sfxMemoryStream.cpp

Detailed Description

  1
  2//-----------------------------------------------------------------------------
  3// Copyright (c) 2012 GarageGames, LLC
  4//
  5// Permission is hereby granted, free of charge, to any person obtaining a copy
  6// of this software and associated documentation files (the "Software"), to
  7// deal in the Software without restriction, including without limitation the
  8// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
  9// sell copies of the Software, and to permit persons to whom the Software is
 10// furnished to do so, subject to the following conditions:
 11//
 12// The above copyright notice and this permission notice shall be included in
 13// all copies or substantial portions of the Software.
 14//
 15// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 16// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 17// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 18// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 19// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 20// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 21// IN THE SOFTWARE.
 22//-----------------------------------------------------------------------------
 23
 24#include "sfx/sfxMemoryStream.h"
 25#include "platform/typetraits.h"
 26#include "console/console.h"
 27
 28
 29SFXMemoryStream::SFXMemoryStream( const SFXFormat& format,
 30                                  SourceStreamType* stream,
 31                                  U32 numSamples )
 32   : IInputStreamFilter< U8, SourceStreamType* >( stream ),
 33     mFormat( format ),
 34     mNumSamplesTotal( numSamples ),
 35     mNumSamplesLeft( numSamples ),
 36     mCurrentPacket( NULL ),
 37     mCurrentPacketOffset( 0 )
 38{
 39}
 40
 41void SFXMemoryStream::reset()
 42{
 43   if( dynamic_cast< IResettable* >( getSourceStream() ) )
 44   {
 45      reinterpret_cast< IResettable* >( getSourceStream() )->reset();
 46      
 47      if( mCurrentPacket )
 48         destructSingle( mCurrentPacket );
 49         
 50      mCurrentPacket = NULL;
 51      mCurrentPacketOffset = 0;
 52      mNumSamplesLeft = mNumSamplesTotal;
 53   }
 54   else
 55      Con::errorf( "SFXMemoryStream - cannot reset source stream" );
 56}
 57
 58U32 SFXMemoryStream::read( U8* buffer, U32 length )
 59{
 60   U32 bufferOffset = 0;
 61   
 62   // Determine how much we're supposed to read.
 63   
 64   U32 numBytesToCopy = length;
 65   if( mNumSamplesLeft != U32_MAX )
 66      numBytesToCopy = getMin( length, mNumSamplesLeft * mFormat.getBytesPerSample() );
 67   numBytesToCopy -= numBytesToCopy % mFormat.getBytesPerSample();
 68      
 69   // Copy the data.
 70   
 71   U32 numBytesLeftToCopy = numBytesToCopy;
 72   while( numBytesLeftToCopy )
 73   {
 74      // If we have a current packet, use its data.
 75      
 76      if( mCurrentPacket )
 77      {
 78         U32 numBytesLeftInCurrentPacket = mCurrentPacket->size - mCurrentPacketOffset;
 79         
 80         // Copy data.
 81         
 82         if( numBytesLeftInCurrentPacket )
 83         {
 84            const U32 remainingNumBytesToCopy = getMin( numBytesLeftInCurrentPacket, numBytesLeftToCopy );
 85            dMemcpy( &buffer[ bufferOffset ], &mCurrentPacket->data[ mCurrentPacketOffset ], remainingNumBytesToCopy);
 86            
 87            bufferOffset                  += remainingNumBytesToCopy;
 88            mCurrentPacketOffset          += remainingNumBytesToCopy;
 89            numBytesLeftInCurrentPacket   -= remainingNumBytesToCopy;
 90            numBytesLeftToCopy            -= remainingNumBytesToCopy;
 91         }
 92         
 93         // Discard the packet if there's no data left.
 94         
 95         if( !numBytesLeftInCurrentPacket )
 96         {
 97            destructSingle( mCurrentPacket );
 98            mCurrentPacket = NULL;
 99            mCurrentPacketOffset = 0;
100         }
101      }
102      else
103      {
104         // Read a new packet.
105         
106         if( !getSourceStream()->read( &mCurrentPacket, 1 ) )
107            break;
108      }
109   }
110   
111   // Update count of remaining samples.
112   
113   U32 numBytesCopied = numBytesToCopy - numBytesLeftToCopy;
114   if( mNumSamplesLeft != U32_MAX )
115      mNumSamplesLeft -= ( numBytesCopied / mFormat.getBytesPerSample() );
116      
117   return numBytesCopied;
118}
119