diff options
Diffstat (limited to 'db/btree/bt_seq.c')
| -rw-r--r-- | db/btree/bt_seq.c | 460 |
1 files changed, 0 insertions, 460 deletions
diff --git a/db/btree/bt_seq.c b/db/btree/bt_seq.c deleted file mode 100644 index 90f896036f..0000000000 --- a/db/btree/bt_seq.c +++ /dev/null @@ -1,460 +0,0 @@ -/*- - * 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[] = "@(#)bt_seq.c 8.7 (Berkeley) 7/20/94"; -#endif /* LIBC_SCCS and not lint */ - -#include <sys/types.h> - -#include <errno.h> -#include <stddef.h> -#include <stdio.h> -#include <stdlib.h> - -#include <db.h> -#include "btree.h" - -static int __bt_first __P((BTREE *, const DBT *, EPG *, int *)); -static int __bt_seqadv __P((BTREE *, EPG *, int)); -static int __bt_seqset __P((BTREE *, EPG *, DBT *, int)); - -/* - * Sequential scan support. - * - * The tree can be scanned sequentially, starting from either end of the - * tree or from any specific key. A scan request before any scanning is - * done is initialized as starting from the least node. - */ - -/* - * __bt_seq -- - * Btree sequential scan interface. - * - * Parameters: - * dbp: pointer to access method - * key: key for positioning and return value - * data: data return value - * flags: R_CURSOR, R_FIRST, R_LAST, R_NEXT, R_PREV. - * - * Returns: - * RET_ERROR, RET_SUCCESS or RET_SPECIAL if there's no next key. - */ -int -__bt_seq(dbp, key, data, flags) - const DB *dbp; - DBT *key, *data; - u_int flags; -{ - BTREE *t; - EPG e; - 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; - } - - /* - * If scan uninitialized as yet, or starting at a specific record, set - * the scan to a specific key. Both __bt_seqset and __bt_seqadv pin - * the page the cursor references if they're successful. - */ - switch (flags) { - case R_NEXT: - case R_PREV: - if (F_ISSET(&t->bt_cursor, CURS_INIT)) { - status = __bt_seqadv(t, &e, flags); - break; - } - /* FALLTHROUGH */ - case R_FIRST: - case R_LAST: - case R_CURSOR: - status = __bt_seqset(t, &e, key, flags); - break; - default: - errno = EINVAL; - return (RET_ERROR); - } - - if (status == RET_SUCCESS) { - __bt_setcur(t, e.page->pgno, e.index); - - status = - __bt_ret(t, &e, key, &t->bt_rkey, data, &t->bt_rdata, 0); - - /* - * If the user is doing concurrent access, we copied the - * key/data, toss the page. - */ - if (F_ISSET(t, B_DB_LOCK)) - mpool_put(t->bt_mp, e.page, 0); - else - t->bt_pinned = e.page; - } - return (status); -} - -/* - * __bt_seqset -- - * Set the sequential scan to a specific key. - * - * Parameters: - * t: tree - * ep: storage for returned key - * key: key for initial scan position - * flags: R_CURSOR, R_FIRST, R_LAST, R_NEXT, R_PREV - * - * Side effects: - * Pins the page the cursor references. - * - * Returns: - * RET_ERROR, RET_SUCCESS or RET_SPECIAL if there's no next key. - */ -static int -__bt_seqset(t, ep, key, flags) - BTREE *t; - EPG *ep; - DBT *key; - int flags; -{ - PAGE *h; - pgno_t pg; - int exact; - - /* - * Find the first, last or specific key in the tree and point the - * cursor at it. The cursor may not be moved until a new key has - * been found. - */ - switch (flags) { - case R_CURSOR: /* Keyed scan. */ - /* - * Find the first instance of the key or the smallest key - * which is greater than or equal to the specified key. - */ - if (key->data == NULL || key->size == 0) { - errno = EINVAL; - return (RET_ERROR); - } - return (__bt_first(t, key, ep, &exact)); - case R_FIRST: /* First record. */ - case R_NEXT: - /* Walk down the left-hand side of the tree. */ - for (pg = P_ROOT;;) { - if ((h = mpool_get(t->bt_mp, pg, 0)) == NULL) - return (RET_ERROR); - - /* Check for an empty tree. */ - if (NEXTINDEX(h) == 0) { - mpool_put(t->bt_mp, h, 0); - return (RET_SPECIAL); - } - - if (h->flags & (P_BLEAF | P_RLEAF)) - break; - pg = GETBINTERNAL(h, 0)->pgno; - mpool_put(t->bt_mp, h, 0); - } - ep->page = h; - ep->index = 0; - break; - case R_LAST: /* Last record. */ - case R_PREV: - /* Walk down the right-hand side of the tree. */ - for (pg = P_ROOT;;) { - if ((h = mpool_get(t->bt_mp, pg, 0)) == NULL) - return (RET_ERROR); - - /* Check for an empty tree. */ - if (NEXTINDEX(h) == 0) { - mpool_put(t->bt_mp, h, 0); - return (RET_SPECIAL); - } - - if (h->flags & (P_BLEAF | P_RLEAF)) - break; - pg = GETBINTERNAL(h, NEXTINDEX(h) - 1)->pgno; - mpool_put(t->bt_mp, h, 0); - } - - ep->page = h; - ep->index = NEXTINDEX(h) - 1; - break; - } - return (RET_SUCCESS); -} - -/* - * __bt_seqadvance -- - * Advance the sequential scan. - * - * Parameters: - * t: tree - * flags: R_NEXT, R_PREV - * - * Side effects: - * Pins the page the new key/data record is on. - * - * Returns: - * RET_ERROR, RET_SUCCESS or RET_SPECIAL if there's no next key. - */ -static int -__bt_seqadv(t, ep, flags) - BTREE *t; - EPG *ep; - int flags; -{ - CURSOR *c; - PAGE *h; - indx_t index; - pgno_t pg; - int exact; - - /* - * There are a couple of states that we can be in. The cursor has - * been initialized by the time we get here, but that's all we know. - */ - c = &t->bt_cursor; - - /* - * The cursor was deleted where there weren't any duplicate records, - * so the key was saved. Find out where that key would go in the - * current tree. It doesn't matter if the returned key is an exact - * match or not -- if it's an exact match, the record was added after - * the delete so we can just return it. If not, as long as there's - * a record there, return it. - */ - if (F_ISSET(c, CURS_ACQUIRE)) - return (__bt_first(t, &c->key, ep, &exact)); - - /* Get the page referenced by the cursor. */ - if ((h = mpool_get(t->bt_mp, c->pg.pgno, 0)) == NULL) - return (RET_ERROR); - - /* - * Find the next/previous record in the tree and point the cursor at - * it. The cursor may not be moved until a new key has been found. - */ - switch (flags) { - case R_NEXT: /* Next record. */ - /* - * The cursor was deleted in duplicate records, and moved - * forward to a record that has yet to be returned. Clear - * that flag, and return the record. - */ - if (F_ISSET(c, CURS_AFTER)) - goto usecurrent; - index = c->pg.index; - if (++index == NEXTINDEX(h)) { - pg = h->nextpg; - mpool_put(t->bt_mp, h, 0); - if (pg == P_INVALID) - return (RET_SPECIAL); - if ((h = mpool_get(t->bt_mp, pg, 0)) == NULL) - return (RET_ERROR); - index = 0; - } - break; - case R_PREV: /* Previous record. */ - /* - * The cursor was deleted in duplicate records, and moved - * backward to a record that has yet to be returned. Clear - * that flag, and return the record. - */ - if (F_ISSET(c, CURS_BEFORE)) { -usecurrent: F_CLR(c, CURS_AFTER | CURS_BEFORE); - ep->page = h; - ep->index = c->pg.index; - return (RET_SUCCESS); - } - index = c->pg.index; - if (index == 0) { - pg = h->prevpg; - mpool_put(t->bt_mp, h, 0); - if (pg == P_INVALID) - return (RET_SPECIAL); - if ((h = mpool_get(t->bt_mp, pg, 0)) == NULL) - return (RET_ERROR); - index = NEXTINDEX(h) - 1; - } else - --index; - break; - } - - ep->page = h; - ep->index = index; - return (RET_SUCCESS); -} - -/* - * __bt_first -- - * Find the first entry. - * - * Parameters: - * t: the tree - * key: the key - * erval: return EPG - * exactp: pointer to exact match flag - * - * Returns: - * The first entry in the tree greater than or equal to key, - * or RET_SPECIAL if no such key exists. - */ -static int -__bt_first(t, key, erval, exactp) - BTREE *t; - const DBT *key; - EPG *erval; - int *exactp; -{ - PAGE *h; - EPG *ep, save; - pgno_t pg; - - /* - * Find any matching record; __bt_search pins the page. - * - * If it's an exact match and duplicates are possible, walk backwards - * in the tree until we find the first one. Otherwise, make sure it's - * a valid key (__bt_search may return an index just past the end of a - * page) and return it. - */ - if ((ep = __bt_search(t, key, exactp)) == NULL) - return (RET_SPECIAL); - if (*exactp) { - if (F_ISSET(t, B_NODUPS)) { - *erval = *ep; - return (RET_SUCCESS); - } - - /* - * Walk backwards, as long as the entry matches and there are - * keys left in the tree. Save a copy of each match in case - * we go too far. - */ - save = *ep; - h = ep->page; - do { - if (save.page->pgno != ep->page->pgno) { - mpool_put(t->bt_mp, save.page, 0); - save = *ep; - } else - save.index = ep->index; - - /* - * Don't unpin the page the last (or original) match - * was on, but make sure it's unpinned if an error - * occurs. - */ - if (ep->index == 0) { - if (h->prevpg == P_INVALID) - break; - if (h->pgno != save.page->pgno) - mpool_put(t->bt_mp, h, 0); - if ((h = mpool_get(t->bt_mp, - h->prevpg, 0)) == NULL) { - if (h->pgno == save.page->pgno) - mpool_put(t->bt_mp, - save.page, 0); - return (RET_ERROR); - } - ep->page = h; - ep->index = NEXTINDEX(h); - } - --ep->index; - } while (__bt_cmp(t, key, ep) == 0); - - /* - * Reach here with the last page that was looked at pinned, - * which may or may not be the same as the last (or original) - * match page. If it's not useful, release it. - */ - if (h->pgno != save.page->pgno) - mpool_put(t->bt_mp, h, 0); - - *erval = save; - return (RET_SUCCESS); - } - - /* If at the end of a page, find the next entry. */ - if (ep->index == NEXTINDEX(ep->page)) { - h = ep->page; - pg = h->nextpg; - mpool_put(t->bt_mp, h, 0); - if (pg == P_INVALID) - return (RET_SPECIAL); - if ((h = mpool_get(t->bt_mp, pg, 0)) == NULL) - return (RET_ERROR); - ep->index = 0; - ep->page = h; - } - *erval = *ep; - return (RET_SUCCESS); -} - -/* - * __bt_setcur -- - * Set the cursor to an entry in the tree. - * - * Parameters: - * t: the tree - * pgno: page number - * index: page index - */ -void -__bt_setcur(t, pgno, index) - BTREE *t; - pgno_t pgno; - u_int index; -{ - /* Lose any already deleted key. */ - if (t->bt_cursor.key.data != NULL) { - free(t->bt_cursor.key.data); - t->bt_cursor.key.size = 0; - t->bt_cursor.key.data = NULL; - } - F_CLR(&t->bt_cursor, CURS_ACQUIRE | CURS_AFTER | CURS_BEFORE); - - /* Update the cursor. */ - t->bt_cursor.pg.pgno = pgno; - t->bt_cursor.pg.index = index; - F_SET(&t->bt_cursor, CURS_INIT); -} |