diff --git a/mert/FileStream.cpp b/mert/FileStream.cpp
index 93b7138b2..1a52e53fa 100644
--- a/mert/FileStream.cpp
+++ b/mert/FileStream.cpp
@@ -1,7 +1,7 @@
 #include "FileStream.h"
 
 #include <stdexcept>
-#include "gzfilebuf.h"
+#include "GzFileBuf.h"
 
 using namespace std;
 
@@ -22,7 +22,7 @@ inputfilestream::inputfilestream(const std::string &filePath)
   if (IsGzipFile(filePath)) {
     fb->close();
     delete fb;
-    m_streambuf = new gzfilebuf(filePath.c_str());
+    m_streambuf = new GzFileBuf(filePath.c_str());
   } else {
     m_streambuf = fb;
   }
diff --git a/mert/GzFileBuf.h b/mert/GzFileBuf.h
new file mode 100644
index 000000000..c8a98aecf
--- /dev/null
+++ b/mert/GzFileBuf.h
@@ -0,0 +1,89 @@
+#ifndef MERT_GZFILEBUF_H_
+#define MERT_GZFILEBUF_H_
+
+#include <streambuf>
+#include <zlib.h>
+#include <cstring>
+
+class GzFileBuf : public std::streambuf
+{
+public:
+  explicit GzFileBuf(const char *filename) {
+    m_gz_file = gzopen(filename, "rb");
+    setg(m_buf + sizeof(int),     // beginning of putback area
+         m_buf + sizeof(int),     // read position
+         m_buf + sizeof(int));    // end position
+  }
+
+  virtual ~GzFileBuf() {
+    gzclose(m_gz_file);
+  }
+
+protected:
+  virtual int_type overflow(int_type c) {
+    throw;
+  }
+
+  // write multiple characters
+  virtual std::streamsize xsputn(const char* s,
+                                 std::streamsize num) {
+    throw;
+  }
+
+  virtual std::streampos seekpos(
+      std::streampos sp,
+      std::ios_base::openmode which = std::ios_base::in | std::ios_base::out) {
+    throw;
+  }
+
+  // read one character
+  virtual int_type underflow() {
+    // is read position before end of m_buf?
+    if (gptr() < egptr()) {
+      return traits_type::to_int_type(*gptr());
+    }
+
+    /* process size of putback area
+     * - use number of characters read
+     * - but at most four
+     */
+    unsigned int num_put_back = gptr() - eback();
+    if (num_put_back > sizeof(int)) {
+      num_put_back = sizeof(int);
+    }
+
+    /* copy up to four characters previously read into
+     * the putback m_buf (area of first four characters)
+     */
+    std::memmove(m_buf + (sizeof(int) - num_put_back),
+                 gptr() - num_put_back, num_put_back);
+
+    // read new characters
+    const int num = gzread(m_gz_file, m_buf + sizeof(int),
+                           kBufSize - sizeof(int));
+    if (num <= 0) {
+      // ERROR or EOF
+      return EOF;
+    }
+
+    // reset m_buf pointers
+    setg(m_buf + (sizeof(int) - num_put_back),   // beginning of putback area
+         m_buf + sizeof(int),                // read position
+         m_buf + sizeof(int) + num);           // end of buffer
+
+    // return next character
+    return traits_type::to_int_type(*gptr());
+  }
+
+  std::streamsize xsgetn(char* s,
+                         std::streamsize num) {
+    return gzread(m_gz_file,s,num);
+  }
+
+private:
+  gzFile m_gz_file;
+  static const unsigned int kBufSize = 1024;
+  char m_buf[kBufSize];
+};
+
+#endif  // MERT_GZFILEBUF_H_
diff --git a/mert/gzfilebuf.h b/mert/gzfilebuf.h
deleted file mode 100644
index b0f9637b3..000000000
--- a/mert/gzfilebuf.h
+++ /dev/null
@@ -1,87 +0,0 @@
-#ifndef MERT_GZFILEBUF_H_
-#define MERT_GZFILEBUF_H_
-
-#include <streambuf>
-#include <zlib.h>
-#include <cstring>
-
-class gzfilebuf : public std::streambuf
-{
-public:
-  explicit gzfilebuf(const char *filename) {
-    _gzf = gzopen(filename, "rb");
-    setg (_buff+sizeof(int),     // beginning of putback area
-          _buff+sizeof(int),     // read position
-          _buff+sizeof(int));    // end position
-  }
-
-  virtual ~gzfilebuf() {
-    gzclose(_gzf);
-  }
-
-protected:
-  virtual int_type overflow (int_type c) {
-    throw;
-  }
-
-  // write multiple characters
-  virtual
-  std::streamsize xsputn (const char* s,
-                          std::streamsize num) {
-    throw;
-  }
-
-  virtual std::streampos seekpos ( std::streampos sp, std::ios_base::openmode which = std::ios_base::in | std::ios_base::out ) {
-    throw;
-  }
-
-  // read one character
-  virtual int_type underflow () {
-    // is read position before end of _buff?
-    if (gptr() < egptr()) {
-      return traits_type::to_int_type(*gptr());
-    }
-
-    /* process size of putback area
-     * - use number of characters read
-     * - but at most four
-     */
-    unsigned int numPutback = gptr() - eback();
-    if (numPutback > sizeof(int)) {
-      numPutback = sizeof(int);
-    }
-
-    /* copy up to four characters previously read into
-     * the putback _buff (area of first four characters)
-     */
-    std::memmove (_buff+(sizeof(int)-numPutback), gptr()-numPutback,
-                  numPutback);
-
-    // read new characters
-    int num = gzread(_gzf, _buff+sizeof(int), _buffsize-sizeof(int));
-    if (num <= 0) {
-      // ERROR or EOF
-      return EOF;
-    }
-
-    // reset _buff pointers
-    setg (_buff+(sizeof(int)-numPutback),   // beginning of putback area
-          _buff+sizeof(int),                // read position
-          _buff+sizeof(int)+num);           // end of buffer
-
-    // return next character
-    return traits_type::to_int_type(*gptr());
-  }
-
-  std::streamsize xsgetn (char* s,
-                          std::streamsize num) {
-    return gzread(_gzf,s,num);
-  }
-
-private:
-  gzFile _gzf;
-  static const unsigned int _buffsize = 1024;
-  char _buff[_buffsize];
-};
-
-#endif  // MERT_GZFILEBUF_H_