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turbonss/src/fch.c

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#include "fch.h"
#include "cmph_structs.h"
#include "fch_structs.h"
#include "hash.h"
#include "bitbool.h"
#include "fch_buckets.h"
#include <math.h>
#include <stdlib.h>
#include <stdio.h>
#include <assert.h>
#include <string.h>
#define INDEX 0 /* alignment index within a bucket */
//#define DEBUG
#include "debug.h"
static fch_buckets_t * mapping(cmph_config_t *mph);
static cmph_uint32 * ordering(fch_buckets_t * buckets);
static cmph_uint8 check_for_collisions_h2(fch_config_data_t *fch, fch_buckets_t * buckets, cmph_uint32 *sorted_indexes);
static void permut(cmph_uint32 * vector, cmph_uint32 n);
static cmph_uint8 searching(fch_config_data_t *fch, fch_buckets_t *buckets, cmph_uint32 *sorted_indexes);
fch_config_data_t *fch_config_new()
{
fch_config_data_t *fch;
fch = (fch_config_data_t *)malloc(sizeof(fch_config_data_t));
if (!fch) return NULL;
memset(fch, 0, sizeof(fch_config_data_t));
fch->hashfuncs[0] = CMPH_HASH_JENKINS;
fch->hashfuncs[1] = CMPH_HASH_JENKINS;
fch->m = fch->b = 0;
fch->c = fch->p1 = fch->p2 = 0.0;
fch->g = NULL;
fch->h1 = NULL;
fch->h2 = NULL;
return fch;
}
void fch_config_destroy(cmph_config_t *mph)
{
fch_config_data_t *data = (fch_config_data_t *)mph->data;
//DEBUGP("Destroying algorithm dependent data\n");
free(data);
}
void fch_config_set_hashfuncs(cmph_config_t *mph, CMPH_HASH *hashfuncs)
{
fch_config_data_t *fch = (fch_config_data_t *)mph->data;
CMPH_HASH *hashptr = hashfuncs;
cmph_uint32 i = 0;
while(*hashptr != CMPH_HASH_COUNT)
{
if (i >= 2) break; //fch only uses two hash functions
fch->hashfuncs[i] = *hashptr;
++i, ++hashptr;
}
}
cmph_uint32 mixh10h11h12(cmph_uint32 b, double p1, double p2, cmph_uint32 initial_index)
{
register cmph_uint32 int_p2 = (cmph_uint32)p2;
if (initial_index < p1) initial_index %= int_p2; /* h11 o h10 */
else { /* h12 o h10 */
initial_index %= b;
if(initial_index < p2) initial_index += int_p2;
}
return initial_index;
}
cmph_uint32 fch_calc_b(double c, cmph_uint32 m)
{
return (cmph_uint32)ceil((c*m)/(log((double)m)/log(2.0) + 1));
}
double fch_calc_p1(cmph_uint32 m)
{
return ceil(0.55*m);
}
double fch_calc_p2(cmph_uint32 b)
{
return ceil(0.3*b);
}
static fch_buckets_t * mapping(cmph_config_t *mph)
{
cmph_uint32 i = 0;
fch_buckets_t *buckets = NULL;
fch_config_data_t *fch = (fch_config_data_t *)mph->data;
if (fch->h1) hash_state_destroy(fch->h1);
fch->h1 = hash_state_new(fch->hashfuncs[0], fch->m);
fch->b = fch_calc_b(fch->c, fch->m);
fch->p1 = fch_calc_p1(fch->m);
fch->p2 = fch_calc_p2(fch->b);
//DEBUGP("b:%u p1:%f p2:%f\n", fch->b, fch->p1, fch->p2);
buckets = fch_buckets_new(fch->b);
mph->key_source->rewind(mph->key_source->data);
for(i = 0; i < fch->m; i++)
{
cmph_uint32 h1, keylen;
char *key = NULL;
mph->key_source->read(mph->key_source->data, &key, &keylen);
h1 = hash(fch->h1, key, keylen) % fch->m;
h1 = mixh10h11h12 (fch->b, fch->p1, fch->p2, h1);
fch_buckets_insert(buckets, h1, key, keylen);
key = NULL; // transger memory ownership
}
return buckets;
}
// returns the buckets indexes sorted by their sizes.
