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)25void 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