text: #include "graph.h"
  #include "bmz.h"
  #include "cmph_structs.h"
  #include "bmz_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>
  
  // #define DEBUG
  #include "debug.h"
  
  static int bmz_gen_edges(cmph_config_t *mph);
  static cmph_uint8 bmz_traverse_critical_nodes(bmz_config_data_t *bmz, cmph_uint32 v, cmph_uint32 * biggest_g_value, cmph_uint32 * biggest_edge_value, cmph_uint8 * used_edges, cmph_uint8 * visited);
  static cmph_uint8 bmz_traverse_critical_nodes_heuristic(bmz_config_data_t *bmz, cmph_uint32 v, cmph_uint32 * biggest_g_value, cmph_uint32 * biggest_edge_value, cmph_uint8 * used_edges, cmph_uint8 * visited);
  static void bmz_traverse_non_critical_nodes(bmz_config_data_t *bmz, cmph_uint8 * used_edges, cmph_uint8 * visited);
  
  bmz_config_data_t *bmz_config_new(void)
  {
  	bmz_config_data_t *bmz = NULL;
  	bmz = (bmz_config_data_t *)malloc(sizeof(bmz_config_data_t));
          if (!bmz) return NULL;
  	memset(bmz, 0, sizeof(bmz_config_data_t));
  	bmz->hashfuncs[0] = CMPH_HASH_JENKINS;
  	bmz->hashfuncs[1] = CMPH_HASH_JENKINS;
  	bmz->g = NULL;
  	bmz->graph = NULL;
  	bmz->hashes = NULL;
  	return bmz;
  }
  
  void bmz_config_destroy(cmph_config_t *mph)
  {
  	bmz_config_data_t *data = (bmz_config_data_t *)mph->data;
  	DEBUGP("Destroying algorithm dependent data\n");
  	free(data);
  }
  
  void bmz_config_set_hashfuncs(cmph_config_t *mph, CMPH_HASH *hashfuncs)
  {
  	bmz_config_data_t *bmz = (bmz_config_data_t *)mph->data;
  	CMPH_HASH *hashptr = hashfuncs;
  	cmph_uint32 i = 0;
  	while(*hashptr != CMPH_HASH_COUNT)
  	{
  		if (i >= 2) break; //bmz only uses two hash functions
  		bmz->hashfuncs[i] = *hashptr;
  		++i, ++hashptr;
  	}
  }
  
  cmph_t *bmz_new(cmph_config_t *mph, double c)
  {
  	cmph_t *mphf = NULL;
  	bmz_data_t *bmzf = NULL;
  	cmph_uint32 i;
  	cmph_uint32 iterations;
  	cmph_uint32 iterations_map = 20;
  	cmph_uint8 *used_edges = NULL;
  	cmph_uint8 restart_mapping = 0;
  	cmph_uint8 * visited = NULL;
  
  	bmz_config_data_t *bmz = (bmz_config_data_t *)mph->data;
  	if (c == 0) c = 1.15; // validating restrictions over parameter c.
  	DEBUGP("c: %f\n", c);
  	bmz->m = mph->key_source->nkeys;
  	bmz->n = (cmph_uint32)ceil(c * mph->key_source->nkeys);
  	DEBUGP("m (edges): %u n (vertices): %u c: %f\n", bmz->m, bmz->n, c);
  	bmz->graph = graph_new(bmz->n, bmz->m);
  	DEBUGP("Created graph\n");
  
  	bmz->hashes = (hash_state_t **)malloc(sizeof(hash_state_t *)*3);
  	for(i = 0; i < 3; ++i) bmz->hashes[i] = NULL;
  
