Remove unused bit stream methods. (#1807)

This CL deletes methods from bit stream which are never used and moves
several to the anonymous namespace in the bit_stream test file.

3 files changed, 75 insertions, 725 deletions

diff --git a/source/util/bit_stream.cpp b/source/util/bit_stream.cpp
index a275a63a..f40a2290 100644
--- a/source/util/bit_stream.cpp
+++ b/source/util/bit_stream.cpp
@@ -197,41 +197,6 @@ bool ReadVariableWidthSigned(BitReaderInterface* reader, T* val,
 
 }  // namespace
 
-size_t Log2U64(uint64_t val) {
-  size_t res = 0;
-
-  if (val & 0xFFFFFFFF00000000) {
-    val >>= 32;
-    res |= 32;
-  }
-
-  if (val & 0xFFFF0000) {
-    val >>= 16;
-    res |= 16;
-  }
-
-  if (val & 0xFF00) {
-    val >>= 8;
-    res |= 8;
-  }
-
-  if (val & 0xF0) {
-    val >>= 4;
-    res |= 4;
-  }
-
-  if (val & 0xC) {
-    val >>= 2;
-    res |= 2;
-  }
-
-  if (val & 0x2) {
-    res |= 1;
-  }
-
-  return res;
-}
-
 void BitWriterInterface::WriteVariableWidthU64(uint64_t val,
                                                size_t chunk_length) {
   WriteVariableWidthUnsigned(this, val, chunk_length);
@@ -247,41 +212,11 @@ void BitWriterInterface::WriteVariableWidthU16(uint16_t val,
   WriteVariableWidthUnsigned(this, val, chunk_length);
 }
 
-void BitWriterInterface::WriteVariableWidthU8(uint8_t val,
-                                              size_t chunk_length) {
-  WriteVariableWidthUnsigned(this, val, chunk_length);
-}
-
 void BitWriterInterface::WriteVariableWidthS64(int64_t val, size_t chunk_length,
                                                size_t zigzag_exponent) {
   WriteVariableWidthSigned(this, val, chunk_length, zigzag_exponent);
 }
 
-void BitWriterInterface::WriteVariableWidthS32(int32_t val, size_t chunk_length,
-                                               size_t zigzag_exponent) {
-  WriteVariableWidthSigned(this, val, chunk_length, zigzag_exponent);
-}
-
-void BitWriterInterface::WriteVariableWidthS16(int16_t val, size_t chunk_length,
-                                               size_t zigzag_exponent) {
-  WriteVariableWidthSigned(this, val, chunk_length, zigzag_exponent);
-}
-
-void BitWriterInterface::WriteVariableWidthS8(int8_t val, size_t chunk_length,
-                                              size_t zigzag_exponent) {
-  WriteVariableWidthSigned(this, val, chunk_length, zigzag_exponent);
-}
-
-void BitWriterInterface::WriteFixedWidth(uint64_t val, uint64_t max_val) {
-  if (val > max_val) {
-    assert(0 && "WriteFixedWidth: value too wide");
-    return;
-  }
-
-  const size_t num_bits = 1 + Log2U64(max_val);
-  WriteBits(val, num_bits);
-}
-
 BitWriterWord64::BitWriterWord64(size_t reserve_bits) : end_(0) {
   buffer_.reserve(NumBitsToNumWords<64>(reserve_bits));
 }
@@ -340,36 +275,11 @@ bool BitReaderInterface::ReadVariableWidthU16(uint16_t* val,
   return ReadVariableWidthUnsigned(this, val, chunk_length);
 }
 
-bool BitReaderInterface::ReadVariableWidthU8(uint8_t* val,
-                                             size_t chunk_length) {
-  return ReadVariableWidthUnsigned(this, val, chunk_length);
-}
-
 bool BitReaderInterface::ReadVariableWidthS64(int64_t* val, size_t chunk_length,
                                               size_t zigzag_exponent) {
   return ReadVariableWidthSigned(this, val, chunk_length, zigzag_exponent);
 }
 
-bool BitReaderInterface::ReadVariableWidthS32(int32_t* val, size_t chunk_length,
-                                              size_t zigzag_exponent) {
-  return ReadVariableWidthSigned(this, val, chunk_length, zigzag_exponent);
-}
-
-bool BitReaderInterface::ReadVariableWidthS16(int16_t* val, size_t chunk_length,
-                                              size_t zigzag_exponent) {
-  return ReadVariableWidthSigned(this, val, chunk_length, zigzag_exponent);
-}
-
-bool BitReaderInterface::ReadVariableWidthS8(int8_t* val, size_t chunk_length,
-                                             size_t zigzag_exponent) {
-  return ReadVariableWidthSigned(this, val, chunk_length, zigzag_exponent);
-}
-
-bool BitReaderInterface::ReadFixedWidth(uint64_t* val, uint64_t max_val) {
-  const size_t num_bits = 1 + Log2U64(max_val);
-  return ReadBits(val, num_bits) == num_bits;
-}
-
 BitReaderWord64::BitReaderWord64(std::vector<uint64_t>&& buffer)
     : buffer_(std::move(buffer)), pos_(0) {}
 
diff --git a/source/util/bit_stream.h b/source/util/bit_stream.h
index 58165374..dd29e479 100644
--- a/source/util/bit_stream.h
+++ b/source/util/bit_stream.h
@@ -29,9 +29,6 @@
 namespace spvtools {
 namespace utils {
 
-// Returns rounded down log2(val). log2(0) is considered 0.
-size_t Log2U64(uint64_t val);
-
 // Terminology:
 // Bits - usually used for a uint64 word, first bit is the lowest.
 // Stream - std::string of '0' and '1', read left-to-right,
@@ -54,33 +51,6 @@ inline T GetLowerBits(T in, size_t num_bits) {
   return sizeof(T) * 8 == num_bits ? in : in & T((T(1) << num_bits) - T(1));
 }
 
