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/* putbits.c, bit-level output */
/* Copyright (C) 1996, MPEG Software Simulation Group. All Rights Reserved. */
/*
* Disclaimer of Warranty
*
* These software programs are available to the user without any license fee or
* royalty on an "as is" basis. The MPEG Software Simulation Group disclaims
* any and all warranties, whether express, implied, or statuary, including any
* implied warranties or merchantability or of fitness for a particular
* purpose. In no event shall the copyright-holder be liable for any
* incidental, punitive, or consequential damages of any kind whatsoever
* arising from the use of these programs.
*
* This disclaimer of warranty extends to the user of these programs and user's
* customers, employees, agents, transferees, successors, and assigns.
*
* The MPEG Software Simulation Group does not represent or warrant that the
* programs furnished hereunder are free of infringement of any third-party
* patents.
*
* Commercial implementations of MPEG-1 and MPEG-2 video, including shareware,
* are subject to royalty fees to patent holders. Many of these patents are
* general enough such that they are unavoidable regardless of implementation
* design.
*
*/
#include <stdio.h>
#include "global.h"
/* initialize buffer, call once before first putbits or alignbits */
void
simpeg_encode_initbits(simpeg_encode_context * context)
{
context->outcnt = 8;
context->bytecnt = 0;
}
/* write rightmost n (0<=n<=32) bits of val to outfile */
void
simpeg_encode_putbits(simpeg_encode_context * context,
int val, int n)
{
int i;
unsigned int mask;
mask = 1 << (n-1); /* selects first (leftmost) bit */
for (i=0; i<n; i++)
{
context->outbfr <<= 1;
if (val & mask)
context->outbfr|= 1;
mask >>= 1; /* select next bit */
context->outcnt--;
if (context->outcnt==0) /* 8 bit buffer full */
{
putc(context->outbfr, context->outfile);
context->outcnt = 8;
context->bytecnt++;
}
}
}
/* zero bit stuffing to next byte boundary (5.2.3, 6.2.1) */
void
simpeg_encode_alignbits(simpeg_encode_context * context)
{
if (context->outcnt!=8)
simpeg_encode_putbits(context, 0, context->outcnt);
}
/* return total number of generated bits */
int
simpeg_encode_bitcount(simpeg_encode_context * context)
{
return 8*context->bytecnt + (8-context->outcnt);
}
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