This repository has been archived on 2023-08-20. You can view files and clone it, but cannot push or open issues or pull requests.
libcfu/examples/large_hash.c

163 lines
4.0 KiB
C
Raw Normal View History

/* Creation date: 2005-06-26 00:41:47
* Authors: Don
* Change log:
*/
#include "cfuhash.h"
2013-03-05 04:17:23 +00:00
#include "cfutimer.h"
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <pthread.h>
static
void free_data(void *data) {
free(data);
}
static char *
dup_str(const char *str) {
size_t len = strlen(str);
char *ns = (char *)calloc(len + 1, 1);
memcpy(ns, str, len);
return ns;
}
static u_int32_t
hash_func1(const void *key, size_t length) {
size_t i = length;
unsigned int hash = 0;
char *s = (char *)key;
while (i--) hash = hash * 33 + *s++;
return hash;
}
/* From libtc */
#define mix(a,b,c) \
{ \
a -= b; a -= c; a ^= (c>>13); \
b -= c; b -= a; b ^= (a<<8); \
c -= a; c -= b; c ^= (b>>13); \
a -= b; a -= c; a ^= (c>>12); \
b -= c; b -= a; b ^= (a<<16); \
c -= a; c -= b; c ^= (b>>5); \
a -= b; a -= c; a ^= (c>>3); \
b -= c; b -= a; b ^= (a<<10); \
c -= a; c -= b; c ^= (b>>15); \
}
typedef u_int32_t ub4;
static unsigned int
hash_func_tc(const void *key, size_t length)
{
register ub4 a,b,c,len;
const char *k = key;
/* Set up the internal state */
len = length;
a = b = 0x9e3779b9; /* the golden ratio; an arbitrary value */
c = 0; /* the previous hash value */
/*---------------------------------------- handle most of the key */
while(len >= 12){
a += (k[0] +((ub4)k[1]<<8) +((ub4)k[2]<<16) +((ub4)k[3]<<24));
b += (k[4] +((ub4)k[5]<<8) +((ub4)k[6]<<16) +((ub4)k[7]<<24));
c += (k[8] +((ub4)k[9]<<8) +((ub4)k[10]<<16)+((ub4)k[11]<<24));
mix(a,b,c);
k += 12; len -= 12;
}
/*------------------------------------- handle the last 11 bytes */
c += length;
switch(len){ /* all the case statements fall through */
case 11: c+=((ub4)k[10]<<24);
case 10: c+=((ub4)k[9]<<16);
case 9 : c+=((ub4)k[8]<<8);
/* the first byte of c is reserved for the length */
case 8 : b+=((ub4)k[7]<<24);
case 7 : b+=((ub4)k[6]<<16);
case 6 : b+=((ub4)k[5]<<8);
case 5 : b+=k[4];
case 4 : a+=((ub4)k[3]<<24);
case 3 : a+=((ub4)k[2]<<16);
case 2 : a+=((ub4)k[1]<<8);
case 1 : a+=k[0];
/* case 0: nothing left to add */
}
mix(a,b,c);
/*-------------------------------------------- report the result */
return c;
}
/* End of code from Jenkins */
static int
time_it(cfuhash_function_t hf, double *elapsed_time, u_int32_t num_tests) {
cfuhash_table_t *hash = cfuhash_new_with_initial_size(30);
char key[32];
char value[32];
size_t i;
size_t used;
size_t num_buckets;
size_t num_entries;
2013-03-05 04:17:23 +00:00
cfutimer_t *timer = cfutimer_new();
/* freeze the hash so that it won't shrink while we put in all the data */
cfuhash_set_flag(hash, CFUHASH_FROZEN_UNTIL_GROWS);
cfuhash_set_hash_function(hash, hf);
2013-03-05 04:17:23 +00:00
cfutimer_start(timer);
for (i = 0; i < num_tests; i++) {
sprintf(key, "%lu", 15000000 - i);
sprintf(value, "value%lu", i);
cfuhash_put(hash, key, dup_str(value));
}
2013-03-05 04:17:23 +00:00
cfutimer_stop(timer);
*elapsed_time = cfutimer_elapsed(timer);
cfutimer_free(timer);
used = cfuhash_num_buckets_used(hash);
num_buckets = cfuhash_num_buckets(hash);
num_entries = cfuhash_num_entries(hash);
printf("%lu entries, %lu/%lu buckets (%.2f%%), %.2f%% threshold check\n", num_entries, used, num_buckets, 100.0 * (float)used/(float)num_buckets, 100.0 * (float)num_entries/(float)num_buckets);
cfuhash_destroy_with_free_fn(hash, free_data);
return 0;
}
int main(int argc, char **argv) {
double elapsed_time = 0;
u_int32_t num_tests = 3000000;
argc = argc;
argv = argv;
printf("mutex is %lu bytes\n", sizeof(pthread_mutex_t));
printf("default:\n");
time_it(NULL, &elapsed_time, num_tests);
printf("%.3f seconds\n", elapsed_time);
printf("\n");
fflush(stdout);
printf("hash_func1:\n");
time_it(hash_func1, &elapsed_time, num_tests);
printf("%.3f seconds\n", elapsed_time);
printf("\n");
fflush(stdout);
printf("hash_func_tc:\n");
time_it(hash_func_tc, &elapsed_time, num_tests);
printf("%.3f seconds\n", elapsed_time);
printf("\n");
fflush(stdout);
return 1;
}