class MemoryStream
{
    virtual void Serialize(void* ioData,
        uint32_t inByteCount) = 0;

    virtual bool IsInput() const = 0;
};
 
class InputMemoryStream: public MemoryStream
{
    ... // 중간 생략
    virtual void Serialize(void* ioData, uint32_t inByteCount)
    {
        Read(ioData, inByteCount);
    }
    virtual bool IsInput() const { return true; }
};
 
class OutputMemoryStream: public MemoryStream
{
    ...// 중간 생략
    virtual void Serialize(void* ioData, uint32_t inByteCount)
    {
        Write(ioData, inByteCount);
    }
    virtual bool IsInput() const { return false; }
}