blob: 0696c424801f1cff4ecfe8206e8c7aefe93138a9 [file] [log] [blame]
/*
* Copyright 2015 The WebRTC 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 in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include "rtc_base/bitbuffer.h"
#include <limits>
#include "rtc_base/arraysize.h"
#include "rtc_base/bytebuffer.h"
#include "test/gtest.h"
namespace rtc {
TEST(BitBufferTest, ConsumeBits) {
const uint8_t bytes[64] = {0};
BitBuffer buffer(bytes, 32);
uint64_t total_bits = 32 * 8;
EXPECT_EQ(total_bits, buffer.RemainingBitCount());
EXPECT_TRUE(buffer.ConsumeBits(3));
total_bits -= 3;
EXPECT_EQ(total_bits, buffer.RemainingBitCount());
EXPECT_TRUE(buffer.ConsumeBits(3));
total_bits -= 3;
EXPECT_EQ(total_bits, buffer.RemainingBitCount());
EXPECT_TRUE(buffer.ConsumeBits(15));
total_bits -= 15;
EXPECT_EQ(total_bits, buffer.RemainingBitCount());
EXPECT_TRUE(buffer.ConsumeBits(37));
total_bits -= 37;
EXPECT_EQ(total_bits, buffer.RemainingBitCount());
EXPECT_FALSE(buffer.ConsumeBits(32 * 8));
EXPECT_EQ(total_bits, buffer.RemainingBitCount());
}
TEST(BitBufferTest, ReadBytesAligned) {
const uint8_t bytes[] = {0x0A, 0xBC, 0xDE, 0xF1, 0x23, 0x45, 0x67, 0x89};
uint8_t val8;
uint16_t val16;
uint32_t val32;
BitBuffer buffer(bytes, 8);
EXPECT_TRUE(buffer.ReadUInt8(&val8));
EXPECT_EQ(0x0Au, val8);
EXPECT_TRUE(buffer.ReadUInt8(&val8));
EXPECT_EQ(0xBCu, val8);
EXPECT_TRUE(buffer.ReadUInt16(&val16));
EXPECT_EQ(0xDEF1u, val16);
EXPECT_TRUE(buffer.ReadUInt32(&val32));
EXPECT_EQ(0x23456789u, val32);
}
TEST(BitBufferTest, ReadBytesOffset4) {
const uint8_t bytes[] = {0x0A, 0xBC, 0xDE, 0xF1, 0x23,
0x45, 0x67, 0x89, 0x0A};
uint8_t val8;
uint16_t val16;
uint32_t val32;
BitBuffer buffer(bytes, 9);
EXPECT_TRUE(buffer.ConsumeBits(4));
EXPECT_TRUE(buffer.ReadUInt8(&val8));
EXPECT_EQ(0xABu, val8);
EXPECT_TRUE(buffer.ReadUInt8(&val8));
EXPECT_EQ(0xCDu, val8);
EXPECT_TRUE(buffer.ReadUInt16(&val16));
EXPECT_EQ(0xEF12u, val16);
EXPECT_TRUE(buffer.ReadUInt32(&val32));
EXPECT_EQ(0x34567890u, val32);
}
TEST(BitBufferTest, ReadBytesOffset3) {
// The pattern we'll check against is counting down from 0b1111. It looks
// weird here because it's all offset by 3.
// Byte pattern is:
// 56701234
// 0b00011111,
// 0b11011011,
// 0b10010111,
// 0b01010011,
// 0b00001110,
// 0b11001010,
// 0b10000110,
// 0b01000010
// xxxxx <-- last 5 bits unused.
// The bytes. It almost looks like counting down by two at a time, except the
// jump at 5->3->0, since that's when the high bit is turned off.
const uint8_t bytes[] = {0x1F, 0xDB, 0x97, 0x53, 0x0E, 0xCA, 0x86, 0x42};
uint8_t val8;
uint16_t val16;
uint32_t val32;
BitBuffer buffer(bytes, 8);
EXPECT_TRUE(buffer.ConsumeBits(3));
EXPECT_TRUE(buffer.ReadUInt8(&val8));
EXPECT_EQ(0xFEu, val8);
EXPECT_TRUE(buffer.ReadUInt16(&val16));
EXPECT_EQ(0xDCBAu, val16);
EXPECT_TRUE(buffer.ReadUInt32(&val32));
EXPECT_EQ(0x98765432u, val32);
// 5 bits left unread. Not enough to read a uint8_t.
