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  • Gravity stops when side-collision detected

    - by Adrian Marszalek
    Please, look at this GIF: The label on the animation says "Move button is pressed, then released". And you can see when it's pressed (and player's getCenterY() is above wall getCenterY()), gravity doesn't work. I'm trying to fix it since yesterday, but I can't. All methods are called from game loop. public void move() { if (left) { switch (game.currentLevel()) { case 1: for (int i = 0; i < game.lvl1.getX().length; i++) game.lvl1.getX()[i] += game.physic.xVel; break; } } else if (right) { switch (game.currentLevel()) { case 1: for (int i = 0; i < game.lvl1.getX().length; i++) game.lvl1.getX()[i] -= game.physic.xVel; break; } } } int manCenterX, manCenterY, boxCenterX, boxCenterY; //gravity stop public void checkCollision() { for (int i = 0; i < game.lvl1.getX().length; i++) { manCenterX = (int) game.man.getBounds().getCenterX(); manCenterY = (int) game.man.getBounds().getCenterY(); if (game.man.getBounds().intersects(game.lvl1.getBounds(i))) { boxCenterX = (int) game.lvl1.getBounds(i).getCenterX(); boxCenterY = (int) game.lvl1.getBounds(i).getCenterY(); if (manCenterY - boxCenterY > 0 || manCenterY - boxCenterY < 0) { game.man.setyPos(-2f); game.man.isFalling = false; } } } } //left side of walls public void colliLeft() { for (int i = 0; i < game.lvl1.getX().length; i++) { if (game.man.getBounds().intersects(game.lvl1.getBounds(i))) { if (manCenterX - boxCenterX < 0) { for (int i1 = 0; i1 < game.lvl1.getX().length; i1++) { game.lvl1.getX()[i1] += game.physic.xVel; game.man.isFalling = true; } } } } } //right side of walls public void colliRight() { for (int i = 0; i < game.lvl1.getX().length; i++) { if (game.man.getBounds().intersects(game.lvl1.getBounds(i))) { if (manCenterX - boxCenterX > 0) { for (int i1 = 0; i1 < game.lvl1.getX().length; i1++) { game.lvl1.getX()[i1] += -game.physic.xVel; game.man.isFalling = true; } } } } } public void gravity() { game.man.setyPos(yVel); } //not called from gameloop: public void setyPos(float yPos) { this.yPos += yPos; }

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  • Delegates in c#

    - by Jalpesh P. Vadgama
    I have used delegates in my programming since C# 2.0. But I have seen there are lots of confusion going on with delegates so I have decided to blog about it. In this blog I will explain about delegate basics and use of delegates in C#. What is delegate? We can say a delegate is a type safe function pointer which holds methods reference in object. As per MSDN it's a type that references to a method. So you can assign more than one methods to delegates with same parameter and same return type. Following is syntax for the delegate public delegate int Calculate(int a, int b); Here you can see the we have defined the delegate with two int parameter and integer parameter as return parameter. Now any method that matches this parameter can be assigned to above delegates. To understand the functionality of delegates let’s take a following simple example. using System; namespace Delegates { class Program { public delegate int CalculateNumber(int a, int b); static void Main(string[] args) { int a = 5; int b = 5; CalculateNumber addNumber = new CalculateNumber(AddNumber); Console.WriteLine(addNumber(5, 6)); Console.ReadLine(); } public static int AddNumber(int a, int b) { return a + b; } } } Here in the above code you can see that I have created a object of CalculateNumber delegate and I have assigned the AddNumber static method to it. Where you can see in ‘AddNumber’ static method will just return a sum of two numbers. After that I am calling method with the help of the delegates and printing out put to the console application. Now let’s run the application and following is the output as expected. That’s it. You can see the out put of delegates after adding a number. This delegates can be used in variety of scenarios. Like in web application we can use it to update one controls properties from another control’s action. Same you can also call a delegates whens some UI interaction done like button clicked. Hope you liked it. Stay tuned for more. In next post I am going to explain about multicast delegates. Till then happy programming.

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  • Spritesheet per pixel collision XNA

    - by Jixi
    So basically i'm using this: public bool IntersectPixels(Rectangle rectangleA, Color[] dataA,Rectangle rectangleB, Color[] dataB) { int top = Math.Max(rectangleA.Top, rectangleB.Top); int bottom = Math.Min(rectangleA.Bottom, rectangleB.Bottom); int left = Math.Max(rectangleA.Left, rectangleB.Left); int right = Math.Min(rectangleA.Right, rectangleB.Right); for (int y = top; y < bottom; y++) { for (int x = left; x < right; x++) { Color colorA = dataA[(x - rectangleA.Left) + (y - rectangleA.Top) * rectangleA.Width]; Color colorB = dataB[(x - rectangleB.Left) + (y - rectangleB.Top) * rectangleB.Width]; if (colorA.A != 0 && colorB.A != 0) { return true; } } } return false; } In order to detect collision, but i'm unable to figure out how to use it with animated sprites. This is my animation update method: public void AnimUpdate(GameTime gameTime) { if (!animPaused) { animTimer += (float)gameTime.ElapsedGameTime.TotalMilliseconds; if (animTimer > animInterval) { currentFrame++; animTimer = 0f; } if (currentFrame > endFrame || endFrame <= currentFrame || currentFrame < startFrame) { currentFrame = startFrame; } objRect = new Rectangle(currentFrame * TextureWidth, frameRow * TextureHeight, TextureWidth, TextureHeight); origin = new Vector2(objRect.Width / 2, objRect.Height / 2); } } Which works with multiple rows and columns. and how i call the intersect: public bool IntersectPixels(Obj me, Vector2 pos, Obj o) { Rectangle collisionRect = new Rectangle(me.objRect.X, me.objRect.Y, me.objRect.Width, me.objRect.Height); collisionRect.X += (int)pos.X; collisionRect.Y += (int)pos.Y; if (IntersectPixels(collisionRect, me.TextureData, o.objRect, o.TextureData)) { return true; } return false; } Now my guess is that i have to update the textureData everytime the frame changes, no? If so then i already tried it and miserably failed doing so :P Any hints, advices? If you need to see any more of my code just let me know and i'll update the question. Updated almost functional collisionRect: collisionRect = new Rectangle((int)me.Position.X, (int)me.Position.Y, me.Texture.Width / (int)((me.frameCount - 1) * me.TextureWidth), me.Texture.Height); What it does now is "move" the block up 50%, shouldn't be too hard to figure out. Update: Alright, so here's a functional collision rectangle(besides the height issue) collisionRect = new Rectangle((int)me.Position.X, (int)me.Position.Y, me.TextureWidth / (int)me.frameCount - 1, me.TextureHeight); Now the problem is that using breakpoints i found out that it's still not getting the correct color values of the animated sprite. So it detects properly but the color values are always: R:0 G:0 B:0 A:0 ??? disregard that, it's not true afterall =P For some reason now the collision area height is only 1 pixel..

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  • Tile-based 2D collision detection problems

    - by Vee
    I'm trying to follow this tutorial http://www.tonypa.pri.ee/tbw/tut05.html to implement real-time collisions in a tile-based world. I find the center coordinates of my entities thanks to these properties: public float CenterX { get { return X + Width / 2f; } set { X = value - Width / 2f; } } public float CenterY { get { return Y + Height / 2f; } set { Y = value - Height / 2f; } } Then in my update method, in the player class, which is called every frame, I have this code: public override void Update() { base.Update(); int downY = (int)Math.Floor((CenterY + Height / 2f - 1) / 16f); int upY = (int)Math.Floor((CenterY - Height / 2f) / 16f); int leftX = (int)Math.Floor((CenterX + Speed * NextX - Width / 2f) / 16f); int rightX = (int)Math.Floor((CenterX + Speed * NextX + Width / 2f - 1) / 16f); bool upleft = Game.CurrentMap[leftX, upY] != 1; bool downleft = Game.CurrentMap[leftX, downY] != 1; bool upright = Game.CurrentMap[rightX, upY] != 1; bool downright = Game.CurrentMap[rightX, downY] != 1; if(NextX == 1) { if (upright && downright) CenterX += Speed; else CenterX = (Game.GetCellX(CenterX) + 1)*16 - Width / 2f; } } downY, upY, leftX and rightX should respectively find the lowest Y position, the highest Y position, the leftmost X position and the rightmost X position. I add + Speed * NextX because in the tutorial the getMyCorners function is called with these parameters: getMyCorners (ob.x+ob.speed*dirx, ob.y, ob); The GetCellX and GetCellY methods: public int GetCellX(float mX) { return (int)Math.Floor(mX / SGame.Camera.TileSize); } public int GetCellY(float mY) { return (int)Math.Floor(mY / SGame.Camera.TileSize); } The problem is that the player "flickers" while hitting a wall, and the corner detection doesn't even work correctly since it can overlap walls that only hit one of the corners. I do not understand what is wrong. In the tutorial the ob.x and ob.y fields should be the same as my CenterX and CenterY properties, and the ob.width and ob.height should be the same as Width / 2f and Height / 2f. However it still doesn't work. Thanks for your help.

