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44 lines
2.4 KiB
C
44 lines
2.4 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/assert.h"
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#include "libc/bits/popcnt.h"
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#include "libc/stdio/stdio.h"
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#include "libc/testlib/testlib.h"
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unsigned naive(unsigned beg, unsigned end, unsigned size) {
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assert(end < size);
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assert(beg < size);
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assert(popcnt(size) == 1);
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if (beg == end) return size;
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if (end > beg) return end - beg;
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return (size - beg) + end;
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}
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unsigned fancy(unsigned beg, unsigned end, unsigned size) {
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return ((end - beg - 1) & (size - 1)) + 1;
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}
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TEST(favail, test) {
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unsigned i, j, n = 4;
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for (i = 0; i < n; ++i) {
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for (j = 0; j < n; ++j) {
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ASSERT_EQ(naive(i, j, n), fancy(i, j, n), "%u %u %u", i, j, n);
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}
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}
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}
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