//---------------------------------------------------------------------------
//Name:   File copying (working with binary files)
//Author: Przemyslaw Kudlacik
//---------------------------------------------------------------------------

#include <stdio.h>

//---------------------------------------------------------------------------

int main(int argc, char* argv[])
{
    //definition of variables

    FILE * src_filevar,* dst_filevar;     //file variables - handles to files in a program
    char src_fname[256], dst_fname[256];  //file names
    char buffer[4096];     //buffer
    int  read_count,write_count;
    long total_read,total_written;

    //reading file names

    src_fname[0] = dst_fname[0] = 0; //clear strings - first character = end of string
    printf("Type source file name: ");
    scanf("%s",src_fname);
    printf("Type destination file name: ");
    scanf("%s",dst_fname);

    //1. open the files

      //fopen: first param. = file name, second param. = open mode ("r"-reading, "b"-binary)
    src_filevar = fopen(src_fname,"rb");

      //finish if file not opened - work with file ONLY if fopen succeeded
    if (src_filevar == NULL) {
      //file not opened - probably doesn't exist
      printf("Couldn't open file : '%s'\n",src_fname);
      fflush(stdin);
      getc(stdin);    //wait for user to press any key
      return 1;       //end program
    }

      //open file for reading
    dst_filevar = fopen(dst_fname,"rb");

      //finish if file opened (exists) - don't want to destroy it
    if (dst_filevar != NULL) {
      //file opened - exists
      printf("File '%s' already exists.\n",dst_fname);
      fflush(stdin);
      getc(stdin);    //wait for user to press any key

      fclose(src_filevar); //close source file
      return 2;       //end program
    }

      //open file for writing
    dst_filevar = fopen(dst_fname,"wb");

      //finish if couldn't open (create) file for writing
    if (dst_filevar == NULL) {
      //file not opened - insufficient permissions or disk full
      printf("Couldn't open file : '%s'\n",dst_fname);
      fflush(stdin);
      getc(stdin);    //wait for user to press any key

      fclose(src_filevar); //close source file
      return 2;       //end program
    }

    //2. working with files - copying (moving data in a loop from source to destination)
    printf("Copying '%s' to '%s'. Please wait ...\n",src_fname,dst_fname);

    total_read = total_written = 0;

    // work while reading to buffer is possible
    while ( read_count = fread( (void *)buffer, 1, 4096, src_filevar) ) {

      // try to write bytes just read to a file
      write_count = fwrite( (void *)buffer, 1, read_count, dst_filevar);

      //count statistics
      total_read = total_read + read_count;
      total_written = total_written + write_count;

      //check errors
      if (read_count != write_count){
        printf("COPY ERROR - further writing impossible ...");
        break;
      }
    }

    printf("\nCopying finished.\n");
    printf("Bytes read    : %d\nBytes written : %d\n",total_read,total_written);
    fflush(stdin);
    getc(stdin);    //wait for user to press any key

    //3. work with files is finished - close the files

    fclose(src_filevar);
    fclose(dst_filevar);

    return 0;
}
//---------------------------------------------------------------------------