Adding upstream version 2.1.2.

Signed-off-by: Daniel Baumann <daniel@debian.org>

fileutil.go

@@ -0,0 +1,49 @@
+package chart
+
+import (
+	"bufio"
+	"io"
+	"os"
+)
+
+// ReadLines reads a file and calls the handler for each line.
+func ReadLines(filePath string, handler func(string) error) error {
+	f, err := os.Open(filePath)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+
+	scanner := bufio.NewScanner(f)
+	for scanner.Scan() {
+		line := scanner.Text()
+		err = handler(line)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// ReadChunks reads a file in `chunkSize` pieces, dispatched to the handler.
+func ReadChunks(filePath string, chunkSize int, handler func([]byte) error) error {
+	f, err := os.Open(filePath)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+
+	chunk := make([]byte, chunkSize)
+	for {
+		readBytes, err := f.Read(chunk)
+		if err == io.EOF {
+			break
+		}
+		readData := chunk[:readBytes]
+		err = handler(readData)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}