From 3203e597b9546d85c3eff887ea4f01e051ebbba0 Mon Sep 17 00:00:00 2001
From: jacob1 <jfu614@gmail.com>
Date: Wed, 10 Jul 2013 16:59:10 -0400
Subject: [PATCH] fix piston bugs, fix crashes, don't use bluescreens when
 compiled with debug mode in visual studio

---
 src/PowderToySDL.cpp             |  2 +-
 src/gui/preview/PreviewModel.cpp |  4 ++--
 src/simulation/Simulation.cpp    |  2 +-
 src/simulation/elements/PSTN.cpp | 10 +++++-----
 4 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/src/PowderToySDL.cpp b/src/PowderToySDL.cpp
index f49ed55a0..0f79d9e0f 100644
--- a/src/PowderToySDL.cpp
+++ b/src/PowderToySDL.cpp
@@ -779,7 +779,7 @@ int main(int argc, char * argv[])
 	engine->Begin(XRES+BARSIZE, YRES+MENUSIZE);
 	engine->SetFastQuit(Client::Ref().GetPrefBool("FastQuit", true));
 
-#ifndef DEBUG
+#if !defined(DEBUG) && !defined(_DEBUG)
 	//Get ready to catch any dodgy errors
 	signal(SIGSEGV, SigHandler);
 	signal(SIGFPE, SigHandler);
diff --git a/src/gui/preview/PreviewModel.cpp b/src/gui/preview/PreviewModel.cpp
index 5903f7793..8d5d574de 100644
--- a/src/gui/preview/PreviewModel.cpp
+++ b/src/gui/preview/PreviewModel.cpp
@@ -252,7 +252,7 @@ void PreviewModel::Update()
 		delete updateSaveDataInfo;
 		updateSaveDataInfo = NULL;
 
-		if (save)
+		if (save && saveData)
 		{
 			commentsTotal = save->Comments;
 			try
@@ -279,7 +279,7 @@ void PreviewModel::Update()
 		delete updateSaveInfoInfo;
 		updateSaveInfoInfo = NULL;
 
-		if (save)
+		if (save && saveData)
 		{
 			commentsTotal = save->Comments;
 			try
diff --git a/src/simulation/Simulation.cpp b/src/simulation/Simulation.cpp
index 5d40529c1..747a019d5 100644
--- a/src/simulation/Simulation.cpp
+++ b/src/simulation/Simulation.cpp
@@ -308,7 +308,7 @@ void Simulation::Restore(const Snapshot & snap)
 {
 	parts_lastActiveIndex = NPART-1; 
 
-	for(int i; i<NPART; i++)
+	for(int i = 0; i<NPART; i++)
 		elementCount[i] = 0;
 
 	std::copy(snap.AirPressure.begin(), snap.AirPressure.end(), &pv[0][0]);
diff --git a/src/simulation/elements/PSTN.cpp b/src/simulation/elements/PSTN.cpp
index ba2ba858c..d880ee8ce 100644
--- a/src/simulation/elements/PSTN.cpp
+++ b/src/simulation/elements/PSTN.cpp
@@ -168,7 +168,7 @@ int Element_PSTN::update(UPDATE_FUNC_ARGS)
 int Element_PSTN::CanMoveStack(Simulation * sim, int stackX, int stackY, int directionX, int directionY, int maxSize, int amount, bool retract, int block)
 {
 	int posX, posY, r, spaces = 0, currentPos = 0;
-	if (amount == 0)
+	if (amount <= 0)
 		return 0;
 	for(posX = stackX, posY = stackY; currentPos < maxSize + amount; posX += directionX, posY += directionY) {
 		if (!(posX < XRES && posY < YRES && posX >= 0 && posY >= 0)) {
@@ -176,14 +176,14 @@ int Element_PSTN::CanMoveStack(Simulation * sim, int stackX, int stackY, int dir
 		}
 		r = sim->pmap[posY][posX];
 		if (sim->IsWallBlocking(posX, posY, 0) || (block && (r&0xFF) == block))
-			break;
+			return spaces;
 		if(!r) {
 			spaces++;
 			tempParts[currentPos++] = -1;
 			if(spaces >= amount)
 				break;
 		} else {
-			if(spaces < maxSize && !retract)
+			if(spaces < maxSize && currentPos < maxSize && (!retract || ((r&0xFF) == PT_FRME) && posX == stackX && posY == stackY))
 				tempParts[currentPos++] = r>>8;
 			else
 				return spaces;
@@ -212,7 +212,7 @@ int Element_PSTN::MoveStack(Simulation * sim, int stackX, int stackY, int direct
 			posY = stackY + (c*newY);
 			posX = stackX + (c*newX);
 			if (posX < XRES && posY < YRES && posX >= 0 && posY >= 0 && (sim->pmap[posY][posX]&0xFF) == PT_FRME) {
-				int val = CanMoveStack(sim, posX+realDirectionX, posY+realDirectionY, realDirectionX, realDirectionY, maxSize, amount, retract, block);
+				int val = CanMoveStack(sim, posX, posY, realDirectionX, realDirectionY, maxSize, amount, retract, block);
 				if(val < amount)
 					amount = val;
 			} else {
@@ -224,7 +224,7 @@ int Element_PSTN::MoveStack(Simulation * sim, int stackX, int stackY, int direct
 			posY = stackY - (c*newY);
 			posX = stackX - (c*newX);
 			if (posX < XRES && posY < YRES && posX >= 0 && posY >= 0 && (sim->pmap[posY][posX]&0xFF) == PT_FRME) {
-				int val = CanMoveStack(sim, posX+realDirectionX, posY+realDirectionY, realDirectionX, realDirectionY, maxSize, amount, retract, block);
+				int val = CanMoveStack(sim, posX, posY, realDirectionX, realDirectionY, maxSize, amount, retract, block);
 				if(val < amount)
 					amount = val;
 			} else {