1 /*- 2 * Copyright (c) 1990, 1993, 1994 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 8.3 (Berkeley) 7/14/94"; 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 -- 47 * Put a page on the freelist. 48 * 49 * Parameters: 50 * t: tree 51 * h: page to free 52 * 53 * Returns: 54 * RET_ERROR, RET_SUCCESS 55 * 56 * Side-effect: 57 * mpool_put's the page. 58 */ 59 int 60 __bt_free(t, h) 61 BTREE *t; 62 PAGE *h; 63 { 64 /* Insert the page at the head of the free list. */ 65 h->prevpg = P_INVALID; 66 h->nextpg = t->bt_free; 67 t->bt_free = h->pgno; 68 69 /* Make sure the page gets written back. */ 70 return (mpool_put(t->bt_mp, h, MPOOL_DIRTY)); 71 } 72 73 /* 74 * __bt_new -- 75 * Get a new page, preferably from the freelist. 76 * 77 * Parameters: 78 * t: tree 79 * npg: storage for page number. 80 * 81 * Returns: 82 * Pointer to a page, NULL on error. 83 */ 84 PAGE * 85 __bt_new(t, npg) 86 BTREE *t; 87 pgno_t *npg; 88 { 89 PAGE *h; 90 91 if (t->bt_free != P_INVALID && 92 (h = mpool_get(t->bt_mp, t->bt_free, 0)) != NULL) { 93 *npg = t->bt_free; 94 t->bt_free = h->nextpg; 95 return (h); 96 } 97 return (mpool_new(t->bt_mp, npg)); 98 } 99