length = __availableLen end
	local __oldPos = __bytes:getPos()
	__bytes:setPos(__offset)
	for i=__offset,__offset+__length do
		self:writeRawByte(__bytes:readRawByte())
	end
	__bytes:setPos(__oldPos)
	return self
end

--- Actionscript3 readByte == lpack readChar
-- A signed char
function ByteArray:readChar()
	local __v, __al = string.unpack("c", self:readRawByte())
	return __val
end

function ByteArray:writeChar(__char)
	self:writeRawByte(string.pack("c", __char))
	return self
end

--- Use the lua string library to get a byte
-- A unsigned char
function ByteArray:readByte()
	return string.byte(self:readRawByte())
end

--- Use the lua string library to write a byte.
-- The byte is a number between 0 and 255, otherwise, the lua will get an error.
function ByteArray:writeByte(__byte)
	self:writeRawByte(string.char(__byte))
	return self
end

function ByteArray:readRawByte()
	self:_checkAvailable()
	local __byte = self._buf[self._pos]
	self._pos = self._pos + 1
	return __byte
end

function ByteArray:writeRawByte(__rawByte)
	if self._pos > #self._buf+1 then
		for i=#self._buf+1,self._pos-1 do
			self._buf[i] = string.char(0)
		end
	end
	self._buf[self._pos] = string.sub(__rawByte, 1,1)
	self._pos = self._pos + 1
	return self
end

--- Read a byte array as string from current position, then update the position.
function ByteArray:readBuf(__len)
	--printf("readBuf,len:%u, pos:%u", __len, self._pos)
	local __ba = self:getBytes(self._pos, self._pos + __len - 1)
	self._pos = self._pos + __len
	return __ba
end

--- Write a encoded char array into buf
function ByteArray:writeBuf(__s)
	for i=1,#__s do
		self:writeRawByte(string.sub(__s,i,i))
	end
	return self
end

----------------------------------------
-- private
----------------------------------------
function ByteArray:_checkAvailable()
	assert(#self._buf >= self._pos, string.format("End of file was encountered. pos: %d, len: %d.", self._pos, #self._buf))
end

--- Get Letter Code
function ByteArray:_getLC(__fmt)
	__fmt = __fmt or ""
	if self._endian == ByteArray.ENDIAN_LITTLE then
		return "<"..__fmt
	elseif self._endian == ByteArray.ENDIAN_BIG then
		return ">"..__fmt
	end
	return "="..__fmt
end

return ByteArray
lua lua5.3 ByteArray
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