#include "alloc.h"

#include "error.h"

extern char *malloc();

extern void free();

#define ALIGNMENT 16 /* XXX: assuming that this alignment is enough */

#define SPACE 4096 /* must be multiple of ALIGNMENT */

typedef union { char irrelevant[ALIGNMENT]; double d; } aligned;

static aligned realspace[SPACE / ALIGNMENT];

#define space ((char *) realspace)

static unsigned int avail = SPACE; /* multiple of ALIGNMENT; 0<=avail<=SPACE */

/*@null@*//*@out@*/char *alloc(n)

unsigned int n;

{

  char *x;

  n = ALIGNMENT + n - (n & (ALIGNMENT - 1)); /* XXX: could overflow */

  if (n <= avail) { avail -= n; return space + avail; }

  x = malloc(n);

  if (!x) errno = error_nomem;

  return x;

}

void alloc_free(x)

char *x;

{

  if (x >= space)

    if (x < space + SPACE)

      return; /* XXX: assuming that pointers are flat */

  free(x);

}