#ifndef crc_h #define crc_h /* crc.h */ /* crc - Compute CRC for data (CRC on 8 bits). {{{ * * Copyright (C) 2009 Dufour Jérémy * * APBTeam: * Web: http://apbteam.org/ * Email: team AT apbteam DOT org * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. * * }}} */ #ifndef HOST #include #endif #ifdef HOST /** * CRC i-button, 8-bit (Dallas/Maxim) for host. */ uint8_t _crc_ibutton_update (uint8_t crc, uint8_t data) { uint8_t i; crc = crc ^ data; for (i = 0; i < 8; i++) { if (crc & 0x01) crc = (crc >> 1) ^ 0x8C; else crc >>= 1; } return crc; } #endif /** * Compute CRC. * @param data the data on which to compute CRC. * @param length the length of data (in byte). * @return the computed CRC. */ static inline uint8_t crc_compute (uint8_t *data, uint8_t length) { uint8_t i, crc; /* Sanity check. */ if (!data) return 0; /* For each data byte. */ for (i = 0, crc = 0; i < length; i++) { /* Compute CRC. */ crc = _crc_ibutton_update (crc, data[i]); } /* Return computed CRC. */ return crc; } #endif /* crc_h */