1 /* $NetBSD: bitncmp.c,v 1.1.1.1 2009/04/12 15:33:45 christos Exp $ */ 2 3 /* 4 * Copyright (C) 2004, 2005, 2008 Internet Systems Consortium, Inc. ("ISC") 5 * Copyright (C) 1996, 1999, 2001 Internet Software Consortium. 6 * 7 * Permission to use, copy, modify, and/or distribute this software for any 8 * purpose with or without fee is hereby granted, provided that the above 9 * copyright notice and this permission notice appear in all copies. 10 * 11 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH 12 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY 13 * AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT, 14 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM 15 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE 16 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR 17 * PERFORMANCE OF THIS SOFTWARE. 18 */ 19 20 #if defined(LIBC_SCCS) && !defined(lint) 21 static const char rcsid[] = "Id: bitncmp.c,v 1.5 2008/11/14 02:36:51 marka Exp"; 22 #endif 23 24 #include "port_before.h" 25 26 #include <sys/types.h> 27 28 #include <string.h> 29 30 #include "port_after.h" 31 32 #include <isc/misc.h> 33 34 /*% 35 * int 36 * bitncmp(l, r, n) 37 * compare bit masks l and r, for n bits. 38 * return: 39 * -1, 1, or 0 in the libc tradition. 40 * note: 41 * network byte order assumed. this means 192.5.5.240/28 has 42 * 0x11110000 in its fourth octet. 43 * author: 44 * Paul Vixie (ISC), June 1996 45 */ 46 int 47 bitncmp(const void *l, const void *r, int n) { 48 u_int lb, rb; 49 int x, b; 50 51 b = n / 8; 52 x = memcmp(l, r, b); 53 if (x || (n % 8) == 0) 54 return (x); 55 56 lb = ((const u_char *)l)[b]; 57 rb = ((const u_char *)r)[b]; 58 for (b = n % 8; b > 0; b--) { 59 if ((lb & 0x80) != (rb & 0x80)) { 60 if (lb & 0x80) 61 return (1); 62 return (-1); 63 } 64 lb <<= 1; 65 rb <<= 1; 66 } 67 return (0); 68 } 69 70 /*! \file */ 71