/*
 *    TITLE:    TEST.C
 *
 *    Test for HEAP program.
 *
 *    It turns out that the program needed some massaging.  It did
 *    not display behavior I wanted it to, at its first try.
 *
 *    I left the trail code of my experiments in.
 *
 *    All programs were developed on an IBM PC/XT having an
 *    Intel 386 inboard.
 *    Compiler:      MS C 5.1
 *    OS:            PC DOS 3.3
 *
 *    Avi Farah.
 */




#include <stdio.h>
#include <malloc.h>
#include "heap.h"




/*
 *    #defines
 */
#define  LEN   20




/*
 *    Prototypes
 */
int   main( void );
int   dummy1( void );
int   dummy2( void );




/*************************   main   ***************************************/

int  main()
   {
   char  *p, *q;
   char far *fp;
   int   err;

   MEMTRACE();          // Will report on the amount of local heap and stack
   HEAPLOOK('\xCC');    // Initial look at the local/global heaps.

   /*
    *    Dummy mallocs
    */
   if ((p = malloc(LEN)) == NULL)
      {
      printf("p = NULL cannot allocate local memory\n");
      return 1;
      }

   if ((q = malloc(LEN)) == NULL)
      {
      printf("q = NULL cannot allocate local memory\n");
      return 2;
      }

/*
 *    Massaged code
 */
#  if 0
   err = dummy1();
   if (err)
      return err;
#  endif

   MEMTRACE();
   HEAPLOOK('\xCC');    // mid point

   /*
    *    Dummy malloc
    */
   if ((fp = _fmalloc(LEN)) == NULL)
      {
      printf("fp == NULL cannot allocate global memory\n");
      return 3;
      }

   err = dummy2();
   if (err)
      return err;

   MEMTRACE();
   HEAPLOOK('\xCC');    // Final HEAPLOOK()

   _ffree(fp);
   free(q);
   free(p);

   return NULL;
   }   /* main */




/******************************   dummy1   **********************************/

int  dummy1()
   {
   char  *p;
   char far *fp = 0;
   register unsigned lc;

   if ((p = malloc(LEN)) == NULL)
      {
      printf("p = NULL cannot allocate local memory\n");
      return 4;
      }

   /*
    *    Overflow !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
    */
   for (lc = 0; lc < LEN; ++lc)
      p[lc] = lc;
   p[lc] = '\0';        // One byte overflow

   free(p);

   return NULL;
   }   /* dummy1 */




/******************************   dummy2   **********************************/

int  dummy2()
   {
   char  *p = 0;
   char far *fp;
   register unsigned lc;

   if ((fp = _fmalloc(LEN)) == NULL)
      {
      printf("fp == NULL cannot allocate global memory\n");
      return 3;
      }

   /*
    *    Overflow !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
    */
   for (lc = 0; lc < LEN + 3; ++lc)    // Overflow
      fp[lc] = lc;

   _ffree(fp);

   return NULL;
   }   /* dummy2 */