/* heapchk.c (emx+gcc) -- Copyright (c) 1990-1993 by Eberhard Mattes */

#include <sys/emx.h>
#include <stdlib.h>
#include <string.h>
#include "malloc2.h"

#if !defined (_LIBCDLL)
static int dummy;
#endif

#define HEAP_NO_FILL 0xf7dc6a4e /* illegal fill value */

static int _heapset2 (unsigned fill);


int _heapchk (void)
{
  return (_heapset (HEAP_NO_FILL));
}


int _heapset (unsigned fill)
{
  int r;

  HEAP_LOCK;
  r = _heapset2 (fill);
  HEAP_UNLOCK;
  return (r);
}


static int _heapset2 (unsigned fill)
{
  size_t *p, *last;
  size_t len, next;
  int met_rover;

  met_rover = 0;
  if (rover == NULL && bottom == NULL && top == NULL)
    return (_HEAPEMPTY);
  if (rover == NULL || bottom == NULL || top == NULL)
    return (_HEAPBADBEGIN);
  if ((size_t)bottom >= (size_t)top)
    return (_HEAPBADBEGIN);
  if (((size_t)bottom & 3) != 0 || ((size_t)top & 3) != 0)
    return (_HEAPBADBEGIN);
#if !defined (_LIBCDLL)
  if ((size_t)bottom <= (size_t)&dummy)
    return (_HEAPBADBEGIN);
#endif
  last = sbrk (0);
  if ((size_t)top >= (size_t)last)
    return (_HEAPBADEND);
  if (*top != END_OF_HEAP)
    return (_HEAPBADEND);
  p = bottom;
  while (p != top)
    {
      if (*p == END_OF_HEAP)
        return (_HEAPBADNODE);
      len = *p;
      if (len > 0x7fffffff)
        return (_HEAPBADNODE);
      next = (size_t)p + sizeof (size_t) + (len & ~3);
      if (next <= (size_t)p || next > (size_t)top || (len & 2))
        return (_HEAPBADNODE);
      if (fill != HEAP_NO_FILL && (len & 1))
        memset ((char *)p + sizeof (size_t), (int)fill, len & ~3);
      if (p == rover)
        ++met_rover;
      p = (size_t *)next;
    }
  if (met_rover != 1)
    return (_HEAPBADROVER);
  return (_HEAPOK);
}