diff options
Diffstat (limited to 'alloc.c')
-rw-r--r-- | alloc.c | 32 |
1 files changed, 32 insertions, 0 deletions
@@ -0,0 +1,32 @@ +#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); +} |