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/*
Copyright (C) 2015 William Hart
This file is part of FLINT.
FLINT is free software: you can redistribute it and/or modify it under
the terms of the GNU Lesser General Public License (LGPL) as published
by the Free Software Foundation; either version 3 of the License, or
(at your option) any later version. See <https://www.gnu.org/licenses/>.
*/
#include "test_helpers.h"
#include "ulong_extras.h"
ulong
n_revbin_naive(ulong n, ulong b)
{
ulong r = 0, i;
for (i = 0; i < b; i++)
{
r <<= 1;
r += (n & 1);
n >>= 1;
}
return r;
}
TEST_FUNCTION_START(n_revbin, state)
{
int i, result;
/* 0 bits */
for (i = 0; i < 10 * flint_test_multiplier(); i++)
{
ulong n, b, r;
n = n_randlimb(state);
b = 0;
r = n_revbin(n, b);
result = (r == 0);
if (!result)
TEST_FUNCTION_FAIL(
"b = %wu\n"
"n = %wx\n"
"r = %wx\n",
b, n, r);
}
/* at most 8 bits */
for (i = 0; i < 10 * flint_test_multiplier(); i++)
{
ulong n, b, d, r1, r2, mask;
for (b = 1; b <= 8; b++)
{
mask = ~((UWORD(1) << b) - UWORD(1)); /* 1111..11100..0 */
for (d = 0; d < UWORD(1) << b; d++)
{
/* garbage in top FLINT_BITS - b bits */
n = (n_randlimb(state) & mask);
n |= d;
r1 = n_revbin(n, b);
r2 = n_revbin_naive(d, b);
result = (r1 == r2);
if (!result)
TEST_FUNCTION_FAIL(
"b = %wu\n"
"n = %wx\n"
"d = %wx\n"
"r1 = %wx\n"
"r2 = %wx\n"
, b, n, d, r1, r2);
}
}
}
/* random number of bits */
for (i = 0; i < 100; i++)
{
ulong n, b, d, j, r1, r2, mask;
b = n_randint(state, FLINT_BITS) + 1;
/* 1111..11100..0 */
mask = b == FLINT_BITS ? UWORD(0) : ~((UWORD(1) << b) - UWORD(1));
for (j = 0; j < 1000 * flint_test_multiplier(); j++)
{
/* garbage in top FLINT_BITS - b bits */
n = (n_randlimb(state) & mask);
d = n_randbits(state, n_randint(state, b) + 1);
n |= d;
r1 = n_revbin(n, b);
r2 = n_revbin_naive(d, b);
result = (r1 == r2);
if (!result)
TEST_FUNCTION_FAIL(
"b = %wu\n"
"n = %wx\n"
"d = %wx\n"
"r1 = %wx\n"
"r2 = %wx\n"
, b, n, d, r1, r2);
}
}
TEST_FUNCTION_END(state);
}