112 lines
3.0 KiB
C
112 lines
3.0 KiB
C
/*
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* g722_1 - a library for the G.722.1 and Annex C codecs
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*
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* bitstream.c
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*
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* Copyright (C) 2006 Steve Underwood
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*
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* This program 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.
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*/
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/*! \file */
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#if defined(HAVE_CONFIG_H)
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#include <config.h>
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#endif
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#include <inttypes.h>
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#include <stdlib.h>
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#include <string.h>
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#include <assert.h>
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#include "g722_1/g722_1.h"
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#include "bitstream.h"
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void g722_1_bitstream_put(g722_1_bitstream_state_t *s, uint8_t **c, uint32_t value, int bits)
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{
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if (bits < 32)
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value &= ((1 << bits) - 1);
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if (bits > 24)
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{
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/* We can't deal with this many bits in one go. Split up the operation */
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bits -= 8;
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s->bitstream = (s->bitstream << bits) | (value >> 8);
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s->residue += bits;
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while (s->residue >= 8)
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{
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s->residue -= 8;
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*(*c)++ = (uint8_t) ((s->bitstream >> s->residue) & 0xFF);
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}
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bits = 8;
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value &= 0xFF;
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}
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s->bitstream = (s->bitstream << bits) | value;
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s->residue += bits;
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while (s->residue >= 8)
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{
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s->residue -= 8;
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*(*c)++ = (uint8_t) ((s->bitstream >> s->residue) & 0xFF);
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}
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}
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/*- End of function --------------------------------------------------------*/
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uint32_t g722_1_bitstream_get(g722_1_bitstream_state_t *s, const uint8_t **c, int bits)
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{
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uint32_t x;
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if (bits > 24)
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{
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/* We can't deal with this many bits in one go. Split up the operation */
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while (s->residue < 24)
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{
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s->bitstream = (s->bitstream << 8) | ((uint32_t) *(*c)++);
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s->residue += 8;
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}
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s->residue -= 24;
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bits -= 24;
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x = ((s->bitstream >> s->residue) & 0xFFFFFF) << bits;
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while (s->residue < bits)
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{
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s->bitstream = (s->bitstream << 8) | ((uint32_t) *(*c)++);
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s->residue += 8;
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}
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s->residue -= bits;
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x |= (s->bitstream >> s->residue) & ((1 << bits) - 1);
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}
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else
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{
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while (s->residue < bits)
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{
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s->bitstream = (s->bitstream << 8) | ((uint32_t) *(*c)++);
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s->residue += 8;
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}
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s->residue -= bits;
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x = (s->bitstream >> s->residue) & ((1 << bits) - 1);
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}
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return x;
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}
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/*- End of function --------------------------------------------------------*/
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void g722_1_bitstream_flush(g722_1_bitstream_state_t *s, uint8_t **c)
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{
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if (s->residue > 0)
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{
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*(*c)++ = (uint8_t) ((s->bitstream << (8 - s->residue)) & 0xFF);
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s->residue = 0;
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}
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}
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/*- End of function --------------------------------------------------------*/
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g722_1_bitstream_state_t *g722_1_bitstream_init(g722_1_bitstream_state_t *s)
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{
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if (s == NULL)
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return NULL;
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s->bitstream = 0;
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s->residue = 0;
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return s;
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}
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/*- End of function --------------------------------------------------------*/
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/*- End of file ------------------------------------------------------------*/
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