#include <search.h>
/* taken from https://github.com/floodyberry/siphash */
#define ROTL64(a,b) (((a)<<(b))|((a)>>(64-b)))
static uint64_t
U8TO64_LE(const unsigned char *p) {
return *(const uint64_t *)p;
}
uint64_t
siphash24(const unsigned char key[16], const unsigned char *m, size_t len) {
uint64_t v0, v1, v2, v3;
uint64_t mi, k0, k1;
uint64_t last7;
size_t i, blocks;
k0 = U8TO64_LE(key + 0);
k1 = U8TO64_LE(key + 8);
v0 = k0 ^ 0x736f6d6570736575ull;
v1 = k1 ^ 0x646f72616e646f6dull;
v2 = k0 ^ 0x6c7967656e657261ull;
v3 = k1 ^ 0x7465646279746573ull;
last7 = (uint64_t)(len & 0xff) << 56;
#define sipcompress() \
v0 += v1; v2 += v3; \
v1 = ROTL64(v1,13); v3 = ROTL64(v3,16); \
v1 ^= v0; v3 ^= v2; \
v0 = ROTL64(v0,32); \
v2 += v1; v0 += v3; \
v1 = ROTL64(v1,17); v3 = ROTL64(v3,21); \
v1 ^= v2; v3 ^= v0; \
v2 = ROTL64(v2,32);
for (i = 0, blocks = (len & ~7); i < blocks; i += 8) {
mi = U8TO64_LE(m + i);
v3 ^= mi;
sipcompress()
sipcompress()
v0 ^= mi;
}
switch (len - blocks) {
case 7: last7 |= (uint64_t)m[i + 6] << 48; /* fall through */
case 6: last7 |= (uint64_t)m[i + 5] << 40; /* fall through */
case 5: last7 |= (uint64_t)m[i + 4] << 32; /* fall through */
case 4: last7 |= (uint64_t)m[i + 3] << 24; /* fall through */
case 3: last7 |= (uint64_t)m[i + 2] << 16; /* fall through */
case 2: last7 |= (uint64_t)m[i + 1] << 8; /* fall through */
case 1: last7 |= (uint64_t)m[i + 0] ; /* fall through */
case 0:
default:;
};
v3 ^= last7;
sipcompress()
sipcompress()
v0 ^= last7;
v2 ^= 0xff;
sipcompress()
sipcompress()
sipcompress()
sipcompress()
return v0 ^ v1 ^ v2 ^ v3;
}
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