From 61ec98de02054749b4c471e341f0f4657aa818bc Mon Sep 17 00:00:00 2001
From: Teemu Suutari <tz@iki.fi>
Date: Fri, 22 Nov 2024 21:40:29 +0200
Subject: [PATCH] Detection fixing

---
 src/Decompressor.cpp    | 22 ++++++++++------------
 src/IceDecompressor.cpp |  2 +-
 2 files changed, 11 insertions(+), 13 deletions(-)

diff --git a/src/Decompressor.cpp b/src/Decompressor.cpp
index 9add444..e7fbbf6 100644
--- a/src/Decompressor.cpp
+++ b/src/Decompressor.cpp
@@ -51,7 +51,8 @@ static std::vector<std::pair<bool(*)(uint32_t,uint32_t),std::shared_ptr<Decompre
 	{TPWMDecompressor::detectHeader,TPWMDecompressor::create},
 	{VicXDecompressor::detectHeader,VicXDecompressor::create},
 	{XPKMain::detectHeader,XPKMain::create},
-	// Putting StoneCracker last since detection can be accidentally be detected instead of correct format
+	// Formats with missing id / uncertain detection
+	// old stonecracker is far from certain
 	{StoneCrackerDecompressor::detectHeader,StoneCrackerDecompressor::create}
 	};
 
@@ -63,7 +64,12 @@ std::shared_ptr<Decompressor> Decompressor::create(const Buffer &packedData,bool
 		uint32_t footer{(exactSizeKnown&&packedData.size()>=4)?packedData.readBE32(packedData.size()-4):0};
 		for (auto &it : decompressors)
 		{
-			if (it.first(hdr,footer)) return it.second(packedData,exactSizeKnown,verify);
+			try
+			{
+				if (it.first(hdr,footer)) return it.second(packedData,exactSizeKnown,verify);
+			} catch (const Error&) {
+				// try next on the list
+			}
 		}
 		throw InvalidFormatError();
 	} catch (const Buffer::Error&) {
@@ -74,16 +80,8 @@ std::shared_ptr<Decompressor> Decompressor::create(const Buffer &packedData,bool
 bool Decompressor::detect(const Buffer &packedData,bool exactSizeKnown) noexcept
 {
 	if (packedData.size()<2) return false;
-	try
-	{
-		uint32_t hdr{(packedData.size()>=4)?packedData.readBE32(0):(uint32_t(packedData.readBE16(0))<<16)};
-		uint32_t footer{(exactSizeKnown&&packedData.size()>=4)?packedData.readBE32(packedData.size()-4):0};
-		for (auto &it : decompressors)
-			if (it.first(hdr,footer)) return true;
-		return false;
-	} catch (const Buffer::Error&) {
-		return false;
-	}
+	// need to create the decompressor in order to work with bad detectors.
+	return bool(create(packedData,exactSizeKnown,true));
 }
 
 void Decompressor::decompress(Buffer &rawData,bool verify)
diff --git a/src/IceDecompressor.cpp b/src/IceDecompressor.cpp
index 51fc22f..6eb0172 100644
--- a/src/IceDecompressor.cpp
+++ b/src/IceDecompressor.cpp
@@ -151,7 +151,7 @@ void IceDecompressor::decompressInternal(Buffer &rawData,bool useBytes)
 	}
 
 	// picture mode
-	if (_ver && readBits(1U))
+	if (_ver && bitReader.available() && readBits(1U))
 	{
 		uint32_t pictureSize=32000U;
 		if (_ver==2)