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