/**
 * sort.c - A sort utility, based on code from K&R.
 */

// +---------+--------------------------------------------------------
// | Headers |
// +---------+

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

#include "readlines.h"
#include "writelines.h"
#include "qsort.h"
#include "swap.h"


// +-----------+------------------------------------------------------
// | Constants |
// +-----------+

#define MAXLINES 5000   /* max #lines to be sorted */ 


// +---------+--------------------------------------------------------
// | Globals |
// +---------+

char *lineptr[MAXLINES]; /* pointers to text lines */


// +--------------------------+---------------------------------------
// | Function Predeclarations |
// +--------------------------+

int numcmp(const char *, const char *);


// +------+-----------------------------------------------------------
// | Main |
// +------+

/* sort input lines */ 
int
main (int argc, char *argv[]) 
{
  int nlines;     /* number of input lines read */ 
  int (*comparator)(const char *, const char *);

  comparator = strcmp;

  if ((argc > 1) && (strcmp(argv[1], "-n") == 0))
    comparator = numcmp;
  
  if ((nlines = readlines(lineptr, MAXLINES)) >= 0) 
    { 
      kr_qsort ((char**) lineptr, 0, nlines-1, comparator);
      writelines(lineptr, nlines); 
      return 0;
    }
  else
    { 
       printf("input too big to sort\n"); 
       return 1;
    }
} // main

// +-----------------------+------------------------------------------
// | Function Declarations |
// +-----------------------+

int
numcmp (const char *s1, const char *s2)
{
  double v1, v2;
  v1 = atof (s1);
  v2 = atof (s2);
  if (v1 < v2)
    {
#ifdef DEBUG
      printf ("%lf (%s) < %lf (%s)\n", v1, s1, v2, s2);
#endif
      return -1;
    }
  else if (v1 > v2)
    {
#ifdef DEBUG
      printf ("%lf (%s) > %lf (%s)\n", v1, s1, v2, s2);
#endif
      return 1;
    }
  else
    {
#ifdef DEBUG
      printf ("%lf (%s) == %lf (%s)\n", v1, s1, v2, s2);
#endif
      return 0;
    }
} // numcmp