Storing bytes of an integer in a character array

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Michael P

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Joined: 6th Mar 2006

Location: London (UK)

Posted: 1st Jul 2008 18:09

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I am trying to store the individual bytes of an integer in a character array and then take the bytes that are in the character array and put them back into a new integer.

The reason for this is that in networking (using winsock), data is sent in char form. Obviously, I could just convert the integer to character form so that each number is one character e.g. 5124 would appear as C0 = 5, C1 = 1, C2 = 2, C3 = 4; C representing character and each number representing the element. The problem with this is that large numbers fill more space than is necessary; storing the actual bytes of an integer would always store 4 bytes regardless of the size of the number.

Here is my first attempt which should demonstrate what I'm attempting to do. There are several problems with this; firstly, large numbers appear wrong and secondly on exit the following run time error occurs "Stack around the variable 'iIntReturn' was corrupted". I'm not sure what I'm doing wrong, or if I'm going about this the right way:

+ Code Snippet

#include <windows.h>
#include <iostream>

using namespace std;

int main ()
{
	// Create integer and find its size.
	int iInt;
	cout << "Enter a number to transfer: ";
	cin >> iInt;

	// Save the size of an integer.
	int iSize = sizeof(iInt);

	// Create character sequence.
	char * cBuffer = new char[iSize];
	ZeroMemory(cBuffer,iSize);

	// Fill character sequence with bytes from integer.
	for(int n = 0;n<iSize;n++)
	{
		cBuffer[n] = *(&iInt+n);
	}

	// Create another integer.
	int iIntReturn;

	// Fill integer with bytes from character sequence.
	for(int n = 0;n<iSize; n++)
	{
		*(&iIntReturn+n) = cBuffer[n];
	}

	// Display second integer and wait for input.
	cout << "Second integer: " << iIntReturn << ".\n";
	int Blank;
	cin >> Blank;
	
	// Delete dynamic memory and exit.
	delete[] cBuffer;

	return(0);
}

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Benjamin

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Posted: 1st Jul 2008 18:13 Edited at: 1st Jul 2008 18:13

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+ Code Snippet

*(int*)&buffer[position] = myInt;
myInt = *(int*)&buffer[position];

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jason p sage

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Posted: 1st Jul 2008 18:19

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That is a great solution - and here is a similiarly useful construct example I use for RGBA colors. Notice the UNION in the header.

In short - You can make "two structures" point to the same place in memory like Benjamin did, and access any and each part individually. Note that the compiler throws warnings but union structs have been in existance since (bell labs, AT&T) wrote the first c compiler.

jfc_rgba.h

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

//----------------------------------------------------------------------------
// RGBA - Usage:    uRGBA MyColor;  MyColor.Red=100; MyColor.Pixel=(a dword)
//----------------------------------------------------------------------------
typedef union RGBA {
  struct {
    unsigned char Blue;
    unsigned char Green;
    unsigned char Red;
    unsigned char Alpha;
  };
  DWORD Pixel;
} uRGBA;
//----------------------------------------------------------------------------

//============================================================================
// Begin                         JFC_RGBA
//============================================================================
class JFC_RGBA{
  private:
    void Init(void);
  public:
    JFC_RGBA();
    JFC_RGBA(DWORD p_RGBA);
    JFC_RGBA(unsigned char p_Red,unsigned char p_Green, unsigned char p_Blue, unsigned char p_Alpha );
    JFC_RGBA(unsigned char p_Red,unsigned char p_Green, unsigned char p_Blue);
    
    ~JFC_RGBA();

uRGBA *RGBA;
    void Red_Set(unsigned char p_Red);
    void Green_Set(unsigned char p_Green);
    void Blue_Set(unsigned char p_Blue);
    void Alpha_Set(unsigned char p_Alpha);
    void RGB_Set(unsigned char p_Red, unsigned char p_Green, unsigned char p_Blue);
    void RGB_Set(DWORD p_RGB);
    void RGBA_Set(unsigned char p_Red, unsigned char p_Green, unsigned char p_Blue, unsigned char p_Alpha);
    void RGBA_Set(DWORD p_RGBA);
    unsigned int Red_Get(void);
    unsigned int Green_Get(void);
    unsigned int Blue_Get(void);
    unsigned int Alpha_Get(void);
    DWORD RGB_Get(void);
    DWORD RGBA_Get(void);
};
//============================================================================
// End                         JFC_RGBA
//============================================================================

