| 1 | /* crc32.c |
| 2 | Copyright (C) 2009-2020 Free Software Foundation, Inc. |
| 3 | |
| 4 | This file is part of the libiberty library. |
| 5 | |
| 6 | This file is free software; you can redistribute it and/or modify |
| 7 | it under the terms of the GNU General Public License as published by |
| 8 | the Free Software Foundation; either version 2 of the License, or |
| 9 | (at your option) any later version. |
| 10 | |
| 11 | In addition to the permissions in the GNU General Public License, the |
| 12 | Free Software Foundation gives you unlimited permission to link the |
| 13 | compiled version of this file into combinations with other programs, |
| 14 | and to distribute those combinations without any restriction coming |
| 15 | from the use of this file. (The General Public License restrictions |
| 16 | do apply in other respects; for example, they cover modification of |
| 17 | the file, and distribution when not linked into a combined |
| 18 | executable.) |
| 19 | |
| 20 | This program is distributed in the hope that it will be useful, |
| 21 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 22 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 23 | GNU General Public License for more details. |
| 24 | |
| 25 | You should have received a copy of the GNU General Public License |
| 26 | along with this program; if not, write to the Free Software |
| 27 | Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA. |
| 28 | */ |
| 29 | |
| 30 | #ifdef HAVE_CONFIG_H |
| 31 | #include "config.h" |
| 32 | #endif |
| 33 | |
| 34 | #include "libiberty.h" |
| 35 | |
| 36 | /* This table was generated by the following program. |
| 37 | |
| 38 | #include <stdio.h> |
| 39 | |
| 40 | int |
| 41 | main () |
| 42 | { |
| 43 | unsigned int i, j; |
| 44 | unsigned int c; |
| 45 | int table[256]; |
| 46 | |
| 47 | for (i = 0; i < 256; i++) |
| 48 | { |
| 49 | for (c = i << 24, j = 8; j > 0; --j) |
| 50 | c = c & 0x80000000 ? (c << 1) ^ 0x04c11db7 : (c << 1); |
| 51 | table[i] = c; |
| 52 | } |
| 53 | |
| 54 | printf ("static const unsigned int crc32_table[] =\n{\n"); |
| 55 | for (i = 0; i < 256; i += 4) |
| 56 | { |
| 57 | printf (" 0x%08x, 0x%08x, 0x%08x, 0x%08x", |
| 58 | table[i + 0], table[i + 1], table[i + 2], table[i + 3]); |
| 59 | if (i + 4 < 256) |
| 60 | putchar (','); |
| 61 | putchar ('\n'); |
| 62 | } |
| 63 | printf ("};\n"); |
| 64 | return 0; |
| 65 | } |
| 66 | |
| 67 | For more information on CRC, see, e.g., |
| 68 | http://www.ross.net/crc/download/crc_v3.txt. */ |
| 69 | |
| 70 | static const unsigned int crc32_table[] = |
| 71 | { |
