include/linux/crc32.h

   1 /*
   2  * crc32.h
   3  * See linux/lib/crc32.c for license and changes
   4  */
   5 #ifndef _LINUX_CRC32_H
   6 #define _LINUX_CRC32_H
   7
   8 #include <linux/types.h>
   9 #include <linux/bitrev.h>
  10
  11 u32 __pure crc32_le(u32 crc, unsigned char const *p, size_t len);
  12 u32 __pure crc32_be(u32 crc, unsigned char const *p, size_t len);
  13
  14 /**
  15  * crc32_le_combine - Combine two crc32 check values into one. For two
  16  *                    sequences of bytes, seq1 and seq2 with lengths len1
  17  *                    and len2, crc32_le() check values were calculated
  18  *                    for each, crc1 and crc2.
  19  *
  20  * @crc1: crc32 of the first block
  21  * @crc2: crc32 of the second block
  22  * @len2: length of the second block
  23  *
  24  * Return: The crc32_le() check value of seq1 and seq2 concatenated,
  25  *         requiring only crc1, crc2, and len2. Note: If seq_full denotes
  26  *         the concatenated memory area of seq1 with seq2, and crc_full
  27  *         the crc32_le() value of seq_full, then crc_full ==
  28  *         crc32_le_combine(crc1, crc2, len2) when crc_full was seeded
  29  *         with the same initializer as crc1, and crc2 seed was 0. See
  30  *         also crc32_combine_test().
  31  */
  32 u32 __attribute_const__ crc32_le_shift(u32 crc, size_t len);
  33
  34 static inline u32 crc32_le_combine(u32 crc1, u32 crc2, size_t len2)
  35 {
  36         return crc32_le_shift(crc1, len2) ^ crc2;
  37 }
  38
  39 u32 __pure __crc32c_le(u32 crc, unsigned char const *p, size_t len);
  40
  41 /**
  42  * __crc32c_le_combine - Combine two crc32c check values into one. For two
  43  *                       sequences of bytes, seq1 and seq2 with lengths len1
  44  *                       and len2, __crc32c_le() check values were calculated
  45  *                       for each, crc1 and crc2.
  46  *
  47  * @crc1: crc32c of the first block
  48  * @crc2: crc32c of the second block
  49  * @len2: length of the second block
  50  *
  51  * Return: The __crc32c_le() check value of seq1 and seq2 concatenated,
  52  *         requiring only crc1, crc2, and len2. Note: If seq_full denotes
  53  *         the concatenated memory area of seq1 with seq2, and crc_full
  54  *         the __crc32c_le() value of seq_full, then crc_full ==
  55  *         __crc32c_le_combine(crc1, crc2, len2) when crc_full was
  56  *         seeded with the same initializer as crc1, and crc2 seed
  57  *         was 0. See also crc32c_combine_test().
  58  */
  59 u32 __attribute_const__ __crc32c_le_shift(u32 crc, size_t len);
  60
  61 static inline u32 __crc32c_le_combine(u32 crc1, u32 crc2, size_t len2)
  62 {
  63         return __crc32c_le_shift(crc1, len2) ^ crc2;
  64 }
  65
  66 #define crc32(seed, data, length)  crc32_le(seed, (unsigned char const *)(data), length)
  67
  68 /*
  69  * Helpers for hash table generation of ethernet nics:
  70  *
  71  * Ethernet sends the least significant bit of a byte first, thus crc32_le
  72  * is used. The output of crc32_le is bit reversed [most significant bit
  73  * is in bit nr 0], thus it must be reversed before use. Except for
  74  * nics that bit swap the result internally...
  75  */
  76 #define ether_crc(length, data)    bitrev32(crc32_le(~0, data, length))
  77 #define ether_crc_le(length, data) crc32_le(~0, data, length)
  78
  79 #endif /* _LINUX_CRC32_H */