pycrc 0.6

pycrc is a calculation utility that will provide a CRC reference implementation in Python and a source code generator for C.
The used CRC variant can be chosen from a fast but space-consuming implementation to slower but smaller implementations suitable especially for embedded applications.
The following variants of the CRC algorithm are supported:
- bit_by_bit: the basic algorithm which operates individually on every bit of the augmented message (i.e. the input data with width 0-bits attached to the end). This algorithm is the easiest one to understand, because its a direct implementation of the basic polynomial division, but it is also the slowest among all possible variants.
- bit_by_bit_fast: a variation of the simple bit_by_bit algorithm, which doesnt need the augmented message. This algorithm might be a good choice for embedded platforms, where code space is a major concern.
- table_driven: the standard table driven algorithm. This algorithm works only on models with multiples of 8 as width. This is the fastest variant, because it operates on bytes as opposed to bits, and uses a look-up table of 256 elements, which might not be feasible for small embedded systems, though. Anyway, the number of elements in the look-up table can be reduced by means of the --table_idx_with command line switch. By using 4 bits (16 elements in the look-up table) a significant speed-up can be measured with respect to the bit-by-bit algorithms.
Main features:
- Generate the checksum of a string
- Generate the C header and source files for a client implementation. The algorithm can be chosen from fast but big implementation to slower but smaller implementations suitable especially for embedded applications.