From 0b44a0315b47dd8eced9f3b7f31580cf14bbfc01 Mon Sep 17 00:00:00 2001 From: Rich Felker Date: Sat, 12 Feb 2011 00:22:29 -0500 Subject: initial check-in, version 0.5.0 --- src/malloc/posix_memalign.c | 47 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 47 insertions(+) create mode 100644 src/malloc/posix_memalign.c (limited to 'src/malloc/posix_memalign.c') diff --git a/src/malloc/posix_memalign.c b/src/malloc/posix_memalign.c new file mode 100644 index 00000000..ef86260d --- /dev/null +++ b/src/malloc/posix_memalign.c @@ -0,0 +1,47 @@ +#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. */ + +int posix_memalign(void **res, size_t align, size_t len) +{ + unsigned char *mem, *new, *end; + size_t header, footer; + + if ((align & -align) != align) return EINVAL; + if (len > SIZE_MAX - align) return ENOMEM; + + if (align <= 4*sizeof(size_t)) { + if (!(mem = malloc(len))) + return errno; + *res = mem; + return 0; + } + + if (!(mem = malloc(len + align-1))) + return errno; + + 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); + *res = new; + return 0; + } + + ((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); + *res = new; + return 0; +} -- cgit v1.2.1