glib/cmph/bmz8.c
Chun-wei Fan 86b7d7cc99 cmph: Remove C99ism and other fixes
...So that it will compile on non-C99 compilers.  The changes are mainly
moving the variable declarations to the start of the resecptive blocks.

Also, replace the use of buflen in chd.c as it might not be defined for all
platforms, instead using packed_cr_size as it seems to represent the value
that is to be printed/displayed by the debugging output.

https://bugzilla.gnome.org/show_bug.cgi?id=681820
2012-10-27 12:06:09 -04:00

648 lines
21 KiB
C

#include "graph.h"
#include "bmz8.h"
#include "cmph_structs.h"
#include "bmz8_structs.h"
#include "hash.h"
#include "vqueue.h"
#include "bitbool.h"
#include <math.h>
#include <stdlib.h>
#include <stdio.h>
#include <assert.h>
#include <string.h>
#include <errno.h>
//#define DEBUG
#include "debug.h"
static int bmz8_gen_edges(cmph_config_t *mph);
static cmph_uint8 bmz8_traverse_critical_nodes(bmz8_config_data_t *bmz8, cmph_uint32 v, cmph_uint8 * biggest_g_value, cmph_uint8 * biggest_edge_value, cmph_uint8 * used_edges, cmph_uint8 * visited);
static cmph_uint8 bmz8_traverse_critical_nodes_heuristic(bmz8_config_data_t *bmz8, cmph_uint32 v, cmph_uint8 * biggest_g_value, cmph_uint8 * biggest_edge_value, cmph_uint8 * used_edges, cmph_uint8 * visited);
static void bmz8_traverse_non_critical_nodes(bmz8_config_data_t *bmz8, cmph_uint8 * used_edges, cmph_uint8 * visited);
bmz8_config_data_t *bmz8_config_new(void)
{
bmz8_config_data_t *bmz8;
bmz8 = (bmz8_config_data_t *)malloc(sizeof(bmz8_config_data_t));
assert(bmz8);
memset(bmz8, 0, sizeof(bmz8_config_data_t));
bmz8->hashfuncs[0] = CMPH_HASH_JENKINS;
bmz8->hashfuncs[1] = CMPH_HASH_JENKINS;
bmz8->g = NULL;
bmz8->graph = NULL;
bmz8->hashes = NULL;
return bmz8;
}
void bmz8_config_destroy(cmph_config_t *mph)
{
bmz8_config_data_t *data = (bmz8_config_data_t *)mph->data;
DEBUGP("Destroying algorithm dependent data\n");
free(data);
}
void bmz8_config_set_hashfuncs(cmph_config_t *mph, CMPH_HASH *hashfuncs)
{
bmz8_config_data_t *bmz8 = (bmz8_config_data_t *)mph->data;
CMPH_HASH *hashptr = hashfuncs;
cmph_uint8 i = 0;
while(*hashptr != CMPH_HASH_COUNT)
{
if (i >= 2) break; //bmz8 only uses two hash functions
bmz8->hashfuncs[i] = *hashptr;
++i, ++hashptr;
}
}
cmph_t *bmz8_new(cmph_config_t *mph, double c)
{
cmph_t *mphf = NULL;
bmz8_data_t *bmz8f = NULL;
cmph_uint8 i;
cmph_uint8 iterations;
cmph_uint8 iterations_map = 20;
cmph_uint8 *used_edges = NULL;
cmph_uint8 restart_mapping = 0;
cmph_uint8 * visited = NULL;
bmz8_config_data_t *bmz8 = (bmz8_config_data_t *)mph->data;
if (mph->key_source->nkeys >= 256)
{
if (mph->verbosity) fprintf(stderr, "The number of keys in BMZ8 must be lower than 256.\n");
return NULL;
}
if (c == 0) c = 1.15; // validating restrictions over parameter c.
