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 = "from: @(#)bt_page.c 8.1 (Berkeley) 6/4/93";*/ 36 static char *rcsid = "$Id: bt_page.c,v 1.3 1993/08/26 00:43:24 jtc Exp $"; 37 #endif /* LIBC_SCCS and not lint */ 38 39 #include <sys/types.h> 40 41 #define __DBINTERFACE_PRIVATE 42 #include <stdio.h> 43 44 #include <db.h> 45 #include "btree.h" 46 47 /* 48 * __BT_FREE -- Put a page on the freelist. 49 * 50 * Parameters: 51 * t: tree 52 * h: page to free 53 * 54 * Returns: 55 * RET_ERROR, RET_SUCCESS 56 */ 57 int 58 __bt_free(t, h) 59 BTREE *t; 60 PAGE *h; 61 { 62 /* Insert the page at the start of the free list. */ 63 h->prevpg = P_INVALID; 64 h->nextpg = t->bt_free; 65 t->bt_free = h->pgno; 66 67 /* Make sure the page gets written back. */ 68 return (mpool_put(t->bt_mp, h, MPOOL_DIRTY)); 69 } 70 71 /* 72 * __BT_NEW -- Get a new page, preferably from the freelist. 73 * 74 * Parameters: 75 * t: tree 76 * npg: storage for page number. 77 * 78 * Returns: 79 * Pointer to a page, NULL on error. 80 */ 81 PAGE * 82 __bt_new(t, npg) 83 BTREE *t; 84 pgno_t *npg; 85 { 86 PAGE *h; 87 88 if (t->bt_free != P_INVALID && 89 (h = mpool_get(t->bt_mp, t->bt_free, 0)) != NULL) { 90 *npg = t->bt_free; 91 t->bt_free = h->nextpg; 92 return (h); 93 } 94 return (mpool_new(t->bt_mp, npg)); 95 } 96