mirror of
https://github.com/cookiengineer/audacity
synced 2025-05-04 17:49:45 +02:00
115 lines
2.8 KiB
C
115 lines
2.8 KiB
C
/*
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* TwoLAME: an optimized MPEG Audio Layer Two encoder
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*
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* Copyright (C) 2001-2004 Michael Cheng
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* Copyright (C) 2004-2006 The TwoLAME Project
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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* $Id: bitbuffer.c,v 1.3 2008-02-01 19:44:27 richardash1981 Exp $
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*
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include "twolame.h"
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#include "common.h"
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#include "bitbuffer.h"
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#include "mem.h"
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/*create bit buffer*/
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bit_stream* buffer_init( unsigned char *buffer, int buffer_size )
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{
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bit_stream* bs = (bit_stream *)TWOLAME_MALLOC( sizeof(bit_stream) );
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bs->buf = buffer;
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bs->buf_size = buffer_size;
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bs->buf_byte_idx = 0;
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bs->buf_bit_idx = 8;
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bs->totbit = 0;
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bs->eob = FALSE;
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bs->eobs = FALSE;
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return bs;
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}
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/* Dellocate bit buffer */
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void buffer_deinit( bit_stream **bs )
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{
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if (bs==NULL||*bs==NULL) return;
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TWOLAME_FREE( *bs );
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}
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/*write 1 bit from the bit stream */
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void buffer_put1bit (bit_stream * bs, int bit)
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{
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bs->totbit++;
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bs->buf[bs->buf_byte_idx] |= (bit & 0x1) << (bs->buf_bit_idx - 1);
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bs->buf_bit_idx--;
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if (!bs->buf_bit_idx) {
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bs->buf_bit_idx = 8;
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bs->buf_byte_idx++;
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if (bs->buf_byte_idx >= bs->buf_size) {
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//empty_buffer (bs, minimum);
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fprintf(stdout,"buffer_put1bit: error. bit_stream buffer needs to be bigger\n");
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exit(99);
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}
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bs->buf[bs->buf_byte_idx] = 0;
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}
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}
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/*write N bits into the bit stream */
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void buffer_putbits (bit_stream * bs, unsigned int val, int N)
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{
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static const int putmask[9] = { 0x0, 0x1, 0x3, 0x7, 0xf, 0x1f, 0x3f, 0x7f, 0xff };
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register int j = N;
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register int k, tmp;
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bs->totbit += N;
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while (j > 0) {
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k = MIN (j, bs->buf_bit_idx);
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tmp = val >> (j - k);
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bs->buf[bs->buf_byte_idx] |= (tmp & putmask[k]) << (bs->buf_bit_idx - k);
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bs->buf_bit_idx -= k;
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if (!bs->buf_bit_idx) {
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bs->buf_bit_idx = 8;
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bs->buf_byte_idx++;
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if (bs->buf_byte_idx >= bs->buf_size) {
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//empty_buffer (bs, minimum);
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fprintf(stdout,"buffer_putbits: error. bit_stream buffer needs to be bigger\n");
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exit(99);
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}
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bs->buf[bs->buf_byte_idx] = 0;
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}
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j -= k;
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}
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}
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/*return the current bit stream length (in bits)*/
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unsigned long buffer_sstell (bit_stream * bs)
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{
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return (bs->totbit);
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}
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// vim:ts=4:sw=4:nowrap:
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