util-hash.c

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/* Copyright (C) 2007-2026 Open Information Security Foundation
 *
 * You can copy, redistribute or modify this Program under the terms of
 * the GNU General Public License version 2 as published by the Free
 * Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * version 2 along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA.
 */
 
/**
 * \file
 *
 * \author Victor Julien <victor@inliniac.net>
 *
 * Chained hash table implementation
 *
 * The 'Free' pointer can be used to have the API free your
 * hashed data. If it's NULL it's the callers responsibility
 */
 
#include "suricata-common.h"
#include "util-hash.h"
#include "util-unittest.h"
#include "util-memcmp.h"
#include "util-debug.h"
 
HashTable* HashTableInit(uint32_t size, uint32_t (*Hash)(struct HashTable_ *, void *, uint16_t), char (*Compare)(void *, uint16_t, void *, uint16_t), void (*Free)(void *)) {
 
    HashTable *ht = NULL;
 
    if (size == 0) {
        goto error;
    }
 
    if (Hash == NULL) {
        //printf("ERROR: HashTableInit no Hash function\n");
        goto error;
    }
 
    /* setup the filter */
    ht = SCCalloc(1, sizeof(HashTable));
    if (unlikely(ht == NULL))
        goto error;
    ht->array_size = size;
    ht->Hash = Hash;
    ht->Free = Free;
 
    if (Compare != NULL)
        ht->Compare = Compare;
    else
        ht->Compare = HashTableDefaultCompare;
 
    /* setup the bitarray */
    ht->array = SCCalloc(ht->array_size, sizeof(HashTableBucket *));
    if (ht->array == NULL)
        goto error;
 
    return ht;
 
error:
    if (ht != NULL) {
        if (ht->array != NULL)
            SCFree(ht->array);
 
        SCFree(ht);
    }
    return NULL;
}
 
HashTable *HashTableInitWithSeed(uint32_t size,
        uint32_t (*Hash)(struct HashTable_ *, void *, uint16_t),
        char (*Compare)(void *, uint16_t, void *, uint16_t), void (*Free)(void *),
        const uint32_t seed)
{
    HashTable *ht = HashTableInit(size, Hash, Compare, Free);
    if (ht != NULL) {
        ht->seed = seed;
    }
    return ht;
}
 
/**
 *  \brief Free a HashTableBucket and return the next bucket
 *  \param ht Pointer to the HashTable
 *  \param htb Pointer to the HashTableBucket to free
 *  \return HashTableBucket* Pointer to the next HashTableBucket or NULL
 */
static HashTableBucket *HashTableBucketFree(HashTable *ht, HashTableBucket *htb)
{
    HashTableBucket *next_hashbucket = htb->next;
    if (ht->Free != NULL)
        ht->Free(htb->data);
    SCFree(htb);
    return next_hashbucket;
}
 
/**
 *  \brief Free a HashTable and all its contents
 *  \details This function will free all the buckets and the array of buckets.
 *  \note If the Free function is set, it will be called for each data item in the hash table.
 *  \param ht Pointer to the HashTable to free
 *  \return void
 */
void HashTableFree(HashTable *ht)
{
    if (ht == NULL)
        return;
 
    /* free the buckets */
    for (uint32_t i = 0; i < ht->array_size; i++) {
        HashTableBucket *hashbucket = ht->array[i];
        while (hashbucket != NULL) {
            hashbucket = HashTableBucketFree(ht, hashbucket);
        }
    }
 
    /* free the array */
    if (ht->array != NULL)
        SCFree(ht->array);
 
    SCFree(ht);
}
 
int HashTableAdd(HashTable *ht, void *data, uint16_t datalen)
{
    if (ht == NULL || data == NULL)
        return -1;
 
    uint32_t hash = ht->Hash(ht, data, datalen);
 
    HashTableBucket *hb = SCCalloc(1, sizeof(HashTableBucket));
    if (unlikely(hb == NULL))
        goto error;
    hb->data = data;
    hb->size = datalen;
    hb->next = NULL;
 
    if (hash >= ht->array_size) {
        SCLogWarning("attempt to insert element out of hash array\n");
        goto error;
    }
 
    if (ht->array[hash] == NULL) {
        ht->array[hash] = hb;
    } else {
        hb->next = ht->array[hash];
        ht->array[hash] = hb;
    }
 
#ifdef UNITTESTS
    ht->count++;
#endif
 
    return 0;
 
error:
    if (hb != NULL)
        SCFree(hb);
    return -1;
}
/**
 *  \brief Remove an item from the hash table
 *  \details This function will search for the item in the hash table and remove it if found
 *  \note If the Free function is set, it will be called for the data item being removed.
 *  \param ht Pointer to the HashTable
 *  \param data Pointer to the data to remove
 *  \param datalen Length of the data to remove
 *  \return int 0 on success, -1 if the item was not found or an error occurred
 */
int HashTableRemove(HashTable *ht, void *data, uint16_t datalen)
{
    uint32_t hash = ht->Hash(ht, data, datalen);
 
