DtMmdb: move to lib directory as a standalone library.
This commit is contained in:
Liang Chang
391
cde/lib/DtMmdb/btree_berkeley/bt_seq.c
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391
cde/lib/DtMmdb/btree_berkeley/bt_seq.c
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@@ -0,0 +1,391 @@
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/*
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* CDE - Common Desktop Environment
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*
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* Copyright (c) 1993-2012, The Open Group. All rights reserved.
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*
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* These libraries and programs are free software; you can
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* redistribute them and/or modify them under the terms of the GNU
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* Lesser General Public License as published by the Free Software
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* Foundation; either version 2 of the License, or (at your option)
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* any later version.
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*
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* These libraries and programs are distributed in the hope that
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* they will be useful, but WITHOUT ANY WARRANTY; without even the
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* implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
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* PURPOSE. See the GNU Lesser General Public License for more
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* details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with these libraries and programs; if not, write
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* to the Free Software Foundation, Inc., 51 Franklin Street, Fifth
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* Floor, Boston, MA 02110-1301 USA
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*/
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/* $XConsortium: bt_seq.c /main/3 1996/06/11 17:13:05 cde-hal $ */
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/*-
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* Copyright (c) 1990, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* Mike Olson.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#if defined(LIBC_SCCS) && !defined(lint)
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static char sccsid[] = "@(#)bt_seq.c 8.2 (Berkeley) 9/7/93";
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#endif /* LIBC_SCCS and not lint */
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#include <sys/types.h>
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#include <errno.h>
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#include <stddef.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <db.h>
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#include "btree.h"
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static int bt_seqadv __P((BTREE *, EPG *, int));
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static int bt_seqset __P((BTREE *, EPG *, DBT *, int));
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/*
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* Sequential scan support.
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*
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* The tree can be scanned sequentially, starting from either end of the tree
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* or from any specific key. A scan request before any scanning is done is
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* initialized as starting from the least node.
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*
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* Each tree has an EPGNO which has the current position of the cursor. The
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* cursor has to survive deletions/insertions in the tree without losing its
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* position. This is done by noting deletions without doing them, and then
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* doing them when the cursor moves (or the tree is closed).
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*/
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/*
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* __BT_SEQ -- Btree sequential scan interface.
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*
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* Parameters:
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* dbp: pointer to access method
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* key: key for positioning and return value
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* data: data return value
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* flags: R_CURSOR, R_FIRST, R_LAST, R_NEXT, R_PREV.
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*
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* Returns:
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* RET_ERROR, RET_SUCCESS or RET_SPECIAL if there's no next key.
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*/
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int
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__bt_seq(const DB *dbp, DBT *key, DBT *data, u_int flags)
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{
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BTREE *t;
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EPG e;
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int status;
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t = dbp->internal;
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/* Toss any page pinned across calls. */
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if (t->bt_pinned != NULL) {
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mpool_put(t->bt_mp, t->bt_pinned, 0);
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t->bt_pinned = NULL;
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}
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/*
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* If scan unitialized as yet, or starting at a specific record, set
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* the scan to a specific key. Both bt_seqset and bt_seqadv pin the
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* page the cursor references if they're successful.
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*/
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switch(flags) {
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case R_NEXT:
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case R_PREV:
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if (ISSET(t, B_SEQINIT)) {
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status = bt_seqadv(t, &e, flags);
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break;
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}
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/* FALLTHROUGH */
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case R_CURSOR:
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case R_FIRST:
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case R_LAST:
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status = bt_seqset(t, &e, key, flags);
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break;
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default:
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errno = EINVAL;
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return (RET_ERROR);
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}
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if (status == RET_SUCCESS) {
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status = __bt_ret(t, &e, key, data);
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/* Update the actual cursor. */
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t->bt_bcursor.pgno = e.page->pgno;
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t->bt_bcursor.index = e.index;
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/*
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* If the user is doing concurrent access, we copied the
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* key/data, toss the page.
