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#include <ccan/hash/hash.h>
#include <ccan/tap/tap.h>
#include <ccan/hash/hash.c>
#include <stdbool.h>
#include <string.h>
#define ARRAY_WORDS 5
int main(int argc, char *argv[])
{
unsigned int i, j, k;
uint32_t array[ARRAY_WORDS], val;
char array2[sizeof(array) + sizeof(uint32_t)];
uint32_t results[256];
/* Initialize array. */
for (i = 0; i < ARRAY_WORDS; i++)
array[i] = i;
plan_tests(39);
/* Hash should be the same, indep of memory alignment. */
val = hash(array, ARRAY_WORDS, 0);
for (i = 0; i < sizeof(uint32_t); i++) {
memcpy(array2 + i, array, sizeof(array));
ok(hash(array2 + i, ARRAY_WORDS, 0) != val,
"hash matched at offset %i", i);
}
/* Hash of random values should have random distribution:
* check one byte at a time. */
for (i = 0; i < sizeof(uint32_t); i++) {
unsigned int lowest = -1U, highest = 0;
memset(results, 0, sizeof(results));
for (j = 0; j < 256000; j++) {
for (k = 0; k < ARRAY_WORDS; k++)
array[k] = random();
results[(hash(array, ARRAY_WORDS, 0) >> i*8)&0xFF]++;
}
for (j = 0; j < 256; j++) {
if (results[j] < lowest)
lowest = results[j];
if (results[j] > highest)
highest = results[j];
}
/* Expect within 20% */
ok(lowest > 800, "Byte %i lowest %i", i, lowest);
ok(highest < 1200, "Byte %i highest %i", i, highest);
diag("Byte %i, range %u-%u", i, lowest, highest);
}
/* Hash of random values should have random distribution:
* check one byte at a time. */
for (i = 0; i < sizeof(uint64_t); i++) {
unsigned int lowest = -1U, highest = 0;
memset(results, 0, sizeof(results));
for (j = 0; j < 256000; j++) {
for (k = 0; k < ARRAY_WORDS; k++)
array[k] = random();
results[(hash64(array, sizeof(array)/sizeof(uint64_t),
0) >> i*8)&0xFF]++;
}
for (j = 0; j < 256; j++) {
if (results[j] < lowest)
lowest = results[j];
if (results[j] > highest)
highest = results[j];
}
/* Expect within 20% */
ok(lowest > 800, "Byte %i lowest %i", i, lowest);
ok(highest < 1200, "Byte %i highest %i", i, highest);
diag("Byte %i, range %u-%u", i, lowest, highest);
}
/* Hash of pointer values should also have random distribution. */
for (i = 0; i < sizeof(uint32_t); i++) {
unsigned int lowest = -1U, highest = 0;
char *p = malloc(256000);
memset(results, 0, sizeof(results));
for (j = 0; j < 256000; j++)
results[(hash_pointer(p + j, 0) >> i*8)&0xFF]++;
free(p);
for (j = 0; j < 256; j++) {
if (results[j] < lowest)
lowest = results[j];
if (results[j] > highest)
highest = results[j];
}
/* Expect within 20% */
ok(lowest > 800, "hash_pointer byte %i lowest %i", i, lowest);
ok(highest < 1200, "hash_pointer byte %i highest %i",
i, highest);
diag("hash_pointer byte %i, range %u-%u", i, lowest, highest);
}
if (sizeof(long) == sizeof(uint32_t))
ok1(hashl(array, ARRAY_WORDS, 0)
== hash(array, ARRAY_WORDS, 0));
else
ok1(hashl(array, ARRAY_WORDS, 0)
== hash64(array, ARRAY_WORDS, 0));
/* String hash: weak, so only test bottom byte */
for (i = 0; i < 1; i++) {
unsigned int num = 0, cursor, lowest = -1U, highest = 0;
char p[5];
memset(results, 0, sizeof(results));
memset(p, 'A', sizeof(p));
p[sizeof(p)-1] = '\0';
for (;;) {
for (cursor = 0; cursor < sizeof(p)-1; cursor++) {
p[cursor]++;
if (p[cursor] <= 'z')
break;
p[cursor] = 'A';
}
if (cursor == sizeof(p)-1)
break;
results[(hash_string(p) >> i*8)&0xFF]++;
num++;
}
for (j = 0; j < 256; j++) {
if (results[j] < lowest)
lowest = results[j];
if (results[j] > highest)
highest = results[j];
}
/* Expect within 20% */
ok(lowest > 35000, "hash_pointer byte %i lowest %i", i, lowest);
ok(highest < 53000, "hash_pointer byte %i highest %i",
i, highest);
diag("hash_pointer byte %i, range %u-%u", i, lowest, highest);
}
return exit_status();
}
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