static cmph_uint32 * ordering(fch_buckets_t * buckets)
{
return fch_buckets_get_indexes_sorted_by_size(buckets);
}
/* Check whether function h2 causes collisions among the keys of each bucket */
static cmph_uint8 check_for_collisions_h2(fch_config_data_t *fch, fch_buckets_t * buckets, cmph_uint32 *sorted_indexes)
{
//cmph_uint32 max_size = fch_buckets_get_max_size(buckets);
cmph_uint8 * hashtable = (cmph_uint8 *)calloc((size_t)fch->m, sizeof(cmph_uint8));
cmph_uint32 nbuckets = fch_buckets_get_nbuckets(buckets);
cmph_uint32 i = 0, index = 0, j =0;
for (i = 0; i < nbuckets; i++)
{
cmph_uint32 nkeys = fch_buckets_get_size(buckets, sorted_indexes[i]);
memset(hashtable, 0, (size_t)fch->m);
//DEBUGP("bucket %u -- nkeys: %u\n", i, nkeys);
for (j = 0; j < nkeys; j++)
{
char * key = fch_buckets_get_key(buckets, sorted_indexes[i], j);
cmph_uint32 keylen = fch_buckets_get_keylength(buckets, sorted_indexes[i], j);
index = hash(fch->h2, key, keylen) % fch->m;
if(hashtable[index]) { // collision detected
free(hashtable);
return 1;
}
hashtable[index] = 1;
}
}
free(hashtable);
return 0;
}
static void permut(cmph_uint32 * vector, cmph_uint32 n)
{
cmph_uint32 i, j, b;
for (i = 0; i < n; i++) {
j = (cmph_uint32) rand() % n;
b = vector[i];
vector[i] = vector[j];
vector[j] = b;
}
}
static cmph_uint8 searching(fch_config_data_t *fch, fch_buckets_t *buckets, cmph_uint32 *sorted_indexes)
{
cmph_uint32 * random_table = (cmph_uint32 *) calloc((size_t)fch->m, sizeof(cmph_uint32));
cmph_uint32 * map_table = (cmph_uint32 *) calloc((size_t)fch->m, sizeof(cmph_uint32));
cmph_uint32 iteration_to_generate_h2 = 0;
cmph_uint32 searching_iterations = 0;
cmph_uint8 restart = 0;
cmph_uint32 nbuckets = fch_buckets_get_nbuckets(buckets);
cmph_uint32 i, j, z, counter = 0, filled_count = 0;
if (fch->g) free (fch->g);
fch->g = (cmph_uint32 *) calloc((size_t)fch->b, sizeof(cmph_uint32));
//DEBUGP("max bucket size: %u\n", fch_buckets_get_max_size(buckets));
for(i = 0; i < fch->m; i++)
{
random_table[i] = i;
}
permut(random_table, fch->m);
for(i = 0; i < fch->m; i++)
{
map_table[random_table[i]] = i;
}
do {
if (fch->h2) hash_state_destroy(fch->h2);
fch->h2 = hash_state_new(fch->hashfuncs[1], fch->m);
restart = check_for_collisions_h2(fch, buckets, sorted_indexes);
filled_count = 0;
if (!restart)
{
searching_iterations++; iteration_to_generate_h2 = 0;
//DEBUGP("searching_iterations: %u\n", searching_iterations);
}
else {
iteration_to_generate_h2++;
//DEBUGP("iteration_to_generate_h2: %u\n", iteration_to_generate_h2);
}
for(i = 0; (i < nbuckets) && !restart; i++) {
cmph_uint32 bucketsize = fch_buckets_get_size(buckets, sorted_indexes[i]);
if (bucketsize == 0)
{
restart = 0; // false
break;
}
else restart = 1; // true
for(z = 0; (z < (fch->m - filled_count)) && restart; z++) {
char * key = fch_buckets_get_key(buckets, sorted_indexes[i], INDEX);
cmph_uint32 keylen = fch_buckets_get_keylength(buckets, sorted_indexes[i], INDEX);
cmph_uint32 h2 = hash(fch->h2, key, keylen) % fch->m;
counter = 0;
restart = 0; // false
fch->g[sorted_indexes[i]] = (fch->m + random_table[filled_count + z] - h2) % fch->m;