+ Code Snippet

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


//----------------------------------------------------------------------------
// RGBA - Usage:    uRGBA MyColor;  MyColor.Red=100; MyColor.Pixel=(a dword)
//----------------------------------------------------------------------------
typedef union RGBA {
  struct {
    unsigned char Blue;
    unsigned char Green;
    unsigned char Red;
    unsigned char Alpha;
  };
  DWORD Pixel;
} uRGBA;
//----------------------------------------------------------------------------

//============================================================================
// Begin                         JFC_RGBA
//============================================================================
class JFC_RGBA{
  private:
    void Init(void);
  public:
    JFC_RGBA();
    JFC_RGBA(DWORD p_RGBA);
    JFC_RGBA(unsigned char p_Red,unsigned char p_Green, unsigned char p_Blue, unsigned char p_Alpha );
    JFC_RGBA(unsigned char p_Red,unsigned char p_Green, unsigned char p_Blue);
    
    ~JFC_RGBA();

    uRGBA *RGBA;
    void Red_Set(unsigned char p_Red);
    void Green_Set(unsigned char p_Green);
    void Blue_Set(unsigned char p_Blue);
    void Alpha_Set(unsigned char p_Alpha);
    void RGB_Set(unsigned char p_Red, unsigned char p_Green, unsigned char p_Blue);
    void RGB_Set(DWORD p_RGB);
    void RGBA_Set(unsigned char p_Red, unsigned char p_Green, unsigned char p_Blue, unsigned char p_Alpha);
    void RGBA_Set(DWORD p_RGBA);
    unsigned int Red_Get(void);
    unsigned int Green_Get(void);
    unsigned int Blue_Get(void);
    unsigned int Alpha_Get(void);
    DWORD RGB_Get(void);
    DWORD RGBA_Get(void);
};
//============================================================================
// End                         JFC_RGBA
//============================================================================

jfc_rgba.cpp

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

//============================================================================
// begin                                   JFC_RGB
//============================================================================
//----------------------------------------------------------------------------
void JFC_RGBA::Init(void){
//----------------------------------------------------------------------------
  this->RGBA = new uRGBA();
};
//----------------------------------------------------------------------------

//----------------------------------------------------------------------------
JFC_RGBA::JFC_RGBA(){
//----------------------------------------------------------------------------
  this->Init();
  RGBA->Pixel=0;
};
//----------------------------------------------------------------------------

//----------------------------------------------------------------------------
JFC_RGBA::JFC_RGBA(DWORD p_RGBA){
//----------------------------------------------------------------------------
  this->Init();
  this->RGBA_Set(p_RGBA); 
};
//----------------------------------------------------------------------------

//----------------------------------------------------------------------------
JFC_RGBA::JFC_RGBA(
  unsigned char p_Red,
  unsigned char p_Green, 
  unsigned char p_Blue, 
  unsigned char p_Alpha 
){
//----------------------------------------------------------------------------
  this->Init();
  this->RGBA_Set(p_Red, p_Green,p_Blue, p_Alpha);
};
//----------------------------------------------------------------------------

//----------------------------------------------------------------------------
JFC_RGBA::JFC_RGBA(
  unsigned char p_Red,
  unsigned char p_Green, 
  unsigned char p_Blue
){
//----------------------------------------------------------------------------
  this->Init();
  this->RGBA_Set(p_Red, p_Green,p_Blue,(unsigned char)255);
};
//----------------------------------------------------------------------------

//----------------------------------------------------------------------------
JFC_RGBA::~JFC_RGBA(){
//----------------------------------------------------------------------------
  delete RGBA;
};
//----------------------------------------------------------------------------

//----------------------------------------------------------------------------
void JFC_RGBA::Red_Set(unsigned char p_Red){
//----------------------------------------------------------------------------
  this->RGBA->Red=p_Red;  
};
//----------------------------------------------------------------------------

//----------------------------------------------------------------------------
void JFC_RGBA::Green_Set(unsigned char p_Green){
//----------------------------------------------------------------------------
  this->RGBA->Green=p_Green;  
};
//----------------------------------------------------------------------------

//----------------------------------------------------------------------------
void JFC_RGBA::Blue_Set(unsigned char p_Blue){
//----------------------------------------------------------------------------
  this->RGBA->Blue=p_Blue;  
};
//----------------------------------------------------------------------------

//----------------------------------------------------------------------------
void JFC_RGBA::Alpha_Set(unsigned char p_Alpha){
//----------------------------------------------------------------------------
  this->RGBA->Alpha=p_Alpha;  
};
//----------------------------------------------------------------------------

