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42 lines
2.5 KiB
C
42 lines
2.5 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│vi: set net 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/mem/critbit0.h"
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#include "libc/mem/internal.h"
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#include "libc/str/str.h"
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/**
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* Returns non-zero iff 𝑢 ∈ 𝑡.
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* @param t tree
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* @param u NUL-terminated string
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* @note h/t djb and agl
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*/
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bool critbit0_contains(struct critbit0 *t, const char *u) {
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const unsigned char *ubytes = (void *)u;
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const size_t ulen = strlen(u);
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unsigned char *p = t->root;
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if (!p) return 0;
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while (1 & (intptr_t)p) {
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struct CritbitNode *q = (void *)(p - 1);
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unsigned char c = 0;
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if (q->byte < ulen) c = ubytes[q->byte];
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const int direction = (1 + (q->otherbits | c)) >> 8;
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p = q->child[direction];
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}
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return 0 == strcmp(u, (const char *)p);
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}
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