DEBUGP("c: %f\n", c);
bmz8->m = (cmph_uint8) mph->key_source->nkeys;
bmz8->n = (cmph_uint8) ceil(c * mph->key_source->nkeys);
DEBUGP("m (edges): %u n (vertices): %u c: %f\n", bmz8->m, bmz8->n, c);
bmz8->graph = graph_new(bmz8->n, bmz8->m);
DEBUGP("Created graph\n");
bmz8->hashes = (hash_state_t **)malloc(sizeof(hash_state_t *)*3);
for(i = 0; i < 3; ++i) bmz8->hashes[i] = NULL;
do
{
// Mapping step
cmph_uint8 biggest_g_value = 0;
cmph_uint8 biggest_edge_value = 1;
iterations = 100;
if (mph->verbosity)
{
fprintf(stderr, "Entering mapping step for mph creation of %u keys with graph sized %u\n", bmz8->m, bmz8->n);
}
while(1)
{
int ok;
DEBUGP("hash function 1\n");
bmz8->hashes[0] = hash_state_new(bmz8->hashfuncs[0], bmz8->n);
DEBUGP("hash function 2\n");
bmz8->hashes[1] = hash_state_new(bmz8->hashfuncs[1], bmz8->n);
DEBUGP("Generating edges\n");
ok = bmz8_gen_edges(mph);
if (!ok)
{
--iterations;
hash_state_destroy(bmz8->hashes[0]);
bmz8->hashes[0] = NULL;
hash_state_destroy(bmz8->hashes[1]);
bmz8->hashes[1] = NULL;
DEBUGP("%u iterations remaining\n", iterations);
if (mph->verbosity)
{
fprintf(stderr, "simple graph creation failure - %u iterations remaining\n", iterations);
}
if (iterations == 0) break;
}
else break;
}
if (iterations == 0)
{
graph_destroy(bmz8->graph);
return NULL;
}
// Ordering step
if (mph->verbosity)
{
fprintf(stderr, "Starting ordering step\n");
}
graph_obtain_critical_nodes(bmz8->graph);
// Searching step
if (mph->verbosity)
{
fprintf(stderr, "Starting Searching step.\n");
fprintf(stderr, "\tTraversing critical vertices.\n");
}
DEBUGP("Searching step\n");
visited = (cmph_uint8 *)malloc((size_t)bmz8->n/8 + 1);
memset(visited, 0, (size_t)bmz8->n/8 + 1);
used_edges = (cmph_uint8 *)malloc((size_t)bmz8->m/8 + 1);
memset(used_edges, 0, (size_t)bmz8->m/8 + 1);
free(bmz8->g);
bmz8->g = (cmph_uint8 *)calloc((size_t)bmz8->n, sizeof(cmph_uint8));
assert(bmz8->g);
for (i = 0; i < bmz8->n; ++i) // critical nodes
{
if (graph_node_is_critical(bmz8->graph, i) && (!GETBIT(visited,i)))
{
if(c > 1.14) restart_mapping = bmz8_traverse_critical_nodes(bmz8, i, &biggest_g_value, &biggest_edge_value, used_edges, visited);
else restart_mapping = bmz8_traverse_critical_nodes_heuristic(bmz8, i, &biggest_g_value, &biggest_edge_value, used_edges, visited);
if(restart_mapping) break;
}
}
if(!restart_mapping)
{
if (mph->verbosity)
{
fprintf(stderr, "\tTraversing non critical vertices.\n");
}
bmz8_traverse_non_critical_nodes(bmz8, used_edges, visited); // non_critical_nodes
}
else
{
iterations_map--;
if (mph->verbosity) fprintf(stderr, "Restarting mapping step. %u iterations remaining.\n", iterations_map);
}
free(used_edges);
free(visited);
}while(restart_mapping && iterations_map > 0);
graph_destroy(bmz8->graph);
bmz8->graph = NULL;
if (iterations_map == 0)
{
return NULL;
}
mphf = (cmph_t *)malloc(sizeof(cmph_t));
mphf->algo = mph->algo;
bmz8f = (bmz8_data_t *)malloc(sizeof(bmz8_data_t));
bmz8f->g = bmz8->g;
bmz8->g = NULL; //transfer memory ownership
bmz8f->hashes = bmz8->hashes;
bmz8->hashes = NULL; //transfer memory ownership
bmz8f->n = bmz8->n;
bmz8f->m = bmz8->m;
mphf->data = bmz8f;
mphf->size = bmz8->m;
DEBUGP("Successfully generated minimal perfect hash\n");
if (mph->verbosity)
{
fprintf(stderr, "Successfully generated minimal perfect hash function\n");
}
return mphf;
}
