rpm-build/rpmdb/rpmhash.c

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/**
* \file rpmdb/rpmhash.c
* Hash table implemenation
*/
#include "system.h"
#include "rpmlib.h"
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#include "rpmhash.h"
#include "debug.h"
#include "jhash.h"
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typedef struct hashBucket_s * hashBucket;
/**
*/
struct hashBucket_s {
hashBucket next; /*!< pointer to next item in bucket */
const void *key; /*!< hash key */
unsigned int dataCount; /*!< data entries */
const void *data[1]; /*!< data - grows by resizing whole bucket */
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};
/**
*/
struct hashTable_s {
hashFunctionType fn; /*!< generate hash value for key */
hashEqualityType eq; /*!< compare hash keys for equality */
unsigned int numBuckets; /*!< number of hash buckets */
hashBucket buckets[1]; /*!< hash bucket array */
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};
/**
* 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 inline /*@shared@*/ /*@null@*/
hashBucket findBucket(hashTable ht, const void * key)
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/*@*/
{
unsigned int hash = ht->fn(key) & (ht->numBuckets - 1);
hashBucket b = ht->buckets[hash];
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while (b && b->key && ht->eq(b->key, key))
b = b->next;
return b;
}
int hashEqualityString(const void * key1, const void * key2)
{
return strcmp(key1, key2);
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}
unsigned int hashFunctionString(const void *str)
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{
return jhashString(str);
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}
hashTable htCreate(unsigned int size, hashFunctionType fn, hashEqualityType eq)
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{
hashTable ht;
unsigned int numBuckets = jhashSize(size);
size_t numBytes = sizeof(*ht) + sizeof(ht->buckets[1]) * (numBuckets - 1);
ht = xcalloc(numBytes, 1);
ht->numBuckets = numBuckets;
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/*@-assignexpose@*/
ht->fn = fn;
ht->eq = eq;
/*@=assignexpose@*/
return ht;
}
void htAddEntry(hashTable ht, const void * key, const void * data)
{
unsigned int hash = ht->fn(key) & (ht->numBuckets - 1);
hashBucket b = ht->buckets[hash];
hashBucket *b_addr = ht->buckets + hash;
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while (b && b->key && ht->eq(b->key, key)) {
b_addr = &(b->next);
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b = b->next;
}
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if (b == NULL) {
b = xmalloc(sizeof(*b));
b->key = key;
b->dataCount = 1;
b->data[0] = data;
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b->next = ht->buckets[hash];
ht->buckets[hash] = b;
}
else {
// Bucket_s already contains space for one dataset
b = *b_addr = xrealloc(b, sizeof(*b) + sizeof(b->data[0]) * b->dataCount);
// though increasing dataCount after the resize
b->data[b->dataCount++] = data;
}
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}
hashTable htFree(hashTable ht, hashFreeKeyType freeKey, hashFreeDataType freeData)
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{
hashBucket b, n;
unsigned int i, j;
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for (i = 0; i < ht->numBuckets; i++) {
b = ht->buckets[i];
if (b == NULL)
continue;
ht->buckets[i] = NULL;
do {
n = b->next;
if (freeKey)
b->key = freeKey(b->key);
if (freeData)
for (j = 0; j < b->dataCount; j++)
b->data[j] = freeData(b->data[j]);
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b = _free(b);
} while ((b = n) != NULL);
}
ht = _free(ht);
return NULL;
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}
int htHasEntry(hashTable ht, const void * key)
{
hashBucket b = findBucket(ht, key);
if (b == NULL)
return 0;
return 1;
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}
int htGetEntry(hashTable ht, const void * key, const void *** data,
int * dataCount, const void ** tableKey)
{
hashBucket b = findBucket(ht, key);
if (b == NULL)
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return 1;
if (data)
*data = b->data;
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if (dataCount)
*dataCount = b->dataCount;
if (tableKey)
*tableKey = b->key;
return 0;
}