//DEBUGP("g[%u]: %u\n", sorted_indexes[i], fch->g[sorted_indexes[i]]);
j = INDEX;
do {
cmph_uint32 index = 0;
key = fch_buckets_get_key(buckets, sorted_indexes[i], j);
keylen = fch_buckets_get_keylength(buckets, sorted_indexes[i], j);
h2 = hash(fch->h2, key, keylen) % fch->m;
index = (h2 + fch->g[sorted_indexes[i]]) % fch->m;
//DEBUGP("key:%s keylen:%u index: %u h2:%u bucketsize:%u\n", key, keylen, index, h2, bucketsize);
if (map_table[index] >= filled_count) {
cmph_uint32 y = map_table[index];
cmph_uint32 ry = random_table[y];
random_table[y] = random_table[filled_count];
random_table[filled_count] = ry;
map_table[random_table[y]] = y;
map_table[random_table[filled_count]] = filled_count;
filled_count++;
counter ++;
}
else {
restart = 1; // true
filled_count = filled_count - counter;
counter = 0;
break;
}
j = (j + 1) % bucketsize;
} while(j % bucketsize != INDEX);
}
//getchar();
}
} while(restart && (searching_iterations < 10) && (iteration_to_generate_h2 < 1000));
free(map_table);
free(random_table);
return restart;
}
cmph_t *fch_new(cmph_config_t *mph, double c)
{
cmph_t *mphf = NULL;
fch_data_t *fchf = NULL;
cmph_uint32 iterations = 100;
cmph_uint8 restart_mapping = 0;
fch_buckets_t * buckets = NULL;
cmph_uint32 * sorted_indexes = NULL;
fch_config_data_t *fch = (fch_config_data_t *)mph->data;
fch->m = mph->key_source->nkeys;
//DEBUGP("m: %f\n", fch->m);
if (c <= 2) c = 2.6; // validating restrictions over parameter c.
fch->c = c;
//DEBUGP("c: %f\n", fch->c);
fch->h1 = NULL;
fch->h2 = NULL;
fch->g = NULL;
do
{
if (mph->verbosity)
{
fprintf(stderr, "Entering mapping step for mph creation of %u keys\n", fch->m);
}
if (buckets) fch_buckets_destroy(buckets, mph);
buckets = mapping(mph);
if (mph->verbosity)
{
fprintf(stderr, "Starting ordering step\n");
}
if (sorted_indexes) free (sorted_indexes);
sorted_indexes = ordering(buckets);
if (mph->verbosity)
{
fprintf(stderr, "Starting searching step.\n");
}
restart_mapping = searching(fch, buckets, sorted_indexes);
iterations--;
} while(restart_mapping && iterations > 0);
if (buckets) fch_buckets_destroy(buckets, mph);
if (sorted_indexes) free (sorted_indexes);
if (iterations == 0) return NULL;
mphf = (cmph_t *)malloc(sizeof(cmph_t));
mphf->algo = mph->algo;
fchf = (fch_data_t *)malloc(sizeof(fch_data_t));
fchf->g = fch->g;
fch->g = NULL; //transfer memory ownership
fchf->h1 = fch->h1;
fch->h1 = NULL; //transfer memory ownership
fchf->h2 = fch->h2;
fch->h2 = NULL; //transfer memory ownership
fchf->p2 = fch->p2;
fchf->p1 = fch->p1;
fchf->b = fch->b;
fchf->c = fch->c;
fchf->m = fch->m;
mphf->data = fchf;
mphf->size = fch->m;
//DEBUGP("Successfully generated minimal perfect hash\n");
if (mph->verbosity)
{
fprintf(stderr, "Successfully generated minimal perfect hash function\n");
}
return mphf;
}
int fch_dump(cmph_t *mphf, FILE *fd)
{
char *buf = NULL;
cmph_uint32 buflen;
register size_t nbytes;
fch_data_t *data = (fch_data_t *)mphf->data;
__cmph_dump(mphf, fd);
hash_state_dump(data->h1, &buf, &buflen);
//DEBUGP("Dumping hash state with %u bytes to disk\n", buflen);