static cmph_uint8 bmz8_traverse_critical_nodes(bmz8_config_data_t *bmz8, cmph_uint32 v, cmph_uint8 * biggest_g_value, cmph_uint8 * biggest_edge_value, cmph_uint8 * used_edges, cmph_uint8 * visited)
{
cmph_uint8 next_g;
cmph_uint32 u; /* Auxiliary vertex */
cmph_uint32 lav; /* lookahead vertex */
cmph_uint8 collision;
vqueue_t * q = vqueue_new((cmph_uint32)(graph_ncritical_nodes(bmz8->graph)));
graph_iterator_t it, it1;
DEBUGP("Labelling critical vertices\n");
bmz8->g[v] = (cmph_uint8)(ceil ((double)(*biggest_edge_value)/2) - 1);
SETBIT(visited, v);
next_g = (cmph_uint8)floor((double)(*biggest_edge_value/2)); /* next_g is incremented in the do..while statement*/
vqueue_insert(q, v);
while(!vqueue_is_empty(q))
{
v = vqueue_remove(q);
it = graph_neighbors_it(bmz8->graph, v);
while ((u = graph_next_neighbor(bmz8->graph, &it)) != GRAPH_NO_NEIGHBOR)
{
if (graph_node_is_critical(bmz8->graph, u) && (!GETBIT(visited,u)))
{
collision = 1;
while(collision) // lookahead to resolve collisions
{
next_g = (cmph_uint8)(*biggest_g_value + 1);
it1 = graph_neighbors_it(bmz8->graph, u);
collision = 0;
while((lav = graph_next_neighbor(bmz8->graph, &it1)) != GRAPH_NO_NEIGHBOR)
{
if (graph_node_is_critical(bmz8->graph, lav) && GETBIT(visited,lav))
{
if(next_g + bmz8->g[lav] >= bmz8->m)
{
vqueue_destroy(q);
return 1; // restart mapping step.
}
if (GETBIT(used_edges, (next_g + bmz8->g[lav])))
{
collision = 1;
break;
}
}
}
if (next_g > *biggest_g_value) *biggest_g_value = next_g;
}
// Marking used edges...
it1 = graph_neighbors_it(bmz8->graph, u);
while((lav = graph_next_neighbor(bmz8->graph, &it1)) != GRAPH_NO_NEIGHBOR)
{
if (graph_node_is_critical(bmz8->graph, lav) && GETBIT(visited, lav))
{
SETBIT(used_edges,(next_g + bmz8->g[lav]));
if(next_g + bmz8->g[lav] > *biggest_edge_value)
*biggest_edge_value = (cmph_uint8)(next_g + bmz8->g[lav]);
}
}
bmz8->g[u] = next_g; // Labelling vertex u.
SETBIT(visited,u);
vqueue_insert(q, u);
}
}
}
vqueue_destroy(q);
return 0;
}
static cmph_uint8 bmz8_traverse_critical_nodes_heuristic(bmz8_config_data_t *bmz8, cmph_uint32 v, cmph_uint8 * biggest_g_value, cmph_uint8 * biggest_edge_value, cmph_uint8 * used_edges, cmph_uint8 * visited)
{
cmph_uint8 next_g;
cmph_uint32 u;
cmph_uint32 lav;
cmph_uint8 collision;
cmph_uint8 * unused_g_values = NULL;
cmph_uint8 unused_g_values_capacity = 0;
cmph_uint8 nunused_g_values = 0;
vqueue_t * q = vqueue_new((cmph_uint32)(graph_ncritical_nodes(bmz8->graph)));
graph_iterator_t it, it1;
DEBUGP("Labelling critical vertices\n");
bmz8->g[v] = (cmph_uint8)(ceil ((double)(*biggest_edge_value)/2) - 1);
SETBIT(visited, v);
next_g = (cmph_uint8)floor((double)(*biggest_edge_value/2));
vqueue_insert(q, v);
while(!vqueue_is_empty(q))
{
v = vqueue_remove(q);
it = graph_neighbors_it(bmz8->graph, v);
while ((u = graph_next_neighbor(bmz8->graph, &it)) != GRAPH_NO_NEIGHBOR)
{
if (graph_node_is_critical(bmz8->graph, u) && (!GETBIT(visited,u)))
{
cmph_uint8 next_g_index = 0;
collision = 1;
while(collision) // lookahead to resolve collisions
{
if (next_g_index < nunused_g_values)
{
next_g = unused_g_values[next_g_index++];
}
else
{
next_g = (cmph_uint8)(*biggest_g_value + 1);
next_g_index = 255;//UINT_MAX;
}
it1 = graph_neighbors_it(bmz8->graph, u);
collision = 0;
while((lav = graph_next_neighbor(bmz8->graph, &it1)) != GRAPH_NO_NEIGHBOR)
{
if (graph_node_is_critical(bmz8->graph, lav) && GETBIT(visited,lav))
{
if(next_g + bmz8->g[lav] >= bmz8->m)
{
vqueue_destroy(q);
free(unused_g_values);
return 1; // restart mapping step.
