Implemented a call stack

svn-id: r41754

8 files changed, 86 insertions, 68 deletions

diff --git a/engines/gob/draw.cpp b/engines/gob/draw.cpp
index 5c0cb47352..83266beb3a 100644
--- a/engines/gob/draw.cpp
+++ b/engines/gob/draw.cpp
@@ -391,9 +391,8 @@ void Draw::printTextCentered(int16 id, int16 left, int16 top, int16 right,
 	adjustCoords(1, &right, &bottom);
 
 	if (READ_LE_UINT16(_vm->_game->_script->getData() + 0x7E) != 0) {
-		uint32 startPos = _vm->_game->_script->pos();
+		_vm->_game->_script->call(READ_LE_UINT16(_vm->_game->_script->getData() + 0x7E));
 
-		_vm->_game->_script->seek(READ_LE_UINT16(_vm->_game->_script->getData() + 0x7E));
 		WRITE_VAR(17, (uint32) id);
 		WRITE_VAR(18, (uint32) left);
 		WRITE_VAR(19, (uint32) top);
@@ -401,7 +400,7 @@ void Draw::printTextCentered(int16 id, int16 left, int16 top, int16 right,
 		WRITE_VAR(21, (uint32) (bottom - top + 1));
 		_vm->_inter->funcBlock(0);
 
-		_vm->_game->_script->seek(startPos);
+		_vm->_game->_script->pop();
 	}
 
 	if (str[0] == '\0')
diff --git a/engines/gob/game.cpp b/engines/gob/game.cpp
index 8251219ed1..41cd6145a8 100644
--- a/engines/gob/game.cpp
+++ b/engines/gob/game.cpp
@@ -732,9 +732,7 @@ void Game::setCollisions(byte arg_0) {
 		if (((collArea->id & 0xC000) != 0x8000) || (collArea->funcSub == 0))
 			continue;
 
-		uint32 startPos = _script->pos();
-
-		_script->seek(collArea->funcSub);
+		_script->call(collArea->funcSub);
 
 		left = _script->readValExpr();
 		top = _script->readValExpr();
@@ -759,16 +757,14 @@ void Game::setCollisions(byte arg_0) {
 		collArea->right = left + width - 1;
 		collArea->bottom = top + height - 1;
 
-		_script->seek(startPos);
+		_script->pop();
 	}
 }
 
 void Game::collSub(uint16 offset) {
 	int16 collStackSize;
 
-	uint32 startPos = _script->pos();
-
-	_script->seek(offset);
+	_script->call(offset);
 
 	_shouldPushColls = 1;
 	collStackSize = _collStackSize;
@@ -780,7 +776,8 @@ void Game::collSub(uint16 offset) {
 
 	_shouldPushColls = 0;
 
-	_script->seek(startPos);
+	_script->pop();
+
 	setCollisions();
 }
 
diff --git a/engines/gob/game_v1.cpp b/engines/gob/game_v1.cpp
index c4fbe49bcc..b456e5aaeb 100644
--- a/engines/gob/game_v1.cpp
+++ b/engines/gob/game_v1.cpp
@@ -55,7 +55,7 @@ void Game_v1::playTot(int16 skipPlay) {
 	int16 *oldBreakFrom = _vm->_inter->_breakFromLevel;
 	int16 *oldCaptureCounter = _vm->_scenery->_pCaptureCounter;
 
-	uint32 startPos = _script->pos();
+	_script->push();
 
 	_vm->_inter->_nestLevel = &nestLevel;
 	_vm->_inter->_breakFromLevel = &breakFrom;
@@ -242,7 +242,7 @@ void Game_v1::playTot(int16 skipPlay) {
 	_vm->_inter->_breakFromLevel = oldBreakFrom;
 	_vm->_scenery->_pCaptureCounter = oldCaptureCounter;
 
