CRC-CCITT
=========

Simple CRC16-CCITT implementation written in C, both algorithmic and tabular
implementations.

Theory
------

CRC16-CCITT is a 16-bit CRC that is in use in the HDLC protocol. The notable
features include a low complexity, and that it will yeild a 0 result when
amended to the data (like most proper CRCs).

Usage
-----

To use this implementation in your program, include one of the implementation
header files:
  #include <crc16-ccitt-algorithm.h>
or:
  #include <crc16-ccitt-table.h>

Use the three functions:
  uint16_t crc;
  crc = crc16_ccitt_init();
  crc = crc16_ccitt_update(data, crc);
  ...
  crc = crc16_ccitt_finalize(crc);

The contents of crc is now the CRC for your data in native endian byte order.
See the example.c for a version where the CRC is amended to the data in big
endian byte order, which make the CRC of the compounded data 0x0000.

If you are using crc16-ccitt-table.h, make sure that you include
crc16-ccitt-table.o in your build. crc16-ccitt-table.c is generated using
crc16-ccitt-generate-table, and is easily built:
  $ make crc16-ccitt-table.c

References
- http://srecord.sourceforge.net/crc16-ccitt.html