}
if (GETBIT(used_edges, (next_g + bmz8->g[lav])))
{
collision = 1;
break;
}
}
}
if(collision && (next_g > *biggest_g_value)) // saving the current g value stored in next_g.
{
if(nunused_g_values == unused_g_values_capacity)
{
unused_g_values = (cmph_uint8*)realloc(unused_g_values, ((size_t)(unused_g_values_capacity + BUFSIZ))*sizeof(cmph_uint8));
unused_g_values_capacity += (cmph_uint8)BUFSIZ;
}
unused_g_values[nunused_g_values++] = next_g;
}
if (next_g > *biggest_g_value) *biggest_g_value = next_g;
}
next_g_index--;
if (next_g_index < nunused_g_values) unused_g_values[next_g_index] = unused_g_values[--nunused_g_values];
// Marking used edges...
it1 = graph_neighbors_it(bmz8->graph, u);
while((lav = graph_next_neighbor(bmz8->graph, &it1)) != GRAPH_NO_NEIGHBOR)
{
if (graph_node_is_critical(bmz8->graph, lav) && GETBIT(visited, lav))
{
SETBIT(used_edges,(next_g + bmz8->g[lav]));
if(next_g + bmz8->g[lav] > *biggest_edge_value)
*biggest_edge_value = (cmph_uint8)(next_g + bmz8->g[lav]);
}
}
bmz8->g[u] = next_g; // Labelling vertex u.
SETBIT(visited, u);
vqueue_insert(q, u);
}
}
}
vqueue_destroy(q);
free(unused_g_values);
return 0;
}
static cmph_uint8 next_unused_edge(bmz8_config_data_t *bmz8, cmph_uint8 * used_edges, cmph_uint32 unused_edge_index)
{
while(1)
{
assert(unused_edge_index < bmz8->m);
if(GETBIT(used_edges, unused_edge_index)) unused_edge_index ++;
else break;
}
return (cmph_uint8)unused_edge_index;
}
static void bmz8_traverse(bmz8_config_data_t *bmz8, cmph_uint8 * used_edges, cmph_uint32 v, cmph_uint8 * unused_edge_index, cmph_uint8 * visited)
{
graph_iterator_t it = graph_neighbors_it(bmz8->graph, v);
cmph_uint32 neighbor = 0;
while((neighbor = graph_next_neighbor(bmz8->graph, &it)) != GRAPH_NO_NEIGHBOR)
{
if(GETBIT(visited,neighbor)) continue;
//DEBUGP("Visiting neighbor %u\n", neighbor);
*unused_edge_index = next_unused_edge(bmz8, used_edges, *unused_edge_index);
bmz8->g[neighbor] = (cmph_uint8)(*unused_edge_index - bmz8->g[v]);
//if (bmz8->g[neighbor] >= bmz8->m) bmz8->g[neighbor] += bmz8->m;
SETBIT(visited, neighbor);
(*unused_edge_index)++;
bmz8_traverse(bmz8, used_edges, neighbor, unused_edge_index, visited);
}
}
static void bmz8_traverse_non_critical_nodes(bmz8_config_data_t *bmz8, cmph_uint8 * used_edges, cmph_uint8 * visited)
{
cmph_uint8 i, v1, v2, unused_edge_index = 0;
DEBUGP("Labelling non critical vertices\n");
for(i = 0; i < bmz8->m; i++)
{
v1 = (cmph_uint8)graph_vertex_id(bmz8->graph, i, 0);
v2 = (cmph_uint8)graph_vertex_id(bmz8->graph, i, 1);
if((GETBIT(visited,v1) && GETBIT(visited,v2)) || (!GETBIT(visited,v1) && !GETBIT(visited,v2))) continue;
if(GETBIT(visited,v1)) bmz8_traverse(bmz8, used_edges, v1, &unused_edge_index, visited);
else bmz8_traverse(bmz8, used_edges, v2, &unused_edge_index, visited);
}
for(i = 0; i < bmz8->n; i++)
{
if(!GETBIT(visited,i))
{
bmz8->g[i] = 0;
SETBIT(visited, i);
bmz8_traverse(bmz8, used_edges, i, &unused_edge_index, visited);
}
}
}
static int bmz8_gen_edges(cmph_config_t *mph)
{
cmph_uint8 e;
bmz8_config_data_t *bmz8 = (bmz8_config_data_t *)mph->data;
