MP3 Player without external hardware MP3 Player without external hardware. A software based MP3 player based on a modified version of libmad. Mono output (at the moment) via AnalogOut. Files are read from an USB drive. This is a demo program, it plays only one file at the moment. Documentation is in "main.cpp" and "config.h"
bit.cpp@0:7627c79db971, 2010-11-26 (annotated)
- Committer:
- Gruenfrosch
- Date:
- Fri Nov 26 12:18:30 2010 +0000
- Revision:
- 0:7627c79db971
First Version
Who changed what in which revision?
User | Revision | Line number | New contents of line |
---|---|---|---|
Gruenfrosch | 0:7627c79db971 | 1 | /* |
Gruenfrosch | 0:7627c79db971 | 2 | * libmad - MPEG audio decoder library |
Gruenfrosch | 0:7627c79db971 | 3 | * Copyright (C) 2000-2004 Underbit Technologies, Inc. |
Gruenfrosch | 0:7627c79db971 | 4 | * |
Gruenfrosch | 0:7627c79db971 | 5 | * This program is free software; you can redistribute it and/or modify |
Gruenfrosch | 0:7627c79db971 | 6 | * it under the terms of the GNU General Public License as published by |
Gruenfrosch | 0:7627c79db971 | 7 | * the Free Software Foundation; either version 2 of the License, or |
Gruenfrosch | 0:7627c79db971 | 8 | * (at your option) any later version. |
Gruenfrosch | 0:7627c79db971 | 9 | * |
Gruenfrosch | 0:7627c79db971 | 10 | * This program is distributed in the hope that it will be useful, |
Gruenfrosch | 0:7627c79db971 | 11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
Gruenfrosch | 0:7627c79db971 | 12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
Gruenfrosch | 0:7627c79db971 | 13 | * GNU General Public License for more details. |
Gruenfrosch | 0:7627c79db971 | 14 | * |
Gruenfrosch | 0:7627c79db971 | 15 | * You should have received a copy of the GNU General Public License |
Gruenfrosch | 0:7627c79db971 | 16 | * along with this program; if not, write to the Free Software |
Gruenfrosch | 0:7627c79db971 | 17 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
Gruenfrosch | 0:7627c79db971 | 18 | * |
Gruenfrosch | 0:7627c79db971 | 19 | * $Id: bit.c,v 1.1 2010/11/23 20:12:57 andy Exp $ |
Gruenfrosch | 0:7627c79db971 | 20 | */ |
Gruenfrosch | 0:7627c79db971 | 21 | |
Gruenfrosch | 0:7627c79db971 | 22 | # include "config.h" |
Gruenfrosch | 0:7627c79db971 | 23 | |
Gruenfrosch | 0:7627c79db971 | 24 | # include "global.h" |
Gruenfrosch | 0:7627c79db971 | 25 | |
Gruenfrosch | 0:7627c79db971 | 26 | # ifdef HAVE_LIMITS_H |
Gruenfrosch | 0:7627c79db971 | 27 | # include <limits.h> |
Gruenfrosch | 0:7627c79db971 | 28 | # else |
Gruenfrosch | 0:7627c79db971 | 29 | # define CHAR_BIT 8 |
Gruenfrosch | 0:7627c79db971 | 30 | # endif |
Gruenfrosch | 0:7627c79db971 | 31 | |
