101 lines
3.4 KiB
C++
101 lines
3.4 KiB
C++
/*
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* Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*
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*/
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#include "precompiled.hpp"
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#include "utilities/count_leading_zeros.hpp"
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#include "utilities/globalDefinitions.hpp"
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#include "unittest.hpp"
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#include <limits>
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#include <type_traits>
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template <typename T> void one_or_two_set_bits() {
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uint32_t bit1_pos = 0;
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uint32_t bits = sizeof(T) * BitsPerByte;
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uint32_t limit = bits - (std::is_signed<T>::value ? 1 : 0);
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for (uint64_t ix = 1; bit1_pos < limit; ix = ix * 2, ++bit1_pos) {
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uint32_t bit2_pos = 0;
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for (uint64_t jx = 1; bit2_pos < limit; jx = jx * 2, ++bit2_pos) {
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T value = T(ix | jx);
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EXPECT_EQ((uint32_t)(bits - 1u - MAX2(bit1_pos, bit2_pos)), count_leading_zeros(value))
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<< "value = " << value;
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}
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}
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}
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TEST(count_leading_zeros, one_or_two_set_bits) {
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one_or_two_set_bits<int8_t>();
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one_or_two_set_bits<int16_t>();
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one_or_two_set_bits<int32_t>();
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one_or_two_set_bits<int64_t>();
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one_or_two_set_bits<uint8_t>();
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one_or_two_set_bits<uint16_t>();
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one_or_two_set_bits<uint32_t>();
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one_or_two_set_bits<uint64_t>();
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}
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template <typename T> void high_zeros_low_ones() {
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uint32_t number_of_leading_zeros = (std::is_signed<T>::value ? 1 : 0);
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T value = std::numeric_limits<T>::max();
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for ( ; value != 0; value >>= 1, ++number_of_leading_zeros) {
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EXPECT_EQ(number_of_leading_zeros, count_leading_zeros(value))
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<< "value = " << value;
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}
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}
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TEST(count_leading_zeros, high_zeros_low_ones) {
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high_zeros_low_ones<int8_t>();
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high_zeros_low_ones<int16_t>();
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high_zeros_low_ones<int32_t>();
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high_zeros_low_ones<int64_t>();
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high_zeros_low_ones<uint8_t>();
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high_zeros_low_ones<uint16_t>();
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high_zeros_low_ones<uint32_t>();
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high_zeros_low_ones<uint64_t>();
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}
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template <typename T> void high_ones_low_zeros() {
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T value = std::numeric_limits<T>::max();
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uint32_t number_of_leading_zeros = (std::is_signed<T>::value ? 1 : 0);
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for (uint64_t i = 1; value != 0; value -= i, i <<= 1) {
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EXPECT_EQ(number_of_leading_zeros, count_leading_zeros(value))
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<< "value = " << value;
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}
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value = (T)(~((uint64_t)0)); // all ones
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EXPECT_EQ(0u, count_leading_zeros(value))
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<< "value = " << value;
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}
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TEST(count_leading_zeros, high_ones_low_zeros) {
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high_ones_low_zeros<int8_t>();
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high_ones_low_zeros<int16_t>();
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high_ones_low_zeros<int32_t>();
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high_ones_low_zeros<int64_t>();
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high_ones_low_zeros<uint8_t>();
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high_ones_low_zeros<uint16_t>();
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high_ones_low_zeros<uint32_t>();
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high_ones_low_zeros<uint64_t>();
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}
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