/*-

 * Copyright (c) 1990, 1993, 1994

 *	The Regents of the University of California.  All rights reserved.

 *

 * This code is derived from software contributed to Berkeley by

 * Margo Seltzer.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 * 3. All advertising materials mentioning features or use of this software

 *    must display the following acknowledgement:

 *	This product includes software developed by the University of

 *	California, Berkeley and its contributors.

 * 4. Neither the name of the University nor the names of its contributors

 *    may be used to endorse or promote products derived from this software

 *    without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND

 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE

 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS

 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT

 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY

 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF

 * SUCH DAMAGE.

 */

#if defined(LIBC_SCCS) && !defined(lint)

static char sccsid[] = "@(#)hash.c	8.12 (Berkeley) 11/7/95";

#endif /* LIBC_SCCS and not lint */

#include <sys/param.h>

#include <sys/stat.h>

#include <errno.h>

#include <fcntl.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <unistd.h>

#ifdef DEBUG

#include <assert.h>

#endif

#include "k5-int.h"

#include "db-int.h"

#include "hash.h"

#include "page.h"

#include "extern.h"

static int32_t flush_meta __P((HTAB *));

static int32_t hash_access __P((HTAB *, ACTION, const DBT *, DBT *));

static int32_t hash_close __P((DB *));

static int32_t hash_delete __P((const DB *, const DBT *, u_int32_t));

static int32_t hash_fd __P((const DB *));

static int32_t hash_get __P((const DB *, const DBT *, DBT *, u_int32_t));

static int32_t hash_put __P((const DB *, DBT *, const DBT *, u_int32_t));

static int32_t hash_seq __P((const DB *, DBT *, DBT *, u_int32_t));

static int32_t hash_sync __P((const DB *, u_int32_t));

static int32_t hdestroy __P((HTAB *));

static int32_t cursor_get __P((const DB *, CURSOR *, DBT *, DBT *, \

	u_int32_t));

static int32_t cursor_delete __P((const DB *, CURSOR *, u_int32_t));

static HTAB *init_hash __P((HTAB *, const char *, const HASHINFO *));

static int32_t init_htab __P((HTAB *, int32_t));

#if DB_BYTE_ORDER == DB_LITTLE_ENDIAN

static void swap_header __P((HTAB *));

static void swap_header_copy __P((HASHHDR *, HASHHDR *));

#endif

static u_int32_t hget_header __P((HTAB *, u_int32_t));

static void hput_header __P((HTAB *));

#define RETURN_ERROR(ERR, LOC)	{ save_errno = ERR; goto LOC; }

/* Return values */

#define	SUCCESS	 (0)

#define	ERROR	(-1)

#define	ABNORMAL (1)

#ifdef HASH_STATISTICS

u_int32_t hash_accesses, hash_collisions, hash_expansions, hash_overflows,

	hash_bigpages;

#endif

/************************** INTERFACE ROUTINES ***************************/

/* OPEN/CLOSE */

extern DB *

__kdb2_hash_open(file, flags, mode, info, dflags)

	const char *file;

	int flags, mode, dflags;

	const HASHINFO *info;	/* Special directives for create */

{

	struct stat statbuf;

	DB *dbp;

	DBT mpool_key;

	HTAB *hashp;

	int32_t bpages, csize, new_table, save_errno;

	if (!file || (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;

	hashp->save_file = hashp->flags & O_RDWR;

	new_table = 0;

	if (!file || (flags & O_TRUNC) ||

	    (stat(file, &statbuf) && (errno == ENOENT))) {

		if (errno == ENOENT)

			errno = 0;	/* In case someone looks at errno. */

		new_table = 1;

	}

	if (file) {

		if ((hashp->fp = THREEPARAMOPEN(file, flags|O_BINARY, mode)) == -1)

			RETURN_ERROR(errno, error0);

		(void)fcntl(hashp->fp, F_SETFD, 1);

	}

	/* Process arguments to set up hash table header. */

	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;

		/* copy metadata from page into header */

		if (hget_header(hashp,

		    (info && info->bsize ? info->bsize : DEF_BUCKET_SIZE)) !=

		    sizeof(HASHHDR))

			RETURN_ERROR(EFTYPE, error1);

		/* Verify file type, versions and hash function */

		if (hashp->hdr.magic != HASHMAGIC)

			RETURN_ERROR(EFTYPE, error1);

#define	OLDHASHVERSION	1

		if (hashp->hdr.version != HASHVERSION &&

		    hashp->hdr.version != OLDHASHVERSION)

			RETURN_ERROR(EFTYPE, error1);

		if (hashp->hash(CHARKEY, sizeof(CHARKEY))

		    != hashp->hdr.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.

