1 files changed, 76 insertions, 0 deletions
diff --git a/klm/util/stream/io.hh b/klm/util/stream/io.hh
new file mode 100644
index 00000000..934b6b3f
--- /dev/null
+++ b/klm/util/stream/io.hh
@@ -0,0 +1,76 @@
+#ifndef UTIL_STREAM_IO__
+#define UTIL_STREAM_IO__
+
+#include "util/exception.hh"
+#include "util/file.hh"
+
+namespace util {
+namespace stream {
+
+class ChainPosition;
+
+class ReadSizeException : public util::Exception {
+  public:
+    ReadSizeException() throw();
+    ~ReadSizeException() throw();
+};
+
+class Read {
+  public:
+    explicit Read(int fd) : file_(fd) {}
+    void Run(const ChainPosition &position); 
+  private:
+    int file_;
+};
+
+// Like read but uses pread so that the file can be accessed from multiple threads.  
+class PRead {
+  public:
+    explicit PRead(int fd, bool take_own = false) : file_(fd), own_(take_own) {}
+    void Run(const ChainPosition &position);
+  private:
+    int file_;
+    bool own_;
+};
+
+class Write {
+  public:
+    explicit Write(int fd) : file_(fd) {}
+    void Run(const ChainPosition &position);
+  private:
+    int file_;
+};
+
+class WriteAndRecycle {
+  public:
+    explicit WriteAndRecycle(int fd) : file_(fd) {}
+    void Run(const ChainPosition &position);
+  private:
+    int file_;
+};
+
+// Reuse the same file over and over again to buffer output.  
+class FileBuffer {
+  public:
+    explicit FileBuffer(int fd) : file_(fd) {}
+
+    WriteAndRecycle Sink() const {
+      util::SeekOrThrow(file_.get(), 0);
+      return WriteAndRecycle(file_.get());
+    }
+
+    PRead Source() const {
+      return PRead(file_.get());
+    }
+
+    uint64_t Size() const {
+      return SizeOrThrow(file_.get());
+    }
+
+  private:
+    scoped_fd file_;
+};
+
+} // namespace stream
+} // namespace util
+#endif // UTIL_STREAM_IO__