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/* Storing keys in hash tables, similar to Perl's associative arrays.
*
*/
#ifndef eslKEYHASH_INCLUDED
#define eslKEYHASH_INCLUDED
#include "esl_config.h"
#include <stdio.h> /* for FILE */
/* ESL_KEYHASH:
* a dynamically resized hash structure;
* contains a hash table and associated data
*
* Each key string is associated with an index i = (0..nkeys-1).
* Key strings are stored in one array, in smem.
* Each key has an offset in this array, key_offset[i].
* Thus key number <i> is at: smem + key_offset[i].
*
* The keys are hashed, and stored in linked lists in
* a hashtable by their index i = (0..nkeys-1), with -1
* as a sentinel for end-of-list.
*
* hashtable[0..hashsize-1] = head of linked list;
* index of first elem in list (0..nkeys-1),
* or -1 if empty.
* nxt[0..nkeys-1] = next elem in list (0..nkeys-1), or -1 if none.
*
* Thus a typical loop, looking for a <key>:
* uint32_t val = jenkins_hash(key, kh->hashsize);
* for (i = kh->hashtable[val]; i != -1; i = kh->nxt[i])
* if (strcmp(key, kh->smem + kh->key_offset[i]) == 0) found_it;
*
*/
typedef struct {
int *hashtable; /* hashtable[0..hashsize-1] = index of first elem, or -1 */
uint32_t hashsize; /* size of the hash table */
int *key_offset; /* key [idx=0..nkeys-1] starts at smem + key_offset[idx] */
int *nxt; /* nxt [idx=0..nkeys-1], next "pointers" in hash table */
int nkeys; /* number of keys stored */
int kalloc; /* number of keys allocated for */
char *smem; /* Array of memory for storing key strings (w/ \0's) */
int salloc; /* current allocated size of <key_mem> */
int sn; /* current used size of key strings, inclusive \0's */
} ESL_KEYHASH;
extern ESL_KEYHASH *esl_keyhash_Create(void);
extern ESL_KEYHASH *esl_keyhash_CreateCustom(uint32_t hashsize, int kalloc, int salloc);
extern ESL_KEYHASH *esl_keyhash_Clone(const ESL_KEYHASH *kh);
extern char * esl_keyhash_Get(const ESL_KEYHASH *kh, int idx);
extern int esl_keyhash_GetNumber(const ESL_KEYHASH *kh);
extern size_t esl_keyhash_Sizeof(const ESL_KEYHASH *kh);
extern int esl_keyhash_Reuse(ESL_KEYHASH *kh);
extern void esl_keyhash_Destroy(ESL_KEYHASH *kh);
extern void esl_keyhash_Dump(FILE *fp, const ESL_KEYHASH *kh);
extern int esl_keyhash_Store ( ESL_KEYHASH *kh, const char *key, esl_pos_t n, int *ret_index);
extern int esl_keyhash_Lookup(const ESL_KEYHASH *kh, const char *key, esl_pos_t n, int *ret_index);
#endif /* eslKEYHASH_INCLUDED */
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