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e16a7d8f3b
`et` means `expandtab`. ```sh rg 'vi: .* :vi' -l -0 | \ xargs -0 sed -i '' 's/vi: \(.*\) et\(.*\) :vi/vi: \1 xoet\2:vi/' rg 'vi: .* :vi' -l -0 | \ xargs -0 sed -i '' 's/vi: \(.*\)noet\(.*\):vi/vi: \1et\2 :vi/' rg 'vi: .* :vi' -l -0 | \ xargs -0 sed -i '' 's/vi: \(.*\)xoet\(.*\):vi/vi: \1noet\2:vi/' ```
78 lines
3 KiB
C
78 lines
3 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│ vi: set et ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi │
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2020 Justine Alexandra Roberts Tunney │
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│ │
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│ Permission to use, copy, modify, and/or distribute this software for │
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│ any purpose with or without fee is hereby granted, provided that the │
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│ above 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 THE AUTHOR DISCLAIMS ALL │
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│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
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│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
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│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
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│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
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│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
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│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
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│ PERFORMANCE OF THIS SOFTWARE. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/dns/dns.h"
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#include "libc/macros.internal.h"
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#include "libc/str/str.h"
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forceinline void FindDnsLabel(const char *A, size_t *i, size_t *n) {
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while (*i) {
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if (A[*i - 1] == '.') {
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if (*i == *n) {
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--(*n);
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} else {
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break;
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}
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}
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--(*i);
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}
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}
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/**
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* Compares DNS hostnames in reverse lexicographical asciibetical order.
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* @return <0, 0, or >0
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* @see test/libc/dns/comparednsnames_test.c (the code that matters)
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*/
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int CompareDnsNames(const char *A, const char *B) {
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int res;
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bool first;
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size_t n, m, i, j;
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if (A == B) return 0;
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n = strlen(A);
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m = strlen(B);
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if (!n || !m || ((A[n - 1] == '.') ^ (B[m - 1] == '.'))) {
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if (n && m && A[n - 1] == '.' && strchr(B, '.')) {
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--m;
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} else if (n && m && B[m - 1] == '.' && strchr(A, '.')) {
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--n;
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} else {
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return A[n ? n - 1 : 0] - B[m ? m - 1 : 0];
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}
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}
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i = n;
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j = m;
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first = true;
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for (;;) {
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FindDnsLabel(A, &i, &n);
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FindDnsLabel(B, &j, &m);
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if (first) {
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first = false;
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if (!i && j) return 1;
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if (!j && i) return -1;
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}
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if ((res = strncasecmp(&A[i], &B[j], MIN(n - i + 1, m - j + 1)))) {
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return res;
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}
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if (!i || !j) {
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return i - j;
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}
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n = i;
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m = j;
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}
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}
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