nbytes = fwrite(&buflen, sizeof(cmph_uint32), (size_t)1, fd);
nbytes = fwrite(buf, (size_t)buflen, (size_t)1, fd);
free(buf);
hash_state_dump(data->h2, &buf, &buflen);
//DEBUGP("Dumping hash state with %u bytes to disk\n", buflen);
nbytes = fwrite(&buflen, sizeof(cmph_uint32), (size_t)1, fd);
nbytes = fwrite(buf, (size_t)buflen, (size_t)1, fd);
free(buf);
nbytes = fwrite(&(data->m), sizeof(cmph_uint32), (size_t)1, fd);
nbytes = fwrite(&(data->c), sizeof(double), (size_t)1, fd);
nbytes = fwrite(&(data->b), sizeof(cmph_uint32), (size_t)1, fd);
nbytes = fwrite(&(data->p1), sizeof(double), (size_t)1, fd);
nbytes = fwrite(&(data->p2), sizeof(double), (size_t)1, fd);
nbytes = fwrite(data->g, sizeof(cmph_uint32)*(data->b), (size_t)1, fd);
#ifdef DEBUG
cmph_uint32 i;
fprintf(stderr, "G: ");
for (i = 0; i < data->b; ++i) fprintf(stderr, "%u ", data->g[i]);
fprintf(stderr, "\n");
#endif
return 1;
}
void fch_load(FILE *f, cmph_t *mphf)
{
char *buf = NULL;
cmph_uint32 buflen;
register size_t nbytes;
fch_data_t *fch = (fch_data_t *)malloc(sizeof(fch_data_t));
//DEBUGP("Loading fch mphf\n");
mphf->data = fch;
//DEBUGP("Reading h1\n");
fch->h1 = NULL;
nbytes = fread(&buflen, sizeof(cmph_uint32), (size_t)1, f);
//DEBUGP("Hash state of h1 has %u bytes\n", buflen);
buf = (char *)malloc((size_t)buflen);
nbytes = fread(buf, (size_t)buflen, (size_t)1, f);
fch->h1 = hash_state_load(buf, buflen);
free(buf);
//DEBUGP("Loading fch mphf\n");
mphf->data = fch;
//DEBUGP("Reading h2\n");
fch->h2 = NULL;
nbytes = fread(&buflen, sizeof(cmph_uint32), (size_t)1, f);
//DEBUGP("Hash state of h2 has %u bytes\n", buflen);
buf = (char *)malloc((size_t)buflen);
nbytes = fread(buf, (size_t)buflen, (size_t)1, f);
fch->h2 = hash_state_load(buf, buflen);
free(buf);
//DEBUGP("Reading m and n\n");
nbytes = fread(&(fch->m), sizeof(cmph_uint32), (size_t)1, f);
nbytes = fread(&(fch->c), sizeof(double), (size_t)1, f);
nbytes = fread(&(fch->b), sizeof(cmph_uint32), (size_t)1, f);
nbytes = fread(&(fch->p1), sizeof(double), (size_t)1, f);
nbytes = fread(&(fch->p2), sizeof(double), (size_t)1, f);
fch->g = (cmph_uint32 *)malloc(sizeof(cmph_uint32)*fch->b);
nbytes = fread(fch->g, fch->b*sizeof(cmph_uint32), (size_t)1, f);
#ifdef DEBUG
cmph_uint32 i;
fprintf(stderr, "G: ");
for (i = 0; i < fch->b; ++i) fprintf(stderr, "%u ", fch->g[i]);
fprintf(stderr, "\n");
#endif
return;
}
cmph_uint32 fch_search(cmph_t *mphf, const char *key, cmph_uint32 keylen)
{
fch_data_t *fch = (fch_data_t *)mphf->data;
cmph_uint32 h1 = hash(fch->h1, key, keylen) % fch->m;
cmph_uint32 h2 = hash(fch->h2, key, keylen) % fch->m;
h1 = mixh10h11h12 (fch->b, fch->p1, fch->p2, h1);
//DEBUGP("key: %s h1: %u h2: %u g[h1]: %u\n", key, h1, h2, fch->g[h1]);
return (h2 + fch->g[h1]) % fch->m;
}
void fch_destroy(cmph_t *mphf)
{
fch_data_t *data = (fch_data_t *)mphf->data;
free(data->g);
hash_state_destroy(data->h1);
hash_state_destroy(data->h2);
free(data);
free(mphf);
}
/** \fn void fch_pack(cmph_t *mphf, void *packed_mphf);
* \brief Support the ability to pack a perfect hash function into a preallocated contiguous memory space pointed by packed_mphf.
