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// Copyright (c) the JPEG XL Project Authors. All rights reserved.
//
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
#include "lib/jxl/base/bits.h"
#include <cstddef>
#include <cstdint>
#include "lib/jxl/testing.h"
namespace jxl {
namespace {
TEST(BitsTest, TestNumZeroBits) {
// Zero input is well-defined.
EXPECT_EQ(32u, Num0BitsAboveMS1Bit(0u));
EXPECT_EQ(64u, Num0BitsAboveMS1Bit(0ull));
EXPECT_EQ(32u, Num0BitsBelowLS1Bit(0u));
EXPECT_EQ(64u, Num0BitsBelowLS1Bit(0ull));
EXPECT_EQ(31u, Num0BitsAboveMS1Bit(1u));
EXPECT_EQ(30u, Num0BitsAboveMS1Bit(2u));
EXPECT_EQ(63u, Num0BitsAboveMS1Bit(1ull));
EXPECT_EQ(62u, Num0BitsAboveMS1Bit(2ull));
EXPECT_EQ(0u, Num0BitsBelowLS1Bit(1u));
EXPECT_EQ(0u, Num0BitsBelowLS1Bit(1ull));
EXPECT_EQ(1u, Num0BitsBelowLS1Bit(2u));
EXPECT_EQ(1u, Num0BitsBelowLS1Bit(2ull));
EXPECT_EQ(0u, Num0BitsAboveMS1Bit(0x80000000u));
EXPECT_EQ(0u, Num0BitsAboveMS1Bit(0x8000000000000000ull));
EXPECT_EQ(31u, Num0BitsBelowLS1Bit(0x80000000u));
EXPECT_EQ(63u, Num0BitsBelowLS1Bit(0x8000000000000000ull));
}
TEST(BitsTest, TestFloorLog2) {
// for input = [1, 7]
const size_t expected[7] = {0, 1, 1, 2, 2, 2, 2};
for (uint32_t i = 1; i <= 7; ++i) {
EXPECT_EQ(expected[i - 1], FloorLog2Nonzero(i)) << " " << i;
EXPECT_EQ(expected[i - 1], FloorLog2Nonzero(static_cast<uint64_t>(i)))
<< " " << i;
}
EXPECT_EQ(11u, FloorLog2Nonzero(0x00000fffu)); // 4095
EXPECT_EQ(12u, FloorLog2Nonzero(0x00001000u)); // 4096
EXPECT_EQ(12u, FloorLog2Nonzero(0x00001001u)); // 4097
EXPECT_EQ(31u, FloorLog2Nonzero(0x80000000u));
EXPECT_EQ(31u, FloorLog2Nonzero(0x80000001u));
EXPECT_EQ(31u, FloorLog2Nonzero(0xFFFFFFFFu));
EXPECT_EQ(31u, FloorLog2Nonzero(0x80000000ull));
EXPECT_EQ(31u, FloorLog2Nonzero(0x80000001ull));
EXPECT_EQ(31u, FloorLog2Nonzero(0xFFFFFFFFull));
EXPECT_EQ(63u, FloorLog2Nonzero(0x8000000000000000ull));
EXPECT_EQ(63u, FloorLog2Nonzero(0x8000000000000001ull));
EXPECT_EQ(63u, FloorLog2Nonzero(0xFFFFFFFFFFFFFFFFull));
}
TEST(BitsTest, TestCeilLog2) {
// for input = [1, 7]
const size_t expected[7] = {0, 1, 2, 2, 3, 3, 3};
for (uint32_t i = 1; i <= 7; ++i) {
EXPECT_EQ(expected[i - 1], CeilLog2Nonzero(i)) << " " << i;
EXPECT_EQ(expected[i - 1], CeilLog2Nonzero(static_cast<uint64_t>(i)))
<< " " << i;
}
EXPECT_EQ(12u, CeilLog2Nonzero(0x00000fffu)); // 4095
EXPECT_EQ(12u, CeilLog2Nonzero(0x00001000u)); // 4096
EXPECT_EQ(13u, CeilLog2Nonzero(0x00001001u)); // 4097
EXPECT_EQ(31u, CeilLog2Nonzero(0x80000000u));
EXPECT_EQ(32u, CeilLog2Nonzero(0x80000001u));
EXPECT_EQ(32u, CeilLog2Nonzero(0xFFFFFFFFu));
EXPECT_EQ(31u, CeilLog2Nonzero(0x80000000ull));
EXPECT_EQ(32u, CeilLog2Nonzero(0x80000001ull));
EXPECT_EQ(32u, CeilLog2Nonzero(0xFFFFFFFFull));
EXPECT_EQ(63u, CeilLog2Nonzero(0x8000000000000000ull));
EXPECT_EQ(64u, CeilLog2Nonzero(0x8000000000000001ull));
EXPECT_EQ(64u, CeilLog2Nonzero(0xFFFFFFFFFFFFFFFFull));
}
} // namespace
} // namespace jxl
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