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-rw-r--r--db/btree/bt_utils.c260
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diff --git a/db/btree/bt_utils.c b/db/btree/bt_utils.c
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+/*-
+ * 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
+ * Mike Olson.
+ *
+ * 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[] = "@(#)bt_utils.c	8.8 (Berkeley) 7/20/94";
+#endif /* LIBC_SCCS and not lint */
+
+#include <sys/param.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <db.h>
+#include "btree.h"
+
+/*
+ * __bt_ret --
+ *	Build return key/data pair.
+ *
+ * Parameters:
+ *	t:	tree
+ *	e:	key/data pair to be returned
+ *	key:	user's key structure (NULL if not to be filled in)
+ *	rkey:	memory area to hold key
+ *	data:	user's data structure (NULL if not to be filled in)
+ *	rdata:	memory area to hold data
+ *       copy:	always copy the key/data item
+ *
+ * Returns:
+ *	RET_SUCCESS, RET_ERROR.
+ */
+int
+__bt_ret(t, e, key, rkey, data, rdata, copy)
+	BTREE *t;
+	EPG *e;
+	DBT *key, *rkey, *data, *rdata;
+	int copy;
+{
+	BLEAF *bl;
+	void *p;
+
+	bl = GETBLEAF(e->page, e->index);
+
+	/*
+	 * We must copy big keys/data to make them contigous.  Otherwise,
+	 * leave the page pinned and don't copy unless the user specified
+	 * concurrent access.
+	 */
+	if (key == NULL)
+		goto dataonly;
+
+	if (bl->flags & P_BIGKEY) {
+		if (__ovfl_get(t, bl->bytes,
+		    &key->size, &rkey->data, &rkey->size))
+			return (RET_ERROR);
+		key->data = rkey->data;
+	} else if (copy || F_ISSET(t, B_DB_LOCK)) {
+		if (bl->ksize > rkey->size) {
+			p = (void *)(rkey->data == NULL ?
+			    malloc(bl->ksize) : realloc(rkey->data, bl->ksize));
+			if (p == NULL)
+				return (RET_ERROR);
+			rkey->data = p;
+			rkey->size = bl->ksize;
+		}
+		memmove(rkey->data, bl->bytes, bl->ksize);
+		key->size = bl->ksize;
+		key->data = rkey->data;
+	} else {
+		key->size = bl->ksize;
+		key->data = bl->bytes;
+	}
+
+dataonly:
+	if (data == NULL)
+		return (RET_SUCCESS);
+
+	if (bl->flags & P_BIGDATA) {
+		if (__ovfl_get(t, bl->bytes + bl->ksize,
+		    &data->size, &rdata->data, &rdata->size))
+			return (RET_ERROR);
+		data->data = rdata->data;
+	} else if (copy || F_ISSET(t, B_DB_LOCK)) {
+		/* Use +1 in case the first record retrieved is 0 length. */
+		if (bl->dsize + 1 > rdata->size) {
+			p = (void *)(rdata->data == NULL ?
+			    malloc(bl->dsize + 1) :
+			    realloc(rdata->data, bl->dsize + 1));
+			if (p == NULL)
+				return (RET_ERROR);
+			rdata->data = p;
+			rdata->size = bl->dsize + 1;
+		}
+		memmove(rdata->data, bl->bytes + bl->ksize, bl->dsize);
+		data->size = bl->dsize;
+		data->data = rdata->data;
+	} else {
+		data->size = bl->dsize;
+		data->data = bl->bytes + bl->ksize;
+	}
+
+	return (RET_SUCCESS);
+}
+
+/*
+ * __BT_CMP -- Compare a key to a given record.
+ *
+ * Parameters:
+ *	t:	tree
+ *	k1:	DBT pointer of first arg to comparison
+ *	e:	pointer to EPG for comparison
+ *
+ * Returns:
+ *	< 0 if k1 is < record
+ *	= 0 if k1 is = record
+ *	> 0 if k1 is > record
+ */
+int
+__bt_cmp(t, k1, e)
+	BTREE *t;
+	const DBT *k1;
+	EPG *e;
+{
+	BINTERNAL *bi;
+	BLEAF *bl;
+	DBT k2;
+	PAGE *h;
+	void *bigkey;
+
+	/*
+	 * The left-most key on internal pages, at any level of the tree, is
+	 * guaranteed by the following code to be less than any user key.
+	 * This saves us from having to update the leftmost key on an internal
+	 * page when the user inserts a new key in the tree smaller than
+	 * anything we've yet seen.
+	 */
+	h = e->page;
+	if (e->index == 0 && h->prevpg == P_INVALID && !(h->flags & P_BLEAF))
+		return (1);
+
+	bigkey = NULL;
+	if (h->flags & P_BLEAF) {
+		bl = GETBLEAF(h, e->index);
+		if (bl->flags & P_BIGKEY)
+			bigkey = bl->bytes;
+		else {
+			k2.data = bl->bytes;
+			k2.size = bl->ksize;
+		}
+	} else {
+		bi = GETBINTERNAL(h, e->index);
+		if (bi->flags & P_BIGKEY)
+			bigkey = bi->bytes;
+		else {
+			k2.data = bi->bytes;
+			k2.size = bi->ksize;
+		}
+	}
+
+	if (bigkey) {
+		if (__ovfl_get(t, bigkey,
+		    &k2.size, &t->bt_rdata.data, &t->bt_rdata.size))
+			return (RET_ERROR);
+		k2.data = t->bt_rdata.data;
+	}
+	return ((*t->bt_cmp)(k1, &k2));
+}
+
+/*
+ * __BT_DEFCMP -- Default comparison routine.
+ *
+ * Parameters:
+ *	a:	DBT #1
+ *	b: 	DBT #2
+ *
+ * Returns:
+ *	< 0 if a is < b
+ *	= 0 if a is = b
+ *	> 0 if a is > b
+ */
+int
+__bt_defcmp(a, b)
+	const DBT *a, *b;
+{
+	register size_t len;
+	register u_char *p1, *p2;
+
+	/*
+	 * XXX
+	 * If a size_t doesn't fit in an int, this routine can lose.
+	 * What we need is a integral type which is guaranteed to be
+	 * larger than a size_t, and there is no such thing.
+	 */
+	len = MIN(a->size, b->size);
+	for (p1 = a->data, p2 = b->data; len--; ++p1, ++p2)
+		if (*p1 != *p2)
+			return ((int)*p1 - (int)*p2);
+	return ((int)a->size - (int)b->size);
+}
+
+/*
+ * __BT_DEFPFX -- Default prefix routine.
+ *
+ * Parameters:
+ *	a:	DBT #1
+ *	b: 	DBT #2
+ *
+ * Returns:
+ *	Number of bytes needed to distinguish b from a.
+ */
+size_t
+__bt_defpfx(a, b)
+	const DBT *a, *b;
+{
+	register u_char *p1, *p2;
+	register size_t cnt, len;
+
+	cnt = 1;
+	len = MIN(a->size, b->size);
+	for (p1 = a->data, p2 = b->data; len--; ++p1, ++p2, ++cnt)
+		if (*p1 != *p2)
+			return (cnt);
+
+	/* a->size must be <= b->size, or they wouldn't be in this order. */
+	return (a->size < b->size ? a->size + 1 : a->size);
+}
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