cmph_uint8 multiple_edges = 0;
DEBUGP("Generating edges for %u vertices\n", bmz8->n);
graph_clear_edges(bmz8->graph);
mph->key_source->rewind(mph->key_source->data);
for (e = 0; e < mph->key_source->nkeys; ++e)
{
cmph_uint8 h1, h2;
cmph_uint32 keylen;
char *key = NULL;
mph->key_source->read(mph->key_source->data, &key, &keylen);
// if (key == NULL)fprintf(stderr, "key = %s -- read BMZ\n", key);
h1 = (cmph_uint8)(hash(bmz8->hashes[0], key, keylen) % bmz8->n);
h2 = (cmph_uint8)(hash(bmz8->hashes[1], key, keylen) % bmz8->n);
if (h1 == h2) if (++h2 >= bmz8->n) h2 = 0;
if (h1 == h2)
{
if (mph->verbosity) fprintf(stderr, "Self loop for key %u\n", e);
mph->key_source->dispose(mph->key_source->data, key, keylen);
return 0;
}
//DEBUGP("Adding edge: %u -> %u for key %s\n", h1, h2, key);
mph->key_source->dispose(mph->key_source->data, key, keylen);
// fprintf(stderr, "key = %s -- dispose BMZ\n", key);
multiple_edges = graph_contains_edge(bmz8->graph, h1, h2);
if (mph->verbosity && multiple_edges) fprintf(stderr, "A non simple graph was generated\n");
if (multiple_edges) return 0; // checking multiple edge restriction.
graph_add_edge(bmz8->graph, h1, h2);
}
return !multiple_edges;
}
int bmz8_dump(cmph_t *mphf, FILE *fd)
{
char *buf = NULL;
cmph_uint32 buflen;
cmph_uint8 two = 2; //number of hash functions
bmz8_data_t *data = (bmz8_data_t *)mphf->data;
register size_t nbytes;
__cmph_dump(mphf, fd);
nbytes = fwrite(&two, sizeof(cmph_uint8), (size_t)1, fd);
hash_state_dump(data->hashes[0], &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->hashes[1], &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->n), sizeof(cmph_uint8), (size_t)1, fd);
nbytes = fwrite(&(data->m), sizeof(cmph_uint8), (size_t)1, fd);
nbytes = fwrite(data->g, sizeof(cmph_uint8)*(data->n), (size_t)1, fd);
if (nbytes == 0 && ferror(fd)) {
fprintf(stderr, "ERROR: %s\n", strerror(errno));
return 0;
}
/* #ifdef DEBUG
fprintf(stderr, "G: ");
for (i = 0; i < data->n; ++i) fprintf(stderr, "%u ", data->g[i]);
fprintf(stderr, "\n");
#endif*/
return 1;
}
void bmz8_load(FILE *f, cmph_t *mphf)
{
cmph_uint8 nhashes;
char *buf = NULL;
cmph_uint32 buflen;
cmph_uint8 i;
register size_t nbytes;
bmz8_data_t *bmz8 = (bmz8_data_t *)malloc(sizeof(bmz8_data_t));
DEBUGP("Loading bmz8 mphf\n");
mphf->data = bmz8;
nbytes = fread(&nhashes, sizeof(cmph_uint8), (size_t)1, f);
bmz8->hashes = (hash_state_t **)malloc(sizeof(hash_state_t *)*(size_t)(nhashes + 1));
bmz8->hashes[nhashes] = NULL;
DEBUGP("Reading %u hashes\n", nhashes);
for (i = 0; i < nhashes; ++i)
{
hash_state_t *state = NULL;
nbytes = fread(&buflen, sizeof(cmph_uint32), (size_t)1, f);
DEBUGP("Hash state has %u bytes\n", buflen);
buf = (char *)malloc((size_t)buflen);
nbytes = fread(buf, (size_t)buflen, (size_t)1, f);
state = hash_state_load(buf, buflen);
bmz8->hashes[i] = state;
free(buf);
}
DEBUGP("Reading m and n\n");
nbytes = fread(&(bmz8->n), sizeof(cmph_uint8), (size_t)1, f);
nbytes = fread(&(bmz8->m), sizeof(cmph_uint8), (size_t)1, f);