-// Encodes signed integer as unsigned in zigzag order:
-//  0 -> 0
-// -1 -> 1
-//  1 -> 2
-// -2 -> 3
-//  2 -> 4
-// Motivation: -1 is 0xFF...FF what doesn't work very well with
-// WriteVariableWidth which prefers to have as many 0 bits as possible.
-inline uint64_t EncodeZigZag(int64_t val) { return (val << 1) ^ (val >> 63); }
-
-// Decodes signed integer encoded with EncodeZigZag.
-inline int64_t DecodeZigZag(uint64_t val) {
-  if (val & 1) {
-    // Negative.
-    // 1 -> -1
-    // 3 -> -2
-    // 5 -> -3
-    return -1 - (val >> 1);
-  } else {
-    // Non-negative.
-    // 0 -> 0
-    // 2 -> 1
-    // 4 -> 2
-    return val >> 1;
-  }
-}
-
 // Encodes signed integer as unsigned. This is a generalized version of
 // EncodeZigZag, designed to favor small positive numbers.
 // Values are transformed in blocks of 2^|block_exponent|.
@@ -113,111 +83,24 @@ inline int64_t DecodeZigZag(uint64_t val, size_t block_exponent) {
   }
 }
 
-// Converts |buffer| to a stream of '0' and '1'.
-template <typename T>
-std::string BufferToStream(const std::vector<T>& buffer) {
-  std::stringstream ss;
-  for (auto it = buffer.begin(); it != buffer.end(); ++it) {
-    std::string str = std::bitset<sizeof(T) * 8>(*it).to_string();
-    // Strings generated by std::bitset::to_string are read right to left.
-    // Reversing to left to right.
-    std::reverse(str.begin(), str.end());
-    ss << str;
-  }
-  return ss.str();
-}
-
-// Converts a left-to-right input string of '0' and '1' to a buffer of |T|
-// words.
-template <typename T>
-std::vector<T> StreamToBuffer(std::string str) {
-  // The input string is left-to-right, the input argument of std::bitset needs
-  // to right-to-left. Instead of reversing tokens, reverse the entire string
-  // and iterate tokens from end to begin.
-  std::reverse(str.begin(), str.end());
-  const int word_size = static_cast<int>(sizeof(T) * 8);
-  const int str_length = static_cast<int>(str.length());
-  std::vector<T> buffer;
-  buffer.reserve(NumBitsToNumWords<sizeof(T)>(str.length()));
-  for (int index = str_length - word_size; index >= 0; index -= word_size) {
-    buffer.push_back(static_cast<T>(
-        std::bitset<sizeof(T) * 8>(str, index, word_size).to_ullong()));
-  }
-  const size_t suffix_length = str.length() % word_size;
-  if (suffix_length != 0) {
-    buffer.push_back(static_cast<T>(
-        std::bitset<sizeof(T) * 8>(str, 0, suffix_length).to_ullong()));
-  }
-  return buffer;
-}
-
-// Adds '0' chars at the end of the string until the size is a multiple of N.
-template <size_t N>
-inline std::string PadToWord(std::string&& str) {
-  const size_t tail_length = str.size() % N;
-  if (tail_length != 0) str += std::string(N - tail_length, '0');
-  return std::move(str);
-}
-
-// Adds '0' chars at the end of the string until the size is a multiple of N.
-template <size_t N>
-inline std::string PadToWord(const std::string& str) {
-  return PadToWord<N>(std::string(str));
-}
-
-// Converts a left-to-right stream of bits to std::bitset.
-template <size_t N>
-inline std::bitset<N> StreamToBitset(std::string str) {
-  std::reverse(str.begin(), str.end());
-  return std::bitset<N>(str);
-}
-
-// Converts first |num_bits| of std::bitset to a left-to-right stream of bits.
-template <size_t N>
-inline std::string BitsetToStream(const std::bitset<N>& bits,
-                                  size_t num_bits = N) {
-  std::string str = bits.to_string().substr(N - num_bits);
-  std::reverse(str.begin(), str.end());
-  return str;
-}
-
-// Converts a left-to-right stream of bits to uint64.
-inline uint64_t StreamToBits(std::string str) {
-  std::reverse(str.begin(), str.end());
-  return std::bitset<64>(str).to_ullong();
-}
-
 // Converts first |num_bits| stored in uint64 to a left-to-right stream of bits.
 inline std::string BitsToStream(uint64_t bits, size_t num_bits = 64) {
   std::bitset<64> bitset(bits);
-  return BitsetToStream(bitset, num_bits);
+  std::string str = bitset.to_string().substr(64 - num_bits);
+  std::reverse(str.begin(), str.end());
+  return str;
 }
 
 // Base class for writing sequences of bits.
 class BitWriterInterface {
  public:
-  BitWriterInterface() {}
-  virtual ~BitWriterInterface() {}
+  BitWriterInterface() = default;
+  virtual ~BitWriterInterface() = default;
 
   // Writes lower |num_bits| in |bits| to the stream.
   // |num_bits| must be no greater than 64.
   virtual void WriteBits(uint64_t bits, size_t num_bits) = 0;
 
