SCI: Added detection of some fan made script patches.

When such a script patch is found, a dialog pops up at the beginning
of the game, asking the user to remove it. The issues that these
script patches fix have already been fixed in ScummVM, thus these
patches aren't necessary, plus they can lead to crashes, freezes, buggy
behavior and/or unexpected errors, thus it is better if they aren't
used at all, if possible

svn-id: r53920

2 files changed, 73 insertions, 0 deletions

diff --git a/engines/sci/sci.cpp b/engines/sci/sci.cpp
index 98ce93d11f..839e033169 100644
--- a/engines/sci/sci.cpp
+++ b/engines/sci/sci.cpp
@@ -342,6 +342,13 @@ Common::Error SciEngine::run() {
 		}
 	}
 
+	if (gameHasFanMadePatch()) {
+		showScummVMDialog("Your game is patched with a fan made script patch. Such patches have "
+						  "been reported to cause issues, as they modify game scripts extensively. "
+						  "The issues that these patches fix do not occur in ScummVM, so you are "
+						  "advised to remove this patch from your game folder in order to avoid "
+						  "having unexpected errors and/or issues later on.");
+	}
 
 	runGame();
 
@@ -350,6 +357,70 @@ Common::Error SciEngine::run() {
 	return Common::kNoError;
 }
 
+bool SciEngine::gameHasFanMadePatch() {
+	struct FanMadePatchInfo {
+		SciGameId gameID;
+		uint16 targetScript;
+		uint16 targetSize;
+		uint16 patchedByteOffset;
+		byte patchedByte;
+	};
+
+	const FanMadePatchInfo patchInfo[] = {
+		// game        script    size  offset   byte
+		// ** NRS Patches **************************
+		{ GID_HOYLE3,     994,   2580,    656,  0x78 },
+		{ GID_KQ1,         85,   5156,    631,  0x02 },
+		{ GID_LAURABOW2,  994,   4382,      0,  0x00 },
+		{ GID_LONGBOW,    994,   4950,   1455,  0x78 },	// English
+		{ GID_LONGBOW,    994,   5020,   1469,  0x78 },	// German
+		{ GID_LSL1,       380,   7256,      0,  0x00 },
+		{ GID_LSL3,       380,   6148,    195,  0x35 },
+		{ GID_LSL5,       994,   4810,   1342,  0x78 },	// English
+		{ GID_LSL5,       994,   4942,   1392,  0x76 },	// German
+		{ GID_PQ1,        994,   4332,   1473,  0x78 },
+		{ GID_PQ2,        200,  10614,      0,  0x00 },
+		{ GID_PQ3,        994,   4686,   1291,  0x78 },	// English
+		{ GID_PQ3,        994,   4734,   1283,  0x78 },	// German
+		{ GID_QFG1VGA,    994,   4388,      0,  0x00 },
+		{ GID_QFG3,       994,   4714,      0,  0x00 },
+		// TODO: Disabled, as it fixes a whole lot of bugs which can't be tested till SCI2.1 support is finished
+		//{ GID_QFG4,       710,  11477,      0,  0x00 },
+		{ GID_SQ1,        994,   4740,      0,  0x00 },
+		{ GID_SQ5,        994,   4142,   1496,  0x78 },	// English/German/French
+		// TODO: Disabled, till we can test the Italian version
+		//{ GID_SQ5,        994,   4148,      0,  0x00 },	// Italian - patched file is the same size as the original
+		// TODO: The bugs in SQ6 can't be tested till SCI2.1 support is finished
+		//{ GID_SQ6,        380,  16308,  15042,  0x0C },	// English
+		//{ GID_SQ6,        380,  11652,      0,  0x00 },	// German - patched file is the same size as the original
+		// ** End marker ***************************
+		{ GID_FANMADE,      0,      0,      0,  0x00 }
+	};
+
+	int curEntry = 0;
+
+	while (true) {
+		if (patchInfo[curEntry].targetSize == 0)
+			break;
+
+		if (patchInfo[curEntry].gameID == getGameId()) {
+			Resource *targetScript = _resMan->findResource(ResourceId(kResourceTypeScript, patchInfo[curEntry].targetScript), 0);
+
+			if (targetScript && targetScript->size + 2 == patchInfo[curEntry].targetSize) {
+				byte foo = targetScript->data[patchInfo[curEntry].patchedByteOffset];
+				if (patchInfo[curEntry].patchedByteOffset == 0)
+					return true;
+				else if (targetScript->data[patchInfo[curEntry].patchedByteOffset - 2] == patchInfo[curEntry].patchedByte)
+					return true;
+			}
+		}
+
+		curEntry++;
+	}
+
+	return false;
+}
+
 static byte patchGameRestoreSave[] = {
 	0x39, 0x03,        // pushi 03
 	0x76,              // push0
diff --git a/engines/sci/sci.h b/engines/sci/sci.h
index 8ecdadb8ff..606cc008ee 100644
--- a/engines/sci/sci.h
+++ b/engines/sci/sci.h
@@ -348,6 +348,8 @@ private:
 
 	void initStackBaseWithSelector(Selector selector);
 
+	bool gameHasFanMadePatch();
+
 	const ADGameDescription *_gameDescription;
 	const SciGameId _gameId;
 	ResourceManager *_resMan; /**< The resource manager */