61 строка
1.6 KiB
C
61 строка
1.6 KiB
C
/*
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* Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
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* Copyright (c) 1996,1999 by Internet Software Consortium.
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
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* OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#ifndef HAVE_BITNCMP
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#include <sys/types.h>
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#include <string.h>
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#include <stdlib.h>
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#include "bitncmp.h"
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/*
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* int
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* bitncmp(l, r, n)
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* compare bit masks l and r, for n bits.
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* return:
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* -1, 1, or 0 in the libc tradition.
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* note:
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* network byte order assumed. this means 192.5.5.240/28 has
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* 0x11110000 in its fourth octet.
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* author:
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* Paul Vixie (ISC), June 1996
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*/
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int
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ares_bitncmp(const void *l, const void *r, int n) {
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unsigned int lb, rb;
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int x, b;
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b = n / 8;
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x = memcmp(l, r, b);
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if (x)
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return (x);
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lb = ((const unsigned char *)l)[b];
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rb = ((const unsigned char *)r)[b];
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for (b = n % 8; b > 0; b--) {
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if ((lb & 0x80) != (rb & 0x80)) {
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if (lb & 0x80)
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return (1);
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return (-1);
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}
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lb <<= 1;
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rb <<= 1;
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}
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return (0);
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}
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#endif
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