patch to use mach absolute time on mac OS X since apple advises against gettimeofday...

diff --git a/src/os/unix/pa_unix_util.c b/src/os/unix/pa_unix_util.c
index 5b41c68704419e2e592ee16f796dc04edf844d8a..a0fcfcab7ffbe7adca7a749d7784c78ed8b7f70e 100644 (file)
--- a/src/os/unix/pa_unix_util.c
+++ b/src/os/unix/pa_unix_util.c
@@ -51,6 +51,13 @@
 #include <math.h>
 #include <errno.h>
 
+#if defined(__APPLE__) && !defined(HAVE_MACH_ABSOLUTE_TIME)
+#define HAVE_MACH_ABSOLUTE_TIME
+#endif
+#ifdef HAVE_MACH_ABSOLUTE_TIME
+#include <mach/mach_time.h>
+#endif
+
 #include "pa_util.h"
 #include "pa_unix_util.h"
 #include "pa_debugprint.h"
@@ -118,27 +125,47 @@ void Pa_Sleep( long msec )
 #endif
 }
 
-/*            *** NOT USED YET: ***
-static int usePerformanceCounter_;
-static double microsecondsPerTick_;
+#ifdef HAVE_MACH_ABSOLUTE_TIME
+/*
+    Discussion on the CoreAudio mailing list suggests that calling
+    gettimeofday (or anything else in the BSD layer) is not real-time
+    safe, so we use mach_absolute_time on OSX. This implementation is 
+    based on these two links:
+
+    Technical Q&A QA1398 - Mach Absolute Time Units
+    http://developer.apple.com/mac/library/qa/qa2004/qa1398.html
+
+    Tutorial: Performance and Time.
+    http://www.macresearch.org/tutorial_performance_and_time
 */
 
+/* Scaler to convert the result of mach_absolute_time to seconds */
+static double machSecondsConversionScaler_ = 0.0; 
+#endif
+
 void PaUtil_InitializeClock( void )
 {
-    /* TODO */
+#ifdef HAVE_MACH_ABSOLUTE_TIME
+    mach_timebase_info_data_t info;
+    kern_return_t err = mach_timebase_info( &info );
+    if( err == 0  )
+        machSecondsConversionScaler_ = 1e-9 * (double) info.numer / (double) info.denom;
+#endif
 }
 
 
 PaTime PaUtil_GetTime( void )
 {
-#ifdef HAVE_CLOCK_GETTIME
+#ifdef HAVE_MACH_ABSOLUTE_TIME
+    return mach_absolute_time() * machSecondsConversionScaler_;
+#elif defined(HAVE_CLOCK_GETTIME)
     struct timespec tp;
     clock_gettime(CLOCK_REALTIME, &tp);
-    return (PaTime)(tp.tv_sec + tp.tv_nsec / 1.e9);
+    return (PaTime)(tp.tv_sec + tp.tv_nsec * 1e-9);
 #else
     struct timeval tv;
     gettimeofday( &tv, NULL );
-    return (PaTime) tv.tv_usec / 1000000. + tv.tv_sec;
+    return (PaTime) tv.tv_usec * 1e-6 + tv.tv_sec;
 #endif
 }
 
@@ -190,7 +217,7 @@ PaError PaUtil_CancelThreading( PaUtilThreading *threading, int wait, PaError *e
 /* paUnixMainThread 
  * We have to be a bit careful with defining this global variable,
  * as explained below. */
-#ifdef __apple__
+#ifdef __APPLE__
 /* apple/gcc has a "problem" with global vars and dynamic libs.
    Initializing it seems to fix the problem.
    Described a bit in this thread: