From 6d861ac87491a207e4599c44b61d142f0a601c2d Mon Sep 17 00:00:00 2001 From: Rich Felker Date: Thu, 4 Jul 2013 23:58:16 -0400 Subject: 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. --- src/malloc/aligned_alloc.c | 48 ++-------------------------------------------- 1 file changed, 2 insertions(+), 46 deletions(-) (limited to 'src/malloc/aligned_alloc.c') diff --git a/src/malloc/aligned_alloc.c b/src/malloc/aligned_alloc.c index c6386629..cc0a8012 100644 --- a/src/malloc/aligned_alloc.c +++ b/src/malloc/aligned_alloc.c @@ -1,52 +1,8 @@ #include -#include -#include -/* 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); } -- cgit v1.2.1