CaryCoders / SDFileSystem

A re-written SDFileSystem library with improved compatibility, CRC support, and card removal/replacement support.

Dependencies:   FATFileSystem

Dependents:   demo_gps_sdcard zeus

Fork of SDFileSystem by Neil Thiessen

CRC16.cpp@17:82aa379e427e, 2015-06-16 (annotated)

Committer:
ftagius
Date:
Tue Jun 16 12:02:43 2015 +0000
Revision:
17:82aa379e427e
Parent:
0:2a6d8a096edc 
updates for use with frdm-kl25z

Who changed what in which revision?

UserRevisionLine numberNew contents of line
neilt6 0:2a6d8a096edc 1 /* SD/MMC File System Library
neilt6 0:2a6d8a096edc 2 * Copyright (c) 2014 Neil Thiessen
neilt6 0:2a6d8a096edc 3 *
neilt6 0:2a6d8a096edc 4 * Licensed under the Apache License, Version 2.0 (the "License");
neilt6 0:2a6d8a096edc 5 * you may not use this file except in compliance with the License.
neilt6 0:2a6d8a096edc 6 * You may obtain a copy of the License at
neilt6 0:2a6d8a096edc 7 *
neilt6 0:2a6d8a096edc 8 * http://www.apache.org/licenses/LICENSE-2.0
neilt6 0:2a6d8a096edc 9 *
neilt6 0:2a6d8a096edc 10 * Unless required by applicable law or agreed to in writing, software
neilt6 0:2a6d8a096edc 11 * distributed under the License is distributed on an "AS IS" BASIS,
neilt6 0:2a6d8a096edc 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
neilt6 0:2a6d8a096edc 13 * See the License for the specific language governing permissions and
neilt6 0:2a6d8a096edc 14 * limitations under the License.
neilt6 0:2a6d8a096edc 15 */
neilt6 0:2a6d8a096edc 16
neilt6 0:2a6d8a096edc 17 #include "CRC16.h"
neilt6 0:2a6d8a096edc 18
neilt6 0:2a6d8a096edc 19 namespace
neilt6 0:2a6d8a096edc 20 {
neilt6 0:2a6d8a096edc 21 const unsigned short m_CRC16Table[256] = {
neilt6 0:2a6d8a096edc 22 0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50A5, 0x60C6, 0x70E7,
neilt6 0:2a6d8a096edc 23 0x8108, 0x9129, 0xA14A, 0xB16B, 0xC18C, 0xD1AD, 0xE1CE, 0xF1EF,
neilt6 0:2a6d8a096edc 24 0x1231, 0x0210, 0x3273, 0x2252, 0x52B5, 0x4294, 0x72F7, 0x62D6,
neilt6 0:2a6d8a096edc 25 0x9339, 0x8318, 0xB37B, 0xA35A, 0xD3BD, 0xC39C, 0xF3FF, 0xE3DE,
neilt6 0:2a6d8a096edc 26 0x2462, 0x3443, 0x0420, 0x1401, 0x64E6, 0x74C7, 0x44A4, 0x5485,
neilt6 0:2a6d8a096edc 27 0xA56A, 0xB54B, 0x8528, 0x9509, 0xE5EE, 0xF5CF, 0xC5AC, 0xD58D,
neilt6 0:2a6d8a096edc 28 0x3653, 0x2672, 0x1611, 0x0630, 0x76D7, 0x66F6, 0x5695, 0x46B4,
neilt6 0:2a6d8a096edc 29 0xB75B, 0xA77A, 0x9719, 0x8738, 0xF7DF, 0xE7FE, 0xD79D, 0xC7BC,
neilt6 0:2a6d8a096edc 30 0x48C4, 0x58E5, 0x6886, 0x78A7, 0x0840, 0x1861, 0x2802, 0x3823,
neilt6 0:2a6d8a096edc 31 0xC9CC, 0xD9ED, 0xE98E, 0xF9AF, 0x8948, 0x9969, 0xA90A, 0xB92B,
