Buffer Overrun problem - GameCreators Forum

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archie456

16

Years of Service

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Joined: 13th Feb 2008

Location:

Posted: 2nd Mar 2008 21:22

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Hi,

I've written a small program which animates a sprite on the screen and moves it around with the arrow keys.

All works fine, apart from when I exit (i.e. click the close icon) Visual C++ 2008 Express Edition given an error "A buffer overrun has occurred which has corrpted the program's internal state..."

In the main LoopGDK I have two IF statements which collect keyboard input thus:

if (dbRightKey () == 1)

if (dbLeftKey () == 1)

Any ideas why I'm getting this error?

// whenever using Dark GDK you must ensure you include the header file
#include "DarkGDK.h"
#include <stdlib.h>

// the main entry point for the application is this function
void DarkGDK ( void )
{

int mousemovex = 0;
	int mousemovey = 0;
	int headposx = 200;
	int headposy = 400;
	int headframe = 5;
	int headpass = 0;
	int headlimit = 5;
	char message[100];

// turn on sync rate and set maximum rate to 60 fps
	dbSyncOn   ( );
	dbSyncRate ( 60 );
	dbSetDisplayMode ( 1280 , 1025 , 32 );
	dbMaximizeWindow ( );

dbLoadImage ( "Head Roll Build.png", 8 );
	dbCreateAnimatedSprite ( 8, "Head Roll Build.png", 5, 5, 8 );
	dbSprite ( 8, headposx, headposy, 8 );

// our main loop
	while ( LoopGDK ( ) )
	{

if (dbRightKey () == 1)
		{
			headposx = headposx + 10;
			headpass--;
			if (headpass < 0) 
			{
				headframe = headframe - 1; 
				headpass = headlimit;
			}
			if (headframe ==  6) (headframe = 1);
			else if (headframe == 11) (headframe = 6);
			else if (headframe == 16) (headframe = 11);
			else if (headframe == 21) (headframe = 16);
			else if (headframe == 26) (headframe = 21);
		}

if (dbLeftKey () == 1)
		{
			headposx = headposx + 10;
			headpass++;
			if (headpass > headlimit) 
			{
				headframe = headframe - 1; 
				headpass = 0;
			}
			if (headframe ==  0) {(headframe = 5);dbText(0, 0, "kick 1");}
			else if (headframe == 5) {(headframe = 10);dbText(0, 0, "kick 2");}
			else if (headframe == 10) {(headframe = 15);dbText(0, 0, "kick 3");}
			else if (headframe == 15) {(headframe = 20);dbText(0, 0, "kick 4");}
			else if (headframe == 20) {(headframe = 25);dbText(0, 0, "kick 5");}
		}

if (dbDownKey () == 1)
		{
			headposy = headposy + 10;
		}

if (dbUpKey () == 1)
		{
			headposy = headposy - 10;
		}

dbSetSpriteFrame ( 8 , headframe );
		dbSprite ( 8, headposx, headposy, 8 );

itoa(headframe, message,10);
		dbText(0, 0, message);

// update the screen
		dbSync ( );
	}

// return back to windows
	return;
}

+ Code Snippet

// whenever using Dark GDK you must ensure you include the header file
#include "DarkGDK.h"
#include <stdlib.h>

// the main entry point for the application is this function
void DarkGDK ( void )
{

	int mousemovex = 0;
	int mousemovey = 0;
	int headposx = 200;
	int headposy = 400;
	int headframe = 5;
	int headpass = 0;
	int headlimit = 5;
	char message[100];


	// turn on sync rate and set maximum rate to 60 fps
	dbSyncOn   ( );
	dbSyncRate ( 60 );
	dbSetDisplayMode ( 1280 , 1025 , 32 );
	dbMaximizeWindow ( );

	dbLoadImage ( "Head Roll Build.png", 8 );
	dbCreateAnimatedSprite ( 8, "Head Roll Build.png", 5, 5, 8 );
	dbSprite ( 8, headposx, headposy, 8 );

