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