crc16.h

00001 #ifndef CRC16_H_
00002 #define CRC16_H_
00003 
00004 /* General Layout Design taken from Erik van Wijk's crc8 library found at
00005 http://mbed.org/users/evwijk/code/crc8/
00006 */
00007  
00008 /* Takes in a character array with a given number of bytes. Returns the
00009 16 bit CRC tag as a 32 bit integer. numberOfBytes exceeds 16, function returns 0.
00010 */ 
00011 
00012 int     crc16 (char* dataIn, int numberOfBytes);
00013 
00014 /* Takes in a character array with at least (numberOfBytes + 2) entries. A 16-bit
00015 CRC tag is created from the first numberOfBytes elements of dataIn. The 16-bit tag is then
00016 broken into two 8 bit tags. The most significant is stored in dataIn at (numberOfBytes+1) 
00017 and the least significant is stored in dataIn at (numberOfBytes+2)
00018 
00019 *******************************************************************************
00020 Note: numberOfBytes indicates the number of data elements to generate the CRC.
00021 dataIn must be at least of length numberOfBytes + 2 for the two bytes of CRC
00022 *******************************************************************************
00023 */
00024 
00025 void    crc16_attach (char* dataIn, int numberOfBytes);
00026 
00027 /* Takes in a character array of length (numberOfBytes + 2). A 16-bit CRC is created from the first
00028 numberOfBytes elements of dataIn. The elements at numberOfBytes + 1 and numberOfBytes + 2 are assumed
00029 to be a CRC tag created in the form described above and are reassembled into a single integer.
00030 
00031 The calculated CRC and the input CRC are compared
00032 
00033 If they match, funtion is true.
00034 If the two CRC tags to not match, function is false.
00035 
00036 *******************************************************************************
00037 Note: numberOfBytes indicates the number of data elements to generate the CRC.
00038 dataIn must be at least of length numberOfBytes + 2 for the two bytes of CRC
00039 *******************************************************************************
00040 */
00041 bool    crc16_match (char* dataIn, int numberOfBytes);
00042 
00043  
00044 #endif