1 /*- 2 * Copyright (c) 1990, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * %sccs.include.redist.c% 6 */ 7 8 #if defined(LIBC_SCCS) && !defined(lint) 9 static char sccsid[] = "@(#)bt_page.c 8.1 (Berkeley) 06/04/93"; 10 #endif /* LIBC_SCCS and not lint */ 11 12 #include <sys/types.h> 13 14 #define __DBINTERFACE_PRIVATE 15 #include <stdio.h> 16 17 #include <db.h> 18 #include "btree.h" 19 20 /* 21 * __BT_FREE -- Put a page on the freelist. 22 * 23 * Parameters: 24 * t: tree 25 * h: page to free 26 * 27 * Returns: 28 * RET_ERROR, RET_SUCCESS 29 */ 30 int 31 __bt_free(t, h) 32 BTREE *t; 33 PAGE *h; 34 { 35 /* Insert the page at the start of the free list. */ 36 h->prevpg = P_INVALID; 37 h->nextpg = t->bt_free; 38 t->bt_free = h->pgno; 39 40 /* Make sure the page gets written back. */ 41 return (mpool_put(t->bt_mp, h, MPOOL_DIRTY)); 42 } 43 44 /* 45 * __BT_NEW -- Get a new page, preferably from the freelist. 46 * 47 * Parameters: 48 * t: tree 49 * npg: storage for page number. 50 * 51 * Returns: 52 * Pointer to a page, NULL on error. 53 */ 54 PAGE * 55 __bt_new(t, npg) 56 BTREE *t; 57 pgno_t *npg; 58 { 59 PAGE *h; 60 61 if (t->bt_free != P_INVALID && 62 (h = mpool_get(t->bt_mp, t->bt_free, 0)) != NULL) { 63 *npg = t->bt_free; 64 t->bt_free = h->nextpg; 65 return (h); 66 } 67 return (mpool_new(t->bt_mp, npg)); 68 } 69