// ////////////////////////////////////////////////////////// // Crc32.h // Copyright (c) 2011-2019 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 table is automatically fitted to your needs // uint8_t, uint32_t, int32_t #include // size_t #include // 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); /// merge two CRC32 such that result = crc32(dataB, lengthB, crc32(dataA, lengthA)) uint32_t crc32_combine (uint32_t crcA, uint32_t crcB, size_t lengthB); /// 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