* \param mphf pointer to the resulting mphf
* \param packed_mphf pointer to the contiguous memory area used to store the resulting mphf. The size of packed_mphf must be at least cmph_packed_size()
*/
void fch_pack(cmph_t *mphf, void *packed_mphf)
{
fch_data_t *data = (fch_data_t *)mphf->data;
cmph_uint8 * ptr = (cmph_uint8 *)packed_mphf;
// packing h1 type
CMPH_HASH h1_type = hash_get_type(data->h1);
*((cmph_uint32 *) ptr) = h1_type;
ptr += sizeof(cmph_uint32);
// packing h1
hash_state_pack(data->h1, ptr);
ptr += hash_state_packed_size(h1_type);
// packing h2 type
CMPH_HASH h2_type = hash_get_type(data->h2);
*((cmph_uint32 *) ptr) = h2_type;
ptr += sizeof(cmph_uint32);
// packing h2
hash_state_pack(data->h2, ptr);
ptr += hash_state_packed_size(h2_type);
// packing m
*((cmph_uint32 *) ptr) = data->m;
ptr += sizeof(data->m);
// packing b
*((cmph_uint32 *) ptr) = data->b;
ptr += sizeof(data->b);
// packing p1
*((cmph_uint64 *)ptr) = (cmph_uint64)data->p1;
ptr += sizeof(data->p1);
// packing p2
*((cmph_uint64 *)ptr) = (cmph_uint64)data->p2;
ptr += sizeof(data->p2);
// packing g
memcpy(ptr, data->g, sizeof(cmph_uint32)*(data->b));
}
/** \fn cmph_uint32 fch_packed_size(cmph_t *mphf);
* \brief Return the amount of space needed to pack mphf.
* \param mphf pointer to a mphf
* \return the size of the packed function or zero for failures
*/
cmph_uint32 fch_packed_size(cmph_t *mphf)
{
fch_data_t *data = (fch_data_t *)mphf->data;
CMPH_HASH h1_type = hash_get_type(data->h1);
CMPH_HASH h2_type = hash_get_type(data->h2);
return (cmph_uint32)(sizeof(CMPH_ALGO) + hash_state_packed_size(h1_type) + hash_state_packed_size(h2_type) +
4*sizeof(cmph_uint32) + 2*sizeof(double) + sizeof(cmph_uint32)*(data->b));
}
/** cmph_uint32 fch_search(void *packed_mphf, const char *key, cmph_uint32 keylen);
* \brief Use the packed mphf to do a search.
* \param packed_mphf pointer to the packed mphf
* \param key key to be hashed
* \param keylen key legth in bytes
* \return The mphf value
*/
cmph_uint32 fch_search_packed(void *packed_mphf, const char *key, cmph_uint32 keylen)
{
register cmph_uint8 *h1_ptr = (cmph_uint8 *)packed_mphf;
register CMPH_HASH h1_type = (CMPH_HASH)*((cmph_uint32 *)h1_ptr);
h1_ptr += 4;
register cmph_uint8 *h2_ptr = h1_ptr + hash_state_packed_size(h1_type);
register CMPH_HASH h2_type = (CMPH_HASH)*((cmph_uint32 *)h2_ptr);
h2_ptr += 4;
register cmph_uint32 *g_ptr = (cmph_uint32 *)(h2_ptr + hash_state_packed_size(h2_type));
register cmph_uint32 m = *g_ptr++;
register cmph_uint32 b = *g_ptr++;
register double p1 = (double)(*((cmph_uint64 *)g_ptr));
g_ptr += 2;
register double p2 = (double)(*((cmph_uint64 *)g_ptr));
g_ptr += 2;
register cmph_uint32 h1 = hash_packed(h1_ptr, h1_type, key, keylen) % m;
register cmph_uint32 h2 = hash_packed(h2_ptr, h2_type, key, keylen) % m;
h1 = mixh10h11h12 (b, p1, p2, h1);
return (h2 + g_ptr[h1]) % m;
}
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