From 6d5eeec2cba5bc346b9416d4104daf0989ad184a Mon Sep 17 00:00:00 2001
From: "Adam D. Ruppe" <destructionator@gmail.com>
Date: Wed, 27 Jul 2022 13:45:08 -0400
Subject: [PATCH] allow extra compressed data

---
 png.d | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/png.d b/png.d
index 57e430a..be23235 100644
--- a/png.d
+++ b/png.d
@@ -1377,6 +1377,13 @@ struct LazyPngFile(LazyPngChunksProvider)
 						auto err = inflate(zs, Z_SYNC_FLUSH);
 						if (err != Z_STREAM_END && err != Z_OK) throw new Exception("PNG unpack error");
 						if (err == Z_STREAM_END) {
+							// this thing is malformed
+							if(zs.avail_in != 0) {
+								// libpng would warn here "libpng warning: IDAT: Extra compressed data"
+								// i used to just throw with the assertion on the next line
+								// but now just gonna discard the extra data to be a bit more permissive
+								zs.avail_in = 0;
+							}
 							assert(zs.avail_in == 0);
 							eoz = true;
 						}