serialization_in_lua.md

Lua中的字节流序列化

Lua语言并没有为我们提供封装好的字节流序列化库。我们需要动手封装一个类似 JAVA 的 java.nio.ByteBuffer 或 Actionscript 的 flash.utils.ByteArray 的库，方便自己使用。

下面是封装的要点。

1. 依赖库；
2. byte 与 char；
3. 数字；
4. 字符串与中文

这个封装本身的技术难度并不大，因为我们可以依赖极好的库。但实现这个封装，有助于梳理字节流和序列化的相关知识，更帮我复习了一遍 Actionscript 和 JAVA。

local __ba = ByteArrayVarint.new()
__ba:writeByte(0x59)
__ba:writeByte(0x7a)
__ba:writeByte(0)
__ba:writeInt(11)
__ba:writeShort(1101)
__ba:writeByte(0)
__ba:writeByte(3)
__ba:writeByte(bit.bor(0,0))
__ba:writeByte(bit.bor(bit.lshift(1,3), 0))
__ba:writeByte(bit.bor(bit.lshift(2,3), 0))
__ba:writeUVInt(1000)
__ba:writeUVInt(1)
__ba:writeUVInt(1)
__ba:writeStringUVInt("English")
__ba:writeStringUVInt("中文")
__ba:setPos(1)
print(__ba:toString())

print(__ba:readByte())
print(__ba:readByte())
print(__ba:readByte())
print(__ba:readInt())
print(__ba:readShort())
print(__ba:readByte())
print(__ba:readByte())
print(__ba:readByte())
print(__ba:readByte())
print(__ba:readByte())
print(__ba:readUVInt())
print(__ba:readUVInt())
print(__ba:readUVInt())
print(__ba:readStringUVInt())
print(__ba:readStringUVInt())
print(__ba:getAvailable())


local __ba = ByteArray.new()
__ba:writeUByte(66666)
__ba:setPos(1)
print(__ba:getLen())
print(__ba:readByte())
--print(__ba:readByte())
--print(__ba:readByte())
--print(__ba:readByte())

--local __cn = "我是中文我"
--print(__cn)
--print('cn len:', #__cn)
--print("sting.byte cn:", string.byte(__cn, 1, #__cn))
--local __bits = string.pack("<a", __cn)
--print('bits len:', #__bits)
--local __len, __val = string.unpack(__bits, "<a")
--print("unpack bits:", __len, __val)
--print("string.byte bits:", string.byte(__bits, 1, #__bits))
--print("hex bits:", hex(__bits))

local __bits = string.pack("d", 333.666)
local __bits2 = string.pack("f", 333.666)
print("double:" ,string.byte(__bits, 1, #__bits))
print("float:" ,string.byte(__bits2, 1, #__bits2))
print(string.unpack(__bits, "d"))
print(string.unpack( __bits2, "f"))

local __dlong = string.pack("d", 99999999.99)
local __long = string.pack("l", 99999999)
local __ulong = string.pack("L", 99999999)
local __nlong = string.pack("n", 99999999.99)

print("dlong:", #__dlong)
print("dlong:" ,string.byte(__dlong, 1, #__dlong))

print("long:", #__long)
print("long:" ,string.byte(__long, 1, #__long))

print("ulong:", #__ulong)
print("ulong:" ,string.byte(__ulong, 1, #__ulong))

print("nlong:", #__nlong)
print("nlong:" ,string.byte(__nlong, 1, #__nlong))

print("hex", hex(__nlong))
print("hex", hex(__nlong))

local __str = "ABC"
print(#__str)