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*/
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if (ISSET(t, B_DB_LOCK))
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mpool_put(t->bt_mp, e.page, 0);
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else
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t->bt_pinned = e.page;
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SET(t, B_SEQINIT);
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}
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return (status);
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}
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/*
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* BT_SEQSET -- Set the sequential scan to a specific key.
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*
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* Parameters:
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* t: tree
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* ep: storage for returned key
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* key: key for initial scan position
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* flags: R_CURSOR, R_FIRST, R_LAST, R_NEXT, R_PREV
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*
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* Side effects:
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* Pins the page the cursor references.
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*
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* Returns:
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* RET_ERROR, RET_SUCCESS or RET_SPECIAL if there's no next key.
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*/
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static int
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bt_seqset(BTREE *t, EPG *ep, DBT *key, int flags)
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{
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EPG *e;
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PAGE *h;
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pgno_t pg;
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int exact;
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/*
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* Delete any already deleted record that we've been saving because
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* the cursor pointed to it. Since going to a specific key, should
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* delete any logically deleted records so they aren't found.
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*/
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if (ISSET(t, B_DELCRSR) && __bt_crsrdel(t, &t->bt_bcursor))
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return (RET_ERROR);
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/*
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* Find the first, last or specific key in the tree and point the cursor
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* at it. The cursor may not be moved until a new key has been found.
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*/
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switch(flags) {
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case R_CURSOR: /* Keyed scan. */
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/*
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* Find the first instance of the key or the smallest key which
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* is greater than or equal to the specified key. If run out
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* of keys, return RET_SPECIAL.
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*/
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if (key->data == NULL || key->size == 0) {
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errno = EINVAL;
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return (RET_ERROR);
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}
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e = __bt_first(t, key, &exact); /* Returns pinned page. */
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if (e == NULL)
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return (RET_ERROR);
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/*
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* If at the end of a page, skip any empty pages and find the
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* next entry.
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*/
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if (e->index == NEXTINDEX(e->page)) {
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h = e->page;
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do {
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pg = h->nextpg;
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mpool_put(t->bt_mp, h, 0);
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if (pg == P_INVALID)
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return (RET_SPECIAL);
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if ((h = mpool_get(t->bt_mp, pg, 0)) == NULL)
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return (RET_ERROR);
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} while (NEXTINDEX(h) == 0);
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e->index = 0;
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e->page = h;
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}
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*ep = *e;
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break;
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case R_FIRST: /* First record. */
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case R_NEXT:
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/* Walk down the left-hand side of the tree. */
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for (pg = P_ROOT;;) {
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if ((h = mpool_get(t->bt_mp, pg, 0)) == NULL)
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return (RET_ERROR);
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if (h->flags & (P_BLEAF | P_RLEAF))
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break;
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pg = GETBINTERNAL(h, 0)->pgno;
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mpool_put(t->bt_mp, h, 0);
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}
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/* Skip any empty pages. */
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while (NEXTINDEX(h) == 0 && h->nextpg != P_INVALID) {
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pg = h->nextpg;
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mpool_put(t->bt_mp, h, 0);
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if ((h = mpool_get(t->bt_mp, pg, 0)) == NULL)
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return (RET_ERROR);
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}
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if (NEXTINDEX(h) == 0) {
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mpool_put(t->bt_mp, h, 0);
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return (RET_SPECIAL);
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}
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ep->page = h;
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ep->index = 0;
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break;
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case R_LAST: /* Last record. */
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case R_PREV:
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/* Walk down the right-hand side of the tree. */
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for (pg = P_ROOT;;) {
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if ((h = mpool_get(t->bt_mp, pg, 0)) == NULL)
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return (RET_ERROR);
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if (h->flags & (P_BLEAF | P_RLEAF))
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break;
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pg = GETBINTERNAL(h, NEXTINDEX(h) - 1)->pgno;
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mpool_put(t->bt_mp, h, 0);
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}
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/* Skip any empty pages. */
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while (NEXTINDEX(h) == 0 && h->prevpg != P_INVALID) {
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pg = h->prevpg;
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mpool_put(t->bt_mp, h, 0);
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if ((h = mpool_get(t->bt_mp, pg, 0)) == NULL)
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return (RET_ERROR);
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}
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if (NEXTINDEX(h) == 0) {
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mpool_put(t->bt_mp, h, 0);
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return (RET_SPECIAL);
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}
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ep->page = h;
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ep->index = NEXTINDEX(h) - 1;
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break;
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}
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return (RET_SUCCESS);
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}
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/*
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* BT_SEQADVANCE -- Advance the sequential scan.
