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Diff: SDCRC.cpp
- Revision:
- 18:2286a4e7fa31
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- 22:3fa5eaf48e81
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/SDCRC.cpp Thu Aug 27 21:50:40 2015 +0000 @@ -0,0 +1,119 @@ +/* SD/MMC File System Library + * Copyright (c) 2015 Neil Thiessen + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +#include "SDCRC.h" + +namespace SDCRC +{ + +namespace +{ +const char m_Crc7Table[] = { + 0x00, 0x09, 0x12, 0x1B, 0x24, 0x2D, 0x36, 0x3F, + 0x48, 0x41, 0x5A, 0x53, 0x6C, 0x65, 0x7E, 0x77, + 0x19, 0x10, 0x0B, 0x02, 0x3D, 0x34, 0x2F, 0x26, + 0x51, 0x58, 0x43, 0x4A, 0x75, 0x7C, 0x67, 0x6E, + 0x32, 0x3B, 0x20, 0x29, 0x16, 0x1F, 0x04, 0x0D, + 0x7A, 0x73, 0x68, 0x61, 0x5E, 0x57, 0x4C, 0x45, + 0x2B, 0x22, 0x39, 0x30, 0x0F, 0x06, 0x1D, 0x14, + 0x63, 0x6A, 0x71, 0x78, 0x47, 0x4E, 0x55, 0x5C, + 0x64, 0x6D, 0x76, 0x7F, 0x40, 0x49, 0x52, 0x5B, + 0x2C, 0x25, 0x3E, 0x37, 0x08, 0x01, 0x1A, 0x13, + 0x7D, 0x74, 0x6F, 0x66, 0x59, 0x50, 0x4B, 0x42, + 0x35, 0x3C, 0x27, 0x2E, 0x11, 0x18, 0x03, 0x0A, + 0x56, 0x5F, 0x44, 0x4D, 0x72, 0x7B, 0x60, 0x69, + 0x1E, 0x17, 0x0C, 0x05, 0x3A, 0x33, 0x28, 0x21, + 0x4F, 0x46, 0x5D, 0x54, 0x6B, 0x62, 0x79, 0x70, + 0x07, 0x0E, 0x15, 0x1C, 0x23, 0x2A, 0x31, 0x38, + 0x41, 0x48, 0x53, 0x5A, 0x65, 0x6C, 0x77, 0x7E, + 0x09, 0x00, 0x1B, 0x12, 0x2D, 0x24, 0x3F, 0x36, + 0x58, 0x51, 0x4A, 0x43, 0x7C, 0x75, 0x6E, 0x67, + 0x10, 0x19, 0x02, 0x0B, 0x34, 0x3D, 0x26, 0x2F, + 0x73, 0x7A, 0x61, 0x68, 0x57, 0x5E, 0x45, 0x4C, + 0x3B, 0x32, 0x29, 0x20, 0x1F, 0x16, 0x0D, 0x04, + 0x6A, 0x63, 0x78, 0x71, 0x4E, 0x47, 0x5C, 0x55, + 0x22, 0x2B, 0x30, 0x39, 0x06, 0x0F, 0x14, 0x1D, + 0x25, 0x2C, 0x37, 0x3E, 0x01, 0x08, 0x13, 0x1A, + 0x6D, 0x64, 0x7F, 0x76, 0x49, 0x40, 0x5B, 0x52, + 0x3C, 0x35, 0x2E, 0x27, 0x18, 0x11, 0x0A, 0x03, + 0x74, 0x7D, 0x66, 0x6F, 0x50, 0x59, 0x42, 0x4B, + 0x17, 0x1E, 0x05, 0x0C, 0x33, 0x3A, 0x21, 0x28, + 0x5F, 0x56, 0x4D, 0x44, 0x7B, 0x72, 0x69, 0x60, + 0x0E, 0x07, 0x1C, 0x15, 0x2A, 0x23, 0x38, 0x31, + 0x46, 0x4F, 0x54, 0x5D, 0x62, 0x6B, 0x70, 0x79 +}; + +const unsigned short m_Crc16Table[256] = { + 0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50A5, 0x60C6, 0x70E7, + 0x8108, 0x9129, 0xA14A, 0xB16B, 0xC18C, 0xD1AD, 0xE1CE, 0xF1EF, + 0x1231, 0x0210, 0x3273, 0x2252, 0x52B5, 0x4294, 0x72F7, 0x62D6, + 0x9339, 0x8318, 0xB37B, 0xA35A, 0xD3BD, 0xC39C, 0xF3FF, 0xE3DE, + 0x2462, 