[Base] Added ReadOnly BitStream

Author: Gliniak

src/xenia/base/bit_stream.cc

@@ -20,6 +20,9 @@ namespace xe {
 BitStream::BitStream(uint8_t* buffer, size_t size_in_bits)
     : buffer_(buffer), size_bits_(size_in_bits) {}
 
+BitStream::BitStream(const uint8_t* buffer, size_t size_in_bits)
+    : buffer_(const_cast<uint8_t*>(buffer)), size_bits_(size_in_bits) {}
+
 BitStream::~BitStream() = default;
 
 void BitStream::SetOffset(size_t offset_bits) {

src/xenia/base/bit_stream.h

@@ -18,6 +18,7 @@ namespace xe {
 class BitStream {
  public:
   BitStream(uint8_t* buffer, size_t size_in_bits);
+  BitStream(const uint8_t* buffer, size_t size_in_bits);
   ~BitStream();
 
   const uint8_t* buffer() const { return buffer_; }