SCI: Clean up validateExportFunc() and related functions

Also renamed some SCI3 related code to indicate when it's SCI3 specific

3 files changed, 28 insertions, 31 deletions

diff --git a/engines/sci/engine/script.cpp b/engines/sci/engine/script.cpp
index 897ceccad3..80aaedfece 100644
--- a/engines/sci/engine/script.cpp
+++ b/engines/sci/engine/script.cpp
@@ -385,7 +385,7 @@ void Script::setLockers(int lockers) {
 	_lockers = lockers;
 }
 
-uint16 Script::validateExportFunc(int pubfunct, bool relocate) {
+uint16 Script::validateExportFunc(int pubfunct, bool relocateSci3) {
 	bool exportsAreWide = (g_sci->_features->detectLofsType() == SCI_VERSION_1_MIDDLE);
 
 	if (_numExports <= pubfunct) {
@@ -398,15 +398,15 @@ uint16 Script::validateExportFunc(int pubfunct, bool relocate) {
 
 	uint16 offset;
 
-	if (getSciVersion() != SCI_VERSION_3 || !relocate) {
+	if (getSciVersion() != SCI_VERSION_3) {
 		offset = READ_SCI11ENDIAN_UINT16(_exportTable + pubfunct);
 	} else {
-		offset = relocateOffsetSci3(pubfunct * 2 + 22);
+		if (!relocateSci3)
+			offset = READ_SCI11ENDIAN_UINT16(_exportTable + pubfunct) + getCodeBlockOffsetSci3();
+		else
+			offset = relocateOffsetSci3(pubfunct * 2 + 22);
 	}
 
-	if (offset >= _bufSize)
-		error("Invalid export function pointer");
-
 	// Check if the offset found points to a second export table (e.g. script 912
 	// in Camelot and script 306 in KQ4). Such offsets are usually small (i.e. < 10),
 	// thus easily distinguished from actual code offsets.
@@ -419,11 +419,23 @@ uint16 Script::validateExportFunc(int pubfunct, bool relocate) {
 		if (secondExportTable) {
 			secondExportTable += 3;	// skip header plus 2 bytes (secondExportTable is a uint16 pointer)
 			offset = READ_SCI11ENDIAN_UINT16(secondExportTable + pubfunct);
-			if (offset >= _bufSize)
-				error("Invalid export function pointer");
 		}
 	}
 
+	if (!offset) {
+#ifdef ENABLE_SCI32
+		// WORKAROUNDS for invalid (empty) exports
+		if (g_sci->getGameId() == GID_TORIN && _nr == 64036) {
+		} else if (g_sci->getGameId() == GID_RAMA && _nr == 64908) {
+		} else
+#endif
+			error("Request for invalid exported function 0x%x of script %d", pubfunct, _nr);
+		return NULL;
+	}
+
+	if (offset >= _bufSize)
+		error("Invalid export function pointer");
+
 	return offset;
 }
 
@@ -551,7 +563,7 @@ void Script::initializeClasses(SegManager *segMan) {
 		if (getSciVersion() <= SCI_VERSION_1_LATE && !marker)
 			break;
 
-		if (getSciVersion() >= SCI_VERSION_1_1 && marker != 0x1234)
+		if (getSciVersion() >= SCI_VERSION_1_1 && marker != SCRIPT_OBJECT_MAGIC_NUMBER)
 			break;
 
 		if (getSciVersion() <= SCI_VERSION_1_LATE) {
diff --git a/engines/sci/engine/script.h b/engines/sci/engine/script.h
index 0c99f13235..9747f072c5 100644
--- a/engines/sci/engine/script.h
+++ b/engines/sci/engine/script.h
@@ -197,11 +197,11 @@ public:
 	 * Validate whether the specified public function is exported by
 	 * the script in the specified segment.
 	 * @param pubfunct		Index of the function to validate
-	 * @param relocate              Decide whether to relocate this public function or not
+	 * @param relocateSci3  Decide whether to relocate this SCI3 public function or not
 	 * @return				NULL if the public function is invalid, its
 	 * 						offset into the script's segment otherwise
 	 */
-	uint16 validateExportFunc(int pubfunct, bool relocate);
+	uint16 validateExportFunc(int pubfunct, bool relocateSci3);
 
 	/**
 	 * Marks the script as deleted.
@@ -249,7 +249,7 @@ public:
 	/**
 	 * Gets an offset to the beginning of the code block in a SCI3 script
 	 */
-	int getCodeBlockOffset() { return READ_SCI11ENDIAN_UINT32(_buf); }
+	int getCodeBlockOffsetSci3() { return READ_SCI11ENDIAN_UINT32(_buf); }
 
 private:
 	/**
diff --git a/engines/sci/engine/vm.cpp b/engines/sci/engine/vm.cpp
index 89f59eaa14..a42606a6a6 100644
--- a/engines/sci/engine/vm.cpp
+++ b/engines/sci/engine/vm.cpp
@@ -225,30 +225,15 @@ ExecStack *execute_method(EngineState *s, uint16 script, uint16 pubfunct, StackP
 		scr = s->_segMan->getScript(seg);
 	}
 
-	int temp = scr->validateExportFunc(pubfunct, false);
-
-	if (getSciVersion() == SCI_VERSION_3)
-		temp += scr->getCodeBlockOffset();
-
-	if (!temp) {
-#ifdef ENABLE_SCI32
-		if (g_sci->getGameId() == GID_TORIN && script == 64036) {
-			// Script 64036 in Torin's Passage is empty and contains an invalid
-			// (empty) export
-		} else if (g_sci->getGameId() == GID_RAMA && script == 64908) {
-			// Script 64908 in the demo of RAMA contains an invalid (empty)
-			// export
-		} else
-#endif
-			error("Request for invalid exported function 0x%x of script %d", pubfunct, script);
+	uint32 exportAddr = scr->validateExportFunc(pubfunct, false);
+	if (!exportAddr)
 		return NULL;
-	}
-
+	
 	// Check if a breakpoint is set on this method
 	g_sci->checkExportBreakpoint(script, pubfunct);
 
 	ExecStack xstack(calling_obj, calling_obj, sp, argc, argp,
-						seg, make_reg(seg, temp), -1, pubfunct, -1,
+						seg, make_reg(seg, exportAddr), -1, pubfunct, -1,
 						s->_executionStack.size() - 1, EXEC_STACK_TYPE_CALL);
 	s->_executionStack.push_back(xstack);
 	return &(s->_executionStack.back());