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