diff --git a/general/CMakeLists.txt b/general/CMakeLists.txt
index 2cbcde7..0011556 100644
--- a/general/CMakeLists.txt
+++ b/general/CMakeLists.txt
@@ -35,7 +35,7 @@ aux_source_directory(src/pattern PaternSrc)
 
 
 add_library(General OBJECT  ${DIRSRCS} ${PaternSrc} src/pattern/signleton.hpp src/pattern/Observer.hpp src/pattern/stratergy.hpp "src/pattern/adapter.hpp" src/encrypt/base64.cpp src/encrypt/base64.h src/encrypt/aes.cpp src/encrypt/aes.h src/encrypt/rsa.cpp
-        src/math/BigInt.hpp src/net/TcpClient.cpp src/net/TcpClient.h src/net/PackageReceiver.cpp src/net/PackageReceiver.h src/function/btree.cpp src/function/btree.h src/algorithm/sorter.hpp)
+        src/math/BigInt.hpp src/net/TcpClient.cpp src/net/TcpClient.h src/net/PackageReceiver.cpp src/net/PackageReceiver.h src/function/Timer.cpp src/function/btree.cpp src/function/btree.h src/algorithm/sorter.hpp)
 
 set(COPYITEM inc)
 file(GLOB INCLUDES ${PROJECT_SOURCE_DIR}/inc/*)
diff --git a/general/src/function/Timer.cpp b/general/src/function/Timer.cpp
new file mode 100644
index 0000000..84bd80c
--- /dev/null
+++ b/general/src/function/Timer.cpp
@@ -0,0 +1,132 @@
+//////////////////////////////////////////////////////////////////////////////
+// Timer.cpp
+// =========
+// High Resolution Timer.
+// This timer is able to measure the elapsed time with 1 micro-second accuracy
+// in both Windows, Linux and Unix system 
+//
+//  AUTHOR: Song Ho Ahn (song.ahn@gmail.com)
+// CREATED: 2003-01-13
+// UPDATED: 2017-03-30
+//
+// Copyright (c) 2003 Song Ho Ahn
+//////////////////////////////////////////////////////////////////////////////
+
+#include "Timer.h"
+#include <stdlib.h>
+
+///////////////////////////////////////////////////////////////////////////////
+// constructor
+///////////////////////////////////////////////////////////////////////////////
+Timer::Timer()
+{
+#if defined(WIN32) || defined(_WIN32)
+    QueryPerformanceFrequency(&frequency);
+    startCount.QuadPart = 0;
+    endCount.QuadPart = 0;
+#else
+    startCount.tv_sec = startCount.tv_usec = 0;
+    endCount.tv_sec = endCount.tv_usec = 0;
+#endif
+
+    stopped = 0;
+    startTimeInMicroSec = 0;
+    endTimeInMicroSec = 0;
+}
+
+
+
+///////////////////////////////////////////////////////////////////////////////
+// distructor
+///////////////////////////////////////////////////////////////////////////////
+Timer::~Timer()
+{
+}
+
+
+
+///////////////////////////////////////////////////////////////////////////////
+// start timer.
+// startCount will be set at this point.
+///////////////////////////////////////////////////////////////////////////////
+void Timer::start()
+{
+    stopped = 0; // reset stop flag
+#if defined(WIN32) || defined(_WIN32)
+    QueryPerformanceCounter(&startCount);
+#else
+    gettimeofday(&startCount, NULL);
+#endif
+}
+
+
+
+///////////////////////////////////////////////////////////////////////////////
+// stop the timer.
+// endCount will be set at this point.
+///////////////////////////////////////////////////////////////////////////////
+void Timer::stop()
+{
+    stopped = 1; // set timer stopped flag
+
+#if defined(WIN32) || defined(_WIN32)
+    QueryPerformanceCounter(&endCount);
+#else
+    gettimeofday(&endCount, NULL);
+#endif
+}
+
+
+
+///////////////////////////////////////////////////////////////////////////////
+// compute elapsed time in micro-second resolution.
