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GCC Code Coverage Report

Directory:	./		Exec	Total	Coverage
File:	lib/libc/db/hash/hash_bigkey.c	Lines:	0	277	0.0 %
Date:	2017-11-07	Branches:	0	140	0.0 %


/*	$OpenBSD: hash_bigkey.c,v 1.19 2015/12/28 22:08:18 mmcc Exp $	*/

/*-
 * 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. 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.
 */

/*
 * PACKAGE: hash
 * DESCRIPTION:
 *	Big key/data handling for the hashing package.
 *
 * ROUTINES:
 * External
 *	__big_keydata
 *	__big_split
 *	__big_insert
 *	__big_return
 *	__big_delete
 *	__find_last_page
 * Internal
 *	collect_key
 *	collect_data
 */

#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#ifdef DEBUG
#include <assert.h>
#endif

#include <db.h>
#include "hash.h"
#include "page.h"
#include "extern.h"

#define MINIMUM(a, b)	(((a) < (b)) ? (a) : (b))

static int collect_key(HTAB *, BUFHEAD *, int, DBT *, int);
static int collect_data(HTAB *, BUFHEAD *, int, int);

/*
 * Big_insert
 *
 * You need to do an insert and the key/data pair is too big
 *
 * Returns:
 * 0 ==> OK
 *-1 ==> ERROR
 */
int
__big_insert(HTAB *hashp, BUFHEAD *bufp, const DBT *key, const DBT *val)
{
	u_int16_t *p;
	int key_size, n, val_size;
	u_int16_t space, move_bytes, off;
	char *cp, *key_data, *val_data;

	cp = bufp->page;		/* Character pointer of p. */
	p = (u_int16_t *)cp;

	key_data = (char *)key->data;
	key_size = key->size;
	val_data = (char *)val->data;
	val_size = val->size;

	/* First move the Key */
	for (space = FREESPACE(p) - BIGOVERHEAD; key_size;
	    space = FREESPACE(p) - BIGOVERHEAD) {
		move_bytes = MINIMUM(space, key_size);
		off = OFFSET(p) - move_bytes;
		memmove(cp + off, key_data, move_bytes);
		key_size -= move_bytes;
		key_data += move_bytes;
		n = p[0];
		p[++n] = off;
		p[0] = ++n;
		FREESPACE(p) = off - PAGE_META(n);
		OFFSET(p) = off;
		p[n] = PARTIAL_KEY;
		bufp = __add_ovflpage(hashp, bufp);
		if (!bufp)
			return (-1);
		n = p[0];
		if (!key_size) {
			space = FREESPACE(p);
			if (space) {
				move_bytes = MINIMUM(space, val_size);
				/*
				 * If the data would fit exactly in the
				 * remaining space, we must overflow it to the
				 * next page; otherwise the invariant that the
				 * data must end on a page with FREESPACE
				 * non-zero would fail.
				 */
				if (space == val_size && val_size == val->size)
					goto toolarge;
				off = OFFSET(p) - move_bytes;
				memmove(cp + off, val_data, move_bytes);
				val_data += move_bytes;
				val_size -= move_bytes;
				p[n] = off;
				p[n - 2] = FULL_KEY_DATA;
				FREESPACE(p) = FREESPACE(p) - move_bytes;
				OFFSET(p) = off;
			} else {
			toolarge:
				p[n - 2] = FULL_KEY;
			}
		}
		p = (u_int16_t *)bufp->page;
		cp = bufp->page;
		bufp->flags |= BUF_MOD;
	}

	/* Now move the data */
	for (space = FREESPACE(p) - BIGOVERHEAD; val_size;
	    space = FREESPACE(p) - BIGOVERHEAD) {
		move_bytes = MINIMUM(space, val_size);
		/*
		 * Here's the hack to make sure that if the data ends on the
		 * same page as the key ends, FREESPACE is at least one.
		 */
		if (space == val_size && val_size == val->size)
			move_bytes--;
		off = OFFSET(p) - move_bytes;
		memmove(cp + off, val_data, move_bytes);
		val_size -= move_bytes;
		val_data += move_bytes;
		n = p[0];
		p[++n] = off;
		p[0] = ++n;
		FREESPACE(p) = off - PAGE_META(n);
		OFFSET(p) = off;
		if (val_size) {
			p[n] = FULL_KEY;
			bufp = __add_ovflpage(hashp, bufp);
			if (!bufp)
				return (-1);
			cp = bufp->page;
			p = (u_int16_t *)cp;
		} else
			p[n] = FULL_KEY_DATA;
		bufp->flags |= BUF_MOD;
	}
	return (0);
}

/*
 * Called when bufp's page  contains a partial key (index should be 1)
 *
 * All pages in the big key/data pair except bufp are freed.  We cannot
 * free bufp because the page pointing to it is lost and we can't get rid
 * of its pointer.
 *
 * Returns:
 * 0 => OK
 *-1 => ERROR
 */
int
__big_delete(HTAB *hashp, BUFHEAD *bufp)
{
	BUFHEAD *last_bfp, *rbufp;
	u_int16_t *bp, pageno;
	int key_done, n;

	rbufp = bufp;
	last_bfp = NULL;
	bp = (u_int16_t *)bufp->page;
	pageno = 0;
	key_done = 0;

	while (!key_done || (bp[2] != FULL_KEY_DATA)) {
		if (bp[2] == FULL_KEY || bp[2] == FULL_KEY_DATA)
			key_done = 1;

