diff --git a/CMakeLists.txt b/CMakeLists.txt
index 068bcee..66a2cd6 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -165,11 +165,14 @@ add_executable(pdf2htmlEX
     src/BackgroundRenderer/CairoBackgroundRenderer.cc 
     src/util/ArgParser.h
     src/util/ArgParser.cc
+    src/util/base64.h
+    src/util/base64.cc
     src/util/const.h
     src/util/const.cc
     src/util/ffw.h
     src/util/ffw.c
     src/util/namespace.h
+    src/util/string_formatter.h
     src/util/TmpFiles.h
     src/util/TmpFiles.cc
     src/util/unicode.h
diff --git a/src/HTMLRenderer/HTMLRenderer.h b/src/HTMLRenderer/HTMLRenderer.h
index 2922a8e..9ff3b11 100644
--- a/src/HTMLRenderer/HTMLRenderer.h
+++ b/src/HTMLRenderer/HTMLRenderer.h
@@ -27,6 +27,7 @@
 #include "Param.h"
 #include "Preprocessor.h"
 #include "util/util.h"
+#include "util/string_formatter.h"
 #include "util/TmpFiles.h"
 
 /*
diff --git a/src/HTMLRenderer/export.cc b/src/HTMLRenderer/export.cc
index b3fa713..5c79e43 100644
--- a/src/HTMLRenderer/export.cc
+++ b/src/HTMLRenderer/export.cc
@@ -12,6 +12,7 @@
 
 #include "HTMLRenderer.h"
 #include "util/namespace.h"
+#include "util/base64.h"
 
 namespace pdf2htmlEX {
 
diff --git a/src/HTMLRenderer/general.cc b/src/HTMLRenderer/general.cc
index a8253bc..ab83699 100644
--- a/src/HTMLRenderer/general.cc
+++ b/src/HTMLRenderer/general.cc
@@ -18,6 +18,7 @@
 #include "BackgroundRenderer/BackgroundRenderer.h"
 #include "util/namespace.h"
 #include "util/ffw.h"
+#include "util/base64.h"
 
 namespace pdf2htmlEX {
 
diff --git a/src/util/base64.cc b/src/util/base64.cc
new file mode 100644
index 0000000..51b4a7e
--- /dev/null
+++ b/src/util/base64.cc
@@ -0,0 +1,3 @@
+#include "base64.h"
+
+const char * base64stream::base64_encoding = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
diff --git a/src/util/base64.h b/src/util/base64.h
new file mode 100644
index 0000000..efebac8
--- /dev/null
+++ b/src/util/base64.h
@@ -0,0 +1,62 @@
+/*
+ * Base64 Encoding
+ *
+ * by WangLu
+ * 2012.11.29
+ */
+
+#ifndef BASE64_H__
+#define BASE64_H__
+
+#include <iostream>
+
+class base64stream
+{
+public:
+
+    base64stream(std::istream & in) : in(&in) { }
+    base64stream(std::istream && in) : in(&in) { }
+
+    std::ostream & dumpto(std::ostream & out)
+    {
+        unsigned char buf[3];
+        while(in->read((char*)buf, 3))
+        {
+            out << base64_encoding[(buf[0] & 0xfc)>>2]
+                << base64_encoding[((buf[0] & 0x03)<<4) | ((buf[1] & 0xf0)>>4)]
+                << base64_encoding[((buf[1] & 0x0f)<<2) | ((buf[2] & 0xc0)>>6)]
+                << base64_encoding[(buf[2] & 0x3f)];
+        } 
+        auto cnt = in->gcount();
+        if(cnt > 0)
+        {
+            for(int i = cnt; i < 3; ++i)
+                buf[i] = 0;
+
+            out << base64_encoding[(buf[0] & 0xfc)>>2]
+                << base64_encoding[((buf[0] & 0x03)<<4) | ((buf[1] & 0xf0)>>4)];
+
+            if(cnt > 1)
+            {
+                out << base64_encoding[(buf[1] & 0x0f)<<2];
+            }
+            else
+            {
+                out <<  '=';
+            }
+            out << '=';
+        }
+
+        return out;
+    }
+
+private:
+    std::istream * in;
+    static const char * base64_encoding;
+};
+
+static inline std::ostream & operator << (std::ostream & out, base64stream & bf) { return bf.dumpto(out); }
+static inline std::ostream & operator << (std::ostream & out, base64stream && bf) { return bf.dumpto(out); }
+
+
+#endif //BASE64_H__
diff --git a/src/util/string_formatter.h b/src/util/string_formatter.h
new file mode 100644
index 0000000..64da233
--- /dev/null
+++ b/src/util/string_formatter.h
@@ -0,0 +1,53 @@
+/*
+ * Buffer reusing string formatter
+ *
+ * by WangLu
+ * 2012.11.29
+ */
+
+#ifndef STRING_FORMATTER_H__
+#define STRING_FORMATTER_H__
+
+class string_formatter
+{
+public:
+    class guarded_pointer
+    {
+    public:
+        guarded_pointer(string_formatter * sf) : sf(sf) { ++(sf->buf_cnt); }
+        ~guarded_pointer(void) { --(sf->buf_cnt); }
+        operator char* () { return &(sf->buf.front()); }
+    private:
+        string_formatter * sf;
+    };
+
+    string_formatter() : buf_cnt(0) { buf.reserve(L_tmpnam); }
+    /*
+     * Important:
+     * there is only one buffer, so new strings will replace old ones
+     */
+    guarded_pointer operator () (const char * format, ...) {
+        assert((buf_cnt == 0) && "string_formatter: buffer is reused!");
+
+        va_list vlist;
+        va_start(vlist, format);
+        int l = vsnprintf(&buf.front(), buf.capacity(), format, vlist);
+        va_end(vlist);
+        if(l >= (int)buf.capacity()) 
+        {
+            buf.reserve(std::max<long>((long)(l+1), (long)buf.capacity() * 2));
+            va_start(vlist, format);
+            l = vsnprintf(&buf.front(), buf.capacity(), format, vlist);
+            va_end(vlist);
+        }
+        assert(l >= 0); // we should fail when vsnprintf fail
+        assert(l < (int)buf.capacity());
+        return guarded_pointer(this);
+    }
+private:
+    friend class guarded_pointer;
+    std::vector<char> buf;
+    int buf_cnt;
+};
+
+#endif //STRING_FORMATTER_H__
diff --git a/src/util/util.cc b/src/util/util.cc
index 606b33d..feb09ea 100644
--- a/src/util/util.cc
+++ b/src/util/util.cc
@@ -54,9 +54,6 @@ void _tm_multiply(double * tm_left, const double * tm_right)
     tm_left[5] += old[1] * tm_right[4] + old[3] * tm_right[5];
 }
 
