/******************************************************************************
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;
}
/******************************************************************************
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;
}
/* 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);
}
