Roll forward to cl/338482889

Signed-off-by: Alexey Polyudov <apolyudov@google.com>
Change-Id: I9850950db8bd84f0904ea1a413151887f52098cf

cpp/platform/base/base_input_stream.h

@@ -0,0 +1,43 @@
+#ifndef PLATFORM_BASE_BASE_INPUT_STREAM_H_
+#define PLATFORM_BASE_BASE_INPUT_STREAM_H_
+
+#include "platform/base/byte_array.h"
+#include "platform/base/exception.h"
+#include "platform/base/input_stream.h"
+
+namespace location {
+namespace nearby {
+
+// A base {@link InputStream } for reading the contents of a byte array.
+class BaseInputStream : public InputStream {
+ public:
+  explicit BaseInputStream(ByteArray &buffer) : buffer_{buffer} {}
+  BaseInputStream(const BaseInputStream &) = delete;
+  BaseInputStream &operator=(const BaseInputStream &) = delete;
+  ~BaseInputStream() override { Close(); }
+
+  ExceptionOr<ByteArray> Read(std::int64_t size) override;
+
+  Exception Close() override {
+    // Do nothing.
+    return {Exception::kSuccess};
+  }
+
+  std::uint8_t ReadUint8();
+  std::uint16_t ReadUint16();
+  std::uint32_t ReadUint32();
+  std::uint64_t ReadUint64();
+  ByteArray ReadBytes(int size);
+  bool IsAvailable(int size) const {
+    return buffer_.size() - position_ >= size;
+  }
+
+ private:
+  ByteArray &buffer_;
+  int position_{0};
+};
+
+}  // namespace nearby
+}  // namespace location
+
+#endif  // PLATFORM_BASE_BASE_INPUT_STREAM_H_