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  • Is this proper OO design for C++?

    - by user121917
    I recently took a software processes course and this is my first time attempting OO design on my own. I am trying to follow OO design principles and C++ conventions. I attempted and gave up on MVC for this application, but I am trying to "decouple" my classes such that they can be easily unit-tested and so that I can easily change the GUI library used and/or the target OS. At this time, I have finished designing classes but have not yet started implementing methods. The function of the software is to log all packets sent and received, and display them on the screen (like WireShark, but for one local process only). The software accomplishes this by hooking the send() and recv() functions in winsock32.dll, or some other pair of analogous functions depending on what the intended Target is. The hooks add packets to SendPacketList/RecvPacketList. The GuiLogic class starts a thread which checks for new packets. When new packets are found, it utilizes the PacketFilter class to determine the formatting for the new packet, and then sends it to MainWindow, a native win32 window (with intent to later port to Qt).1 Full size image of UML class diagram Here are my classes in skeleton/header form (this is my actual code): class PacketModel { protected: std::vector<byte> data; int id; public: PacketModel(); PacketModel(byte* data, unsigned int size); PacketModel(int id, byte* data, unsigned int size); int GetLen(); bool IsValid(); //len >= sizeof(opcode_t) opcode_t GetOpcode(); byte* GetData(); //returns &(data[0]) bool GetData(byte* outdata, int maxlen); void SetData(byte* pdata, int len); int GetId(); void SetId(int id); bool ParseData(char* instr); bool StringRepr(char* outstr); byte& operator[] (const int index); }; class SendPacket : public PacketModel { protected: byte* returnAddy; public: byte* GetReturnAddy(); void SetReturnAddy(byte* addy); }; class RecvPacket : public PacketModel { protected: byte* callAddy; public: byte* GetCallAddy(); void SetCallAddy(byte* addy); }; //problem: packets may be added to list at any time by any number of threads //solution: critical section associated with each packet list class Synch { public: void Enter(); void Leave(); }; template<class PacketType> class PacketList { private: static const int MAX_STORED_PACKETS = 1000; public: static const int DEFAULT_SHOWN_PACKETS = 100; private: vector<PacketType> list; Synch synch; //wrapper for critical section public: void AddPacket(PacketType* packet); PacketType* GetPacket(int id); int TotalPackets(); }; class SendPacketList : PacketList<SendPacket> { }; class RecvPacketList : PacketList<RecvPacket> { }; class Target //one socket { bool Send(SendPacket* packet); bool Inject(RecvPacket* packet); bool InitSendHook(SendPacketList* sendList); bool InitRecvHook(RecvPacketList* recvList); }; class FilterModel { private: opcode_t opcode; int colorID; bool bFilter; char name[41]; }; class FilterFile { private: FilterModel filter; public: void Save(); void Load(); FilterModel* GetFilter(opcode_t opcode); }; class PacketFilter { private: FilterFile filters; public: bool IsFiltered(opcode_t opcode); bool GetName(opcode_t opcode, char* namestr); //return false if name does not exist COLORREF GetColor(opcode_t opcode); //return default color if no custom color }; class GuiLogic { private: SendPacketList sendList; RecvPacketList recvList; PacketFilter packetFilter; void GetPacketRepr(PacketModel* packet); void ReadNew(); void AddToWindow(); public: void Refresh(); //called from thread void GetPacketInfo(int id); //called from MainWindow }; I'm looking for a general review of my OO design, use of UML, and use of C++ features. I especially just want to know if I'm doing anything considerably wrong. From what I've read, design review is on-topic for this site (and off-topic for the Code Review site). Any sort of feedback is greatly appreciated. Thanks for reading this.

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  • Problem displaying tiles using tiled map loader with SFML