		/*
		 * If there is freespace left on a FULL_KEY_DATA page, then
		 * the data is short and fits entirely on this page, and this
		 * is the last page.
		 */
		if (bp[2] == FULL_KEY_DATA && FREESPACE(bp))
			break;
		pageno = bp[bp[0] - 1];
		rbufp->flags |= BUF_MOD;
		rbufp = __get_buf(hashp, pageno, rbufp, 0);
		if (last_bfp)
			__free_ovflpage(hashp, last_bfp);
		last_bfp = rbufp;
		if (!rbufp)
			return (-1);		/* Error. */
		bp = (u_int16_t *)rbufp->page;
	}

	/*
	 * If we get here then rbufp points to the last page of the big
	 * key/data pair.  Bufp points to the first one -- it should now be
	 * empty pointing to the next page after this pair.  Can't free it
	 * because we don't have the page pointing to it.
	 */

	/* This is information from the last page of the pair. */
	n = bp[0];
	pageno = bp[n - 1];

	/* Now, bp is the first page of the pair. */
	bp = (u_int16_t *)bufp->page;
	if (n > 2) {
		/* There is an overflow page. */
		bp[1] = pageno;
		bp[2] = OVFLPAGE;
		bufp->ovfl = rbufp->ovfl;
	} else
		/* This is the last page. */
		bufp->ovfl = NULL;
	n -= 2;
	bp[0] = n;
	FREESPACE(bp) = hashp->BSIZE - PAGE_META(n);
	OFFSET(bp) = hashp->BSIZE;

	bufp->flags |= BUF_MOD;
	if (rbufp)
		__free_ovflpage(hashp, rbufp);
	if (last_bfp && last_bfp != rbufp)
		__free_ovflpage(hashp, last_bfp);

	hashp->NKEYS--;
	return (0);
}
/*
 * Returns:
 *  0 = key not found
 * -1 = get next overflow page
 * -2 means key not found and this is big key/data
 * -3 error
 */
int
__find_bigpair(HTAB *hashp, BUFHEAD *bufp, int ndx, char *key, int size)
{
	u_int16_t *bp;
	char *p;
	int ksize;
	u_int16_t bytes;
	char *kkey;

	bp = (u_int16_t *)bufp->page;
	p = bufp->page;
	ksize = size;
	kkey = key;

	for (bytes = hashp->BSIZE - bp[ndx];
	    bytes <= size && bp[ndx + 1] == PARTIAL_KEY;
	    bytes = hashp->BSIZE - bp[ndx]) {
		if (memcmp(p + bp[ndx], kkey, bytes))
			return (-2);
		kkey += bytes;
		ksize -= bytes;
		bufp = __get_buf(hashp, bp[ndx + 2], bufp, 0);
		if (!bufp)
			return (-3);
		p = bufp->page;
		bp = (u_int16_t *)p;
		ndx = 1;
	}

	if (bytes != ksize || memcmp(p + bp[ndx], kkey, bytes)) {
#ifdef HASH_STATISTICS
		++hash_collisions;
#endif
		return (-2);
	} else
		return (ndx);
}

/*
 * Given the buffer pointer of the first overflow page of a big pair,
 * find the end of the big pair
 *
 * This will set bpp to the buffer header of the last page of the big pair.
 * It will return the pageno of the overflow page following the last page
 * of the pair; 0 if there isn't any (i.e. big pair is the last key in the
 * bucket)
 */
u_int16_t
__find_last_page(HTAB *hashp, BUFHEAD **bpp)
{
	BUFHEAD *bufp;
	u_int16_t *bp, pageno;
	int n;

	bufp = *bpp;
	bp = (u_int16_t *)bufp->page;
	for (;;) {
		n = bp[0];

		/*
		 * This is the last page if: the tag is FULL_KEY_DATA and
		 * either only 2 entries OVFLPAGE marker is explicit there
		 * is freespace on the page.
		 */
		if (bp[2] == FULL_KEY_DATA &&
		    ((n == 2) || (bp[n] == OVFLPAGE) || (FREESPACE(bp))))
			break;

		pageno = bp[n - 1];
		bufp = __get_buf(hashp, pageno, bufp, 0);
		if (!bufp)
			return (0);	/* Need to indicate an error! */
		bp = (u_int16_t *)bufp->page;
	}