EXPECT_EQ(5u, buffer.RemainingBitCount());
EXPECT_FALSE(buffer.ReadUInt8(&val8));
}
TEST(BitBufferTest, ReadBits) {
// Bit values are:
// 0b01001101,
// 0b00110010
const uint8_t bytes[] = {0x4D, 0x32};
uint32_t val;
BitBuffer buffer(bytes, 2);
EXPECT_TRUE(buffer.ReadBits(&val, 3));
// 0b010
EXPECT_EQ(0x2u, val);
EXPECT_TRUE(buffer.ReadBits(&val, 2));
// 0b01
EXPECT_EQ(0x1u, val);
EXPECT_TRUE(buffer.ReadBits(&val, 7));
// 0b1010011
EXPECT_EQ(0x53u, val);
EXPECT_TRUE(buffer.ReadBits(&val, 2));
// 0b00
EXPECT_EQ(0x0u, val);
EXPECT_TRUE(buffer.ReadBits(&val, 1));
// 0b1
EXPECT_EQ(0x1u, val);
EXPECT_TRUE(buffer.ReadBits(&val, 1));
// 0b0
EXPECT_EQ(0x0u, val);
EXPECT_FALSE(buffer.ReadBits(&val, 1));
}
TEST(BitBufferTest, SetOffsetValues) {
uint8_t bytes[4] = {0};
BitBufferWriter buffer(bytes, 4);
size_t byte_offset, bit_offset;
// Bit offsets are [0,7].
EXPECT_TRUE(buffer.Seek(0, 0));
EXPECT_TRUE(buffer.Seek(0, 7));
buffer.GetCurrentOffset(&byte_offset, &bit_offset);
EXPECT_EQ(0u, byte_offset);
EXPECT_EQ(7u, bit_offset);
EXPECT_FALSE(buffer.Seek(0, 8));
buffer.GetCurrentOffset(&byte_offset, &bit_offset);
EXPECT_EQ(0u, byte_offset);
EXPECT_EQ(7u, bit_offset);
// Byte offsets are [0,length]. At byte offset length, the bit offset must be
// 0.
EXPECT_TRUE(buffer.Seek(0, 0));
EXPECT_TRUE(buffer.Seek(2, 4));
buffer.GetCurrentOffset(&byte_offset, &bit_offset);
EXPECT_EQ(2u, byte_offset);
EXPECT_EQ(4u, bit_offset);
EXPECT_TRUE(buffer.Seek(4, 0));
EXPECT_FALSE(buffer.Seek(5, 0));
buffer.GetCurrentOffset(&byte_offset, &bit_offset);
EXPECT_EQ(4u, byte_offset);
EXPECT_EQ(0u, bit_offset);
EXPECT_FALSE(buffer.Seek(4, 1));
// Disable death test on Android because it relies on fork() and doesn't play
// nicely.
#if GTEST_HAS_DEATH_TEST
#if !defined(WEBRTC_ANDROID)
// Passing a null out parameter is death.
EXPECT_DEATH(buffer.GetCurrentOffset(&byte_offset, nullptr), "");
#endif
#endif
}
uint64_t GolombEncoded(uint32_t val) {
val++;
uint32_t bit_counter = val;
uint64_t bit_count = 0;
while (bit_counter > 0) {
bit_count++;
bit_counter >>= 1;
}
return static_cast<uint64_t>(val) << (64 - (bit_count * 2 - 1));
}
TEST(BitBufferTest, GolombUint32Values) {
ByteBufferWriter byteBuffer;
byteBuffer.Resize(16);
BitBuffer buffer(reinterpret_cast<const uint8_t*>(byteBuffer.Data()),
byteBuffer.Capacity());
// Test over the uint32_t range with a large enough step that the test doesn't
// take forever. Around 20,000 iterations should do.
const int kStep = std::numeric_limits<uint32_t>::max() / 20000;
for (uint32_t i = 0; i < std::numeric_limits<uint32_t>::max() - kStep;
i += kStep) {
uint64_t encoded_val = GolombEncoded(i);
byteBuffer.Clear();
byteBuffer.WriteUInt64(encoded_val);
uint32_t decoded_val;
EXPECT_TRUE(buffer.Seek(0, 0));
EXPECT_TRUE(buffer.ReadExponentialGolomb(&decoded_val));
EXPECT_EQ(i, decoded_val);
}
}
TEST(BitBufferTest, SignedGolombValues) {
uint8_t golomb_bits[] = {
0x80, // 1
0x40, // 010
0x60, // 011
0x20, // 00100
0x38, // 00111
};
int32_t expected[] = {0, 1, -1, 2, -3};
for (size_t i = 0; i < sizeof(golomb_bits); ++i) {
BitBuffer buffer(&golomb_bits[i], 1);
int32_t decoded_val;
ASSERT_TRUE(buffer.ReadSignedExponentialGolomb(&decoded_val));
EXPECT_EQ(expected[i], decoded_val)
<< "Mismatch in expected/decoded value for golomb_bits[" << i
<< "]: " << static_cast<int>(golomb_bits[i]);
}
}
TEST(BitBufferTest, NoGolombOverread) {
const uint8_t bytes[] = {0x00, 0xFF, 0xFF};
// Make sure the bit buffer correctly enforces byte length on golomb reads.
