vstream.h

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/*
Copyright c1997-2014 Trygve Isaacson. All rights reserved.
This file is part of the Code Vault version 4.1
http://www.bombaydigital.com/
License: MIT. See LICENSE.md in the Vault top level directory.
*/

#ifndef vstream_h
#define vstream_h

#include "vstring.h"

// Allows us to declare our static streamCopy functions here.
class VIOStream;

class VStream {
    public:

        VStream();
        VStream(const VString& name);
        virtual ~VStream() {}

        void readGuaranteed(Vu8* targetBuffer, Vs64 numBytesToRead);
        Vu8 readGuaranteedByte();
        virtual Vs64 read(Vu8* targetBuffer, Vs64 numBytesToRead) = 0;

        virtual Vs64 write(const Vu8* buffer, Vs64 numBytesToWrite) = 0;
        virtual void flush() = 0;

        virtual bool skip(Vs64 numBytesToSkip) = 0;
        virtual bool seek(Vs64 offset, int whence) = 0;
        bool seek0() { return this->seek(0, SEEK_SET); }
        virtual Vs64 getIOOffset() const = 0;
        virtual Vs64 available() const = 0;

        static Vs64 streamCopy(VStream& fromStream, VStream& toStream, Vs64 numBytesToCopy, Vs64 tempBufferSize = 16384);
        static Vs64 streamCopy(VIOStream& fromStream, VIOStream& toStream, Vs64 numBytesToCopy, Vs64 tempBufferSize = 16384);
        static Vs64 streamCopy(VIOStream& fromStream, VStream& toStream, Vs64 numBytesToCopy, Vs64 tempBufferSize = 16384);
        static Vs64 streamCopy(VStream& fromStream, VIOStream& toStream, Vs64 numBytesToCopy, Vs64 tempBufferSize = 16384);

        friend class VWriteBufferedStream;

        const VString& getName() const { return mName; }
        void setName(const VString& name) { mName = name; }

        static bool needSizeConversion(Vs64 sizeValue);
        static void copyMemory(Vu8* toBuffer, const Vu8* fromBuffer, Vs64 numBytesToCopy);
        static Vu8* newNewBuffer(Vs64 bufferSize);
        static Vu8* mallocNewBuffer(Vs64 bufferSize);

    protected:

        /*
        These methods are ONLY overridden by buffer-based subclasses,
        for example VMemoryStream. They are called by the friend function
        streamCopy() so that it can efficiently copy data directly to/from
        streams that have data buffers (namely, VMemoryStream).
        */

        virtual Vu8* _getReadIOPtr() const;
        virtual Vu8* _getWriteIOPtr() const;
        virtual Vs64 _prepareToRead(Vs64 numBytesToRead) const;
        virtual void _prepareToWrite(Vs64 numBytesToWrite);
        virtual void _finishRead(Vs64 numBytesRead);
        virtual void    _finishWrite(Vs64 numBytesWritten);

        VString mName; 
};

#endif /* vstream_h */