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// SPDX-License-Identifier: GPL-2.0
#ifdef __KERNEL__
# include <linux/crush/hash.h>
#else
# include "hash.h"
#endif
/*
* Robert Jenkins' function for mixing 32-bit values
* https://burtleburtle.net/bob/hash/evahash.html
* a, b = random bits, c = input and output
*/
#define crush_hashmix(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)
#define crush_hash_seed 1315423911
static __u32 crush_hash32_rjenkins1(__u32 a)
{
__u32 hash = crush_hash_seed ^ a;
__u32 b = a;
__u32 x = 231232;
__u32 y = 1232;
crush_hashmix(b, x, hash);
crush_hashmix(y, a, hash);
return hash;
}
static __u32 crush_hash32_rjenkins1_2(__u32 a, __u32 b)
{
__u32 hash = crush_hash_seed ^ a ^ b;
__u32 x = 231232;
__u32 y = 1232;
crush_hashmix(a, b, hash);
crush_hashmix(x, a, hash);
crush_hashmix(b, y, hash);
return hash;
}
static __u32 crush_hash32_rjenkins1_3(__u32 a, __u32 b, __u32 c)
{
__u32 hash = crush_hash_seed ^ a ^ b ^ c;
__u32 x = 231232;
__u32 y = 1232;
crush_hashmix(a, b, hash);
crush_hashmix(c, x, hash);
crush_hashmix(y, a, hash);
crush_hashmix(b, x, hash);
crush_hashmix(y, c, hash);
return hash;
}
static __u32 crush_hash32_rjenkins1_4(__u32 a, __u32 b, __u32 c, __u32 d)
{
__u32 hash = crush_hash_seed ^ a ^ b ^ c ^ d;
__u32 x = 231232;
__u32 y = 1232;
crush_hashmix(a, b, hash);
crush_hashmix(c, d, hash);
crush_hashmix(a, x, hash);
crush_hashmix(y, b, hash);
crush_hashmix(c, x, hash);
crush_hashmix(y, d, hash);
return hash;
}
static __u32 crush_hash32_rjenkins1_5(__u32 a, __u32 b, __u32 c, __u32 d,
__u32 e)
{
__u32 hash = crush_hash_seed ^ a ^ b ^ c ^ d ^ e;
__u32 x = 231232;
__u32 y = 1232;
crush_hashmix(a, b, hash);
crush_hashmix(c, d, hash);
crush_hashmix(e, x, hash);
crush_hashmix(y, a, hash);
crush_hashmix(b, x, hash);
crush_hashmix(y, c, hash);
crush_hashmix(d, x, hash);
crush_hashmix(y, e, hash);
return hash;
}
__u32 crush_hash32(int type, __u32 a)
{
switch (type) {
case CRUSH_HASH_RJENKINS1:
return crush_hash32_rjenkins1(a);
default:
return 0;
}
}
__u32 crush_hash32_2(int type, __u32 a, __u32 b)
{
switch (type) {
case CRUSH_HASH_RJENKINS1:
return crush_hash32_rjenkins1_2(a, b);
default:
return 0;
}
}
__u32 crush_hash32_3(int type, __u32 a, __u32 b, __u32 c)
{
switch (type) {
case CRUSH_HASH_RJENKINS1:
return crush_hash32_rjenkins1_3(a, b, c);
default:
return 0;
}
}
__u32 crush_hash32_4(int type, __u32 a, __u32 b, __u32 c, __u32 d)
{
switch (type) {
case CRUSH_HASH_RJENKINS1:
return crush_hash32_rjenkins1_4(a, b, c, d);
default:
return 0;
}
}
__u32 crush_hash32_5(int type, __u32 a, __u32 b, __u32 c, __u32 d, __u32 e)
{
switch (type) {
case CRUSH_HASH_RJENKINS1:
return crush_hash32_rjenkins1_5(a, b, c, d, e);
default:
return 0;
}
}
const char *crush_hash_name(int type)
{
switch (type) {
case CRUSH_HASH_RJENKINS1:
return "rjenkins1";
default:
return "unknown";
}
}
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