-  // Writes left-to-right string of '0' and '1' to stream.
-  // String length must be no greater than 64.
-  // Note: "01" will be writen as 0x2, not 0x1. The string doesn't represent
-  // numbers but a stream of bits in the order they come from encoder.
-  virtual void WriteStream(const std::string& bits) {
-    WriteBits(StreamToBits(bits), bits.length());
-  }
-
-  // Writes lower |num_bits| in |bits| to the stream.
-  // |num_bits| must be no greater than 64.
-  template <size_t N>
-  void WriteBitset(const std::bitset<N>& bits, size_t num_bits = N) {
-    WriteBits(bits.to_ullong(), num_bits);
-  }
-
   // Writes bits from value of type |T| to the stream. No encoding is done.
   // Always writes 8 * sizeof(T) bits.
   template <typename T>
@@ -237,27 +120,8 @@ class BitWriterInterface {
   void WriteVariableWidthU64(uint64_t val, size_t chunk_length);
   void WriteVariableWidthU32(uint32_t val, size_t chunk_length);
   void WriteVariableWidthU16(uint16_t val, size_t chunk_length);
-  void WriteVariableWidthU8(uint8_t val, size_t chunk_length);
   void WriteVariableWidthS64(int64_t val, size_t chunk_length,
                              size_t zigzag_exponent);
-  void WriteVariableWidthS32(int32_t val, size_t chunk_length,
-                             size_t zigzag_exponent);
-  void WriteVariableWidthS16(int16_t val, size_t chunk_length,
-                             size_t zigzag_exponent);
-  void WriteVariableWidthS8(int8_t val, size_t chunk_length,
-                            size_t zigzag_exponent);
-
-  // Writes |val| using fixed bit width. Bit width is determined by |max_val|:
-  // max_val 0 -> bit width 1
-  // max_val 1 -> bit width 1
-  // max_val 2 -> bit width 2
-  // max_val 3 -> bit width 2
-  // max_val 4 -> bit width 3
-  // max_val 5 -> bit width 3
-  // max_val 8 -> bit width 4
-  // max_val n -> bit width 1 + floor(log2(n))
-  // |val| needs to be <= |max_val|.
-  void WriteFixedWidth(uint64_t val, uint64_t max_val);
 
   // Returns number of bits written.
   virtual size_t GetNumBits() const = 0;
@@ -293,10 +157,6 @@ class BitWriterWord64 : public BitWriterInterface {
     return std::vector<uint8_t>(GetData(), GetData() + GetDataSizeBytes());
   }
 
-  // Returns written stream as std::string, padded with zeroes so that the
-  // length is a multiple of 64.
-  std::string GetStreamPadded64() const { return BufferToStream(buffer_); }
-
   // Sets callback to emit bit sequences after every write.
   void SetCallback(std::function<void(const std::string&)> callback) {
     callback_ = callback;
@@ -328,27 +188,6 @@ class BitReaderInterface {
   // Returns number of read bits. |num_bits| must be no greater than 64.
   virtual size_t ReadBits(uint64_t* bits, size_t num_bits) = 0;
 
-  // Reads |num_bits| from the stream, stores them in |bits|.
-  // Returns number of read bits. |num_bits| must be no greater than 64.
-  template <size_t N>
-  size_t ReadBitset(std::bitset<N>* bits, size_t num_bits = N) {
-    uint64_t val = 0;
-    size_t num_read = ReadBits(&val, num_bits);
-    if (num_read) {
-      *bits = std::bitset<N>(val);
-    }
-    return num_read;
-  }
-
-  // Reads |num_bits| from the stream, returns string in left-to-right order.
-  // The length of the returned string may be less than |num_bits| if end was
-  // reached.
-  std::string ReadStream(size_t num_bits) {
-    uint64_t bits = 0;
-    size_t num_read = ReadBits(&bits, num_bits);
-    return BitsToStream(bits, num_read);
-  }
-
   // Reads 8 * sizeof(T) bits and stores them in |val|.
   template <typename T>
   bool ReadUnencoded(T* val) {
@@ -383,19 +222,8 @@ class BitReaderInterface {
   bool ReadVariableWidthU64(uint64_t* val, size_t chunk_length);
   bool ReadVariableWidthU32(uint32_t* val, size_t chunk_length);
   bool ReadVariableWidthU16(uint16_t* val, size_t chunk_length);
-  bool ReadVariableWidthU8(uint8_t* val, size_t chunk_length);
   bool ReadVariableWidthS64(int64_t* val, size_t chunk_length,
                             size_t zigzag_exponent);
-  bool ReadVariableWidthS32(int32_t* val, size_t chunk_length,
-                            size_t zigzag_exponent);
-  bool ReadVariableWidthS16(int16_t* val, size_t chunk_length,
-                            size_t zigzag_exponent);
-  bool ReadVariableWidthS8(int8_t* val, size_t chunk_length,
-                           size_t zigzag_exponent);
-
-  // Reads value written by WriteFixedWidth (|max_val| needs to be the same).
-  // Returns true on success, false if the bit stream ends prematurely.
-  bool ReadFixedWidth(uint64_t* val, uint64_t max_val);
 
   BitReaderInterface(const BitReaderInterface&) = delete;
   BitReaderInterface& operator=(const BitReaderInterface&) = delete;
diff --git a/test/bit_stream.cpp b/test/bit_stream.cpp
index 16e4f20d..706b451d 100644
--- a/test/bit_stream.cpp
+++ b/test/bit_stream.cpp
@@ -25,12 +25,75 @@ namespace spvtools {
 namespace utils {
 namespace {
 
