From 9bff7c133e73ecfb200614d7a7d386a164a1a61f Mon Sep 17 00:00:00 2001 From: Rich Felker Date: Sat, 25 Aug 2012 23:15:13 -0400 Subject: implement "low hanging fruit" from C11 based on Gregor's patch sent to the list. includes: - stdalign.h - removing gets in C11 mode - adding aligned_alloc and adjusting other functions to use it - adding 'x' flag to fopen for exclusive mode --- src/malloc/aligned_alloc.c | 51 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 51 insertions(+) create mode 100644 src/malloc/aligned_alloc.c (limited to 'src/malloc/aligned_alloc.c') 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 +#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 *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; +} -- cgit v1.2.1