	*bpp = bufp;
	if (bp[0] > 2)
		return (bp[3]);
	else
		return (0);
}

/*
 * Return the data for the key/data pair that begins on this page at this
 * index (index should always be 1).
 */
int
__big_return(HTAB *hashp, BUFHEAD *bufp, int ndx, DBT *val, int set_current)
{
	BUFHEAD *save_p;
	u_int16_t *bp, len, off, save_addr;
	char *tp;

	bp = (u_int16_t *)bufp->page;
	while (bp[ndx + 1] == PARTIAL_KEY) {
		bufp = __get_buf(hashp, bp[bp[0] - 1], bufp, 0);
		if (!bufp)
			return (-1);
		bp = (u_int16_t *)bufp->page;
		ndx = 1;
	}

	if (bp[ndx + 1] == FULL_KEY) {
		bufp = __get_buf(hashp, bp[bp[0] - 1], bufp, 0);
		if (!bufp)
			return (-1);
		bp = (u_int16_t *)bufp->page;
		save_p = bufp;
		save_addr = save_p->addr;
		off = bp[1];
		len = 0;
	} else
		if (!FREESPACE(bp)) {
			/*
			 * This is a hack.  We can't distinguish between
			 * FULL_KEY_DATA that contains complete data or
			 * incomplete data, so we require that if the data
			 * is complete, there is at least 1 byte of free
			 * space left.
			 */
			off = bp[bp[0]];
			len = bp[1] - off;
			save_p = bufp;
			save_addr = bufp->addr;
			bufp = __get_buf(hashp, bp[bp[0] - 1], bufp, 0);
			if (!bufp)
				return (-1);
			bp = (u_int16_t *)bufp->page;
		} else {
			/* The data is all on one page. */
			tp = (char *)bp;
			off = bp[bp[0]];
			val->data = (u_char *)tp + off;
			val->size = bp[1] - off;
			if (set_current) {
				if (bp[0] == 2) {	/* No more buckets in
							 * chain */
					hashp->cpage = NULL;
					hashp->cbucket++;
					hashp->cndx = 1;
				} else {
					hashp->cpage = __get_buf(hashp,
					    bp[bp[0] - 1], bufp, 0);
					if (!hashp->cpage)
						return (-1);
					hashp->cndx = 1;
					if (!((u_int16_t *)
					    hashp->cpage->page)[0]) {
						hashp->cbucket++;
						hashp->cpage = NULL;
					}
				}
			}
			return (0);
		}

	val->size = (size_t)collect_data(hashp, bufp, (int)len, set_current);
	if (val->size == (size_t)-1)
		return (-1);
	if (save_p->addr != save_addr) {
		/* We are pretty short on buffers. */
		errno = EINVAL;			/* OUT OF BUFFERS */
		return (-1);
	}
	memmove(hashp->tmp_buf, (save_p->page) + off, len);
	val->data = (u_char *)hashp->tmp_buf;
	return (0);
}
/*
 * Count how big the total datasize is by recursing through the pages.  Then
 * allocate a buffer and copy the data as you recurse up.
 */
static int
collect_data(HTAB *hashp, BUFHEAD *bufp, int len, int set)
{
	u_int16_t *bp;
	char *p;
	BUFHEAD *xbp;
	u_int16_t save_addr;
	int mylen, totlen;

	p = bufp->page;
	bp = (u_int16_t *)p;
	mylen = hashp->BSIZE - bp[1];
	save_addr = bufp->addr;

	if (bp[2] == FULL_KEY_DATA) {		/* End of Data */
		totlen = len + mylen;
		free(hashp->tmp_buf);
		if ((hashp->tmp_buf = (char *)malloc(totlen)) == NULL)
			return (-1);
		if (set) {
			hashp->cndx = 1;
			if (bp[0] == 2) {	/* No more buckets in chain */
				hashp->cpage = NULL;
				hashp->cbucket++;
			} else {
				hashp->cpage =
				    __get_buf(hashp, bp[bp[0] - 1], bufp, 0);
				if (!hashp->cpage)
					return (-1);
				else if (!((u_int16_t *)hashp->cpage->page)[0]) {
					hashp->cbucket++;
					hashp->cpage = NULL;
				}
			}
		}
	} else {
		xbp = __get_buf(hashp, bp[bp[0] - 1], bufp, 0);
		if (!xbp || ((totlen =
		    collect_data(hashp, xbp, len + mylen, set)) < 1))
			return (-1);
	}
	if (bufp->addr != save_addr) {
		errno = EINVAL;			/* Out of buffers. */
		return (-1);
	}
	memmove(&hashp->tmp_buf[len], (bufp->page) + bp[1], mylen);
	return (totlen);
}

/*
 * Fill in the key and data for this big pair.
 */
int
__big_keydata(HTAB *hashp, BUFHEAD *bufp, DBT *key, DBT *val, int set)
{
	key->size = (size_t)collect_key(hashp, bufp, 0, val, set);
	if (key->size == (size_t)-1)
		return (-1);
	key->data = (u_char *)hashp->tmp_key;
	return (0);
}

/*
 * Count how big the total key size is by recursing through the pages.  Then
 * collect the data, allocate a buffer and copy the key as you recurse up.
 */
static int
collect_key(HTAB *hashp, BUFHEAD *bufp, int len, DBT *val, int set)
{
	BUFHEAD *xbp;
	char *p;
	int mylen, totlen;
	u_int16_t *bp, save_addr;

	p = bufp->page;
	bp = (u_int16_t *)p;
	mylen = hashp->BSIZE - bp[1];

	save_addr = bufp->addr;
	totlen = len + mylen;
	if (bp[2] == FULL_KEY || bp[2] == FULL_KEY_DATA) {    /* End of Key. */
		free(hashp->tmp_key);
		if ((hashp->tmp_key = (char *)malloc(totlen)) == NULL)
			return (-1);
		if (__big_return(hashp, bufp, 1, val, set))
			return (-1);
	} else {
		xbp = __get_buf(hashp, bp[bp[0] - 1], bufp, 0);
		if (!xbp || ((totlen =
		    collect_key(hashp, xbp, totlen, val, set)) < 1))
			return (-1);
	}
	if (bufp->addr != save_addr) {
		errno = EINVAL;		/* MIS -- OUT OF BUFFERS */
		return (-1);
	}
	memmove(&hashp->tmp_key[len], (bufp->page) + bp[1], mylen);
	return (totlen);
}