| 72 | 0x00000000, 0x04c11db7, 0x09823b6e, 0x0d4326d9, |
| 73 | 0x130476dc, 0x17c56b6b, 0x1a864db2, 0x1e475005, |
| 74 | 0x2608edb8, 0x22c9f00f, 0x2f8ad6d6, 0x2b4bcb61, |
| 75 | 0x350c9b64, 0x31cd86d3, 0x3c8ea00a, 0x384fbdbd, |
| 76 | 0x4c11db70, 0x48d0c6c7, 0x4593e01e, 0x4152fda9, |
| 77 | 0x5f15adac, 0x5bd4b01b, 0x569796c2, 0x52568b75, |
| 78 | 0x6a1936c8, 0x6ed82b7f, 0x639b0da6, 0x675a1011, |
| 79 | 0x791d4014, 0x7ddc5da3, 0x709f7b7a, 0x745e66cd, |
| 80 | 0x9823b6e0, 0x9ce2ab57, 0x91a18d8e, 0x95609039, |
| 81 | 0x8b27c03c, 0x8fe6dd8b, 0x82a5fb52, 0x8664e6e5, |
| 82 | 0xbe2b5b58, 0xbaea46ef, 0xb7a96036, 0xb3687d81, |
| 83 | 0xad2f2d84, 0xa9ee3033, 0xa4ad16ea, 0xa06c0b5d, |
| 84 | 0xd4326d90, 0xd0f37027, 0xddb056fe, 0xd9714b49, |
| 85 | 0xc7361b4c, 0xc3f706fb, 0xceb42022, 0xca753d95, |
| 86 | 0xf23a8028, 0xf6fb9d9f, 0xfbb8bb46, 0xff79a6f1, |
| 87 | 0xe13ef6f4, 0xe5ffeb43, 0xe8bccd9a, 0xec7dd02d, |
| 88 | 0x34867077, 0x30476dc0, 0x3d044b19, 0x39c556ae, |
| 89 | 0x278206ab, 0x23431b1c, 0x2e003dc5, 0x2ac12072, |
| 90 | 0x128e9dcf, 0x164f8078, 0x1b0ca6a1, 0x1fcdbb16, |
| 91 | 0x018aeb13, 0x054bf6a4, 0x0808d07d, 0x0cc9cdca, |
| 92 | 0x7897ab07, 0x7c56b6b0, 0x71159069, 0x75d48dde, |
| 93 | 0x6b93dddb, 0x6f52c06c, 0x6211e6b5, 0x66d0fb02, |
| 94 | 0x5e9f46bf, 0x5a5e5b08, 0x571d7dd1, 0x53dc6066, |
| 95 | 0x4d9b3063, 0x495a2dd4, 0x44190b0d, 0x40d816ba, |
| 96 | 0xaca5c697, 0xa864db20, 0xa527fdf9, 0xa1e6e04e, |
| 97 | 0xbfa1b04b, 0xbb60adfc, 0xb6238b25, 0xb2e29692, |
| 98 | 0x8aad2b2f, 0x8e6c3698, 0x832f1041, 0x87ee0df6, |
| 99 | 0x99a95df3, 0x9d684044, 0x902b669d, 0x94ea7b2a, |
| 100 | 0xe0b41de7, 0xe4750050, 0xe9362689, 0xedf73b3e, |
| 101 | 0xf3b06b3b, 0xf771768c, 0xfa325055, 0xfef34de2, |
| 102 | 0xc6bcf05f, 0xc27dede8, 0xcf3ecb31, 0xcbffd686, |
| 103 | 0xd5b88683, 0xd1799b34, 0xdc3abded, 0xd8fba05a, |
| 104 | 0x690ce0ee, 0x6dcdfd59, 0x608edb80, 0x644fc637, |
| 105 | 0x7a089632, 0x7ec98b85, 0x738aad5c, 0x774bb0eb, |
| 106 | 0x4f040d56, 0x4bc510e1, 0x46863638, 0x42472b8f, |
| 107 | 0x5c007b8a, 0x58c1663d, 0x558240e4, 0x51435d53, |
| 108 | 0x251d3b9e, 0x21dc2629, 0x2c9f00f0, 0x285e1d47, |
| 109 | 0x36194d42, 0x32d850f5, 0x3f9b762c, 0x3b5a6b9b, |
| 110 | 0x0315d626, 0x07d4cb91, 0x0a97ed48, 0x0e56f0ff, |
| 111 | 0x1011a0fa, 0x14d0bd4d, 0x19939b94, 0x1d528623, |
| 112 | 0xf12f560e, 0xf5ee4bb9, 0xf8ad6d60, 0xfc6c70d7, |
| 113 | 0xe22b20d2, 0xe6ea3d65, 0xeba91bbc, 0xef68060b, |
| 114 | 0xd727bbb6, 0xd3e6a601, 0xdea580d8, 0xda649d6f, |
| 115 | 0xc423cd6a, 0xc0e2d0dd, 0xcda1f604, 0xc960ebb3, |
| 116 | 0xbd3e8d7e, 0xb9ff90c9, 0xb4bcb610, 0xb07daba7, |
| 117 | 0xae3afba2, 0xaafbe615, 0xa7b8c0cc, 0xa379dd7b, |