+// other getElapsedTime will call this first, then convert to correspond resolution.
+///////////////////////////////////////////////////////////////////////////////
+double Timer::getElapsedTimeInMicroSec()
+{
+#if defined(WIN32) || defined(_WIN32)
+    if(!stopped)
+        QueryPerformanceCounter(&endCount);
+
+    startTimeInMicroSec = startCount.QuadPart * (1000000.0 / frequency.QuadPart);
+    endTimeInMicroSec = endCount.QuadPart * (1000000.0 / frequency.QuadPart);
+#else
+    if(!stopped)
+        gettimeofday(&endCount, NULL);
+
+    startTimeInMicroSec = (startCount.tv_sec * 1000000.0) + startCount.tv_usec;
+    endTimeInMicroSec = (endCount.tv_sec * 1000000.0) + endCount.tv_usec;
+#endif
+
+    return endTimeInMicroSec - startTimeInMicroSec;
+}
+
+
+
+///////////////////////////////////////////////////////////////////////////////
+// divide elapsedTimeInMicroSec by 1000
+///////////////////////////////////////////////////////////////////////////////
+double Timer::getElapsedTimeInMilliSec()
+{
+    return this->getElapsedTimeInMicroSec() * 0.001;
+}
+
+
+
+///////////////////////////////////////////////////////////////////////////////
+// divide elapsedTimeInMicroSec by 1000000
+///////////////////////////////////////////////////////////////////////////////
+double Timer::getElapsedTimeInSec()
+{
+    return this->getElapsedTimeInMicroSec() * 0.000001;
+}
+
+
+
+///////////////////////////////////////////////////////////////////////////////
+// same as getElapsedTimeInSec()
+///////////////////////////////////////////////////////////////////////////////
+double Timer::getElapsedTime()
+{
+    return this->getElapsedTimeInSec();
+}
diff --git a/general/src/function/Timer.h b/general/src/function/Timer.h
new file mode 100644
index 0000000..d24ab52
--- /dev/null
+++ b/general/src/function/Timer.h
@@ -0,0 +1,56 @@
+//////////////////////////////////////////////////////////////////////////////
+// Timer.h
+// =======
+// High Resolution Timer.
+// This timer is able to measure the elapsed time with 1 micro-second accuracy
+// in both Windows, Linux and Unix system 
+//
+//  AUTHOR: Song Ho Ahn (song.ahn@gmail.com)
+// CREATED: 2003-01-13
+// UPDATED: 2017-03-30
+//
+// Copyright (c) 2003 Song Ho Ahn
+//////////////////////////////////////////////////////////////////////////////
+
+#ifndef TIMER_H_DEF
+#define TIMER_H_DEF
+
+#if defined(WIN32) || defined(_WIN32)   // Windows system specific
+#include <windows.h>
+#else          // Unix based system specific
+#include <sys/time.h>
+#endif
+
+
+class Timer
+{
+public:
+    Timer();                                    // default constructor
+    ~Timer();                                   // default destructor
+
+    void   start();                             // start timer
+    void   stop();                              // stop the timer
+    double getElapsedTime();                    // get elapsed time in second
+    double getElapsedTimeInSec();               // get elapsed time in second (same as getElapsedTime)
+    double getElapsedTimeInMilliSec();          // get elapsed time in milli-second
+    double getElapsedTimeInMicroSec();          // get elapsed time in micro-second
+
+
+protected:
+
+
+private:
+    double startTimeInMicroSec;                 // starting time in micro-second
+    double endTimeInMicroSec;                   // ending time in micro-second
+    int    stopped;                             // stop flag 
+#if defined(WIN32) || defined(_WIN32)
+    LARGE_INTEGER frequency;                    // ticks per second
+    LARGE_INTEGER startCount;                   //
+    LARGE_INTEGER endCount;                     //
+#else
+    timeval startCount;                         //
+    timeval endCount;                           //
+#endif
+};
+
+#endif // TIMER_H_DEF