-	_script->seek(startPos);
+	_script->pop();
 }
 
 void Game_v1::clearCollisions() {
@@ -358,13 +358,9 @@ int16 Game_v1::checkCollisions(byte handleMouse, int16 deltaTime,
 		_lastCollKey = checkMousePoint(1, &_lastCollId, &_lastCollAreaIndex);
 
 		if ((_lastCollKey != 0) && ((_lastCollId & 0x8000) != 0)) {
-			uint32 startPos = _script->pos();
-
-			_script->seek(_collisionAreas[_lastCollAreaIndex].funcEnter);
-
+			_script->call(_collisionAreas[_lastCollAreaIndex].funcEnter);
 			_vm->_inter->funcBlock(0);
-
-			_script->seek(startPos);
+			_script->pop();
 		}
 	}
 
@@ -426,13 +422,9 @@ int16 Game_v1::checkCollisions(byte handleMouse, int16 deltaTime,
 			if ((_lastCollKey != 0) &&
 			    (_collisionAreas[_lastCollAreaIndex].funcLeave != 0)) {
 
-				uint32 startPos = _script->pos();
-
-				_script->seek(_collisionAreas[_lastCollAreaIndex].funcLeave);
-
+				_script->call(_collisionAreas[_lastCollAreaIndex].funcLeave);
 				_vm->_inter->funcBlock(0);
-
-				_script->seek(startPos);
+				_script->pop();
 			}
 
 			_lastCollKey = 0;
@@ -467,13 +459,11 @@ int16 Game_v1::checkCollisions(byte handleMouse, int16 deltaTime,
 
 					if ((_lastCollKey != 0) &&
 						(_collisionAreas[_lastCollAreaIndex].funcLeave != 0)) {
-						uint32 startPos = _script->pos();
-
-						_script->seek(_collisionAreas[_lastCollAreaIndex].funcLeave);
 
+						_script->call(_collisionAreas[_lastCollAreaIndex].funcLeave);
 						_vm->_inter->funcBlock(0);
+						_script->pop();
 
-						_script->seek(startPos);
 					}
 					_lastCollKey = 0;
 					return key;
@@ -481,26 +471,22 @@ int16 Game_v1::checkCollisions(byte handleMouse, int16 deltaTime,
 
 				if ((_lastCollKey != 0) &&
 				    (_collisionAreas[_lastCollAreaIndex].funcLeave != 0)) {
-					uint32 startPos = _script->pos();
-
-					_script->seek(_collisionAreas[_lastCollAreaIndex].funcLeave);
 
+					_script->call(_collisionAreas[_lastCollAreaIndex].funcLeave);
 					_vm->_inter->funcBlock(0);
+					_script->pop();
 
-					_script->seek(startPos);
 				}
 
 				_lastCollKey =
 					checkMousePoint(1, &_lastCollId, &_lastCollAreaIndex);
 
 				if ((_lastCollKey != 0) && ((_lastCollId & 0x8000) != 0)) {
-					uint32 startPos = _script->pos();
-
-					_script->seek(_collisionAreas[_lastCollAreaIndex].funcEnter);
 
+					_script->call(_collisionAreas[_lastCollAreaIndex].funcEnter);
 					_vm->_inter->funcBlock(0);
+					_script->pop();
 
-					_script->seek(startPos);
 				}
 			} else {
 
@@ -514,24 +500,20 @@ int16 Game_v1::checkCollisions(byte handleMouse, int16 deltaTime,
 
 					if (key != _lastCollKey) {
 						if ((_lastCollKey != 0) && ((oldId & 0x8000) != 0)) {
-							uint32 startPos = _script->pos();
-
-							_script->seek(_collisionAreas[oldIndex].funcLeave);
 
+							_script->call(_collisionAreas[oldIndex].funcLeave);
 							_vm->_inter->funcBlock(0);
+							_script->pop();
 
-							_script->seek(startPos);
 						}
 
 						_lastCollKey = key;
 						if ((_lastCollKey != 0) && ((_lastCollId & 0x8000) != 0)) {
-							uint32 startPos = _script->pos();
-
-							_script->seek(_collisionAreas[_lastCollAreaIndex].funcEnter);
 