Gruenfrosch | 0:7627c79db971 | 32 | # include "bit.h" |
Gruenfrosch | 0:7627c79db971 | 33 | |
Gruenfrosch | 0:7627c79db971 | 34 | /* |
Gruenfrosch | 0:7627c79db971 | 35 | * This is the lookup table for computing the CRC-check word. |
Gruenfrosch | 0:7627c79db971 | 36 | * As described in section 2.4.3.1 and depicted in Figure A.9 |
Gruenfrosch | 0:7627c79db971 | 37 | * of ISO/IEC 11172-3, the generator polynomial is: |
Gruenfrosch | 0:7627c79db971 | 38 | * |
Gruenfrosch | 0:7627c79db971 | 39 | * G(X) = X^16 + X^15 + X^2 + 1 |
Gruenfrosch | 0:7627c79db971 | 40 | */ |
Gruenfrosch | 0:7627c79db971 | 41 | static |
Gruenfrosch | 0:7627c79db971 | 42 | unsigned short const crc_table[256] = { |
Gruenfrosch | 0:7627c79db971 | 43 | 0x0000, 0x8005, 0x800f, 0x000a, 0x801b, 0x001e, 0x0014, 0x8011, |
Gruenfrosch | 0:7627c79db971 | 44 | 0x8033, 0x0036, 0x003c, 0x8039, 0x0028, 0x802d, 0x8027, 0x0022, |
Gruenfrosch | 0:7627c79db971 | 45 | 0x8063, 0x0066, 0x006c, 0x8069, 0x0078, 0x807d, 0x8077, 0x0072, |
Gruenfrosch | 0:7627c79db971 | 46 | 0x0050, 0x8055, 0x805f, 0x005a, 0x804b, 0x004e, 0x0044, 0x8041, |
Gruenfrosch | 0:7627c79db971 | 47 | 0x80c3, 0x00c6, 0x00cc, 0x80c9, 0x00d8, 0x80dd, 0x80d7, 0x00d2, |
Gruenfrosch | 0:7627c79db971 | 48 | 0x00f0, 0x80f5, 0x80ff, 0x00fa, 0x80eb, 0x00ee, 0x00e4, 0x80e1, |
Gruenfrosch | 0:7627c79db971 | 49 | 0x00a0, 0x80a5, 0x80af, 0x00aa, 0x80bb, 0x00be, 0x00b4, 0x80b1, |
Gruenfrosch | 0:7627c79db971 | 50 | 0x8093, 0x0096, 0x009c, 0x8099, 0x0088, 0x808d, 0x8087, 0x0082, |
Gruenfrosch | 0:7627c79db971 | 51 | |
Gruenfrosch | 0:7627c79db971 | 52 | 0x8183, 0x0186, 0x018c, 0x8189, 0x0198, 0x819d, 0x8197, 0x0192, |
Gruenfrosch | 0:7627c79db971 | 53 | 0x01b0, 0x81b5, 0x81bf, 0x01ba, 0x81ab, 0x01ae, 0x01a4, 0x81a1, |
Gruenfrosch | 0:7627c79db971 | 54 | 0x01e0, 0x81e5, 0x81ef, 0x01ea, 0x81fb, 0x01fe, 0x01f4, 0x81f1, |
Gruenfrosch | 0:7627c79db971 | 55 | 0x81d3, 0x01d6, 0x01dc, 0x81d9, 0x01c8, 0x81cd, 0x81c7, 0x01c2, |
Gruenfrosch | 0:7627c79db971 | 56 | 0x0140, 0x8145, 0x814f, 0x014a, 0x815b, 0x015e, 0x0154, 0x8151, |
Gruenfrosch | 0:7627c79db971 | 57 | 0x8173, 0x0176, 0x017c, 0x8179, 0x0168, 0x816d, 0x8167, 0x0162, |
Gruenfrosch | 0:7627c79db971 | 58 | 0x8123, 0x0126, 0x012c, 0x8129, 0x0138, 0x813d, 0x8137, 0x0132, |
Gruenfrosch | 0:7627c79db971 | 59 | 0x0110, 0x8115, 0x811f, 0x011a, 0x810b, 0x010e, 0x0104, 0x8101, |
Gruenfrosch | 0:7627c79db971 | 60 | |
Gruenfrosch | 0:7627c79db971 | 61 | 0x8303, 0x0306, 0x030c, 0x8309, 0x0318, 0x831d, 0x8317, 0x0312, |
Gruenfrosch | 0:7627c79db971 | 62 | 0x0330, 0x8335, 0x833f, 0x033a, 0x832b, 0x032e, 0x0324, 0x8321, |
Gruenfrosch | 0:7627c79db971 | 63 | 0x0360, 0x8365, 0x836f, 0x036a, 0x837b, 0x037e, 0x0374, 0x8371, |
