Mercurial > hg > audiostuff
comparison spandsp-0.0.3/spandsp-0.0.3/src/bitstream.c @ 5:f762bf195c4b
import spandsp-0.0.3
| author | Peter Meerwald <pmeerw@cosy.sbg.ac.at> |
|---|---|
| date | Fri, 25 Jun 2010 16:00:21 +0200 |
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| 4:26cd8f1ef0b1 | 5:f762bf195c4b |
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| 1 /* | |
| 2 * SpanDSP - a series of DSP components for telephony | |
| 3 * | |
| 4 * bitstream.c - Bitstream composition and decomposition routines. | |
| 5 * | |
| 6 * Written by Steve Underwood <steveu@coppice.org> | |
| 7 * | |
| 8 * Copyright (C) 2006 Steve Underwood | |
| 9 * | |
| 10 * All rights reserved. | |
| 11 * | |
| 12 * This program is free software; you can redistribute it and/or modify | |
| 13 * it under the terms of the GNU General Public License version 2, as | |
| 14 * published by the Free Software Foundation. | |
| 15 * | |
| 16 * This program is distributed in the hope that it will be useful, | |
| 17 * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
| 19 * GNU General Public License for more details. | |
| 20 * | |
| 21 * You should have received a copy of the GNU General Public License | |
| 22 * along with this program; if not, write to the Free Software | |
| 23 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. | |
| 24 * | |
| 25 * $Id: bitstream.c,v 1.6 2006/11/30 15:41:47 steveu Exp $ | |
| 26 */ | |
| 27 | |
| 28 /*! \file */ | |
| 29 | |
| 30 #ifdef HAVE_CONFIG_H | |
| 31 #include <config.h> | |
| 32 #endif | |
| 33 | |
| 34 #include <inttypes.h> | |
| 35 #include <stdlib.h> | |
| 36 #include <string.h> | |
| 37 #include <assert.h> | |
| 38 | |
| 39 #include "spandsp/telephony.h" | |
| 40 #include "spandsp/logging.h" | |
| 41 #include "spandsp/bitstream.h" | |
| 42 | |
| 43 void bitstream_put(bitstream_state_t *s, uint8_t **c, unsigned int value, int bits) | |
| 44 { | |
| 45 value &= ((1 << bits) - 1); | |
| 46 if (s->residue + bits <= 32) | |
| 47 { | |
| 48 s->bitstream |= (value << s->residue); | |
| 49 s->residue += bits; | |
| 50 } | |
| 51 while (s->residue >= 8) | |
| 52 { | |
| 53 s->residue -= 8; | |
| 54 *(*c)++ = (uint8_t)(s->bitstream & 0xFF); | |
| 55 s->bitstream >>= 8; | |
| 56 } | |
| 57 } | |
| 58 /*- End of function --------------------------------------------------------*/ | |
| 59 | |
| 60 void bitstream_flush(bitstream_state_t *s, uint8_t **c) | |
| 61 { | |
| 62 if (s->residue > 0) | |
| 63 { | |
| 64 *(*c)++ = (uint8_t)((s->bitstream << (8 - s->residue)) & 0xFF); | |
| 65 s->residue = 0; | |
| 66 } | |
| 67 } | |
| 68 /*- End of function --------------------------------------------------------*/ | |
| 69 | |
| 70 unsigned int bitstream_get(bitstream_state_t *s, const uint8_t **c, int bits) | |
| 71 { | |
| 72 unsigned int x; | |
| 73 | |
| 74 while (s->residue < bits) | |
| 75 { | |
| 76 x = (unsigned int) *(*c)++; | |
| 77 s->bitstream |= (x << s->residue); | |
| 78 s->residue += 8; | |
| 79 } | |
| 80 s->residue -= bits; | |
| 81 x = s->bitstream & ((1 << bits) - 1); | |
| 82 s->bitstream >>= bits; | |
| 83 return x; | |
| 84 } | |
| 85 /*- End of function --------------------------------------------------------*/ | |
| 86 | |
| 87 void bitstream_put2(bitstream_state_t *s, uint8_t **c, unsigned int value, int bits) | |
| 88 { | |
| 89 value &= ((1 << bits) - 1); | |
| 90 if (s->residue + bits <= 32) | |
| 91 { | |
| 92 s->bitstream = (s->bitstream << bits) | value; | |
| 93 s->residue += bits; | |
| 94 } | |
| 95 while (s->residue >= 8) | |
| 96 { | |
| 97 s->residue -= 8; | |
| 98 *(*c)++ = (uint8_t) ((s->bitstream >> s->residue) & 0xFF); | |
| 99 } | |
| 100 } | |
| 101 /*- End of function --------------------------------------------------------*/ | |
| 102 | |
| 103 void bitstream_flush2(bitstream_state_t *s, uint8_t **c) | |
| 104 { | |
| 105 if (s->residue > 0) | |
| 106 { | |
| 107 *(*c)++ = (uint8_t) ((s->bitstream << (8 - s->residue)) & 0xFF); | |
| 108 s->residue = 0; | |
| 109 } | |
| 110 } | |
| 111 /*- End of function --------------------------------------------------------*/ | |
| 112 | |
| 113 unsigned int bitstream_get2(bitstream_state_t *s, const uint8_t **c, int bits) | |
| 114 { | |
| 115 unsigned int x; | |
| 116 | |
| 117 while (s->residue < bits) | |
| 118 { | |
| 119 x = (unsigned int) *(*c)++; | |
| 120 s->bitstream = (s->bitstream << 8) | x; | |
| 121 s->residue += 8; | |
| 122 } | |
| 123 s->residue -= bits; | |
| 124 x = (s->bitstream >> s->residue) & ((1 << bits) - 1); | |
| 125 return x; | |
| 126 } | |
| 127 /*- End of function --------------------------------------------------------*/ | |
| 128 | |
| 129 bitstream_state_t *bitstream_init(bitstream_state_t *s) | |
| 130 { | |
| 131 if (s) | |
| 132 memset(s, 0, sizeof(*s)); | |
| 133 return s; | |
| 134 } | |
| 135 /*- End of function --------------------------------------------------------*/ | |
| 136 /*- End of file ------------------------------------------------------------*/ |