From e90b72ec3082588b296956730bd2930cf8d5d671 Mon Sep 17 00:00:00 2001 From: Richard Qin Date: Fri, 10 Jul 2026 11:31:46 +0800 Subject: refactor: promote new architecture to repository root Archive the deprecated implementation under lume-legacy, make the new kernel the default root-level build, and update repository entry points without changing kernel behavior. --- lib/string/memchr.c | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) create mode 100644 lib/string/memchr.c (limited to 'lib/string/memchr.c') diff --git a/lib/string/memchr.c b/lib/string/memchr.c new file mode 100644 index 0000000..d0f670f --- /dev/null +++ b/lib/string/memchr.c @@ -0,0 +1,30 @@ +/* SPDX-License-Identifier: MIT */ +/* Derived from musl libc (Copyright © 2005-2020 Rich Felker, et al.) */ + +#include +#include +#include + +#define SS (sizeof(size_t)) +#define ALIGN (sizeof(size_t)-1) +#define ONES ((size_t)-1/UCHAR_MAX) +#define HIGHS (ONES * (UCHAR_MAX/2+1)) +#define HASZERO(x) ((x)-ONES & ~(x) & HIGHS) + +void *memchr(const void *src, int c, size_t n) +{ + const unsigned char *s = src; + c = (unsigned char)c; +#ifdef __GNUC__ + for (; ((uintptr_t)s & ALIGN) && n && *s != c; s++, n--); + if (n && *s != c) { + typedef size_t __attribute__((__may_alias__)) word; + const word *w; + size_t k = ONES * c; + for (w = (const void *)s; n>=SS && !HASZERO(*w^k); w++, n-=SS); + s = (const void *)w; + } +#endif + for (; n && *s != c; s++, n--); + return n ? (void *)s : 0; +} -- cgit v1.2.3