/*********************
* Name: Yair Benamou.*
* Lesson: 8.         *
* Ex: Mid Project    *
**********************/

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<conio.h>
#include<malloc.h>




// No Prototypes
int fileSize(FILE* pToFile);



/**
The function 'fileLen' get a file and count how much characters he have.

Input: pToFile - Getting the pointer to the file.

Output: numCharacters - The counter.
*/
int fileSize(FILE* pToFile)
{
	int count = 0;
	while (fgetc(pToFile) != EOF) // Counting the chars
	{
		count++;
	}
	return (count);
}



/**
The function 'choseScan' ask the user which scan he wants to do.

Inputs: None.

Outputs: The user's choice.
*/
int choseScan(void)
{
	int choice;

	printf("\nWhich scan you want to do?\n1) FAST SCAN.\n2) REGULAR SCAN.\n");
	scanf("%d", &choice);

	return(choice);
}



/**
The function 'fastScan' gets a file and his size. The function will scan the file
on the fast way: 20% of the file beginning, and 20% from the end.

Input: pToFile - The file to scan
	   pToVirus - The pointer to the virus file.
	   size - The file's size.

Output: 1 if there is a virus.
	    0 if the file is clean.
*/
int fastScan(FILE* pToFile, int size)
{
	float heuristic;
	int i;
	int ch;
	char* virusSign, *pTemp = NULL;


	virusSign = (char*)malloc(sizeof(char) + 1); // +1 for the NULL
	if (!virusSign)
	{
		printf("Unsuccessful malloc!\n");
		return 1;
	}

	heuristic = (float)(size * 0.2); // Getting 20% of the file size.
	fseek(pToFile, 0, SEEK_SET); // To put the seek on the file beginning.

	for (i = 0; i < (int)heuristic; i++)
	{
		ch = fgetc(pToFile);
		printf("%c", ch);

		pTemp = realloc(virusSign, sizeof(char)* i + 1);
		if (!pTemp)
		{
			printf("Unsuccessful allocation!\n");
			return 1;
		}

		*(pTemp + i) = (char)ch;
		virusSign = pTemp;

	}

	printf("\n\n\n");

	for (i = 0; i < strlen(virusSign); i++)
	{
		printf("%c", *(virusSign + i));
	}

	printf("\n");

	free(virusSign);

	return 0;
}



/**
This is the main function of the program, which is responsible
to both start and end the running of the program.
input: None.
output: The program returns 0 upon successful completion of its running (windows convention).
*/
int main(void)
{
	int size;
	FILE* pToFile = fopen("C:\\Users\\User\\Desktop\\Mid Project\\Log.txt", "rb");

	if (!pToFile) // Verifying if the file didn't opened successfuly.
	{
		printf("An error occured opening the file.\n");
		return 1;
	}

	size = fileSize(pToFile); // Getting the file's size
	printf("File Size: %d.\n", size);

	if (choseScan() == 1)
	{
		fastScan(pToFile, size);
	}
	else
	{
		// regularScan();
	}

	fclose(pToFile);
	system("PAUSE");
	return (0);
}