diff options
Diffstat (limited to 'trunk/main/db1-ast/btree/bt_page.c')
| -rw-r--r-- | trunk/main/db1-ast/btree/bt_page.c | 100 |
1 files changed, 100 insertions, 0 deletions
diff --git a/trunk/main/db1-ast/btree/bt_page.c b/trunk/main/db1-ast/btree/bt_page.c new file mode 100644 index 000000000..e77a1d6b5 --- /dev/null +++ b/trunk/main/db1-ast/btree/bt_page.c @@ -0,0 +1,100 @@ +/*- + * Copyright (c) 1990, 1993, 1994 + * 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. + */ + +#if defined(LIBC_SCCS) && !defined(lint) +static char sccsid[] = "@(#)bt_page.c 8.3 (Berkeley) 7/14/94"; +#endif /* LIBC_SCCS and not lint */ + +#include <sys/types.h> + +#include <stdio.h> + +#include "../include/db.h" +#include "btree.h" + +/* + * __bt_free -- + * Put a page on the freelist. + * + * Parameters: + * t: tree + * h: page to free + * + * Returns: + * RET_ERROR, RET_SUCCESS + * + * Side-effect: + * mpool_put's the page. + */ +int +__bt_free(t, h) + BTREE *t; + PAGE *h; +{ + /* Insert the page at the head of the free list. */ + h->prevpg = P_INVALID; + h->nextpg = t->bt_free; + t->bt_free = h->pgno; + F_SET(t, B_METADIRTY); + + /* Make sure the page gets written back. */ + return (mpool_put(t->bt_mp, h, MPOOL_DIRTY)); +} + +/* + * __bt_new -- + * Get a new page, preferably from the freelist. + * + * Parameters: + * t: tree + * npg: storage for page number. + * + * Returns: + * Pointer to a page, NULL on error. + */ +PAGE * +__bt_new(t, npg) + BTREE *t; + pgno_t *npg; +{ + PAGE *h; + + if (t->bt_free != P_INVALID && + (h = mpool_get(t->bt_mp, t->bt_free, 0)) != NULL) { + *npg = t->bt_free; + t->bt_free = h->nextpg; + F_SET(t, B_METADIRTY); + return (h); + } + return (mpool_new(t->bt_mp, npg)); +} |