	// our main loop
	while ( LoopGDK ( ) )
	{




		if (dbRightKey () == 1)
		{
			headposx = headposx + 10;
			headpass--;
			if (headpass < 0) 
			{
				headframe = headframe - 1; 
				headpass = headlimit;
			}
			if (headframe ==  6) (headframe = 1);
			else if (headframe == 11) (headframe = 6);
			else if (headframe == 16) (headframe = 11);
			else if (headframe == 21) (headframe = 16);
			else if (headframe == 26) (headframe = 21);
		}

		if (dbLeftKey () == 1)
		{
			headposx = headposx + 10;
			headpass++;
			if (headpass > headlimit) 
			{
				headframe = headframe - 1; 
				headpass = 0;
			}
			if (headframe ==  0) {(headframe = 5);dbText(0, 0, "kick 1");}
			else if (headframe == 5) {(headframe = 10);dbText(0, 0, "kick 2");}
			else if (headframe == 10) {(headframe = 15);dbText(0, 0, "kick 3");}
			else if (headframe == 15) {(headframe = 20);dbText(0, 0, "kick 4");}
			else if (headframe == 20) {(headframe = 25);dbText(0, 0, "kick 5");}
		}

		if (dbDownKey () == 1)
		{
			headposy = headposy + 10;
		}

		if (dbUpKey () == 1)
		{
			headposy = headposy - 10;
		}


		dbSetSpriteFrame ( 8 , headframe );
		dbSprite ( 8, headposx, headposy, 8 );

		itoa(headframe, message,10);
		dbText(0, 0, message);

		// update the screen
		dbSync ( );
	}

	// return back to windows
	return;
}

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Niels Henriksen

20

Years of Service

User Offline

Joined: 27th Sep 2004

Location: Behind you breathing heavely

Posted: 2nd Mar 2008 23:21

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the problem is here dbText(0, 0, message);

you need to empty message every time its shown. I can see that you only give space for 100 char.

Been there

Niels Henriksen
Working on a (MMO)RPG right now in LightEngine (thanks kBessa)

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Benjamin

21

Years of Service

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Joined: 24th Nov 2002

Location: France

Posted: 3rd Mar 2008 09:55

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I don't see any problem there, but I'd suggest you replace itoa with a standard C++ function, perhaps sprintf:

+ Code Snippet

sprintf(message, "%i", headframe);

Multisync - TCP Server/Client Multiplayer Plugin (DBP/DBCe)

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archie456

16

Years of Service

User Offline

Joined: 13th Feb 2008

Location:

Posted: 3rd Mar 2008 22:24

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Thanks for the replies;
I think that Niels is correct as when I comment out the message display part I don't get the error.

What do you mean by empty the message everytime? Do you mean;

delete message;

or

message[]="";

by the way message[]=""; states error c2059; syntax error: ']'.

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jason p sage

17

Years of Service

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Joined: 10th Jun 2007

Location: Ellington, CT USA

Posted: 4th Mar 2008 18:18 Edited at: 4th Mar 2008 18:19

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hmmm... I think you need a class like this one I'm posting or learn about dynamic memory, static char buffers, and the string lib or something.

My Class is a home brew string class whos advantage is in its simplicity. Correct? Many will say Bad Form! Does it Work? Yup. Easy? Yup. Lean? YUP... Perfect? Well.. doesn't crash unless you mess up terribly. Its been working for in MILES and MILES of code.

jfc_string.h

/*============================================================================
|    _________ _______  _______  ______  _______    Jegas, LLC               |
|   /___  ___// _____/ / _____/ / __  / / _____/    JasonPSage@jegas.com     |
|      / /   / /__    / / ___  / /_/ / / /____                               |
|     / /   / ____/  / / /  / / __  / /____  /                               |
|____/ /   / /___   / /__/ / / / / / _____/ /                                |
/_____/   /______/ /______/ /_/ /_/ /______/                                 |
|                 Under the Hood                                             |
==============================================================================
           Copyright(c)2008 Jegas, LLC                      
============================================================================*/
#pragma once
//=============================================================================
class JFC_STRING{
//=============================================================================
public:  
  char *s;char chNull;
  unsigned int uiLength;
  JFC_STRING();
  ~JFC_STRING();
  void Clear(void);
  void Clear(int p_NewLength);// allows making a buffer instantly.
  void ConCat(const char *p_char);
  void Set(const char *p_char);
  char *Get(void);
  unsigned int Length(void);
  bool EqualCS(char *p_szCompareThis); // Case Sensitive
  bool Equal(char *p_szCompareThis);
  //function Replace(source$,search$,key$)
  //Function Misc_strip_path(f$)
  //Function Remove_End(f$)
  //function strInstr(source$,search$)

