560 lines
15 KiB
C
560 lines
15 KiB
C
/*
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This file only show how many operations a hash is able to handle.
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It don't show the distribution nor collisions.
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gcc -Wall -O3 -o test_hashes test_hashes.c
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./test_hashes |sort -k 3 -r
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*/
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#include <sys/time.h>
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#include <time.h>
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#include <stdlib.h>
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#include <stdbool.h>
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#include <string.h>
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#include <stdio.h>
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//#include <stdint.h>
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static struct timeval timeval_current(void)
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{
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struct timeval tv;
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gettimeofday(&tv, NULL);
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return tv;
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}
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static double timeval_elapsed(struct timeval *tv)
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{
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struct timeval tv2 = timeval_current();
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return (tv2.tv_sec - tv->tv_sec) +
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(tv2.tv_usec - tv->tv_usec)*1.0e-6;
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}
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#define HAPROXY_BACKENDS 4
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unsigned long haproxy_uri_hash(char *uri, int uri_len){
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unsigned long hash = 0;
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int c;
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while (uri_len--) {
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c = *uri++;
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if (c == '?')
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break;
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hash = c + (hash << 6) + (hash << 16) - hash;
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}
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return hash%HAPROXY_BACKENDS; /* I assume 4 active backends */
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} /* end haproxy_hash() */
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/*
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* http://eternallyconfuzzled.com/tuts/algorithms/jsw_tut_hashing.aspx
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*/
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unsigned sax_hash ( void *key, int len )
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{
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unsigned char *p = key;
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unsigned h = 0;
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int i;
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for ( i = 0; i < len; i++ )
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h ^= ( h << 5 ) + ( h >> 2 ) + p[i];
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return h;
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}
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#include <arpa/inet.h>
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/* len 4 for ipv4 and 16 for ipv6 */
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unsigned int haproxy_server_hash(const char *addr, int len){
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unsigned int h, l;
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l = h = 0;
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while ((l + sizeof (int)) <= len) {
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h ^= ntohl(*(unsigned int *)(&addr[l]));
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l += sizeof (int);
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}
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return h %= HAPROXY_BACKENDS;
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}/* end haproxy_server_hash() */
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int hashpjw(const void *key) {
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const char *ptr;
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unsigned int val;
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/*********************************************************************
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* *
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* Hash the key by performing a number of bit operations on it. *
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* *
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*********************************************************************/
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val = 0;
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ptr = key;
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while (*ptr != '\0') {
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int tmp;
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val = (val << 4) + (*ptr);
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if((tmp = (val & 0xf0000000))) {
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val = val ^ (tmp >> 24);
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val = val ^ tmp;
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}
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ptr++;
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}/* end while */
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return val;
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}/* end hashpjw */
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static unsigned long
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hash_djbx33(
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register unsigned char *key,
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register size_t len)
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{
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register unsigned long hash = 5381;
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/* the hash unrolled eight times */
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for (; len >= 8; len -= 8) {
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hash = ((hash << 5) + hash) + *key++;
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hash = ((hash << 5) + hash) + *key++;
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hash = ((hash << 5) + hash) + *key++;
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hash = ((hash << 5) + hash) + *key++;
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hash = ((hash << 5) + hash) + *key++;
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hash = ((hash << 5) + hash) + *key++;
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hash = ((hash << 5) + hash) + *key++;
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hash = ((hash << 5) + hash) + *key++;
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}
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switch (len) {
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case 7: hash = ((hash << 5) + hash) + *key++; /* fallthrough... */
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case 6: hash = ((hash << 5) + hash) + *key++; /* fallthrough... */
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case 5: hash = ((hash << 5) + hash) + *key++; /* fallthrough... */
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case 4: hash = ((hash << 5) + hash) + *key++; /* fallthrough... */
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case 3: hash = ((hash << 5) + hash) + *key++; /* fallthrough... */
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case 2: hash = ((hash << 5) + hash) + *key++; /* fallthrough... */
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case 1: hash = ((hash << 5) + hash) + *key++; break;
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default: /* case 0: */ break;
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}
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return hash;
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}
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typedef unsigned long int ub4; /* unsigned 4-byte quantities */
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typedef unsigned char ub1; /* unsigned 1-byte quantities */
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ub4 bernstein(ub1 *key, ub4 len, ub4 level){
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ub4 hash = level;
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ub4 i;
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for (i=0; i<len; ++i) hash = 33*hash + key[i];
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return hash;
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}
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/*
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* http://www.azillionmonkeys.com/qed/hash.html
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*/
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#undef get16bits
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#if (defined(__GNUC__) && defined(__i386__)) || defined(__WATCOMC__) \
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|| defined(_MSC_VER) || defined (__BORLANDC__) || defined (__TURBOC__)