Gruenfrosch | 0:7627c79db971 | 64 | 0x8353, 0x0356, 0x035c, 0x8359, 0x0348, 0x834d, 0x8347, 0x0342, |
Gruenfrosch | 0:7627c79db971 | 65 | 0x03c0, 0x83c5, 0x83cf, 0x03ca, 0x83db, 0x03de, 0x03d4, 0x83d1, |
Gruenfrosch | 0:7627c79db971 | 66 | 0x83f3, 0x03f6, 0x03fc, 0x83f9, 0x03e8, 0x83ed, 0x83e7, 0x03e2, |
Gruenfrosch | 0:7627c79db971 | 67 | 0x83a3, 0x03a6, 0x03ac, 0x83a9, 0x03b8, 0x83bd, 0x83b7, 0x03b2, |
Gruenfrosch | 0:7627c79db971 | 68 | 0x0390, 0x8395, 0x839f, 0x039a, 0x838b, 0x038e, 0x0384, 0x8381, |
Gruenfrosch | 0:7627c79db971 | 69 | |
Gruenfrosch | 0:7627c79db971 | 70 | 0x0280, 0x8285, 0x828f, 0x028a, 0x829b, 0x029e, 0x0294, 0x8291, |
Gruenfrosch | 0:7627c79db971 | 71 | 0x82b3, 0x02b6, 0x02bc, 0x82b9, 0x02a8, 0x82ad, 0x82a7, 0x02a2, |
Gruenfrosch | 0:7627c79db971 | 72 | 0x82e3, 0x02e6, 0x02ec, 0x82e9, 0x02f8, 0x82fd, 0x82f7, 0x02f2, |
Gruenfrosch | 0:7627c79db971 | 73 | 0x02d0, 0x82d5, 0x82df, 0x02da, 0x82cb, 0x02ce, 0x02c4, 0x82c1, |
Gruenfrosch | 0:7627c79db971 | 74 | 0x8243, 0x0246, 0x024c, 0x8249, 0x0258, 0x825d, 0x8257, 0x0252, |
Gruenfrosch | 0:7627c79db971 | 75 | 0x0270, 0x8275, 0x827f, 0x027a, 0x826b, 0x026e, 0x0264, 0x8261, |
Gruenfrosch | 0:7627c79db971 | 76 | 0x0220, 0x8225, 0x822f, 0x022a, 0x823b, 0x023e, 0x0234, 0x8231, |
Gruenfrosch | 0:7627c79db971 | 77 | 0x8213, 0x0216, 0x021c, 0x8219, 0x0208, 0x820d, 0x8207, 0x0202 |
Gruenfrosch | 0:7627c79db971 | 78 | }; |
Gruenfrosch | 0:7627c79db971 | 79 | |
Gruenfrosch | 0:7627c79db971 | 80 | # define CRC_POLY 0x8005 |
Gruenfrosch | 0:7627c79db971 | 81 | |
Gruenfrosch | 0:7627c79db971 | 82 | /* |
Gruenfrosch | 0:7627c79db971 | 83 | * NAME: bit->init() |
Gruenfrosch | 0:7627c79db971 | 84 | * DESCRIPTION: initialize bit pointer struct |
Gruenfrosch | 0:7627c79db971 | 85 | */ |
Gruenfrosch | 0:7627c79db971 | 86 | void mad_bit_init(struct mad_bitptr *bitptr, unsigned char const *byte) |
Gruenfrosch | 0:7627c79db971 | 87 | { |
Gruenfrosch | 0:7627c79db971 | 88 | bitptr->byte = byte; |
Gruenfrosch | 0:7627c79db971 | 89 | bitptr->cache = 0; |
Gruenfrosch | 0:7627c79db971 | 90 | bitptr->left = CHAR_BIT; |
Gruenfrosch | 0:7627c79db971 | 91 | } |
Gruenfrosch | 0:7627c79db971 | 92 | |
Gruenfrosch | 0:7627c79db971 | 93 | /* |
Gruenfrosch | 0:7627c79db971 | 94 | * NAME: bit->length() |
Gruenfrosch | 0:7627c79db971 | 95 | * DESCRIPTION: return number of bits between start and end points |
Gruenfrosch | 0:7627c79db971 | 96 | */ |
Gruenfrosch | 0:7627c79db971 | 97 | unsigned int mad_bit_length(struct mad_bitptr const *begin, |
Gruenfrosch | 0:7627c79db971 | 98 | struct mad_bitptr const *end) |
Gruenfrosch | 0:7627c79db971 | 99 | { |