		 */

		/* Read in bitmaps */

		bpages = (hashp->hdr.spares[hashp->hdr.ovfl_point] +

		    (hashp->hdr.bsize << BYTE_SHIFT) - 1) >>

		    (hashp->hdr.bshift + BYTE_SHIFT);

		hashp->nmaps = bpages;

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

	}

	/* start up mpool */

	mpool_key.data = (u_int8_t *)file;

	mpool_key.size = strlen(file);

	if (info && info->cachesize)

		csize = info->cachesize / hashp->hdr.bsize;

	else

		csize = DEF_CACHESIZE / hashp->hdr.bsize;

	hashp->mp = mpool_open(&mpool_key, hashp->fp, hashp->hdr.bsize, csize);

	if (!hashp->mp)

		RETURN_ERROR(errno, error1);

	mpool_filter(hashp->mp, __pgin_routine, __pgout_routine, hashp);

	/*

	 * For a new table, set up the bitmaps.

	 */

	if (new_table &&

	   init_htab(hashp, info && info->nelem ? info->nelem : 1))

		goto error2;

	/* initialize the cursor queue */

	TAILQ_INIT(&hashp->curs_queue);

	hashp->seq_cursor = NULL;

	/* get a chunk of memory for our split buffer */

	hashp->split_buf = (PAGE16 *)malloc(hashp->hdr.bsize);

	if (!hashp->split_buf)

		goto error2;

	hashp->new_file = new_table;

	if (!(dbp = (DB *)malloc(sizeof(DB))))

		goto error2;

	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%lx\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   ", (void *)hashp,

	    "BUCKET SIZE     ", hashp->hdr.bsize,

	    "BUCKET SHIFT    ", hashp->hdr.bshift,

	    "FILL FACTOR     ", hashp->hdr.ffactor,

	    "MAX BUCKET      ", hashp->hdr.max_bucket,

	    "OVFL POINT      ", hashp->hdr.ovfl_point,

	    "LAST FREED      ", hashp->hdr.last_freed,

	    "HIGH MASK       ", hashp->hdr.high_mask,

	    "LOW  MASK       ", hashp->hdr.low_mask,

	    "NKEYS           ", hashp->hdr.nkeys);

#endif

#ifdef HASH_STATISTICS

	hash_overflows = hash_accesses = hash_collisions = hash_expansions = 0;

	hash_bigpages = 0;

#endif

	return (dbp);

error2:

	save_errno = errno;

	hdestroy(hashp);

	errno = save_errno;

	return (NULL);

error1:

	if (hashp != NULL)

		(void)close(hashp->fp);

error0:

	free(hashp);

	errno = save_errno;

	return (NULL);

}

static int32_t

hash_close(dbp)

	DB *dbp;

{

	HTAB *hashp;

	int32_t retval;

	if (!dbp)

		return (ERROR);

	hashp = (HTAB *)dbp->internal;

	retval = hdestroy(hashp);

	free(dbp);

	return (retval);

}

static int32_t

hash_fd(dbp)

	const DB *dbp;

{

	HTAB *hashp;

	if (!dbp)

		return (ERROR);

	hashp = (HTAB *)dbp->internal;

	if (hashp->fp == -1) {

		errno = ENOENT;

		return (-1);

	}

	return (hashp->fp);

}

/************************** LOCAL CREATION ROUTINES **********************/

static HTAB *

init_hash(hashp, file, info)

	HTAB *hashp;

	const char *file;

	const HASHINFO *info;

{

	struct stat statbuf;

	hashp->hdr.nkeys = 0;

	hashp->hdr.lorder = DB_BYTE_ORDER;

	hashp->hdr.bsize = DEF_BUCKET_SIZE;

	hashp->hdr.bshift = DEF_BUCKET_SHIFT;

	hashp->hdr.ffactor = DEF_FFACTOR;

	hashp->hash = __default_hash;

	memset(hashp->hdr.spares, 0, sizeof(hashp->hdr.spares));

	memset(hashp->hdr.bitmaps, 0, sizeof(hashp->hdr.bitmaps));

