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/**********
This library is free software; you can redistribute it and/or modify it under
the terms of the GNU Lesser General Public License as published by the
Free Software Foundation; either version 2.1 of the License, or (at your
option) any later version. (See <http://www.gnu.org/copyleft/lesser.html>.)
This library 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 Lesser General Public License for
more details.
You should have received a copy of the GNU Lesser General Public License
along with this library; if not, write to the Free Software Foundation, Inc.,
59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
**********/
// "liveMedia"
// Copyright (c) 1996-2004 Live Networks, Inc. All rights reserved.
// Descriptor preceding frames of 'ADU' MP3 streams (for improved loss-tolerance)
// Implementation
#include "MP3ADUdescriptor.hh"
////////// ADUdescriptor //////////
//##### NOTE: For now, ignore fragmentation. Fix this later! #####
#define TWO_BYTE_DESCR_FLAG 0x40
unsigned ADUdescriptor::generateDescriptor(unsigned char*& toPtr,
unsigned remainingFrameSize) {
unsigned descriptorSize = ADUdescriptor::computeSize(remainingFrameSize);
switch (descriptorSize) {
case 1: {
*toPtr++ = (unsigned char)remainingFrameSize;
break;
}
case 2: {
generateTwoByteDescriptor(toPtr, remainingFrameSize);
break;
}
}
return descriptorSize;
}
void ADUdescriptor::generateTwoByteDescriptor(unsigned char*& toPtr,
unsigned remainingFrameSize) {
*toPtr++ = (TWO_BYTE_DESCR_FLAG|(unsigned char)(remainingFrameSize>>8));
*toPtr++ = (unsigned char)(remainingFrameSize&0xFF);
}
unsigned ADUdescriptor::getRemainingFrameSize(unsigned char*& fromPtr) {
unsigned char firstByte = *fromPtr++;
if (firstByte&TWO_BYTE_DESCR_FLAG) {
// This is a 2-byte descriptor
unsigned char secondByte = *fromPtr++;
return ((firstByte&0x3F)<<8) | secondByte;
} else {
// This is a 1-byte descriptor
return (firstByte&0x3F);
}
}
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