| 118 | 0x9b3660c6, 0x9ff77d71, 0x92b45ba8, 0x9675461f, |
| 119 | 0x8832161a, 0x8cf30bad, 0x81b02d74, 0x857130c3, |
| 120 | 0x5d8a9099, 0x594b8d2e, 0x5408abf7, 0x50c9b640, |
| 121 | 0x4e8ee645, 0x4a4ffbf2, 0x470cdd2b, 0x43cdc09c, |
| 122 | 0x7b827d21, 0x7f436096, 0x7200464f, 0x76c15bf8, |
| 123 | 0x68860bfd, 0x6c47164a, 0x61043093, 0x65c52d24, |
| 124 | 0x119b4be9, 0x155a565e, 0x18197087, 0x1cd86d30, |
| 125 | 0x029f3d35, 0x065e2082, 0x0b1d065b, 0x0fdc1bec, |
| 126 | 0x3793a651, 0x3352bbe6, 0x3e119d3f, 0x3ad08088, |
| 127 | 0x2497d08d, 0x2056cd3a, 0x2d15ebe3, 0x29d4f654, |
| 128 | 0xc5a92679, 0xc1683bce, 0xcc2b1d17, 0xc8ea00a0, |
| 129 | 0xd6ad50a5, 0xd26c4d12, 0xdf2f6bcb, 0xdbee767c, |
| 130 | 0xe3a1cbc1, 0xe760d676, 0xea23f0af, 0xeee2ed18, |
| 131 | 0xf0a5bd1d, 0xf464a0aa, 0xf9278673, 0xfde69bc4, |
| 132 | 0x89b8fd09, 0x8d79e0be, 0x803ac667, 0x84fbdbd0, |
| 133 | 0x9abc8bd5, 0x9e7d9662, 0x933eb0bb, 0x97ffad0c, |
| 134 | 0xafb010b1, 0xab710d06, 0xa6322bdf, 0xa2f33668, |
| 135 | 0xbcb4666d, 0xb8757bda, 0xb5365d03, 0xb1f740b4 |
| 136 | }; |
| 137 | |
| 138 | /* |
| 139 | |
| 140 | @deftypefn Extension {unsigned int} crc32 (const unsigned char *@var{buf}, @ |
| 141 | int @var{len}, unsigned int @var{init}) |
| 142 | |
| 143 | Compute the 32-bit CRC of @var{buf} which has length @var{len}. The |
| 144 | starting value is @var{init}; this may be used to compute the CRC of |
| 145 | data split across multiple buffers by passing the return value of each |
| 146 | call as the @var{init} parameter of the next. |
| 147 | |
| 148 | This is used by the @command{gdb} remote protocol for the @samp{qCRC} |
| 149 | command. In order to get the same results as gdb for a block of data, |
| 150 | you must pass the first CRC parameter as @code{0xffffffff}. |
| 151 | |
| 152 | This CRC can be specified as: |
| 153 | |
| 154 | Width : 32 |
| 155 | Poly : 0x04c11db7 |
| 156 | Init : parameter, typically 0xffffffff |
| 157 | RefIn : false |
| 158 | RefOut : false |
| 159 | XorOut : 0 |
| 160 | |
| 161 | This differs from the "standard" CRC-32 algorithm in that the values |
| 162 | are not reflected, and there is no final XOR value. These differences |
| 163 | make it easy to compose the values of multiple blocks. |
| 164 | |
| 165 | @end deftypefn |
| 166 | |
| 167 | */ |
| 168 | |
| 169 | unsigned int |
| 170 | xcrc32 (const unsigned char *buf, int len, unsigned int init) |
| 171 | { |
| 172 | unsigned int crc = init; |
| 173 | while (len--) |
| 174 | { |
| 175 | crc = (crc << 8) ^ crc32_table[((crc >> 24) ^ *buf) & 255]; |
| 176 | buf++; |
| 177 | } |
| 178 | return crc; |
| 179 | } |