This is part of a zip compression utility which I an currently writing to get known to lossless compression algorithms. CRC stands for "Cyclic Redundancy Check" and is essentially a hash function based on polynomial division. CRC32 is a widely used implementation of CRC unsing a pre-defined generating polinomial and is applied e.g. to detect errors in low-level communication protocols.
The given implementation is quite fast and computes the CRC32 of a 40MB file in about 3 seconds on my XP2800+.

The archive below contains the source files and a shell-based win32 executable. For use in your own projects, please refer to the !Readme.txt in the archive.

download crc32 (8KB)