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- // 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 "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 < std::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 < std::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
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