+							_script->call(_collisionAreas[_lastCollAreaIndex].funcEnter);
 							_vm->_inter->funcBlock(0);
+							_script->pop();
 
-							_script->seek(startPos);
 						}
 
 					}
diff --git a/engines/gob/game_v2.cpp b/engines/gob/game_v2.cpp
index 4ed9a49e8c..b9cda4832a 100644
--- a/engines/gob/game_v2.cpp
+++ b/engines/gob/game_v2.cpp
@@ -62,7 +62,7 @@ void Game_v2::playTot(int16 skipPlay) {
 	oldBreakFrom = _vm->_inter->_breakFromLevel;
 	oldCaptureCounter = _vm->_scenery->_pCaptureCounter;
 
-	uint32 startPos = _script->pos();
+	_script->push();
 
 	_vm->_inter->_nestLevel = &nestLevel;
 	_vm->_inter->_breakFromLevel = &breakFrom;
@@ -293,7 +293,7 @@ void Game_v2::playTot(int16 skipPlay) {
 	_vm->_inter->_breakFromLevel = oldBreakFrom;
 	_vm->_scenery->_pCaptureCounter = oldCaptureCounter;
 
-	_script->seek(startPos);
+	_script->pop();
 }
 
 void Game_v2::clearCollisions() {
diff --git a/engines/gob/inter_v1.cpp b/engines/gob/inter_v1.cpp
index bf24e8ef28..5cb74f2854 100644
--- a/engines/gob/inter_v1.cpp
+++ b/engines/gob/inter_v1.cpp
@@ -638,11 +638,7 @@ void Inter_v1::o1_freeFontToSprite() {
 }
 
 bool Inter_v1::o1_callSub(OpFuncParams &params) {
-	uint16 offset;
-
-	offset = _vm->_game->_script->readUint16();
-
-	uint32 startPos = _vm->_game->_script->pos();
+	uint16 offset = _vm->_game->_script->readUint16();
 
 	debugC(5, kDebugGameFlow, "tot = \"%s\", offset = %d",
 			_vm->_game->_curTotFile, offset);
@@ -666,14 +662,16 @@ bool Inter_v1::o1_callSub(OpFuncParams &params) {
 		return false;
 	}
 
-	_vm->_game->_script->seek(offset);
+	_vm->_game->_script->call(offset);
 
-	if ((params.counter == params.cmdCount) && (params.retFlag == 2))
+	if ((params.counter == params.cmdCount) && (params.retFlag == 2)) {
+		_vm->_game->_script->pop(false);
 		return true;
+	}
 
 	callSub(2);
 
-	_vm->_game->_script->seek(startPos);
+	_vm->_game->_script->pop();
 
 	return false;
 }
@@ -714,17 +712,19 @@ bool Inter_v1::o1_switch(OpFuncParams &params) {
 
 	checkSwitchTable(offset);
 
-	uint32 startPos = _vm->_game->_script->pos();
+	_vm->_game->_script->call(offset);
 
-	_vm->_game->_script->seek(offset);
 	if (offset == 0)
 		_vm->_game->_script->setFinished(true);
 
-	if ((params.counter == params.cmdCount) && (params.retFlag == 2))
+	if ((params.counter == params.cmdCount) && (params.retFlag == 2)) {
+		_vm->_game->_script->pop(false);
 		return true;
+	}
 
 	funcBlock(0);
-	_vm->_game->_script->seek(startPos);
+
+	_vm->_game->_script->pop();
 
 	return false;
 }
@@ -804,10 +804,9 @@ bool Inter_v1::o1_if(OpFuncParams &params) {
 		if ((params.counter == params.cmdCount) && (params.retFlag == 2))
 			return true;
 
-		uint32 startPos = _vm->_game->_script->pos();
+		_vm->_game->_script->push();
 		funcBlock(0);
-
-		_vm->_game->_script->seek(startPos);
+		_vm->_game->_script->pop();
 
 		_vm->_game->_script->skip(_vm->_game->_script->peekUint16(2) + 2);
 
