Repo created

libs/coding/reader_streambuf.hpp

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+#pragma once
+
+#include <cstdint>
+#include <iostream>
+#include <memory>
+
+class Reader;
+class Writer;
+
+class BaseStreamBuf : public std::streambuf
+{
+public:
+  typedef std::streambuf::traits_type traits_type;
+  typedef std::streambuf::char_type char_type;
+  typedef std::streambuf::int_type int_type;
+};
+
+class ReaderStreamBuf : public BaseStreamBuf
+{
+public:
+  ReaderStreamBuf(std::unique_ptr<Reader> && p);
+  virtual ~ReaderStreamBuf();
+
+private:
+  virtual std::streamsize xsgetn(char_type * s, std::streamsize n);
+  virtual int_type underflow();
+
+  std::unique_ptr<Reader> m_p;
+  uint64_t m_pos = 0;
+  uint64_t m_size = 0;
+  char m_buf[1] = {};
+};
+
+class WriterStreamBuf : public BaseStreamBuf
+{
+  Writer & m_writer;
+
+public:
+  /// Takes the ownership of p. Writer should be allocated in dynamic memory.
+  explicit WriterStreamBuf(Writer & writer) : m_writer(writer) {}
+
+private:
+  virtual std::streamsize xsputn(char_type const * s, std::streamsize n);
+  virtual int_type overflow(int_type c);
+  virtual int sync();
+};