	/* Fix bucket size to be optimal for file system */

	if (file != NULL) {

		if (stat(file, &statbuf))

			return (NULL);

		hashp->hdr.bsize = statbuf.st_blksize;

		if (hashp->hdr.bsize > MAX_BSIZE)

		    hashp->hdr.bsize = MAX_BSIZE;

		hashp->hdr.bshift = __log2(hashp->hdr.bsize);

	}

	if (info) {

		if (info->bsize) {

			/* Round pagesize up to power of 2 */

			hashp->hdr.bshift = __log2(info->bsize);

			hashp->hdr.bsize = 1 << hashp->hdr.bshift;

			if (hashp->hdr.bsize > MAX_BSIZE) {

				errno = EINVAL;

				return (NULL);

			}

		}

		if (info->ffactor)

			hashp->hdr.ffactor = info->ffactor;

		if (info->hash)

			hashp->hash = info->hash;

		if (info->lorder) {

			if ((info->lorder != DB_BIG_ENDIAN) &&

			    (info->lorder != DB_LITTLE_ENDIAN)) {

				errno = EINVAL;

				return (NULL);

			}

			hashp->hdr.lorder = info->lorder;

		}

	}

	return (hashp);

}

/*

 * Returns 0 on No Error

 */

static int32_t

init_htab(hashp, nelem)

	HTAB *hashp;

	int32_t nelem;

{

	int32_t l2, nbuckets;

	/*

	 * Divide number of elements by the fill factor and determine a

	 * desired number of buckets.  Allocate space for the next greater

	 * power of two number of buckets.

	 */

	nelem = (nelem - 1) / hashp->hdr.ffactor + 1;

	l2 = __log2(MAX(nelem, 2));

	nbuckets = 1 << l2;

	hashp->hdr.spares[l2] = l2 + 1;

	hashp->hdr.spares[l2 + 1] = l2 + 1;

	hashp->hdr.ovfl_point = l2;

	hashp->hdr.last_freed = 2;

	hashp->hdr.max_bucket = hashp->hdr.low_mask = nbuckets - 1;

	hashp->hdr.high_mask = (nbuckets << 1) - 1;

	/*

	 * The number of header pages is the size of the header divided by

	 * the amount of freespace on header pages (the page size - the

	 * size of 1 integer where the length of the header info on that

	 * page is stored) plus another page if it didn't divide evenly.

	 */

	hashp->hdr.hdrpages =

	    (sizeof(HASHHDR) / (hashp->hdr.bsize - HEADER_OVERHEAD)) +

	    (((sizeof(HASHHDR) % (hashp->hdr.bsize - HEADER_OVERHEAD)) == 0)

	    ? 0 : 1);

	/* Create pages for these buckets */

	/*

	for (i = 0; i <= hashp->hdr.max_bucket; i++) {

		if (__new_page(hashp, (u_int32_t)i, A_BUCKET) != 0)

			return (-1);

	}

	*/

	/* First bitmap page is at: splitpoint l2 page offset 1 */

	if (__ibitmap(hashp, OADDR_OF(l2, 1), l2 + 1, 0))

		return (-1);

	return (0);

}

/*

 * Functions to get/put hash header.  We access the file directly.

 */

static u_int32_t

hget_header(hashp, page_size)

	HTAB *hashp;

	u_int32_t page_size;

{

	u_int32_t num_copied;

	u_int8_t *hdr_dest;

	num_copied = 0;

	hdr_dest = (u_int8_t *)&hashp->hdr;

	/*

	 * XXX

	 * This should not be printing to stderr on a "normal" error case.