bmz8->g = (cmph_uint8 *)malloc(sizeof(cmph_uint8)*bmz8->n);
nbytes = fread(bmz8->g, bmz8->n*sizeof(cmph_uint8), (size_t)1, f);
if (nbytes == 0 && ferror(f)) {
fprintf(stderr, "ERROR: %s\n", strerror(errno));
return;
}
#ifdef DEBUG
fprintf(stderr, "G: ");
for (i = 0; i < bmz8->n; ++i) fprintf(stderr, "%u ", bmz8->g[i]);
fprintf(stderr, "\n");
#endif
return;
}
cmph_uint8 bmz8_search(cmph_t *mphf, const char *key, cmph_uint32 keylen)
{
bmz8_data_t *bmz8 = mphf->data;
cmph_uint8 h1 = (cmph_uint8)(hash(bmz8->hashes[0], key, keylen) % bmz8->n);
cmph_uint8 h2 = (cmph_uint8)(hash(bmz8->hashes[1], key, keylen) % bmz8->n);
DEBUGP("key: %s h1: %u h2: %u\n", key, h1, h2);
if (h1 == h2 && ++h2 > bmz8->n) h2 = 0;
DEBUGP("key: %s g[h1]: %u g[h2]: %u edges: %u\n", key, bmz8->g[h1], bmz8->g[h2], bmz8->m);
return (cmph_uint8)(bmz8->g[h1] + bmz8->g[h2]);
}
void bmz8_destroy(cmph_t *mphf)
{
bmz8_data_t *data = (bmz8_data_t *)mphf->data;
free(data->g);
hash_state_destroy(data->hashes[0]);
hash_state_destroy(data->hashes[1]);
free(data->hashes);
free(data);
free(mphf);
}
/** \fn void bmz8_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 bmz8_pack(cmph_t *mphf, void *packed_mphf)
{
bmz8_data_t *data = (bmz8_data_t *)mphf->data;
cmph_uint8 * ptr = packed_mphf;
CMPH_HASH h2_type;
// packing h1 type
CMPH_HASH h1_type = hash_get_type(data->hashes[0]);
*((cmph_uint32 *) ptr) = h1_type;
ptr += sizeof(cmph_uint32);
// packing h1
hash_state_pack(data->hashes[0], ptr);
ptr += hash_state_packed_size(h1_type);
// packing h2 type
h2_type = hash_get_type(data->hashes[1]);
*((cmph_uint32 *) ptr) = h2_type;
ptr += sizeof(cmph_uint32);
// packing h2
hash_state_pack(data->hashes[1], ptr);
ptr += hash_state_packed_size(h2_type);
// packing n
*ptr++ = data->n;
// packing g
memcpy(ptr, data->g, sizeof(cmph_uint8)*data->n);
}
/** \fn cmph_uint32 bmz8_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 bmz8_packed_size(cmph_t *mphf)
{
bmz8_data_t *data = (bmz8_data_t *)mphf->data;
CMPH_HASH h1_type = hash_get_type(data->hashes[0]);
CMPH_HASH h2_type = hash_get_type(data->hashes[1]);
return (cmph_uint32)(sizeof(CMPH_ALGO) + hash_state_packed_size(h1_type) + hash_state_packed_size(h2_type) +
2*sizeof(cmph_uint32) + sizeof(cmph_uint8) + sizeof(cmph_uint8)*data->n);
}
/** cmph_uint8 bmz8_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_uint8 bmz8_search_packed(void *packed_mphf, const char *key, cmph_uint32 keylen)
{
register cmph_uint8 *h1_ptr = packed_mphf;
register CMPH_HASH h1_type = *((cmph_uint32 *)h1_ptr);
register cmph_uint8 *h2_ptr;
register CMPH_HASH h2_type;
register cmph_uint8 *g_ptr, n, h1, h2;
h1_ptr += 4;
h2_ptr = h1_ptr + hash_state_packed_size(h1_type);
h2_type = *((cmph_uint32 *)h2_ptr);
h2_ptr += 4;
g_ptr = h2_ptr + hash_state_packed_size(h2_type);
n = *g_ptr++;
h1 = (cmph_uint8)(hash_packed(h1_ptr, h1_type, key, keylen) % n);
h2 = (cmph_uint8)(hash_packed(h2_ptr, h2_type, key, keylen) % n);
DEBUGP("key: %s h1: %u h2: %u\n", key, h1, h2);
if (h1 == h2 && ++h2 > n) h2 = 0;
return (cmph_uint8)(g_ptr[h1] + g_ptr[h2]);
}