350 lines
9.1 KiB
C
350 lines
9.1 KiB
C
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/*
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* ***************************************************************************
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* NOTE:
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* Merge of the icl_hash.h icl_hash.c files from PLASMA 2.5.2 (October 2013).
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* http://icl.cs.utk.edu/plasma/software/
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* ***************************************************************************
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*
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* Dependency free hash table implementation.
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*
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* This simple hash table implementation should be easy to drop into
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* any other peice of code, it does not depend on anything else :-)
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*/
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/*
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*
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* Aauthor Keith Seymour
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* Aauthor Asim YarKhan
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*/
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#include <cstdlib>
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#include <cstdio>
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#include <cstring>
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#include <cassert>
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#include <limits.h>
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#ifndef icl_hash_h
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#define icl_hash_h
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typedef struct icl_entry_s {
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void* key;
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void *data;
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struct icl_entry_s* next;
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} icl_entry_t;
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typedef struct icl_hash_s {
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int nbuckets;
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int nentries;
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icl_entry_t **buckets;
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unsigned int (*hash_function)(void*);
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int (*hash_key_compare)(void*, void*);
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} icl_hash_t;
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#define icl_hash_foreach(ht, tmpint, tmpent, kp, dp) \
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for (tmpint=0;tmpint<ht->nbuckets; tmpint++) \
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for (tmpent=ht->buckets[tmpint]; \
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tmpent!=NULL&&((kp=tmpent->key)!=NULL)&&((dp=tmpent->data)!=NULL); \
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tmpent=tmpent->next)
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#define BITS_IN_int ( sizeof(int) * CHAR_BIT )
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#define THREE_QUARTERS ((int) ((BITS_IN_int * 3) / 4))
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#define ONE_EIGHTH ((int) (BITS_IN_int / 8))
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#define HIGH_BITS ( ~((unsigned int)(~0) >> ONE_EIGHTH ))
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/**
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* A simple string hash.
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*
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* An adaptation of Peter Weinberger's (PJW) generic hashing
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* algorithm based on Allen Holub's version. Accepts a pointer
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* to a datum to be hashed and returns an unsigned integer.
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* From: Keith Seymour's proxy library code
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*
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* @param[in] key -- the string to be hashed
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*
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* @returns the hash index
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*/
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static inline unsigned int
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hash_pjw(void* key)
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{
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char *datum = (char *)key;
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unsigned int hash_value, i;
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if(!datum) return 0;
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for (hash_value = 0; *datum; ++datum) {
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hash_value = (hash_value << ONE_EIGHTH) + *datum;
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if ((i = hash_value & HIGH_BITS) != 0)
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hash_value = (hash_value ^ (i >> THREE_QUARTERS)) & ~HIGH_BITS;
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}
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return (hash_value);
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}
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static inline int string_compare(void* a, void* b)
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{
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return (strcmp( (char*)a, (char*)b ) == 0);
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}
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/**
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* Create a new hash table.
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*
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* @param[in] nbuckets -- number of buckets to create
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* @param[in] hash_function -- pointer to the hashing function to be used
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* @param[in] hash_key_compare -- pointer to the hash key comparison function to be used
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*
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* @returns pointer to new hash table.
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*/
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static inline icl_hash_t *
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icl_hash_create( int nbuckets, unsigned int (*hash_function)(void*), int (*hash_key_compare)(void*, void*) )
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{
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icl_hash_t *ht;
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int i;
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ht = (icl_hash_t*) malloc(sizeof(icl_hash_t));
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assert(ht!=NULL);
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if(!ht) return NULL;
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ht->nentries = 0;
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ht->buckets = (icl_entry_t**)malloc(nbuckets * sizeof(icl_entry_t*));
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assert(ht->buckets!=NULL);
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if(!ht->buckets) return NULL;
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ht->nbuckets = nbuckets;
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for(i=0;i<ht->nbuckets;i++)
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ht->buckets[i] = NULL;
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ht->hash_function = hash_function ? hash_function : hash_pjw;
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ht->hash_key_compare = hash_key_compare ? hash_key_compare : string_compare;
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return ht;
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}
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/**
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* Search for an entry in a hash table.
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*
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* @param ht -- the hash table to be searched
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* @param key -- the key of the item to search for
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*
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* @returns pointer to the data corresponding to the key.
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* If the key was not found, returns NULL.
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*/
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static inline void *
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icl_hash_find(icl_hash_t *ht, void* key)
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{
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icl_entry_t* curr;
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unsigned int hash_val;
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if(!ht || !key) return NULL;
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hash_val = (* ht->hash_function)(key) % ht->nbuckets;
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for (curr=ht->buckets[hash_val]; curr != NULL; curr=curr->next)
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if ( ht->hash_key_compare(curr->key, key))
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return(curr->data);
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return NULL;
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}
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/**
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* Insert an item into the hash table.
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*
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* @param ht -- the hash table
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* @param key -- the key of the new item
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* @param data -- pointer to the new item's data
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*
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* @returns pointer to the new item. Returns NULL on error.
