fixed a bug in wxStopWatch::Pause() (wouldn't pause if called immediately after Start()) and changed Pause()/Resume() calls to nest

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@15051 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

docs/changes.txt

@@ -26,6 +26,8 @@ wxBase:
   documentation for details and revise your code accordingly: this change was
   unfortunately needed as the old class didn't behave correctly in all cases
 
+- small change to wxStopWatch::Pause() semantics, please see the documentation
+
 All (GUI):
 
 - the event type constants are not constants any more but are dynamically

docs/latex/wx/stopwtch.tex

@@ -1,6 +1,19 @@
 \section{\class{wxStopWatch}}\label{wxstopwatch}
 
-The wxStopWatch class allow you to measure time intervals.
+The wxStopWatch class allow you to measure time intervals. For example, you may
+use it to measure the time elapsed by some function:
+
+\begin{verbatim}
+    wxStopWatch sw;
+    CallLongRunningFunction();
+    wxLogMessage("The long running function took %ldms to execute",
+                 sw.Time());
+    sw.Pause();
+    ... stopwatch is stopped now ...
+    sw.Resume();
+    CallLongRunningFunction();
+    wxLogMessage("And calling it twice took $ldms in all", sw.Time());
+\end{verbatim}
 
 \wxheading{Include files}
 
@@ -25,17 +38,22 @@ Constructor. This starts the stop watch.
 Pauses the stop watch. Call \helpref{wxStopWatch::Resume}{wxstopwatchresume} to resume 
 time measuring again.
 
-\membersection{wxStopWatch::Start}
-
-\func{void}{Start}{\param{long}{ milliseconds = 0}}
-
-(Re)starts the stop watch with a given initial value.
+If this method is called several times, {\tt Resume()} must be called the same
+number of times to really resume the stop watch. You may, however, call 
+\helpref{Start}{wxstopwatchstart} to resume it unconditionally.
 
 \membersection{wxStopWatch::Resume}\label{wxstopwatchresume}
 
 \func{void}{Resume}{\void}
 
-Resumes the stop watch after having been paused with \helpref{wxStopWatch::Pause}{wxstopwatchpause}.
+Resumes the stop watch which had been paused with 
+\helpref{wxStopWatch::Pause}{wxstopwatchpause}.
+
+\membersection{wxStopWatch::Start}\label{wxstopwatchstart}
+
+\func{void}{Start}{\param{long}{ milliseconds = 0}}
+
+(Re)starts the stop watch with a given initial value.
 
 \membersection{wxStopWatch::Time}
 

include/wx/timer.h

@@ -191,12 +191,18 @@ class WXDLLEXPORT wxStopWatch
 {
 public:
     // ctor starts the stop watch
-    wxStopWatch()        { Start(); }
-    void Start(long t = 0);
-    void Pause()  { m_pause = GetElapsedTime(); }
-    void Resume() { Start(m_pause); }
+    wxStopWatch() { m_pauseCount = 0; Start(); }
 
-    // get elapsed time since the last Start() or Pause() in milliseconds
+    // start the stop watch at the moment t0
+    void Start(long t0 = 0);
+
+    // pause the stop watch
+    void Pause() { if ( !m_pauseCount++) m_pause = GetElapsedTime(); }
+
+    // resume it
+    void Resume() { if ( !--m_pauseCount ) Start(m_pause); }
+
+    // get elapsed time since the last Start() in milliseconds
     long Time() const;
 
 protected:
@@ -204,8 +210,14 @@ protected:
     long GetElapsedTime() const;
 
 private:
-    wxLongLong m_t0;      // the time of the last Start()
-    long m_pause;         // the time of the last Pause() or 0
+    // the time of the last Start()
+    wxLongLong m_t0;
+
+    // the time of the last Pause() (only valid if m_pauseCount > 0)
+    long m_pause;
+
+    // if > 0, the stop watch is paused, otherwise it is running
+    int m_pauseCount;
 };
 
 #endif // wxUSE_STOPWATCH

samples/console/console.cpp

@@ -91,7 +91,7 @@
     #undef TEST_ALL
     static const bool TEST_ALL = TRUE;
 #else
-    #define TEST_FILENAME
+    #define TEST_TIMER
 
     static const bool TEST_ALL = FALSE;
 #endif
@@ -3032,18 +3032,28 @@ static void TestStopWatch()
     puts("*** Testing wxStopWatch ***\n");
 
     wxStopWatch sw;
-    printf("Sleeping 3 seconds...");
+    sw.Pause();
+    printf("Initially paused, after 2 seconds time is...");
+    fflush(stdout);
+    wxSleep(2);
+    printf("\t%ldms\n", sw.Time());
+
+    printf("Resuming stopwatch and sleeping 3 seconds...");
+    fflush(stdout);
+    sw.Resume();
     wxSleep(3);
     printf("\telapsed time: %ldms\n", sw.Time());
 
     sw.Pause();
-    printf("Sleeping 2 more seconds...");
+    printf("Pausing agan and sleeping 2 more seconds...");
+    fflush(stdout);
     wxSleep(2);
     printf("\telapsed time: %ldms\n", sw.Time());
 
     sw.Resume();
-    printf("And 3 more seconds...");
-    wxSleep(3);
+    printf("Finally resuming and sleeping 2 more seconds...");
+    fflush(stdout);
+    wxSleep(2);
     printf("\telapsed time: %ldms\n", sw.Time());
 
     wxStopWatch sw2;
@@ -3061,6 +3071,7 @@ static void TestStopWatch()
         }
 
         putchar('.');
+        fflush(stdout);
     }
 
     puts(", ok.");

src/common/timercmn.cpp

@@ -166,7 +166,7 @@ long wxStopWatch::GetElapsedTime() const
 
 long wxStopWatch::Time() const
 {
-    return (m_pause ? m_pause : GetElapsedTime());
+    return m_pauseCount ? m_pause : GetElapsedTime();
 }
 
 #endif // wxUSE_LONGLONG