//----------------------------------------------------------------------------
void JFC_RGBA::RGB_Set(
  unsigned char p_Red, 
  unsigned char p_Green, 
  unsigned char p_Blue
){
//----------------------------------------------------------------------------
  this->RGBA->Red=p_Red;  
  this->RGBA->Green=p_Green;  
  this->RGBA->Blue=p_Blue;  
};
//----------------------------------------------------------------------------

//----------------------------------------------------------------------------
void JFC_RGBA::RGB_Set(DWORD p_RGB){
//----------------------------------------------------------------------------
  uRGBA Temp;
  Temp.Pixel=p_RGB; 
  Temp.Alpha=this->RGBA->Alpha;
  this->RGBA->Pixel=Temp.Pixel;   
};
//----------------------------------------------------------------------------

//----------------------------------------------------------------------------
void JFC_RGBA::RGBA_Set(
  unsigned char p_Red, 
  unsigned char p_Green, 
  unsigned char p_Blue, 
  unsigned char p_Alpha
){
//----------------------------------------------------------------------------
  this->RGBA->Red=p_Red;
  this->RGBA->Green=p_Green;  
  this->RGBA->Blue=p_Blue;  
  this->RGBA->Alpha=p_Alpha;  
};
//----------------------------------------------------------------------------

//----------------------------------------------------------------------------
void JFC_RGBA::RGBA_Set(DWORD p_RGBA){
//----------------------------------------------------------------------------
  this->RGBA->Pixel=p_RGBA;
};
//----------------------------------------------------------------------------

//----------------------------------------------------------------------------
unsigned int JFC_RGBA::Red_Get(void){
//----------------------------------------------------------------------------
  return this->RGBA->Red;  
};
//----------------------------------------------------------------------------

//----------------------------------------------------------------------------
unsigned int JFC_RGBA::Green_Get(void){
//----------------------------------------------------------------------------
  return this->RGBA->Green;  
};
//----------------------------------------------------------------------------

//----------------------------------------------------------------------------
unsigned int JFC_RGBA::Blue_Get(void){
//----------------------------------------------------------------------------
  return this->RGBA->Blue;  
};
//----------------------------------------------------------------------------

//----------------------------------------------------------------------------
unsigned int JFC_RGBA::Alpha_Get(void){
//----------------------------------------------------------------------------
  return this->RGBA->Alpha;  
};
//----------------------------------------------------------------------------

//----------------------------------------------------------------------------
DWORD JFC_RGBA::RGB_Get(void){
//----------------------------------------------------------------------------
  uRGBA Temp;
  Temp.Pixel = this->RGBA->Pixel;
  Temp.Alpha=0;
  return Temp.Pixel;   
};
//----------------------------------------------------------------------------

//----------------------------------------------------------------------------
DWORD JFC_RGBA::RGBA_Get(void){
//----------------------------------------------------------------------------
  return this->RGBA->Pixel;  
};
//----------------------------------------------------------------------------

//============================================================================
// end                                   JFC_RGB
//============================================================================

+ Code Snippet

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


//============================================================================
// begin                                   JFC_RGB
//============================================================================
//----------------------------------------------------------------------------
void JFC_RGBA::Init(void){
//----------------------------------------------------------------------------
  this->RGBA = new uRGBA();
};
//----------------------------------------------------------------------------

//----------------------------------------------------------------------------
JFC_RGBA::JFC_RGBA(){
//----------------------------------------------------------------------------
  this->Init();
  RGBA->Pixel=0;
};
//----------------------------------------------------------------------------

//----------------------------------------------------------------------------
JFC_RGBA::JFC_RGBA(DWORD p_RGBA){
//----------------------------------------------------------------------------
  this->Init();
  this->RGBA_Set(p_RGBA); 
};
//----------------------------------------------------------------------------

//----------------------------------------------------------------------------
JFC_RGBA::JFC_RGBA(
  unsigned char p_Red,
  unsigned char p_Green, 
  unsigned char p_Blue, 
  unsigned char p_Alpha 
){
//----------------------------------------------------------------------------
  this->Init();
  this->RGBA_Set(p_Red, p_Green,p_Blue, p_Alpha);
};
//----------------------------------------------------------------------------

//----------------------------------------------------------------------------
JFC_RGBA::JFC_RGBA(
  unsigned char p_Red,
  unsigned char p_Green, 
  unsigned char p_Blue
){
//----------------------------------------------------------------------------
  this->Init();
  this->RGBA_Set(p_Red, p_Green,p_Blue,(unsigned char)255);
};
//----------------------------------------------------------------------------


