1 /* 2 * Copyright (c) 2008 The DragonFly Project. All rights reserved. 3 * 4 * This code is derived from software contributed to The DragonFly Project 5 * by Matthew Dillon <dillon@backplane.com> 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in 15 * the documentation and/or other materials provided with the 16 * distribution. 17 * 3. Neither the name of The DragonFly Project nor the names of its 18 * contributors may be used to endorse or promote products derived 19 * from this software without specific, prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 24 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 25 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 26 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, 27 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 28 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 29 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 30 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 31 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * $DragonFly: src/sbin/hammer/misc.c,v 1.2 2008/01/21 00:03:31 dillon Exp $ 35 */ 36 37 #include "hammer.h" 38 39 /* 40 * (taken from /usr/src/sys/vfs/hammer/hammer_btree.c) 41 * 42 * Compare two B-Tree elements, return -N, 0, or +N (e.g. similar to strcmp). 43 * 44 * Note that for this particular function a return value of -1, 0, or +1 45 * can denote a match if delete_tid is otherwise discounted. A delete_tid 46 * of zero is considered to be 'infinity' in comparisons. 47 * 48 * See also hammer_rec_rb_compare() and hammer_rec_cmp() in hammer_object.c. 49 */ 50 int 51 hammer_btree_cmp(hammer_base_elm_t key1, hammer_base_elm_t key2) 52 { 53 if (key1->obj_id < key2->obj_id) 54 return(-4); 55 if (key1->obj_id > key2->obj_id) 56 return(4); 57 58 if (key1->rec_type < key2->rec_type) 59 return(-3); 60 if (key1->rec_type > key2->rec_type) 61 return(3); 62 63 if (key1->key < key2->key) 64 return(-2); 65 if (key1->key > key2->key) 66 return(2); 67 68 /* 69 * A delete_tid of zero indicates a record which has not been 70 * deleted yet and must be considered to have a value of positive 71 * infinity. 72 */ 73 if (key1->delete_tid == 0) { 74 if (key2->delete_tid == 0) 75 return(0); 76 return(1); 77 } 78 if (key2->delete_tid == 0) 79 return(-1); 80 if (key1->delete_tid < key2->delete_tid) 81 return(-1); 82 if (key1->delete_tid > key2->delete_tid) 83 return(1); 84 return(0); 85 } 86 87