  	do
  	{
  	  // Mapping step
  	  cmph_uint32 biggest_g_value = 0;
  	  cmph_uint32 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", bmz->m, bmz->n);
  	  }
  	  while(1)
  	  {
  		int ok;
  		DEBUGP("hash function 1\n");
  		bmz->hashes[0] = hash_state_new(bmz->hashfuncs[0], bmz->n);
  		DEBUGP("hash function 2\n");
  		bmz->hashes[1] = hash_state_new(bmz->hashfuncs[1], bmz->n);
  		DEBUGP("Generating edges\n");
  		ok = bmz_gen_edges(mph);
  		if (!ok)
  		{
  			--iterations;
  			hash_state_destroy(bmz->hashes[0]);
  			bmz->hashes[0] = NULL;
  			hash_state_destroy(bmz->hashes[1]);
  			bmz->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(bmz->graph);
  		return NULL;
  	  }
  	  // Ordering step
  	  if (mph->verbosity)
  	  {
  		fprintf(stderr, "Starting ordering step\n");
  	  }
  	  graph_obtain_critical_nodes(bmz->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)bmz->n/8 + 1);
  	  memset(visited, 0, (size_t)bmz->n/8 + 1);
  	  used_edges = (cmph_uint8 *)malloc((size_t)bmz->m/8 + 1);
  	  memset(used_edges, 0, (size_t)bmz->m/8 + 1);
  	  free(bmz->g);
  	  bmz->g = (cmph_uint32 *)calloc((size_t)bmz->n, sizeof(cmph_uint32));
  	  assert(bmz->g);
  	  for (i = 0; i < bmz->n; ++i) // critical nodes
  	  {
                  if (graph_node_is_critical(bmz->graph, i) && (!GETBIT(visited,i)))
  		{
  		  if(c > 1.14) restart_mapping = bmz_traverse_critical_nodes(bmz, i, &biggest_g_value, &biggest_edge_value, used_edges, visited);
  		  else restart_mapping = bmz_traverse_critical_nodes_heuristic(bmz, 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");
  		}
  		bmz_traverse_non_critical_nodes(bmz, 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(bmz->graph);
  	bmz->graph = NULL;
  	if (iterations_map == 0)
  	{
  		return NULL;
  	}
          #ifdef DEBUG
          fprintf(stderr, "G: ");
          for (i = 0; i < bmz->n; ++i) fprintf(stderr, "%u ", bmz->g[i]);
          fprintf(stderr, "\n");
          #endif
  
  	mphf = (cmph_t *)malloc(sizeof(cmph_t));
  	mphf->algo = mph->algo;
  	bmzf = (bmz_data_t *)malloc(sizeof(bmz_data_t));
  	bmzf->g = bmz->g;
  	bmz->g = NULL; //transfer memory ownership
  	bmzf->hashes = bmz->hashes;
  	bmz->hashes = NULL; //transfer memory ownership
  	bmzf->n = bmz->n;
  	bmzf->m = bmz->m;
  	mphf->data = bmzf;
  	mphf->size = bmz->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 bmz_traverse_critical_nodes(bmz_config_data_t *bmz, cmph_uint32 v, cmph_uint32 * biggest_g_value, cmph_uint32 * biggest_edge_value, cmph_uint8 * used_edges, cmph_uint8 * visited)
  {
          cmph_uint32 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(bmz->graph)) + 1);
  	graph_iterator_t it, it1;
  
  	DEBUGP("Labelling critical vertices\n");
  	bmz->g[v] = (cmph_uint32)ceil ((double)(*biggest_edge_value)/2) - 1;
  	SETBIT(visited, v);
  	next_g    = (cmph_uint32)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(bmz->graph, v);
  		while ((u = graph_next_neighbor(bmz->graph, &it)) != GRAPH_NO_NEIGHBOR)
  		{
                 	        if (graph_node_is_critical(bmz->graph, u) && (!GETBIT(visited,u)))
  			{
  			        collision = 1;
  			        while(collision) // lookahead to resolve collisions
  				{
   				        next_g = *biggest_g_value + 1;
  					it1 = graph_neighbors_it(bmz->graph, u);
  					collision = 0;
  					while((lav = graph_next_neighbor(bmz->graph, &it1)) != GRAPH_NO_NEIGHBOR)
  					{
    					        if (graph_node_is_critical(bmz->graph, lav) && GETBIT(visited,lav))
  						{
     						        if(next_g + bmz->g[lav] >= bmz->m)
  							{
  							        vqueue_destroy(q);
  								return 1; // restart mapping step.
  							}
  							if (GETBIT(used_edges, (next_g + bmz->g[lav])))
  							{
  							        collision = 1;
  								break;
  							}
  						}
  					}
   					if (next_g > *biggest_g_value) *biggest_g_value = next_g;
  				}
  				// Marking used edges...
  				it1 = graph_neighbors_it(bmz->graph, u);
  				while((lav = graph_next_neighbor(bmz->graph, &it1)) != GRAPH_NO_NEIGHBOR)
  				{
                   		        if (graph_node_is_critical(bmz->graph, lav) && GETBIT(visited, lav))
  					{
                     			        SETBIT(used_edges,(next_g + bmz->g[lav]));
  						if(next_g + bmz->g[lav] > *biggest_edge_value) *biggest_edge_value = next_g + bmz->g[lav];
  					}
  				}
  				bmz->g[u] = next_g; // Labelling vertex u.
  				SETBIT(visited,u);
  			        vqueue_insert(q, u);
  			}
  	        }
  
