Thread: Input problems with DJGPP?

Hi,

I´ve written this program to input some data, and make some calculation on this data. Problem is that I cannot get the input working. I´ve copied the code from another program of mine where there are no problems. I´m using DJGPP, and I´ve tried to compile it on Solaris too. On Solaris it works fine - THE SAME CODE!!1

Can anyone help me explain this??

Code is as goes:

Code:

#include <math.h>
#include <stdlib.h>
#include <fstream>
#include <iostream>
using namespace std;

void calcProbs(unsigned char* data ,int* probs,int size);
double getEntropy(int* probs,int size);
void makeDiffs(unsigned char* data,int size);

#define MAXFILESIZE 1000000

int main(int argc,char** argv){
	unsigned char* data;					// Data buffer
	unsigned char* data2;				// Data buffer 
	int i,j;									// Loop vars
	int probs[256];						// Probability vars
	double entropy;						// Calculated Entropy
	ifstream in;							// Input Filestream
	char* temp;								// Temporary var


	if(argc!=2){ cerr << "Wrong number of arguments" << endl; return 0;}

	data=(unsigned char*) malloc(MAXFILESIZE);		// Alloc some memory
	if(data==NULL){ return 0; } 	

	data2=(unsigned char*) malloc(MAXFILESIZE);		// Alloc some memory
	if(data2==NULL){ free(data); return 0; } 	

	i=0;
	in.open(argv[1],ifstream::in);						// open file
	while(in.good()){
		data[i++]=in.get();
	}
	in.close();													// close file
																	// Read input!
	
	cout << i << endl;										// Output numbers of bytes read

	calcProbs(data,probs,i);
	entropy=getEntropy(probs,i);	
	cout << "original entropy: " <<  entropy << endl;

	makeDiffs(data,i);
	calcProbs(data,probs,i);
	entropy=getEntropy(probs,i);	
	cout << "difference entropy: " << entropy << endl;

	free(data);
	free(data2);
}

void calcProbs(unsigned char* data ,int* probs,int size){
	int i;
	unsigned char c;
	for(i=0;i<256;i++){
		probs[i]=0;
	}	
	for(i=0;i<size;i++){
		c=data[i];
		probs[c]++;
	}
}
double getEntropy(int* probs,int size){
	int i;
	double size2,temp,temp2;
	temp2=0.0;
	size2=(double) size;
	
	for(i=0;i<256;i++){
		if(probs[i]){
			temp=(double) probs[i];
			temp/=size2;
			temp2+=temp*log(temp);
		}
	}
	temp2/=log(2.0);	
	temp2=-temp2;
	return temp2;
}



void makeDiffs(unsigned char* data,int size){
	unsigned char c,d;
	int i;
	c=0;
	for(i=0;i<size;i++){
		d=data[i];
		data[i]=d-c;
		c=d;
	}	
}