diff options
Diffstat (limited to 'fs/ceph/ceph_hash.c')
-rw-r--r-- | fs/ceph/ceph_hash.c | 118 |
1 files changed, 0 insertions, 118 deletions
diff --git a/fs/ceph/ceph_hash.c b/fs/ceph/ceph_hash.c deleted file mode 100644 index bd570015d147..000000000000 --- a/fs/ceph/ceph_hash.c +++ /dev/null @@ -1,118 +0,0 @@ - -#include "types.h" - -/* - * Robert Jenkin's hash function. - * http://burtleburtle.net/bob/hash/evahash.html - * This is in the public domain. - */ -#define mix(a, b, c) \ - do { \ - a = a - b; a = a - c; a = a ^ (c >> 13); \ - b = b - c; b = b - a; b = b ^ (a << 8); \ - c = c - a; c = c - b; c = c ^ (b >> 13); \ - a = a - b; a = a - c; a = a ^ (c >> 12); \ - b = b - c; b = b - a; b = b ^ (a << 16); \ - c = c - a; c = c - b; c = c ^ (b >> 5); \ - a = a - b; a = a - c; a = a ^ (c >> 3); \ - b = b - c; b = b - a; b = b ^ (a << 10); \ - c = c - a; c = c - b; c = c ^ (b >> 15); \ - } while (0) - -unsigned ceph_str_hash_rjenkins(const char *str, unsigned length) -{ - const unsigned char *k = (const unsigned char *)str; - __u32 a, b, c; /* the internal state */ - __u32 len; /* how many key bytes still need mixing */ - - /* Set up the internal state */ - len = length; - a = 0x9e3779b9; /* the golden ratio; an arbitrary value */ - b = a; - c = 0; /* variable initialization of internal state */ - - /* handle most of the key */ - while (len >= 12) { - a = a + (k[0] + ((__u32)k[1] << 8) + ((__u32)k[2] << 16) + - ((__u32)k[3] << 24)); - b = b + (k[4] + ((__u32)k[5] << 8) + ((__u32)k[6] << 16) + - ((__u32)k[7] << 24)); - c = c + (k[8] + ((__u32)k[9] << 8) + ((__u32)k[10] << 16) + - ((__u32)k[11] << 24)); - mix(a, b, c); - k = k + 12; - len = len - 12; - } - - /* handle the last 11 bytes */ - c = c + length; - switch (len) { /* all the case statements fall through */ - case 11: - c = c + ((__u32)k[10] << 24); - case 10: - c = c + ((__u32)k[9] << 16); - case 9: - c = c + ((__u32)k[8] << 8); - /* the first byte of c is reserved for the length */ - case 8: - b = b + ((__u32)k[7] << 24); - case 7: - b = b + ((__u32)k[6] << 16); - case 6: - b = b + ((__u32)k[5] << 8); - case 5: - b = b + k[4]; - case 4: - a = a + ((__u32)k[3] << 24); - case 3: - a = a + ((__u32)k[2] << 16); - case 2: - a = a + ((__u32)k[1] << 8); - case 1: - a = a + k[0]; - /* case 0: nothing left to add */ - } - mix(a, b, c); - - return c; -} - -/* - * linux dcache hash - */ -unsigned ceph_str_hash_linux(const char *str, unsigned length) -{ - unsigned long hash = 0; - unsigned char c; - - while (length--) { - c = *str++; - hash = (hash + (c << 4) + (c >> 4)) * 11; - } - return hash; -} - - -unsigned ceph_str_hash(int type, const char *s, unsigned len) -{ - switch (type) { - case CEPH_STR_HASH_LINUX: - return ceph_str_hash_linux(s, len); - case CEPH_STR_HASH_RJENKINS: - return ceph_str_hash_rjenkins(s, len); - default: - return -1; - } -} - -const char *ceph_str_hash_name(int type) -{ - switch (type) { - case CEPH_STR_HASH_LINUX: - return "linux"; - case CEPH_STR_HASH_RJENKINS: - return "rjenkins"; - default: - return "unknown"; - } -} |