    HashTableBucket **hashbucket = &(ht->array[hash]);
    while (*hashbucket != NULL) {
        if (ht->Compare((*hashbucket)->data, (*hashbucket)->size, data, datalen)) {
            *hashbucket = HashTableBucketFree(ht, *hashbucket);
            return 0;
        }
        hashbucket = &((*hashbucket)->next);
    }
 
    return -1;
}
 
void *HashTableLookup(HashTable *ht, void *data, uint16_t datalen)
{
    uint32_t hash = 0;
 
    if (ht == NULL)
        return NULL;
 
    hash = ht->Hash(ht, data, datalen);
 
    if (hash >= ht->array_size) {
        SCLogWarning("attempt to access element out of hash array\n");
        return NULL;
    }
 
    if (ht->array[hash] == NULL)
        return NULL;
 
    HashTableBucket *hashbucket = ht->array[hash];
    do {
        if (ht->Compare(hashbucket->data, hashbucket->size, data, datalen) == 1)
            return hashbucket->data;
 
        hashbucket = hashbucket->next;
    } while (hashbucket != NULL);
 
    return NULL;
}
 
// CallbackFn is an iterator, first argument is the data, second is user auxilary data
void HashTableIterate(HashTable *ht, void (*CallbackFn)(void *, void *), void *aux)
{
    if (ht == NULL || CallbackFn == NULL)
        return;
 
    for (uint32_t i = 0; i < ht->array_size; i++) {
        HashTableBucket *hashbucket = ht->array[i];
        while (hashbucket != NULL) {
            CallbackFn(hashbucket->data, aux);
            hashbucket = hashbucket->next;
        }
    }
}
 
uint32_t HashTableGenericHash(HashTable *ht, void *data, uint16_t datalen)
{
     uint8_t *d = (uint8_t *)data;
     uint32_t i;
     uint32_t hash = 0;
 
     for (i = 0; i < datalen; i++) {
         if (i == 0)      hash += (((uint32_t)*d++));
         else if (i == 1) hash += (((uint32_t)*d++) * datalen);
         else             hash *= (((uint32_t)*d++) * i) + datalen + i;
     }
 
     hash *= datalen;
     hash %= ht->array_size;
     return hash;
}
 
char HashTableDefaultCompare(void *data1, uint16_t len1, void *data2, uint16_t len2)
{
    if (len1 != len2)
        return 0;
 
    if (SCMemcmp(data1,data2,len1) != 0)
        return 0;
 
    return 1;
}
 
/*
 * ONLY TESTS BELOW THIS COMMENT
 */
 
#ifdef UNITTESTS
static int HashTableTestInit01 (void)
{
    HashTable *ht = HashTableInit(1024, HashTableGenericHash, NULL, NULL);
    if (ht == NULL)
        return 0;
 
    HashTableFree(ht);
    return 1;
}
 
/* no hash function, so it should fail */
static int HashTableTestInit02 (void)
{
    HashTable *ht = HashTableInit(1024, NULL, NULL, NULL);
    if (ht == NULL)
        return 1;
 
    HashTableFree(ht);
    return 0;
}
 
static int HashTableTestInit03 (void)
{
    int result = 0;
    HashTable *ht = HashTableInit(1024, HashTableGenericHash, NULL, NULL);
    if (ht == NULL)
        return 0;
 
    if (ht->Hash == HashTableGenericHash)
        result = 1;
 
    HashTableFree(ht);
    return result;
}
 
static int HashTableTestInit04 (void)
{
    HashTable *ht = HashTableInit(0, HashTableGenericHash, NULL, NULL);
    if (ht == NULL)
        return 1;
 
    HashTableFree(ht);
    return 0;
}
 
static int HashTableTestInit05 (void)
{
    int result = 0;
    HashTable *ht = HashTableInit(1024, HashTableGenericHash, NULL, NULL);
    if (ht == NULL)
        return 0;
 
    if (ht->Compare == HashTableDefaultCompare)
        result = 1;
 
    HashTableFree(ht);
    return result;
}
 
static char HashTableDefaultCompareTest(void *data1, uint16_t len1, void *data2, uint16_t len2)
{
    if (len1 != len2)
        return 0;
 
    if (SCMemcmp(data1,data2,len1) != 0)
        return 0;
 
    return 1;
}
 
static int HashTableTestInit06 (void)
{
    int result = 0;
    HashTable *ht = HashTableInit(1024, HashTableGenericHash, HashTableDefaultCompareTest, NULL);
    if (ht == NULL)
        return 0;
 
    if (ht->Compare == HashTableDefaultCompareTest)
        result = 1;
 