};
//=============================================================================

+ Code Snippet

/*============================================================================
|    _________ _______  _______  ______  _______    Jegas, LLC               |
|   /___  ___// _____/ / _____/ / __  / / _____/    JasonPSage@jegas.com     |
|      / /   / /__    / / ___  / /_/ / / /____                               |
|     / /   / ____/  / / /  / / __  / /____  /                               |
|____/ /   / /___   / /__/ / / / / / _____/ /                                |
/_____/   /______/ /______/ /_/ /_/ /______/                                 |
|                 Under the Hood                                             |
==============================================================================
           Copyright(c)2008 Jegas, LLC                      
============================================================================*/
#pragma once
//=============================================================================
class JFC_STRING{
//=============================================================================
public:  
  char *s;char chNull;
  unsigned int uiLength;
  JFC_STRING();
  ~JFC_STRING();
  void Clear(void);
  void Clear(int p_NewLength);// allows making a buffer instantly.
  void ConCat(const char *p_char);
  void Set(const char *p_char);
  char *Get(void);
  unsigned int Length(void);
  bool EqualCS(char *p_szCompareThis); // Case Sensitive
  bool Equal(char *p_szCompareThis);
  //function Replace(source$,search$,key$)
  //Function Misc_strip_path(f$)
  //Function Remove_End(f$)
  //function strInstr(source$,search$)

};
//=============================================================================

jfc_string.cpp

/*============================================================================
|    _________ _______  _______  ______  _______    Jegas, LLC               |
|   /___  ___// _____/ / _____/ / __  / / _____/    JasonPSage@jegas.com     |
|      / /   / /__    / / ___  / /_/ / / /____                               |
|     / /   / ____/  / / /  / / __  / /____  /                               |
|____/ /   / /___   / /__/ / / / / / _____/ /                                |
/_____/   /______/ /______/ /_/ /_/ /______/                                 |
|                 Under the Hood                                             |
==============================================================================
           Copyright(c)2008 Jegas, LLC                      
============================================================================*/
#include "jfc_string.h"
#include "string.h"

//=============================================================================
JFC_STRING::JFC_STRING(){
//=============================================================================
  this->s=0;
  chNull='';
  this->Clear();
};
//=============================================================================

//=============================================================================
JFC_STRING::~JFC_STRING(){
//=============================================================================
  if(this->s!=0){    
    delete this->s;
  };
};
//=============================================================================

//=============================================================================
void JFC_STRING::Clear(void){
//=============================================================================
  if(this->s!=0){
    delete this->s;
  };
  this->uiLength=0;
  this->s=new char[this->uiLength+1];
  this->s[this->uiLength]='';
};
//=============================================================================

//=============================================================================
void JFC_STRING::Clear(int p_NewLength){
//=============================================================================
  if(this->s!=0){
    delete this->s;
  };
  this->uiLength=p_NewLength;
  this->s=new char[this->uiLength+1];
  this->s[this->uiLength]='';
  int i;
  for(i=0;i<this->uiLength;i++){
    this->s[i]='';
  };
};
//=============================================================================

//=============================================================================
void JFC_STRING::ConCat(const char *p_char){
//=============================================================================
  char *st;
  this->uiLength=(unsigned int)(strlen(p_char)+this->uiLength);
  st=new char[this->uiLength+1];
  st[0]=chNull;
  strcat(st,this->s);
  strcat(st,p_char);
  delete this->s;
  this->s=new char[this->uiLength+1];
  strcpy(this->s,st);
  delete st;
  this->s[this->uiLength]='';
};
//=============================================================================

//=============================================================================
void JFC_STRING::Set(const char *p_char){
//=============================================================================
  this->Clear();
  this->ConCat(p_char);
};
//=============================================================================

//=============================================================================
char *JFC_STRING::Get(void){
//=============================================================================
  if(this->s!=0){
    return this->s;
  }else{
    return 0;
  };
};
//=============================================================================

//=============================================================================
unsigned int JFC_STRING::Length(void){
//=============================================================================
  return this->uiLength;
};
//=============================================================================

//=============================================================================
bool JFC_STRING::EqualCS(char *p_szCompareThis){
//=============================================================================
  return (strcmp(this->s,p_szCompareThis)==0); 
};
//=============================================================================

