Example #1
0
/******************************************************************************
       Name : HashInsert()
Description : Function to insert new record into the hash table.
 Parameters : htable  - address (void *) of hashtable header
            : record  - address (void *) of record to insert
            : recsize - size of record (bytes)
    Returns : 
   Comments : This routine takes a copy of the user record.
            : New record placed in front of any existing equal hash record.
 ******************************************************************************/
void
HashInsert(HASHTABLE htable, void *record, int recsize)
{
    HTAB *h = (HTAB *) htable;
    int  hash = h->hash(record) % h->numentries;
    BHDR *newbhdr = malloc(sizeof(BHDR));
    void *newrec = malloc(recsize);

    if (newbhdr == NULL || newrec == NULL)
        error("Out of memory");

    memcpy(newrec, record, recsize);

    newbhdr->data = newrec;
    newbhdr->next = h->table[hash];
    h->table[hash] = newbhdr;
}
Example #2
0
/******************************************************************************
       Name : HashLookup()
Description : Look for a record in a hashtable.
 Parameters : htable - hashtable to look in
            : record - the record to look for
    Returns : Returns found data or NULL if not found.
   Comments : 
 ******************************************************************************/
void *
HashLookup(HASHTABLE htable, void *record)
{
    void *result = NULL;
    HTAB *h = (HTAB *) htable;
    int  hash = h->hash(record) % h->numentries;
    BHDR *bptr;

    bptr = h->table[hash];

    while (bptr != NULL)
    {
        if (h->compare(record, bptr->data) == 0)
        {
            result = bptr->data;
            break;
        }

        bptr = bptr->next;
    }

    return result;
}
Example #3
0
/* ARGSUSED */
DB *
__hash_open(const char *file, int flags, int mode,
    const HASHINFO *info,	/* Special directives for create */
    int dflags)
{
	HTAB *hashp;
	struct stat statbuf;
	DB *dbp;
	int bpages, hdrsize, new_table, nsegs, save_errno;

	if ((flags & O_ACCMODE) == O_WRONLY) {
		errno = EINVAL;
		return (NULL);
	}

	if (!(hashp = (HTAB *)calloc(1, sizeof(HTAB))))
		return (NULL);
	hashp->fp = -1;

	/*
	 * Even if user wants write only, we need to be able to read
	 * the actual file, so we need to open it read/write. But, the
	 * field in the hashp structure needs to be accurate so that
	 * we can check accesses.
	 */
	hashp->flags = flags;

	if (file) {
		if ((hashp->fp = _open(file, flags | O_CLOEXEC, mode)) == -1)
			RETURN_ERROR(errno, error0);
		new_table = _fstat(hashp->fp, &statbuf) == 0 &&
		    statbuf.st_size == 0 && (flags & O_ACCMODE) != O_RDONLY;
	} else
		new_table = 1;

	if (new_table) {
		if (!(hashp = init_hash(hashp, file, info)))
			RETURN_ERROR(errno, error1);
	} else {
		/* Table already exists */
		if (info && info->hash)
			hashp->hash = info->hash;
		else
			hashp->hash = __default_hash;

		hdrsize = _read(hashp->fp, &hashp->hdr, sizeof(HASHHDR));
#if BYTE_ORDER == LITTLE_ENDIAN
		swap_header(hashp);
#endif
		if (hdrsize == -1)
			RETURN_ERROR(errno, error1);
		if (hdrsize != sizeof(HASHHDR))
			RETURN_ERROR(EFTYPE, error1);
		/* Verify file type, versions and hash function */
		if (hashp->MAGIC != HASHMAGIC)
			RETURN_ERROR(EFTYPE, error1);
#define	OLDHASHVERSION	1
		if (hashp->VERSION != HASHVERSION &&
		    hashp->VERSION != OLDHASHVERSION)
			RETURN_ERROR(EFTYPE, error1);
		if ((int32_t)hashp->hash(CHARKEY, sizeof(CHARKEY)) != hashp->H_CHARKEY)
			RETURN_ERROR(EFTYPE, error1);
		/*
		 * Figure out how many segments we need.  Max_Bucket is the
		 * maximum bucket number, so the number of buckets is
		 * max_bucket + 1.
		 */
		nsegs = (hashp->MAX_BUCKET + 1 + hashp->SGSIZE - 1) /
			 hashp->SGSIZE;
		if (alloc_segs(hashp, nsegs))
			/*
			 * If alloc_segs fails, table will have been destroyed
			 * and errno will have been set.
			 */
			return (NULL);
		/* Read in bitmaps */
		bpages = (hashp->SPARES[hashp->OVFL_POINT] +
		    (hashp->BSIZE << BYTE_SHIFT) - 1) >>
		    (hashp->BSHIFT + BYTE_SHIFT);

		hashp->nmaps = bpages;
		(void)memset(&hashp->mapp[0], 0, bpages * sizeof(u_int32_t *));
	}

	/* Initialize Buffer Manager */
	if (info && info->cachesize)
		__buf_init(hashp, info->cachesize);
	else
		__buf_init(hashp, DEF_BUFSIZE);

	hashp->new_file = new_table;
	hashp->save_file = file && (hashp->flags & O_RDWR);
	hashp->cbucket = -1;
	if (!(dbp = (DB *)malloc(sizeof(DB)))) {
		save_errno = errno;
		hdestroy(hashp);
		errno = save_errno;
		return (NULL);
	}
	dbp->internal = hashp;
	dbp->close = hash_close;
	dbp->del = hash_delete;
	dbp->fd = hash_fd;
	dbp->get = hash_get;
	dbp->put = hash_put;
	dbp->seq = hash_seq;
	dbp->sync = hash_sync;
	dbp->type = DB_HASH;

#ifdef DEBUG
	(void)fprintf(stderr,
"%s\n%s%p\n%s%d\n%s%d\n%s%d\n%s%d\n%s%d\n%s%d\n%s%d\n%s%d\n%s%d\n%s%x\n%s%x\n%s%d\n%s%d\n",
	    "init_htab:",
	    "TABLE POINTER   ", hashp,
	    "BUCKET SIZE     ", hashp->BSIZE,
	    "BUCKET SHIFT    ", hashp->BSHIFT,
	    "DIRECTORY SIZE  ", hashp->DSIZE,
	    "SEGMENT SIZE    ", hashp->SGSIZE,
	    "SEGMENT SHIFT   ", hashp->SSHIFT,
	    "FILL FACTOR     ", hashp->FFACTOR,
	    "MAX BUCKET      ", hashp->MAX_BUCKET,
	    "OVFL POINT	     ", hashp->OVFL_POINT,
	    "LAST FREED      ", hashp->LAST_FREED,
	    "HIGH MASK       ", hashp->HIGH_MASK,
	    "LOW  MASK       ", hashp->LOW_MASK,
	    "NSEGS           ", hashp->nsegs,
	    "NKEYS           ", hashp->NKEYS);
#endif
#ifdef HASH_STATISTICS
	hash_overflows = hash_accesses = hash_collisions = hash_expansions = 0;
#endif
	return (dbp);

error1:
	if (hashp != NULL)
		(void)_close(hashp->fp);

error0:
	free(hashp);
	errno = save_errno;
	return (NULL);
}