H264 bitstream parser.

webrtc/base/bitbuffer_unittest.cc

 /*
  *  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.
  */
 
@@ skipping 187 matching lines @@
     uint64 encoded_val = GolombEncoded(i);
     byteBuffer.Clear();
     byteBuffer.WriteUInt64(encoded_val);
     uint32 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 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 decoded_val;
   EXPECT_FALSE(buffer.ReadExponentialGolomb(&decoded_val));
 
   BitBuffer longer_buffer(bytes, 2);
   EXPECT_FALSE(longer_buffer.ReadExponentialGolomb(&decoded_val));
@@ skipping 82 matching lines @@
   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