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*
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* Parameters:
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* t: tree
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* flags: R_NEXT, R_PREV
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*
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* Side effects:
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* Pins the page the new key/data record is on.
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*
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* Returns:
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* RET_ERROR, RET_SUCCESS or RET_SPECIAL if there's no next key.
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*/
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static int
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bt_seqadv(BTREE *t, EPG *e, int flags)
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{
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EPGNO *c, delc;
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PAGE *h;
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indx_t index;
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pgno_t pg;
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/* Save the current cursor if going to delete it. */
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c = &t->bt_bcursor;
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if (ISSET(t, B_DELCRSR))
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delc = *c;
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if ((h = mpool_get(t->bt_mp, c->pgno, 0)) == NULL)
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return (RET_ERROR);
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/*
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* Find the next/previous record in the tree and point the cursor at it.
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* The cursor may not be moved until a new key has been found.
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*/
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index = c->index;
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switch(flags) {
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case R_NEXT: /* Next record. */
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if (++index == NEXTINDEX(h)) {
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do {
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pg = h->nextpg;
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mpool_put(t->bt_mp, h, 0);
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if (pg == P_INVALID)
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return (RET_SPECIAL);
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if ((h = mpool_get(t->bt_mp, pg, 0)) == NULL)
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return (RET_ERROR);
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} while (NEXTINDEX(h) == 0);
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index = 0;
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}
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break;
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case R_PREV: /* Previous record. */
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if (index-- == 0) {
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do {
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pg = h->prevpg;
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mpool_put(t->bt_mp, h, 0);
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if (pg == P_INVALID)
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return (RET_SPECIAL);
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if ((h = mpool_get(t->bt_mp, pg, 0)) == NULL)
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return (RET_ERROR);
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} while (NEXTINDEX(h) == 0);
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index = NEXTINDEX(h) - 1;
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}
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break;
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}
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e->page = h;
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e->index = index;
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/*
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* Delete any already deleted record that we've been saving because the
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* cursor pointed to it. This could cause the new index to be shifted
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* down by one if the record we're deleting is on the same page and has
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* a larger index.
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*/
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if (ISSET(t, B_DELCRSR)) {
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CLR(t, B_DELCRSR); /* Don't try twice. */
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if (c->pgno == delc.pgno && c->index > delc.index)
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--c->index;
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if (__bt_crsrdel(t, &delc))
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return (RET_ERROR);
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}
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return (RET_SUCCESS);
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}
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/*
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* __BT_CRSRDEL -- Delete the record referenced by the cursor.
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*
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* Parameters:
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* t: tree
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*
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* Returns:
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* RET_ERROR, RET_SUCCESS
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*/
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int
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__bt_crsrdel(BTREE *t, EPGNO *c)
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{
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PAGE *h;
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int status;
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CLR(t, B_DELCRSR); /* Don't try twice. */
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if ((h = mpool_get(t->bt_mp, c->pgno, 0)) == NULL)
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return (RET_ERROR);
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status = __bt_dleaf(t, h, c->index);
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mpool_put(t->bt_mp, h, MPOOL_DIRTY);
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return (status);
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}
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