Gruenfrosch | 0:7627c79db971 | 100 | return begin->left + |
Gruenfrosch | 0:7627c79db971 | 101 | CHAR_BIT * (end->byte - (begin->byte + 1)) + (CHAR_BIT - end->left); |
Gruenfrosch | 0:7627c79db971 | 102 | } |
Gruenfrosch | 0:7627c79db971 | 103 | |
Gruenfrosch | 0:7627c79db971 | 104 | /* |
Gruenfrosch | 0:7627c79db971 | 105 | * NAME: bit->nextbyte() |
Gruenfrosch | 0:7627c79db971 | 106 | * DESCRIPTION: return pointer to next unprocessed byte |
Gruenfrosch | 0:7627c79db971 | 107 | */ |
Gruenfrosch | 0:7627c79db971 | 108 | unsigned char const *mad_bit_nextbyte(struct mad_bitptr const *bitptr) |
Gruenfrosch | 0:7627c79db971 | 109 | { |
Gruenfrosch | 0:7627c79db971 | 110 | return bitptr->left == CHAR_BIT ? bitptr->byte : bitptr->byte + 1; |
Gruenfrosch | 0:7627c79db971 | 111 | } |
Gruenfrosch | 0:7627c79db971 | 112 | |
Gruenfrosch | 0:7627c79db971 | 113 | /* |
Gruenfrosch | 0:7627c79db971 | 114 | * NAME: bit->skip() |
Gruenfrosch | 0:7627c79db971 | 115 | * DESCRIPTION: advance bit pointer |
Gruenfrosch | 0:7627c79db971 | 116 | */ |
Gruenfrosch | 0:7627c79db971 | 117 | void mad_bit_skip(struct mad_bitptr *bitptr, unsigned int len) |
Gruenfrosch | 0:7627c79db971 | 118 | { |
Gruenfrosch | 0:7627c79db971 | 119 | bitptr->byte += len / CHAR_BIT; |
Gruenfrosch | 0:7627c79db971 | 120 | bitptr->left -= len % CHAR_BIT; |
Gruenfrosch | 0:7627c79db971 | 121 | |
Gruenfrosch | 0:7627c79db971 | 122 | if (bitptr->left > CHAR_BIT) { |
Gruenfrosch | 0:7627c79db971 | 123 | bitptr->byte++; |
Gruenfrosch | 0:7627c79db971 | 124 | bitptr->left += CHAR_BIT; |
Gruenfrosch | 0:7627c79db971 | 125 | } |
Gruenfrosch | 0:7627c79db971 | 126 | |
Gruenfrosch | 0:7627c79db971 | 127 | if (bitptr->left < CHAR_BIT) |
Gruenfrosch | 0:7627c79db971 | 128 | bitptr->cache = *bitptr->byte; |
Gruenfrosch | 0:7627c79db971 | 129 | } |
Gruenfrosch | 0:7627c79db971 | 130 | |
Gruenfrosch | 0:7627c79db971 | 131 | /* |
Gruenfrosch | 0:7627c79db971 | 132 | * NAME: bit->read() |
Gruenfrosch | 0:7627c79db971 | 133 | * DESCRIPTION: read an arbitrary number of bits and return their UIMSBF value |
Gruenfrosch | 0:7627c79db971 | 134 | */ |
Gruenfrosch | 0:7627c79db971 | 135 | unsigned long mad_bit_read(struct mad_bitptr *bitptr, unsigned int len) |
Gruenfrosch | 0:7627c79db971 | 136 | { |
Gruenfrosch | 0:7627c79db971 | 137 | register unsigned long value; |
Gruenfrosch | 0:7627c79db971 | 138 | |
Gruenfrosch | 0:7627c79db971 | 139 | if (bitptr->left == CHAR_BIT) |
Gruenfrosch | 0:7627c79db971 | 140 | bitptr->cache = *bitptr->byte; |
Gruenfrosch | 0:7627c79db971 | 141 | |
Gruenfrosch | 0:7627c79db971 | 142 | if (len < bitptr->left) { |
Gruenfrosch | 0:7627c79db971 | 143 | value = (bitptr->cache & ((1 << bitptr->left) - 1)) >> |