neilt6 0:2a6d8a096edc 32 0x5AF5, 0x4AD4, 0x7AB7, 0x6A96, 0x1A71, 0x0A50, 0x3A33, 0x2A12,
neilt6 0:2a6d8a096edc 33 0xDBFD, 0xCBDC, 0xFBBF, 0xEB9E, 0x9B79, 0x8B58, 0xBB3B, 0xAB1A,
neilt6 0:2a6d8a096edc 34 0x6CA6, 0x7C87, 0x4CE4, 0x5CC5, 0x2C22, 0x3C03, 0x0C60, 0x1C41,
neilt6 0:2a6d8a096edc 35 0xEDAE, 0xFD8F, 0xCDEC, 0xDDCD, 0xAD2A, 0xBD0B, 0x8D68, 0x9D49,
neilt6 0:2a6d8a096edc 36 0x7E97, 0x6EB6, 0x5ED5, 0x4EF4, 0x3E13, 0x2E32, 0x1E51, 0x0E70,
neilt6 0:2a6d8a096edc 37 0xFF9F, 0xEFBE, 0xDFDD, 0xCFFC, 0xBF1B, 0xAF3A, 0x9F59, 0x8F78,
neilt6 0:2a6d8a096edc 38 0x9188, 0x81A9, 0xB1CA, 0xA1EB, 0xD10C, 0xC12D, 0xF14E, 0xE16F,
neilt6 0:2a6d8a096edc 39 0x1080, 0x00A1, 0x30C2, 0x20E3, 0x5004, 0x4025, 0x7046, 0x6067,
neilt6 0:2a6d8a096edc 40 0x83B9, 0x9398, 0xA3FB, 0xB3DA, 0xC33D, 0xD31C, 0xE37F, 0xF35E,
neilt6 0:2a6d8a096edc 41 0x02B1, 0x1290, 0x22F3, 0x32D2, 0x4235, 0x5214, 0x6277, 0x7256,
neilt6 0:2a6d8a096edc 42 0xB5EA, 0xA5CB, 0x95A8, 0x8589, 0xF56E, 0xE54F, 0xD52C, 0xC50D,
neilt6 0:2a6d8a096edc 43 0x34E2, 0x24C3, 0x14A0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405,
neilt6 0:2a6d8a096edc 44 0xA7DB, 0xB7FA, 0x8799, 0x97B8, 0xE75F, 0xF77E, 0xC71D, 0xD73C,
neilt6 0:2a6d8a096edc 45 0x26D3, 0x36F2, 0x0691, 0x16B0, 0x6657, 0x7676, 0x4615, 0x5634,
neilt6 0:2a6d8a096edc 46 0xD94C, 0xC96D, 0xF90E, 0xE92F, 0x99C8, 0x89E9, 0xB98A, 0xA9AB,
neilt6 0:2a6d8a096edc 47 0x5844, 0x4865, 0x7806, 0x6827, 0x18C0, 0x08E1, 0x3882, 0x28A3,
neilt6 0:2a6d8a096edc 48 0xCB7D, 0xDB5C, 0xEB3F, 0xFB1E, 0x8BF9, 0x9BD8, 0xABBB, 0xBB9A,
neilt6 0:2a6d8a096edc 49 0x4A75, 0x5A54, 0x6A37, 0x7A16, 0x0AF1, 0x1AD0, 0x2AB3, 0x3A92,
neilt6 0:2a6d8a096edc 50 0xFD2E, 0xED0F, 0xDD6C, 0xCD4D, 0xBDAA, 0xAD8B, 0x9DE8, 0x8DC9,
neilt6 0:2a6d8a096edc 51 0x7C26, 0x6C07, 0x5C64, 0x4C45, 0x3CA2, 0x2C83, 0x1CE0, 0x0CC1,
neilt6 0:2a6d8a096edc 52 0xEF1F, 0xFF3E, 0xCF5D, 0xDF7C, 0xAF9B, 0xBFBA, 0x8FD9, 0x9FF8,
neilt6 0:2a6d8a096edc 53 0x6E17, 0x7E36, 0x4E55, 0x5E74, 0x2E93, 0x3EB2, 0x0ED1, 0x1EF0
neilt6 0:2a6d8a096edc 54 };
neilt6 0:2a6d8a096edc 55 }
neilt6 0:2a6d8a096edc 56
neilt6 0:2a6d8a096edc 57 unsigned short CRC16(const char* data, int length)
neilt6 0:2a6d8a096edc 58 {
neilt6 0:2a6d8a096edc 59 //Calculate the CRC16 checksum for the specified data block
neilt6 0:2a6d8a096edc 60 unsigned short crc = 0;
neilt6 0:2a6d8a096edc 61 for (int i = 0; i < length; i++) {
neilt6 0:2a6d8a096edc 62 crc = (crc << 8) ^ m_CRC16Table[((crc >> 8) ^ data[i]) & 0x00FF];
neilt6 0:2a6d8a096edc 63 }
neilt6 0:2a6d8a096edc 64
neilt6 0:2a6d8a096edc 65 //Return the calculated checksum
neilt6 0:2a6d8a096edc 66 return crc;
neilt6 0:2a6d8a096edc 67 }