46 lines
2.5 KiB
C
46 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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│ This program is free software; you can redistribute it and/or modify │
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│ it under the terms of the GNU General Public License as published by │
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│ the Free Software Foundation; version 2 of the License. │
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│ │
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│ This program is distributed in the hope that it will be useful, but │
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│ WITHOUT ANY WARRANTY; without even the implied warranty of │
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│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU │
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│ General Public License for more details. │
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│ │
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│ You should have received a copy of the GNU General Public License │
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│ along with this program; if not, write to the Free Software │
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│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA │
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│ 02110-1301 USA │
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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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