1 files changed, 88 insertions, 0 deletions
diff --git a/include/cru/common/io/AutoReadStream.h b/include/cru/common/io/AutoReadStream.h
new file mode 100644
index 00000000..7857e8b9
--- /dev/null
+++ b/include/cru/common/io/AutoReadStream.h
@@ -0,0 +1,88 @@
+#pragma once
+
+#include "Stream.h"
+#include "../Buffer.h"
+
+#include <condition_variable>
+#include <list>
+#include <mutex>
+#include <thread>
+#include <vector>
+
+namespace cru::io {
+struct AutoReadStreamOptions {
+  /**
+   * @brief The size of a single buffer allocated each time new space is needed.
+   * Use default value if <= 0.
+   *
+   * When current buffer is full and there is no space for following data, a new
+   * buffer will be allocated and appended to the buffer list. Note if sum size
+   * of all buffers reaches the total_buffer_size, no more buffer will be
+   * allocated but wait.
+   */
+  int buffer_block_size = 0;
+
+  /**
+   * @brief Total size limit of saved data in buffer. Use default value if < 0.
+   * No limit if == 0.
+   *
+   * When the buffer is filled, it will block and wait for user to read to get
+   * free space of buffer to continue read.
+   */
+  int total_buffer_size = 0;
+};
+
+/**
+ * @brief A stream that wraps another stream and auto read it into a buffer in a
+ * background thread.
+ */
+class CRU_BASE_API AutoReadStream : public Stream {
+ private:
+   class BufferBlock {
+     
+   };
+
+ public:
+  /**
+   * @brief Wrap a stream and auto read it in background.
+   * @param stream The stream to auto read.
+   * @param auto_delete Whether to delete the stream object in destructor.
+   * @param options Options to modify the behavior.
+   */
+  AutoReadStream(
+      Stream* stream, bool auto_delete,
+      const AutoReadStreamOptions& options = AutoReadStreamOptions());
+
+  ~AutoReadStream() override;
+
+ public:
+  bool CanSeek() override;
+  Index Seek(Index offset, SeekOrigin origin = SeekOrigin::Current) override;
+
+  bool CanRead() = 0;
+  virtual Index Read(std::byte* buffer, Index offset, Index size) = 0;
+
+  bool CanWrite() override;
+  Index Write(const std::byte* buffer, Index offset, Index size) override;
+
+  void Flush() override;
+
+  void Close() = 0;
+
+ private:
+  void BackgroundThreadRun();
+
+ private:
+  Stream* stream_;
+  bool auto_delete_;
+
+  int buffer_block_size_;
+  int total_buffer_size_;
+
+  std::mutex buffer_mutex_;
+  std::condition_variable buffer_condition_variable_;
+  std::list<Buffer> buffer_list_;
+
+  std::thread background_thread_;
+};
+}  // namespace cru::io