    - by user1905192
    I've been searching fruitlessly for what I did wrong for the past couple of days and I was wondering if anyone here could help me. My program loads my tile map, but then crashes with an assertion error. The program breaks at this line: spacing = atoi(tilesetElement-Attribute("spacing")); Here's my main game.cpp file. #include "stdafx.h" #include "Game.h" #include "Ball.h" #include "level.h" using namespace std; Game::Game() { gameState=NotStarted; ball.setPosition(500,500); level.LoadFromFile("meow.tmx"); } void Game::Start() { if (gameState==NotStarted) { window.create(sf::VideoMode(1024,768,320),"game"); view.reset(sf::FloatRect(0,0,1000,1000));//ball drawn at 500,500 level.SetDrawingBounds(sf::FloatRect(view.getCenter().x-view.getSize().x/2,view.getCenter().y-view.getSize().y/2,view.getSize().x, view.getSize().y)); window.setView(view); gameState=Playing; } while(gameState!=Exiting) { GameLoop(); } window.close(); } void Game::GameLoop() { sf::Event CurrentEvent; window.pollEvent(CurrentEvent); switch(gameState) { case Playing: { window.clear(sf::Color::White); window.setView(view); if (CurrentEvent.type==sf::Event::Closed) { gameState=Exiting; } if ( !ball.IsFalling() &&!ball.IsJumping() &&sf::Keyboard::isKeyPressed(sf::Keyboard::Space)) { ball.setJState(); } ball.Update(view); level.Draw(window); ball.Draw(window); window.display(); break; } } } And here's the file where the error happens: /********************************************************************* Quinn Schwab 16/08/2010 SFML Tiled Map Loader The zlib license has been used to make this software fully compatible with SFML. See http://www.sfml-dev.org/license.php This software is provided 'as-is', without any express or implied warranty. In no event will the authors be held liable for any damages arising from the use of this software. Permission is granted to anyone to use this software for any purpose, including commercial applications, and to alter it and redistribute it freely, subject to the following restrictions: 1. The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation would be appreciated but is not required. 2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software. 3. This notice may not be removed or altered from any source distribution. *********************************************************************/ #include "level.h" #include <iostream> #include "tinyxml.h" #include <fstream> int Object::GetPropertyInt(std::string name) { int i; i = atoi(properties[name].c_str()); return i; } float Object::GetPropertyFloat(std::string name) { float f; f = strtod(properties[name].c_str(), NULL); return f; } std::string Object::GetPropertyString(std::string name) { return properties[name]; } Level::Level() { //ctor } Level::~Level() { //dtor } using namespace std; bool Level::LoadFromFile(std::string filename) { TiXmlDocument levelFile(filename.c_str()); if (!levelFile.LoadFile()) { std::cout << "Loading level \"" << filename << "\" failed." << std::endl; return false; } //Map element. This is the root element for the whole file. TiXmlElement *map; map = levelFile.FirstChildElement("map"); //Set up misc map properties. width = atoi(map->Attribute("width")); height = atoi(map->Attribute("height")); tileWidth = atoi(map->Attribute("tilewidth")); tileHeight = atoi(map->Attribute("tileheight")); //Tileset stuff TiXmlElement *tilesetElement; tilesetElement = map->FirstChildElement("tileset"); firstTileID = atoi(tilesetElement->Attribute("firstgid")); spacing = atoi(tilesetElement->Attribute("spacing")); margin = atoi(tilesetElement->Attribute("margin")); //Tileset image TiXmlElement *image; image = tilesetElement->FirstChildElement("image"); std::string imagepath = image->Attribute("source"); if (!tilesetImage.loadFromFile(imagepath))//Load the tileset image { std::cout << "Failed to load tile sheet." << std::endl; return false; } tilesetImage.createMaskFromColor(sf::Color(255, 0, 255)); tilesetTexture.loadFromImage(tilesetImage); tilesetTexture.setSmooth(false); //Columns and rows (of tileset image) int columns = tilesetTexture.getSize().x / tileWidth; int rows = tilesetTexture.getSize().y / tileHeight; std::vector <sf::Rect<int> > subRects;//container of subrects (to divide the tilesheet image up) //tiles/subrects are counted from 0, left to right, top to bottom for (int y = 0; y < rows; y++) { for (int x = 0; x < columns; x++) { sf::Rect <int> rect; rect.top = y * tileHeight; rect.height = y * tileHeight + tileHeight; rect.left = x * tileWidth; rect.width = x * tileWidth + tileWidth; subRects.push_back(rect); } } //Layers TiXmlElement *layerElement; layerElement = map->FirstChildElement("layer"); while (layerElement) { Layer layer; if (layerElement->Attribute("opacity") != NULL)//check if opacity attribute exists { float opacity = strtod(layerElement->Attribute("opacity"), NULL);//convert the (string) opacity element to float layer.opacity = 255 * opacity; } else { layer.opacity = 255;//if the attribute doesnt exist, default to full opacity } //Tiles TiXmlElement *layerDataElement; layerDataElement = layerElement->FirstChildElement("data"); if (layerDataElement == NULL) { std::cout << "Bad map. No layer information found." << std::endl; } TiXmlElement *tileElement; tileElement = layerDataElement->FirstChildElement("tile"); if (tileElement == NULL) { std::cout << "Bad map. No tile information found." << std::endl; return false; } int x = 0; int y = 0; while (tileElement) { int tileGID = atoi(tileElement->Attribute("gid")); int subRectToUse = tileGID - firstTileID;//Work out the subrect ID to 'chop up' the tilesheet image. if (subRectToUse >= 0)//we only need to (and only can) create a sprite/tile if there is one to display { sf::Sprite sprite;//sprite for the tile sprite.setTexture(tilesetTexture); sprite.setTextureRect(subRects[subRectToUse]); sprite.setPosition(x * tileWidth, y * tileHeight); sprite.setColor(sf::Color(255, 255, 255, layer.opacity));//Set opacity of the tile. //add tile to layer layer.tiles.push_back(sprite); } tileElement = tileElement->NextSiblingElement("tile"); //increment x, y x++; if (x >= width)//if x has "hit" the end (right) of the map, reset it to the start (left) { x = 0; y++; if (y >= height) { y = 0; } } } layers.push_back(layer); layerElement = layerElement->NextSiblingElement("layer"); } //Objects TiXmlElement *objectGroupElement; if (map->FirstChildElement("objectgroup") != NULL)//Check that there is atleast one object layer { objectGroupElement = map->FirstChildElement("objectgroup"); while (objectGroupElement)//loop through object layers { TiXmlElement *objectElement; objectElement = objectGroupElement->FirstChildElement("object"); while (objectElement)//loop through objects { std::string objectType; if (objectElement->Attribute("type") != NULL) { objectType = objectElement->Attribute("type"); } std::string objectName; if (objectElement->Attribute("name") != NULL) { objectName = objectElement->Attribute("name"); } int x = atoi(objectElement->Attribute("x")); int y = atoi(objectElement->Attribute("y")); int width = atoi(objectElement->Attribute("width")); int height = atoi(objectElement->Attribute("height")); Object object; object.name = objectName; object.type = objectType; sf::Rect <int> objectRect; objectRect.top = y; objectRect.left = x; objectRect.height = y + height; objectRect.width = x + width; if (objectType == "solid") { solidObjects.push_back(objectRect); } object.rect = objectRect; TiXmlElement *properties; properties = objectElement->FirstChildElement("properties"); if (properties != NULL) { TiXmlElement *prop; prop = properties->FirstChildElement("property"); if (prop != NULL) { while(prop) { std::string propertyName = prop->Attribute("name"); std::string propertyValue = prop->Attribute("value"); object.properties[propertyName] = propertyValue; prop = prop->NextSiblingElement("property"); } } } objects.push_back(object); objectElement = objectElement->NextSiblingElement("object"); } objectGroupElement = objectGroupElement->NextSiblingElement("objectgroup"); } } else { std::cout << "No object layers found..." << std::endl; } return true; } Object Level::GetObject(std::string name) { for (int i = 0; i < objects.size(); i++) { if (objects[i].name == name) { return objects[i]; } } } void Level::SetDrawingBounds(sf::Rect<float> bounds) { drawingBounds = bounds; cout<<tileHeight; //Adjust the rect so that tiles are drawn just off screen, so you don't see them disappearing. drawingBounds.top -= tileHeight; drawingBounds.left -= tileWidth; drawingBounds.width += tileWidth; drawingBounds.height += tileHeight; } void Level::Draw(sf::RenderWindow &window) { for (int layer = 0; layer < layers.size(); layer++) { for (int tile = 0; tile < layers[layer].tiles.size(); tile++) { if (drawingBounds.contains(layers[layer].tiles[tile].getPosition().x, layers[layer].tiles[tile].getPosition().y)) { window.draw(layers[layer].tiles[tile]); } } } } I really hope that one of you can help me and I'm sorry if I've made any formatting issues. Thanks!

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  • rotate sprite and shooting bullets from the end of a cannon

    - by Alberto
    Hi all i have a problem in my Andengine code, I need , when I touch the screen, shoot a bullet from the cannon (in the same direction of the cannon) The cannon rotates perfectly but when I touch the screen the bullet is not created at the end of the turret This is my code: private void shootProjectile(final float pX, final float pY){ int offX = (int) (pX-canon.getSceneCenterCoordinates()[0]); int offY = (int) (pY-canon.getSceneCenterCoordinates()[1]); if (offX <= 0) return ; if(offY>=0) return; double X=canon.getX()+canon.getWidth()*0,5; double Y=canon.getY()+canon.getHeight()*0,5 ; final Sprite projectile; projectile = new Sprite( (float) X, (float) Y, mProjectileTextureRegion,this.getVertexBufferObjectManager() ); mMainScene.attachChild(projectile); int realX = (int) (mCamera.getWidth()+ projectile.getWidth()/2.0f); float ratio = (float) offY / (float) offX; int realY = (int) ((realX*ratio) + projectile.getY()); int offRealX = (int) (realX- projectile.getX()); int offRealY = (int) (realY- projectile.getY()); float length = (float) Math.sqrt((offRealX*offRealX)+(offRealY*offRealY)); float velocity = (float) 480.0f/1.0f; float realMoveDuration = length/velocity; MoveModifier modifier = new MoveModifier(realMoveDuration,projectile.getX(), realX, projectile.getY(), realY); projectile.registerEntityModifier(modifier); } @Override public boolean onSceneTouchEvent(Scene pScene, TouchEvent pSceneTouchEvent) { if (pSceneTouchEvent.getAction() == TouchEvent.ACTION_MOVE){ double dx = pSceneTouchEvent.getX() - canon.getSceneCenterCoordinates()[0]; double dy = pSceneTouchEvent.getY() - canon.getSceneCenterCoordinates()[1]; double Radius = Math.atan2(dy,dx); double Angle = Radius * 180 / Math.PI; canon.setRotation((float)Angle); return true; } else if (pSceneTouchEvent.getAction() == TouchEvent.ACTION_DOWN){ final float touchX = pSceneTouchEvent.getX(); final float touchY = pSceneTouchEvent.getY(); double dx = pSceneTouchEvent.getX() - canon.getSceneCenterCoordinates()[0]; double dy = pSceneTouchEvent.getY() - canon.getSceneCenterCoordinates()[1]; double Radius = Math.atan2(dy,dx); double Angle = Radius * 180 / Math.PI; canon.setRotation((float)Angle); shootProjectile(touchX, touchY); } return false; } Anyone know how to calculate the coordinates (X,Y) of the end of the barrel to draw the bullet?