  	}
  	vqueue_destroy(q);
  	return 0;
  }
  
  static cmph_uint8 bmz_traverse_critical_nodes_heuristic(bmz_config_data_t *bmz, cmph_uint32 v, cmph_uint32 * biggest_g_value, cmph_uint32 * biggest_edge_value, cmph_uint8 * used_edges, cmph_uint8 * visited)
  {
          cmph_uint32 next_g;
  	cmph_uint32 u;   /* Auxiliary vertex */
  	cmph_uint32 lav; /* lookahead vertex */
  	cmph_uint8 collision;
  	cmph_uint32 * unused_g_values = NULL;
  	cmph_uint32 unused_g_values_capacity = 0;
  	cmph_uint32 nunused_g_values = 0;
  	vqueue_t * q = vqueue_new((cmph_uint32)(0.5*graph_ncritical_nodes(bmz->graph))+1);
  	graph_iterator_t it, it1;
  
  	DEBUGP("Labelling critical vertices\n");
  	bmz->g[v] = (cmph_uint32)ceil ((double)(*biggest_edge_value)/2) - 1;
  	SETBIT(visited, v);
  	next_g    = (cmph_uint32)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(bmz->graph, v);
  		while ((u = graph_next_neighbor(bmz->graph, &it)) != GRAPH_NO_NEIGHBOR)
  		{
                 	        if (graph_node_is_critical(bmz->graph, u) && (!GETBIT(visited,u)))
  			{
  			        cmph_uint32 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 = *biggest_g_value + 1;
  						next_g_index = UINT_MAX;
  					}
  					it1 = graph_neighbors_it(bmz->graph, u);
  					collision = 0;
  					while((lav = graph_next_neighbor(bmz->graph, &it1)) != GRAPH_NO_NEIGHBOR)
  					{
    					        if (graph_node_is_critical(bmz->graph, lav) && GETBIT(visited,lav))
  						{
     						        if(next_g + bmz->g[lav] >= bmz->m)
  							{
  							        vqueue_destroy(q);
  								free(unused_g_values);
  								return 1; // restart mapping step.
  							}
  							if (GETBIT(used_edges, (next_g + bmz->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_uint32 *)realloc(unused_g_values, (unused_g_values_capacity + BUFSIZ)*sizeof(cmph_uint32));
  						        unused_g_values_capacity += 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(bmz->graph, u);
  				while((lav = graph_next_neighbor(bmz->graph, &it1)) != GRAPH_NO_NEIGHBOR)
  				{
                   		        if (graph_node_is_critical(bmz->graph, lav) && GETBIT(visited, lav))
  					{
                     			        SETBIT(used_edges,(next_g + bmz->g[lav]));
  						if(next_g + bmz->g[lav] > *biggest_edge_value) *biggest_edge_value = next_g + bmz->g[lav];
  					}
  				}
  				bmz->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_uint32 next_unused_edge(bmz_config_data_t *bmz, cmph_uint8 * used_edges, cmph_uint32 unused_edge_index)
  {
         while(1)
         {
  		assert(unused_edge_index < bmz->m);
  		if(GETBIT(used_edges, unused_edge_index)) unused_edge_index ++;
  		else break;
         }
         return unused_edge_index;
  }
  
