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/*==LICENSE==*
CyanWorlds.com Engine - MMOG client, server and tools
Copyright (C) 2011 Cyan Worlds, Inc.
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
You can contact Cyan Worlds, Inc. by email legal@cyan.com
or by snail mail at:
Cyan Worlds, Inc.
14617 N Newport Hwy
Mead, WA 99021
*==LICENSE==*/
//////////////////////////////////////////////////////////////////////////////
// //
// plWAVClipBuffer - Helper class for writing out WAV data in a buffered //
// manner, with support for clipping off the specified //
// amount at the end, but without knowing beforehand //
// exactly how much data we'll have. //
// //
// The algorithm goes something like this: we keep two buffers, both the //
// size of the amount we want to clip. We then start filling in the first //
// buffer, overflowing into the second buffer and wrapping back to the //
// first again in a circular fashion. When we fill up one buffer and are //
// about to advance to the next, we write that next buffer out. Why? //
// Because we know that, even if we got no more data in, we have enough //
// data in the first buffer to clip out the amount we want, so the other //
// half (which will have older data, being a circular buffer) can be //
// written out safely. //
// //
//////////////////////////////////////////////////////////////////////////////
#include "hsTypes.h"
#include "plWAVClipBuffer.h"
#include "hsStream.h"
#include "hsUtils.h"
#include "plAudioCore/plWavFile.h"
//// Constructor/Destructor //////////////////////////////////////////////////
plWAVClipBuffer::plWAVClipBuffer( UInt32 clipSize, CWaveFile *outFile )
{
fBuffers[ 0 ] = fBuffers[ 1 ] = nil;
fFlushCalled = true;
Init( clipSize, outFile );
}
plWAVClipBuffer::~plWAVClipBuffer()
{
IShutdown();
}
//// Init & IShutdown ////////////////////////////////////////////////////////
void plWAVClipBuffer::Init( UInt32 clipSize, CWaveFile *outFile )
{
IShutdown();
if( clipSize > 0 )
{
fBuffers[ 0 ] = TRACKED_NEW UInt8[ clipSize ];
fBuffers[ 1 ] = TRACKED_NEW UInt8[ clipSize ];
memset( fBuffers[ 0 ], 0, clipSize );
memset( fBuffers[ 1 ], 0, clipSize );
}
fWhichBuffer = 0;
fBufferSize = clipSize;
fCursor = 0;
fFirstFlip = true;
fOutFile = outFile;
fFlushCalled = false;
}
void plWAVClipBuffer::IShutdown( void )
{
hsAssert( fFlushCalled, "WAVClipBuffer shut down without flushing it!!!" );
delete [] fBuffers[ 0 ];
delete [] fBuffers[ 1 ];
}
//// WriteData ///////////////////////////////////////////////////////////////
// The main workhorse; call this to add data to the buffer.
hsBool plWAVClipBuffer::WriteData( UInt32 size, UInt8 *data )
{
while( size > 0 )
{
UInt32 toWrite = fBufferSize - fCursor;
if( size < toWrite )
{
// Just write, haven't filled a buffer yet
memcpy( fBuffers[ fWhichBuffer ] + fCursor, data, size );
data += size;
fCursor += size;
return true; // All done!
}
// Fill up to the end of a buffer, then flip
memcpy( fBuffers[ fWhichBuffer ] + fCursor, data, toWrite );
data += toWrite;
fCursor += toWrite;
size -= toWrite;
// Flip now...
fWhichBuffer = 1 - fWhichBuffer;
fCursor = 0;
// Now we can write out this buffer, since it'll be old data and
// we have enough in the other buffer to clip with. The *only*
// time we don't want to do this is the first time we flip, since
// at that point, the buffer we just flipped to hasn't been filled yet.
// (Every time afterwards, we'll always be flipping to a buffer with old
// data).
if( fFirstFlip )
fFirstFlip = false;
else
{
// Write it out before we overwrite it!
UINT written;
HRESULT hr = fOutFile->Write( fBufferSize, fBuffers[ fWhichBuffer ], &written );
if( FAILED( hr ) )
{
hsAssert( false, "ERROR writing WMA stream to WAV file" );
return false;
}
else if( written != fBufferSize )
{
hsAssert( false, "Unable to write all of WMA stream to WAV file" );
return false;
}
}
}
// Cleanly got here, so just return success
return true;
}
//// Flush ///////////////////////////////////////////////////////////////////
// Writes out the remaining data, minus our clip value (which is fBufferSize)
// So here's our situation: at this point, one of two things could be true:
//
// 1) We haven't received enough data to clip by, at which point we don't
// write any more and bail (this will be true if fFirstFlip is still true)
//
// 2) Our cursor is at 0, which means we have one filled buffer that hasn't been
// written out and our current buffer is empty. At this point, we discard the
// filled buffer (which is precisely the length we want to clip by) and we're done.
//
// 3) The buffer we're on should be partially filled, while the other one is older
// data. So, we want to write out the older data and the partial buffer all the way,
// except for the clip size. Since we can therefore never write out any data in the
// partial buffer (since that count will always be less than the clip size and thus be
// the second half of what we clip), we simply figure out how much of the other one we
// clip and write out the rest.
hsBool plWAVClipBuffer::Flush( void )
{
fFlushCalled = true;
if( fFirstFlip )
return false; // We failed--not enough data to clip with
if( fCursor == 0 )
{
// Our current buffer is empty, so the other buffer is precisely what we clip.
// So just discard and return successfully
return true;
}
// The hard case--we always discard the partial buffer we're on, so figure out
// how much we want to save of the other buffer. The math is:
// Partial buffer amount we're clipping = fCursor
// Amount of other buffer we're clipping = fBufferSize - fCursor
// Amount of other buffer we're writing = fBufferSize - ( fBufferSize - fCursor ) = fCursor
// Go figure :)
UInt32 toWrite = fCursor;
UINT written;
HRESULT hr = fOutFile->Write( toWrite, fBuffers[ 1 - fWhichBuffer ], &written );
if( FAILED( hr ) )
{
hsAssert( false, "ERROR writing WMA stream to WAV file" );
return false;
}
else if( written != toWrite )
{
hsAssert( false, "Unable to write all of WMA stream to WAV file" );
return false;
}
// All done!
return true;
}