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-rw-r--r--db2/btree/bt_rsearch.c347
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diff --git a/db2/btree/bt_rsearch.c b/db2/btree/bt_rsearch.c
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+/*-
+ * See the file LICENSE for redistribution information.
+ *
+ * Copyright (c) 1996, 1997
+ * Sleepycat Software. All rights reserved.
+ */
+/*
+ * Copyright (c) 1990, 1993, 1994, 1995, 1996
+ * Keith Bostic. All rights reserved.
+ */
+/*
+ * 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.
+ */
+
+#include "config.h"
+
+#ifndef lint
+static const char sccsid[] = "@(#)bt_rsearch.c 10.8 (Sleepycat) 8/24/97";
+#endif /* not lint */
+
+#ifndef NO_SYSTEM_INCLUDES
+#include <sys/types.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#endif
+
+#include "db_int.h"
+#include "db_page.h"
+#include "btree.h"
+
+/*
+ * __bam_rsearch --
+ * Search a btree for a record number.
+ *
+ * PUBLIC: int __bam_rsearch __P((DB *, db_recno_t *, u_int, int, int *));
+ */
+int
+__bam_rsearch(dbp, recnop, flags, stop, exactp)
+ DB *dbp;
+ db_recno_t *recnop;
+ u_int flags;
+ int stop, *exactp;
+{
+ BINTERNAL *bi;
+ BTREE *t;
+ DB_LOCK lock;
+ PAGE *h;
+ RINTERNAL *ri;
+ db_indx_t indx, top;
+ db_pgno_t pg;
+ db_recno_t recno, total;
+ int isappend, ret, stack;
+
+ t = dbp->internal;
+
+ /*
+ * We test for groups of flags, S_APPEND is the only one that can be
+ * OR'd into the set. Clear it now so that the tests for equality
+ * will work.
+ */
+ if ((isappend = LF_ISSET(S_APPEND)) != 0)
+ LF_CLR(S_APPEND);
+
+ /*
+ * There are several ways we search a btree tree. The flags argument
+ * specifies if we're acquiring read or write locks and if we are
+ * locking pairs of pages. See btree.h for more details.
+ *
+ * If write-locking pages, we need to know whether or not to acquire a
+ * write lock on a page before getting it. This depends on how deep it
+ * is in tree, which we don't know until we acquire the root page. So,
+ * if we need to lock the root page we may have to upgrade it later,
+ * because we won't get the correct lock initially.
+ *
+ * Retrieve the root page.
+ */
+ pg = PGNO_ROOT;
+ if ((ret = __bam_lget(dbp, 0, PGNO_ROOT,
+ flags == S_INSERT || flags == S_DELETE ?
+ DB_LOCK_WRITE : DB_LOCK_READ, &lock)) != 0)
+ return (ret);
+ if ((ret = __bam_pget(dbp, &h, &pg, 0)) != 0) {
+ (void)__BT_LPUT(dbp, lock);
+ return (ret);
+ }
+ total = RE_NREC(h);
+
+ /*
+ * If appending to the tree, set the record number now -- we have the
+ * root page locked.
+ *
+ * Delete only deletes exact matches, read only returns exact matches.
+ * Note, this is different from __bam_search(), which returns non-exact
+ * matches for read.
+ *
+ * The record may not exist. We can only return the correct location
+ * for the record immediately after the last record in the tree, so do
+ * a fast check now.
+ */
+ if (isappend) {
+ *exactp = 0;
+ *recnop = recno = total + 1;
+ } else {
+ recno = *recnop;
+ if (recno <= total)
+ *exactp = 1;
+ else {
+ *exactp = 0;
+ if (flags == S_DELETE ||
+ flags == S_FIND || recno > total + 1) {
+ (void)memp_fput(dbp->mpf, h, 0);
+ (void)__BT_LPUT(dbp, lock);
+ return (DB_NOTFOUND);
+ }
+ }
+ }
+
+ /* Decide if we're building a stack based on the operation. */
+ BT_STK_CLR(t);
+ stack = flags == S_DELETE || flags == S_INSERT;
+
+ /*
+ * Decide if we need to save this page; if we do, write lock it, and
+ * start to build a stack.
+ */
+ if (LF_ISSET(S_PARENT) && (u_int8_t)(stop + 1) >= h->level) {
+ (void)memp_fput(dbp->mpf, h, 0);
+ if ((ret = __bam_lget(dbp, 1, pg, DB_LOCK_WRITE, &lock)) != 0)
+ return (ret);
+ if ((ret = __bam_pget(dbp, &h, &pg, 0)) != 0) {
+ (void)__BT_LPUT(dbp, lock);
+ return (ret);
+ }
+ stack = 1;
+ }
+
+ /* Records in the tree are 0-based, and record numbers are 1-based. */
+ --recno;
+
+ for (total = 0;;) {
+ switch (TYPE(h)) {
+ case P_LBTREE:
+ BT_STK_ENTER(t, h, (recno - total) * P_INDX, lock, ret);
+ return (ret);
+ case P_IBTREE:
+ for (indx = 0, top = NUM_ENT(h);;) {
+ bi = GET_BINTERNAL(h, indx);
+ if (++indx == top || total + bi->nrecs > recno)
+ break;
+ total += bi->nrecs;
+ }
+ pg = bi->pgno;
+ break;
+ case P_LRECNO:
+ BT_STK_ENTER(t, h, recno - total, lock, ret);
+ return (ret);
+ case P_IRECNO:
+ for (indx = 0, top = NUM_ENT(h);;) {
+ ri = GET_RINTERNAL(h, indx);
+ if (++indx == top || total + ri->nrecs > recno)
+ break;
+ total += ri->nrecs;
+ }
+ pg = ri->pgno;
+ break;
+ default:
+ return (__db_pgfmt(dbp, h->pgno));
+ }
+ --indx;
+
+ if (stack) {
+ /* Return if this is the lowest page wanted. */
+ if (LF_ISSET(S_PARENT) && stop == h->level) {
+ BT_STK_ENTER(t, h, indx, lock, ret);
+ return (ret);
+ }
+ BT_STK_PUSH(t, h, indx, lock, ret);
+ if (ret)
+ goto err;
+
+ if ((ret = __bam_lget(dbp, 0, pg,
+ LF_ISSET(S_WRITE) ? DB_LOCK_WRITE : DB_LOCK_READ,
+ &lock)) != 0)
+ goto err;
+ } else {
+ (void)memp_fput(dbp->mpf, h, 0);
+
+ /*
+ * Decide if we want to return a pointer to the next
+ * page in the stack. If we do, write lock it and
+ * never unlock it.