//----------------------------------------------------------------------------
JFC_RGBA::~JFC_RGBA(){
//----------------------------------------------------------------------------
  delete RGBA;
};
//----------------------------------------------------------------------------

//----------------------------------------------------------------------------
void JFC_RGBA::Red_Set(unsigned char p_Red){
//----------------------------------------------------------------------------
  this->RGBA->Red=p_Red;  
};
//----------------------------------------------------------------------------

//----------------------------------------------------------------------------
void JFC_RGBA::Green_Set(unsigned char p_Green){
//----------------------------------------------------------------------------
  this->RGBA->Green=p_Green;  
};
//----------------------------------------------------------------------------

//----------------------------------------------------------------------------
void JFC_RGBA::Blue_Set(unsigned char p_Blue){
//----------------------------------------------------------------------------
  this->RGBA->Blue=p_Blue;  
};
//----------------------------------------------------------------------------

//----------------------------------------------------------------------------
void JFC_RGBA::Alpha_Set(unsigned char p_Alpha){
//----------------------------------------------------------------------------
  this->RGBA->Alpha=p_Alpha;  
};
//----------------------------------------------------------------------------

//----------------------------------------------------------------------------
void JFC_RGBA::RGB_Set(
  unsigned char p_Red, 
  unsigned char p_Green, 
  unsigned char p_Blue
){
//----------------------------------------------------------------------------
  this->RGBA->Red=p_Red;  
  this->RGBA->Green=p_Green;  
  this->RGBA->Blue=p_Blue;  
};
//----------------------------------------------------------------------------

//----------------------------------------------------------------------------
void JFC_RGBA::RGB_Set(DWORD p_RGB){
//----------------------------------------------------------------------------
  uRGBA Temp;
  Temp.Pixel=p_RGB; 
  Temp.Alpha=this->RGBA->Alpha;
  this->RGBA->Pixel=Temp.Pixel;   
};
//----------------------------------------------------------------------------

//----------------------------------------------------------------------------
void JFC_RGBA::RGBA_Set(
  unsigned char p_Red, 
  unsigned char p_Green, 
  unsigned char p_Blue, 
  unsigned char p_Alpha
){
//----------------------------------------------------------------------------
  this->RGBA->Red=p_Red;
  this->RGBA->Green=p_Green;  
  this->RGBA->Blue=p_Blue;  
  this->RGBA->Alpha=p_Alpha;  
};
//----------------------------------------------------------------------------

//----------------------------------------------------------------------------
void JFC_RGBA::RGBA_Set(DWORD p_RGBA){
//----------------------------------------------------------------------------
  this->RGBA->Pixel=p_RGBA;
};
//----------------------------------------------------------------------------

//----------------------------------------------------------------------------
unsigned int JFC_RGBA::Red_Get(void){
//----------------------------------------------------------------------------
  return this->RGBA->Red;  
};
//----------------------------------------------------------------------------

//----------------------------------------------------------------------------
unsigned int JFC_RGBA::Green_Get(void){
//----------------------------------------------------------------------------
  return this->RGBA->Green;  
};
//----------------------------------------------------------------------------

//----------------------------------------------------------------------------
unsigned int JFC_RGBA::Blue_Get(void){
//----------------------------------------------------------------------------
  return this->RGBA->Blue;  
};
//----------------------------------------------------------------------------

//----------------------------------------------------------------------------
unsigned int JFC_RGBA::Alpha_Get(void){
//----------------------------------------------------------------------------
  return this->RGBA->Alpha;  
};
//----------------------------------------------------------------------------

//----------------------------------------------------------------------------
DWORD JFC_RGBA::RGB_Get(void){
//----------------------------------------------------------------------------
  uRGBA Temp;
  Temp.Pixel = this->RGBA->Pixel;
  Temp.Alpha=0;
  return Temp.Pixel;   
};
//----------------------------------------------------------------------------

//----------------------------------------------------------------------------
DWORD JFC_RGBA::RGBA_Get(void){
//----------------------------------------------------------------------------
  return this->RGBA->Pixel;  
};
//----------------------------------------------------------------------------


//============================================================================
// end                                   JFC_RGB
//============================================================================

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Michael P

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Joined: 6th Mar 2006

Location: London (UK)

Posted: 1st Jul 2008 18:21

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that's awesome, thanks Benjamin.

