Yonka-AntiVirusProject-Bonus.c

#include <stdio.h>
#include <stdlib.h>

#define ARGS_COUNT 4 // Not including the program name
#define ONE_BYTE 1

void myExit(int code);
void checkArgs(int argc);
void extractVirusSignature(FILE* srcFile, int from, int to, FILE* dstFile);

int main(int argc, char** argv)
{
    int from = 0, to = 0;

    checkArgs(argc);
    /*
     * argv[0] = program name
     * argv[1] = infected file
     * argv[2] = virus signature (from)
     * argv[3] = virus signature (to)
     * argv[4] = extract the virus signature to
    */
    from = atoi(argv[2]);
    to = atoi(argv[3]);

    FILE* srcFile = fopen(argv[1], "r");
    if (srcFile == NULL)
    {
        printf("Error to open the file!\n");

        myExit(1);
    }
    FILE* dstFile = fopen(argv[4], "w+");
    if (dstFile == NULL)
    {
        printf("Error to open the file!\n");
        fclose(srcFile);

        myExit(1);
    }

    extractVirusSignature(srcFile, from, to, dstFile);

    printf("- - - Done - - -\n"
           "From file: %s\n"
           "Extracted virus signature from %d to %d\n"
           "Extracted to: %s\n", argv[1], from, to, argv[4]);

    getchar();
    return 0;
}
void extractVirusSignature(FILE* srcFile, int from, int to, FILE* dstFile)
{
    char buffer = 0;
    int currentByte = 0;
    size_t numBytesRead = 0;

    while (!feof(srcFile))
    {
        currentByte++;
        numBytesRead = fread(&buffer, sizeof(char), ONE_BYTE, srcFile);
        if (currentByte >= from && currentByte <= to) // copy data only if the data in the given range (RANGE: from->to)
        {
            fwrite(&buffer, sizeof(char), numBytesRead, dstFile);
        }
    }
}
void checkArgs(int argc)
{
    if (argc != ARGS_COUNT + 1)
    {
        printf("Invalid execution.\nUsage:\n"
            "> extractVirusSign <file_to_extract_virus_sign> "
            "<virus_signature_position_from> "
            "<virus_signature_posotion_to> "
            "<file_to_extract_virus_signature>\n");

        myExit(1);
    }
}
void myExit(int code)
{
    getchar();
    exit(code);
}