X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=src%2Fmalloc%2Fmemalign.c;h=55fe68e866253316faeab0076ba78d46b4881f78;hb=6d861ac87491a207e4599c44b61d142f0a601c2d;hp=61f456e48667e6a717802eadc5a471d46a8121a7;hpb=0b44a0315b47dd8eced9f3b7f31580cf14bbfc01;p=musl

diff --git a/src/malloc/memalign.c b/src/malloc/memalign.c
index 61f456e4..55fe68e8 100644
--- a/src/malloc/memalign.c
+++ b/src/malloc/memalign.c
@@ -1,13 +1,55 @@
 #include <stdlib.h>
+#include <stdint.h>
 #include <errno.h>
+#include "libc.h"
 
-void *memalign(size_t align, size_t len)
+/* This function should work with most dlmalloc-like chunk bookkeeping
+ * systems, but it's only guaranteed to work with the native implementation
+ * used in this library. */
+
+void *__memalign(size_t align, size_t len)
 {
-	void *mem;
-	int ret;
-	if ((ret = posix_memalign(&mem, align, len))) {
-		errno = ret;
-		return 0;
+	unsigned char *mem, *new, *end;
+	size_t header, footer;
+
+	if ((align & -align) != align) {
+		errno = EINVAL;
+		return NULL;
+	}
+
+	if (len > SIZE_MAX - align) {
+		errno = ENOMEM;
+		return NULL;
+	}
+
+	if (align <= 4*sizeof(size_t)) {
+		if (!(mem = malloc(len)))
+			return NULL;
+		return mem;
+	}
+
+	if (!(mem = malloc(len + align-1)))
+		return NULL;
+
+	header = ((size_t *)mem)[-1];
+	new = (void *)((uintptr_t)mem + align-1 & -align);
+
+	if (!(header & 7)) {
+		((size_t *)new)[-2] = ((size_t *)mem)[-2] + (new-mem);
+		((size_t *)new)[-1] = ((size_t *)mem)[-1] - (new-mem);
+		return new;
 	}
-	return mem;
+
+	end = mem + (header & -8);
+	footer = ((size_t *)end)[-2];
+
+	((size_t *)mem)[-1] = header&7 | new-mem;
+	((size_t *)new)[-2] = footer&7 | new-mem;
+	((size_t *)new)[-1] = header&7 | end-new;
+	((size_t *)end)[-2] = footer&7 | end-new;
+
+	if (new != mem) free(mem);
+	return new;
 }
+
+weak_alias(__memalign, memalign);