about summary refs log tree commit diff
path: root/db/btree/bt_overflow.c
diff options
context:
space:
mode:
authorRoland McGrath <roland@gnu.org>1996-01-02 08:57:42 +0000
committerRoland McGrath <roland@gnu.org>1996-01-02 08:57:42 +0000
commit71733723fb421bd54467d1a27096463ed1dcc2ed (patch)
treef304556d491722c797d876911834dc4afbfa2740 /db/btree/bt_overflow.c
parentfc4026d8e43407ba2739e493878d1ce259500059 (diff)
downloadglibc-71733723fb421bd54467d1a27096463ed1dcc2ed.tar.gz
glibc-71733723fb421bd54467d1a27096463ed1dcc2ed.tar.xz
glibc-71733723fb421bd54467d1a27096463ed1dcc2ed.zip
* hurd/hurd/signal.h (struct hurd_sigstate): New member `preempters'. cvs/libc-960102
	(hurd_preempt_signals, hurd_unpreempt_signals): Decls removed.
	* hurd/hurd/sigpreempt.h: New file.
	* hurd/preempt-sig.c: Rewritten with new interface.
	* sysdeps/mach/hurd/jmp-unwind.c (_longjmp_unwind): Remove local signal
	preempters being unwound past.

	* db: New directory, 4.4 BSD db package incorporated from BSD db-1.85
	release.

	* sysdeps/unix/sysv/linux/sys/param.h: Several new macros for BSD
	compatibility.
Diffstat (limited to 'db/btree/bt_overflow.c')
-rw-r--r--db/btree/bt_overflow.c228
1 files changed, 228 insertions, 0 deletions
diff --git a/db/btree/bt_overflow.c b/db/btree/bt_overflow.c
new file mode 100644
index 0000000000..b28b8e0471
--- /dev/null
+++ b/db/btree/bt_overflow.c
@@ -0,0 +1,228 @@
+/*-
+ * 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_overflow.c	8.5 (Berkeley) 7/16/94";
+#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"
+
+/*
+ * Big key/data code.
+ *
+ * Big key and data entries are stored on linked lists of pages.  The initial
+ * reference is byte string stored with the key or data and is the page number
+ * and size.  The actual record is stored in a chain of pages linked by the
+ * nextpg field of the PAGE header.
+ *
+ * The first page of the chain has a special property.  If the record is used
+ * by an internal page, it cannot be deleted and the P_PRESERVE bit will be set
+ * in the header.
+ *
+ * XXX
+ * A single DBT is written to each chain, so a lot of space on the last page
+ * is wasted.  This is a fairly major bug for some data sets.
+ */
+
+/*
+ * __OVFL_GET -- Get an overflow key/data item.
+ *
+ * Parameters:
+ *	t:	tree
+ *	p:	pointer to { pgno_t, u_int32_t }
+ *	buf:	storage address
+ *	bufsz:	storage size
+ *
+ * Returns:
+ *	RET_ERROR, RET_SUCCESS
+ */
+int
+__ovfl_get(t, p, ssz, buf, bufsz)
+	BTREE *t;
+	void *p;
+	size_t *ssz;
+	void **buf;
+	size_t *bufsz;
+{
+	PAGE *h;
+	pgno_t pg;
+	size_t nb, plen;
+	u_int32_t sz;
+
+	memmove(&pg, p, sizeof(pgno_t));
+	memmove(&sz, (char *)p + sizeof(pgno_t), sizeof(u_int32_t));
+	*ssz = sz;
+
+#ifdef DEBUG
+	if (pg == P_INVALID || sz == 0)
+		abort();
+#endif
+	/* Make the buffer bigger as necessary. */
+	if (*bufsz < sz) {
+		*buf = (char *)(*buf == NULL ? malloc(sz) : realloc(*buf, sz));
+		if (*buf == NULL)
+			return (RET_ERROR);
+		*bufsz = sz;
+	}
+
+	/*
+	 * Step through the linked list of pages, copying the data on each one
+	 * into the buffer.  Never copy more than the data's length.
