[sm130labels] Do not allow duplicate label names.

src/ScreenEdit.cpp

@@ -2669,13 +2669,13 @@ void ScreenEdit::HandleScreenMessage( const ScreenMessage SM )
 	else if ( SM == SM_BackFromLabelChange )
 	{
 		RString sLabel = ScreenTextEntry::s_sLastAnswer;
-		if ( sLabel.length() > 0 )
+		if ( !m_pSong->m_Timing.DoesLabelExist(sLabel) )
 		{
 			sLabel.Replace("=", "_");
 			sLabel.Replace(",", "_");
 			m_pSong->m_Timing.SetLabelAtBeat( GAMESTATE->m_fSongBeat, sLabel );
+			SetDirty( true );
 		}
-		SetDirty( true );
 	}
 	else if ( SM == SM_BackFromWarpChange )
 	{

src/TimingData.cpp

@@ -238,7 +238,7 @@ void TimingData::SetLabelAtRow( int iRow, const RString sLabel )
 	}
 	else
 	{
-		if( i > 0 && m_LabelSegments[i-1].m_sLabel == sLabel )
+		if( i > 0 && ( m_LabelSegments[i-1].m_sLabel == sLabel || sLabel == "" ) )
 			m_LabelSegments.erase( m_LabelSegments.begin()+i, m_LabelSegments.begin()+i+1 );
 		else
 			m_LabelSegments[i].m_sLabel = sLabel;
@@ -545,6 +545,16 @@ float TimingData::GetNextLabelSegmentBeatAtRow( int iRow ) const
 	return NoteRowToBeat(iRow);
 }
 
+bool TimingData::DoesLabelExist( RString sLabel ) const
+{
+	FOREACH_CONST( LabelSegment, m_LabelSegments, seg )
+	{
+		if( seg->m_sLabel == sLabel )
+			return true;
+	}
+	return false;
+}
+
 void TimingData::GetBeatAndBPSFromElapsedTime( float fElapsedTime, float &fBeatOut, float &fBPSOut, bool &bFreezeOut, bool &bDelayOut, int &iWarpBeginOut, float &fWarpLengthOut ) const
 {
 	fElapsedTime += PREFSMAN->m_fGlobalOffsetSeconds;

src/TimingData.h

@@ -1215,6 +1215,12 @@ public:
 	 */
 	float GetPreviousLabelSegmentBeatAtBeat( float fBeat ) const { return GetPreviousLabelSegmentBeatAtRow( BeatToNoteRow(fBeat) ); }
 
+	/**
+	 * @brief Determine if the requisite label already exists.
+	 * @param sLabel the label to check.
+	 * @return true if it exists, false otherwise. */
+	bool DoesLabelExist( RString sLabel ) const;
+	
 	/**
 	 * @brief Retrieve the next beat that contains a LabelSegment.
 	 * @param iRow the present row.