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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/recno/rec_search.c
parentfc4026d8e43407ba2739e493878d1ce259500059 (diff)
downloadglibc-71733723fb421bd54467d1a27096463ed1dcc2ed.tar.gz
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* 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/recno/rec_search.c')
-rw-r--r--db/recno/rec_search.c126
1 files changed, 126 insertions, 0 deletions
diff --git a/db/recno/rec_search.c b/db/recno/rec_search.c
new file mode 100644
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--- /dev/null
+++ b/db/recno/rec_search.c
@@ -0,0 +1,126 @@
+/*-
+ * Copyright (c) 1990, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * 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[] = "@(#)rec_search.c	8.4 (Berkeley) 7/14/94";
+#endif /* LIBC_SCCS and not lint */
+
+#include <sys/types.h>
+
+#include <errno.h>
+#include <stdio.h>
+
+#include <db.h>
+#include "recno.h"
+
+/*
+ * __REC_SEARCH -- Search a btree for a key.
+ *
+ * Parameters:
+ *	t:	tree to search
+ *	recno:	key to find
+ *	op: 	search operation
+ *
+ * Returns:
+ *	EPG for matching record, if any, or the EPG for the location of the
+ *	key, if it were inserted into the tree.
+ *
+ * Returns:
+ *	The EPG for matching record, if any, or the EPG for the location
+ *	of the key, if it were inserted into the tree, is entered into
+ *	the bt_cur field of the tree.  A pointer to the field is returned.
+ */
+EPG *
+__rec_search(t, recno, op)
+	BTREE *t;
+	recno_t recno;
+	enum SRCHOP op;
+{
+	register indx_t index;
+	register PAGE *h;
+	EPGNO *parent;
+	RINTERNAL *r;
+	pgno_t pg;
+	indx_t top;
+	recno_t total;
+	int sverrno;
+
+	BT_CLR(t);
+	for (pg = P_ROOT, total = 0;;) {
+		if ((h = mpool_get(t->bt_mp, pg, 0)) == NULL)
+			goto err;
+		if (h->flags & P_RLEAF) {
+			t->bt_cur.page = h;
+			t->bt_cur.index = recno - total;
+			return (&t->bt_cur);
+		}
+		for (index = 0, top = NEXTINDEX(h);;) {
+			r = GETRINTERNAL(h, index);
+			if (++index == top || total + r->nrecs > recno)
+				break;
+			total += r->nrecs;
+		}
+
+		BT_PUSH(t, pg, index - 1);
+		
+		pg = r->pgno;
+		switch (op) {
+		case SDELETE:
+			--GETRINTERNAL(h, (index - 1))->nrecs;
+			mpool_put(t->bt_mp, h, MPOOL_DIRTY);
+			break;
+		case SINSERT:
+			++GETRINTERNAL(h, (index - 1))->nrecs;
+			mpool_put(t->bt_mp, h, MPOOL_DIRTY);
+			break;
+		case SEARCH:
+			mpool_put(t->bt_mp, h, 0);
+			break;
+		}
+
+	}
+	/* Try and recover the tree. */
+err:	sverrno = errno;
+	if (op != SEARCH)
+		while  ((parent = BT_POP(t)) != NULL) {
+			if ((h = mpool_get(t->bt_mp, parent->pgno, 0)) == NULL)
+				break;
+			if (op == SINSERT)
+				--GETRINTERNAL(h, parent->index)->nrecs;
+			else
+				++GETRINTERNAL(h, parent->index)->nrecs;
+                        mpool_put(t->bt_mp, h, MPOOL_DIRTY);
+                }
+	errno = sverrno;
+	return (NULL);
+}