1 files changed, 64 insertions, 0 deletions
diff --git a/format/sideband64k/chunk_writer.go b/format/sideband64k/chunk_writer.go
new file mode 100644
index 00000000..f95f75d8
--- /dev/null
+++ b/format/sideband64k/chunk_writer.go
@@ -0,0 +1,64 @@
+package sideband64k
+
+import "io"
+
+// ChunkWriter packetizes arbitrary stream bytes into side-band-64k data frames
+// for one fixed band.
+//
+// It never writes control packets automatically.
+type ChunkWriter struct {
+	enc  *Encoder
+	band Band
+}
+
+// NewChunkWriter creates a chunking adapter over enc for one band.
+func NewChunkWriter(enc *Encoder, band Band) *ChunkWriter {
+	return &ChunkWriter{enc: enc, band: band}
+}
+
+// Write splits p into sideband frames not larger than enc's maxData.
+func (cw *ChunkWriter) Write(p []byte) (int, error) {
+	total := 0
+	maxData := cw.enc.effectiveMaxData()
+
+	for len(p) > 0 {
+		n := min(len(p), maxData)
+
+		err := cw.enc.WriteBand(cw.band, p[:n])
+		if err != nil {
+			return total, err
+		}
+
+		total += n
+		p = p[n:]
+	}
+
+	return total, nil
+}
+
+// ReadFrom reads from r and writes sideband frames to the encoder.
+func (cw *ChunkWriter) ReadFrom(r io.Reader) (int64, error) {
+	buf := make([]byte, cw.enc.effectiveMaxData())
+
+	var total int64
+
+	for {
+		n, err := r.Read(buf)
+		if n > 0 {
+			werr := cw.enc.WriteBand(cw.band, buf[:n])
+			if werr != nil {
+				return total, werr
+			}
+
+			total += int64(n)
+		}
+
+		if err != nil {
+			if err == io.EOF {
+				return total, nil
+			}
+
+			return total, err
+		}
+	}
+}