	 */

	lseek(hashp->fp, 0, SEEK_SET);

	num_copied = read(hashp->fp, hdr_dest, sizeof(HASHHDR));

	if (num_copied != sizeof(HASHHDR)) {

		fprintf(stderr, "hash: could not retrieve header");

		return (0);

	}

#if DB_BYTE_ORDER == DB_LITTLE_ENDIAN

	swap_header(hashp);

#endif

	return (num_copied);

}

static void

hput_header(hashp)

	HTAB *hashp;

{

	HASHHDR *whdrp;

#if DB_BYTE_ORDER == DB_LITTLE_ENDIAN

	HASHHDR whdr;

#endif

	u_int32_t num_copied;

	num_copied = 0;

	whdrp = &hashp->hdr;

#if DB_BYTE_ORDER == DB_LITTLE_ENDIAN

	whdrp = &whdr;

	swap_header_copy(&hashp->hdr, whdrp);

#endif

	lseek(hashp->fp, 0, SEEK_SET);

	num_copied = write(hashp->fp, whdrp, sizeof(HASHHDR));

	if (num_copied != sizeof(HASHHDR))

		(void)fprintf(stderr, "hash: could not write hash header");

	return;

}

/********************** DESTROY/CLOSE ROUTINES ************************/

/*

 * Flushes any changes to the file if necessary and destroys the hashp

 * structure, freeing all allocated space.

 */

static int32_t

hdestroy(hashp)

	HTAB *hashp;

{

	int32_t save_errno;

	save_errno = 0;

#ifdef HASH_STATISTICS

	{ int i;

	(void)fprintf(stderr, "hdestroy: accesses %ld collisions %ld\n",

	    hash_accesses, hash_collisions);

	(void)fprintf(stderr,

	    "hdestroy: expansions %ld\n", hash_expansions);

	(void)fprintf(stderr,

	    "hdestroy: overflows %ld\n", hash_overflows);

	(void)fprintf(stderr,

	    "hdestroy: big key/data pages %ld\n", hash_bigpages);

	(void)fprintf(stderr,

	    "keys %ld maxp %d\n", hashp->hdr.nkeys, hashp->hdr.max_bucket);

	for (i = 0; i < NCACHED; i++)

		(void)fprintf(stderr,

		    "spares[%d] = %d\n", i, hashp->hdr.spares[i]);

	}

#endif

	if (flush_meta(hashp) && !save_errno)

		save_errno = errno;

	/* Free the split page */

	if (hashp->split_buf)

		free(hashp->split_buf);

	/* Free the big key and big data returns */

	if (hashp->bigkey_buf)

		free(hashp->bigkey_buf);

	if (hashp->bigdata_buf)

		free(hashp->bigdata_buf);

	/* XXX This should really iterate over the cursor queue, but

	   it's not clear how to do that, and the only cursor a hash

	   table ever creates is the one used by hash_seq().  Passing

	   NULL as the first arg is also a kludge, but I know that

	   it's never used, so I do it.  The intent is to plug the

	   memory leak.  Correctness can come later. */

	if (hashp->seq_cursor)

		hashp->seq_cursor->delete(NULL, hashp->seq_cursor, 0);

	/* shut down mpool */

	mpool_sync(hashp->mp);

	mpool_close(hashp->mp);

	if (hashp->fp != -1)

		(void)close(hashp->fp);

	/*

	 * *** This may cause problems if hashp->fname is set in any case

	 * other than the case that we are generating a temporary file name.

	 * Note that the new version of mpool should support temporary

	 * files within mpool itself.

	 */

	if (hashp->fname && !hashp->save_file) {

#ifdef DEBUG

		fprintf(stderr, "Unlinking file %s.\n", hashp->fname);

#endif

		/* we need to chmod the file to allow it to be deleted... */

		chmod(hashp->fname, 0700);

		unlink(hashp->fname);

	}

	free(hashp);

	if (save_errno) {

		errno = save_errno;

		return (ERROR);

	}

	return (SUCCESS);

}

/*

 * Write modified pages to disk

 *

 * Returns:

 *	 0 == OK

 *	-1 ERROR

 */

static int32_t

hash_sync(dbp, flags)

	const DB *dbp;

	u_int32_t flags;

{

	HTAB *hashp;

	hashp = (HTAB *)dbp->internal;

	/*

	 * XXX

	 * Check success/failure conditions.

