/* SPDX-License-Identifier: LGPL-2.1 * * Based on Paul Hsieh's (LGPG 2.1) hash function * From: http://www.azillionmonkeys.com/qed/hash.html */ #define get16bits(d) (*((const __u16 *) (d))) static __always_inline __u32 SuperFastHash (const char *data, int len, __u32 initval) { __u32 hash = initval; __u32 tmp; int rem; if (len <= 0 || data == NULL) return 0; rem = len & 3; len >>= 2; /* Main loop */ #pragma clang loop unroll(full) for (;len > 0; len--) { hash += get16bits (data); tmp = (get16bits (data+2) << 11) ^ hash; hash = (hash << 16) ^ tmp; data += 2*sizeof (__u16); hash += hash >> 11; } /* Handle end cases */ switch (rem) { case 3: hash += get16bits (data); hash ^= hash << 16; hash ^= ((signed char)data[sizeof (__u16)]) << 18; hash += hash >> 11; break; case 2: hash += get16bits (data); hash ^= hash << 11; hash += hash >> 17; break; case 1: hash += (signed char)*data; hash ^= hash << 10; hash += hash >> 1; } /* Force "avalanching" of final 127 bits */ hash ^= hash << 3; hash += hash >> 5; hash ^= hash << 4; hash += hash >> 17; hash ^= hash << 25; hash += hash >> 6; return hash; }