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ae5f7dadef
Aleksandar Lazic has collected many hashing algorithms and put them in one file to ease benchmarking. Some algos look promising, some of them have been checked further with uri_hash. Some results on various systems/hardware are stored in hash_results.txt.
378 lines
9.2 KiB
C
378 lines
9.2 KiB
C
#include <stdio.h>
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#include <string.h>
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#include <arpa/inet.h>
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#define NSERV 10
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#define MAXLINE 1000
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char line[MAXLINE];
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int counts_gd1[NSERV][NSERV];
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static unsigned long hash_gd1(char *uri)
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{
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unsigned long hash = 0;
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int c;
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while ((c = *uri++))
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hash = c + (hash << 6) + (hash << 16) - hash;
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return hash;
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}
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int counts_gd2[NSERV][NSERV];
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static unsigned long hash_gd2(char *uri)
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{
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unsigned long hash = 0;
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int c;
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while ((c = *uri++)) {
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if (c == '?' || c == '\n')
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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;
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}
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int counts_gd3[NSERV][NSERV];
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static unsigned long hash_gd3(char *uri)
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{
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unsigned long hash = 0;
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int c;
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while ((c = *uri++)) {
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if (c == '?' || c == '\n')
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break;
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hash = c - (hash << 3) + (hash << 15) - hash;
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}
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return hash;
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}
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int counts_gd4[NSERV][NSERV];
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static unsigned long hash_gd4(char *uri)
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{
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unsigned long hash = 0;
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int c;
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while ((c = *uri++)) {
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if (c == '?' || c == '\n')
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break;
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hash = hash + (hash << 6) - (hash << 15) - c;
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}
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return hash;
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}
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int counts_gd5[NSERV][NSERV];
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static unsigned long hash_gd5(char *uri)
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{
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unsigned long hash = 0;
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int c;
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while ((c = *uri++)) {
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if (c == '?' || c == '\n')
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break;
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hash = hash + (hash << 2) - (hash << 19) - c;
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}
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return hash;
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}
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int counts_gd6[NSERV][NSERV];
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static unsigned long hash_gd6(char *uri)
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{
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unsigned long hash = 0;
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int c;
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while ((c = *uri++)) {
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if (c == '?' || c == '\n')
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break;
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hash = hash + (hash << 2) - (hash << 22) - c;
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}
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return hash;
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}
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int counts_wt1[NSERV][NSERV];
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static unsigned long hash_wt1(int hsize, char *string) {
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int bits;
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unsigned long data, val;
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bits = val = data = 0;
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while (*string) {
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if (*string == '?' || *string == '\n')
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break;
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data |= ((unsigned long)(unsigned char)*string) << bits;
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bits += 8;
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while (bits >= hsize) {
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val ^= data - (val >> hsize);
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bits -= hsize;
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data >>= hsize;
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}
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string++;
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}
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val ^= data;
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while (val > ((1 << hsize) - 1)) {
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val = (val & ((1 << hsize) - 1)) ^ (val >> hsize);
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}
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return val;
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}
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/*
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* efficient hash : no duplicate on the first 65536 values of 2 bytes.
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* less than 0.1% duplicates for the first 1.6 M values of 3 bytes.
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*/
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int counts_wt2[NSERV][NSERV];
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typedef unsigned int u_int32_t;
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static inline u_int32_t shl32(u_int32_t i, int count) {
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if (count == 32)
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return 0;
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return i << count;
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}
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static inline u_int32_t shr32(u_int32_t i, int count) {
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if (count == 32)
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return 0;
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return i >> count;
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}
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static unsigned int rev32(unsigned int c) {
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c = ((c & 0x0000FFFF) << 16)| ((c & 0xFFFF0000) >> 16);
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c = ((c & 0x00FF00FF) << 8) | ((c & 0xFF00FF00) >> 8);
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c = ((c & 0x0F0F0F0F) << 4) | ((c & 0xF0F0F0F0) >> 4);
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c = ((c & 0x33333333) << 2) | ((c & 0xCCCCCCCC) >> 2);
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c = ((c & 0x55555555) << 1) | ((c & 0xAAAAAAAA) >> 1);
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return c;
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}
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int hash_wt2(const char *src, int len) {
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unsigned int i = 0x3C964BA5; /* as many ones as zeroes */
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unsigned int j;
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unsigned int ih, il;
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int bit;
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while (len--) {
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j = (unsigned char)*src++;
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if (j == '?' || j == '\n')
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break;
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bit = rev32(j - i);
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bit = bit - (bit >> 3) + (bit >> 16) - j;
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bit &= 0x1f;
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ih = shr32(i, bit);
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il = i & (shl32(1, bit) - 1);
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i = shl32(il, 32-bit) - ih - ~j;
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}
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return i;
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}
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//typedef unsigned int uint32_t;
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//typedef unsigned short uint8_t;
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//typedef unsigned char uint16_t;
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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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/*
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* This function has a hole of 11 unused bits in bytes 2 and 3 of each block of
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* 32 bits.