Gruenfrosch | 0:7627c79db971 | 144 | (bitptr->left - len); |
Gruenfrosch | 0:7627c79db971 | 145 | bitptr->left -= len; |
Gruenfrosch | 0:7627c79db971 | 146 | |
Gruenfrosch | 0:7627c79db971 | 147 | return value; |
Gruenfrosch | 0:7627c79db971 | 148 | } |
Gruenfrosch | 0:7627c79db971 | 149 | |
Gruenfrosch | 0:7627c79db971 | 150 | /* remaining bits in current byte */ |
Gruenfrosch | 0:7627c79db971 | 151 | |
Gruenfrosch | 0:7627c79db971 | 152 | value = bitptr->cache & ((1 << bitptr->left) - 1); |
Gruenfrosch | 0:7627c79db971 | 153 | len -= bitptr->left; |
Gruenfrosch | 0:7627c79db971 | 154 | |
Gruenfrosch | 0:7627c79db971 | 155 | bitptr->byte++; |
Gruenfrosch | 0:7627c79db971 | 156 | bitptr->left = CHAR_BIT; |
Gruenfrosch | 0:7627c79db971 | 157 | |
Gruenfrosch | 0:7627c79db971 | 158 | /* more bytes */ |
Gruenfrosch | 0:7627c79db971 | 159 | |
Gruenfrosch | 0:7627c79db971 | 160 | while (len >= CHAR_BIT) { |
Gruenfrosch | 0:7627c79db971 | 161 | value = (value << CHAR_BIT) | *bitptr->byte++; |
Gruenfrosch | 0:7627c79db971 | 162 | len -= CHAR_BIT; |
Gruenfrosch | 0:7627c79db971 | 163 | } |
Gruenfrosch | 0:7627c79db971 | 164 | |
Gruenfrosch | 0:7627c79db971 | 165 | if (len > 0) { |
Gruenfrosch | 0:7627c79db971 | 166 | bitptr->cache = *bitptr->byte; |
Gruenfrosch | 0:7627c79db971 | 167 | |
Gruenfrosch | 0:7627c79db971 | 168 | value = (value << len) | (bitptr->cache >> (CHAR_BIT - len)); |
Gruenfrosch | 0:7627c79db971 | 169 | bitptr->left -= len; |
Gruenfrosch | 0:7627c79db971 | 170 | } |
Gruenfrosch | 0:7627c79db971 | 171 | |
Gruenfrosch | 0:7627c79db971 | 172 | return value; |
Gruenfrosch | 0:7627c79db971 | 173 | } |
Gruenfrosch | 0:7627c79db971 | 174 | |
Gruenfrosch | 0:7627c79db971 | 175 | # if 0 |
Gruenfrosch | 0:7627c79db971 | 176 | /* |
Gruenfrosch | 0:7627c79db971 | 177 | * NAME: bit->write() |
Gruenfrosch | 0:7627c79db971 | 178 | * DESCRIPTION: write an arbitrary number of bits |
Gruenfrosch | 0:7627c79db971 | 179 | */ |
Gruenfrosch | 0:7627c79db971 | 180 | void mad_bit_write(struct mad_bitptr *bitptr, unsigned int len, |
Gruenfrosch | 0:7627c79db971 | 181 | unsigned long value) |
Gruenfrosch | 0:7627c79db971 | 182 | { |
Gruenfrosch | 0:7627c79db971 | 183 | unsigned char *ptr; |
Gruenfrosch | 0:7627c79db971 | 184 | |
Gruenfrosch | 0:7627c79db971 | 185 | ptr = (unsigned char *) bitptr->byte; |
Gruenfrosch | 0:7627c79db971 | 186 | |
Gruenfrosch | 0:7627c79db971 | 187 | /* ... */ |
Gruenfrosch | 0:7627c79db971 | 188 | } |
Gruenfrosch | 0:7627c79db971 | 189 | # endif |
Gruenfrosch | 0:7627c79db971 | 190 | |
Gruenfrosch | 0:7627c79db971 | 191 | /* |
Gruenfrosch | 0:7627c79db971 | 192 | * NAME: bit->crc() |
