/*
 * 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
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 * questions.
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 */

#include "precompiled.hpp"
#include "utilities/count_leading_zeros.hpp"
#include "utilities/globalDefinitions.hpp"
#include "unittest.hpp"

TEST(count_leading_zeros, one_or_two_set_bits) {
  unsigned i = 0;                  // Position of a set bit.
  for (uint32_t ix = 1; ix != 0; ix <<= 1, ++i) {
    unsigned j = 0;                // Position of a set bit.
    for (uint32_t jx = 1; jx != 0; jx <<= 1, ++j) {
      uint32_t value = ix | jx;
      EXPECT_EQ(31u - MAX2(i, j), count_leading_zeros(value))
        << "value = " << value;
    }
  }
}

TEST(count_leading_zeros, high_zeros_low_ones) {
  unsigned i = 0;                  // Number of leading zeros
  uint32_t value = ~(uint32_t)0;
  for ( ; value != 0; value >>= 1, ++i) {
    EXPECT_EQ(i, count_leading_zeros(value))
      << "value = " << value;
  }
}

TEST(count_leading_zeros, high_ones_low_zeros) {
  uint32_t value = ~(uint32_t)0;
  for ( ; value != 0; value <<= 1) {
    EXPECT_EQ(0u, count_leading_zeros(value))
      << "value = " << value;
  }
}