/*
 * Returns:
 *  0 => OK
 * -1 => error
 */
int
__big_split(HTAB *hashp,
    BUFHEAD *op,	/* Pointer to where to put keys that go in old bucket */
    BUFHEAD *np,	/* Pointer to new bucket page */
    BUFHEAD *big_keyp,	/* Pointer to first page containing the big key/data */
    int addr,		/* Address of big_keyp */
    u_int32_t obucket,	/* Old Bucket */
    SPLIT_RETURN *ret)
{
	BUFHEAD *bp, *tmpp;
	DBT key, val;
	u_int32_t change;
	u_int16_t free_space, n, off, *tp;

	bp = big_keyp;

	/* Now figure out where the big key/data goes */
	if (__big_keydata(hashp, big_keyp, &key, &val, 0))
		return (-1);
	change = (__call_hash(hashp, key.data, key.size) != obucket);

	if ((ret->next_addr = __find_last_page(hashp, &big_keyp))) {
		if (!(ret->nextp =
		    __get_buf(hashp, ret->next_addr, big_keyp, 0)))
			return (-1);
	} else
		ret->nextp = NULL;

	/* Now make one of np/op point to the big key/data pair */
#ifdef DEBUG
	assert(np->ovfl == NULL);
#endif
	if (change)
		tmpp = np;
	else
		tmpp = op;

	tmpp->flags |= BUF_MOD;
#ifdef DEBUG1
	(void)fprintf(stderr,
	    "BIG_SPLIT: %d->ovfl was %d is now %d\n", tmpp->addr,
	    (tmpp->ovfl ? tmpp->ovfl->addr : 0), (bp ? bp->addr : 0));
#endif
	tmpp->ovfl = bp;	/* one of op/np point to big_keyp */
	tp = (u_int16_t *)tmpp->page;
#ifdef DEBUG
	assert(FREESPACE(tp) >= OVFLSIZE);
#endif
	n = tp[0];
	off = OFFSET(tp);
	free_space = FREESPACE(tp);
	tp[++n] = (u_int16_t)addr;
	tp[++n] = OVFLPAGE;
	tp[0] = n;
	OFFSET(tp) = off;
	FREESPACE(tp) = free_space - OVFLSIZE;

	/*
	 * Finally, set the new and old return values. BIG_KEYP contains a
	 * pointer to the last page of the big key_data pair. Make sure that
	 * big_keyp has no following page (2 elements) or create an empty
	 * following page.
	 */

	ret->newp = np;
	ret->oldp = op;

	tp = (u_int16_t *)big_keyp->page;
	big_keyp->flags |= BUF_MOD;
	if (tp[0] > 2) {
		/*
		 * There may be either one or two offsets on this page.  If
		 * there is one, then the overflow page is linked on normally
		 * and tp[4] is OVFLPAGE.  If there are two, tp[4] contains
		 * the second offset and needs to get stuffed in after the
		 * next overflow page is added.
		 */
		n = tp[4];
		free_space = FREESPACE(tp);
		off = OFFSET(tp);
		tp[0] -= 2;
		FREESPACE(tp) = free_space + OVFLSIZE;
		OFFSET(tp) = off;
		tmpp = __add_ovflpage(hashp, big_keyp);
		if (!tmpp)
			return (-1);
		tp[4] = n;
	} else
		tmpp = big_keyp;

	if (change)
		ret->newp = tmpp;
	else
		ret->oldp = tmpp;
	return (0);
}


Generated by: GCOVR (Version 3.3)

