LXR linux/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
  11u32 __pure crc32_le(u32 crc, unsigned char const *p, size_t len);
  12u32 __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 */
  32u32 __attribute_const__ crc32_le_shift(u32 crc, size_t len);
  33
  34static inline u32 crc32_le_combine(u32 crc1, u32 crc2, size_t len2)
  35{
  36        return crc32_le_shift(crc1, len2) ^ crc2;
  37}
  38
  39u32 __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 */
  59u32 __attribute_const__ __crc32c_le_shift(u32 crc, size_t len);
  60
  61static 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 */
  80