//=============================================================================
bool JFC_STRING::Equal(char *p_szCompareThis){
//=============================================================================
  return (strcmpi(this->s,p_szCompareThis)==0); 
};
//=============================================================================

+ Code Snippet

/*============================================================================
|    _________ _______  _______  ______  _______    Jegas, LLC               |
|   /___  ___// _____/ / _____/ / __  / / _____/    JasonPSage@jegas.com     |
|      / /   / /__    / / ___  / /_/ / / /____                               |
|     / /   / ____/  / / /  / / __  / /____  /                               |
|____/ /   / /___   / /__/ / / / / / _____/ /                                |
/_____/   /______/ /______/ /_/ /_/ /______/                                 |
|                 Under the Hood                                             |
==============================================================================
           Copyright(c)2008 Jegas, LLC                      
============================================================================*/
#include "jfc_string.h"
#include "string.h"




//=============================================================================
JFC_STRING::JFC_STRING(){
//=============================================================================
  this->s=0;
  chNull='';
  this->Clear();
};
//=============================================================================


//=============================================================================
JFC_STRING::~JFC_STRING(){
//=============================================================================
  if(this->s!=0){    
    delete this->s;
  };
};
//=============================================================================

//=============================================================================
void JFC_STRING::Clear(void){
//=============================================================================
  if(this->s!=0){
    delete this->s;
  };
  this->uiLength=0;
  this->s=new char[this->uiLength+1];
  this->s[this->uiLength]='';
};
//=============================================================================

//=============================================================================
void JFC_STRING::Clear(int p_NewLength){
//=============================================================================
  if(this->s!=0){
    delete this->s;
  };
  this->uiLength=p_NewLength;
  this->s=new char[this->uiLength+1];
  this->s[this->uiLength]='';
  int i;
  for(i=0;i<this->uiLength;i++){
    this->s[i]='';
  };
};
//=============================================================================



//=============================================================================
void JFC_STRING::ConCat(const char *p_char){
//=============================================================================
  char *st;
  this->uiLength=(unsigned int)(strlen(p_char)+this->uiLength);
  st=new char[this->uiLength+1];
  st[0]=chNull;
  strcat(st,this->s);
  strcat(st,p_char);
  delete this->s;
  this->s=new char[this->uiLength+1];
  strcpy(this->s,st);
  delete st;
  this->s[this->uiLength]='';
};
//=============================================================================

//=============================================================================
void JFC_STRING::Set(const char *p_char){
//=============================================================================
  this->Clear();
  this->ConCat(p_char);
};
//=============================================================================

//=============================================================================
char *JFC_STRING::Get(void){
//=============================================================================
  if(this->s!=0){
    return this->s;
  }else{
    return 0;
  };
};
//=============================================================================

//=============================================================================
unsigned int JFC_STRING::Length(void){
//=============================================================================
  return this->uiLength;
};
//=============================================================================



//=============================================================================
bool JFC_STRING::EqualCS(char *p_szCompareThis){
//=============================================================================
  return (strcmp(this->s,p_szCompareThis)==0); 
};
//=============================================================================

//=============================================================================
bool JFC_STRING::Equal(char *p_szCompareThis){
//=============================================================================
  return (strcmpi(this->s,p_szCompareThis)==0); 
};
//=============================================================================

Then you can do something like this:

+ Code Snippet

JFC_STRING *t=new JFC_STRING();
t->Set("Hello Mom");
t->ConCat(" I Love You");
dbPrint(t->Get());  // dbPrint(t->s()); would work too.

There isn't a lot of things in that class so its to learn and I find I USUALLY don't need more than the basics in game dev.

And if you take these two files and include them...
jfc_common.h

/*============================================================================
|    _________ _______  _______  ______  _______    Jegas, LLC               |
|   /___  ___// _____/ / _____/ / __  / / _____/    JasonPSage@jegas.com     |
|      / /   / /__    / / ___  / /_/ / / /____                               |
|     / /   / ____/  / / /  / / __  / /____  /                               |
|____/ /   / /___   / /__/ / / / / / _____/ /                                |
/_____/   /______/ /______/ /_/ /_/ /______/                                 |
|                 Under the Hood                                             |
==============================================================================
           Copyright(c)2008 Jegas, LLC                      
============================================================================*/
#pragma once
//============================================================================

