lua-buffer

AS3 ByteArray class for lua.

usage

add the module:

luaopen_bytearr(L);

constructor

create( [capacity, [endian]] ) - Create an empty byte array. init( [param1, param2, ...] ) - Create a byte array with initial bytes. Parameters should be a list of number or table. load( str ) - Create a byte array with lua string object for read data. This byte array is read-only.

return - A ByteArray object.

local x = ByteArray.create()  -- create an empty byte array
local y = ByteArray.init( 0, 1, 2, 3 ) -- create a byte array with initial bytes
local z = ByteArray.load( "hello" ) -- create a byte array with a lua string object

method for read data

readByte() - Read a 8-bit signed integer from byte array. readUnsignedByte() - Read a 8-bit unsigned integer from byte array. readShort() - Read a 16-bit signed integer from byte array. readUnsignedShort() - Read a 16-bit unsigned integer from byte array. readInt() - Read a 32-bit signed integer from byte array. readUnsignedInt() - Read a 32-bit unsigned integer from byte array. readFloat() - Read a 32-bit float from byte array. readDouble() - Read a 64-bit float from byte array. readCString() - Read a string end with \0 from byte array.

return - A lua number object.

local t = ByteArray.init( 1, 2, 3, 4, 5, 6 ) 
local a = t:readByte() -- a == 1 
local b = t:readUnsignedByte() -- b == 2 
local c = t:readShort() -- c == 0x0403 

method for write data

writeByte( s8 ) - Write a 8-bit signed integer to byte array. writeUnsignedByte( u8 ) - Write a 8-bit unsigned integer to byte array. writeShort( s16 ) - Write a 16-bit signed integer to byte array. writeUnsignedShort( u16 ) - Write a 16-bit unsigned integer to byte array. writeInt( s32 ) - Write a 32-bit signed integer to byte array. writeUnsignedInt( u32 ) - Write a 32-bit unsigned integer to byte array. writeFloat( f32 ) - Write a 32-bit float to byte array. writeDouble( f64 ) - Write a 64-bit float to byte array. writeCString( str ) - write a string end with \0 to byte array.

return - The ByteArray object itself.

local buf = ByteArray.create()
buf:writeByte(1):writeByte(2):writeInt(0x0403)

method for copying data between ByteArray object

readBytes( to[, offset, length] ) - Read data to first parameter(a ByteArray object), the range for the target byte array is start from offset with length. writeBytes( from[, offset, length] ) - Write data from first parameter(a ByteArray object), the range for the data is start from offset with length.

local buf = ByteArray.init( 1, 2, 3, 4, 5 )
local d = ByteArray.create()
buf:readBytes( d )

member position

start position for reading / writing data.

local buf = ByteArray.init( 1, 2, 3, 4, 5 )
buf.position = 3
local d = ByteArray.create()
buf:readBytes( d ) -- buf = <4 5>
print( buf.position ) -- 5

member length

set / get length

local buf = ByteArray.init( 1,2,3,4,5,6,7 )
print( buf.length )
buf.length = 4
for i=1, #buf do print(buf[i]) end

member endian

set / get endian

local buf = ByteArray.init(2,3)
buf.endian = ByteArray.LITTLE_ENDIAN

indexing

index start from 1 to length. If out of range, return -1.

local buf = ByteArray.init(2,3)
print(buf[1])
print(buf[2])