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  • Efficient inline templates and C++

    - by Darryl Gove
    I've talked before about calling inline templates from C++, I've also talked about calling inline templates efficiently. This time I want to talk about efficiently calling inline templates from C++. The obvious starting point is that I need to declare the inline templates as being extern "C": extern "C" { int mytemplate(int); } This enables us to call it, but the call may not be very efficient because the compiler will treat it as a function call, and may produce suboptimal code based on that premise. So we need to add the no_side_effect pragma: extern "C" { int mytemplate(int); #pragma no_side_effect(mytemplate) } However, this may still not produce optimal code. We've discussed how the no_side_effect pragma cannot be combined with exceptions, well we know that the code cannot produce exceptions, but the compiler doesn't know that. If we tell the compiler that information it may be able to produce even better code. We can do this by adding the "throw()" keyword to the template declaration: extern "C" { int mytemplate(int) throw(); #pragma no_side_effect(mytemplate) } The following is an example of how these changes might improve performance. We can take our previous example code and migrate it to C++, adding the use of a try...catch construct: #include <iostream extern "C" { int lzd(int); #pragma no_side_effect(lzd) } int a; int c=0; class myclass { int routine(); }; int myclass::routine() { try { for(a=0; a<1000; a++) { c=lzd(c); } } catch(...) { std::cout << "Something happened" << std::endl; } return 0; } Compiling this produces a slightly suboptimal code sequence in the hot loop: $ CC -O -xtarget=T4 -S t.cpp t.il ... /* 0x0014 23 */ lzd %o0,%o0 /* 0x0018 21 */ add %l6,1,%l6 /* 0x001c */ cmp %l6,1000 /* 0x0020 */ bl,pt %icc,.L77000033 /* 0x0024 23 */ st %o0,[%l7] There's a store in the delay slot of the branch, so we're repeatedly storing data back to memory. If we change the function declaration to include "throw()", we get better code: $ CC -O -xtarget=T4 -S t.cpp t.il ... /* 0x0014 21 */ add %i1,1,%i1 /* 0x0018 23 */ lzd %o0,%o0 /* 0x001c 21 */ cmp %i1,999 /* 0x0020 */ ble,pt %icc,.L77000019 /* 0x0024 */ nop The store has gone, but the code is still suboptimal - there's a nop in the delay slot rather than useful work. However, it's good enough for this example. The point I'm making is that the compiler produces the better code with both the "throw()" and the no side effect pragma.

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  • Code Contracts: How they look after compiling?

    - by DigiMortal
    When you are using new tools that make also something at code level then it is good idea to check out what additions are made to code during compilation. Code contracts have simple syntax when we are writing code at Visual Studio but what happens after compilation? Are our methods same as they look in code or are they different after compilation? In this posting I will show you how code contracts look after compiling. In my previous examples about code contracts I used randomizer class with method called GetRandomFromRangeContracted. public int GetRandomFromRangeContracted(int min, int max) {     Contract.Requires<ArgumentOutOfRangeException>(         min < max,         "Min must be less than max"     );       Contract.Ensures(         Contract.Result<int>() >= min &&         Contract.Result<int>() <= max,         "Return value is out of range"     );       return _generator.Next(min, max); } Okay, it is nice to dream about similar code when we open our assembly with Reflector and disassemble it. But… this time we have something interesting. While reading this code don’t feel uncomfortable about the names of variables. This is disassembled code. .NET Framework internally allows these names. It is our compilators that doesn’t accept them when we are building our code. public int GetRandomFromRangeContracted(int min, int max) {     int Contract.Old(min);     int Contract.Old(max);     if (__ContractsRuntime.insideContractEvaluation <= 4)     {         try         {             __ContractsRuntime.insideContractEvaluation++;             __ContractsRuntime.Requires<ArgumentOutOfRangeException>(                min < max,                "Min must be less than max", "min < max");         }         finally         {             __ContractsRuntime.insideContractEvaluation--;         }     }     try     {         Contract.Old(min) = min;     }     catch (Exception exception1)     {         if (exception1 == null)         {             throw;         }     }     try     {         Contract.Old(max) = max;         catch (Exception exception2)     {         if (exception2 == null)         {             throw;         }     }     int CS$1$0000 = this._generator.Next(min, max);     int Contract.Result<int>() = CS$1$0000;     if (__ContractsRuntime.insideContractEvaluation <= 4)     {         try         {             __ContractsRuntime.insideContractEvaluation++;             __ContractsRuntime.Ensures(                (Contract.Result<int>() >= Contract.Old(min)) &&                (Contract.Result<int>() <= Contract.Old(max)),                "Return value is out of range",                "Contract.Result<int>() >= min && Contract.Result<int>() <= max");         }         finally         {             __ContractsRuntime.insideContractEvaluation--;         }     }     return Contract.Result<int>(); } As we can see then contracts are not simply if-then-else checks and exceptions throwing. We can see that there is counter that is incremented before checks and decremented after these whatever the result of check was. One thing that is annoying for me are null checks for exception1 and exception2. Is there really some situation possible when null is thrown instead of some instance that is Exception or that inherits from exception? Conclusion Code contracts are more complex mechanism that it seems when we look at it on our code level. Internally there are done more things than we know. I don’t say it is wrong, it is just good to know how our code looks after compiling. Looking at this example it is sure we need also performance tests for contracted code to see how heavy is their impact to system performance when we run code that makes heavy use of code contracts.

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  • Issue with DFS imlemtation in objetive-c

    - by Hemant
    i am trying to to do something like this Below is my code: -(id) init{ if( (self=[super init]) ) { bubbles_Arr = [[NSMutableArray alloc] initWithCapacity: 9]; [bubbles_Arr insertObject:[NSMutableArray arrayWithObjects:@"1",@"1",@"1",@"1",@"1",nil] atIndex:0]; [bubbles_Arr insertObject:[NSMutableArray arrayWithObjects:@"3",@"3",@"5",@"5",@"1",nil] atIndex:1]; [bubbles_Arr insertObject:[NSMutableArray arrayWithObjects:@"5",@"3",@"5",@"3",@"1",nil] atIndex:2]; [bubbles_Arr insertObject:[NSMutableArray arrayWithObjects:@"5",@"3",@"5",@"3",@"1",nil] atIndex:3]; [bubbles_Arr insertObject:[NSMutableArray arrayWithObjects:@"1",@"1",@"1",@"1",@"1",nil] atIndex:4]; [bubbles_Arr insertObject:[NSMutableArray arrayWithObjects:@"5",@"5",@"3",@"5",@"1",nil] atIndex:5]; [bubbles_Arr insertObject:[NSMutableArray arrayWithObjects:@"5",@"5",@"5",@"5",@"5",nil] atIndex:6]; [bubbles_Arr insertObject:[NSMutableArray arrayWithObjects:@"5",@"5",@"5",@"5",@"5",nil] atIndex:7]; [bubbles_Arr insertObject:[NSMutableArray arrayWithObjects:@"5",@"5",@"5",@"5",@"5",nil] atIndex:8]; NOCOLOR = @"-1"; R = 9; C = 5; [NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:@selector(testting) userInfo:Nil repeats:NO]; } return self; } -(void)testting{ // NSLog(@"dataArray---- %@",dataArray.description); int startR = 0; int startC = 0; int color = 1 ;// red // NSString *color = @"5"; //reset visited matrix to false. for(int i = 0; i < R; i++) for(int j = 0; j < C; j++) visited[i][j] = FALSE; //reset count count = 0; [self dfs:startR :startC :color :false]; NSLog(@"count--- %d",count); NSLog(@"test--- %@",bubbles_Arr); } -(void)dfs:(int)ro:(int)co:(int)colori:(BOOL)set{ for(int dr = -1; dr <= 1; dr++) for(int dc = -1; dc <= 1; dc++) if((dr == 0 ^ dc == 0) && [self ok:ro+dr :co+dc]) // 4 neighbors { int nr = ro+dr; int nc = co+dc; NSLog(@"-- %d ---- %d",[[[bubbles_Arr objectAtIndex:nr] objectAtIndex:nc] integerValue],colori); if ((([[[bubbles_Arr objectAtIndex:nr] objectAtIndex:nc] integerValue]==1 || [[[bubbles_Arr objectAtIndex:nr] objectAtIndex:nc] isEqualToString:@"1"]) && !visited[nr][nc])) { visited[nr][nc] = true; count++; [self dfs:nr :nc :colori :set]; if(count>2) { [[bubbles_Arr objectAtIndex:nr] replaceObjectAtIndex:nc withObject:NOCOLOR]; [bubbles[nc+1][nr+1] setTexture:[[CCTextureCache sharedTextureCache] addImage:@"gray_tiger.png"]]; } } } } -(BOOL)ok:(int)r:(int)c{ return r >= 0 && r < R && c >= 0 && c < C; } But it's only working for left to right,not working for right to left. And it is also skipping first object. Thanks in advance.

