Merge commit '57b5d7873f4f0953357e9d98e9c60cff8373d7ec'

subtree/rabit/rabit-learn/io/buffer_reader-inl.h

@@ -0,0 +1,57 @@
+#ifndef RABIT_LEARN_IO_BUFFER_READER_INL_H_
+#define RABIT_LEARN_IO_BUFFER_READER_INL_H_
+/*!
+ * \file buffer_reader-inl.h
+ * \brief implementation of stream buffer reader
+ * \author Tianqi Chen
+ */
+#include "./io.h"
+
+namespace rabit {
+namespace io {
+/*! \brief buffer reader of the stream that allows you to get */
+class StreamBufferReader {
+ public:
+  StreamBufferReader(size_t buffer_size)
+      :stream_(NULL),
+       read_len_(1), read_ptr_(1) {
+    buffer_.resize(buffer_size);
+  }
+  /*!
+   * \brief set input stream
+   */
+  inline void set_stream(IStream *stream) {
+    stream_ = stream;
+    read_len_ = read_ptr_ = 1;
+  }
+  /*!
+   * \brief allows quick read using get char
+   */
+  inline char GetChar(void) {
+    while (true) {
+      if (read_ptr_ < read_len_) {
+        return buffer_[read_ptr_++];
+      } else {
+        read_len_ = stream_->Read(&buffer_[0], buffer_.length());
+        if (read_len_ == 0) return EOF;
+        read_ptr_ = 0;
+      }
+    }
+  }
+  inline bool AtEnd(void) const {
+    return read_len_ == 0;
+  }
+  
+ private:
+  /*! \brief the underlying stream */
+  IStream *stream_;
+  /*! \brief buffer to hold data */
+  std::string buffer_;
+  /*! \brief length of valid data in buffer */
+  size_t read_len_;
+  /*! \brief pointer in the buffer */
+  size_t read_ptr_;
+};
+}  // namespace io
+}  // namespace rabit
+#endif  // RABIT_LEARN_IO_BUFFER_READER_INL_H_