namespace media {
+static void SetBit(uint8* 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 value8;
uint64 value64;
EXPECT_FALSE(reader1.SkipBits(1));
}
+TEST(BitReaderTest, VariableSkipBitsTest) {
+ uint8 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 < arraysize(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 < arraysize(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;