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  • SFML 2.0 Too Many Variables in Class Preventing Draw To Screen

    - by Josh
    This is a very strange phenomenon to me. I have a class definition for a game, but when I add another variable to the class, the draw method does not print everything to the screen. It will be easier understood showing the code and output. Code for good draw output: class board { protected: RectangleShape rect; int top, left; int i, j; int rowSelect, columnSelect; CircleShape circleArr[4][10]; CircleShape codeArr[4]; CircleShape keyArr[4][10]; //int pegPresent[4]; public: board(void); void draw(RenderWindow& Window); int mouseOver(RenderWindow& Window); void placePeg(RenderWindow& Window, int pegSelect); }; Screen: Code for missing draw: class board { protected: RectangleShape rect; int top, left; int i, j; int rowSelect, columnSelect; CircleShape circleArr[4][10]; CircleShape codeArr[4]; CircleShape keyArr[4][10]; int pegPresent[4]; public: board(void); void draw(RenderWindow& Window); int mouseOver(RenderWindow& Window); void placePeg(RenderWindow& Window, int pegSelect); }; Screen: As you can see, all I do is un-comment the protected array and most of the pegs are gone from the right hand side. I have checked and made sure that I didn't accidentally created a variable with that name already. I haven't used it anywhere. Why does it not draw the remaining pegs as it should? My only thought is that maybe I am declaring too many variables for the class, but that doesn't really make sense to me. Any thoughts and help is greatly appreciated.

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  • Help parsing long (3.5mil lines) text file, line by line and storing data, need a strategy

    - by Jarrod
    This is a question about solving a particular problem I am struggling with, I am parsing a long list of text data, line by line for a business app in PHP (cron script on the CLI). The file follows the format: HD: Some text here {text here too} DC: A description here DC: the description continues here DC: and it ends here. DT: 2012-08-01 HD: Next header here {supplemental text} ... this repeats over and over for a few hundred megs I have to read each line, parse out the HD: line and grab the text on this line. I then compare this text against data stored in a database. When a match is found, I want to then record the following DC: lines that succeed the matched HD:. Pseudo code: while ( the_file_pointer_isnt_end_of_file) { line = getCurrentLineFromFile title = parseTitleFrom(line) matched = searchForMatchInDB(line) if ( matched ) { recordTheDCLines // <- Best way to do this? } } My problem is that because I am reading line by line, what is the best way to trigger the script to start saving DC lines, and then when they are finished save them to the database? I have a vague idea, but have yet to properly implement it. I would love to hear the communities ideas\suggestions! Thank you.

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  • Can I get a C++ Compiler to instantiate objects at compile time

    - by gam3
    I am writing some code that has a very large number of reasonably simple objects and I would like them the be created at compile time. I would think that a compiler would be able to do this, but I have not been able to figure out how. In C I could do the the following: #include <stdio.h> typedef struct data_s { int a; int b; char *c; } info; info list[] = { 1, 2, "a", 3, 4, "b", }; main() { int i; for (i = 0; i < sizeof(list)/sizeof(*list); i++) { printf("%d %s\n", i, list[i].c); } } Using #C++* each object has it constructor called rather than just being layed out in memory. #include <iostream> using std::cout; using std::endl; class Info { const int a; const int b; const char *c; public: Info(const int, const int, const char *); const int get_a() { return a; }; const int get_b() { return b; }; const char *get_c() const { return c; }; }; Info::Info(const int a, const int b, const char *c) : a(a), b(b), c(c) {}; Info list[] = { Info(1, 2, "a"), Info(3, 4, "b"), }; main() { for (int i = 0; i < sizeof(list)/sizeof(*list); i++) { cout << i << " " << list[i].get_c() << endl; } } I just don't see what information is not available for the compiler to completely instantiate these objects at compile time, so I assume I am missing something.

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  • Is it OK to repeat code for unit tests?

    - by Pete
    I wrote some sorting algorithms for a class assignment and I also wrote a few tests to make sure the algorithms were implemented correctly. My tests are only like 10 lines long and there are 3 of them but only 1 line changes between the 3 so there is a lot of repeated code. Is it better to refactor this code into another method that is then called from each test? Wouldn't I then need to write another test to test the refactoring? Some of the variables can even be moved up to the class level. Should testing classes and methods follow the same rules as regular classes/methods? Here's an example: [TestMethod] public void MergeSortAssertArrayIsSorted() { int[] a = new int[1000]; Random rand = new Random(DateTime.Now.Millisecond); for(int i = 0; i < a.Length; i++) { a[i] = rand.Next(Int16.MaxValue); } int[] b = new int[1000]; a.CopyTo(b, 0); List<int> temp = b.ToList(); temp.Sort(); b = temp.ToArray(); MergeSort merge = new MergeSort(); merge.mergeSort(a, 0, a.Length - 1); CollectionAssert.AreEqual(a, b); } [TestMethod] public void InsertionSortAssertArrayIsSorted() { int[] a = new int[1000]; Random rand = new Random(DateTime.Now.Millisecond); for (int i = 0; i < a.Length; i++) { a[i] = rand.Next(Int16.MaxValue); } int[] b = new int[1000]; a.CopyTo(b, 0); List<int> temp = b.ToList(); temp.Sort(); b = temp.ToArray(); InsertionSort merge = new InsertionSort(); merge.insertionSort(a); CollectionAssert.AreEqual(a, b); }

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  • Login takes very long, annoying repaints once a minute when logged in: How to troubleshoot?

    - by user946850
    I am suffering from a strange problem with my Gnome Shell in Ubuntu 12.10. The login takes very long ( 30 sec), with a blank screen. In Google Chrome and Thunderbird (and perhaps in other applications), the main window freezes and is repainted in periodic intervals of less than one minute. The freeze takes several seconds, and it seems that font and appearance of, e.g., tabs and buttons briefly changes. Attempting to enable the second monitor show an error message related to XRANDR. Everything seems to have started three days ago, after I had to force-shutdown the machine while it was hibernating due to low power. (It was hibernating for quite a while and didn't want to stop.) Silly me. I have tried the following measures, with no avail: Checked all package file md5 hashes using debsums Reinstalled all packages using a variant of dpkg --get-selection \* | xargs apt-get install -reinstall Temporarily moved configuration directories such as .gconf, .config and .gnome2 to another location Created a new user account When I choose "Ubuntu" during login, the problems disappear. I am sort of frustrated that reinstalling all packages didn't fix the issue. How to troubleshoot this Gnome Shell (?) problem, short of reinstalling the system? (Or did anyone see this kind of behavior on their machine?)