+// Converts |buffer| to a stream of '0' and '1'.
+template <typename T>
+std::string BufferToStream(const std::vector<T>& buffer) {
+  std::stringstream ss;
+  for (auto it = buffer.begin(); it != buffer.end(); ++it) {
+    std::string str = std::bitset<sizeof(T) * 8>(*it).to_string();
+    // Strings generated by std::bitset::to_string are read right to left.
+    // Reversing to left to right.
+    std::reverse(str.begin(), str.end());
+    ss << str;
+  }
+  return ss.str();
+}
+
+// Converts a left-to-right input string of '0' and '1' to a buffer of |T|
+// words.
+template <typename T>
+std::vector<T> StreamToBuffer(std::string str) {
+  // The input string is left-to-right, the input argument of std::bitset needs
+  // to right-to-left. Instead of reversing tokens, reverse the entire string
+  // and iterate tokens from end to begin.
+  std::reverse(str.begin(), str.end());
+  const int word_size = static_cast<int>(sizeof(T) * 8);
+  const int str_length = static_cast<int>(str.length());
+  std::vector<T> buffer;
+  buffer.reserve(NumBitsToNumWords<sizeof(T)>(str.length()));
+  for (int index = str_length - word_size; index >= 0; index -= word_size) {
+    buffer.push_back(static_cast<T>(
+        std::bitset<sizeof(T) * 8>(str, index, word_size).to_ullong()));
+  }
+  const size_t suffix_length = str.length() % word_size;
+  if (suffix_length != 0) {
+    buffer.push_back(static_cast<T>(
+        std::bitset<sizeof(T) * 8>(str, 0, suffix_length).to_ullong()));
+  }
+  return buffer;
+}
+
+// Adds '0' chars at the end of the string until the size is a multiple of N.
+template <size_t N>
+std::string PadToWord(std::string&& str) {
+  const size_t tail_length = str.size() % N;
+  if (tail_length != 0) str += std::string(N - tail_length, '0');
+  return std::move(str);
+}
+
+// Adds '0' chars at the end of the string until the size is a multiple of N.
+template <size_t N>
+std::string PadToWord(const std::string& str) {
+  return PadToWord<N>(std::string(str));
+}
+
+// Converts a left-to-right stream of bits to std::bitset.
+template <size_t N>
+std::bitset<N> StreamToBitset(std::string str) {
+  std::reverse(str.begin(), str.end());
+  return std::bitset<N>(str);
+}
+
+// Converts a left-to-right stream of bits to uint64.
+uint64_t StreamToBits(std::string str) {
+  std::reverse(str.begin(), str.end());
+  return std::bitset<64>(str).to_ullong();
+}
+
 // A simple and inefficient implementatition of BitWriterInterface,
 // using std::stringstream. Intended for tests only.
 class BitWriterStringStream : public BitWriterInterface {
  public:
-  void WriteStream(const std::string& bits) override { ss_ << bits; }
-
   void WriteBits(uint64_t bits, size_t num_bits) override {
     assert(num_bits <= 64);
     ss_ << BitsToStream(bits, num_bits);
@@ -73,52 +136,11 @@ class BitReaderFromString : public BitReaderInterface {
 
   bool ReachedEnd() const override { return pos_ >= str_.length(); }
 
-  const std::string& GetStreamPadded64() const { return str_; }
-
  private:
   std::string str_;
   size_t pos_;
 };
 
-TEST(Log2U16, Test) {
-  EXPECT_EQ(0u, Log2U64(0));
-  EXPECT_EQ(0u, Log2U64(1));
-  EXPECT_EQ(1u, Log2U64(2));
-  EXPECT_EQ(1u, Log2U64(3));
-  EXPECT_EQ(2u, Log2U64(4));
-  EXPECT_EQ(2u, Log2U64(5));
-  EXPECT_EQ(2u, Log2U64(6));
-  EXPECT_EQ(2u, Log2U64(7));
-  EXPECT_EQ(3u, Log2U64(8));
-  EXPECT_EQ(3u, Log2U64(9));
-  EXPECT_EQ(3u, Log2U64(10));
-  EXPECT_EQ(3u, Log2U64(11));
-  EXPECT_EQ(3u, Log2U64(12));
-  EXPECT_EQ(3u, Log2U64(13));
-  EXPECT_EQ(3u, Log2U64(14));
-  EXPECT_EQ(3u, Log2U64(15));
-  EXPECT_EQ(4u, Log2U64(16));
-  EXPECT_EQ(4u, Log2U64(17));
-  EXPECT_EQ(5u, Log2U64(35));
-  EXPECT_EQ(6u, Log2U64(72));
-  EXPECT_EQ(7u, Log2U64(255));
-  EXPECT_EQ(8u, Log2U64(256));
-  EXPECT_EQ(15u, Log2U64(65535));
-  EXPECT_EQ(16u, Log2U64(65536));
-  EXPECT_EQ(19u, Log2U64(0xFFFFF));
-  EXPECT_EQ(23u, Log2U64(0xFFFFFF));
-  EXPECT_EQ(27u, Log2U64(0xFFFFFFF));
-  EXPECT_EQ(31u, Log2U64(0xFFFFFFFF));
-  EXPECT_EQ(35u, Log2U64(0xFFFFFFFFF));
-  EXPECT_EQ(39u, Log2U64(0xFFFFFFFFFF));
-  EXPECT_EQ(43u, Log2U64(0xFFFFFFFFFFF));
-  EXPECT_EQ(47u, Log2U64(0xFFFFFFFFFFFF));
-  EXPECT_EQ(51u, Log2U64(0xFFFFFFFFFFFFF));
-  EXPECT_EQ(55u, Log2U64(0xFFFFFFFFFFFFFF));
-  EXPECT_EQ(59u, Log2U64(0xFFFFFFFFFFFFFFF));
-  EXPECT_EQ(63u, Log2U64(0xFFFFFFFFFFFFFFFF));
-}
-
 TEST(NumBitsToNumWords, Word8) {
   EXPECT_EQ(0u, NumBitsToNumWords<8>(0));
   EXPECT_EQ(1u, NumBitsToNumWords<8>(1));
@@ -141,34 +163,6 @@ TEST(NumBitsToNumWords, Word64) {
   EXPECT_EQ(3u, NumBitsToNumWords<64>(129));
 }
 
-TEST(ZigZagCoding, Encode) {
-  EXPECT_EQ(0u, EncodeZigZag(0));
-  EXPECT_EQ(1u, EncodeZigZag(-1));
-  EXPECT_EQ(2u, EncodeZigZag(1));
-  EXPECT_EQ(3u, EncodeZigZag(-2));
-  EXPECT_EQ(4u, EncodeZigZag(2));
-  EXPECT_EQ(5u, EncodeZigZag(-3));
-  EXPECT_EQ(6u, EncodeZigZag(3));
-  EXPECT_EQ(std::numeric_limits<uint64_t>::max() - 1,
-            EncodeZigZag(std::numeric_limits<int64_t>::max()));
-  EXPECT_EQ(std::numeric_limits<uint64_t>::max(),
-            EncodeZigZag(std::numeric_limits<int64_t>::min()));
-}
-
-TEST(ZigZagCoding, Decode) {
-  EXPECT_EQ(0, DecodeZigZag(0));
-  EXPECT_EQ(-1, DecodeZigZag(1));
-  EXPECT_EQ(1, DecodeZigZag(2));
-  EXPECT_EQ(-2, DecodeZigZag(3));
-  EXPECT_EQ(2, DecodeZigZag(4));
-  EXPECT_EQ(-3, DecodeZigZag(5));
-  EXPECT_EQ(3, DecodeZigZag(6));
-  EXPECT_EQ(std::numeric_limits<int64_t>::min(),
-            DecodeZigZag(std::numeric_limits<uint64_t>::max()));
-  EXPECT_EQ(std::numeric_limits<int64_t>::max(),
-            DecodeZigZag(std::numeric_limits<uint64_t>::max() - 1));
-}
-
 TEST(ZigZagCoding, Encode0) {
   EXPECT_EQ(0u, EncodeZigZag(0, 0));
   EXPECT_EQ(1u, EncodeZigZag(-1, 0));
@@ -191,18 +185,6 @@ TEST(ZigZagCoding, Decode0) {
             DecodeZigZag(std::numeric_limits<uint64_t>::max() - 1, 0));
 }
 