Gruenfrosch | 0:7627c79db971 | 193 | * DESCRIPTION: compute CRC-check word |
Gruenfrosch | 0:7627c79db971 | 194 | */ |
Gruenfrosch | 0:7627c79db971 | 195 | unsigned short mad_bit_crc(struct mad_bitptr bitptr, unsigned int len, |
Gruenfrosch | 0:7627c79db971 | 196 | unsigned short init) |
Gruenfrosch | 0:7627c79db971 | 197 | { |
Gruenfrosch | 0:7627c79db971 | 198 | register unsigned int crc; |
Gruenfrosch | 0:7627c79db971 | 199 | |
Gruenfrosch | 0:7627c79db971 | 200 | for (crc = init; len >= 32; len -= 32) { |
Gruenfrosch | 0:7627c79db971 | 201 | register unsigned long data; |
Gruenfrosch | 0:7627c79db971 | 202 | |
Gruenfrosch | 0:7627c79db971 | 203 | data = mad_bit_read(&bitptr, 32); |
Gruenfrosch | 0:7627c79db971 | 204 | |
Gruenfrosch | 0:7627c79db971 | 205 | crc = (crc << 8) ^ crc_table[((crc >> 8) ^ (data >> 24)) & 0xff]; |
Gruenfrosch | 0:7627c79db971 | 206 | crc = (crc << 8) ^ crc_table[((crc >> 8) ^ (data >> 16)) & 0xff]; |
Gruenfrosch | 0:7627c79db971 | 207 | crc = (crc << 8) ^ crc_table[((crc >> 8) ^ (data >> 8)) & 0xff]; |
Gruenfrosch | 0:7627c79db971 | 208 | crc = (crc << 8) ^ crc_table[((crc >> 8) ^ (data >> 0)) & 0xff]; |
Gruenfrosch | 0:7627c79db971 | 209 | } |
Gruenfrosch | 0:7627c79db971 | 210 | |
Gruenfrosch | 0:7627c79db971 | 211 | switch (len / 8) { |
Gruenfrosch | 0:7627c79db971 | 212 | case 3: crc = (crc << 8) ^ |
Gruenfrosch | 0:7627c79db971 | 213 | crc_table[((crc >> 8) ^ mad_bit_read(&bitptr, 8)) & 0xff]; |
Gruenfrosch | 0:7627c79db971 | 214 | case 2: crc = (crc << 8) ^ |
Gruenfrosch | 0:7627c79db971 | 215 | crc_table[((crc >> 8) ^ mad_bit_read(&bitptr, 8)) & 0xff]; |
Gruenfrosch | 0:7627c79db971 | 216 | case 1: crc = (crc << 8) ^ |
Gruenfrosch | 0:7627c79db971 | 217 | crc_table[((crc >> 8) ^ mad_bit_read(&bitptr, 8)) & 0xff]; |
Gruenfrosch | 0:7627c79db971 | 218 | |
Gruenfrosch | 0:7627c79db971 | 219 | len %= 8; |
Gruenfrosch | 0:7627c79db971 | 220 | |
Gruenfrosch | 0:7627c79db971 | 221 | case 0: break; |
Gruenfrosch | 0:7627c79db971 | 222 | } |
Gruenfrosch | 0:7627c79db971 | 223 | |
Gruenfrosch | 0:7627c79db971 | 224 | while (len--) { |
Gruenfrosch | 0:7627c79db971 | 225 | register unsigned int msb; |
Gruenfrosch | 0:7627c79db971 | 226 | |
Gruenfrosch | 0:7627c79db971 | 227 | msb = mad_bit_read(&bitptr, 1) ^ (crc >> 15); |
Gruenfrosch | 0:7627c79db971 | 228 | |
Gruenfrosch | 0:7627c79db971 | 229 | crc <<= 1; |
Gruenfrosch | 0:7627c79db971 | 230 | if (msb & 1) |
Gruenfrosch | 0:7627c79db971 | 231 | crc ^= CRC_POLY; |
Gruenfrosch | 0:7627c79db971 | 232 | } |
Gruenfrosch | 0:7627c79db971 | 233 | |
Gruenfrosch | 0:7627c79db971 | 234 | return crc & 0xffff; |
Gruenfrosch | 0:7627c79db971 | 235 | } |