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  • Caesar Cipher Program In C++ [migrated]

    - by xaliap81
    I am trying to write a caesar cipher program in c++. This is my codes template: int chooseKEY (){ //choose key shift from 1-26 } void encrypt (char * w, char *e, int key) { //Encryption function, *w is the text in the beginning, the *e is the encrypted text //Encryption in being made only in letters noy in numbers and punctuations // *e = *w + key } void decrypt (char * e, char *w, int key) { // Decryption function, *e is the text in the beginning, the *w is the decrypted text //Dencryption in being made only in letters no numbers and punctuations // *w = *e - key } void Caesar (char * inputFile, char * outputFile, int key, int mode) { // Read the inputfile which contains some data. If mode ==1 then the data is being //encrypted else if mode == 0 the data is being decrypted and is being written in //the output file } void main() { // call the Caesar function } The program has four functions, chooseKey function have to return an int as a shift key from 1-26. Encrypt function has three parameters, *w is the text in the beginning, *e is the encrypted text and the key is from the choosekey function.For encryption : Only letters have to be encrypted not numbers or punctuation and the letters are counting cyclic. Decrypt function has three parameters *e is the encrypted text, *w is the beginning text and the key. Caesar function has four parameters, inputfile which is the file that contains the beginning text, output file which contains the encrypted text, the key and the mode (if mode==1) encryption, (mode ==0) decryption. This is my sample code: #include <iostream> #include <fstream> using namespace std; int chooseKey() { int key_number; cout << "Give a number from 1-26: "; cin >> key_number; while(key_number<1 || key_number>26) { cout << "Your number have to be from 1-26.Retry: "; cin >> key_number; } return key_number; } void encryption(char *w, char *e, int key){ char *ptemp = w; while(*ptemp){ if(isalpha(*ptemp)){ if(*ptemp>='a'&&*ptemp<='z') { *ptemp-='a'; *ptemp+=key; *ptemp%=26; *ptemp+='A'; } } ptemp++; } w=e; } void decryption (char *e, char *w, int key){ char *ptemp = e; while(*ptemp){ if(isalpha(*ptemp)) { if(*ptemp>='A'&&*ptemp<='Z') { *ptemp-='A'; *ptemp+=26-key; *ptemp%=26; *ptemp+='a'; } } ptemp++; } e=w; } void Caesar (char *inputFile, char *outputFile, int key, int mode) { ifstream input; ofstream output; char buf, buf1; input.open(inputFile); output.open(outputFile); buf=input.get(); while(!input.eof()) { if(mode == 1){ encryption(&buf, &buf1, key); }else{ decryption(&buf1, &buf, key); } output << buf; buf=input.get(); } input.close(); output.close(); } int main(){ int key, mode; key = chooseKey(); cout << "1 or 0: "; cin >> mode; Caesar("test.txt","coded.txt",key,mode); system("pause"); } I am trying to run the code and it is being crashed (Debug Assertion Failed). I think the problem is somewhere inside Caesar function.How to call the encrypt and decrypt functions. But i don't know what exactly is. Any ideas?

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  • Long 'Wait' Time for three php/CSS files. Is something blocking them?

    - by William Pitcher
    I have been speed optimizing a Wordpress site to little effect. There are three files CSS-related php files from the Wordpress theme that are delaying page loads on the site. One of the three files is basically one line of custom CSS from the custom CSS feature in the theme. You can see what I am talking about with this Pingdom speed test: The yellow is 'Wait'. There are no slow items in the cut-off portion of the image. The full results are here: Pingdom Results Page 1. Any thoughts on what might be causing this? I understand that I have blocking CSS or JS files, but I don't see anything that would be causing that long of a wait. When I ran the P3 Plugin Profiler, Wordpress and all plugins appeared fine -- it is the theme that is taking all the time. GTmetrix recommends avoiding dynamic queries. I assume all the ver=3.61 references are to the version of Wordpress (which I am using). I noticed that my Wordpress sites using other themes don't make this query (at least not over and over). 2. Is this typical coding practice? 3. How much negative impact do these query-strings have -- a little or a lot? I tried searching for similar questions here, please excuse me if I missed something. Sometimes, I know just enough to be dangerous.

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  • Quick Replace in Visual Studio 2010 fails to use Tagged Expression n

    - by slomojo
    I'm trying to do some basic regex Quick Replace operations in Visual Studio 2010, but when I use regex grouping I don't get Tagged Expressions (ie. \1 \2 etc.) returning their values, instead they are blank. For example: Text int a = int.Parse("10"); int b = int.Parse("20"); int c = int.Parse("30"); Search Pattern (regex enabled) int\.Parse\("([0-9]*)"\); Replace \1; Replaced Text int a = ; int b = ; int c = ;

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  • Collision Detection Problems

    - by MrPlosion
    So I'm making a 2D tile based game but I can't quite get the collisions working properly. I've taken the code from the Platformer Sample and implemented it into my game as seen below. One problem I'm having is when I'm on the ground for some strange reason I can't move to the left. Now I'm pretty sure this problem is from the HandleCollisions() method because when I stop running it I can smoothly move around with no problems. Another problem I'm having is when I'm close to a tile the character jitters very strangely. I will try to post a video if necessary. Here is the HandleCollisions() method: Thanks. void HandleCollisions() { Rectangle bounds = BoundingRectangle; int topTile = (int)Math.Floor((float)bounds.Top / World.PixelTileSize); int bottomTile = (int)Math.Ceiling((float)bounds.Bottom / World.PixelTileSize) - 1; int leftTile = (int)Math.Floor((float)bounds.Left / World.PixelTileSize); int rightTile = (int)Math.Ceiling((float)bounds.Right / World.PixelTileSize) - 1; isOnGround = false; for(int x = leftTile; x <= rightTile; x++) { for(int y = topTile; y <= bottomTile; y++) { if(world.Map[y, x].Collidable == true) { Rectangle tileBounds = new Rectangle(x * World.PixelTileSize, y * World.PixelTileSize, World.PixelTileSize, World.PixelTileSize); Vector2 depth = RectangleExtensions.GetIntersectionDepth(bounds, tileBounds); if(depth != Vector2.Zero) { if(Math.Abs(depth.Y) < Math.Abs(depth.X)) { isOnGround = true; position = new Vector2(position.X, position.Y + depth.Y); } else { position = new Vector2(position.X + depth.X, position.Y); } bounds = BoundingRectangle; } } } }

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  • spliiting code in java-don't know what's wrong [closed]

    - by ???? ?????
    I'm writing a code to split a file into many files with a size specified in the code, and then it will join these parts later. The problem is with the joining code, it doesn't work and I can't figure what is wrong! This is my code: import java.io.*; import java.util.*; public class StupidSplit { static final int Chunk_Size = 10; static int size =0; public static void main(String[] args) throws IOException { String file = "b.txt"; int chunks = DivideFile(file); System.out.print((new File(file)).delete()); System.out.print(JoinFile(file, chunks)); } static boolean JoinFile(String fname, int nChunks) { /* * Joins the chunks together. Chunks have been divided using DivideFile * function so the last part of filename will ".partxxxx" Checks if all * parts are together by matching number of chunks found against * "nChunks", then joins the file otherwise throws an error. */ boolean successful = false; File currentDirectory = new File(System.getProperty("user.dir")); // File[] fileList = currentDirectory.listFiles(); /* populate only the files having extension like "partxxxx" */ List<File> lst = new ArrayList<File>(); // Arrays.sort(fileList); for (File file : fileList) { if (file.isFile()) { String fnm = file.getName(); int lastDot = fnm.lastIndexOf('.'); // add to list which match the name given by "fname" and have //"partxxxx" as extension" if (fnm.substring(0, lastDot).equalsIgnoreCase(fname) && (fnm.substring(lastDot + 1)).substring(0, 4).equals("part")) { lst.add(file); } } } /* * sort the list - it will be sorted by extension only because we have * ensured that list only contains those files that have "fname" and * "part" */ File[] files = (File[]) lst.toArray(new File[0]); Arrays.sort(files); System.out.println("size ="+files.length); System.out.println("hello"); /* Ensure that number of chunks match the length of array */ if (files.length == nChunks-1) { File ofile = new File(fname); FileOutputStream fos; FileInputStream fis; byte[] fileBytes; int bytesRead = 0; try { fos = new FileOutputStream(ofile,true); for (File file : files) { fis = new FileInputStream(file); fileBytes = new byte[(int) file.length()]; bytesRead = fis.read(fileBytes, 0, (int) file.length()); assert(bytesRead == fileBytes.length); assert(bytesRead == (int) file.length()); fos.write(fileBytes); fos.flush(); fileBytes = null; fis.close(); fis = null; } fos.close(); fos = null; } catch (FileNotFoundException fnfe) { System.out.println("Could not find file"); successful = false; return successful; } catch (IOException ioe) { System.out.println("Cannot write to disk"); successful = false; return successful; } /* ensure size of file matches the size given by server */ successful = (ofile.length() == StupidSplit.size) ? true : false; } else { successful = false; } return successful; } static int DivideFile(String fname) { File ifile = new File(fname); FileInputStream fis; String newName; FileOutputStream chunk; //int fileSize = (int) ifile.length(); double fileSize = (double) ifile.length(); //int nChunks = 0, read = 0, readLength = Chunk_Size; int nChunks = 0, read = 0, readLength = Chunk_Size; byte[] byteChunk; try { fis = new FileInputStream(ifile); StupidSplit.size = (int)ifile.length(); while (fileSize > 0) { if (fileSize <= Chunk_Size) { readLength = (int) fileSize; } byteChunk = new byte[readLength]; read = fis.read(byteChunk, 0, readLength); fileSize -= read; assert(read==byteChunk.length); nChunks++; //newName = fname + ".part" + Integer.toString(nChunks - 1); newName = String.format("%s.part%09d", fname, nChunks - 1); chunk = new FileOutputStream(new File(newName)); chunk.write(byteChunk); chunk.flush(); chunk.close(); byteChunk = null; chunk = null; } fis.close(); System.out.println(nChunks); // fis = null; } catch (FileNotFoundException fnfe) { System.out.println("Could not find the given file"); System.exit(-1); } catch (IOException ioe) { System.out .println("Error while creating file chunks. Exiting program"); System.exit(-1); }System.out.println(nChunks); return nChunks; } } }