Working code:

+ Code Snippet

#include <windows.h>
#include <iostream>

using namespace std;

int main ()
{
	// Create integer and find its size.
	int iInt;
	cout << "Enter a number to transfer: ";
	cin >> iInt;

	// Save the size of an integer.
	int iSize = sizeof(iInt);

	// Create character sequence.
	char * cBuffer = new char[iSize];
	ZeroMemory(cBuffer,iSize);

	// Fill character sequence with bytes from integer.
	for(int n = 0;n<iSize;n++)
	{
		*(int*)&cBuffer[n] = iInt;
	}

	// Create another integer.
	int iIntReturn;

	// Fill integer with bytes from character sequence.
	for(int n = 0;n<iSize; n++)
	{
		iIntReturn = *(int*)&cBuffer[n];
	}

	// Display second integer and wait for input.
	cout << "Second integer: " << iIntReturn << ".\n";
	int Blank;
	cin >> Blank;
	
	// Delete dynamic memory and exit.
	delete[] cBuffer;

	return(0);
}

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Benjamin

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Posted: 1st Jul 2008 18:26

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Watch out, as the array subscript references by chars, not integers, so effectively you should store at [0] followed by [4], then [8], etc.

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Michael P

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Posted: 2nd Jul 2008 17:55

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Urgh, I have a problem

Things are fine when there is just one integer involved but with two or more the numbers returned are not the numbers entered into the buffer. It does allow enough space for each integer (4 bytes) and I've spent a good hour trying to figure out what is wrong (although it is probably something very obvious

). Here is the code:

#include <windows.h>
#include <iostream>

using namespace std;

string sBuffer;

// Returns an integer from the buffer.
int GetInt(void)
{
	// Stores data to return.
	int Return = 0;
	
	// Get size in bytes of what we are receiving.
	int iSize = sizeof(Return);

// Prevent going out of bounds.
	if((int)sBuffer.length() >= iSize)
	{
		// Put relevant bytes into Return.
		for(int n = 0;n<iSize;n++)
		{
			Return = *(int*)&sBuffer[n];
		}

// Erase used bytes.
		sBuffer.erase(0,iSize);
	}
	return(Return);
}

// Adds an integer to the buffer.
void AddInt(int Add)
{
	// Get the position to start adding. 
	int iStart = sBuffer.length();

// Get the size in bytes of what we are adding.
	int iSize = sizeof(Add);

// Get the new end position after adding.
	int iEnd = iStart+iSize;

// Make space for 'Add'.
	sBuffer.resize(iEnd);

// Add each byte of 'Add' to the buffer.
	for(int n = iStart;n<iEnd;n++)
	{
		*(int*)&sBuffer[n] = Add;
	}
}

int main (void)
{
	// Add integers to the buffer.
	int iIntAdded1 = 5000;
	int iIntAdded2 = 24;
	AddInt(iIntAdded1);
	AddInt(iIntAdded2);

// Get integers from the buffer.
	int iIntReturn1 = GetInt();
	int iIntReturn2 = GetInt();
	
	// Display numbers
	cout << "To buffer: " << iIntAdded1 << ", " << iIntAdded2 << ".\n";
	cout << "From buffer: " << iIntReturn1 << ", " << iIntReturn2 << ".\n";

// Wait for input and then exit.
	int Blank;
	cin >> Blank;
	return(0);
}

+ Code Snippet

#include <windows.h>
#include <iostream>

using namespace std;

string sBuffer;

// Returns an integer from the buffer.
int GetInt(void)
{
	// Stores data to return.
	int Return = 0;
	
	// Get size in bytes of what we are receiving.
	int iSize = sizeof(Return);

	// Prevent going out of bounds.
	if((int)sBuffer.length() >= iSize)
	{
		// Put relevant bytes into Return.
		for(int n = 0;n<iSize;n++)
		{
			Return = *(int*)&sBuffer[n];
		}

		// Erase used bytes.
		sBuffer.erase(0,iSize);
	}
	return(Return);
}


// Adds an integer to the buffer.
void AddInt(int Add)
{
	// Get the position to start adding. 
	int iStart = sBuffer.length();

	// Get the size in bytes of what we are adding.
	int iSize = sizeof(Add);

	// Get the new end position after adding.
	int iEnd = iStart+iSize;

	// Make space for 'Add'.
	sBuffer.resize(iEnd);

