CRC basic library
Dependents: D7A_1x_demo_CodeUpgradeProtocol D7A_1x_demo_big_file D7A_1x_demo_sensors_v3 D7A_1x_demo_send_file_data
Diff: fast_crc32.h
- Revision:
- 2:88116ae677af
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/fast_crc32.h Thu Feb 01 11:41:24 2018 +0000 @@ -0,0 +1,66 @@ +// ////////////////////////////////////////////////////////// +// Crc32.h +// Copyright (c) 2011-2016 Stephan Brumme. All rights reserved. +// Slicing-by-16 contributed by Bulat Ziganshin +// Tableless bytewise CRC contributed by Hagai Gold +// see http://create.stephan-brumme.com/disclaimer.html +// + +// if running on an embedded system, you might consider shrinking the +// big Crc32Lookup table by undefining these lines: +#define CRC32_USE_LOOKUP_TABLE_BYTE +//#define CRC32_USE_LOOKUP_TABLE_SLICING_BY_4 +//#define CRC32_USE_LOOKUP_TABLE_SLICING_BY_8 +//#define CRC32_USE_LOOKUP_TABLE_SLICING_BY_16 +// - crc32_bitwise doesn't need it at all +// - crc32_halfbyte has its own small lookup table +// - crc32_1byte_tableless and crc32_1byte_tableless2 don't need it at all +// - crc32_1byte needs only Crc32Lookup[0] +// - crc32_4bytes needs only Crc32Lookup[0..3] +// - crc32_8bytes needs only Crc32Lookup[0..7] +// - crc32_4x8bytes needs only Crc32Lookup[0..7] +// - crc32_16bytes needs all of Crc32Lookup +// using the aforementioned #defines the the table is automatically fitted to your needs + +// uint8_t, uint32_t, int32_t +#include <stdint.h> +// size_t +#include <stddef.h> + +// crc32_fast selects the fastest algorithm depending on flags (CRC32_USE_LOOKUP_...) +/// compute CRC32 using the fastest algorithm for large datasets on modern CPUs +uint32_t crc32_fast(const void* data, size_t length, uint32_t previousCrc32 = 0); + +/// compute CRC32 (bitwise algorithm) +uint32_t crc32_bitwise (const void* data, size_t length, uint32_t previousCrc32 = 0); +/// compute CRC32 (half-byte algoritm) +uint32_t crc32_halfbyte(const void* data, size_t length, uint32_t previousCrc32 = 0); + +#ifdef CRC32_USE_LOOKUP_TABLE_BYTE +/// compute CRC32 (standard algorithm) +uint32_t crc32_1byte (const void* data, size_t length, uint32_t previousCrc32 = 0); +#endif + +/// compute CRC32 (byte algorithm) without lookup tables +uint32_t crc32_1byte_tableless (const void* data, size_t length, uint32_t previousCrc32 = 0); +/// compute CRC32 (byte algorithm) without lookup tables +uint32_t crc32_1byte_tableless2(const void* data, size_t length, uint32_t previousCrc32 = 0); + +#ifdef CRC32_USE_LOOKUP_TABLE_SLICING_BY_4 +/// compute CRC32 (Slicing-by-4 algorithm) +uint32_t crc32_4bytes (const void* data, size_t length, uint32_t previousCrc32 = 0); +#endif + +#ifdef CRC32_USE_LOOKUP_TABLE_SLICING_BY_8 +/// compute CRC32 (Slicing-by-8 algorithm) +uint32_t crc32_8bytes (const void* data, size_t length, uint32_t previousCrc32 = 0); +/// compute CRC32 (Slicing-by-8 algorithm), unroll inner loop 4 times +uint32_t crc32_4x8bytes(const void* data, size_t length, uint32_t previousCrc32 = 0); +#endif + +#ifdef CRC32_USE_LOOKUP_TABLE_SLICING_BY_16 +/// compute CRC32 (Slicing-by-16 algorithm) +uint32_t crc32_16bytes (const void* data, size_t length, uint32_t previousCrc32 = 0); +/// compute CRC32 (Slicing-by-16 algorithm, prefetch upcoming data blocks) +uint32_t crc32_16bytes_prefetch(const void* data, size_t length, uint32_t previousCrc32 = 0, size_t prefetchAhead = 256); +#endif