1 files changed, 83 insertions, 0 deletions
diff --git a/textproto/fastimport.go b/textproto/fastimport.go
new file mode 100644
index 0000000..c845f7f
--- /dev/null
+++ b/textproto/fastimport.go
@@ -0,0 +1,83 @@
+package textproto
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"strconv"
+	"strings"
+)
+
+type FIReader struct {
+	r *bufio.Reader
+
+	line *string
+	err  error
+}
+
+func NewFIReader(r io.Reader) *FIReader {
+	return &FIReader{
+		r: bufio.NewReader(r),
+	}
+}
+
+func (fir *FIReader) ReadLine() (line string, err error) {
+	for len(line) <= 1 {
+		line, err = fir.r.ReadString('\n')
+		if err != nil {
+			return
+		}
+	}
+
+	if strings.HasPrefix(line, "data ") {
+		if line[5:7] == "<<" {
+			// Delimited format
+			delim := line[7 : len(line)-1]
+			suffix := "\n" + delim + "\n"
+
+			for !strings.HasSuffix(line, suffix) {
+				var _line string
+				_line, err = fir.r.ReadString('\n')
+				line += _line
+				if err != nil {
+					return
+				}
+			}
+		} else {
+			// Exact byte count format
+			var size int
+			size, err = strconv.Atoi(line[5 : len(line)-1])
+			if err != nil {
+				return
+			}
+			data := make([]byte, size)
+			_, err = io.ReadFull(fir.r, data)
+			line += string(data)
+		}
+	}
+	return
+}
+
+type FIWriter struct {
+	w io.Writer
+}
+
+func NewFIWriter(w io.Writer) *FIWriter {
+	return &FIWriter{
+		w: w,
+	}
+}
+
+func (fiw *FIWriter) WriteLine(a ...interface{}) error {
+	_, err := fmt.Fprintln(fiw.w, a...)
+	return err
+}
+
+func (fiw *FIWriter) WriteData(data string) error {
+	err := fiw.WriteLine("data", len(data))
+	if err != nil {
+		return err
+	}
+	_, err = io.WriteString(fiw.w, data)
+	return err
+}