+	 */
+	plen = t->bt_psize - BTDATAOFF;
+	for (p = *buf;; p = (char *)p + nb, pg = h->nextpg) {
+		if ((h = mpool_get(t->bt_mp, pg, 0)) == NULL)
+			return (RET_ERROR);
+
+		nb = MIN(sz, plen);
+		memmove(p, (char *)h + BTDATAOFF, nb);
+		mpool_put(t->bt_mp, h, 0);
+
+		if ((sz -= nb) == 0)
+			break;
+	}
+	return (RET_SUCCESS);
+}
+
+/*
+ * __OVFL_PUT -- Store an overflow key/data item.
+ *
+ * Parameters:
+ *	t:	tree
+ *	data:	DBT to store
+ *	pgno:	storage page number
+ *
+ * Returns:
+ *	RET_ERROR, RET_SUCCESS
+ */
+int
+__ovfl_put(t, dbt, pg)
+	BTREE *t;
+	const DBT *dbt;
+	pgno_t *pg;
+{
+	PAGE *h, *last;
+	void *p;
+	pgno_t npg;
+	size_t nb, plen;
+	u_int32_t sz;
+
+	/*
+	 * Allocate pages and copy the key/data record into them.  Store the
+	 * number of the first page in the chain.
+	 */
+	plen = t->bt_psize - BTDATAOFF;
+	for (last = NULL, p = dbt->data, sz = dbt->size;;
+	    p = (char *)p + plen, last = h) {
+		if ((h = __bt_new(t, &npg)) == NULL)
+			return (RET_ERROR);
+
+		h->pgno = npg;
+		h->nextpg = h->prevpg = P_INVALID;
+		h->flags = P_OVERFLOW;
+		h->lower = h->upper = 0;
+
+		nb = MIN(sz, plen);
+		memmove((char *)h + BTDATAOFF, p, nb);
+
+		if (last) {
+			last->nextpg = h->pgno;
+			mpool_put(t->bt_mp, last, MPOOL_DIRTY);
+		} else
+			*pg = h->pgno;
+
+		if ((sz -= nb) == 0) {
+			mpool_put(t->bt_mp, h, MPOOL_DIRTY);
+			break;
+		}
+	}
+	return (RET_SUCCESS);
+}
+
+/*
+ * __OVFL_DELETE -- Delete an overflow chain.
+ *
+ * Parameters:
+ *	t:	tree
+ *	p:	pointer to { pgno_t, u_int32_t }
+ *
+ * Returns:
+ *	RET_ERROR, RET_SUCCESS
+ */
+int
+__ovfl_delete(t, p)
+	BTREE *t;
+	void *p;
+{
+	PAGE *h;
+	pgno_t pg;
+	size_t plen;
+	u_int32_t sz;
+
+	memmove(&pg, p, sizeof(pgno_t));
+	memmove(&sz, (char *)p + sizeof(pgno_t), sizeof(u_int32_t));
+
+#ifdef DEBUG
+	if (pg == P_INVALID || sz == 0)
+		abort();
+#endif
+	if ((h = mpool_get(t->bt_mp, pg, 0)) == NULL)
+		return (RET_ERROR);
+
+	/* Don't delete chains used by internal pages. */
+	if (h->flags & P_PRESERVE) {
+		mpool_put(t->bt_mp, h, 0);
+		return (RET_SUCCESS);
+	}
+
+	/* Step through the chain, calling the free routine for each page. */
+	for (plen = t->bt_psize - BTDATAOFF;; sz -= plen) {
+		pg = h->nextpg;
+		__bt_free(t, h);
+		if (sz <= plen)
+			break;
+		if ((h = mpool_get(t->bt_mp, pg, 0)) == NULL)
+			return (RET_ERROR);
+	}
+	return (RET_SUCCESS);
+}