//============================================================================
namespace JFC{
//============================================================================
  extern char CHAR1K[1024];
  extern float Interpolate(float x0, float x1, float x , float y0, float y1);
  
};
//============================================================================

+ Code Snippet

/*============================================================================
|    _________ _______  _______  ______  _______    Jegas, LLC               |
|   /___  ___// _____/ / _____/ / __  / / _____/    JasonPSage@jegas.com     |
|      / /   / /__    / / ___  / /_/ / / /____                               |
|     / /   / ____/  / / /  / / __  / /____  /                               |
|____/ /   / /___   / /__/ / / / / / _____/ /                                |
/_____/   /______/ /______/ /_/ /_/ /______/                                 |
|                 Under the Hood                                             |
==============================================================================
           Copyright(c)2008 Jegas, LLC                      
============================================================================*/
#pragma once
//============================================================================

//============================================================================
namespace JFC{
//============================================================================
  extern char CHAR1K[1024];
  extern float Interpolate(float x0, float x1, float x , float y0, float y1);
  
};
//============================================================================

jfc_common.cpp

/*============================================================================
|    _________ _______  _______  ______  _______    Jegas, LLC               |
|   /___  ___// _____/ / _____/ / __  / / _____/    JasonPSage@jegas.com     |
|      / /   / /__    / / ___  / /_/ / / /____                               |
|     / /   / ____/  / / /  / / __  / /____  /                               |
|____/ /   / /___   / /__/ / / / / / _____/ /                                |
/_____/   /______/ /______/ /_/ /_/ /______/                                 |
|                 Under the Hood                                             |
==============================================================================
           Copyright(c)2008 Jegas, LLC                      
============================================================================*/
#include "jfc_common.h"
//============================================================================
// begin                                   JFC_COMMON
//============================================================================
namespace JFC{
  char CHAR1K[1024];
  float Interpolate(float x0, float x1, float x , float y0, float y1);
};
//============================================================================

//============================================================================
// This Function Interpolates Linear Data to find to numerically
// "Guess" what the missing data is.
// The Formula Semantics are to Find "X", but by swapping the parameters
// you can find Your own "Y" just as easily.
float JFC::Interpolate(float x0, float x1, float x , float y0, float y1){
//============================================================================
  return y0+((x-x0)*((y1-y0)/(x1-x0)));
};
//============================================================================

//============================================================================
// end                                     JFC_COMMON
//============================================================================

+ Code Snippet

/*============================================================================
|    _________ _______  _______  ______  _______    Jegas, LLC               |
|   /___  ___// _____/ / _____/ / __  / / _____/    JasonPSage@jegas.com     |
|      / /   / /__    / / ___  / /_/ / / /____                               |
|     / /   / ____/  / / /  / / __  / /____  /                               |
|____/ /   / /___   / /__/ / / / / / _____/ /                                |
/_____/   /______/ /______/ /_/ /_/ /______/                                 |
|                 Under the Hood                                             |
==============================================================================
           Copyright(c)2008 Jegas, LLC                      
============================================================================*/
#include "jfc_common.h"
//============================================================================
// begin                                   JFC_COMMON
//============================================================================
namespace JFC{
  char CHAR1K[1024];
  float Interpolate(float x0, float x1, float x , float y0, float y1);
};
//============================================================================


//============================================================================
// This Function Interpolates Linear Data to find to numerically
// "Guess" what the missing data is.
// The Formula Semantics are to Find "X", but by swapping the parameters
// you can find Your own "Y" just as easily.
float JFC::Interpolate(float x0, float x1, float x , float y0, float y1){
//============================================================================
  return y0+((x-x0)*((y1-y0)/(x1-x0)));
};
//============================================================================



//============================================================================
// end                                     JFC_COMMON
//============================================================================

(Aside from a global interpolate routine you don't need now) you'll have a GLOBAL 1024 byte buffer you can use in your code anywhere. Example:

+ Code Snippet

sprintf(JFC::CHAR1K, "This is a String...Um an Integer here:%i",iMyInt);
dbPrint(JFC::CHAR1K);

[edit] Fixed filenames and some typos I had in bold... [/edit]

http://www.jasonpetersage.com/?PAGE=ironinfantry&SECTION=ironinfantry

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Dark GDK / Buffer Overrun problem