From 5e21b95ef1d85d45257a02c26dfe52ada60d3359 Mon Sep 17 00:00:00 2001
From: Klaus Post <klauspost@gmail.com>
Date: Mon, 9 Dec 2019 03:37:42 -0800
Subject: [PATCH 1/2] zstd: Add function to get decoder as io.ReadCloser

This is mostly for convenience.
---
 zstd/decoder.go | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/zstd/decoder.go b/zstd/decoder.go
index 1de94eef0c..b910bc2eef 100644
--- a/zstd/decoder.go
+++ b/zstd/decoder.go
@@ -388,6 +388,29 @@ func (d *Decoder) Close() {
 	d.current.err = ErrDecoderClosed
 }
 
+// IOReadCloser returns the decoder as an io.ReadCloser for convenience.
+// Any changes to the decoder will be reflected, so the returned ReadCloser
+// can be reused along with the decoder.
+func (d *Decoder) IOReadCloser() io.ReadCloser {
+	return closeWrapper{d: d}
+}
+
+// closeWrapper wraps a function call as a closer.
+type closeWrapper struct {
+	d *Decoder
+}
+
+// Read forwards read calls to the decoder.
+func (c closeWrapper) Read(p []byte) (n int, err error) {
+	return c.d.Read(p)
+}
+
+// Close closes the decoder.
+func (c closeWrapper) Close() error {
+	c.d.Close()
+	return nil
+}
+
 type decodeOutput struct {
 	d   *blockDec
 	b   []byte

From 26e3868e18611c28ccb75327cf5fdab3a4177e05 Mon Sep 17 00:00:00 2001
From: Klaus Post <klauspost@gmail.com>
Date: Mon, 9 Dec 2019 04:09:08 -0800
Subject: [PATCH 2/2] Add io.WriterTo support.

---
 zstd/decoder.go | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/zstd/decoder.go b/zstd/decoder.go
index b910bc2eef..35a3cda914 100644
--- a/zstd/decoder.go
+++ b/zstd/decoder.go
@@ -391,6 +391,7 @@ func (d *Decoder) Close() {
 // IOReadCloser returns the decoder as an io.ReadCloser for convenience.
 // Any changes to the decoder will be reflected, so the returned ReadCloser
 // can be reused along with the decoder.
+// io.WriterTo is also supported by the returned ReadCloser.
 func (d *Decoder) IOReadCloser() io.ReadCloser {
 	return closeWrapper{d: d}
 }
@@ -400,6 +401,11 @@ type closeWrapper struct {
 	d *Decoder
 }
 
+// WriteTo forwards WriteTo calls to the decoder.
+func (c closeWrapper) WriteTo(w io.Writer) (n int64, err error) {
+	return c.d.WriteTo(w)
+}
+
 // Read forwards read calls to the decoder.
 func (c closeWrapper) Read(p []byte) (n int, err error) {
 	return c.d.Read(p)