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#define get16bits(d) (*((const uint16_t *) (d)))
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#endif
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#if !defined (get16bits)
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#define get16bits(d) ((((uint32_t)(((const uint8_t *)(d))[1])) << 8)\
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+(uint32_t)(((const uint8_t *)(d))[0]) )
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#endif
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uint32_t SuperFastHash (const char * data, int len) {
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uint32_t hash = len, tmp;
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int rem;
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if (len <= 0 || data == NULL) return 0;
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rem = len & 3;
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len >>= 2;
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/* Main loop */
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for (;len > 0; len--) {
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hash += get16bits (data);
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tmp = (get16bits (data+2) << 11) ^ hash;
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hash = (hash << 16) ^ tmp;
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data += 2*sizeof (uint16_t);
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hash += hash >> 11;
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}
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/* Handle end cases */
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switch (rem) {
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case 3: hash += get16bits (data);
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hash ^= hash << 16;
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hash ^= data[sizeof (uint16_t)] << 18;
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hash += hash >> 11;
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break;
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case 2: hash += get16bits (data);
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hash ^= hash << 11;
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hash += hash >> 17;
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break;
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case 1: hash += *data;
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hash ^= hash << 10;
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hash += hash >> 1;
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}
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/* Force "avalanching" of final 127 bits */
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hash ^= hash << 3;
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hash += hash >> 5;
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hash ^= hash << 4;
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hash += hash >> 17;
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hash ^= hash << 25;
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hash += hash >> 6;
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return hash;
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}
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/*
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* This variant is about 15% faster.
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*/
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uint32_t SuperFastHash2 (const char * data, int len) {
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uint32_t hash = len, tmp;
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int rem;
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if (len <= 0 || data == NULL) return 0;
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rem = len & 3;
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len >>= 2;
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/* Main loop */
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for (;len > 0; len--) {
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register uint32_t next;
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next = get16bits(data+2);
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hash += get16bits(data);
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tmp = (next << 11) ^ hash;
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hash = (hash << 16) ^ tmp;
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data += 2*sizeof (uint16_t);
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hash += hash >> 11;
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}
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/* Handle end cases */
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switch (rem) {
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case 3: hash += get16bits (data);
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hash ^= hash << 16;
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hash ^= data[sizeof (uint16_t)] << 18;
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hash += hash >> 11;
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break;
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case 2: hash += get16bits (data);
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hash ^= hash << 11;
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hash += hash >> 17;
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break;
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case 1: hash += *data;
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hash ^= hash << 10;
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hash += hash >> 1;
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}
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/* Force "avalanching" of final 127 bits */
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hash ^= hash << 3;
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hash += hash >> 5;
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hash ^= hash << 4;
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hash += hash >> 17;
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hash ^= hash << 25;
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hash += hash >> 6;
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return hash;
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}
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/*
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* 32 bit FNV-0 hash type
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*/
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typedef unsigned long Fnv32_t;
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/*
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* fnv_32a_str - perform a 32 bit Fowler/Noll/Vo FNV-1a hash on a string
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*
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* input:
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* str - string to hash
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* hval - previous hash value or 0 if first call
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*
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* returns:
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* 32 bit hash as a static hash type
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*
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* NOTE: To use the recommended 32 bit FNV-1a hash, use FNV1_32A_INIT as the
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* hval arg on the first call to either fnv_32a_buf() or fnv_32a_str().
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*/
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Fnv32_t
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fnv_32a_str(char *str, Fnv32_t hval)
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{
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unsigned char *s = (unsigned char *)str; /* unsigned string */
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/*
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* FNV-1a hash each octet in the buffer
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*/
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while (*s) {
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/* xor the bottom with the current octet */
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hval ^= (Fnv32_t)*s++;
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/* #define NO_FNV_GCC_OPTIMIZATION */
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/* multiply by the 32 bit FNV magic prime mod 2^32 */
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#if defined(NO_FNV_GCC_OPTIMIZATION)
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/*
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* 32 bit magic FNV-1a prime
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*/
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#define FNV_32_PRIME ((Fnv32_t)0x01000193)
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hval *= FNV_32_PRIME;
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#else
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hval += (hval<<1) + (hval<<4) + (hval<<7) + (hval<<8) + (hval<<24);
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#endif
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}
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/* return our new hash value */
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return hval;
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}
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/*
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* from lookup3.c, by Bob Jenkins, May 2006, Public Domain.
