1 /*- 2 * Copyright (c) 1990, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34 #if defined(LIBC_SCCS) && !defined(lint) 35 static char sccsid[] = "@(#)bt_page.c 8.2 (Berkeley) 2/21/94"; 36 #endif /* LIBC_SCCS and not lint */ 37 38 #include <sys/types.h> 39 40 #include <stdio.h> 41 42 #include <db.h> 43 #include "btree.h" 44 45 /* 46 * __BT_FREE -- Put a page on the freelist. 47 * 48 * Parameters: 49 * t: tree 50 * h: page to free 51 * 52 * Returns: 53 * RET_ERROR, RET_SUCCESS 54 */ 55 int 56 __bt_free(t, h) 57 BTREE *t; 58 PAGE *h; 59 { 60 /* Insert the page at the start of the free list. */ 61 h->prevpg = P_INVALID; 62 h->nextpg = t->bt_free; 63 t->bt_free = h->pgno; 64 65 /* Make sure the page gets written back. */ 66 return (mpool_put(t->bt_mp, h, MPOOL_DIRTY)); 67 } 68 69 /* 70 * __BT_NEW -- Get a new page, preferably from the freelist. 71 * 72 * Parameters: 73 * t: tree 74 * npg: storage for page number. 75 * 76 * Returns: 77 * Pointer to a page, NULL on error. 78 */ 79 PAGE * 80 __bt_new(t, npg) 81 BTREE *t; 82 pgno_t *npg; 83 { 84 PAGE *h; 85 86 if (t->bt_free != P_INVALID && 87 (h = mpool_get(t->bt_mp, t->bt_free, 0)) != NULL) { 88 *npg = t->bt_free; 89 t->bt_free = h->nextpg; 90 return (h); 91 } 92 return (mpool_new(t->bt_mp, npg)); 93 } 94