Merge pull request #434 from noborus/improved-export2

Export changed getting line

oviewer/document.go

@@ -326,8 +326,18 @@ func (m *Document) CurrentLN() int {
 // Export exports the document in the specified range.
 func (m *Document) Export(w io.Writer, start int, end int) {
 	end = min(end, m.BufEndNum()-1)
-	for n := start; n <= end; n++ {
-		fmt.Fprintln(w, m.GetLine(n))
+	startChunk, startCn := chunkLineNum(start)
+	endChunk, endCn := chunkLineNum(end)
+
+	scn := startCn
+	ecn := ChunkSize
+	for chunkNum := startChunk; chunkNum <= endChunk; chunkNum++ {
+		if chunkNum == endChunk {
+			ecn = endCn + 1
+		}
+		chunk := m.store.chunks[chunkNum]
+		m.store.export(w, chunk, scn, ecn)
+		scn = 0
 	}
 }
 

oviewer/store.go

@@ -359,3 +359,21 @@ func (s *store) appendFormFeed(chunk *chunk) {
 		s.appendLine(chunk, []byte(feed))
 	}
 }
+
+func (s *store) export(w io.Writer, chunk *chunk, start int, end int) error {
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+
+	if start < 0 {
+		start = 0
+	}
+	if end > len(chunk.lines) {
+		end = len(chunk.lines)
+	}
+	for i := start; i < end; i++ {
+		if _, err := w.Write(chunk.lines[i]); err != nil {
+			return err
+		}
+	}
+	return nil
+}