0x3443, 0x0420, 0x1401, 0x64E6, 0x74C7, 0x44A4, 0x5485, + 0xA56A, 0xB54B, 0x8528, 0x9509, 0xE5EE, 0xF5CF, 0xC5AC, 0xD58D, + 0x3653, 0x2672, 0x1611, 0x0630, 0x76D7, 0x66F6, 0x5695, 0x46B4, + 0xB75B, 0xA77A, 0x9719, 0x8738, 0xF7DF, 0xE7FE, 0xD79D, 0xC7BC, + 0x48C4, 0x58E5, 0x6886, 0x78A7, 0x0840, 0x1861, 0x2802, 0x3823, + 0xC9CC, 0xD9ED, 0xE98E, 0xF9AF, 0x8948, 0x9969, 0xA90A, 0xB92B, + 0x5AF5, 0x4AD4, 0x7AB7, 0x6A96, 0x1A71, 0x0A50, 0x3A33, 0x2A12, + 0xDBFD, 0xCBDC, 0xFBBF, 0xEB9E, 0x9B79, 0x8B58, 0xBB3B, 0xAB1A, + 0x6CA6, 0x7C87, 0x4CE4, 0x5CC5, 0x2C22, 0x3C03, 0x0C60, 0x1C41, + 0xEDAE, 0xFD8F, 0xCDEC, 0xDDCD, 0xAD2A, 0xBD0B, 0x8D68, 0x9D49, + 0x7E97, 0x6EB6, 0x5ED5, 0x4EF4, 0x3E13, 0x2E32, 0x1E51, 0x0E70, + 0xFF9F, 0xEFBE, 0xDFDD, 0xCFFC, 0xBF1B, 0xAF3A, 0x9F59, 0x8F78, + 0x9188, 0x81A9, 0xB1CA, 0xA1EB, 0xD10C, 0xC12D, 0xF14E, 0xE16F, + 0x1080, 0x00A1, 0x30C2, 0x20E3, 0x5004, 0x4025, 0x7046, 0x6067, + 0x83B9, 0x9398, 0xA3FB, 0xB3DA, 0xC33D, 0xD31C, 0xE37F, 0xF35E, + 0x02B1, 0x1290, 0x22F3, 0x32D2, 0x4235, 0x5214, 0x6277, 0x7256, + 0xB5EA, 0xA5CB, 0x95A8, 0x8589, 0xF56E, 0xE54F, 0xD52C, 0xC50D, + 0x34E2, 0x24C3, 0x14A0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405, + 0xA7DB, 0xB7FA, 0x8799, 0x97B8, 0xE75F, 0xF77E, 0xC71D, 0xD73C, + 0x26D3, 0x36F2, 0x0691, 0x16B0, 0x6657, 0x7676, 0x4615, 0x5634, + 0xD94C, 0xC96D, 0xF90E, 0xE92F, 0x99C8, 0x89E9, 0xB98A, 0xA9AB, + 0x5844, 0x4865, 0x7806, 0x6827, 0x18C0, 0x08E1, 0x3882, 0x28A3, + 0xCB7D, 0xDB5C, 0xEB3F, 0xFB1E, 0x8BF9, 0x9BD8, 0xABBB, 0xBB9A, + 0x4A75, 0x5A54, 0x6A37, 0x7A16, 0x0AF1, 0x1AD0, 0x2AB3, 0x3A92, + 0xFD2E, 0xED0F, 0xDD6C, 0xCD4D, 0xBDAA, 0xAD8B, 0x9DE8, 0x8DC9, + 0x7C26, 0x6C07, 0x5C64, 0x4C45, 0x3CA2, 0x2C83, 0x1CE0, 0x0CC1, + 0xEF1F, 0xFF3E, 0xCF5D, 0xDF7C, 0xAF9B, 0xBFBA, 0x8FD9, 0x9FF8, + 0x6E17, 0x7E36, 0x4E55, 0x5E74, 0x2E93, 0x3EB2, 0x0ED1, 0x1EF0 +}; +} + +char crc7(const char* data, int length) +{ + //Calculate the CRC7 checksum for the specified data block + char crc = 0; + for (int i = 0; i < length; i++) { + crc = m_Crc7Table[(crc << 1) ^ data[i]]; + } + + //Return the calculated checksum + return crc; +} + +unsigned short crc16(const char* data, int length) +{ + //Calculate the CRC16 checksum for the specified data block + unsigned short crc = 0; + for (int i = 0; i < length; i++) { + crc = (crc << 8) ^ m_Crc16Table[((crc >> 8) ^ data[i]) & 0x00FF]; + } + + //Return the calculated checksum + return crc; +} + +}