-TEST(ZigZagCoding, Decode0SameAsNormalZigZag) {
-  for (int32_t i = -10000; i < 10000; i += 123) {
-    ASSERT_EQ(DecodeZigZag(i), DecodeZigZag(i, 0));
-  }
-}
-
-TEST(ZigZagCoding, Encode0SameAsNormalZigZag) {
-  for (uint32_t i = 0; i < 10000; i += 123) {
-    ASSERT_EQ(EncodeZigZag(i), EncodeZigZag(i, 0));
-  }
-}
-
 TEST(ZigZagCoding, Encode1) {
   EXPECT_EQ(0u, EncodeZigZag(0, 1));
   EXPECT_EQ(1u, EncodeZigZag(1, 1));
@@ -428,30 +410,6 @@ TEST(BitWriterStringStream, Empty) {
   EXPECT_EQ("", writer.GetStreamRaw());
 }
 
-TEST(BitWriterStringStream, WriteStream) {
-  BitWriterStringStream writer;
-  const std::string bits1 = "1011111111111111111";
-  writer.WriteStream(bits1);
-  EXPECT_EQ(19u, writer.GetNumBits());
-  EXPECT_EQ(3u, writer.GetDataSizeBytes());
-  EXPECT_EQ(bits1, writer.GetStreamRaw());
-
-  const std::string bits2 = "10100001010101010000111111111111111111111111111";
-  writer.WriteStream(bits2);
-  EXPECT_EQ(66u, writer.GetNumBits());
-  EXPECT_EQ(9u, writer.GetDataSizeBytes());
-  EXPECT_EQ(bits1 + bits2, writer.GetStreamRaw());
-}
-
-TEST(BitWriterStringStream, WriteBitSet) {
-  BitWriterStringStream writer;
-  const std::string bits1 = "10101";
-  writer.WriteBitset(StreamToBitset<16>(bits1));
-  EXPECT_EQ(16u, writer.GetNumBits());
-  EXPECT_EQ(2u, writer.GetDataSizeBytes());
-  EXPECT_EQ(PadToWord<16>(bits1), writer.GetStreamRaw());
-}
-
 TEST(BitWriterStringStream, WriteBits) {
   BitWriterStringStream writer;
   const uint64_t bits1 = 0x1 | 0x2 | 0x10;
@@ -482,20 +440,19 @@ TEST(BitWriterStringStream, WriteMultiple) {
   BitWriterStringStream writer;
 
   std::string expected_result;
-  const std::string bits1 = "101001111111001100010000001110001111111100";
-  writer.WriteStream(bits1);
 
-  const std::string bits2 = "10100011000010010101";
-  writer.WriteBitset(StreamToBitset<20>(bits2));
+  const uint64_t b2_val = 0x4 | 0x2 | 0x40;
+  const std::string bits2 = BitsToStream(b2_val, 8);
+  writer.WriteBits(b2_val, 8);
 
   const uint64_t val = 0x1 | 0x2 | 0x10;
   const std::string bits3 = BitsToStream(val, 8);
   writer.WriteBits(val, 8);
 
-  const std::string expected = bits1 + bits2 + bits3;
+  const std::string expected = bits2 + bits3;
 
   EXPECT_EQ(expected.length(), writer.GetNumBits());
-  EXPECT_EQ(9u, writer.GetDataSizeBytes());
+  EXPECT_EQ(2u, writer.GetDataSizeBytes());
   EXPECT_EQ(expected, writer.GetStreamRaw());
 
   EXPECT_EQ(PadToWord<8>(expected), BufferToStream(writer.GetDataCopy()));
@@ -505,46 +462,6 @@ TEST(BitWriterWord64, Empty) {
   BitWriterWord64 writer;
   EXPECT_EQ(0u, writer.GetNumBits());
   EXPECT_EQ(0u, writer.GetDataSizeBytes());
-  EXPECT_EQ("", writer.GetStreamPadded64());
-}
-
-TEST(BitWriterWord64, WriteStream) {
-  BitWriterWord64 writer;
-  std::string expected;
-
-  {
-    const std::string bits = "101";
-    expected += bits;
-    writer.WriteStream(bits);
-    EXPECT_EQ(expected.length(), writer.GetNumBits());
-    EXPECT_EQ(1u, writer.GetDataSizeBytes());
-    EXPECT_EQ(PadToWord<64>(expected), writer.GetStreamPadded64());
-  }
-
-  {
-    const std::string bits = "10000111111111110000000";
-    expected += bits;
-    writer.WriteStream(bits);
-    EXPECT_EQ(expected.length(), writer.GetNumBits());
-    EXPECT_EQ(PadToWord<64>(expected), writer.GetStreamPadded64());
-  }
-
-  {
-    const std::string bits = "101001111111111100000111111111111100";
-    expected += bits;
-    writer.WriteStream(bits);
-    EXPECT_EQ(expected.length(), writer.GetNumBits());
-    EXPECT_EQ(PadToWord<64>(expected), writer.GetStreamPadded64());
-  }
-}
-
-TEST(BitWriterWord64, WriteBitset) {
-  BitWriterWord64 writer;
-  const std::string bits1 = "10101";
-  writer.WriteBitset(StreamToBitset<16>(bits1), 12);
-  EXPECT_EQ(12u, writer.GetNumBits());
-  EXPECT_EQ(2u, writer.GetDataSizeBytes());
-  EXPECT_EQ(PadToWord<64>(bits1), writer.GetStreamPadded64());
 }
 