// If it didn't, the above buffer would be valid at 3 bytes.
BitBuffer buffer(bytes, 1);
uint32_t decoded_val;
EXPECT_FALSE(buffer.ReadExponentialGolomb(&decoded_val));
BitBuffer longer_buffer(bytes, 2);
EXPECT_FALSE(longer_buffer.ReadExponentialGolomb(&decoded_val));
BitBuffer longest_buffer(bytes, 3);
EXPECT_TRUE(longest_buffer.ReadExponentialGolomb(&decoded_val));
// Golomb should have read 9 bits, so 0x01FF, and since it is golomb, the
// result is 0x01FF - 1 = 0x01FE.
EXPECT_EQ(0x01FEu, decoded_val);
}
TEST(BitBufferWriterTest, SymmetricReadWrite) {
uint8_t bytes[16] = {0};
BitBufferWriter buffer(bytes, 4);
// Write some bit data at various sizes.
EXPECT_TRUE(buffer.WriteBits(0x2u, 3));
EXPECT_TRUE(buffer.WriteBits(0x1u, 2));
EXPECT_TRUE(buffer.WriteBits(0x53u, 7));
EXPECT_TRUE(buffer.WriteBits(0x0u, 2));
EXPECT_TRUE(buffer.WriteBits(0x1u, 1));
EXPECT_TRUE(buffer.WriteBits(0x1ABCDu, 17));
// That should be all that fits in the buffer.
EXPECT_FALSE(buffer.WriteBits(1, 1));
EXPECT_TRUE(buffer.Seek(0, 0));
uint32_t val;
EXPECT_TRUE(buffer.ReadBits(&val, 3));
EXPECT_EQ(0x2u, val);
EXPECT_TRUE(buffer.ReadBits(&val, 2));
EXPECT_EQ(0x1u, val);
EXPECT_TRUE(buffer.ReadBits(&val, 7));
EXPECT_EQ(0x53u, val);
EXPECT_TRUE(buffer.ReadBits(&val, 2));
EXPECT_EQ(0x0u, val);
EXPECT_TRUE(buffer.ReadBits(&val, 1));
EXPECT_EQ(0x1u, val);
EXPECT_TRUE(buffer.ReadBits(&val, 17));
EXPECT_EQ(0x1ABCDu, val);
// And there should be nothing left.
EXPECT_FALSE(buffer.ReadBits(&val, 1));
}
TEST(BitBufferWriterTest, SymmetricBytesMisaligned) {
uint8_t bytes[16] = {0};
BitBufferWriter buffer(bytes, 16);
// Offset 3, to get things misaligned.
EXPECT_TRUE(buffer.ConsumeBits(3));
EXPECT_TRUE(buffer.WriteUInt8(0x12u));
EXPECT_TRUE(buffer.WriteUInt16(0x3456u));
EXPECT_TRUE(buffer.WriteUInt32(0x789ABCDEu));
buffer.Seek(0, 3);
uint8_t val8;
uint16_t val16;
uint32_t val32;
EXPECT_TRUE(buffer.ReadUInt8(&val8));
EXPECT_EQ(0x12u, val8);
EXPECT_TRUE(buffer.ReadUInt16(&val16));
EXPECT_EQ(0x3456u, val16);
EXPECT_TRUE(buffer.ReadUInt32(&val32));
EXPECT_EQ(0x789ABCDEu, val32);
}
TEST(BitBufferWriterTest, SymmetricGolomb) {
char test_string[] = "my precious";
uint8_t bytes[64] = {0};
BitBufferWriter buffer(bytes, 64);
for (size_t i = 0; i < arraysize(test_string); ++i) {
EXPECT_TRUE(buffer.WriteExponentialGolomb(test_string[i]));
}
buffer.Seek(0, 0);
for (size_t i = 0; i < arraysize(test_string); ++i) {
uint32_t val;
EXPECT_TRUE(buffer.ReadExponentialGolomb(&val));
EXPECT_LE(val, std::numeric_limits<uint8_t>::max());
EXPECT_EQ(test_string[i], static_cast<char>(val));
}
}
TEST(BitBufferWriterTest, WriteClearsBits) {
uint8_t bytes[] = {0xFF, 0xFF};
BitBufferWriter buffer(bytes, 2);
EXPECT_TRUE(buffer.ConsumeBits(3));
EXPECT_TRUE(buffer.WriteBits(0, 1));
EXPECT_EQ(0xEFu, bytes[0]);
EXPECT_TRUE(buffer.WriteBits(0, 3));
EXPECT_EQ(0xE1u, bytes[0]);
EXPECT_TRUE(buffer.WriteBits(0, 2));
EXPECT_EQ(0xE0u, bytes[0]);
EXPECT_EQ(0x7F, bytes[1]);
}
} // namespace rtc