1 #include "alloc.h"
2 #include "error.h"
3 extern char *malloc();
4 extern void free();
5 
6 #define ALIGNMENT 16 /* XXX: assuming that this alignment is enough */
7 #define SPACE 2048 /* must be multiple of ALIGNMENT */
8 
9 typedef union { char irrelevant[ALIGNMENT]; double d; } aligned;
10 static aligned realspace[SPACE / ALIGNMENT];
11 #define space ((char *) realspace)
12 static unsigned int avail = SPACE; /* multiple of ALIGNMENT; 0<=avail<=SPACE */
13 
alloc(n)14 /*@null@*//*@out@*/char *alloc(n)
15 unsigned int n;
16 {
17   char *x;
18   n = ALIGNMENT + n - (n & (ALIGNMENT - 1)); /* XXX: could overflow */
19   if (n <= avail) { avail -= n; return space + avail; }
20   x = malloc(n);
21   if (!x) errno = error_nomem;
22   return x;
23 }
24 
alloc_free(x)25 void alloc_free(x)
26 char *x;
27 {
28   if (x >= space)
29     if (x < space + SPACE)
30       return; /* XXX: assuming that pointers are flat */
31   free(x);
32 }
33