1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #include "media/base/bit_reader.h" 6 7 #include "testing/gtest/include/gtest/gtest.h" 8 9 namespace media { 10 11 static void SetBit(uint8* buf, size_t size, size_t bit_pos) { 12 size_t byte_pos = bit_pos / 8; 13 bit_pos -= byte_pos * 8; 14 DCHECK_LT(byte_pos, size); 15 buf[byte_pos] |= (1 << (7 - bit_pos)); 16 } 17 18 TEST(BitReaderTest, NormalOperationTest) { 19 uint8 value8; 20 uint64 value64; 21 // 0101 0101 1001 1001 repeats 4 times 22 uint8 buffer[] = {0x55, 0x99, 0x55, 0x99, 0x55, 0x99, 0x55, 0x99}; 23 BitReader reader1(buffer, 6); // Initialize with 6 bytes only 24 25 EXPECT_TRUE(reader1.ReadBits(1, &value8)); 26 EXPECT_EQ(value8, 0); 27 EXPECT_TRUE(reader1.ReadBits(8, &value8)); 28 EXPECT_EQ(value8, 0xab); // 1010 1011 29 EXPECT_TRUE(reader1.ReadBits(7, &value64)); 30 EXPECT_TRUE(reader1.ReadBits(32, &value64)); 31 EXPECT_EQ(value64, 0x55995599u); 32 EXPECT_FALSE(reader1.ReadBits(1, &value8)); 33 value8 = 0xff; 34 EXPECT_TRUE(reader1.ReadBits(0, &value8)); 35 EXPECT_EQ(value8, 0); 36 37 BitReader reader2(buffer, 8); 38 EXPECT_TRUE(reader2.ReadBits(64, &value64)); 39 EXPECT_EQ(value64, 0x5599559955995599ull); 40 EXPECT_FALSE(reader2.ReadBits(1, &value8)); 41 EXPECT_TRUE(reader2.ReadBits(0, &value8)); 42 } 43 44 TEST(BitReaderTest, ReadBeyondEndTest) { 45 uint8 value8; 46 uint8 buffer[] = {0x12}; 47 BitReader reader1(buffer, sizeof(buffer)); 48 49 EXPECT_TRUE(reader1.ReadBits(4, &value8)); 50 EXPECT_FALSE(reader1.ReadBits(5, &value8)); 51 EXPECT_FALSE(reader1.ReadBits(1, &value8)); 52 EXPECT_TRUE(reader1.ReadBits(0, &value8)); 53 } 54 55 TEST(BitReaderTest, SkipBitsTest) { 56 uint8 value8; 57 uint8 buffer[] = { 0x0a, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 }; 58 BitReader reader1(buffer, sizeof(buffer)); 59 60 EXPECT_TRUE(reader1.SkipBits(2)); 61 EXPECT_TRUE(reader1.ReadBits(3, &value8)); 62 EXPECT_EQ(value8, 1); 63 EXPECT_TRUE(reader1.SkipBits(11)); 64 EXPECT_TRUE(reader1.ReadBits(8, &value8)); 65 EXPECT_EQ(value8, 3); 66 EXPECT_TRUE(reader1.SkipBits(76)); 67 EXPECT_TRUE(reader1.ReadBits(4, &value8)); 68 EXPECT_EQ(value8, 13); 69 EXPECT_FALSE(reader1.SkipBits(100)); 70 EXPECT_TRUE(reader1.SkipBits(0)); 71 EXPECT_FALSE(reader1.SkipBits(1)); 72 } 73 74 TEST(BitReaderTest, VariableSkipBitsTest) { 75 uint8 buffer[256] = {0}; 76 77 // The test alternates between ReadBits and SkipBits. 78 // The first number is the number of bits to read, the second one is the 79 // number of bits to skip. The number of bits to read was arbitrarily chosen 80 // while the number of bits to skip was chosen so as to cover from small skips 81 // to large skips. 82 const size_t pattern_read_skip[][2] = { 83 { 5, 17 }, 84 { 4, 34 }, 85 { 0, 44 }, 86 { 3, 4 }, // Note: aligned read. 87 { 7, 7 }, // Note: both read&skip cross byte boundary. 88 { 17, 68 }, 89 { 7, 102 }, 90 { 9, 204 }, 91 { 3, 408 } }; 92 93 // Set bits to one only for the first and last bit of each read 94 // in the pattern. 95 size_t pos = 0; 96 for (size_t k = 0; k < arraysize(pattern_read_skip); ++k) { 97 const size_t read_bit_count = pattern_read_skip[k][0]; 98 if (read_bit_count > 0) { 99 SetBit(buffer, sizeof(buffer), pos); 100 SetBit(buffer, sizeof(buffer), pos + read_bit_count - 1); 101 pos += read_bit_count; 102 } 103 pos += pattern_read_skip[k][1]; 104 } 105 106 // Run the test. 107 BitReader bit_reader(buffer, sizeof(buffer)); 108 EXPECT_EQ(bit_reader.bits_available(), static_cast<int>(sizeof(buffer) * 8)); 109 for (size_t k = 0; k < arraysize(pattern_read_skip); ++k) { 110 const size_t read_bit_count = pattern_read_skip[k][0]; 111 if (read_bit_count > 0) { 112 int value; 113 EXPECT_TRUE(bit_reader.ReadBits(read_bit_count, &value)); 114 EXPECT_EQ(value, 1 | (1 << (read_bit_count - 1))); 115 } 116 EXPECT_TRUE(bit_reader.SkipBits(pattern_read_skip[k][1])); 117 } 118 } 119 120 TEST(BitReaderTest, BitsReadTest) { 121 int value; 122 bool flag; 123 uint8 buffer[] = { 0x0a, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 }; 124 BitReader reader1(buffer, sizeof(buffer)); 125 EXPECT_EQ(reader1.bits_available(), 120); 126 127 EXPECT_TRUE(reader1.SkipBits(2)); 128 EXPECT_EQ(reader1.bits_read(), 2); 129 EXPECT_EQ(reader1.bits_available(), 118); 130 EXPECT_TRUE(reader1.ReadBits(3, &value)); 131 EXPECT_EQ(reader1.bits_read(), 5); 132 EXPECT_EQ(reader1.bits_available(), 115); 133 EXPECT_TRUE(reader1.ReadFlag(&flag)); 134 EXPECT_EQ(reader1.bits_read(), 6); 135 EXPECT_EQ(reader1.bits_available(), 114); 136 EXPECT_TRUE(reader1.SkipBits(76)); 137 EXPECT_EQ(reader1.bits_read(), 82); 138 EXPECT_EQ(reader1.bits_available(), 38); 139 } 140 141 } // namespace media 142
