From 9336278b454720da4f6288ed475fd56d09b44a2b Mon Sep 17 00:00:00 2001
From: Simon Delamarre <simon.delamarre14@gmail.com>
Date: Sat, 28 Feb 2026 11:08:01 +0100
Subject: [PATCH] IMAGE: Handle ANI files wrongly including header size in the
 chunk size field

Found for example in Adi4's waiting cursor "WAIT.ANI"
---
 image/ani.cpp | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/image/ani.cpp b/image/ani.cpp
index f662292205b..218a30b55e6 100644
--- a/image/ani.cpp
+++ b/image/ani.cpp
@@ -125,8 +125,15 @@ bool AniDecoder::parseRIFFChunks(Common::SeekableReadStream &stream, const RIFFC
 
 		int64 chunkAvailable = stream.size() - stream.pos();
 		if (chunkAvailable < actualChunkSize) {
-			warning("AniDecoder::parseRIFFChunk: RIFF chunk is too large");
-			return false;
+			if (chunkAvailable == chunkSize - 8) {
+				// Some ANI files wrongly include the 8-byte chunk header size in the chunk size field, tolerate that
+				warning("AniDecoder::parseRIFFChunks: Chunk size seems to include header size, clamping");
+				chunkSize = static_cast<uint32>(chunkAvailable);
+				actualChunkSize = chunkSize;
+			} else {
+				warning("AniDecoder::parseRIFFChunk: RIFF chunk is too large");
+				return false;
+			}
 		}
 
 		RIFFChunkDef chunkDef;