Line	Branch	Exec	Source
1			/* $OpenBSD: hash_bigkey.c,v 1.19 2015/12/28 22:08:18 mmcc Exp $ */
2
3			/*-
4			* Copyright (c) 1990, 1993, 1994
5			* The Regents of the University of California. All rights reserved.
6			*
7			* This code is derived from software contributed to Berkeley by
8			* Margo Seltzer.
9			*
10			* Redistribution and use in source and binary forms, with or without
11			* modification, are permitted provided that the following conditions
12			* are met:
13			* 1. Redistributions of source code must retain the above copyright
14			* notice, this list of conditions and the following disclaimer.
15			* 2. Redistributions in binary form must reproduce the above copyright
16			* notice, this list of conditions and the following disclaimer in the
17			* documentation and/or other materials provided with the distribution.
18			* 3. Neither the name of the University nor the names of its contributors
19			* may be used to endorse or promote products derived from this software
20			* without specific prior written permission.
21			*
22			* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23			* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24			* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25			* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26			* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27			* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28			* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29			* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30			* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31			* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32			* SUCH DAMAGE.
33			*/
34
35			/*
36			* PACKAGE: hash
37			* DESCRIPTION:
38			* Big key/data handling for the hashing package.
39			*
40			* ROUTINES:
41			* External
42			* __big_keydata
43			* __big_split
44			* __big_insert
45			* __big_return
46			* __big_delete
47			* __find_last_page
48			* Internal
49			* collect_key
50			* collect_data
51			*/
52
53			#include <errno.h>
54			#include <stdio.h>
55			#include <stdlib.h>
56			#include <string.h>
57
58			#ifdef DEBUG
59			#include <assert.h>
60			#endif
61
62			#include <db.h>
63			#include "hash.h"
64			#include "page.h"
65			#include "extern.h"
66
67			#define MINIMUM(a, b) (((a) < (b)) ? (a) : (b))
68
69			static int collect_key(HTAB , BUFHEAD , int, DBT *, int);
70			static int collect_data(HTAB , BUFHEAD , int, int);
71
72			/*
73			* Big_insert
74			*
75			* You need to do an insert and the key/data pair is too big
76			*
77			* Returns:
78			* 0 ==> OK
79			*-1 ==> ERROR
80			*/
81			int
82			__big_insert(HTAB hashp, BUFHEAD bufp, const DBT key, const DBT val)
83			{
84			u_int16_t *p;
85			int key_size, n, val_size;
86			u_int16_t space, move_bytes, off;
87			char cp, key_data, *val_data;
88
89			cp = bufp->page; /* Character pointer of p. */
90			p = (u_int16_t *)cp;
91
92			key_data = (char *)key->data;
93			key_size = key->size;
94			val_data = (char *)val->data;
95			val_size = val->size;
96
97			/* First move the Key */
98			for (space = FREESPACE(p) - BIGOVERHEAD; key_size;
99			space = FREESPACE(p) - BIGOVERHEAD) {
100			move_bytes = MINIMUM(space, key_size);
101			off = OFFSET(p) - move_bytes;
102			memmove(cp + off, key_data, move_bytes);
103			key_size -= move_bytes;
104			key_data += move_bytes;
105			n = p[0];
106			p[++n] = off;
107			p[0] = ++n;
108			FREESPACE(p) = off - PAGE_META(n);
109			OFFSET(p) = off;
110			p[n] = PARTIAL_KEY;
111			bufp = __add_ovflpage(hashp, bufp);
112			if (!bufp)
113			return (-1);
114			n = p[0];
115			if (!key_size) {
116			space = FREESPACE(p);
117			if (space) {
118			move_bytes = MINIMUM(space, val_size);
119			/*
120			* If the data would fit exactly in the
121			* remaining space, we must overflow it to the
122			* next page; otherwise the invariant that the
123			* data must end on a page with FREESPACE
124			* non-zero would fail.
125			*/
126			if (space == val_size && val_size == val->size)
127			goto toolarge;
128			off = OFFSET(p) - move_bytes;
129			memmove(cp + off, val_data, move_bytes);
130			val_data += move_bytes;
131			val_size -= move_bytes;
132			p[n] = off;
133			p[n - 2] = FULL_KEY_DATA;
134			FREESPACE(p) = FREESPACE(p) - move_bytes;
135			OFFSET(p) = off;
136			} else {
137			toolarge:
138			p[n - 2] = FULL_KEY;
139			}
140			}
141			p = (u_int16_t *)bufp->page;
142			cp = bufp->page;
143			bufp->flags \|= BUF_MOD;
144			}
145
146			/* Now move the data */
147			for (space = FREESPACE(p) - BIGOVERHEAD; val_size;