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  • Writing a method to 'transform' an immutable object: how should I approach this?

    - by Prog
    (While this question has to do with a concrete coding dilemma, it's mostly about what's the best way to design a function.) I'm writing a method that should take two Color objects, and gradually transform the first Color into the second one, creating an animation. The method will be in a utility class. My problem is that Color is an immutable object. That means that I can't do color.setRGB or color.setBlue inside a loop in the method. What I can do, is instantiate a new Color and return it from the method. But then I won't be able to gradually change the color. So I thought of three possible solutions: 1- The client code includes the method call inside a loop. For example: int duration = 1500; // duration of the animation in milliseconds int steps = 20; // how many 'cycles' the animation will take for(int i=0; i<steps; i++) color = transformColor(color, targetColor, duration, steps); And the method would look like this: Color transformColor(Color original, Color target, int duration, int steps){ int redDiff = target.getRed() - original.getRed(); int redAddition = redDiff / steps; int newRed = original.getRed() + redAddition; // same for green and blue .. Thread.sleep(duration / STEPS); // exception handling omitted return new Color(newRed, newGreen, newBlue); } The disadvantage of this approach is that the client code has to "do part of the method's job" and include a for loop. The method doesn't do it's work entirely on it's own, which I don't like. 2- Make a mutable Color subclass with methods such as setRed, and pass objects of this class into transformColor. Then it could look something like this: void transformColor(MutableColor original, Color target, int duration){ final int STEPS = 20; int redDiff = target.getRed() - original.getRed(); int redAddition = redDiff / steps; int newRed = original.getRed() + redAddition; // same for green and blue .. for(int i=0; i<STEPS; i++){ original.setRed(original.getRed() + redAddition); // same for green and blue .. Thread.sleep(duration / STEPS); // exception handling omitted } } Then the calling code would usually look something like this: // The method will usually transform colors of JComponents JComponent someComponent = ... ; // setting the Color in JComponent to be a MutableColor Color mutableColor = new MutableColor(someComponent.getForeground()); someComponent.setForeground(mutableColor); // later, transforming the Color in the JComponent transformColor((MutableColor)someComponent.getForeground(), new Color(200,100,150), 2000); The disadvantage is - the need to create a new class MutableColor, and also the need to do casting. 3- Pass into the method the actual mutable object that holds the color. Then the method could do object.setColor or similar every iteration of the loop. Two disadvantages: A- Not so elegant. Passing in the object that holds the color just to transform the color feels unnatural. B- While most of the time this method will be used to transform colors inside JComponent objects, other kinds of objects may have colors too. So the method would need to be overloaded to receive other types, or receive Objects and have instanceof checks inside.. Not optimal. Right now I think I like solution #2 the most, than solution #1 and solution #3 the least. However I'd like to hear your opinions and suggestions regarding this.

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  • help needed on deciphering the g++ vtable dumps

    - by Ganesh Kundapur
    Hi, for the fallow class hierarchy class W { public: virtual void f() { cout << "W::f()" << endl; } virtual void g() { cout << "W::g()" << endl; } }; class AW : public virtual W { public: void g() { cout << "AW::g()" << endl; } }; class BW : public virtual W { public: void f() { cout << "BW::f()" << endl; } }; class CW : public AW, public BW { }; g++ -fdump-class-hierarchy is Vtable for W W::_ZTV1W: 4u entries 0 (int ()(...))0 4 (int ()(...))(& _ZTI1W) 8 W::f 12 W::g Class W size=4 align=4 base size=4 base align=4 W (0xb6e3da50) 0 nearly-empty vptr=((& W::_ZTV1W) + 8u) Vtable for AW AW::_ZTV2AW: 7u entries 0 0u 4 0u 8 0u 12 (int ()(...))0 16 (int ()(...))(& _ZTI2AW) 20 W::f 24 AW::g VTT for AW AW::_ZTT2AW: 2u entries 0 ((& AW::_ZTV2AW) + 20u) 4 ((& AW::_ZTV2AW) + 20u) Class AW size=4 align=4 base size=4 base align=4 AW (0xb6dbf6c0) 0 nearly-empty vptridx=0u vptr=((& AW::_ZTV2AW) + 20u) W (0xb6e3da8c) 0 nearly-empty virtual primary-for AW (0xb6dbf6c0) vptridx=4u vbaseoffset=-0x00000000000000014 Vtable for BW BW::_ZTV2BW: 7u entries 0 0u 4 0u 8 0u 12 (int ()(...))0 16 (int ()(...))(& _ZTI2BW) 20 BW::f 24 W::g VTT for BW BW::_ZTT2BW: 2u entries 0 ((& BW::_ZTV2BW) + 20u) 4 ((& BW::_ZTV2BW) + 20u) Class BW size=4 align=4 base size=4 base align=4 BW (0xb6dbf7c0) 0 nearly-empty vptridx=0u vptr=((& BW::_ZTV2BW) + 20u) W (0xb6e3dac8) 0 nearly-empty virtual primary-for BW (0xb6dbf7c0) vptridx=4u vbaseoffset=-0x00000000000000014 Vtable for CW CW::_ZTV2CW: 14u entries 0 0u 4 0u 8 4u 12 (int ()(...))0 16 (int ()(...))(& _ZTI2CW) 20 BW::_ZTv0_n12_N2BW1fEv 24 AW::g 28 4294967292u 32 4294967292u 36 0u 40 (int ()(...))-0x00000000000000004 44 (int ()(...))(& _ZTI2CW) 48 BW::f 52 0u Construction vtable for AW (0xb6dbf8c0 instance) in CW CW::_ZTC2CW0_2AW: 7u entries 0 0u 4 0u 8 0u 12 (int ()(...))0 16 (int ()(...))(& _ZTI2AW) 20 W::f 24 AW::g Construction vtable for BW (0xb6dbf900 instance) in CW CW::_ZTC2CW4_2BW: 13u entries 0 4294967292u 4 4294967292u 8 0u 12 (int ()(...))0 16 (int ()(...))(& _ZTI2BW) 20 BW::f 24 0u 28 0u 32 4u 36 (int ()(...))4 40 (int ()(...))(& _ZTI2BW) 44 BW::_ZTv0_n12_N2BW1fEv 48 W::g VTT for CW CW::_ZTT2CW: 7u entries 0 ((& CW::_ZTV2CW) + 20u) 4 ((& CW::_ZTC2CW0_2AW) + 20u) 8 ((& CW::_ZTC2CW0_2AW) + 20u) 12 ((& CW::_ZTC2CW4_2BW) + 20u) 16 ((& CW::_ZTC2CW4_2BW) + 44u) 20 ((& CW::_ZTV2CW) + 20u) 24 ((& CW::_ZTV2CW) + 48u) Class CW size=8 align=4 base size=8 base align=4 CW (0xb6bea2d0) 0 vptridx=0u vptr=((& CW::_ZTV2CW) + 20u) AW (0xb6dbf8c0) 0 nearly-empty primary-for CW (0xb6bea2d0) subvttidx=4u W (0xb6e3db04) 0 nearly-empty virtual primary-for AW (0xb6dbf8c0) vptridx=20u vbaseoffset=-0x00000000000000014 BW (0xb6dbf900) 4 nearly-empty lost-primary subvttidx=12u vptridx=24u vptr=((& CW::_ZTV2CW) + 48u) W (0xb6e3db04) alternative-path what are each entries in Vtable for AW AW::_ZTV2AW: 7u entries 0 0u // ? 4 0u // ? 8 0u // ? Vtable for CW CW::_ZTV2CW: 14u entries 0 0u // ? 4 0u // ? 8 4u // ? 12 (int ()(...))0 16 (int ()(...))(& _ZTI2CW) 20 BW::_ZTv0_n12_N2BW1fEv // ? 24 AW::g 28 4294967292u // ? 32 4294967292u // ? 36 0u // ? 40 (int ()(...))-0x00000000000000004 // some delta 44 (int ()(...))(& _ZTI2CW) 48 BW::f 52 0u // ? Thanks, Ganesh

