BLI_math_bits_test.cc

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/* SPDX-FileCopyrightText: 2023 Blender Authors
 *
 * SPDX-License-Identifier: Apache-2.0 */
 
#include "BLI_math_bits.h"
#include "testing/testing.h"
#include <iostream>
 
TEST(math_bits, BitscanReverseClearUint)
{
  uint a = 1234;
  EXPECT_EQ(bitscan_reverse_clear_uint(&a), 21);
  EXPECT_EQ(a, 210);
  EXPECT_EQ(bitscan_reverse_clear_uint(&a), 24);
  EXPECT_EQ(a, 82);
  EXPECT_EQ(bitscan_reverse_clear_uint(&a), 25);
  EXPECT_EQ(a, 18);
  EXPECT_EQ(bitscan_reverse_clear_uint(&a), 27);
  EXPECT_EQ(a, 2);
  EXPECT_EQ(bitscan_reverse_clear_uint(&a), 30);
  EXPECT_EQ(a, 0);
 
  a = 3563987529;
  EXPECT_EQ(bitscan_reverse_clear_uint(&a), 0);
  EXPECT_EQ(a, 1416503881);
  EXPECT_EQ(bitscan_reverse_clear_uint(&a), 1);
  EXPECT_EQ(a, 342762057);
  EXPECT_EQ(bitscan_reverse_clear_uint(&a), 3);
  EXPECT_EQ(a, 74326601);
  EXPECT_EQ(bitscan_reverse_clear_uint(&a), 5);
  EXPECT_EQ(a, 7217737);
  EXPECT_EQ(bitscan_reverse_clear_uint(&a), 9);
  EXPECT_EQ(a, 3023433);
  EXPECT_EQ(bitscan_reverse_clear_uint(&a), 10);
  EXPECT_EQ(a, 926281);
  EXPECT_EQ(bitscan_reverse_clear_uint(&a), 12);
  EXPECT_EQ(a, 401993);
  EXPECT_EQ(bitscan_reverse_clear_uint(&a), 13);
  EXPECT_EQ(a, 139849);
  EXPECT_EQ(bitscan_reverse_clear_uint(&a), 14);
  EXPECT_EQ(a, 8777);
  EXPECT_EQ(bitscan_reverse_clear_uint(&a), 18);
  EXPECT_EQ(a, 585);
  EXPECT_EQ(bitscan_reverse_clear_uint(&a), 22);
  EXPECT_EQ(a, 73);
  EXPECT_EQ(bitscan_reverse_clear_uint(&a), 25);
  EXPECT_EQ(a, 9);
  EXPECT_EQ(bitscan_reverse_clear_uint(&a), 28);
  EXPECT_EQ(a, 1);
  EXPECT_EQ(bitscan_reverse_clear_uint(&a), 31);
  EXPECT_EQ(a, 0);
}
 
TEST(math_bits, PopCount)
{
  {
    EXPECT_EQ(count_bits_i(0), 0);
    EXPECT_EQ(count_bits_uint64(0), 0);
  }
  {
    const int value = (1 << 0) | (1 << 5) | (1 << 7);
    const int count_32 = count_bits_i(value);
    const int count_64 = count_bits_uint64(value);
    EXPECT_EQ(count_32, 3);
    EXPECT_EQ(count_64, 3);
  }
  {
    const uint64_t value = (uint64_t(1) << 0) | (uint64_t(1) << 50);
    const int count = count_bits_uint64(value);
    EXPECT_EQ(count, 2);
  }
  {
    const int value = -1;
    const int count = count_bits_i(value);
    EXPECT_EQ(count, 32);
  }
  {
    const uint64_t value = -1;
    const int count = count_bits_uint64(value);
    EXPECT_EQ(count, 64);
  }
}