turbonss/EXAMPLES.t2t

CMPH - Examples


%!includeconf: CONFIG.t2t

Using cmph is quite simple. Take a look in the following examples.

-------------------------------------------------------------------

```
#include <cmph.h>
#include <string.h>
// Create minimal perfect hash function from in-memory vector
int main(int argc, char **argv)
{ 

    // Creating a filled vector
    unsigned int i = 0;
    const char *vector[] = {"aaaaaaaaaa", "bbbbbbbbbb", "cccccccccc", "dddddddddd", "eeeeeeeeee", 
        "ffffffffff", "gggggggggg", "hhhhhhhhhh", "iiiiiiiiii", "jjjjjjjjjj"};
    unsigned int nkeys = 10;
    FILE* mphf_fd = fopen("temp.mph", "w");
    // Source of keys
    cmph_io_adapter_t *source = cmph_io_vector_adapter((char **)vector, nkeys);

    //Create minimal perfect hash function using the brz algorithm.
    cmph_config_t *config = cmph_config_new(source);
    cmph_config_set_algo(config, CMPH_BRZ);
    cmph_config_set_mphf_fd(config, mphf_fd);
    cmph_t *hash = cmph_new(config);
    cmph_config_destroy(config);
    cmph_dump(hash, mphf_fd); 
    cmph_destroy(hash);	
    fclose(mphf_fd);

    //Find key
    mphf_fd = fopen("temp.mph", "r");
    hash = cmph_load(mphf_fd);
    while (i < nkeys) {
        const char *key = vector[i];
        unsigned int id = cmph_search(hash, key, (cmph_uint32)strlen(key));
        fprintf(stderr, "key:%s -- hash:%u\n", key, id);
        i++;
    }

    //Destroy hash
    cmph_destroy(hash);
    cmph_io_vector_adapter_destroy(source);   
    fclose(mphf_fd);
    return 0;
}
```
Download [vector_adapter_ex1.c examples/vector_adapter_ex1.c]. This example does not work in versions below 0.6.
-------------------------------

```
#include <cmph.h>
#include <string.h>
// Create minimal perfect hash function from in-memory vector

#pragma pack(1)
typedef struct {
	cmph_uint32 id;
	char key[11];
	cmph_uint32 year;
} rec_t;
#pragma pack(0)

int main(int argc, char **argv)
{   
    // Creating a filled vector
    unsigned int i = 0;  
    rec_t vector[10] = {{1, "aaaaaaaaaa", 1999}, {2, "bbbbbbbbbb", 2000}, {3, "cccccccccc", 2001},
    			{4, "dddddddddd", 2002}, {5, "eeeeeeeeee", 2003}, {6, "ffffffffff", 2004},
    			{7, "gggggggggg", 2005}, {8, "hhhhhhhhhh", 2006}, {9, "iiiiiiiiii", 2007},
    			{10,"jjjjjjjjjj", 2008}};
    unsigned int nkeys = 10;
    FILE* mphf_fd = fopen("temp_struct_vector.mph", "w");
    // Source of keys
    cmph_io_adapter_t *source = cmph_io_struct_vector_adapter(vector, (cmph_uint32)sizeof(rec_t), (cmph_uint32)sizeof(cmph_uint32), 11, nkeys); 

    //Create minimal perfect hash function using the BDZ algorithm.
    cmph_config_t *config = cmph_config_new(source);
    cmph_config_set_algo(config, CMPH_BDZ);
    cmph_config_set_mphf_fd(config, mphf_fd);
    cmph_t *hash = cmph_new(config);
    cmph_config_destroy(config);
    cmph_dump(hash, mphf_fd); 
    cmph_destroy(hash);	
    fclose(mphf_fd);
   
    //Find key
    mphf_fd = fopen("temp_struct_vector.mph", "r");
    hash = cmph_load(mphf_fd);
    while (i < nkeys) {
      const char *key = vector[i].key;
      unsigned int id = cmph_search(hash, key, 11);
      fprintf(stderr, "key:%s -- hash:%u\n", key, id);
      i++;
    }
    
    //Destroy hash
    cmph_destroy(hash);
    cmph_io_vector_adapter_destroy(source);   
    fclose(mphf_fd);
    return 0;
}
```
Download [struct_vector_adapter_ex3.c examples/struct_vector_adapter_ex3.c]. This example does not work in versions below 0.8.
-------------------------------

```
#include <cmph.h>
#include <stdio.h>
#include <string.h>
 // Create minimal perfect hash function from in-disk keys using BDZ algorithm
int main(int argc, char **argv)
{   
	 //Open file with newline separated list of keys
	FILE * keys_fd = fopen("keys.txt", "r");
	cmph_t *hash = NULL;
	if (keys_fd == NULL) 
	{
	  fprintf(stderr, "File \"keys.txt\" not found\n");
	  exit(1);
	}	
	// Source of keys
	cmph_io_adapter_t *source = cmph_io_nlfile_adapter(keys_fd);

	cmph_config_t *config = cmph_config_new(source);
	cmph_config_set_algo(config, CMPH_BDZ);
	hash = cmph_new(config);
	cmph_config_destroy(config);
   
	//Find key
	const char *key = "jjjjjjjjjj";
	unsigned int id = cmph_search(hash, key, (cmph_uint32)strlen(key));
	fprintf(stderr, "Id:%u\n", id);
	//Destroy hash
	cmph_destroy(hash);
	cmph_io_nlfile_adapter_destroy(source);   
	fclose(keys_fd);
	return 0;
}
```
Download [file_adapter_ex2.c examples/file_adapter_ex2.c] and [keys.txt examples/keys.txt]. This example does not work in versions below 0.8.

%!include: ALGORITHMS.t2t

%!include: FOOTER.t2t

%!include(html): ''GOOGLEANALYTICS.t2t''