crc.c

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/*
 * This file is part of the libsigrok project.
 *
 * Copyright (C) 2015 Aurelien Jacobs <aurel@gnuage.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 3 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, see <http://www.gnu.org/licenses/>.
 */

#include <config.h>
#include <stdint.h>
#include <libsigrok/libsigrok.h>
#include "libsigrok-internal.h"

SR_PRIV uint16_t sr_crc16(uint16_t crc, const uint8_t *buffer, int len)
{
        int i;

        if (!buffer || len < 0)
                return crc;

        while (len--) {
                crc ^= *buffer++;
                for (i = 0; i < 8; i++) {
                        int carry = crc & 1;
                        crc >>= 1;
                        if (carry)
                                crc ^= 0xA001;
                }
        }

        return crc;
}