  static void bmz_traverse(bmz_config_data_t *bmz, cmph_uint8 * used_edges, cmph_uint32 v, cmph_uint32 * unused_edge_index, cmph_uint8 * visited)
  {
  	graph_iterator_t it = graph_neighbors_it(bmz->graph, v);
  	cmph_uint32 neighbor = 0;
  	while((neighbor = graph_next_neighbor(bmz->graph, &it)) != GRAPH_NO_NEIGHBOR)
  	{
       	        if(GETBIT(visited,neighbor)) continue;
  		//DEBUGP("Visiting neighbor %u\n", neighbor);
  		*unused_edge_index = next_unused_edge(bmz, used_edges, *unused_edge_index);
  		bmz->g[neighbor] = *unused_edge_index - bmz->g[v];
  		//if (bmz->g[neighbor] >= bmz->m) bmz->g[neighbor] += bmz->m;
  		SETBIT(visited, neighbor);
  		(*unused_edge_index)++;
  		bmz_traverse(bmz, used_edges, neighbor, unused_edge_index, visited);
  
  	}
  }
  
  static void bmz_traverse_non_critical_nodes(bmz_config_data_t *bmz, cmph_uint8 * used_edges, cmph_uint8 * visited)
  {
  
  	cmph_uint32 i, v1, v2, unused_edge_index = 0;
  	DEBUGP("Labelling non critical vertices\n");
  	for(i = 0; i < bmz->m; i++)
  	{
  	        v1 = graph_vertex_id(bmz->graph, i, 0);
  		v2 = graph_vertex_id(bmz->graph, i, 1);
  		if((GETBIT(visited,v1) && GETBIT(visited,v2)) || (!GETBIT(visited,v1) && !GETBIT(visited,v2))) continue;				  
  		if(GETBIT(visited,v1)) bmz_traverse(bmz, used_edges, v1, &unused_edge_index, visited);
  	        else bmz_traverse(bmz, used_edges, v2, &unused_edge_index, visited);
  
  	}
  
  	for(i = 0; i < bmz->n; i++)
  	{
  		if(!GETBIT(visited,i))
  		{ 
  		        bmz->g[i] = 0;
  			SETBIT(visited, i);
  			bmz_traverse(bmz, used_edges, i, &unused_edge_index, visited);
  		}
  	}
  
  }
  
  static int bmz_gen_edges(cmph_config_t *mph)
  {
  	cmph_uint32 e;
  	bmz_config_data_t *bmz = (bmz_config_data_t *)mph->data;
  	cmph_uint8 multiple_edges = 0;
  	DEBUGP("Generating edges for %u vertices\n", bmz->n);
  	graph_clear_edges(bmz->graph);
  	mph->key_source->rewind(mph->key_source->data);
  	for (e = 0; e < mph->key_source->nkeys; ++e)
  	{
  		cmph_uint32 h1, h2;
  		cmph_uint32 keylen;
  		char *key = NULL;
  		mph->key_source->read(mph->key_source->data, &key, &keylen);
  
  		h1 = hash(bmz->hashes[0], key, keylen) % bmz->n;
  		h2 = hash(bmz->hashes[1], key, keylen) % bmz->n;
  		if (h1 == h2) if (++h2 >= bmz->n) h2 = 0;
  		DEBUGP("key: %.*s h1: %u h2: %u\n", keylen, key, h1, h2);
  		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, keylen, key);
  		mph->key_source->dispose(mph->key_source->data, key, keylen);
  		multiple_edges = graph_contains_edge(bmz->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(bmz->graph, h1, h2);
  	}
  	return !multiple_edges;
  }
  
  int bmz_dump(cmph_t *mphf, FILE *fd)
  {
  	char *buf = NULL;
  	cmph_uint32 buflen;
  	cmph_uint32 two = 2; //number of hash functions
  	bmz_data_t *data = (bmz_data_t *)mphf->data;
  	register size_t nbytes;
  	__cmph_dump(mphf, fd);
  
  	nbytes = fwrite(&two, sizeof(cmph_uint32), (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_uint32), (size_t)1, fd);
  	nbytes = fwrite(&(data->m), sizeof(cmph_uint32), (size_t)1, fd);
  