	 */

	return (flush_meta(hashp) || mpool_sync(hashp->mp));

}

/*

 * Returns:

 *	 0 == OK

 *	-1 indicates that errno should be set

 */

static int32_t

flush_meta(hashp)

	HTAB *hashp;

{

	int32_t i;

	if (!hashp->save_file)

		return (0);

	hashp->hdr.magic = HASHMAGIC;

	hashp->hdr.version = HASHVERSION;

	hashp->hdr.h_charkey = hashp->hash(CHARKEY, sizeof(CHARKEY));

	/* write out metadata */

	hput_header(hashp);

	for (i = 0; i < NCACHED; i++)

		if (hashp->mapp[i]) {

			if (__put_page(hashp,

			    (PAGE16 *)hashp->mapp[i], A_BITMAP, 1))

				return (-1);

			hashp->mapp[i] = NULL;

		}

	return (0);

}

/*******************************SEARCH ROUTINES *****************************/

/*

 * All the access routines return

 *

 * Returns:

 *	 0 on SUCCESS

 *	 1 to indicate an external ERROR (i.e. key not found, etc)

 *	-1 to indicate an internal ERROR (i.e. out of memory, etc)

 */

/* *** make sure this is true! */

static int32_t

hash_get(dbp, key, data, flag)

	const DB *dbp;

	const DBT *key;

	DBT *data;

	u_int32_t flag;

{

	HTAB *hashp;

	hashp = (HTAB *)dbp->internal;

	if (flag) {

		hashp->local_errno = errno = EINVAL;

		return (ERROR);

	}

	return (hash_access(hashp, HASH_GET, key, data));

}

static int32_t

hash_put(dbp, key, data, flag)

	const DB *dbp;

	DBT *key;

	const DBT *data;

	u_int32_t flag;

{

	HTAB *hashp;

	hashp = (HTAB *)dbp->internal;

	if (flag && flag != R_NOOVERWRITE) {

		hashp->local_errno = errno = EINVAL;

		return (ERROR);

	}

	if ((hashp->flags & O_ACCMODE) == O_RDONLY) {

		hashp->local_errno = errno = EPERM;

		return (ERROR);

	}

	return (hash_access(hashp, flag == R_NOOVERWRITE ?

		HASH_PUTNEW : HASH_PUT, key, (DBT *)data));

}

static int32_t

hash_delete(dbp, key, flag)

	const DB *dbp;

	const DBT *key;

	u_int32_t flag;		/* Ignored */

{

	HTAB *hashp;

	hashp = (HTAB *)dbp->internal;

	if (flag) {

		hashp->local_errno = errno = EINVAL;

		return (ERROR);

	}

	if ((hashp->flags & O_ACCMODE) == O_RDONLY) {

		hashp->local_errno = errno = EPERM;

		return (ERROR);

	}

	return (hash_access(hashp, HASH_DELETE, key, NULL));

}

/*

 * Assume that hashp has been set in wrapper routine.

 */

static int32_t

hash_access(hashp, action, key, val)

	HTAB *hashp;

	ACTION action;

	const DBT *key;

	DBT *val;

{

	DBT page_key, page_val;

	CURSOR cursor;

	ITEM_INFO item_info;

	u_int32_t bucket;

	u_int32_t num_items;

#ifdef HASH_STATISTICS

	hash_accesses++;

#endif

	num_items = 0;

	/*

	 * Set up item_info so that we're looking for space to add an item

	 * as we cycle through the pages looking for the key.

	 */

	if (action == HASH_PUT || action == HASH_PUTNEW) {

		if (ISBIG(key->size + val->size, hashp))

			item_info.seek_size = PAIR_OVERHEAD;

		else

			item_info.seek_size = key->size + val->size;

	} else

		item_info.seek_size = 0;

	item_info.seek_found_page = 0;

	bucket = __call_hash(hashp, (int8_t *)key->data, key->size);

	cursor.pagep = NULL;

	__get_item_reset(hashp, &cursor);

	cursor.bucket = bucket;

	while (1) {

		__get_item_next(hashp, &cursor, &page_key, &page_val, &item_info);

		if (item_info.status == ITEM_ERROR)

			return (ABNORMAL);

		if (item_info.status == ITEM_NO_MORE)

			break;

		num_items++;

		if (item_info.key_off == BIGPAIR) {

			/*

			 * !!!

			 * 0 is a valid index.

			 */

			if (__find_bigpair(hashp, &cursor, (int8_t *)key->data,

			    key->size) > 0)

				goto found;

		} else if (key->size == page_key.size &&

		    !memcmp(key->data, page_key.data, key->size))

			goto found;

	}

#ifdef HASH_STATISTICS

	hash_collisions++;

#endif

	__get_item_done(hashp, &cursor);

	/*

	 * At this point, item_info will list either the last page in

	 * the chain, or the last page in the chain plus a pgno for where

	 * to find the first page in the chain with space for the

	 * item we wish to add.

