ffitea.rb

require 'ffi'

module TEA
  extend FFI::Library
  ffi_lib 'tea'
  attach_function :tea_encode, :TEAencode, [:pointer, :uint, :pointer, :pointer, :pointer], :int
  attach_function :tea_decode, :TEAdecode, [:pointer, :uint, :pointer, :pointer, :pointer], :int

  def self.encode(data, key)
    insize = data.bytesize
    inBuf = FFI::MemoryPointer.new(:uchar, insize)
    inBuf.write_string(data, insize)
    keyBuf = FFI::MemoryPointer.new(:uint, 4)
    keyBuf.write_string(key, 16)
    outBuf = FFI::MemoryPointer.new(:char, insize+8)
    outSize = FFI::MemoryPointer.new(:uint, 1)
    outSize.write_uint insize+8
    ret = tea_encode(inBuf,insize,outBuf,outSize,keyBuf)
    (ret == 0) ? outBuf.read_string(outSize.read_uint) : nil
  end

  def self.decode(data, key)
    insize = data.bytesize
    inBuf = FFI::MemoryPointer.new(:uchar, insize)
    inBuf.write_string(data, insize)
    keyBuf = FFI::MemoryPointer.new(:uint, 4)
    keyBuf.write_string(key, 16)
    outBuf = FFI::MemoryPointer.new(:char, insize+8)
    outSize = FFI::MemoryPointer.new(:uint, 1)
    outSize.write_uint insize+8
    ret = tea_decode(inBuf,insize,outBuf,outSize,keyBuf)
    (ret == 0) ? outBuf.read_string(outSize.read_uint) : nil
  end
end