 TEST(BitWriterWord64, WriteBits) {
@@ -555,7 +472,6 @@ TEST(BitWriterWord64, WriteBits) {
   writer.WriteBits(bits1, 5);
   EXPECT_EQ(15u, writer.GetNumBits());
   EXPECT_EQ(2u, writer.GetDataSizeBytes());
-  EXPECT_EQ(PadToWord<64>("110011100111001"), writer.GetStreamPadded64());
 }
 
 TEST(BitWriterWord64, WriteZeroBits) {
@@ -565,18 +481,11 @@ TEST(BitWriterWord64, WriteZeroBits) {
   EXPECT_EQ(0u, writer.GetNumBits());
   writer.WriteBits(1, 1);
   writer.WriteBits(0, 0);
-  EXPECT_EQ(PadToWord<64>("1"), writer.GetStreamPadded64());
   writer.WriteBits(0, 63);
   EXPECT_EQ(64u, writer.GetNumBits());
   writer.WriteBits(0, 0);
   writer.WriteBits(7, 3);
   writer.WriteBits(0, 0);
-  EXPECT_EQ(
-      PadToWord<64>(
-          "1"
-          "000000000000000000000000000000000000000000000000000000000000000"
-          "111"),
-      writer.GetStreamPadded64());
 }
 
 TEST(BitWriterWord64, ComparisonTestWriteLotsOfBits) {
@@ -588,42 +497,6 @@ TEST(BitWriterWord64, ComparisonTestWriteLotsOfBits) {
     writer2.WriteBits(i, 16);
     ASSERT_EQ(writer1.GetNumBits(), writer2.GetNumBits());
   }
-
-  EXPECT_EQ(PadToWord<64>(writer1.GetStreamRaw()), writer2.GetStreamPadded64());
-}
-
-TEST(BitWriterWord64, ComparisonTestWriteLotsOfStreams) {
-  BitWriterStringStream writer1;
-  BitWriterWord64 writer2(16384);
-
-  for (int i = 0; i < 1000; ++i) {
-    std::string bits = "1111100000";
-    if (i % 2) bits += "101010";
-    if (i % 3) bits += "1110100";
-    if (i % 5) bits += "1110100111111111111";
-    writer1.WriteStream(bits);
-    writer2.WriteStream(bits);
-    ASSERT_EQ(writer1.GetNumBits(), writer2.GetNumBits());
-  }
-
-  EXPECT_EQ(PadToWord<64>(writer1.GetStreamRaw()), writer2.GetStreamPadded64());
-}
-
-TEST(BitWriterWord64, ComparisonTestWriteLotsOfBitsets) {
-  BitWriterStringStream writer1;
-  BitWriterWord64 writer2(16384);
-
-  for (uint64_t i = 0; i < 65000; i += 25) {
-    std::bitset<16> bits1(i);
-    std::bitset<24> bits2(i);
-    writer1.WriteBitset(bits1);
-    writer1.WriteBitset(bits2);
-    writer2.WriteBitset(bits1);
-    writer2.WriteBitset(bits2);
-    ASSERT_EQ(writer1.GetNumBits(), writer2.GetNumBits());
-  }
-
-  EXPECT_EQ(PadToWord<64>(writer1.GetStreamRaw()), writer2.GetStreamPadded64());
 }
 
 TEST(GetLowerBits, Test) {
@@ -661,7 +534,6 @@ TEST(BitReaderFromString, FromU8) {
       "10111011";
 
   BitReaderFromString reader(buffer);
-  EXPECT_EQ(PadToWord<64>(total_stream), reader.GetStreamPadded64());
 
   uint64_t bits = 0;
   EXPECT_EQ(2u, reader.ReadBits(&bits, 2));
@@ -690,7 +562,6 @@ TEST(BitReaderFromString, FromU64) {
       "1011101110111011101110111011101110111011101110111011101110111011";
 
   BitReaderFromString reader(buffer);
-  EXPECT_EQ(total_stream, reader.GetStreamPadded64());
 
   uint64_t bits = 0;
   size_t pos = 0;
@@ -728,40 +599,6 @@ TEST(BitReaderWord64, ReadBitsSingleByte) {
   EXPECT_TRUE(reader.ReachedEnd());
 }
 
-TEST(BitReaderWord64, ReadBitsetSingleByte) {
-  BitReaderWord64 reader(std::vector<uint8_t>({uint8_t(0xCC)}));
-  std::bitset<4> bits;
-  EXPECT_EQ(2u, reader.ReadBitset(&bits, 2));
-  EXPECT_EQ(0u, bits.to_ullong());
-  EXPECT_EQ(2u, reader.ReadBitset(&bits, 2));
-  EXPECT_EQ(3u, bits.to_ullong());
-  EXPECT_FALSE(reader.OnlyZeroesLeft());
-  EXPECT_EQ(4u, reader.ReadBitset(&bits, 4));
-  EXPECT_EQ(12u, bits.to_ullong());
-  EXPECT_TRUE(reader.OnlyZeroesLeft());
-}
-
-TEST(BitReaderWord64, ReadStreamSingleByte) {
-  BitReaderWord64 reader(std::vector<uint8_t>({uint8_t(0xAA)}));
-  EXPECT_EQ("", reader.ReadStream(0));
-  EXPECT_EQ("0", reader.ReadStream(1));
-  EXPECT_EQ("101", reader.ReadStream(3));
-  EXPECT_EQ("01010000", reader.ReadStream(8));
-  EXPECT_TRUE(reader.OnlyZeroesLeft());
-  EXPECT_EQ("0000000000000000000000000000000000000000000000000000",
-            reader.ReadStream(64));
-  EXPECT_TRUE(reader.ReachedEnd());
-}
-
-TEST(BitReaderWord64, ReadStreamEmpty) {
-  std::vector<uint64_t> buffer;
-  BitReaderWord64 reader(std::move(buffer));
-  EXPECT_TRUE(reader.OnlyZeroesLeft());
-  EXPECT_TRUE(reader.ReachedEnd());
-  EXPECT_EQ("", reader.ReadStream(10));
-  EXPECT_TRUE(reader.ReachedEnd());
-}
-
 TEST(BitReaderWord64, ReadBitsTwoWords) {
   std::vector<uint64_t> buffer = {0x0000000000000001, 0x0000000000FFFFFF};
 