148			space = FREESPACE(p) - BIGOVERHEAD) {
149			move_bytes = MINIMUM(space, val_size);
150			/*
151			* Here's the hack to make sure that if the data ends on the
152			* same page as the key ends, FREESPACE is at least one.
153			*/
154			if (space == val_size && val_size == val->size)
155			move_bytes--;
156			off = OFFSET(p) - move_bytes;
157			memmove(cp + off, val_data, move_bytes);
158			val_size -= move_bytes;
159			val_data += move_bytes;
160			n = p[0];
161			p[++n] = off;
162			p[0] = ++n;
163			FREESPACE(p) = off - PAGE_META(n);
164			OFFSET(p) = off;
165			if (val_size) {
166			p[n] = FULL_KEY;
167			bufp = __add_ovflpage(hashp, bufp);
168			if (!bufp)
169			return (-1);
170			cp = bufp->page;
171			p = (u_int16_t *)cp;
172			} else
173			p[n] = FULL_KEY_DATA;
174			bufp->flags \|= BUF_MOD;
175			}
176			return (0);
177			}
178
179			/*
180			* Called when bufp's page contains a partial key (index should be 1)
181			*
182			* All pages in the big key/data pair except bufp are freed. We cannot
183			* free bufp because the page pointing to it is lost and we can't get rid
184			* of its pointer.
185			*
186			* Returns:
187			* 0 => OK
188			*-1 => ERROR
189			*/
190			int
191			__big_delete(HTAB hashp, BUFHEAD bufp)
192			{
193			BUFHEAD last_bfp, rbufp;
194			u_int16_t *bp, pageno;
195			int key_done, n;
196
197			rbufp = bufp;
198			last_bfp = NULL;
199			bp = (u_int16_t *)bufp->page;
200			pageno = 0;
201			key_done = 0;
202
203			while (!key_done \|\| (bp[2] != FULL_KEY_DATA)) {
204			if (bp[2] == FULL_KEY \|\| bp[2] == FULL_KEY_DATA)
205			key_done = 1;
206
207			/*
208			* If there is freespace left on a FULL_KEY_DATA page, then
209			* the data is short and fits entirely on this page, and this
210			* is the last page.
211			*/
212			if (bp[2] == FULL_KEY_DATA && FREESPACE(bp))
213			break;
214			pageno = bp[bp[0] - 1];
215			rbufp->flags \|= BUF_MOD;
216			rbufp = __get_buf(hashp, pageno, rbufp, 0);
217			if (last_bfp)
218			__free_ovflpage(hashp, last_bfp);
219			last_bfp = rbufp;
220			if (!rbufp)
221			return (-1); /* Error. */
222			bp = (u_int16_t *)rbufp->page;
223			}
224
225			/*
226			* If we get here then rbufp points to the last page of the big
227			* key/data pair. Bufp points to the first one -- it should now be
228			* empty pointing to the next page after this pair. Can't free it
229			* because we don't have the page pointing to it.
230			*/
231
232			/* This is information from the last page of the pair. */
233			n = bp[0];
234			pageno = bp[n - 1];
235
236			/* Now, bp is the first page of the pair. */
237			bp = (u_int16_t *)bufp->page;
238			if (n > 2) {
239			/* There is an overflow page. */
240			bp[1] = pageno;
241			bp[2] = OVFLPAGE;
242			bufp->ovfl = rbufp->ovfl;
243			} else
244			/* This is the last page. */
245			bufp->ovfl = NULL;
246			n -= 2;
247			bp[0] = n;
248			FREESPACE(bp) = hashp->BSIZE - PAGE_META(n);
249			OFFSET(bp) = hashp->BSIZE;
250
251			bufp->flags \|= BUF_MOD;
252			if (rbufp)
253			__free_ovflpage(hashp, rbufp);
254			if (last_bfp && last_bfp != rbufp)
255			__free_ovflpage(hashp, last_bfp);
256
257			hashp->NKEYS--;
258			return (0);
259			}
260			/*
261			* Returns:
262			* 0 = key not found
263			* -1 = get next overflow page
264			* -2 means key not found and this is big key/data
265			* -3 error
266			*/
267			int
268			__find_bigpair(HTAB hashp, BUFHEAD bufp, int ndx, char *key, int size)
269			{
270			u_int16_t *bp;
271			char *p;
272			int ksize;
273			u_int16_t bytes;
274			char *kkey;
275
276			bp = (u_int16_t *)bufp->page;
277			p = bufp->page;
278			ksize = size;
279			kkey = key;
280
281			for (bytes = hashp->BSIZE - bp[ndx];
282			bytes <= size && bp[ndx + 1] == PARTIAL_KEY;
283			bytes = hashp->BSIZE - bp[ndx]) {
284			if (memcmp(p + bp[ndx], kkey, bytes))
285			return (-2);
286			kkey += bytes;
287			ksize -= bytes;
288			bufp = __get_buf(hashp, bp[ndx + 2], bufp, 0);
289			if (!bufp)
290			return (-3);
291			p = bufp->page;
292			bp = (u_int16_t *)p;
293			ndx = 1;
294			}
295
296			if (bytes != ksize \|\| memcmp(p + bp[ndx], kkey, bytes)) {
297			#ifdef HASH_STATISTICS
298			++hash_collisions;
299			#endif
300			return (-2);
301			} else
302			return (ndx);
303			}
304
305			/*
306			* Given the buffer pointer of the first overflow page of a big pair,
307			* find the end of the big pair
308			*
309			* This will set bpp to the buffer header of the last page of the big pair.
310			* It will return the pageno of the overflow page following the last page
311			* of the pair; 0 if there isn't any (i.e. big pair is the last key in the