-
-const char * base64stream::base64_encoding = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
-
 void create_directories(string path)
 {
     if(path.empty()) return;
diff --git a/src/util/util.h b/src/util/util.h
index d10ef2e..e9011a9 100644
--- a/src/util/util.h
+++ b/src/util/util.h
@@ -92,96 +92,6 @@ public:
     }
 };
 
-class base64stream
-{
-public:
-
-    base64stream(std::istream & in) : in(&in) { }
-    base64stream(std::istream && in) : in(&in) { }
-
-    std::ostream & dumpto(std::ostream & out)
-    {
-        unsigned char buf[3];
-        while(in->read((char*)buf, 3))
-        {
-            out << base64_encoding[(buf[0] & 0xfc)>>2]
-                << base64_encoding[((buf[0] & 0x03)<<4) | ((buf[1] & 0xf0)>>4)]
-                << base64_encoding[((buf[1] & 0x0f)<<2) | ((buf[2] & 0xc0)>>6)]
-                << base64_encoding[(buf[2] & 0x3f)];
-        } 
-        auto cnt = in->gcount();
-        if(cnt > 0)
-        {
-            for(int i = cnt; i < 3; ++i)
-                buf[i] = 0;
-
-            out << base64_encoding[(buf[0] & 0xfc)>>2]
-                << base64_encoding[((buf[0] & 0x03)<<4) | ((buf[1] & 0xf0)>>4)];
-
-            if(cnt > 1)
-            {
-                out << base64_encoding[(buf[1] & 0x0f)<<2];
-            }
-            else
-            {
-                out <<  '=';
-            }
-            out << '=';
-        }
-
-        return out;
-    }
-
-private:
-    std::istream * in;
-    static const char * base64_encoding;
-};
-
-static inline std::ostream & operator << (std::ostream & out, base64stream & bf) { return bf.dumpto(out); }
-static inline std::ostream & operator << (std::ostream & out, base64stream && bf) { return bf.dumpto(out); }
-
-class string_formatter
-{
-public:
-    class guarded_pointer
-    {
-    public:
-        guarded_pointer(string_formatter * sf) : sf(sf) { ++(sf->buf_cnt); }
-        ~guarded_pointer(void) { --(sf->buf_cnt); }
-        operator char* () { return &(sf->buf.front()); }
-    private:
-        string_formatter * sf;
-    };
-
-    string_formatter() : buf_cnt(0) { buf.reserve(L_tmpnam); }
-    /*
-     * Important:
-     * there is only one buffer, so new strings will replace old ones
-     */
-    guarded_pointer operator () (const char * format, ...) {
-        assert((buf_cnt == 0) && "string_formatter: buffer is reused!");
-
-        va_list vlist;
-        va_start(vlist, format);
-        int l = vsnprintf(&buf.front(), buf.capacity(), format, vlist);
-        va_end(vlist);
-        if(l >= (int)buf.capacity()) 
-        {
-            buf.reserve(std::max<long>((long)(l+1), (long)buf.capacity() * 2));
-            va_start(vlist, format);
-            l = vsnprintf(&buf.front(), buf.capacity(), format, vlist);
-            va_end(vlist);
-        }
-        assert(l >= 0); // we should fail when vsnprintf fail
-        assert(l < (int)buf.capacity());
-        return guarded_pointer(this);
-    }
-private:
-    friend class guarded_pointer;
-    std::vector<char> buf;
-    int buf_cnt;
-};
-
 void create_directories(std::string path);
 
 bool is_truetype_suffix(const std::string & suffix);