Stream interfaces

IInputStream

An input byte stream. The stream is closed (if necessary) when the interface ptr is deleted

The ReadStream method tries to read numBytesRequested from the stream. Returns the actual number of bytes read which may be less than numBytesRequested, indicating the end of stream. This implies that streams representing I/O (e.g. sockets) must block until numBytesRequested is available. This method must not throw exceptions.

struct IInputStream
{
    virtual ~IInputStream() {}
	virtual ssize_t ReadStream(void* buffer, ssize_t numBytesRequested) = 0;
};

ISeekableInputStream

An input byte stream that allows the current position (relative to the start of the stream) to be get/set.

struct ISeekableInputStream : public IInputStream
{
    // Get the total length of the stream
    virtual ssize_t GetStreamLength() const = 0;

    virtual ssize_t GetStreamPosition() const = 0;
    virtual void SetStreamPosition(ssize_t pos) = 0;
};

IOutputStream

An output byte stream. The stream is closed (if necessary) when the interface ptr is deleted

struct IOutputStream
{
    virtual ~IOutputStream() {}
    virtual void WriteStream(const void* buffer, ssize_t numBytes) = 0;
    virtual void FlushStream() = 0;
};

Closeable streams

These interfaces are used at cross-library boundaries, and in particular where one library gives out a stream to be used by a different library. When the stream is no longer required it must be closed but not deleted by the client! This allows the dlls to employ different heap implementations. It is assumed that closing the stream implicitly deletes it.

ICloseableInputStream

struct ICloseableInputStream : public IInputStream
{
    virtual void Close() = 0;
};

ICloseableSeekableInputStream

struct ICloseableSeekableInputStream : public ISeekableInputStream
{
    virtual void Close() = 0;
};

ICloseableOutputStream

struct ICloseableOutputStream : public IOutputStream
{
    virtual void Close() = 0;
};