X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=src%2Fmalloc%2Fcalloc.c;h=bf6bddca3fd81aca3b246391e34ea9afbc95ed3e;hb=3733c831f293b3bbfd0e51faec8ee71112c62c3e;hp=9d5745628bb5667decc76a6a244cb450f39b92d8;hpb=0b44a0315b47dd8eced9f3b7f31580cf14bbfc01;p=musl

diff --git a/src/malloc/calloc.c b/src/malloc/calloc.c
index 9d574562..bf6bddca 100644
--- a/src/malloc/calloc.c
+++ b/src/malloc/calloc.c
@@ -1,23 +1,45 @@
 #include <stdlib.h>
-#include <errno.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);
 }