X-Git-Url: http://nsz.repo.hu/git/?p=musl;a=blobdiff_plain;f=src%2Fmalloc%2Faligned_alloc.c;fp=src%2Fmalloc%2Faligned_alloc.c;h=d623420b42c8427bfce2babe8c1a9ce055a939a0;hp=0000000000000000000000000000000000000000;hb=9bff7c133e73ecfb200614d7a7d386a164a1a61f;hpb=b5289fd749bc4d2637610d712f8fe650f214f1d5

diff --git a/src/malloc/aligned_alloc.c b/src/malloc/aligned_alloc.c
new file mode 100644
index 00000000..d623420b
--- /dev/null
+++ b/src/malloc/aligned_alloc.c
@@ -0,0 +1,51 @@
+#include <stdlib.h>
+#include <stdint.h>
+#include <errno.h>
+
+/* 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 *aligned_alloc(size_t align, size_t len)
+{
+	unsigned char *mem, *new, *end;
+	size_t header, footer;
+
+	if ((align & -align & -sizeof(void *)) != 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];
+	end = mem + (header & -8);
+	footer = ((size_t *)end)[-2];
+	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;
+	}
+
+	((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;
+}