| | 1 | /* -*-c-*- |
| | 2 | * |
| | 3 | * $Id: crc32.h,v 1.7 2004/04/08 01:36:11 mdw Exp $ |
| | 4 | * |
| | 5 | * Calculating cyclic redundancy values (non-cryptographic!) |
| | 6 | * |
| | 7 | * (c) 1998 Straylight/Edgeware |
| | 8 | */ |
| | 9 | |
| | 10 | /*----- Licensing notice --------------------------------------------------* |
| | 11 | * |
| | 12 | * This file is part of the mLib utilities library. |
| | 13 | * |
| | 14 | * mLib is free software; you can redistribute it and/or modify |
| | 15 | * it under the terms of the GNU Library General Public License as |
| | 16 | * published by the Free Software Foundation; either version 2 of the |
| | 17 | * License, or (at your option) any later version. |
| | 18 | * |
| | 19 | * mLib is distributed in the hope that it will be useful, |
| | 20 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| | 21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| | 22 | * GNU Library General Public License for more details. |
| | 23 | * |
| | 24 | * You should have received a copy of the GNU Library General Public |
| | 25 | * License along with mLib; if not, write to the Free |
| | 26 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
| | 27 | * MA 02111-1307, USA. |
| | 28 | */ |
| | 29 | |
| | 30 | #ifndef MLIB_CRC32_H |
| | 31 | #define MLIB_CRC32_H |
| | 32 | |
| | 33 | #ifdef __cplusplus |
| | 34 | extern "C" { |
| | 35 | #endif |
| | 36 | |
| | 37 | /*----- Header files ------------------------------------------------------*/ |
| | 38 | |
| | 39 | #ifndef MLIB_BITS_H |
| | 40 | # include "bits.h" |
| | 41 | #endif |
| | 42 | |
| | 43 | /*----- External values ---------------------------------------------------*/ |
| | 44 | |
| | 45 | extern uint32 crc32_table[256]; |
| | 46 | |
| | 47 | /*----- Macros ------------------------------------------------------------*/ |
| | 48 | |
| | 49 | /* --- @CRC32@ --- * |
| | 50 | * |
| | 51 | * Arguments: @uint32 result@ = where to put the result |
| | 52 | * @uint32 crc@ = carryover from previous call, or zero |
| | 53 | * @void *buf@ = pointer to buffer to check |
| | 54 | * @size_t sz@ = size of the buffer |
| | 55 | * |
| | 56 | * Use: A restartable CRC calculator wrapped up in a macro. |
| | 57 | */ |
| | 58 | |
| | 59 | #define CRC32(result, crc, buf, sz) do { \ |
| | 60 | const octet *_p = (const octet *)(buf); \ |
| | 61 | const octet *_l = _p + (sz); \ |
| | 62 | uint32 _crc = U32(~(crc)); \ |
| | 63 | \ |
| | 64 | while (_p < _l) \ |
| | 65 | _crc = (_crc >> 8) ^ crc32_table[U8(*_p++ ^ _crc)]; \ |
| | 66 | (result) = U32(~_crc); \ |
| | 67 | } while (0) |
| | 68 | |
| | 69 | /*----- Functions provided ------------------------------------------------*/ |
| | 70 | |
| | 71 | /* --- @crc32@ --- * |
| | 72 | * |
| | 73 | * Arguments: @uint32 crc@ = carryover from previous call, or zero |
| | 74 | * @const void *buf@ = pointer to buffer to check |
| | 75 | * @size_t sz@ = size of the buffer |
| | 76 | * |
| | 77 | * Returns: The CRC updated by the new buffer. |
| | 78 | * |
| | 79 | * Use: A restartable CRC calculator. This is just a function |
| | 80 | * wrapper for the macro version. |
| | 81 | */ |
| | 82 | |
| | 83 | extern uint32 crc32(uint32 /*crc*/, const void */*buf*/, size_t /*sz*/); |
| | 84 | |
| | 85 | /*----- That's all, folks -------------------------------------------------*/ |
| | 86 | |
| | 87 | #ifdef __cplusplus |
| | 88 | } |
| | 89 | #endif |
| | 90 | |
| | 91 | #endif |
~mdw / mLib / blame_incremental