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*/
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int counts_SuperFastHash[NSERV][NSERV];
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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 uses all bits from the input block, and is about 15% faster.
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*/
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int counts_SuperFastHash2[NSERV][NSERV];
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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) | (next >> 21)) ^ 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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/* len 4 for ipv4 and 16 for ipv6 */
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int counts_srv[NSERV][NSERV];
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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;
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}/* end haproxy_server_hash() */
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void count_hash_results(unsigned long hash, int counts[NSERV][NSERV]) {
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int srv, nsrv;
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for (nsrv = 0; nsrv < NSERV; nsrv++) {
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srv = hash % (nsrv + 1);
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counts[nsrv][srv]++;
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}
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}
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void dump_hash_results(char *name, int counts[NSERV][NSERV]) {
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int srv, nsrv;
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printf("%s:\n", name);
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for (nsrv = 0; nsrv < NSERV; nsrv++) {
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printf("%02d srv: ", nsrv+1);
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for (srv = 0; srv <= nsrv; srv++) {
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//printf("%6d ", counts[nsrv][srv]);
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//printf("%3.1f ", (100.0*counts[nsrv][srv]) / (double)counts[0][0]);
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printf("%3.1f ", 100.0*(counts[nsrv][srv] - (double)counts[0][0]/(nsrv+1)) / (double)counts[0][0]);
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}
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printf("\n");
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}
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printf("\n");
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}
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int main() {
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memset(counts_gd1, 0, sizeof(counts_gd1));
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memset(counts_gd2, 0, sizeof(counts_gd2));
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memset(counts_gd3, 0, sizeof(counts_gd3));
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memset(counts_gd4, 0, sizeof(counts_gd4));
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memset(counts_gd5, 0, sizeof(counts_gd5));
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memset(counts_gd6, 0, sizeof(counts_gd6));
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memset(counts_wt1, 0, sizeof(counts_wt1));
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memset(counts_wt2, 0, sizeof(counts_wt2));
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memset(counts_srv, 0, sizeof(counts_srv));
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memset(counts_SuperFastHash, 0, sizeof(counts_SuperFastHash));
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memset(counts_SuperFastHash2, 0, sizeof(counts_SuperFastHash2));
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while (fgets(line, MAXLINE, stdin) != NULL) {
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count_hash_results(hash_gd1(line), counts_gd1);
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count_hash_results(hash_gd2(line), counts_gd2);
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count_hash_results(hash_gd3(line), counts_gd3);
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count_hash_results(hash_gd4(line), counts_gd4);
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count_hash_results(hash_gd5(line), counts_gd5);
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count_hash_results(hash_gd6(line), counts_gd6);
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count_hash_results(hash_wt1(31, line), counts_wt1);
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count_hash_results(hash_wt2(line, strlen(line)), counts_wt2);
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count_hash_results(haproxy_server_hash(line, strlen(line)), counts_srv);
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count_hash_results(SuperFastHash(line, strlen(line)), counts_SuperFastHash);
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count_hash_results(SuperFastHash2(line, strlen(line)), counts_SuperFastHash2);
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}
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dump_hash_results("hash_gd1", counts_gd1);
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dump_hash_results("hash_gd2", counts_gd2);
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dump_hash_results("hash_gd3", counts_gd3);
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dump_hash_results("hash_gd4", counts_gd4);
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dump_hash_results("hash_gd5", counts_gd5);
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dump_hash_results("hash_gd6", counts_gd6);
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dump_hash_results("hash_wt1", counts_wt1);
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dump_hash_results("hash_wt2", counts_wt2);
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dump_hash_results("haproxy_server_hash", counts_srv);
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dump_hash_results("SuperFastHash", counts_SuperFastHash);
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dump_hash_results("SuperFastHash2", counts_SuperFastHash2);
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return 0;
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}
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