diff options
Diffstat (limited to 'db2/btree/bt_search.c')
| -rw-r--r-- | db2/btree/bt_search.c | 369 |
1 files changed, 0 insertions, 369 deletions
diff --git a/db2/btree/bt_search.c b/db2/btree/bt_search.c deleted file mode 100644 index 1f439a4261..0000000000 --- a/db2/btree/bt_search.c +++ /dev/null @@ -1,369 +0,0 @@ -/*- - * See the file LICENSE for redistribution information. - * - * Copyright (c) 1996, 1997, 1998 - * Sleepycat Software. All rights reserved. - */ -/* - * Copyright (c) 1990, 1993, 1994, 1995, 1996 - * Keith Bostic. All rights reserved. - */ -/* - * Copyright (c) 1990, 1993, 1994, 1995 - * 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. - */ - -#include "config.h" - -#ifndef lint -static const char sccsid[] = "@(#)bt_search.c 10.25 (Sleepycat) 12/16/98"; -#endif /* not lint */ - -#ifndef NO_SYSTEM_INCLUDES -#include <sys/types.h> - -#include <errno.h> -#include <string.h> -#endif - -#include "db_int.h" -#include "db_page.h" -#include "btree.h" - -/* - * __bam_search -- - * Search a btree for a key. - * - * PUBLIC: int __bam_search __P((DBC *, - * PUBLIC: const DBT *, u_int32_t, int, db_recno_t *, int *)); - */ -int -__bam_search(dbc, key, flags, stop, recnop, exactp) - DBC *dbc; - const DBT *key; - u_int32_t flags; - int stop, *exactp; - db_recno_t *recnop; -{ - BTREE *t; - CURSOR *cp; - DB *dbp; - DB_LOCK lock; - PAGE *h; - db_indx_t base, i, indx, lim; - db_pgno_t pg; - db_recno_t recno; - int cmp, jump, ret, stack; - - dbp = dbc->dbp; - cp = dbc->internal; - t = dbp->internal; - recno = 0; - - BT_STK_CLR(cp); - - /* - * There are several ways we search a btree tree. The flags argument - * specifies if we're acquiring read or write locks, if we position - * to the first or last item in a set of duplicates, if we return - * deleted items, and if we are locking pairs of pages. In addition, - * if we're modifying record numbers, we have to lock the entire tree - * regardless. 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; - stack = F_ISSET(dbp, DB_BT_RECNUM) && LF_ISSET(S_STACK); - if ((ret = __bam_lget(dbc, - 0, pg, stack ? DB_LOCK_WRITE : DB_LOCK_READ, &lock)) != 0) - return (ret); - if ((ret = memp_fget(dbp->mpf, &pg, 0, &h)) != 0) { - (void)__BT_LPUT(dbc, lock); - return (ret); - } - - /* - * Decide if we need to save this page; if we do, write lock it. - * We deliberately don't lock-couple on this call. If the tree - * is tiny, i.e., one page, and two threads are busily updating - * the root page, we're almost guaranteed deadlocks galore, as - * each one gets a read lock and then blocks the other's attempt - * for a write lock. - */ - if (!stack && - ((LF_ISSET(S_PARENT) && (u_int8_t)(stop + 1) >= h->level) || - (LF_ISSET(S_WRITE) && h->level == LEAFLEVEL))) { - (void)memp_fput(dbp->mpf, h, 0); - (void)__BT_LPUT(dbc, lock); - if ((ret = __bam_lget(dbc, 0, pg, DB_LOCK_WRITE, &lock)) != 0) - return (ret); - if ((ret = memp_fget(dbp->mpf, &pg, 0, &h)) != 0) { - (void)__BT_LPUT(dbc, lock); - return (ret); - } - stack = 1; - } - - for (;;) { - /* - * Do a binary search on the current page. If we're searching - * a leaf page, we have to manipulate the indices in groups of - * two. If we're searching an internal page, they're an index - * per page item. If we find an exact match on a leaf page, - * we're done. - */ - jump = TYPE(h) == P_LBTREE ? P_INDX : O_INDX; - for (base = 0, - lim = NUM_ENT(h) / (db_indx_t)jump; lim != 0; lim >>= 1) { - indx = base + ((lim >> 1) * jump); - if ((cmp = - __bam_cmp(dbp, key, h, indx, t->bt_compare)) == 0) { - if (TYPE(h) == P_LBTREE) - goto match; - goto next; - } - if (cmp > 0) { - base = indx + jump; - --lim; - } - } - - /* - * No match found. Base is the smallest index greater than - * key and may be zero or a last + O_INDX index. - * - * If it's a leaf page, return base as the "found" value. - * Delete only deletes exact matches. - */ - if (TYPE(h) == P_LBTREE) { - *exactp = 0; - - if (LF_ISSET(S_EXACT)) - goto notfound; - - /* - * !!! - * Possibly returning a deleted record -- DB_SET_RANGE, - * DB_KEYFIRST and DB_KEYLAST don't require an exact - * match, and we don't want to walk multiple pages here - * to find an undeleted record. This is handled in the - * __bam_c_search() routine. - */ - BT_STK_ENTER(cp, h, base, lock, ret); - return (ret); - } - - /* - * If it's not a leaf page, record the internal page (which is - * a parent page for the key). Decrement the base by 1 if it's - * non-zero so that if a split later occurs, the inserted page - * will be to the right of the saved page. - */ - indx = base > 0 ? base - O_INDX : base; - - /* - * If we're trying to calculate the record number, sum up - * all the record numbers on this page up to the indx point. - */ - if (recnop != NULL) - for (i = 0; i < indx; ++i) - recno += GET_BINTERNAL(h, i)->nrecs; - -next: pg = GET_BINTERNAL(h, indx)->pgno; - if (stack) { - /* Return if this is the lowest page wanted. */ - if (LF_ISSET(S_PARENT) && stop == h->level) { - BT_STK_ENTER(cp, h, indx, lock, ret); - return (ret); - } - BT_STK_PUSH(cp, h, indx, lock, ret); - if (ret != 0) - goto err; - - if ((ret = - __bam_lget(dbc, 0, pg, DB_LOCK_WRITE, &lock)) != 0) - goto err; - } else { - /* - * Decide if we want to return a reference to the next - * page in the return stack. If so, lock it and never - * unlock it. - */ - if ((LF_ISSET(S_PARENT) && - (u_int8_t)(stop + 1) >= (u_int8_t)(h->level - 1)) || - (h->level - 1) == LEAFLEVEL) - stack = 1; - - (void)memp_fput(dbp->mpf, h, 0); - - if ((ret = - __bam_lget(dbc, 1, pg, stack && LF_ISSET(S_WRITE) ? - DB_LOCK_WRITE : DB_LOCK_READ, &lock)) != 0) - goto err; - } - if ((ret = memp_fget(dbp->mpf, &pg, 0, &h)) != 0) - goto err; - } - /* NOTREACHED */ - -match: *exactp = 1; - - /* - * If we're trying to calculate the record number, add in the - * offset on this page and correct for the fact that records - * in the tree are 0-based. - */ - if (recnop != NULL) - *recnop = recno + (indx / P_INDX) + 1; - - /* - * If we got here, we know that we have a btree leaf page. - * - * If there are duplicates, go to the first/last one. This is - * safe because we know that we're not going to leave the page, - * all duplicate sets that are not on overflow pages exist on a - * single leaf page. - */ - if (LF_ISSET(S_DUPLAST)) - while (indx < (db_indx_t)(NUM_ENT(h) - P_INDX) && - h->inp[indx] == h->inp[indx + P_INDX]) - indx += P_INDX; - else - while (indx > 0 && - h->inp[indx] == h->inp[indx - P_INDX]) - indx -= P_INDX; - - /* - * Now check if we are allowed to return deleted items; if not - * find the next (or previous) non-deleted item. - */ - if (LF_ISSET(S_DELNO)) { - if (LF_ISSET(S_DUPLAST)) - while (B_DISSET(GET_BKEYDATA(h, indx + O_INDX)->type) && - indx > 0 && - h->inp[indx] == h->inp[indx - P_INDX]) - indx -= P_INDX; - else - while (B_DISSET(GET_BKEYDATA(h, indx + O_INDX)->type) && - indx < (db_indx_t)(NUM_ENT(h) - P_INDX) && - h->inp[indx] == h->inp[indx + P_INDX]) - indx += P_INDX; - - if (B_DISSET(GET_BKEYDATA(h, indx + O_INDX)->type)) - goto notfound; - } - - BT_STK_ENTER(cp, h, indx, lock, ret); - return (ret); - -notfound: - (void)memp_fput(dbp->mpf, h, 0); - (void)__BT_LPUT(dbc, lock); - ret = DB_NOTFOUND; - -err: if (cp->csp > cp->sp) { - BT_STK_POP(cp); - __bam_stkrel(dbc, 0); - } - return (ret); -} - -/* - * __bam_stkrel -- - * Release all pages currently held in the stack. - * - * PUBLIC: int __bam_stkrel __P((DBC *, int)); - */ -int -__bam_stkrel(dbc, nolocks) - DBC *dbc; - int nolocks; -{ - CURSOR *cp; - DB *dbp; - EPG *epg; - - dbp = dbc->dbp; - cp = dbc->internal; - - /* Release inner pages first. */ - for (epg = cp->sp; epg <= cp->csp; ++epg) { - if (epg->page != NULL) - (void)memp_fput(dbp->mpf, epg->page, 0); - if (epg->lock != LOCK_INVALID) { - if (nolocks) - (void)__BT_LPUT(dbc, epg->lock); - else - (void)__BT_TLPUT(dbc, epg->lock); - } - } - - /* Clear the stack, all pages have been released. */ - BT_STK_CLR(cp); - - return (0); -} - -/* - * __bam_stkgrow -- - * Grow the stack. - * - * PUBLIC: int __bam_stkgrow __P((CURSOR *)); - */ -int -__bam_stkgrow(cp) - CURSOR *cp; -{ - EPG *p; - size_t entries; - int ret; - - entries = cp->esp - cp->sp; - - if ((ret = __os_calloc(entries * 2, sizeof(EPG), &p)) != 0) - return (ret); - memcpy(p, cp->sp, entries * sizeof(EPG)); - if (cp->sp != cp->stack) - __os_free(cp->sp, entries * sizeof(EPG)); - cp->sp = p; - cp->csp = p + entries; - cp->esp = p + entries * 2; - return (0); -} |