HaikuDepot: Added Insert(TextSpan) to Paragraph

src/apps/haiku-depot/textview/Paragraph.cpp

@@ -79,3 +79,47 @@ Paragraph::Append(const TextSpan& span)
 	}
 	return fTextSpans.Add(span);
 }
+
+
+bool
+Paragraph::Insert(int32 offset, const TextSpan& newSpan)
+{
+	int32 index = 0;
+	while (index < fTextSpans.CountItems()) {
+		const TextSpan& span = fTextSpans.ItemAtFast(index);
+		if (offset - span.CharCount() < 0)
+			break;
+		offset -= span.CharCount();
+	}
+
+	if (fTextSpans.CountItems() == index)
+		return Append(newSpan);
+
+	// Try to merge with span at index if the TextStyles are equal
+	TextSpan span = fTextSpans.ItemAtFast(index);
+	if (span.Style() == newSpan.Style()) {
+		span.Insert(offset, newSpan.Text());
+		return fTextSpans.Replace(span, index);
+	}
+
+	if (offset == 0) {
+		if (index > 0) {
+			// Try to merge with TextSpan before if offset == 0 && index > 0
+			TextSpan span = fTextSpans.ItemAtFast(index - 1);
+			if (span.Style() == newSpan.Style()) {
+				span.Insert(span.CharCount(), newSpan.Text());
+				return fTextSpans.Replace(span, index - 1);
+			}
+		}
+		// Just insert the new span before the one at index
+		return fTextSpans.Add(newSpan, index);
+	}
+
+	// Split the span, 
+	TextSpan spanBefore = span.SubSpan(0, offset);
+	TextSpan spanAfter = span.SubSpan(offset, span.CharCount() - offset);
+
+	return fTextSpans.Replace(spanBefore, index)
+		&& fTextSpans.Add(newSpan, index + 1)
+		&& fTextSpans.Add(spanAfter, index + 2);
+}

src/apps/haiku-depot/textview/Paragraph.h

@@ -31,6 +31,7 @@ public:
 									{ return fTextSpans; }
 
 			bool				Append(const TextSpan& span);
+			bool				Insert(int32 offset, const TextSpan& span);
 
 private:
 			ParagraphStyle		fStyle;