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-rw-r--r--db/recno/rec_delete.c197
1 files changed, 197 insertions, 0 deletions
diff --git a/db/recno/rec_delete.c b/db/recno/rec_delete.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[] = "@(#)rec_delete.c	8.7 (Berkeley) 7/14/94";
+#endif /* LIBC_SCCS and not lint */
+
+#include <sys/types.h>
+
+#include <errno.h>
+#include <stdio.h>
+#include <string.h>
+
+#include <db.h>
+#include "recno.h"
+
+static int rec_rdelete __P((BTREE *, recno_t));
+
+/*
+ * __REC_DELETE -- Delete the item(s) referenced by a key.
+ *
+ * Parameters:
+ *	dbp:	pointer to access method
+ *	key:	key to delete
+ *	flags:	R_CURSOR if deleting what the cursor references
+ *
+ * Returns:
+ *	RET_ERROR, RET_SUCCESS and RET_SPECIAL if the key not found.
+ */
+int
+__rec_delete(dbp, key, flags)
+	const DB *dbp;
+	const DBT *key;
+	u_int flags;
+{
+	BTREE *t;
+	recno_t nrec;
+	int status;
+
+	t = dbp->internal;
+
+	/* Toss any page pinned across calls. */
+	if (t->bt_pinned != NULL) {
+		mpool_put(t->bt_mp, t->bt_pinned, 0);
+		t->bt_pinned = NULL;
+	}
+
+	switch(flags) {
+	case 0:
+		if ((nrec = *(recno_t *)key->data) == 0)
+			goto einval;
+		if (nrec > t->bt_nrecs)
+			return (RET_SPECIAL);
+		--nrec;
+		status = rec_rdelete(t, nrec);
+		break;
+	case R_CURSOR:
+		if (!F_ISSET(&t->bt_cursor, CURS_INIT))
+			goto einval;
+		if (t->bt_nrecs == 0)
+			return (RET_SPECIAL);
+		status = rec_rdelete(t, t->bt_cursor.rcursor - 1);
+		if (status == RET_SUCCESS)
+			--t->bt_cursor.rcursor;
+		break;
+	default:
+einval:		errno = EINVAL;
+		return (RET_ERROR);
+	}
+
+	if (status == RET_SUCCESS)
+		F_SET(t, B_MODIFIED | R_MODIFIED);
+	return (status);
+}
+
+/*
+ * REC_RDELETE -- Delete the data matching the specified key.
+ *
+ * Parameters:
+ *	tree:	tree
+ *	nrec:	record to delete
+ *
+ * Returns:
+ *	RET_ERROR, RET_SUCCESS and RET_SPECIAL if the key not found.
+ */
+static int
+rec_rdelete(t, nrec)
+	BTREE *t;
+	recno_t nrec;
+{
+	EPG *e;
+	PAGE *h;
+	int status;
+
+	/* Find the record; __rec_search pins the page. */
+	if ((e = __rec_search(t, nrec, SDELETE)) == NULL)
+		return (RET_ERROR);
+
+	/* Delete the record. */
+	h = e->page;
+	status = __rec_dleaf(t, h, e->index);
+	if (status != RET_SUCCESS) {
+		mpool_put(t->bt_mp, h, 0);
+		return (status);
+	}
+	mpool_put(t->bt_mp, h, MPOOL_DIRTY);
+	return (RET_SUCCESS);
+}
+
+/*
+ * __REC_DLEAF -- Delete a single record from a recno leaf page.
+ *
+ * Parameters:
+ *	t:	tree
+ *	index:	index on current page to delete
+ *
+ * Returns:
+ *	RET_SUCCESS, RET_ERROR.
+ */
+int
+__rec_dleaf(t, h, index)
+	BTREE *t;
+	PAGE *h;
+	u_int32_t index;
+{
+	RLEAF *rl;
+	indx_t *ip, cnt, offset;
+	u_int32_t nbytes;
+	char *from;
+	void *to;
+
+	/*
+	 * Delete a record from a recno leaf page.  Internal records are never
+	 * deleted from internal pages, regardless of the records that caused
+	 * them to be added being deleted.  Pages made empty by deletion are
+	 * not reclaimed.  They are, however, made available for reuse.
+	 *
+	 * Pack the remaining entries at the end of the page, shift the indices
+	 * down, overwriting the deleted record and its index.  If the record
+	 * uses overflow pages, make them available for reuse.
+	 */
+	to = rl = GETRLEAF(h, index);
+	if (rl->flags & P_BIGDATA && __ovfl_delete(t, rl->bytes) == RET_ERROR)
+		return (RET_ERROR);
+	nbytes = NRLEAF(rl);
+
+	/*
+	 * Compress the key/data pairs.  Compress and adjust the [BR]LEAF
+	 * offsets.  Reset the headers.
+	 */
+	from = (char *)h + h->upper;
+	memmove(from + nbytes, from, (char *)to - from);
+	h->upper += nbytes;
+
+	offset = h->linp[index];
+	for (cnt = &h->linp[index] - (ip = &h->linp[0]); cnt--; ++ip)
+		if (ip[0] < offset)
+			ip[0] += nbytes;
+	for (cnt = &h->linp[NEXTINDEX(h)] - ip; --cnt; ++ip)
+		ip[0] = ip[1] < offset ? ip[1] + nbytes : ip[1];
+	h->lower -= sizeof(indx_t);
+	--t->bt_nrecs;
+	return (RET_SUCCESS);
+}