diff --git a/include/dmlc/base.h b/include/dmlc/base.h
new file mode 100644
index 000000000..89218b4a9
--- /dev/null
+++ b/include/dmlc/base.h
@@ -0,0 +1,106 @@
+/*!
+ *  Copyright (c) 2015 by Contributors
+ * \file base.h
+ * \brief defines configuration macros
+ */
+#ifndef DMLC_BASE_H_
+#define DMLC_BASE_H_
+
+/*! \brief whether use glog for logging*/
+#ifndef DMLC_USE_GLOG
+#define DMLC_USE_GLOG 0
+#endif
+
+/*! \brief whether compile with hdfs support */
+#ifndef DMLC_USE_HDFS
+#define DMLC_USE_HDFS 0
+#endif
+
+/*! \brief whether compile with s3 support */
+#ifndef DMLC_USE_S3
+#define DMLC_USE_S3 0
+#endif
+
+/*! \brief whether or not use parameter server */
+#ifndef DMLC_USE_PS
+#define DMLC_USE_PS 0
+#endif
+
+/*! \brief whether or not use c++11 support */
+#ifndef DMLC_USE_CXX11
+#define DMLC_USE_CXX11 defined(__GXX_EXPERIMENTAL_CXX0X) || __cplusplus >= 201103L || defined(_MSC_VER)
+#endif
+
+///
+/// code block to handle optionally loading
+///
+#if !defined(__GNUC__)
+#define fopen64 std::fopen
+#endif
+#ifdef _MSC_VER
+// NOTE: sprintf_s is not equivalent to snprintf,
+// they are equivalent when success, which is sufficient for our case
+#define snprintf sprintf_s
+#define vsnprintf vsprintf_s
+#else
+#ifdef _FILE_OFFSET_BITS
+#if _FILE_OFFSET_BITS == 32
+#pragma message ("Warning: FILE OFFSET BITS defined to be 32 bit")
+#endif
+#endif
+
+#ifdef __APPLE__
+#define off64_t off_t
+#define fopen64 std::fopen
+#endif
+
+extern "C" {
+#include <sys/types.h>
+}
+#endif
+
+#ifdef _MSC_VER
+typedef unsigned __int16 uint16_t;
+typedef unsigned __int32 uint32_t;
+typedef unsigned __int64 uint64_t;
+typedef __int64 int64_t;
+#else
+#include <inttypes.h>
+#endif
+#include <vector>
+#include <string>
+
+/*! \brief namespace for dmlc */
+namespace dmlc {
+/*!
+ * \brief safely get the beginning address of a vector
+ * \param vec input vector
+ * \return beginning address of a vector
+ */
+template<typename T>
+inline T *BeginPtr(std::vector<T> &vec) {
+  if (vec.size() == 0) {
+    return NULL;
+  } else {
+    return &vec[0];
+  }
+}
+/*! \brief get the beginning address of a vector */
+template<typename T>
+inline const T *BeginPtr(const std::vector<T> &vec) {
+  if (vec.size() == 0) {
+    return NULL;
+  } else {
+    return &vec[0];
+  }
+}
+inline char* BeginPtr(std::string &str) {
+  if (str.length() == 0) return NULL;
+  return &str[0];
+}
+inline const char* BeginPtr(const std::string &str) {
+  if (str.length() == 0) return NULL;
+  return &str[0];
+}
+}  // namespace dmlc
+#endif  // DMLC_BASE_H_
diff --git a/include/dmlc/io.h b/include/dmlc/io.h
index 017181c54..041d6dd36 100644
--- a/include/dmlc/io.h
+++ b/include/dmlc/io.h
@@ -11,6 +11,7 @@
 #include <istream>
 #include <ostream>
 #include <streambuf>
+#include "./base.h"
 
 /*! \brief namespace for dmlc */
 namespace dmlc {
@@ -128,12 +129,25 @@ class InputSplit {
     /*! \brief size of the memory region */
     size_t size;
   };
+  /*!
+   * \brief hint the inputsplit how large the chunk size
+   *  it should return when implementing NextChunk
+   *  this is a hint so may not be enforced,
+   *  but InputSplit will try adjust its internal buffer
+   *  size to the hinted value
+   * \param chunk_size the chunk size 
+   */
+  virtual void HintChunkSize(size_t chunk_size) {}
   /*! \brief reset the position of InputSplit to beginning */
   virtual void BeforeFirst(void) = 0;
   /*!
    * \brief get the next record, the returning value
    *   is valid until next call to NextRecord or NextChunk
    *   caller can modify the memory content of out_rec
+   *   
+   *   For text, out_rec contains a single line
+   *   For recordio, out_rec contains one record content(with header striped)
+   *
    * \param out_rec used to store the result
    * \return true if we can successfully get next record
    *     false if we reached end of split
@@ -144,7 +158,7 @@ class InputSplit {
    * \brief get a chunk of memory that can contain multiple records, 
    *  the caller needs to parse the content of the resulting chunk,
    *  for text file, out_chunk can contain data of multiple lines
-   *  for recordio, out_chunk can contain data of multiple records
+   *  for recordio, out_chunk can contain multiple records(including headers)
    *   
    *  This function ensures there won't be partial record in the chunk
    *  caller can modify the memory content of out_chunk,
@@ -157,6 +171,7 @@ class InputSplit {
    * \return true if we can successfully get next record
    *     false if we reached end of split
    * \sa InputSplit::Create for definition of record
+   * \sa RecordIOChunkReader to parse recordio content from out_chunk
    */
   virtual bool NextChunk(Blob *out_chunk) = 0;
   /*! \brief destructor*/