@@ -934,37 +771,6 @@ TEST(VariableWidthWrite, Write0U) {
       "000"
       "000",
       writer.GetStreamRaw());
-  writer.WriteVariableWidthU8(0, 2);
-  EXPECT_EQ(
-      "000"
-      "000"
-      "000"
-      "000",
-      writer.GetStreamRaw());
-}
-
-TEST(VariableWidthWrite, Write0S) {
-  BitWriterStringStream writer;
-  writer.WriteVariableWidthS64(0, 2, 0);
-  EXPECT_EQ("000", writer.GetStreamRaw());
-  writer.WriteVariableWidthS32(0, 2, 0);
-  EXPECT_EQ(
-      "000"
-      "000",
-      writer.GetStreamRaw());
-  writer.WriteVariableWidthS16(0, 2, 0);
-  EXPECT_EQ(
-      "000"
-      "000"
-      "000",
-      writer.GetStreamRaw());
-  writer.WriteVariableWidthS8(0, 2, 0);
-  EXPECT_EQ(
-      "000"
-      "000"
-      "000"
-      "000",
-      writer.GetStreamRaw());
 }
 
 TEST(VariableWidthWrite, WriteSmallUnsigned) {
@@ -982,13 +788,6 @@ TEST(VariableWidthWrite, WriteSmallUnsigned) {
       "010"
       "110",
       writer.GetStreamRaw());
-  writer.WriteVariableWidthU8(4, 2);
-  EXPECT_EQ(
-      "100"
-      "010"
-      "110"
-      "001100",
-      writer.GetStreamRaw());
 }
 
 TEST(VariableWidthWrite, WriteSmallSigned) {
@@ -1000,19 +799,6 @@ TEST(VariableWidthWrite, WriteSmallSigned) {
       "010"
       "100",
       writer.GetStreamRaw());
-  writer.WriteVariableWidthS16(3, 2, 0);
-  EXPECT_EQ(
-      "010"
-      "100"
-      "011100",
-      writer.GetStreamRaw());
-  writer.WriteVariableWidthS8(-4, 2, 0);
-  EXPECT_EQ(
-      "010"
-      "100"
-      "011100"
-      "111100",
-      writer.GetStreamRaw());
 }
 
 TEST(VariableWidthWrite, U64Val127ChunkLength7) {
@@ -1044,16 +830,6 @@ TEST(VariableWidthWrite, U16Val2ChunkLength4) {
       writer.GetStreamRaw());
 }
 
-TEST(VariableWidthWrite, U8Val128ChunkLength7) {
-  BitWriterStringStream writer;
-  writer.WriteVariableWidthU8(128, 7);
-  EXPECT_EQ(
-      "0000000"
-      "1"
-      "1",
-      writer.GetStreamRaw());
-}
-
 TEST(VariableWidthWrite, U64ValAAAAChunkLength2) {
   BitWriterStringStream writer;
   writer.WriteVariableWidthU64(0xAAAA, 2);
@@ -1077,16 +853,6 @@ TEST(VariableWidthWrite, U64ValAAAAChunkLength2) {
       writer.GetStreamRaw());
 }
 
-TEST(VariableWidthWrite, S8ValM128ChunkLength7) {
-  BitWriterStringStream writer;
-  writer.WriteVariableWidthS8(-128, 7, 0);
-  EXPECT_EQ(
-      "1111111"
-      "1"
-      "1",
-      writer.GetStreamRaw());
-}
-
 TEST(VariableWidthRead, U64Val127ChunkLength7) {
   BitReaderFromString reader(
       "1111111"
@@ -1116,16 +882,6 @@ TEST(VariableWidthRead, U16Val2ChunkLength4) {
   EXPECT_EQ(2u, val);
 }
 
-TEST(VariableWidthRead, U8Val128ChunkLength7) {
-  BitReaderFromString reader(
-      "0000000"
-      "1"
-      "1");
-  uint8_t val = 0;
-  ASSERT_TRUE(reader.ReadVariableWidthU8(&val, 7));
-  EXPECT_EQ(128u, val);
-}
-
 TEST(VariableWidthRead, U64ValAAAAChunkLength2) {
   BitReaderFromString reader(
       "01"
@@ -1149,16 +905,6 @@ TEST(VariableWidthRead, U64ValAAAAChunkLength2) {
   EXPECT_EQ(0xAAAAu, val);
 }
 
-TEST(VariableWidthRead, S8ValM128ChunkLength7) {
-  BitReaderFromString reader(
-      "1111111"
-      "1"
-      "1");
-  int8_t val = 0;
-  ASSERT_TRUE(reader.ReadVariableWidthS8(&val, 7, 0));
-  EXPECT_EQ(-128, val);
-}
-
 TEST(VariableWidthRead, FailTooShort) {
   BitReaderFromString reader("00000001100000");
   uint64_t val = 0;
@@ -1215,24 +961,6 @@ TEST(VariableWidthWriteRead, SingleWriteReadU32) {
   }
 }
 
