source: box/trunk/lib/common/MemBlockStream.cpp @ 217

// --------------------------------------------------------------------------
//
// File
//              Name:    MemBlockStream.cpp
//              Purpose: Stream out data from any memory block
//              Created: 2003/09/05
//
// --------------------------------------------------------------------------

#include "Box.h"

#include <string.h>

#include "MemBlockStream.h"
#include "CommonException.h"
#include "StreamableMemBlock.h"
#include "CollectInBufferStream.h"

#include "MemLeakFindOn.h"

// --------------------------------------------------------------------------
//
// Function
//              Name:    MemBlockStream::MemBlockStream()
//              Purpose: Constructor (doesn't copy block, careful with lifetimes)
//              Created: 2003/09/05
//
// --------------------------------------------------------------------------
MemBlockStream::MemBlockStream(const void *pBuffer, int Size)
        : mpBuffer((char*)pBuffer),
          mBytesInBuffer(Size),
          mReadPosition(0)
{
        ASSERT(pBuffer != 0);
        ASSERT(Size >= 0);
}

// --------------------------------------------------------------------------
//
// Function
//              Name:    MemBlockStream::MemBlockStream(const StreamableMemBlock &)
//              Purpose: Constructor (doesn't copy block, careful with lifetimes)
//              Created: 2003/09/05
//
// --------------------------------------------------------------------------
MemBlockStream::MemBlockStream(const StreamableMemBlock &rBlock)
        : mpBuffer((char*)rBlock.GetBuffer()),
          mBytesInBuffer(rBlock.GetSize()),
          mReadPosition(0)
{
        ASSERT(mpBuffer != 0);
        ASSERT(mBytesInBuffer >= 0);
}

// --------------------------------------------------------------------------
//
// Function
//              Name:    MemBlockStream::MemBlockStream(const StreamableMemBlock &)
//              Purpose: Constructor (doesn't copy block, careful with lifetimes)
//              Created: 2003/09/05
//
// --------------------------------------------------------------------------
MemBlockStream::MemBlockStream(const CollectInBufferStream &rBuffer)
        : mpBuffer((char*)rBuffer.GetBuffer()),
          mBytesInBuffer(rBuffer.GetSize()),
          mReadPosition(0)
{
        ASSERT(mpBuffer != 0);
        ASSERT(mBytesInBuffer >= 0);
}


// --------------------------------------------------------------------------
//
// Function
//              Name:    MemBlockStream::MemBlockStream(const MemBlockStream &)
//              Purpose: Copy constructor
//              Created: 2003/09/05
//
// --------------------------------------------------------------------------
MemBlockStream::MemBlockStream(const MemBlockStream &rToCopy)
        : mpBuffer(rToCopy.mpBuffer),
          mBytesInBuffer(rToCopy.mBytesInBuffer),
          mReadPosition(0)
{
        ASSERT(mpBuffer != 0);
        ASSERT(mBytesInBuffer >= 0);
}


// --------------------------------------------------------------------------
//
// Function
//              Name:    MemBlockStream::~MemBlockStream()
//              Purpose: Destructor
//              Created: 2003/09/05
//
// --------------------------------------------------------------------------
MemBlockStream::~MemBlockStream()
{
}

// --------------------------------------------------------------------------
//
// Function
//              Name:    MemBlockStream::Read(void *, int, int)
//              Purpose: As interface. But only works in read phase
//              Created: 2003/09/05
//
// --------------------------------------------------------------------------
int MemBlockStream::Read(void *pBuffer, int NBytes, int Timeout)
{
        // Adjust to number of bytes left
        if(NBytes > (mBytesInBuffer - mReadPosition))
        {
                NBytes = (mBytesInBuffer - mReadPosition);
        }
        ASSERT(NBytes >= 0);
        if(NBytes <= 0) return 0;       // careful now
        
        // Copy in the requested number of bytes and adjust the read pointer
        ::memcpy(pBuffer, mpBuffer + mReadPosition, NBytes);
        mReadPosition += NBytes;
        
        return NBytes;
}

// --------------------------------------------------------------------------
//
// Function
//              Name:    MemBlockStream::BytesLeftToRead()
//              Purpose: As interface. But only works in read phase
//              Created: 2003/09/05
//
// --------------------------------------------------------------------------
IOStream::pos_type MemBlockStream::BytesLeftToRead()
{
        return (mBytesInBuffer - mReadPosition);
}

// --------------------------------------------------------------------------
//
// Function
//              Name:    MemBlockStream::Write(void *, int)
//              Purpose: As interface. But only works in write phase
//              Created: 2003/09/05
//
// --------------------------------------------------------------------------
void MemBlockStream::Write(const void *pBuffer, int NBytes)
{
        THROW_EXCEPTION(CommonException, MemBlockStreamNotSupported)
}

// --------------------------------------------------------------------------
//
// Function
//              Name:    MemBlockStream::GetPosition()
//              Purpose: In write phase, returns the number of bytes written, in read
//                               phase, the number of bytes to go
//              Created: 2003/09/05
//
// --------------------------------------------------------------------------
IOStream::pos_type MemBlockStream::GetPosition() const
{
        return mReadPosition;
}

// --------------------------------------------------------------------------
//
// Function
//              Name:    MemBlockStream::Seek(pos_type, int)
//              Purpose: As interface.
//              Created: 2003/09/05
//
// --------------------------------------------------------------------------
void MemBlockStream::Seek(pos_type Offset, int SeekType)
{
        int newPos = 0;
        switch(SeekType)
        {
        case IOStream::SeekType_Absolute:
                newPos = Offset;
                break;
        case IOStream::SeekType_Relative:
                newPos = mReadPosition + Offset;
                break;
        case IOStream::SeekType_End:
                newPos = mBytesInBuffer + Offset;
                break;
        default:
                THROW_EXCEPTION(CommonException, IOStreamBadSeekType)
                break;
        }
        
        // Make sure it doesn't go over
        if(newPos > mBytesInBuffer)
        {
                newPos = mBytesInBuffer;
        }
        // or under
        if(newPos < 0)
        {
                newPos = 0;
        }
        
        // Set the new read position
        mReadPosition = newPos;
}

// --------------------------------------------------------------------------
//
// Function
//              Name:    MemBlockStream::StreamDataLeft()
//              Purpose: As interface
//              Created: 2003/09/05
//
// --------------------------------------------------------------------------
bool MemBlockStream::StreamDataLeft()
{
        return mReadPosition < mBytesInBuffer;
}

// --------------------------------------------------------------------------
//
// Function
//              Name:    MemBlockStream::StreamClosed()
//              Purpose: As interface
//              Created: 2003/09/05
//
// --------------------------------------------------------------------------
bool MemBlockStream::StreamClosed()
{
        return true;
}