312			* bucket)
313			*/
314			u_int16_t
315			__find_last_page(HTAB hashp, BUFHEAD *bpp)
316			{
317			BUFHEAD *bufp;
318			u_int16_t *bp, pageno;
319			int n;
320
321			bufp = *bpp;
322			bp = (u_int16_t *)bufp->page;
323			for (;;) {
324			n = bp[0];
325
326			/*
327			* This is the last page if: the tag is FULL_KEY_DATA and
328			* either only 2 entries OVFLPAGE marker is explicit there
329			* is freespace on the page.
330			*/
331			if (bp[2] == FULL_KEY_DATA &&
332			((n == 2) \|\| (bp[n] == OVFLPAGE) \|\| (FREESPACE(bp))))
333			break;
334
335			pageno = bp[n - 1];
336			bufp = __get_buf(hashp, pageno, bufp, 0);
337			if (!bufp)
338			return (0); /* Need to indicate an error! */
339			bp = (u_int16_t *)bufp->page;
340			}
341
342			*bpp = bufp;
343			if (bp[0] > 2)
344			return (bp[3]);
345			else
346			return (0);
347			}
348
349			/*
350			* Return the data for the key/data pair that begins on this page at this
351			* index (index should always be 1).
352			*/
353			int
354			__big_return(HTAB hashp, BUFHEAD bufp, int ndx, DBT *val, int set_current)
355			{
356			BUFHEAD *save_p;
357			u_int16_t *bp, len, off, save_addr;
358			char *tp;
359
360			bp = (u_int16_t *)bufp->page;
361			while (bp[ndx + 1] == PARTIAL_KEY) {
362			bufp = __get_buf(hashp, bp[bp[0] - 1], bufp, 0);
363			if (!bufp)
364			return (-1);
365			bp = (u_int16_t *)bufp->page;
366			ndx = 1;
367			}
368
369			if (bp[ndx + 1] == FULL_KEY) {
370			bufp = __get_buf(hashp, bp[bp[0] - 1], bufp, 0);
371			if (!bufp)
372			return (-1);
373			bp = (u_int16_t *)bufp->page;
374			save_p = bufp;
375			save_addr = save_p->addr;
376			off = bp[1];
377			len = 0;
378			} else
379			if (!FREESPACE(bp)) {
380			/*
381			* This is a hack. We can't distinguish between
382			* FULL_KEY_DATA that contains complete data or
383			* incomplete data, so we require that if the data
384			* is complete, there is at least 1 byte of free
385			* space left.
386			*/
387			off = bp[bp[0]];
388			len = bp[1] - off;
389			save_p = bufp;
390			save_addr = bufp->addr;
391			bufp = __get_buf(hashp, bp[bp[0] - 1], bufp, 0);
392			if (!bufp)
393			return (-1);
394			bp = (u_int16_t *)bufp->page;
395			} else {
396			/* The data is all on one page. */
397			tp = (char *)bp;
398			off = bp[bp[0]];
399			val->data = (u_char *)tp + off;
400			val->size = bp[1] - off;
401			if (set_current) {
402			if (bp[0] == 2) { /* No more buckets in
403			* chain */
404			hashp->cpage = NULL;
405			hashp->cbucket++;
406			hashp->cndx = 1;
407			} else {
408			hashp->cpage = __get_buf(hashp,
409			bp[bp[0] - 1], bufp, 0);
410			if (!hashp->cpage)
411			return (-1);
412			hashp->cndx = 1;
413			if (!((u_int16_t *)
414			hashp->cpage->page)[0]) {
415			hashp->cbucket++;
416			hashp->cpage = NULL;
417			}
418			}
419			}
420			return (0);
421			}
422
423			val->size = (size_t)collect_data(hashp, bufp, (int)len, set_current);
424			if (val->size == (size_t)-1)
425			return (-1);
426			if (save_p->addr != save_addr) {
427			/* We are pretty short on buffers. */
428			errno = EINVAL; /* OUT OF BUFFERS */
429			return (-1);
430			}
431			memmove(hashp->tmp_buf, (save_p->page) + off, len);
432			val->data = (u_char *)hashp->tmp_buf;
433			return (0);
434			}
435			/*
436			* Count how big the total datasize is by recursing through the pages. Then
437			* allocate a buffer and copy the data as you recurse up.
438			*/
439			static int
440			collect_data(HTAB hashp, BUFHEAD bufp, int len, int set)
441			{
442			u_int16_t *bp;
443			char *p;
444			BUFHEAD *xbp;
445			u_int16_t save_addr;
446			int mylen, totlen;
447
448			p = bufp->page;
449			bp = (u_int16_t *)p;
450			mylen = hashp->BSIZE - bp[1];
451			save_addr = bufp->addr;
452
453			if (bp[2] == FULL_KEY_DATA) { /* End of Data */
454			totlen = len + mylen;
455			free(hashp->tmp_buf);
456			if ((hashp->tmp_buf = (char *)malloc(totlen)) == NULL)
457			return (-1);
458			if (set) {
459			hashp->cndx = 1;
460			if (bp[0] == 2) { /* No more buckets in chain */
461			hashp->cpage = NULL;
462			hashp->cbucket++;
463			} else {
464			hashp->cpage =
465			__get_buf(hashp, bp[bp[0] - 1], bufp, 0);
466			if (!hashp->cpage)
467			return (-1);
468			else if (!((u_int16_t *)hashp->cpage->page)[0]) {
469			hashp->cbucket++;
470			hashp->cpage = NULL;
471			}
472			}
473			}
474			} else {
475			xbp = __get_buf(hashp, bp[bp[0] - 1], bufp, 0);
476			if (!xbp \|\| ((totlen =
477			collect_data(hashp, xbp, len + mylen, set)) < 1))
478			return (-1);
479			}
480			if (bufp->addr != save_addr) {
481			errno = EINVAL; /* Out of buffers. */