-TEST(VariableWidthWriteRead, SingleWriteReadS32) {
-  for (int32_t i = 0; i < 100000; i += 123) {
-    const int32_t val = i * (i % 2 ? -i : i);
-    const size_t chunk_length = i % 16 + 1;
-    const size_t zigzag_exponent = i % 11;
-
-    BitWriterWord64 writer;
-    writer.WriteVariableWidthS32(val, chunk_length, zigzag_exponent);
-
-    BitReaderWord64 reader(writer.GetDataCopy());
-    int32_t read_val = 0;
-    ASSERT_TRUE(
-        reader.ReadVariableWidthS32(&read_val, chunk_length, zigzag_exponent));
-
-    ASSERT_EQ(val, read_val) << "Chunk length " << chunk_length;
-  }
-}
-
 TEST(VariableWidthWriteRead, SingleWriteReadU16) {
   for (int i = 0; i < 65536; i += 123) {
     const uint16_t val = static_cast<int16_t>(i);
@@ -1249,58 +977,6 @@ TEST(VariableWidthWriteRead, SingleWriteReadU16) {
   }
 }
 
-TEST(VariableWidthWriteRead, SingleWriteReadS16) {
-  for (int i = -32768; i < 32768; i += 123) {
-    const int16_t val = static_cast<int16_t>(i);
-    const size_t chunk_length = std::abs(i) % 10 + 1;
-    const size_t zigzag_exponent = std::abs(i) % 7;
-
-    BitWriterWord64 writer;
-    writer.WriteVariableWidthS16(val, chunk_length, zigzag_exponent);
-
-    BitReaderWord64 reader(writer.GetDataCopy());
-    int16_t read_val = 0;
-    ASSERT_TRUE(
-        reader.ReadVariableWidthS16(&read_val, chunk_length, zigzag_exponent));
-
-    ASSERT_EQ(val, read_val) << "Chunk length " << chunk_length;
-  }
-}
-
-TEST(VariableWidthWriteRead, SingleWriteReadU8) {
-  for (int i = 0; i < 256; ++i) {
-    const uint8_t val = static_cast<uint8_t>(i);
-    const size_t chunk_length = val % 5 + 1;
-
-    BitWriterWord64 writer;
-    writer.WriteVariableWidthU8(val, chunk_length);
-
-    BitReaderWord64 reader(writer.GetDataCopy());
-    uint8_t read_val = 0;
-    ASSERT_TRUE(reader.ReadVariableWidthU8(&read_val, chunk_length));
-
-    ASSERT_EQ(val, read_val) << "Chunk length " << chunk_length;
-  }
-}
-
-TEST(VariableWidthWriteRead, SingleWriteReadS8) {
-  for (int i = -128; i < 128; ++i) {
-    const int8_t val = static_cast<int8_t>(i);
-    const size_t chunk_length = std::abs(i) % 5 + 1;
-    const size_t zigzag_exponent = std::abs(i) % 3;
-
-    BitWriterWord64 writer;
-    writer.WriteVariableWidthS8(val, chunk_length, zigzag_exponent);
-
-    BitReaderWord64 reader(writer.GetDataCopy());
-    int8_t read_val = 0;
-    ASSERT_TRUE(
-        reader.ReadVariableWidthS8(&read_val, chunk_length, zigzag_exponent));
-
-    ASSERT_EQ(val, read_val) << "Chunk length " << chunk_length;
-  }
-}
-
 TEST(VariableWidthWriteRead, SmallNumbersChunkLength4) {
   const std::vector<uint64_t> expected_values = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
 
@@ -1344,70 +1020,6 @@ TEST(VariableWidthWriteRead, VariedNumbersChunkLength8) {
   EXPECT_EQ(expected_values, actual_values);
 }
 
-TEST(FixedWidthWrite, Val0Max3) {
-  BitWriterStringStream writer;
-  writer.WriteFixedWidth(0, 3);
-  EXPECT_EQ("00", writer.GetStreamRaw());
-}
-
-TEST(FixedWidthWrite, Val0Max5) {
-  BitWriterStringStream writer;
-  writer.WriteFixedWidth(0, 5);
-  EXPECT_EQ("000", writer.GetStreamRaw());
-}
-
-TEST(FixedWidthWrite, Val0Max255) {
-  BitWriterStringStream writer;
-  writer.WriteFixedWidth(0, 255);
-  EXPECT_EQ("00000000", writer.GetStreamRaw());
-}
-
-TEST(FixedWidthWrite, Val3Max8) {
-  BitWriterStringStream writer;
-  writer.WriteFixedWidth(3, 8);
-  EXPECT_EQ("1100", writer.GetStreamRaw());
-}
-
-TEST(FixedWidthWrite, Val15Max127) {
-  BitWriterStringStream writer;
-  writer.WriteFixedWidth(15, 127);
-  EXPECT_EQ("1111000", writer.GetStreamRaw());
-}
-
-TEST(FixedWidthRead, Val0Max3) {
-  BitReaderFromString reader("0011111");
-  uint64_t val = 0;
-  ASSERT_TRUE(reader.ReadFixedWidth(&val, 3));
-  EXPECT_EQ(0u, val);
-}
-
-TEST(FixedWidthRead, Val0Max5) {
-  BitReaderFromString reader("0001010101");
-  uint64_t val = 0;
-  ASSERT_TRUE(reader.ReadFixedWidth(&val, 5));
-  EXPECT_EQ(0u, val);
-}
-
-TEST(FixedWidthRead, Val3Max8) {
-  BitReaderFromString reader("11001010101");
-  uint64_t val = 0;
-  ASSERT_TRUE(reader.ReadFixedWidth(&val, 8));
-  EXPECT_EQ(3u, val);
-}
-
-TEST(FixedWidthRead, Val15Max127) {
-  BitReaderFromString reader("111100010101");
-  uint64_t val = 0;
-  ASSERT_TRUE(reader.ReadFixedWidth(&val, 127));
-  EXPECT_EQ(15u, val);
-}
-
-TEST(FixedWidthRead, Fail) {
-  BitReaderFromString reader("111100");
-  uint64_t val = 0;
-  ASSERT_FALSE(reader.ReadFixedWidth(&val, 127));
-}
-
 }  // namespace
 }  // namespace utils
 }  // namespace spvtools