Add Timestamp::totalNumberOfFrames() method, clarify some comments

svn-id: r47120

3 files changed, 22 insertions, 10 deletions

diff --git a/sound/audiostream.cpp b/sound/audiostream.cpp
index 79e8308115..6a3b1d792d 100644
--- a/sound/audiostream.cpp
+++ b/sound/audiostream.cpp
@@ -183,8 +183,7 @@ inline int32 calculatePlayTime(int rate, int samples) {
 }
 
 uint32 calculateSampleOffset(const Timestamp &where, int rate) {
-	const Timestamp whereRate = where.convertToFramerate(rate);
-	return whereRate.secs() * rate + whereRate.numberOfFrames();
+	return where.convertToFramerate(rate).totalNumberOfFrames();
 }
 
 /**
diff --git a/sound/audiostream.h b/sound/audiostream.h
index 528a6e25d8..15dce74661 100644
--- a/sound/audiostream.h
+++ b/sound/audiostream.h
@@ -152,9 +152,9 @@ private:
 };
 
 /**
- * A seekable audio stream. Subclasses of this class implement a
- * working seeking. The seeking itself is not required to be
- * working when the stream is being played by Mixer!
+ * A seekable audio stream. Subclasses of this class implement an
+ * interface for seeking. The seeking itself is not required to be
+ * working while the stream is being played by Mixer!
  */
 class SeekableAudioStream : public RewindableAudioStream {
 public:
diff --git a/sound/timestamp.h b/sound/timestamp.h
index cf149a65d0..699723e79b 100644
--- a/sound/timestamp.h
+++ b/sound/timestamp.h
@@ -129,21 +129,34 @@ public:
 	int msecsDiff(const Timestamp &ts) const;
 
 	/**
-	 * Determines the time in milliseconds described by this timestamp,
+	 * Return the time in milliseconds described by this timestamp,
 	 * rounded down.
 	 */
 	uint32 msecs() const;
 
 	/**
-	 * Determines the time in seconds described by this timestamp,
+	 * Return the time in seconds described by this timestamp,
 	 * rounded down.
 	 */
-	inline uint32 secs() const { return _secs; }
+	inline uint32 secs() const {
+		return _secs;
+	}
 
 	/**
-	 * Determines the frames described by this timestamp.
+	 * Return the time in frames described by this timestamp.
 	 */
-	inline int numberOfFrames() const { return _numberOfFrames / _framerateFactor; }
+	inline int totalNumberOfFrames() const {
+		return _numberOfFrames / _framerateFactor + _secs * (_framerate / _framerateFactor);
+	}
+
+	/**
+	 * A timestamp consists of a number of seconds, plus a number
+	 * of frames, the latter describing a fraction of a second.
+	 * This method returns the latter number.
+	 */
+	inline int numberOfFrames() const {
+		return _numberOfFrames / _framerateFactor;
+	}
 
 	/** Return the framerate used by this timestamp. */
 	inline int framerate() const { return _framerate / _framerateFactor; }