482			return (-1);
483			}
484			memmove(&hashp->tmp_buf[len], (bufp->page) + bp[1], mylen);
485			return (totlen);
486			}
487
488			/*
489			* Fill in the key and data for this big pair.
490			*/
491			int
492			__big_keydata(HTAB hashp, BUFHEAD bufp, DBT key, DBT val, int set)
493			{
494			key->size = (size_t)collect_key(hashp, bufp, 0, val, set);
495			if (key->size == (size_t)-1)
496			return (-1);
497			key->data = (u_char *)hashp->tmp_key;
498			return (0);
499			}
500
501			/*
502			* Count how big the total key size is by recursing through the pages. Then
503			* collect the data, allocate a buffer and copy the key as you recurse up.
504			*/
505			static int
506			collect_key(HTAB hashp, BUFHEAD bufp, int len, DBT *val, int set)
507			{
508			BUFHEAD *xbp;
509			char *p;
510			int mylen, totlen;
511			u_int16_t *bp, save_addr;
512
513			p = bufp->page;
514			bp = (u_int16_t *)p;
515			mylen = hashp->BSIZE - bp[1];
516
517			save_addr = bufp->addr;
518			totlen = len + mylen;
519			if (bp[2] == FULL_KEY \|\| bp[2] == FULL_KEY_DATA) { /* End of Key. */
520			free(hashp->tmp_key);
521			if ((hashp->tmp_key = (char *)malloc(totlen)) == NULL)
522			return (-1);
523			if (__big_return(hashp, bufp, 1, val, set))
524			return (-1);
525			} else {
526			xbp = __get_buf(hashp, bp[bp[0] - 1], bufp, 0);
527			if (!xbp \|\| ((totlen =
528			collect_key(hashp, xbp, totlen, val, set)) < 1))
529			return (-1);
530			}
531			if (bufp->addr != save_addr) {
532			errno = EINVAL; /* MIS -- OUT OF BUFFERS */
533			return (-1);
534			}
535			memmove(&hashp->tmp_key[len], (bufp->page) + bp[1], mylen);
536			return (totlen);
537			}
538
539			/*
540			* Returns:
541			* 0 => OK
542			* -1 => error
543			*/
544			int
545			__big_split(HTAB *hashp,
546			BUFHEAD op, / Pointer to where to put keys that go in old bucket */
547			BUFHEAD np, / Pointer to new bucket page */
548			BUFHEAD big_keyp, / Pointer to first page containing the big key/data */
549			int addr, /* Address of big_keyp */
550			u_int32_t obucket, /* Old Bucket */
551			SPLIT_RETURN *ret)
552			{
553			BUFHEAD bp, tmpp;
554			DBT key, val;
555			u_int32_t change;
556			u_int16_t free_space, n, off, *tp;
557
558			bp = big_keyp;
559
560			/* Now figure out where the big key/data goes */
561			if (__big_keydata(hashp, big_keyp, &key, &val, 0))
562			return (-1);
563			change = (__call_hash(hashp, key.data, key.size) != obucket);
564
565			if ((ret->next_addr = __find_last_page(hashp, &big_keyp))) {
566			if (!(ret->nextp =
567			__get_buf(hashp, ret->next_addr, big_keyp, 0)))
568			return (-1);
569			} else
570			ret->nextp = NULL;
571
572			/* Now make one of np/op point to the big key/data pair */
573			#ifdef DEBUG
574			assert(np->ovfl == NULL);
575			#endif
576			if (change)
577			tmpp = np;
578			else
579			tmpp = op;
580
581			tmpp->flags \|= BUF_MOD;
582			#ifdef DEBUG1
583			(void)fprintf(stderr,
584			"BIG_SPLIT: %d->ovfl was %d is now %d\n", tmpp->addr,
585			(tmpp->ovfl ? tmpp->ovfl->addr : 0), (bp ? bp->addr : 0));
586			#endif
587			tmpp->ovfl = bp; /* one of op/np point to big_keyp */
588			tp = (u_int16_t *)tmpp->page;
589			#ifdef DEBUG
590			assert(FREESPACE(tp) >= OVFLSIZE);
591			#endif
592			n = tp[0];
593			off = OFFSET(tp);
594			free_space = FREESPACE(tp);
595			tp[++n] = (u_int16_t)addr;
596			tp[++n] = OVFLPAGE;
597			tp[0] = n;
598			OFFSET(tp) = off;
599			FREESPACE(tp) = free_space - OVFLSIZE;
600
601			/*
602			* Finally, set the new and old return values. BIG_KEYP contains a
603			* pointer to the last page of the big key_data pair. Make sure that
604			* big_keyp has no following page (2 elements) or create an empty
605			* following page.
606			*/
607
608			ret->newp = np;
609			ret->oldp = op;
610
611			tp = (u_int16_t *)big_keyp->page;
612			big_keyp->flags \|= BUF_MOD;
613			if (tp[0] > 2) {
614			/*
615			* There may be either one or two offsets on this page. If
616			* there is one, then the overflow page is linked on normally
617			* and tp[4] is OVFLPAGE. If there are two, tp[4] contains
618			* the second offset and needs to get stuffed in after the
619			* next overflow page is added.
620			*/
621			n = tp[4];
622			free_space = FREESPACE(tp);
623			off = OFFSET(tp);
624			tp[0] -= 2;
625			FREESPACE(tp) = free_space + OVFLSIZE;
626			OFFSET(tp) = off;
627			tmpp = __add_ovflpage(hashp, big_keyp);
628			if (!tmpp)
629			return (-1);
630			tp[4] = n;
631			} else
632			tmpp = big_keyp;
633
634			if (change)
635			ret->newp = tmpp;
636			else
637			ret->oldp = tmpp;
638			return (0);
639			}