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// SPDX-License-Identifier: GPL-2.0
// Copyright (c) 2019 Facebook
#include <features.h>
typedef unsigned int u32;
static __always_inline u32 rol32(u32 word, unsigned int shift)
{
return (word << shift) | (word >> ((-shift) & 31));
}
#define __jhash_mix(a, b, c) \
{ \
a -= c; a ^= rol32(c, 4); c += b; \
b -= a; b ^= rol32(a, 6); a += c; \
c -= b; c ^= rol32(b, 8); b += a; \
a -= c; a ^= rol32(c, 16); c += b; \
b -= a; b ^= rol32(a, 19); a += c; \
c -= b; c ^= rol32(b, 4); b += a; \
}
#define __jhash_final(a, b, c) \
{ \
c ^= b; c -= rol32(b, 14); \
a ^= c; a -= rol32(c, 11); \
b ^= a; b -= rol32(a, 25); \
c ^= b; c -= rol32(b, 16); \
a ^= c; a -= rol32(c, 4); \
b ^= a; b -= rol32(a, 14); \
c ^= b; c -= rol32(b, 24); \
}
#define JHASH_INITVAL 0xdeadbeef
static ATTR
u32 jhash(const void *key, u32 length, u32 initval)
{
u32 a, b, c;
const unsigned char *k = key;
a = b = c = JHASH_INITVAL + length + initval;
while (length > 12) {
a += *(volatile u32 *)(k);
b += *(volatile u32 *)(k + 4);
c += *(volatile u32 *)(k + 8);
__jhash_mix(a, b, c);
length -= 12;
k += 12;
}
switch (length) {
case 12: c += (u32)k[11]<<24;
case 11: c += (u32)k[10]<<16;
case 10: c += (u32)k[9]<<8;
case 9: c += k[8];
case 8: b += (u32)k[7]<<24;
case 7: b += (u32)k[6]<<16;
case 6: b += (u32)k[5]<<8;
case 5: b += k[4];
case 4: a += (u32)k[3]<<24;
case 3: a += (u32)k[2]<<16;
case 2: a += (u32)k[1]<<8;
case 1: a += k[0];
c ^= a;
__jhash_final(a, b, c);
case 0: /* Nothing left to add */
break;
}
return c;
}
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