2 files changed, 15 insertions, 7 deletions

diff --git a/src/input-reader.cpp b/src/input-reader.cpp
index 2f10530..f1df3bf 100644
--- a/src/input-reader.cpp
+++ b/src/input-reader.cpp
@@ -13,6 +13,12 @@
 InputReader::InputReader(std::istream * stream, std::size_t block_size_bytes)
     : stream_(stream), block_size_bytes_(block_size_bytes)
 {
+    if (stream == nullptr) {
+        throw std::runtime_error("valid stream is required");
+    }
+    if (block_size_bytes == 0) {
+        throw std::runtime_error("block size in bytes must be positive");
+    }
 }
 
 SyncInputReader::SyncInputReader(std::istream * stream, std::size_t block_size_bytes)
@@ -54,9 +60,6 @@ SyncInputReader::GetBuffer()
 AsyncInputReader::AsyncInputReader(std::istream * stream, std::size_t block_size_bytes)
     : InputReader(stream, block_size_bytes)
 {
-    if (block_size_bytes == 0) {
-        throw std::runtime_error("block size in bytes must be positive");
-    }
     this->buffer_ = new char[block_size_bytes];
     assert(this->buffer_ != nullptr);
     this->bytes_in_buffer_ = 0;
@@ -161,4 +164,4 @@ AsyncInputReader::GetBuffer()
     std::vector<char> wrapper(this->buffer_, this->buffer_ + this->bytes_in_buffer_);
     this->bytes_in_buffer_ = 0;
     return wrapper;
-}
\ No newline at end of file
+}
diff --git a/src/input-reader.hpp b/src/input-reader.hpp
index aac2640..3a98ef8 100644
--- a/src/input-reader.hpp
+++ b/src/input-reader.hpp
@@ -21,6 +21,8 @@ protected:
     std::istream * const stream_;
     const std::size_t block_size_bytes_;
 
+    virtual std::vector<char> GetBuffer() = 0;
+
 public:
     InputReader() = delete;
     InputReader(const InputReader&) = delete;
@@ -32,19 +34,20 @@ public:
 
     virtual bool ReachedEOF() const = 0;
     virtual std::optional<std::vector<char>> GetBlock() = 0;
-    virtual std::vector<char> GetBuffer() = 0;
 };
 
 /*
  * Synchronous input reader
  */
 class SyncInputReader : public InputReader {
+protected:
+    std::vector<char> GetBuffer() override;
+
 public:
     SyncInputReader(std::istream * stream, std::size_t block_size_bytes);
 
     bool ReachedEOF() const override;
     std::optional<std::vector<char>> GetBlock() override;
-    std::vector<char> GetBuffer() override;
 };
 
 /*
@@ -65,13 +68,15 @@ private:
 
     void Read();
 
+protected:
+    std::vector<char> GetBuffer() override;
+
 public:
     AsyncInputReader(std::istream * stream, std::size_t block_size_bytes);
     ~AsyncInputReader() override;
 
     bool ReachedEOF() const override;
     std::optional<std::vector<char>> GetBlock() override;
-    std::vector<char> GetBuffer() override;
 };
 
 #endif