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/**
* \file rpmdb/rpmhash.c
* Hash table implemenation
*/
#include "system.h"
#include <rpm/rpmlib.h>
#include "rpmdb/rpmhash.h"
#include "debug.h"
typedef const void * voidptr;
typedef struct hashBucket_s * hashBucket;
/**
*/
struct hashBucket_s {
voidptr key; /*!< hash key */
voidptr * data; /*!< pointer to hashed data */
int dataCount; /*!< length of data (0 if unknown) */
hashBucket next; /*!< pointer to next item in bucket */
};
/**
*/
struct hashTable_s {
int numBuckets; /*!< number of hash buckets */
size_t keySize; /*!< size of key (0 if unknown) */
int freeData; /*!< should data be freed when table is destroyed? */
hashBucket * buckets; /*!< hash bucket array */
hashFunctionType fn; /*!< generate hash value for key */
hashEqualityType eq; /*!< compare hash keys for equality */
};
/**
* Find entry in hash table.
* @param ht pointer to hash table
* @param key pointer to key value
* @return pointer to hash bucket of key (or NULL)
*/
static
hashBucket findEntry(hashTable ht, const void * key)
{
unsigned int hash;
hashBucket b;
hash = ht->fn(key) % ht->numBuckets;
b = ht->buckets[hash];
while (b && b->key && ht->eq(b->key, key))
b = b->next;
return b;
}
int hashEqualityString(const void * key1, const void * key2)
{
const char *k1 = (const char *)key1;
const char *k2 = (const char *)key2;
return strcmp(k1, k2);
}
unsigned int hashFunctionString(const void * string)
{
char xorValue = 0;
char sum = 0;
short len;
int i;
const char * chp = string;
len = strlen(string);
for (i = 0; i < len; i++, chp++) {
xorValue ^= *chp;
sum += *chp;
}
return ((((unsigned)len) << 16) + (((unsigned)sum) << 8) + xorValue);
}
hashTable htCreate(int numBuckets, size_t keySize, int freeData,
hashFunctionType fn, hashEqualityType eq)
{
hashTable ht;
ht = xmalloc(sizeof(*ht));
ht->numBuckets = numBuckets;
ht->buckets = xcalloc(numBuckets, sizeof(*ht->buckets));
ht->keySize = keySize;
ht->freeData = freeData;
ht->fn = fn;
ht->eq = eq;
return ht;
}
void htAddEntry(hashTable ht, const void * key, const void * data)
{
unsigned int hash;
hashBucket b;
hash = ht->fn(key) % ht->numBuckets;
b = ht->buckets[hash];
while (b && b->key && ht->eq(b->key, key))
b = b->next;
if (b == NULL) {
b = xmalloc(sizeof(*b));
if (ht->keySize) {
char *k = xmalloc(ht->keySize);
memcpy(k, key, ht->keySize);
b->key = k;
} else {
b->key = key;
}
b->dataCount = 0;
b->next = ht->buckets[hash];
b->data = NULL;
ht->buckets[hash] = b;
}
b->data = xrealloc(b->data, sizeof(*b->data) * (b->dataCount + 1));
b->data[b->dataCount++] = data;
}
hashTable htFree(hashTable ht)
{
hashBucket b, n;
int i;
for (i = 0; i < ht->numBuckets; i++) {
b = ht->buckets[i];
if (b == NULL)
continue;
ht->buckets[i] = NULL;
if (ht->keySize > 0)
b->key = _free(b->key);
do {
n = b->next;
if (b->data) {
if (ht->freeData)
*b->data = _free(*b->data);
b->data = _free(b->data);
}
b = _free(b);
} while ((b = n) != NULL);
}
ht->buckets = _free(ht->buckets);
ht = _free(ht);
return NULL;
}
int htHasEntry(hashTable ht, const void * key)
{
hashBucket b;
if (!(b = findEntry(ht, key))) return 0; else return 1;
}
int htGetEntry(hashTable ht, const void * key, const void *** data,
int * dataCount, const void ** tableKey)
{
hashBucket b;
if ((b = findEntry(ht, key)) == NULL)
return 1;
if (data)
*data = (const void **) b->data;
if (dataCount)
*dataCount = b->dataCount;
if (tableKey)
*tableKey = b->key;
return 0;
}
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