Added utility function to get elapsed duration i.e. how much so far has been read from the WAV file

source/SoundStretch/WavFile.cpp

@@ -651,6 +651,14 @@ uint WavInFile::getLengthMS() const
 }
 
 
+/// Returns how many milliseconds of audio have so far been read from the file
+uint WavInFile::getElapsedMS() const
+{
+    return (uint)(1000.0 * (double)dataRead / (double)header.format.byte_rate);
+}
+
+
+
 //////////////////////////////////////////////////////////////////////////////
 //
 // Class WavOutFile

source/SoundStretch/WavFile.h

@@ -116,8 +116,11 @@ private:
     /// File pointer.
     FILE *fptr;
 
+    /// Position within the audio stream
+    long position;
+
     /// Counter of how many bytes of sample data have been read from the file.
-    uint dataRead;
+    long dataRead;
 
     /// WAV header information
     WavHeader header;
@@ -175,6 +178,11 @@ public:
     /// Get the audio file length in milliseconds
     uint getLengthMS() const;
 
+    /// Returns how many milliseconds of audio have so far been read from the file
+    ///
+    /// \return elapsed duration in milliseconds
+    uint getElapsedMS() const;
+
     /// Reads audio samples from the WAV file. This routine works only for 8 bit samples.
     /// Reads given number of elements from the file or if end-of-file reached, as many 
     /// elements as are left in the file.