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Diffstat (limited to '')
-rw-r--r-- | lib/ext2fs/crc32c_defs.h | 59 |
1 files changed, 59 insertions, 0 deletions
diff --git a/lib/ext2fs/crc32c_defs.h b/lib/ext2fs/crc32c_defs.h new file mode 100644 index 0000000..3f9a09e --- /dev/null +++ b/lib/ext2fs/crc32c_defs.h @@ -0,0 +1,59 @@ +/* + * There are multiple 16-bit CRC polynomials in common use, but this is + * *the* standard CRC-32 polynomial, first popularized by Ethernet. + * x^32+x^26+x^23+x^22+x^16+x^12+x^11+x^10+x^8+x^7+x^5+x^4+x^2+x^1+x^0 + */ +#define CRCPOLY_LE 0xedb88320 +#define CRCPOLY_BE 0x04c11db7 + +/* + * This is the CRC32c polynomial, as outlined by Castagnoli. + * x^32+x^28+x^27+x^26+x^25+x^23+x^22+x^20+x^19+x^18+x^14+x^13+x^11+x^10+x^9+ + * x^8+x^6+x^0 + */ +#define CRC32C_POLY_LE 0x82F63B78 +#define CRC32C_POLY_BE 0x1EDC6F41 + +/* How many bits at a time to use. Valid values are 1, 2, 4, 8, 32 and 64. */ +/* For less performance-sensitive, use 4 */ +#ifndef CRC_LE_BITS +# define CRC_LE_BITS 64 +#endif +#ifndef CRC_BE_BITS +# define CRC_BE_BITS 64 +#endif + +/* + * Little-endian CRC computation. Used with serial bit streams sent + * lsbit-first. Be sure to use cpu_to_le32() to append the computed CRC. + */ +#if CRC_LE_BITS > 64 || CRC_LE_BITS < 1 || CRC_LE_BITS == 16 || \ + CRC_LE_BITS & CRC_LE_BITS-1 +# error "CRC_LE_BITS must be one of {1, 2, 4, 8, 32, 64}" +#endif + +/* + * Big-endian CRC computation. Used with serial bit streams sent + * msbit-first. Be sure to use cpu_to_be32() to append the computed CRC. + */ +#if CRC_BE_BITS > 64 || CRC_BE_BITS < 1 || CRC_BE_BITS == 16 || \ + CRC_BE_BITS & CRC_BE_BITS-1 +# error "CRC_BE_BITS must be one of {1, 2, 4, 8, 32, 64}" +#endif + + +#define ___constant_swab32(x) \ + ((uint32_t)( \ + (((uint32_t)(x) & (uint32_t)0x000000ffUL) << 24) | \ + (((uint32_t)(x) & (uint32_t)0x0000ff00UL) << 8) | \ + (((uint32_t)(x) & (uint32_t)0x00ff0000UL) >> 8) | \ + (((uint32_t)(x) & (uint32_t)0xff000000UL) >> 24))) + + +#if (__GNUC__ >= 3) +#define likely(x) __builtin_expect(!!(x), 1) +#define unlikely(x) __builtin_expect(!!(x), 0) +#else +#define likely(x) (x) +#define unlikely(x) (x) +#endif |