Mercurial > hg > audiostuff
comparison spandsp-0.0.6pre17/src/bitstream.c @ 4:26cd8f1ef0b1
import spandsp-0.0.6pre17
| author | Peter Meerwald <pmeerw@cosy.sbg.ac.at> |
|---|---|
| date | Fri, 25 Jun 2010 15:50:58 +0200 |
| parents | |
| children |
comparison
equal
deleted
inserted
replaced
| 3:c6c5a16ce2f2 | 4:26cd8f1ef0b1 |
|---|---|
| 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 Lesser General Public License version 2.1, | |
| 14 * as 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 Lesser General Public License for more details. | |
| 20 * | |
| 21 * You should have received a copy of the GNU Lesser General Public | |
| 22 * License 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 1.18.4.1 2009/12/28 12:20:46 steveu Exp $ | |
| 26 */ | |
| 27 | |
| 28 /*! \file */ | |
| 29 | |
| 30 #if defined(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/bitstream.h" | |
| 41 | |
| 42 #include "spandsp/private/bitstream.h" | |
| 43 | |
| 44 SPAN_DECLARE(void) bitstream_put(bitstream_state_t *s, uint8_t **c, uint32_t value, int bits) | |
| 45 { | |
| 46 value &= ((1 << bits) - 1); | |
| 47 if (s->lsb_first) | |
| 48 { | |
| 49 if (s->residue + bits <= 32) | |
| 50 { | |
| 51 s->bitstream |= (value << s->residue); | |
| 52 s->residue += bits; | |
| 53 } | |
| 54 while (s->residue >= 8) | |
| 55 { | |
| 56 s->residue -= 8; | |
| 57 *(*c)++ = (uint8_t) (s->bitstream & 0xFF); | |
| 58 s->bitstream >>= 8; | |
| 59 } | |
| 60 } | |
| 61 else | |
| 62 { | |
| 63 if (s->residue + bits <= 32) | |
| 64 { | |
| 65 s->bitstream = (s->bitstream << bits) | value; | |
| 66 s->residue += bits; | |
| 67 } | |
| 68 while (s->residue >= 8) | |
| 69 { | |
| 70 s->residue -= 8; | |
| 71 *(*c)++ = (uint8_t) ((s->bitstream >> s->residue) & 0xFF); | |
| 72 } | |
| 73 } | |
| 74 } | |
| 75 /*- End of function --------------------------------------------------------*/ | |
| 76 | |
| 77 SPAN_DECLARE(void) bitstream_flush(bitstream_state_t *s, uint8_t **c) | |
| 78 { | |
| 79 if (s->residue > 0) | |
| 80 { | |
| 81 s->bitstream &= ((1 << s->residue) - 1); | |
| 82 if (s->lsb_first) | |
| 83 *(*c)++ = (uint8_t) s->bitstream; | |
| 84 else | |
| 85 *(*c)++ = (uint8_t) (s->bitstream << (8 - s->residue)); | |
| 86 s->residue = 0; | |
| 87 } | |
| 88 s->bitstream = 0; | |
| 89 } | |
| 90 /*- End of function --------------------------------------------------------*/ | |
| 91 | |
| 92 SPAN_DECLARE(uint32_t) bitstream_get(bitstream_state_t *s, const uint8_t **c, int bits) | |
| 93 { | |
| 94 uint32_t x; | |
| 95 | |
| 96 if (s->lsb_first) | |
| 97 { | |
| 98 while (s->residue < bits) | |
| 99 { | |
| 100 s->bitstream |= (((uint32_t) *(*c)++) << s->residue); | |
| 101 s->residue += 8; | |
| 102 } | |
| 103 s->residue -= bits; | |
| 104 x = s->bitstream & ((1 << bits) - 1); | |
| 105 s->bitstream >>= bits; | |
| 106 } | |
| 107 else | |
| 108 { | |
| 109 while (s->residue < bits) | |
| 110 { | |
| 111 s->bitstream = (s->bitstream << 8) | ((uint32_t) *(*c)++); | |
| 112 s->residue += 8; | |
| 113 } | |
| 114 s->residue -= bits; | |
| 115 x = (s->bitstream >> s->residue) & ((1 << bits) - 1); | |
| 116 } | |
| 117 return x; | |
| 118 } | |
| 119 /*- End of function --------------------------------------------------------*/ | |
| 120 | |
| 121 SPAN_DECLARE(bitstream_state_t *) bitstream_init(bitstream_state_t *s, int lsb_first) | |
| 122 { | |
| 123 if (s == NULL) | |
| 124 { | |
| 125 if ((s = (bitstream_state_t *) malloc(sizeof(*s))) == NULL) | |
| 126 return NULL; | |
| 127 } | |
| 128 s->bitstream = 0; | |
| 129 s->residue = 0; | |
| 130 s->lsb_first = lsb_first; | |
| 131 return s; | |
| 132 } | |
| 133 /*- End of function --------------------------------------------------------*/ | |
| 134 | |
| 135 SPAN_DECLARE(int) bitstream_release(bitstream_state_t *s) | |
| 136 { | |
| 137 return 0; | |
| 138 } | |
| 139 /*- End of function --------------------------------------------------------*/ | |
| 140 | |
| 141 SPAN_DECLARE(int) bitstream_free(bitstream_state_t *s) | |
| 142 { | |
| 143 if (s) | |
| 144 free(s); | |
| 145 return 0; | |
| 146 } | |
| 147 /*- End of function --------------------------------------------------------*/ | |
| 148 /*- End of file ------------------------------------------------------------*/ |