move core memalign code from aligned_alloc to __memalign

there are two motivations for this change. one is to avoid
gratuitously depending on a C11 symbol for implementing a POSIX
function. the other pertains to the documented semantics. C11 does not
define any behavior for aligned_alloc when the length argument is not
a multiple of the alignment argument. posix_memalign on the other hand
places no requirements on the length argument. using __memalign as the
implementation of both, rather than trying to implement one in terms
of the other when their documented contracts differ, eliminates this
confusion.

diff --git a/src/malloc/aligned_alloc.c b/src/malloc/aligned_alloc.c
index c63866295339e3373b0bb8978750aa34a6fb4efe..cc0a801208712a9f31759690e55e3eabfd7c99f6 100644 (file)
--- a/src/malloc/aligned_alloc.c
+++ b/src/malloc/aligned_alloc.c
@@ -1,52 +1,8 @@
 #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 *__memalign(size_t, size_t);
 
 void *aligned_alloc(size_t align, size_t len)
 {
-       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;
-       }
-
-       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;
+       return __memalign(align, len);
 }

diff --git a/src/malloc/memalign.c b/src/malloc/memalign.c
index a594c636884f08c331d6dfc1ebc290b45b5b1a7c..55fe68e866253316faeab0076ba78d46b4881f78 100644 (file)
--- a/src/malloc/memalign.c
+++ b/src/malloc/memalign.c
@@ -1,7 +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)
 {
-       return aligned_alloc(align, len);
+       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;
+       }
+
+       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);

diff --git a/src/malloc/posix_memalign.c b/src/malloc/posix_memalign.c
index ad4d8f473015e378ad1025363cd68507ec539f18..cf67db63be0eb809335258c7fc8e39aa4236057c 100644 (file)
--- a/src/malloc/posix_memalign.c
+++ b/src/malloc/posix_memalign.c
@@ -1,10 +1,12 @@
 #include <stdlib.h>
 #include <errno.h>
 
+void *__memalign(size_t, size_t);
+
 int posix_memalign(void **res, size_t align, size_t len)
 {
        if (align < sizeof(void *)) return EINVAL;
-       void *mem = aligned_alloc(align, len);
+       void *mem = __memalign(align, len);
        if (!mem) return errno;
        *res = mem;
        return 0;