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*/
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static inline icl_entry_t *
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icl_hash_insert(icl_hash_t *ht, void* key, void *data)
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{
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icl_entry_t *curr;
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unsigned int hash_val;
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if(!ht || !key) return NULL;
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hash_val = (* ht->hash_function)(key) % ht->nbuckets;
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for (curr=ht->buckets[hash_val]; curr != NULL; curr=curr->next)
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if ( ht->hash_key_compare(curr->key, key))
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return(NULL); /* key already exists */
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/* if key was not found */
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curr = (icl_entry_t*)malloc(sizeof(icl_entry_t));
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assert(curr != NULL);
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if(!curr) return NULL;
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curr->key = key;
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curr->data = data;
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curr->next = ht->buckets[hash_val]; /* add at start */
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ht->buckets[hash_val] = curr;
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ht->nentries++;
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return curr;
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}
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/**
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* Replace entry in hash table with the given entry.
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*
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* @param ht -- the hash table
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* @param key -- the key of the new item
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* @param data -- pointer to the new item's data
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* @param olddata -- pointer to the old item's data (set upon return)
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*
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* @returns pointer to the new item. Returns NULL on error.
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*/
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static inline icl_entry_t *
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icl_hash_update_insert(icl_hash_t *ht, void* key, void *data) //, void **olddata)
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{
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icl_entry_t *curr, *prev;
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unsigned int hash_val;
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if(!ht || !key) return NULL;
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hash_val = (* ht->hash_function)(key) % ht->nbuckets;
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/* Scan bucket[hash_val] for key */
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for (prev=NULL,curr=ht->buckets[hash_val]; curr != NULL; prev=curr, curr=curr->next)
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/* If key found, remove node from list, free old key, and setup olddata for the return */
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if ( ht->hash_key_compare(curr->key, key)) {
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/* if (olddata != NULL) { */
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/* *olddata = curr->data; */
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/* free(curr->key); */
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/* } */
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if (prev == NULL)
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ht->buckets[hash_val] = curr->next;
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else
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prev->next = curr->next;
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}
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/* Since key was either not found, or found-and-removed, create and prepend new node */
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curr = (icl_entry_t*)malloc(sizeof(icl_entry_t));
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assert(curr!=NULL);
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if(curr == NULL) return NULL; /* out of memory */
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curr->key = key;
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curr->data = data;
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curr->next = ht->buckets[hash_val]; /* add at start */
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ht->buckets[hash_val] = curr;
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ht->nentries++;
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/* if(olddata!=NULL && *olddata!=NULL) */
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/* *olddata = NULL; */
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return curr;
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}
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/**
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* Free one hash table entry located by key (key and data are freed using functions).
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*
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* @param ht -- the hash table to be freed
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* @param key -- the key of the new item
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* @param free_key -- pointer to function that frees the key
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* @param free_data -- pointer to function that frees the data
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*
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* @returns 0 on success, -1 on failure.
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*/
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static inline int icl_hash_delete(icl_hash_t *ht, void* key, void (*free_key)(void*), void (*free_data)(void*))
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{
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icl_entry_t *curr, *prev;
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unsigned int hash_val;
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if(!ht || !key) return -1;
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hash_val = (* ht->hash_function)(key) % ht->nbuckets;
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prev = NULL;
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for (curr=ht->buckets[hash_val]; curr != NULL; ) {
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if ( ht->hash_key_compare(curr->key, key)) {
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if (prev == NULL) {
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ht->buckets[hash_val] = curr->next;
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} else {
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prev->next = curr->next;
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}
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if (*free_key && curr->key) (*free_key)(curr->key);
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if (*free_data && curr->data) (*free_data)(curr->data);
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ht->nentries++;
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free(curr);
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return 0;
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}
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prev = curr;
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curr = curr->next;
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}
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return -1;
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}
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/**
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* Free hash table structures (key and data are freed using functions).
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*
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* @param ht -- the hash table to be freed
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* @param free_key -- pointer to function that frees the key
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* @param free_data -- pointer to function that frees the data
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*
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* @returns 0 on success, -1 on failure.
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*/
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static inline int
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icl_hash_destroy(icl_hash_t *ht, void (*free_key)(void*), void (*free_data)(void*))
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{
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icl_entry_t *bucket, *curr, *next;
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int i;
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if(!ht) return -1;
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for (i=0; i<ht->nbuckets; i++) {
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bucket = ht->buckets[i];
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for (curr=bucket; curr!=NULL; ) {
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next=curr->next;
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if (*free_key && curr->key) (*free_key)(curr->key);
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if (*free_data && curr->data) (*free_data)(curr->data);
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free(curr);
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curr=next;
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}
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}
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if(ht->buckets) free(ht->buckets);
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if(ht) free(ht);
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return 0;
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}
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#if 0
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/**
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* Dump the hash table's contents to the given file pointer.
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*
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* @param stream -- the file to which the hash table should be dumped
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* @param ht -- the hash table to be dumped
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*
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* @returns 0 on success, -1 on failure.
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*/
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static inline int
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icl_hash_dump(FILE* stream, icl_hash_t* ht)
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{
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icl_entry_t *bucket, *curr;
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int i;
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if(!ht) return -1;
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for(i=0; i<ht->nbuckets; i++) {
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bucket = ht->buckets[i];
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for(curr=bucket; curr!=NULL; ) {
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if(curr->key)
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fprintf(stream, "icl_hash_dump: %s: %p\n", (char *)curr->key, curr->data);
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curr=curr->next;
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}
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}
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return 0;
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}
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#endif
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#endif /* icl_hash_h */
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