Use MathExtras round() in timeToSampleFrame

https://bugs.webkit.org/show_bug.cgi?id=79281

Patch by Raymond Toy <rtoy@google.com> on 2012-02-23
Reviewed by Chris Rogers.

No new tests. Existing tests cover this change.

* platform/audio/AudioUtilities.cpp:
(WebCore::AudioUtilities::timeToSampleFrame): Use round().

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@108726 268f45cc-cd09-0410-ab3c-d52691b4dbfc

diff --git a/Source/WebCore/ChangeLog b/Source/WebCore/ChangeLog
index 6fafc48..a927f62 100644 (file)
--- a/Source/WebCore/ChangeLog
+++ b/Source/WebCore/ChangeLog
@@ -1,3 +1,15 @@
+2012-02-23  Raymond Toy  <rtoy@google.com>
+
+        Use MathExtras round() in timeToSampleFrame
+        https://bugs.webkit.org/show_bug.cgi?id=79281
+
+        Reviewed by Chris Rogers.
+
+        No new tests. Existing tests cover this change.
+
+        * platform/audio/AudioUtilities.cpp:
+        (WebCore::AudioUtilities::timeToSampleFrame): Use round(). 
+
 2012-02-23  Greg Billock  <gbillock@google.com>
 
         Don't clear IntentRequest callback pointers on stop()

diff --git a/Source/WebCore/platform/audio/AudioUtilities.cpp b/Source/WebCore/platform/audio/AudioUtilities.cpp
index ff19cee..7ec833c 100644 (file)
--- a/Source/WebCore/platform/audio/AudioUtilities.cpp
+++ b/Source/WebCore/platform/audio/AudioUtilities.cpp
@@ -56,38 +56,10 @@ float discreteTimeConstantForSampleRate(float timeConstant, float sampleRate)
     return 1 - powf(1 / 2.718282f, 1 / (sampleRate * timeConstant));
 }
 
-#if OS(WINDOWS) && COMPILER(MSVC) && !_M_IX86_FP
-// When compiling with MSVC with x87 FPU instructions using 80-bit
-// floats, we want very precise control over the arithmetic so that
-// rounding is done according to the IEEE 754 specification for
-// single- and double-precision floats. We want each operation to be
-// done with specified arithmetic precision and rounding consistent
-// with gcc, not extended to 80 bits automatically.
-//
-// These pragmas are equivalent to /fp:strict flag, but we only need
-// it for the function here.  (Using fp:strict everywhere can have
-// severe impact on floating point performance.)
-#pragma float_control(push)
-#pragma float_control(precise, on)
-#pragma fenv_access(on)
-#pragma float_control(except, on)
-#endif
-
 size_t timeToSampleFrame(double time, double sampleRate)
 {
-    // DO NOT CONSOLIDATE THESE ASSIGNMENTS INTO ONE! When compiling
-    // with Visual Studio, these assignments force the rounding of
-    // each operation according to IEEE 754, instead of leaving
-    // intermediate results in 80-bit precision which is not
-    // consistent with IEEE 754 double-precision rounding.
-    double r = time * sampleRate;
-    r += 0.5;
-    return static_cast<size_t>(r);
+    return static_cast<size_t>(round(time * sampleRate));
 }
-#if OS(WINDOWS) && COMPILER(MSVC) && !_M_IX86_FP
-// Restore normal floating-point semantics.
-#pragma float_control(pop)
-#endif
 } // AudioUtilites
 
 } // WebCore