Rob Kluin / nRF51822

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Fork of nRF51822 by Nordic Semiconductor

nordic-sdk/components/libraries/crc16/crc16.c@346:14b090482fd2, 2015-06-19 (annotated)

Committer:
rgrover1
Date:
Fri Jun 19 15:55:35 2015 +0100
Revision:
346:14b090482fd2
Parent:
345:dfde56236c36
Child:
361:d2405f5a4853
Synchronized with git rev bb88aaad

Author: Rohit Grover

renamed BLEDevice to BLE

Who changed what in which revision?

UserRevisionLine numberNew contents of line
rgrover1 346:14b090482fd2 1 /*
rgrover1 346:14b090482fd2 2 * Copyright (c) Nordic Semiconductor ASA
rgrover1 346:14b090482fd2 3 * All rights reserved.
rgrover1 346:14b090482fd2 4 *
rgrover1 346:14b090482fd2 5 * Redistribution and use in source and binary forms, with or without modification,
rgrover1 346:14b090482fd2 6 * are permitted provided that the following conditions are met:
rgrover1 346:14b090482fd2 7 *
rgrover1 346:14b090482fd2 8 * 1. Redistributions of source code must retain the above copyright notice, this
rgrover1 346:14b090482fd2 9 * list of conditions and the following disclaimer.
rgrover1 346:14b090482fd2 10 *
rgrover1 346:14b090482fd2 11 * 2. Redistributions in binary form must reproduce the above copyright notice, this
rgrover1 346:14b090482fd2 12 * list of conditions and the following disclaimer in the documentation and/or
rgrover1 346:14b090482fd2 13 * other materials provided with the distribution.
rgrover1 346:14b090482fd2 14 *
rgrover1 346:14b090482fd2 15 * 3. Neither the name of Nordic Semiconductor ASA nor the names of other
rgrover1 346:14b090482fd2 16 * contributors to this software may be used to endorse or promote products
rgrover1 346:14b090482fd2 17 * derived from this software without specific prior written permission.
rgrover1 346:14b090482fd2 18 *
rgrover1 346:14b090482fd2 19 *
rgrover1 346:14b090482fd2 20 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
rgrover1 346:14b090482fd2 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
rgrover1 346:14b090482fd2 22 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
rgrover1 346:14b090482fd2 23 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
rgrover1 346:14b090482fd2 24 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
rgrover1 346:14b090482fd2 25 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
rgrover1 346:14b090482fd2 26 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
rgrover1 346:14b090482fd2 27 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
rgrover1 346:14b090482fd2 28 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
rgrover1 346:14b090482fd2 29 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
rgrover1 346:14b090482fd2 30 *
rgrover1 346:14b090482fd2 31 */
rgrover1 346:14b090482fd2 32
rgrover1 346:14b090482fd2 33 #include "crc16.h"
rgrover1 346:14b090482fd2 34 #include <stdio.h>
rgrover1 346:14b090482fd2 35
rgrover1 346:14b090482fd2 36 uint16_t crc16_compute(const uint8_t * p_data, uint32_t size, const uint16_t * p_crc)
rgrover1 346:14b090482fd2 37 {
rgrover1 346:14b090482fd2 38 uint32_t i;
rgrover1 346:14b090482fd2 39 uint16_t crc = (p_crc == NULL) ? 0xffff : *p_crc;
rgrover1 346:14b090482fd2 40
rgrover1 346:14b090482fd2 41 for (i = 0; i < size; i++)
rgrover1 346:14b090482fd2 42 {
rgrover1 346:14b090482fd2 43 crc = (unsigned char)(crc >> 8) | (crc << 8);
rgrover1 346:14b090482fd2 44 crc ^= p_data[i];
rgrover1 346:14b090482fd2 45 crc ^= (unsigned char)(crc & 0xff) >> 4;
rgrover1 346:14b090482fd2 46 crc ^= (crc << 8) << 4;
rgrover1 346:14b090482fd2 47 crc ^= ((crc & 0xff) << 4) << 1;
rgrover1 346:14b090482fd2 48 }
rgrover1 346:14b090482fd2 49
rgrover1 346:14b090482fd2 50 return crc;
rgrover1 346:14b090482fd2 51 }