view decoders/libmpg123/getbits.h @ 562:7e08477b0fc1

MP3 decoder upgrade work. Ripped out SMPEG and mpglib support, replaced it with "mpg123.c" and libmpg123. libmpg123 is a much better version of mpglib, so it should solve all the problems about MP3's not seeking, or most modern MP3's not playing at all, etc. Since you no longer have to make a tradeoff with SMPEG for features, and SMPEG is basically rotting, I removed it from the project. There is still work to be done with libmpg123...there are MMX, 3DNow, SSE, Altivec, etc decoders which we don't have enabled at the moment, and the build system could use some work to make this compile more cleanly, etc. Still: huge win.
author Ryan C. Gordon <icculus@icculus.org>
date Fri, 30 Jan 2009 02:44:47 -0500
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/*
	getbits

	copyright ?-2006 by the mpg123 project - free software under the terms of the LGPL 2.1
	see COPYING and AUTHORS files in distribution or http://mpg123.org
	initially written by Michael Hipp
*/

#ifndef _MPG123_GETBITS_H_
#define _MPG123_GETBITS_H_

/* that's the same file as getits.c but with defines to
  force inlining */

#define backbits(fr,nob) ((void)( \
  fr->bitindex    -= nob, \
  fr->wordpointer += (fr->bitindex>>3), \
  fr->bitindex    &= 0x7 ))

#define getbitoffset(fr) ((-fr->bitindex)&0x7)
#define getbyte(fr)      (*fr->wordpointer++)

#define getbits(fr, nob) ( \
  fr->ultmp = fr->wordpointer[0], fr->ultmp <<= 8, fr->ultmp |= fr->wordpointer[1], \
  fr->ultmp <<= 8, fr->ultmp |= fr->wordpointer[2], fr->ultmp <<= fr->bitindex, \
  fr->ultmp &= 0xffffff, fr->bitindex += nob, \
  fr->ultmp >>= (24-nob), fr->wordpointer += (fr->bitindex>>3), \
  fr->bitindex &= 7,fr->ultmp)

#define skipbits(fr, nob) fr->ultmp = ( \
  fr->ultmp = fr->wordpointer[0], fr->ultmp <<= 8, fr->ultmp |= fr->wordpointer[1], \
  fr->ultmp <<= 8, fr->ultmp |= fr->wordpointer[2], fr->ultmp <<= fr->bitindex, \
  fr->ultmp &= 0xffffff, fr->bitindex += nob, \
  fr->ultmp >>= (24-nob), fr->wordpointer += (fr->bitindex>>3), \
  fr->bitindex &= 7 )

#define getbits_fast(fr, nob) ( \
  fr->ultmp = (unsigned char) (fr->wordpointer[0] << fr->bitindex), \
  fr->ultmp |= ((unsigned long) fr->wordpointer[1]<<fr->bitindex)>>8, \
  fr->ultmp <<= nob, fr->ultmp >>= 8, \
  fr->bitindex += nob, fr->wordpointer += (fr->bitindex>>3), \
  fr->bitindex &= 7, fr->ultmp )

#define get1bit(fr) ( \
  fr->uctmp = *fr->wordpointer << fr->bitindex, fr->bitindex++, \
  fr->wordpointer += (fr->bitindex>>3), fr->bitindex &= 7, fr->uctmp>>7 )


#endif