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*/
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#define rot(x,k) (((x)<<(k)) | ((x)>>(32-(k))))
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/*
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-------------------------------------------------------------------------------
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mix -- mix 3 32-bit values reversibly.
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This is reversible, so any information in (a,b,c) before mix() is
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still in (a,b,c) after mix().
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If four pairs of (a,b,c) inputs are run through mix(), or through
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mix() in reverse, there are at least 32 bits of the output that
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are sometimes the same for one pair and different for another pair.
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This was tested for:
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* pairs that differed by one bit, by two bits, in any combination
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of top bits of (a,b,c), or in any combination of bottom bits of
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(a,b,c).
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* "differ" is defined as +, -, ^, or ~^. For + and -, I transformed
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the output delta to a Gray code (a^(a>>1)) so a string of 1's (as
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is commonly produced by subtraction) look like a single 1-bit
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difference.
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* the base values were pseudorandom, all zero but one bit set, or
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all zero plus a counter that starts at zero.
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Some k values for my "a-=c; a^=rot(c,k); c+=b;" arrangement that
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satisfy this are
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4 6 8 16 19 4
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9 15 3 18 27 15
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14 9 3 7 17 3
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Well, "9 15 3 18 27 15" didn't quite get 32 bits diffing
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for "differ" defined as + with a one-bit base and a two-bit delta. I
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used http://burtleburtle.net/bob/hash/avalanche.html to choose
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the operations, constants, and arrangements of the variables.
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This does not achieve avalanche. There are input bits of (a,b,c)
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that fail to affect some output bits of (a,b,c), especially of a. The
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most thoroughly mixed value is c, but it doesn't really even achieve
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avalanche in c.
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This allows some parallelism. Read-after-writes are good at doubling
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the number of bits affected, so the goal of mixing pulls in the opposite
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direction as the goal of parallelism. I did what I could. Rotates
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seem to cost as much as shifts on every machine I could lay my hands
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on, and rotates are much kinder to the top and bottom bits, so I used
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rotates.
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-------------------------------------------------------------------------------
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*/
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#define mix(a,b,c) \
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{ \
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a -= c; a ^= rot(c, 4); c += b; \
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b -= a; b ^= rot(a, 6); a += c; \
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c -= b; c ^= rot(b, 8); b += a; \
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a -= c; a ^= rot(c,16); c += b; \
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b -= a; b ^= rot(a,19); a += c; \
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c -= b; c ^= rot(b, 4); b += a; \
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}
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/*
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-------------------------------------------------------------------------------
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final -- final mixing of 3 32-bit values (a,b,c) into c
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Pairs of (a,b,c) values differing in only a few bits will usually
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produce values of c that look totally different. This was tested for
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* pairs that differed by one bit, by two bits, in any combination
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of top bits of (a,b,c), or in any combination of bottom bits of
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(a,b,c).
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* "differ" is defined as +, -, ^, or ~^. For + and -, I transformed
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the output delta to a Gray code (a^(a>>1)) so a string of 1's (as
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is commonly produced by subtraction) look like a single 1-bit
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difference.
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* the base values were pseudorandom, all zero but one bit set, or
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all zero plus a counter that starts at zero.
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These constants passed:
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14 11 25 16 4 14 24
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12 14 25 16 4 14 24
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and these came close:
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4 8 15 26 3 22 24
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10 8 15 26 3 22 24
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11 8 15 26 3 22 24
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-------------------------------------------------------------------------------
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*/
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#define final(a,b,c) \
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{ \
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c ^= b; c -= rot(b,14); \
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a ^= c; a -= rot(c,11); \
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b ^= a; b -= rot(a,25); \
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c ^= b; c -= rot(b,16); \
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a ^= c; a -= rot(c,4); \
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b ^= a; b -= rot(a,14); \
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c ^= b; c -= rot(b,24); \
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}
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/*
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--------------------------------------------------------------------
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This works on all machines. To be useful, it requires
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-- that the key be an array of uint32_t's, and
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-- that the length be the number of uint32_t's in the key
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The function hashword() is identical to hashlittle() on little-endian
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machines, and identical to hashbig() on big-endian machines,
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except that the length has to be measured in uint32_ts rather than in
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bytes. hashlittle() is more complicated than hashword() only because
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hashlittle() has to dance around fitting the key bytes into registers.