+ */
+ if (LF_ISSET(S_PARENT) &&
+ (u_int8_t)(stop + 1) >= (u_int8_t)(h->level - 1))
+ stack = 1;
+
+ if ((ret = __bam_lget(dbp, 1, pg,
+ LF_ISSET(S_WRITE) ? DB_LOCK_WRITE : DB_LOCK_READ,
+ &lock)) != 0)
+ goto err;
+ }
+
+ if ((ret = __bam_pget(dbp, &h, &pg, 0)) != 0)
+ goto err;
+ }
+ /* NOTREACHED */
+
+err: BT_STK_POP(t);
+ __bam_stkrel(dbp);
+ return (ret);
+}
+
+/*
+ * __bam_adjust --
+ * Adjust the tree after adding or deleting a record.
+ *
+ * PUBLIC: int __bam_adjust __P((DB *, BTREE *, int));
+ */
+int
+__bam_adjust(dbp, t, adjust)
+ DB *dbp;
+ BTREE *t;
+ int adjust;
+{
+ EPG *epg;
+ PAGE *h;
+ int ret;
+
+ /* Update the record counts for the tree. */
+ for (epg = t->bt_sp; epg <= t->bt_csp; ++epg) {
+ h = epg->page;
+ if (TYPE(h) == P_IBTREE || TYPE(h) == P_IRECNO) {
+ if (DB_LOGGING(dbp) &&
+ (ret = __bam_cadjust_log(dbp->dbenv->lg_info,
+ dbp->txn, &LSN(h), 0, dbp->log_fileid,
+ PGNO(h), &LSN(h), (u_int32_t)epg->indx,
+ (int32_t)adjust, 1)) != 0)
+ return (ret);
+
+ if (TYPE(h) == P_IBTREE)
+ GET_BINTERNAL(h, epg->indx)->nrecs += adjust;
+ else
+ GET_RINTERNAL(h, epg->indx)->nrecs += adjust;
+
+ if (PGNO(h) == PGNO_ROOT)
+ RE_NREC_ADJ(h, adjust);
+
+ if ((ret = memp_fset(dbp->mpf, h, DB_MPOOL_DIRTY)) != 0)
+ return (ret);
+ }
+ }
+ return (0);
+}
+
+/*
+ * __bam_nrecs --
+ * Return the number of records in the tree.
+ *
+ * PUBLIC: int __bam_nrecs __P((DB *, db_recno_t *));
+ */
+int
+__bam_nrecs(dbp, rep)
+ DB *dbp;
+ db_recno_t *rep;
+{
+ DB_LOCK lock;
+ PAGE *h;
+ db_pgno_t pgno;
+ int ret;
+
+ pgno = PGNO_ROOT;
+ if ((ret = __bam_lget(dbp, 0, pgno, DB_LOCK_READ, &lock)) != 0)
+ return (ret);
+ if ((ret = __bam_pget(dbp, &h, &pgno, 0)) != 0)
+ return (ret);
+
+ *rep = RE_NREC(h);
+
+ (void)memp_fput(dbp->mpf, h, 0);
+ (void)__BT_TLPUT(dbp, lock);
+
+ return (0);
+}
+
+/*
+ * __bam_total --
+ * Return the number of records below a page.
+ *
+ * PUBLIC: db_recno_t __bam_total __P((PAGE *));
+ */
+db_recno_t
+__bam_total(h)
+ PAGE *h;
+{
+ db_recno_t recs;
+ db_indx_t nxt, top;
+
+ switch (TYPE(h)) {
+ case P_LBTREE:
+ recs = NUM_ENT(h) / 2;
+ break;
+ case P_IBTREE:
+ for (recs = 0, nxt = 0, top = NUM_ENT(h); nxt < top; ++nxt)
+ recs += GET_BINTERNAL(h, nxt)->nrecs;
+ break;
+ case P_LRECNO:
+ recs = NUM_ENT(h);
+ break;
+ case P_IRECNO:
+ for (recs = 0, nxt = 0, top = NUM_ENT(h); nxt < top; ++nxt)
+ recs += GET_RINTERNAL(h, nxt)->nrecs;
+ break;
+ default:
+ abort();
+ }
+ return (recs);
+}
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