Split PDF with GS and a little addon

Hello together
Please i have here a little toy to learn and for "possible" usage.
the goal are that i need to split me pdf document to single sides.

with the Appl GS, i can this do without problem, but i need to edit
any time my batch script. here i was thinking with this little app
that i have here i can do any workaround, and ask how meny pages you have, and this will do automatic this split.

Please are this a possible realistic way??
thanks meny time for your possible help
regards and thanks
Mauri

Code:

---


#include <stdio.h>
#include <process.h>


int main()
{
    int choice=0;


    printf("\n******* this App will split your PDF in single PDF Sites **********\n");
    printf("1. how meny pages have your PDF 1\n");
    printf("2. how meny pages have your PDF 2\n");
    printf("3. how meny pages have your PDF 3\n");
    printf("4. how meny pages have your PDF 4\n");
    printf("5. how meny pages have your PDF 5\n");
    printf("6. how meny pages have your PDF 6\n");
    printf("7. how meny pages have your PDF 7\n");


    printf("** Enter your choice :");
    scanf("%d",&choice);


    switch(choice)
    {
        case 1:
            system("C:\Program Files\gs\gs9.53.3\bin\gswin64.exe -dBATCH -dNOPAUSE -sDEVICE=pdfwrite -dFirstPage=1 -dLastPage=1 -sOutputFile=%%d.pdf combine.pdf");
            break;
        case 2:
            system("C:\Program Files\gs\gs9.53.3\bin\gswin64.exe -dBATCH -dNOPAUSE -sDEVICE=pdfwrite -dFirstPage=2 -dLastPage=2 -sOutputFile=%%d.pdf combine.pdf");
            break;
        case 3:
            system("C:\Program Files\gs\gs9.53.3\bin\gswin64.exe -dBATCH -dNOPAUSE -sDEVICE=pdfwrite -dFirstPage=1 -dLastPage=3 -sOutputFile=%%d.pdf combine.pdf");
            break;
        case 4:
            system("C:\Program Files\gs\gs9.53.3\bin\gswin64.exe -dBATCH -dNOPAUSE -sDEVICE=pdfwrite -dFirstPage=1 -dLastPage=4 -sOutputFile=%%d.pdf combine.pdf");
            break;
        case 5:
            system("C:\Program Files\gs\gs9.53.3\bin\gswin64.exe -dBATCH -dNOPAUSE -sDEVICE=pdfwrite -dFirstPage=1 -dLastPage=5 -sOutputFile=%%d.pdf combine.pdf");
            break;
        case 6:
            system("C:\Program Files\gs\gs9.53.3\bin\gswin64.exe -dBATCH -dNOPAUSE -sDEVICE=pdfwrite -dFirstPage=1 -dLastPage=6 -sOutputFile=%%d.pdf combine.pdf");
            break;
        case 7:
            system("C:\Program Files\gs\gs9.53.3\bin\gswin64.exe -dBATCH -dNOPAUSE -sDEVICE=pdfwrite -dFirstPage=1 -dLastPage=7 -sOutputFile=%%d.pdf combine.pdf");
            break;
        default:
            printf("\n Invalid choice !!!");
    }


    return 0;
}

---

To be honest, you'd be better off writing this as a batch script (.bat or .cmd) file to begin with.

Code:

---

#include <stdio.h>

int main ( ) {
  // backslashes need quoting
  // the whole program name needs to be in double "" since it contains spaces
  const char *program = "\"C:\\Program Files\\gs\\gs9.53.3\\bin\\gswin64.exe\"";
  const char *fixOpts = "-dBATCH -dNOPAUSE -sDEVICE=pdfwrite";
  char pageChoices[100];
  char fileChoices[100];
  char wholeCommand[1000];
  int choice;

  printf("** Enter your choice :");
  scanf("%d",&choice);

  sprintf(pageChoices,"-dFirstPage=1 -dLastPage=%d", choice);
  sprintf(fileChoices,"-sOutputFile=%%d.pdf combine.pdf");    // what is %%d here?

  sprintf(wholeCommand, "%s %s %s %s",
          program, fixOpts, pageChoices, fileChoices);

  printf("Calling system with\n%s\n",wholeCommand);
  //system(wholeCommand);
}


$ gcc foo.c
$ ./a.out
** Enter your choice :3
Calling system with
"C:\Program Files\gs\gs9.53.3\bin\gswin64.exe" -dBATCH -dNOPAUSE -sDEVICE=pdfwrite -dFirstPage=1 -dLastPage=3 -sOutputFile=%d.pdf combine.pdf

---

That's a brute force way of doing it.

You can construct a string to pass to system(). Use snprintf(), and test it first by outputting the command. Then write a real program that passes it to system().

I strongly recommend to avoid using system() in any project. And I think Salem is right saying this is better suited to a script/batch file. Just as an exercise here's my implementation using execv(), instead:

Code:

---

/* cutpdf.c */
#ifndef _WIN32
# error This is for Windows only.
#endif

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

#include <io.h>
#include <process.h>

// Windows don't have asprintf() function. Emulate one.
static int asprintf ( char **, char *, ... );

int main ( int argc, char *argv[] )
{
  unsigned long first, last;
  char *p;

  if ( argc != 5 )
  {
    fputs ( "Usage: cutpdf <first page> <last page> <inpdffile> <outpdffile>\n",
            stderr );
    return EXIT_FAILURE;
  }

  char *argv_[8] = { "\"C:\\Program Files\\gs\\gs9.53.3\\bin\\gswin64.exe\"",
                    "-dBATCH", "-dNOPAUSE", "-sDEVICE=pdfwrite"
                  };

  // Converts and verify validity of arguments.
  first = strtoul ( argv[1], &p, 10 );

  if ( *p || errno == ERANGE )
  {
    fputs ( "Error: First page invalid.\n", stderr );
    return EXIT_FAILURE;
  }

  last = strtoul ( argv[2], &p, 10 );

  if ( *p || errno == ERANGE )
  {
    fputs ( "Error: First page invalid.\n", stderr );
    return EXIT_FAILURE;
  }

  // last page must be >= first page.
  if ( first > last )
  {
    fputs ( "Error: First page cannot be greater than the last page.\n", stderr );
    return EXIT_FAILURE;
  }

  // Checks if input file is readable.
  if ( _access ( argv[3], 4 ) )
  {
    fprintf ( stderr, "Error: Cannot read '%s'.\n", argv[3] );
    return EXIT_FAILURE;
  }

  asprintf ( &argv_[4], "-dFirstPage=%lu", first );
  asprintf ( &argv_[5], "-dLastPage=%lu", last );
  asprintf ( &argv_[6], "-sOutputFile=\"%s\"", argv[3] );
  argv_[7] = argv[4];
  // Or change to:
  //    asprintf( &argv_[7], "\"%s\"", argv[4] );

  _execv ( argv_[0], ( const char *const * ) argv_ );

  // We'll get here only if _execv() fails.
  // Free the allocated strings.
  free ( argv_[4] );
  free ( argv_[5] );
  free ( argv_[6] );
  // add 'free( argv_[7] );' if you use asprintf above.

  fputs ( "ERROR: Process not executed.\n", stderr );
  return EXIT_FAILURE;
}

int asprintf ( char **p, char *fmt, ... )
{
  char c;
  int size;
  va_list args;

  va_start ( args, fmt );

  if ( ( size = vsnprintf ( &c, sizeof c, fmt, args ) ) >= 0 )
  {
    *p = malloc ( size + 1 );
    vsprintf ( *p, fmt, args );
  }

  va_end ( args );

  return size;
}

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