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--------------------------------------------------------------------
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*/
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uint32_t hashword(
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const uint32_t *k, /* the key, an array of uint32_t values */
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size_t length, /* the length of the key, in uint32_ts */
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uint32_t initval) /* the previous hash, or an arbitrary value */
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{
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uint32_t a,b,c;
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/* Set up the internal state */
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a = b = c = 0xdeadbeef + (((uint32_t)length)<<2) + initval;
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/*------------------------------------------------- handle most of the key */
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while (length > 3)
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{
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a += k[0];
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b += k[1];
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c += k[2];
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mix(a,b,c);
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length -= 3;
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k += 3;
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}
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/*------------------------------------------- handle the last 3 uint32_t's */
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switch(length) /* all the case statements fall through */
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{
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case 3 : c+=k[2];
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case 2 : b+=k[1];
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case 1 : a+=k[0];
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final(a,b,c);
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case 0: /* case 0: nothing left to add */
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break;
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}
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/*------------------------------------------------------ report the result */
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return c;
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}
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/* from K&R book site 139 */
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#define HASHSIZE 101
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unsigned kr_hash(char *s){
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unsigned hashval;
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for(hashval = 0; *s != '\0';s++)
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hashval = *s + 31 * hashval;
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return hashval % HASHSIZE;
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} /* end kr_hash() */
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unsigned fnv_hash ( void *key, int len )
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{
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unsigned char *p = key;
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unsigned h = 2166136261;
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int i;
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for ( i = 0; i < len; i++ )
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h = ( h * 16777619 ) ^ p[i];
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return h;
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}
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unsigned oat_hash ( void *key, int len )
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{
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unsigned char *p = key;
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unsigned h = 0;
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int i;
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for ( i = 0; i < len; i++ ) {
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h += p[i];
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h += ( h << 10 );
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h ^= ( h >> 6 );
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}
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h += ( h << 3 );
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h ^= ( h >> 11 );
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h += ( h << 15 );
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return h;
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}
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unsigned wt_hash ( void *key, int len )
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{
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unsigned char *p = key;
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unsigned h = 0x783c965aUL;
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unsigned step = 16;
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for (; len > 0; len--) {
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h ^= *p * 9;
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p++;
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h = (h << step) | (h >> (32-step));
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step ^= h;
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step &= 0x1F;
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}
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return h;
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}
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#define run_test(fct, args) { \
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unsigned long loop, count; \
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volatile unsigned long result; \
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double delta; \
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struct timeval tv; \
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fprintf(stderr, "Starting %s\n", #fct); \
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tv = timeval_current(); \
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count = 0; \
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do { \
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delta = timeval_elapsed(&tv); \
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for (loop = 0; loop < 1000; loop++) { \
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result = fct args; \
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count++; \
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} \
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} while (delta < 1.0); \
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fprintf(stdout, "%-20s : %10.0f run/sec\n", #fct, count/delta); \
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fflush(stdout); \
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}
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int main(){
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char **start;
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int len;
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char *urls[] = {
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"http://www.microsoft.com/shared/core/1/webservice/navigation.asmx/DisplayDownlevelNavHtml",
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NULL
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};
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|
|
start = urls;
|
|
len = strlen(*urls);
|
|
|
|
run_test(wt_hash, (*urls, len));
|
|
run_test(SuperFastHash2, (*urls, len));
|
|
run_test(SuperFastHash, (*urls, len));
|
|
run_test(haproxy_uri_hash, (*urls, len));
|
|
run_test(haproxy_server_hash, (*urls, len));
|
|
run_test(hashpjw, (*urls));
|
|
run_test(hash_djbx33, ((unsigned char *)*urls, len));
|
|
run_test(bernstein, ((unsigned char *)*urls, len, 4));
|
|
run_test(fnv_32a_str, (*urls, 0));
|
|
run_test(hashword, ((const uint32_t *)*urls,strlen(*urls),0));
|
|
run_test(kr_hash, (*urls));
|
|
run_test(sax_hash, (*urls, len));
|
|
run_test(fnv_hash, (*urls, len));
|
|
run_test(oat_hash, (*urls, len));
|
|
|
|
return 0;
|
|
|
|
}/* end main() */
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