source: box/trunk/lib/common/IOStream.h @ 2439

// --------------------------------------------------------------------------
//
// File
//              Name:    IOStream.h
//              Purpose: I/O Stream abstraction
//              Created: 2003/07/31
//
// --------------------------------------------------------------------------

#ifndef IOSTREAM__H
#define IOSTREAM__H

// --------------------------------------------------------------------------
//
// Class
//              Name:    IOStream
//              Purpose: Abstract interface to streams of data
//              Created: 2003/07/31
//
// --------------------------------------------------------------------------
class IOStream
{
public:
        IOStream();
        virtual ~IOStream();

private:
        IOStream(const IOStream &rToCopy); /* forbidden */
        IOStream& operator=(const IOStream &rToCopy); /* forbidden */
                
public:
        enum
        {
                TimeOutInfinite = -1,
                SizeOfStreamUnknown = -1
        };
        
        enum
        {
                SeekType_Absolute = 0,
                SeekType_Relative = 1,
                SeekType_End = 2
        };
        
        // Timeout in milliseconds
        // Read may return 0 -- does not mean end of stream.
        typedef int64_t pos_type;
        virtual int Read(void *pBuffer, int NBytes, int Timeout = IOStream::TimeOutInfinite) = 0;
        virtual pos_type BytesLeftToRead();     // may return IOStream::SizeOfStreamUnknown (and will for most stream types)
        virtual void Write(const void *pBuffer, int NBytes) = 0;
        virtual void Write(const char *pBuffer);
        virtual void WriteAllBuffered();
        virtual pos_type GetPosition() const;
        virtual void Seek(pos_type Offset, int SeekType);
        virtual void Close();
        
        // Has all data that can be read been read?
        virtual bool StreamDataLeft() = 0;
        // Has the stream been closed (writing not possible)
        virtual bool StreamClosed() = 0;
        
        // Utility functions
        bool ReadFullBuffer(void *pBuffer, int NBytes, int *pNBytesRead, int Timeout = IOStream::TimeOutInfinite);
        bool CopyStreamTo(IOStream &rCopyTo, int Timeout = IOStream::TimeOutInfinite, int BufferSize = 1024);
        void Flush(int Timeout = IOStream::TimeOutInfinite);
        
        static int ConvertSeekTypeToOSWhence(int SeekType);
};


#endif // IOSTREAM__H