  	nbytes = fwrite(data->g, sizeof(cmph_uint32)*(data->n), (size_t)1, fd);
  	#ifdef DEBUG
  	cmph_uint32 i;
  	fprintf(stderr, "G: ");
  	for (i = 0; i < data->n; ++i) fprintf(stderr, "%u ", data->g[i]);
  	fprintf(stderr, "\n");
  	#endif
  	return 1;
  }
  
  void bmz_load(FILE *f, cmph_t *mphf)
  {
  	cmph_uint32 nhashes;
  	char *buf = NULL;
  	cmph_uint32 buflen;
  	cmph_uint32 i;
  	bmz_data_t *bmz = (bmz_data_t *)malloc(sizeof(bmz_data_t));
  	register size_t nbytes;
  	DEBUGP("Loading bmz mphf\n");
  	mphf->data = bmz;
  	nbytes = fread(&nhashes, sizeof(cmph_uint32), (size_t)1, f);
  	bmz->hashes = (hash_state_t **)malloc(sizeof(hash_state_t *)*(nhashes + 1));
  	bmz->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);
  		bmz->hashes[i] = state;
  		free(buf);
  	}
  
  	DEBUGP("Reading m and n\n");
  	nbytes = fread(&(bmz->n), sizeof(cmph_uint32), (size_t)1, f);
  	nbytes = fread(&(bmz->m), sizeof(cmph_uint32), (size_t)1, f);
  
  	bmz->g = (cmph_uint32 *)malloc(sizeof(cmph_uint32)*bmz->n);
  	nbytes = fread(bmz->g, bmz->n*sizeof(cmph_uint32), (size_t)1, f);
  	#ifdef DEBUG
  	fprintf(stderr, "G: ");
  	for (i = 0; i < bmz->n; ++i) fprintf(stderr, "%u ", bmz->g[i]);
  	fprintf(stderr, "\n");
  	#endif
  	return;
  }
  
  
  cmph_uint32 bmz_search(cmph_t *mphf, const char *key, cmph_uint32 keylen)
  {
  	bmz_data_t *bmz = (bmz_data_t *)mphf->data;
  	cmph_uint32 h1 = hash(bmz->hashes[0], key, keylen) % bmz->n;
  	cmph_uint32 h2 = hash(bmz->hashes[1], key, keylen) % bmz->n;
  	DEBUGP("key: %.*s h1: %u h2: %u\n", keylen, key, h1, h2);
  	if (h1 == h2 && ++h2 > bmz->n) h2 = 0;
  	DEBUGP("key: %.*s g[h1]: %u g[h2]: %u edges: %u\n", keylen, key, bmz->g[h1], bmz->g[h2], bmz->m);
  	return bmz->g[h1] + bmz->g[h2];
  }
  void bmz_destroy(cmph_t *mphf)
  {
  	bmz_data_t *data = (bmz_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 bmz_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 bmz_pack(cmph_t *mphf, void *packed_mphf)
  {
  
  	bmz_data_t *data = (bmz_data_t *)mphf->data;
  	cmph_uint8 * ptr = (cmph_uint8 *)packed_mphf;
  
  	// 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
  	CMPH_HASH 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
  	*((cmph_uint32 *) ptr) = data->n;
  	ptr += sizeof(data->n);
  
  	// packing g
  	memcpy(ptr, data->g, sizeof(cmph_uint32)*data->n);
  }
  
  /** \fn cmph_uint32 bmz_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 bmz_packed_size(cmph_t *mphf)
  {
  	bmz_data_t *data = (bmz_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) +
  			3*sizeof(cmph_uint32) + sizeof(cmph_uint32)*data->n);
  }
  
  /** cmph_uint32 bmz_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 bmz_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 n = *g_ptr++;
  
  	register cmph_uint32 h1 = hash_packed(h1_ptr, h1_type, key, keylen) % n;
  	register cmph_uint32 h2 = hash_packed(h2_ptr, h2_type, key, keylen) % n;
  	if (h1 == h2 && ++h2 > n) h2 = 0;
  	return (g_ptr[h1] + g_ptr[h2]);
  }
  