include/linux/crc32.h

0001 /*
0002  * crc32.h
0003  * See linux/lib/crc32.c for license and changes
0004  */
0005 #ifndef _LINUX_CRC32_H
0006 #define _LINUX_CRC32_H
0007
0008 #include <linux/types.h>
0009 #include <linux/bitrev.h>
0010
0011 u32 __pure crc32_le(u32 crc, unsigned char const *p, size_t len);
0012 u32 __pure crc32_be(u32 crc, unsigned char const *p, size_t len);
0013
0014 /**
0015  * crc32_le_combine - Combine two crc32 check values into one. For two
0016  *            sequences of bytes, seq1 and seq2 with lengths len1
0017  *            and len2, crc32_le() check values were calculated
0018  *            for each, crc1 and crc2.
0019  *
0020  * @crc1: crc32 of the first block
0021  * @crc2: crc32 of the second block
0022  * @len2: length of the second block
0023  *
0024  * Return: The crc32_le() check value of seq1 and seq2 concatenated,
0025  *     requiring only crc1, crc2, and len2. Note: If seq_full denotes
0026  *     the concatenated memory area of seq1 with seq2, and crc_full
0027  *     the crc32_le() value of seq_full, then crc_full ==
0028  *     crc32_le_combine(crc1, crc2, len2) when crc_full was seeded
0029  *     with the same initializer as crc1, and crc2 seed was 0. See
0030  *     also crc32_combine_test().
0031  */
0032 u32 __attribute_const__ crc32_le_shift(u32 crc, size_t len);
0033
0034 static inline u32 crc32_le_combine(u32 crc1, u32 crc2, size_t len2)
0035 {
0036     return crc32_le_shift(crc1, len2) ^ crc2;
0037 }
0038
0039 u32 __pure __crc32c_le(u32 crc, unsigned char const *p, size_t len);
0040
0041 /**
0042  * __crc32c_le_combine - Combine two crc32c check values into one. For two
0043  *           sequences of bytes, seq1 and seq2 with lengths len1
0044  *           and len2, __crc32c_le() check values were calculated
0045  *           for each, crc1 and crc2.
0046  *
0047  * @crc1: crc32c of the first block
0048  * @crc2: crc32c of the second block
0049  * @len2: length of the second block
0050  *
0051  * Return: The __crc32c_le() check value of seq1 and seq2 concatenated,
0052  *     requiring only crc1, crc2, and len2. Note: If seq_full denotes
0053  *     the concatenated memory area of seq1 with seq2, and crc_full
0054  *     the __crc32c_le() value of seq_full, then crc_full ==
0055  *     __crc32c_le_combine(crc1, crc2, len2) when crc_full was
0056  *     seeded with the same initializer as crc1, and crc2 seed
0057  *     was 0. See also crc32c_combine_test().
0058  */
0059 u32 __attribute_const__ __crc32c_le_shift(u32 crc, size_t len);
0060
0061 static inline u32 __crc32c_le_combine(u32 crc1, u32 crc2, size_t len2)
0062 {
0063     return __crc32c_le_shift(crc1, len2) ^ crc2;
0064 }
0065
0066 #define crc32(seed, data, length)  crc32_le(seed, (unsigned char const *)(data), length)
0067
0068 /*
0069  * Helpers for hash table generation of ethernet nics:
0070  *
0071  * Ethernet sends the least significant bit of a byte first, thus crc32_le
0072  * is used. The output of crc32_le is bit reversed [most significant bit
0073  * is in bit nr 0], thus it must be reversed before use. Except for
0074  * nics that bit swap the result internally...
0075  */
0076 #define ether_crc(length, data)    bitrev32(crc32_le(~0, data, length))
0077 #define ether_crc_le(length, data) crc32_le(~0, data, length)
0078
0079 #endif /* _LINUX_CRC32_H */