@@ -830,11 +829,9 @@ bool Inter_v1::o1_if(OpFuncParams &params) {
 		if ((params.counter == params.cmdCount) && (params.retFlag == 2))
 			return true;
 
-		uint32 startPos = _vm->_game->_script->pos();
-
+		_vm->_game->_script->push();
 		funcBlock(0);
-
-		_vm->_game->_script->seek(startPos);
+		_vm->_game->_script->pop();
 
 		_vm->_game->_script->skip(_vm->_game->_script->peekUint16(2) + 2);
 	}
diff --git a/engines/gob/inter_v6.cpp b/engines/gob/inter_v6.cpp
index 1fc073d2ff..5b94fe91c4 100644
--- a/engines/gob/inter_v6.cpp
+++ b/engines/gob/inter_v6.cpp
@@ -263,14 +263,14 @@ bool Inter_v6::o6_assign(OpFuncParams &params) {
 	if (size != 0) {
 		int16 src;
 
-		uint32 startPos = _vm->_game->_script->pos();
+		_vm->_game->_script->push();
 
 		src = _vm->_game->_script->readVarIndex(&size, 0);
 
 		memcpy(_vm->_inter->_variables->getAddressOff8(dest),
 				_vm->_inter->_variables->getAddressOff8(src), size * 4);
 
-		_vm->_game->_script->seek(startPos);
+		_vm->_game->_script->pop();
 
 		evalExpr(&src);
 
diff --git a/engines/gob/script.cpp b/engines/gob/script.cpp
index f731ed33e9..e068ae5ff3 100644
--- a/engines/gob/script.cpp
+++ b/engines/gob/script.cpp
@@ -358,4 +358,33 @@ void Script::cuckoo(byte *totData, uint32 totSize) {
 	_totSize = totSize;
 }
 
+void Script::push() {
+	CallEntry currentCall;
+
+	currentCall.totData = _totData;
+	currentCall.totPtr = _totPtr;
+	currentCall.totSize = _totSize;
+	currentCall.finished = _finished;
+
+	_callStack.push(currentCall);
+}
+
+void Script::pop(bool ret) {
+	assert(!_callStack.empty());
+
+	CallEntry lastCall = _callStack.pop();
+
+	if (ret) {
+		_totData = lastCall.totData;
+		_totPtr = lastCall.totPtr;
+		_totSize = lastCall.totSize;
+		_finished = lastCall.finished;
+	}
+}
+
+void Script::call(uint32 offset) {
+	push();
+	seek(offset);
+}
+
 } // End of namespace Gob
diff --git a/engines/gob/script.h b/engines/gob/script.h
index c88d284e82..5c689bd991 100644
--- a/engines/gob/script.h
+++ b/engines/gob/script.h
@@ -27,6 +27,7 @@
 #define GOB_SCRIPT_H
 
 #include "common/str.h"
+#include "common/stack.h"
 
 namespace Gob {
 
@@ -89,6 +90,10 @@ public:
 
 	void cuckoo(byte *totData, uint32 totSize);
 
+	void push();
+	void pop(bool ret = true);
+	void call(uint32 offset);
+
 /*	byte *loadExtData(int16 dataId, int16 *pResWidth, int16 *pResHeight, uint32 *dataSize = 0);
 	byte *loadTotResource(int16 id, int16 *dataSize = 0, int16 *width = 0, int16 *height = 0);
 
@@ -100,6 +105,13 @@ public:
 	int16 openLocTextFile(char *locTextFile, int language);*/
 
 private:
+	struct CallEntry {
+		byte *totData;
+		byte *totPtr;
+		uint32 totSize;
+		bool finished;
+	};
+
 	GobEngine *_vm;
 	Parse *_parser;
 
@@ -115,6 +127,8 @@ private:
 
 	int16 _lomHandle;
 
+	Common::Stack<CallEntry> _callStack;
+
 	bool loadTOT(const Common::String &fileName);
 	bool loadLOM(const Common::String &fileName);