	// Add each byte of 'Add' to the buffer.
	for(int n = iStart;n<iEnd;n++)
	{
		*(int*)&sBuffer[n] = Add;
	}
}

int main (void)
{
	// Add integers to the buffer.
	int iIntAdded1 = 5000;
	int iIntAdded2 = 24;
	AddInt(iIntAdded1);
	AddInt(iIntAdded2);

	// Get integers from the buffer.
	int iIntReturn1 = GetInt();
	int iIntReturn2 = GetInt();
	
	// Display numbers
	cout << "To buffer: " << iIntAdded1 << ", " << iIntAdded2 << ".\n";
	cout << "From buffer: " << iIntReturn1 << ", " << iIntReturn2 << ".\n";

	// Wait for input and then exit.
	int Blank;
	cin >> Blank;
	return(0);
}

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Benjamin

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Posted: 2nd Jul 2008 18:03

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What's the loop for? If you're only storing/retrieving a single 4-byte integer you can use the code I posted.

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Michael P

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Location: London (UK)

Posted: 2nd Jul 2008 18:23

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Ohh I see how it works now, I assumed that "*(int*)&sBuffer[n] = Add;" only stored one byte at a time when in fact it does all 4.

Thanks again Ben!

Correct code (hopefully):

#include <windows.h>
#include <iostream>

using namespace std;

string sBuffer;

// Returns an integer from the buffer.
int GetInt(void)
{
	// Stores data to return.
	int Return = 0;
	
	// Get size in bytes of what we are receiving.
	int iSize = sizeof(Return);

// Prevent going out of bounds.
	if((int)sBuffer.length() >= iSize)
	{
		// Put relevant bytes into Return.
		Return = *(int*)&sBuffer[0];

// Erase used bytes.
		sBuffer.erase(0,iSize);
	}
	return(Return);
}

// Adds an integer to the buffer.
void AddInt(int Add)
{
	// Get the position to start adding. 
	int iStart = sBuffer.length();

// Get the size in bytes of what we are adding.
	int iSize = sizeof(Add);

// Get the new end position after adding.
	int iEnd = iStart+iSize;

// Make space for 'Add'.
	sBuffer.resize(iEnd);

// Add each byte of 'Add' to the buffer.
	*(int*)&sBuffer[iStart] = Add;
}

int main (void)
{
	// Add integers to the buffer.
	int iIntAdded1 = 5000;
	int iIntAdded2 = 24;
	AddInt(iIntAdded1);
	AddInt(iIntAdded2);

// Get integers from the buffer.
	int iIntReturn1 = GetInt();
	int iIntReturn2 = GetInt();
	
	// Display numbers
	cout << "To buffer: " << iIntAdded1 << ", " << iIntAdded2 << ".\n";
	cout << "From buffer: " << iIntReturn1 << ", " << iIntReturn2 << ".\n";

// Wait for input and then exit.
	int Blank;
	cin >> Blank;
	return(0);
}

+ Code Snippet

#include <windows.h>
#include <iostream>

using namespace std;

string sBuffer;

// Returns an integer from the buffer.
int GetInt(void)
{
	// Stores data to return.
	int Return = 0;
	
	// Get size in bytes of what we are receiving.
	int iSize = sizeof(Return);

	// Prevent going out of bounds.
	if((int)sBuffer.length() >= iSize)
	{
		// Put relevant bytes into Return.
		Return = *(int*)&sBuffer[0];

		// Erase used bytes.
		sBuffer.erase(0,iSize);
	}
	return(Return);
}


// Adds an integer to the buffer.
void AddInt(int Add)
{
	// Get the position to start adding. 
	int iStart = sBuffer.length();

	// Get the size in bytes of what we are adding.
	int iSize = sizeof(Add);

	// Get the new end position after adding.
	int iEnd = iStart+iSize;

	// Make space for 'Add'.
	sBuffer.resize(iEnd);

	// Add each byte of 'Add' to the buffer.
	*(int*)&sBuffer[iStart] = Add;
}

int main (void)
{
	// Add integers to the buffer.
	int iIntAdded1 = 5000;
	int iIntAdded2 = 24;
	AddInt(iIntAdded1);
	AddInt(iIntAdded2);

	// Get integers from the buffer.
	int iIntReturn1 = GetInt();
	int iIntReturn2 = GetInt();
	
	// Display numbers
	cout << "To buffer: " << iIntAdded1 << ", " << iIntAdded2 << ".\n";
	cout << "From buffer: " << iIntReturn1 << ", " << iIntReturn2 << ".\n";

	// Wait for input and then exit.
	int Blank;
	cin >> Blank;
	return(0);
}

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