blob: ee04e3603d50a673498fab8be87f7a65733d2774 [file] [log] [blame]
// Copyright (c) 2012 The Chromium 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 "media/base/bit_reader.h"
#include <stddef.h>
#include <stdint.h>
#include "base/cxx17_backports.h"
#include "testing/gtest/include/gtest/gtest.h"
namespace media {
static void SetBit(uint8_t* buf, size_t size, size_t bit_pos) {
size_t byte_pos = bit_pos / 8;
bit_pos -= byte_pos * 8;
DCHECK_LT(byte_pos, size);
buf[byte_pos] |= (1 << (7 - bit_pos));
}
TEST(BitReaderTest, NormalOperationTest) {
uint8_t value8;
uint64_t value64;
// 0101 0101 1001 1001 repeats 4 times
uint8_t buffer[] = {0x55, 0x99, 0x55, 0x99, 0x55, 0x99, 0x55, 0x99};
BitReader reader1(buffer, 6); // Initialize with 6 bytes only
EXPECT_TRUE(reader1.ReadBits(1, &value8));
EXPECT_EQ(value8, 0);
EXPECT_TRUE(reader1.ReadBits(8, &value8));
EXPECT_EQ(value8, 0xab); // 1010 1011
EXPECT_TRUE(reader1.ReadBits(7, &value64));
EXPECT_TRUE(reader1.ReadBits(32, &value64));
EXPECT_EQ(value64, 0x55995599u);
EXPECT_FALSE(reader1.ReadBits(1, &value8));
value8 = 0xff;
EXPECT_TRUE(reader1.ReadBits(0, &value8));
EXPECT_EQ(value8, 0);
BitReader reader2(buffer, 8);
EXPECT_TRUE(reader2.ReadBits(64, &value64));
EXPECT_EQ(value64, 0x5599559955995599ull);
EXPECT_FALSE(reader2.ReadBits(1, &value8));
EXPECT_TRUE(reader2.ReadBits(0, &value8));
}
TEST(BitReaderTest, ReadBeyondEndTest) {
uint8_t value8;
uint8_t buffer[] = {0x12};
BitReader reader1(buffer, sizeof(buffer));
EXPECT_TRUE(reader1.ReadBits(4, &value8));
EXPECT_FALSE(reader1.ReadBits(5, &value8));
EXPECT_FALSE(reader1.ReadBits(1, &value8));
EXPECT_TRUE(reader1.ReadBits(0, &value8));
}
TEST(BitReaderTest, SkipBitsTest) {
uint8_t value8;
uint8_t buffer[] = {0x0a, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15};
BitReader reader1(buffer, sizeof(buffer));
EXPECT_TRUE(reader1.SkipBits(2));
EXPECT_TRUE(reader1.ReadBits(3, &value8));
EXPECT_EQ(value8, 1);
EXPECT_TRUE(reader1.SkipBits(11));
EXPECT_TRUE(reader1.ReadBits(8, &value8));
EXPECT_EQ(value8, 3);
EXPECT_TRUE(reader1.SkipBits(76));
EXPECT_TRUE(reader1.ReadBits(4, &value8));
EXPECT_EQ(value8, 13);
EXPECT_FALSE(reader1.SkipBits(100));
EXPECT_TRUE(reader1.SkipBits(0));
EXPECT_FALSE(reader1.SkipBits(1));
}
TEST(BitReaderTest, VariableSkipBitsTest) {
uint8_t buffer[256] = {0};
// The test alternates between ReadBits and SkipBits.
// The first number is the number of bits to read, the second one is the
// number of bits to skip. The number of bits to read was arbitrarily chosen
// while the number of bits to skip was chosen so as to cover from small skips
// to large skips.
const size_t pattern_read_skip[][2] = {
{ 5, 17 },
{ 4, 34 },
{ 0, 44 },
{ 3, 4 }, // Note: aligned read.
{ 7, 7 }, // Note: both read&skip cross byte boundary.
{ 17, 68 },
{ 7, 102 },
{ 9, 204 },
{ 3, 408 } };
// Set bits to one only for the first and last bit of each read
// in the pattern.
size_t pos = 0;
for (size_t k = 0; k < base::size(pattern_read_skip); ++k) {
const size_t read_bit_count = pattern_read_skip[k][0];
if (read_bit_count > 0) {
SetBit(buffer, sizeof(buffer), pos);
SetBit(buffer, sizeof(buffer), pos + read_bit_count - 1);
pos += read_bit_count;
}
pos += pattern_read_skip[k][1];
}
// Run the test.
BitReader bit_reader(buffer, sizeof(buffer));
EXPECT_EQ(bit_reader.bits_available(), static_cast<int>(sizeof(buffer) * 8));
for (size_t k = 0; k < base::size(pattern_read_skip); ++k) {
const size_t read_bit_count = pattern_read_skip[k][0];
if (read_bit_count > 0) {
int value;
EXPECT_TRUE(bit_reader.ReadBits(read_bit_count, &value));
EXPECT_EQ(value, 1 | (1 << (read_bit_count - 1)));
}
EXPECT_TRUE(bit_reader.SkipBits(pattern_read_skip[k][1]));
}
}
TEST(BitReaderTest, BitsReadTest) {
int value;
bool flag;
uint8_t buffer[] = {0x0a, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15};
BitReader reader1(buffer, sizeof(buffer));
EXPECT_EQ(reader1.bits_available(), 120);
EXPECT_TRUE(reader1.SkipBits(2));
EXPECT_EQ(reader1.bits_read(), 2);
EXPECT_EQ(reader1.bits_available(), 118);
EXPECT_TRUE(reader1.ReadBits(3, &value));
EXPECT_EQ(reader1.bits_read(), 5);
EXPECT_EQ(reader1.bits_available(), 115);
EXPECT_TRUE(reader1.ReadFlag(&flag));
EXPECT_EQ(reader1.bits_read(), 6);
EXPECT_EQ(reader1.bits_available(), 114);
EXPECT_TRUE(reader1.SkipBits(76));
EXPECT_EQ(reader1.bits_read(), 82);
EXPECT_EQ(reader1.bits_available(), 38);
}
} // namespace media