diff options
Diffstat (limited to 'lib/crc32.c')
| -rw-r--r-- | lib/crc32.c | 55 |
1 files changed, 29 insertions, 26 deletions
diff --git a/lib/crc32.c b/lib/crc32.c index 02e3b31..4855995 100644 --- a/lib/crc32.c +++ b/lib/crc32.c @@ -25,16 +25,19 @@ #include <linux/module.h> #include <linux/compiler.h> #include <linux/types.h> -#include <linux/slab.h> #include <linux/init.h> #include <asm/atomic.h> #include "crc32defs.h" #if CRC_LE_BITS == 8 -#define tole(x) __constant_cpu_to_le32(x) -#define tobe(x) __constant_cpu_to_be32(x) +# define tole(x) __constant_cpu_to_le32(x) #else -#define tole(x) (x) -#define tobe(x) (x) +# define tole(x) (x) +#endif + +#if CRC_BE_BITS == 8 +# define tobe(x) __constant_cpu_to_be32(x) +#else +# define tobe(x) (x) #endif #include "crc32table.h" @@ -45,33 +48,37 @@ MODULE_LICENSE("GPL"); #if CRC_LE_BITS == 8 || CRC_BE_BITS == 8 static inline u32 -crc32_body(u32 crc, unsigned char const *buf, size_t len, const u32 *tab) +crc32_body(u32 crc, unsigned char const *buf, size_t len, const u32 (*tab)[256]) { # ifdef __LITTLE_ENDIAN -# define DO_CRC(x) crc = tab[(crc ^ (x)) & 255 ] ^ (crc >> 8) +# define DO_CRC(x) crc = tab[0][(crc ^ (x)) & 255] ^ (crc >> 8) +# define DO_CRC4 crc = tab[3][(crc) & 255] ^ \ + tab[2][(crc >> 8) & 255] ^ \ + tab[1][(crc >> 16) & 255] ^ \ + tab[0][(crc >> 24) & 255] # else -# define DO_CRC(x) crc = tab[((crc >> 24) ^ (x)) & 255] ^ (crc << 8) +# define DO_CRC(x) crc = tab[0][((crc >> 24) ^ (x)) & 255] ^ (crc << 8) +# define DO_CRC4 crc = tab[0][(crc) & 255] ^ \ + tab[1][(crc >> 8) & 255] ^ \ + tab[2][(crc >> 16) & 255] ^ \ + tab[3][(crc >> 24) & 255] # endif - const u32 *b = (const u32 *)buf; + const u32 *b; size_t rem_len; /* Align it */ - if (unlikely((long)b & 3 && len)) { - u8 *p = (u8 *)b; + if (unlikely((long)buf & 3 && len)) { do { - DO_CRC(*p++); - } while ((--len) && ((long)p)&3); - b = (u32 *)p; + DO_CRC(*buf++); + } while ((--len) && ((long)buf)&3); } rem_len = len & 3; /* load data 32 bits wide, xor data 32 bits wide. */ len = len >> 2; + b = (const u32 *)buf; for (--b; len; --len) { crc ^= *++b; /* use pre increment for speed */ - DO_CRC(0); - DO_CRC(0); - DO_CRC(0); - DO_CRC(0); + DO_CRC4; } len = rem_len; /* And the last few bytes */ @@ -82,6 +89,8 @@ crc32_body(u32 crc, unsigned char const *buf, size_t len, const u32 *tab) } while (--len); } return crc; +#undef DO_CRC +#undef DO_CRC4 } #endif /** @@ -114,14 +123,11 @@ u32 __pure crc32_le(u32 crc, unsigned char const *p, size_t len) u32 __pure crc32_le(u32 crc, unsigned char const *p, size_t len) { # if CRC_LE_BITS == 8 - const u32 *tab = crc32table_le; + const u32 (*tab)[] = crc32table_le; crc = __cpu_to_le32(crc); crc = crc32_body(crc, p, len, tab); return __le32_to_cpu(crc); -#undef ENDIAN_SHIFT -#undef DO_CRC - # elif CRC_LE_BITS == 4 while (len--) { crc ^= *p++; @@ -174,14 +180,11 @@ u32 __pure crc32_be(u32 crc, unsigned char const *p, size_t len) u32 __pure crc32_be(u32 crc, unsigned char const *p, size_t len) { # if CRC_BE_BITS == 8 - const u32 *tab = crc32table_be; + const u32 (*tab)[] = crc32table_be; crc = __cpu_to_be32(crc); crc = crc32_body(crc, p, len, tab); return __be32_to_cpu(crc); -#undef ENDIAN_SHIFT -#undef DO_CRC - # elif CRC_BE_BITS == 4 while (len--) { crc ^= *p++ << 24; |