	 */

	/* Not found */

	switch (action) {

	case HASH_PUT:

	case HASH_PUTNEW:

		if (__addel(hashp, &item_info, key, val, num_items, 0))

			return (ERROR);

		break;

	case HASH_GET:

	case HASH_DELETE:

	default:

		return (ABNORMAL);

	}

	if (item_info.caused_expand)

		__expand_table(hashp);

	return (SUCCESS);

found:	__get_item_done(hashp, &cursor);

	switch (action) {

	case HASH_PUTNEW:

		/* mpool_put(hashp->mp, pagep, 0); */

		return (ABNORMAL);

	case HASH_GET:

		if (item_info.key_off == BIGPAIR) {

			if (__big_return(hashp, &item_info, val, 0))

				return (ERROR);

		} else {

			val->data = page_val.data;

			val->size = page_val.size;

		}

		/* *** data may not be available! */

		break;

	case HASH_PUT:

		if (__delpair(hashp, &cursor, &item_info) ||

		    __addel(hashp, &item_info, key, val, UNKNOWN, 0))

			return (ERROR);

		__get_item_done(hashp, &cursor);

		if (item_info.caused_expand)

			__expand_table(hashp);

		break;

	case HASH_DELETE:

		if (__delpair(hashp, &cursor, &item_info))

			return (ERROR);

		break;

	default:

		abort();

	}

	return (SUCCESS);

}

/* ****************** CURSORS ********************************** */

CURSOR *

__cursor_creat(dbp)

	const DB *dbp;

{

	CURSOR *new_curs;

	HTAB *hashp;

	new_curs = (CURSOR *)malloc(sizeof(struct cursor_t));

	if (!new_curs)

		return NULL;

	new_curs->internal =

	    (struct item_info *)malloc(sizeof(struct item_info));

	if (!new_curs->internal) {

		free(new_curs);

		return NULL;

	}

	new_curs->get = cursor_get;

	new_curs->delete = cursor_delete;

	new_curs->bucket = 0;

	new_curs->pgno = INVALID_PGNO;

	new_curs->ndx = 0;

	new_curs->pgndx = 0;

	new_curs->pagep = NULL;

	/* place onto queue of cursors */

	hashp = (HTAB *)dbp->internal;

	TAILQ_INSERT_TAIL(&hashp->curs_queue, new_curs, queue);

	return new_curs;

}

static int32_t

cursor_get(dbp, cursorp, key, val, flags)

	const DB *dbp;

	CURSOR *cursorp;

	DBT *key, *val;

	u_int32_t flags;

{

	HTAB *hashp;

	ITEM_INFO item_info;

	hashp = (HTAB *)dbp->internal;

	if (flags && flags != R_FIRST && flags != R_NEXT) {

		hashp->local_errno = errno = EINVAL;

		return (ERROR);

	}

#ifdef HASH_STATISTICS

	hash_accesses++;

#endif

	item_info.seek_size = 0;

	if (flags == R_FIRST)

		__get_item_first(hashp, cursorp, key, val, &item_info);

	else

		__get_item_next(hashp, cursorp, key, val, &item_info);

	/*

	 * This needs to be changed around.  As is, get_item_next advances

	 * the pointers on the page but this function actually advances

	 * bucket pointers.  This works, since the only other place we

	 * use get_item_next is in hash_access which only deals with one

	 * bucket at a time.  However, there is the problem that certain other

	 * functions (such as find_bigpair and delpair) depend on the

	 * pgndx member of the cursor.  Right now, they are using pngdx - 1

	 * since indices refer to the __next__ item that is to be fetched

	 * from the page.  This is ugly, as you may have noticed, whoever

	 * you are.  The best solution would be to depend on item_infos to

	 * deal with _current_ information, and have the cursors only

	 * deal with _next_ information.  In that scheme, get_item_next

	 * would also advance buckets.  Version 3...

	 */

	/*

	 * Must always enter this loop to do error handling and

	 * check for big key/data pair.

	 */

	while (1) {

		if (item_info.status == ITEM_OK) {

			if (item_info.key_off == BIGPAIR &&

			    __big_keydata(hashp, cursorp->pagep, key, val,

			    item_info.pgndx))