From eb034a2ea976ee68bb907805bf8fe19e6a3952bb Mon Sep 17 00:00:00 2001
From: greatroar <61184462+greatroar@users.noreply.github.com>
Date: Wed, 23 Nov 2022 20:09:24 +0100
Subject: [PATCH] zstd: Check ignoreChecksum option once

Decoder.nextBlock no longer calls the checksum finalizer if not
necessary.
---
 zstd/decoder.go | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/zstd/decoder.go b/zstd/decoder.go
index 74d645f7c3..832d7b7ae1 100644
--- a/zstd/decoder.go
+++ b/zstd/decoder.go
@@ -459,7 +459,11 @@ func (d *Decoder) nextBlock(blocking bool) (ok bool) {
 		println("got", len(d.current.b), "bytes, error:", d.current.err, "data crc:", tmp)
 	}
 
-	if !d.o.ignoreChecksum && len(next.b) > 0 {
+	if d.o.ignoreChecksum {
+		return true
+	}
+
+	if len(next.b) > 0 {
 		n, err := d.current.crc.Write(next.b)
 		if err == nil {
 			if n != len(next.b) {
@@ -471,7 +475,7 @@ func (d *Decoder) nextBlock(blocking bool) (ok bool) {
 		got := d.current.crc.Sum64()
 		var tmp [4]byte
 		binary.LittleEndian.PutUint32(tmp[:], uint32(got))
-		if !d.o.ignoreChecksum && !bytes.Equal(tmp[:], next.d.checkCRC) {
+		if !bytes.Equal(tmp[:], next.d.checkCRC) {
 			if debugDecoder {
 				println("CRC Check Failed:", tmp[:], " (got) !=", next.d.checkCRC, "(on stream)")
 			}