    HashTableFree(ht);
    return result;
}
 
static int HashTableTestAdd01 (void)
{
    int result = 0;
    HashTable *ht = HashTableInit(32, HashTableGenericHash, NULL, NULL);
    if (ht == NULL)
        goto end;
 
    int r = HashTableAdd(ht, (char *)"test", 0);
    if (r != 0)
        goto end;
 
    /* all is good! */
    result = 1;
end:
    if (ht != NULL) HashTableFree(ht);
    return result;
}
 
static int HashTableTestAdd02 (void)
{
    int result = 0;
    HashTable *ht = HashTableInit(32, HashTableGenericHash, NULL, NULL);
    if (ht == NULL)
        goto end;
 
    int r = HashTableAdd(ht, NULL, 4);
    if (r == 0)
        goto end;
 
    /* all is good! */
    result = 1;
end:
    if (ht != NULL) HashTableFree(ht);
    return result;
}
 
static int HashTableTestFull01 (void)
{
    int result = 0;
    HashTable *ht = HashTableInit(32, HashTableGenericHash, NULL, NULL);
    if (ht == NULL)
        goto end;
 
    int r = HashTableAdd(ht, (char *)"test", 4);
    if (r != 0)
        goto end;
 
    char *rp = HashTableLookup(ht, (char *)"test", 4);
    if (rp == NULL)
        goto end;
 
    r = HashTableRemove(ht, (char *)"test", 4);
    if (r != 0)
        goto end;
 
    /* all is good! */
    result = 1;
end:
    if (ht != NULL) HashTableFree(ht);
    return result;
}
 
static int HashTableTestFull02 (void)
{
    int result = 0;
    HashTable *ht = HashTableInit(32, HashTableGenericHash, NULL, NULL);
    if (ht == NULL)
        goto end;
 
    int r = HashTableAdd(ht, (char *)"test", 4);
    if (r != 0)
        goto end;
 
    char *rp = HashTableLookup(ht, (char *)"test", 4);
    if (rp == NULL)
        goto end;
 
    r = HashTableRemove(ht, (char *)"test2", 5);
    if (r == 0)
        goto end;
 
    /* all is good! */
    result = 1;
end:
    if (ht != NULL) HashTableFree(ht);
    return result;
}
 
static int HashTableTestCollisionBug(void)
{
    HashTable *ht = HashTableInit(32, HashTableGenericHash, NULL, NULL);
    FAIL_IF_NULL(ht);
 
    FAIL_IF_NOT(HashTableGenericHash(ht, (void *)"abc", 3) ==
                HashTableGenericHash(ht, (void *)"iln", 3));
 
    // Add two strings that collide in the same bucket
    FAIL_IF_NOT(HashTableAdd(ht, (char *)"abc", 3) == 0);
    FAIL_IF_NOT(HashTableAdd(ht, (char *)"iln", 3) == 0);
 
    // Verify both keys are present
    FAIL_IF_NULL(HashTableLookup(ht, (char *)"abc", 3));
    FAIL_IF_NULL(HashTableLookup(ht, (char *)"iln", 3));
 
    // Remove first key once
    FAIL_IF_NOT(HashTableRemove(ht, (char *)"abc", 3) == 0);
 
    // Verify first key is gone, second key remains
    FAIL_IF_NOT_NULL(HashTableLookup(ht, (char *)"abc", 3));
    FAIL_IF_NULL(HashTableLookup(ht, (char *)"iln", 3));
 
    // Remove first key again (should not affect "iln")
    FAIL_IF(HashTableRemove(ht, (char *)"abc", 3) == 0);
 
    // Verify second key is still present (correct behavior)
    FAIL_IF_NULL(HashTableLookup(ht, (char *)"iln", 3));
 
    HashTableFree(ht);
    PASS;
}
#endif
 
void HashTableRegisterTests(void)
{
#ifdef UNITTESTS
    UtRegisterTest("HashTableTestInit01", HashTableTestInit01);
    UtRegisterTest("HashTableTestInit02", HashTableTestInit02);
    UtRegisterTest("HashTableTestInit03", HashTableTestInit03);
    UtRegisterTest("HashTableTestInit04", HashTableTestInit04);
    UtRegisterTest("HashTableTestInit05", HashTableTestInit05);
    UtRegisterTest("HashTableTestInit06", HashTableTestInit06);
 
    UtRegisterTest("HashTableTestAdd01", HashTableTestAdd01);
    UtRegisterTest("HashTableTestAdd02", HashTableTestAdd02);
 
    UtRegisterTest("HashTableTestFull01", HashTableTestFull01);
    UtRegisterTest("HashTableTestFull02", HashTableTestFull02);
    UtRegisterTest("HashTableTestCollisionBug", HashTableTestCollisionBug);
#endif
}