#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
#include <errno.h>
+#include "dynlink.h"
+
+static size_t mal0_clear(char *p, size_t n)
+{
+ const size_t pagesz = 4096; /* arbitrary */
+ if (n < pagesz) return n;
+#ifdef __GNUC__
+ typedef uint64_t __attribute__((__may_alias__)) T;
+#else
+ typedef unsigned char T;
+#endif
+ char *pp = p + n;
+ size_t i = (uintptr_t)pp & (pagesz - 1);
+ for (;;) {
+ pp = memset(pp - i, 0, i);
+ if (pp - p < pagesz) return pp - p;
+ for (i = pagesz; i; i -= 2*sizeof(T), pp -= 2*sizeof(T))
+ if (((T *)pp)[-1] | ((T *)pp)[-2])
+ break;
+ }
+}
+
+static int allzerop(void *p)
+{
+ return 0;
+}
+weak_alias(allzerop, __malloc_allzerop);
void *calloc(size_t m, size_t n)
{
- void *p;
- size_t *z;
if (n && m > (size_t)-1/n) {
errno = ENOMEM;
return 0;
}
n *= m;
- p = malloc(n);
- if (!p) return 0;
- /* Only do this for non-mmapped chunks */
- if (((size_t *)p)[-1] & 7) {
- /* Only write words that are not already zero */
- m = (n + sizeof *z - 1)/sizeof *z;
- for (z=p; m; m--, z++) if (*z) *z=0;
- }
- return p;
+ void *p = malloc(n);
+ if (!p || (!__malloc_replaced && __malloc_allzerop(p)))
+ return p;
+ n = mal0_clear(p, n);
+ return memset(p, 0, n);
}