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  • seg fault caused by malloc and sscanf in a function

    - by Framester
    Hi, I want to open a text file (see below), read the first int in every line and store it in an array, but I get an segmentation fault. I got rid of all gcc warnings, I read through several tutorials I found on the net and searched stackoverflow for solutions, but I could't make out, what I am doing wrong. It works when I have everything in the main function (see example 1), but not when I transfer it to second function (see example 2 further down). In example 2 I get, when I interpret gdb correctly a seg fault at sscanf (line,"%i",classes[i]);. I'm afraid, it could be something trivial, but I already wasted one day on it. Thanks in advance. [Example 1] Even though that works with everything in main: #include<stdio.h> #include<stdlib.h> #include<string.h> const int LENGTH = 1024; int main() { char *filename="somedatafile.txt"; int *classes; int lines; FILE *pfile = NULL; char line[LENGTH]; pfile=fopen(filename,"r"); int numlines=0; char *p; while(fgets(line,LENGTH,pfile)){ numlines++; } rewind(pfile); classes=(int *)malloc(numlines*sizeof(int)); if(classes == NULL){ printf("\nMemory error."); exit(1); } int i=0; while(fgets(line,LENGTH,pfile)){ printf("\n"); p = strtok (line," "); p = strtok (NULL, ", "); sscanf (line,"%i",&classes[i]); i++; } fclose(pfile); return 1; } [Example 2] This does not with the functionality transfered to a function: #include<stdio.h> #include<stdlib.h> #include<string.h> const int LENGTH = 1024; void read_data(int **classes,int *lines, char *filename){ FILE *pfile = NULL; char line[LENGTH]; pfile=fopen(filename,"r"); int numlines=0; char *p; while(fgets(line,LENGTH,pfile)){ numlines++; } rewind(pfile); * classes=(int *)malloc(numlines*sizeof(int)); if(*classes == NULL){ printf("\nMemory error."); exit(1); } int i=0; while(fgets(line,LENGTH,pfile)){ printf("\n"); p = strtok (line," "); p = strtok (NULL, ", "); sscanf (line,"%i",classes[i]); i++; } fclose(pfile); *lines=numlines; } int main() { char *filename="somedatafile.txt"; int *classes; int lines; read_data(&classes, &lines,filename) ; for(int i=0;i<lines;i++){ printf("\nclasses[i]=%i",classes[i]); } return 1; } [Content of somedatafile.txt] 50 21 77 0 28 0 27 48 22 2 55 0 92 0 0 26 36 92 56 4 53 0 82 0 52 -5 29 30 2 1 37 0 76 0 28 18 40 48 8 1 37 0 79 0 34 -26 43 46 2 1 85 0 88 -4 6 1 3 83 80 5 56 0 81 0 -4 11 25 86 62 4 55 -1 95 -3 54 -4 40 41 2 1 53 8 77 0 28 0 23 48 24 4 37 0 101 -7 28 0 64 73 8 1 ...

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  • Nested loops break out unexpectedly

    - by Metju
    Hi guys, I'm trying to create a sudoku game, for those that do not know what it is. You have a 9x9 box that needs to be filled with numbers from 1-9, every number must be unique in its row and column, and also in the 3x3 box it is found. I ended up doing loads of looping within a 2 dimensional array. But at some point it just stops, with no exceptions whatsoever, just breaks out and nothing happens, and it's not always at the same position, but always goes past half way. I was expecting a stack overflow exception at least. Here's my code: public class Engine { public int[,] Create() { int[,] outer = new int[9, 9]; for (int i = 0; i < 9; i++) { for (int j = 0; j < 9; j++) { outer[i, j] = GetRandom(GetUsed(outer, i, j)); } } return outer; } List<int> GetUsed(int[,] arr, int x, int y) { List<int> usedNums = new List<int>(); for (int i = 0; i < 9; i++) { if (arr[x, i] != 0 && i != y) { if(!usedNums.Contains(arr[x, i])) usedNums.Add(arr[x, i]); } } for (int i = 0; i < 9; i++) { if (arr[i, y] != 0 && i != x) { if (!usedNums.Contains(arr[i, y])) usedNums.Add(arr[i, y]); } } int x2 = 9 - (x + 1); int y2 = 9 - (y + 1); if (x2 <= 3) x2 = 2; else if (x2 > 3 && x2 <= 6) x2 = 5; else x2 = 8; if (y2 <= 3) y2 = 2; else if (y2 > 3 && y2 <= 6) y2 = 5; else y2 = 8; for (int i = x2 - 2; i < x2; i++) { for (int j = y2 - 2; j < y2; j++) { if (arr[i, j] != 0 && i != x && j != y) { if (!usedNums.Contains(arr[i, j])) usedNums.Add(arr[i, j]); } } } return usedNums; } int GetRandom(List<int> numbers) { Random r; int newNum; do { r = new Random(); newNum = r.Next(1, 10); } while (numbers.Contains(newNum)); return newNum; } }

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  • output image is not displayed

    - by gerry chocolatos
    so, im doing an image detection which i have to process on each red, green, n blue element to get the edge map and combine them become one to show the output. but it doesnt show my output image would anyone pls be kind enough to help me? here is my code so far. //get the red element process_red = new int[width * height]; counter = 0; for(int i = 0; i < 256; i++) { for(int j = 0; j < 256; j++) { int clr = buff_red.getRGB(j, i); int red = (clr & 0x00ff0000) >> 16; red = (0xFF<<24)|(red<<16)|(red<<8)|red; process_red[counter] = red; counter++; } } //set threshold value for red element int threshold = 100; for (int x = 0; x < width; x++) { for (int y = 0; y < height; y++) { int bin = (buff_red.getRGB(x, y) & 0x000000ff); if (bin < threshold) bin = 0; else bin = 255; buff_red.setRGB(x,y, 0xff000000 | bin << 16 | bin << 8 | bin); } } and i do the same way for my green n blue elements. and then i wanted to get to combination of the three by doing it this way: //combine the three elements process_combine = new int[width * height]; counter = 0; for(int i = 0; i < 256; i++) { for(int j = 0; j < 256; j++) { int clr_a = buff_red.getRGB(j, i); int ar = clr_a & 0x000000ff; int clr_b = buff_green.getRGB(j, i); int bg = clr_b & 0x000000ff; int clr_c = buff_blue.getRGB(j, i); int cb = clr_b & 0x000000ff; int alpha = 0xff000000; int combine = alpha|(ar<<16)|(bg<<8)|cb; process_combine[counter] = combine; counter++; } } buff_rgb = new BufferedImage(width,height, BufferedImage.TYPE_INT_ARGB); Graphics rgb; rgb = buff_rgb.getGraphics(); rgb.drawImage(output_rgb, 0, 0, null); rgb.dispose(); repaint(); and to show the output whic is from the combining process, i use a draw method: g.drawImage(buff_rgb,800,100,this); but still it doesnt show the image. can anyone pls help me? ur help is really appreciated. thanks.

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