From 331737281c1929c29e679e48783055351ac4fbd9 Mon Sep 17 00:00:00 2001 From: Robert Clausecker Date: Fri, 8 Sep 2023 17:11:55 -0400 Subject: [PATCH] lib/libc/amd64/string: implement strnlen(3) trough memchr(3) Now that we have an optimised memchr(3), we can use it to implement strnlen(3) with better perofrmance. Sponsored by: The FreeBSD Foundation Approved by: mjg MFC after: 1 week MFC to: stable/14 Differential Revision: https://reviews.freebsd.org/D41598 --- lib/libc/amd64/string/Makefile.inc | 3 ++- lib/libc/amd64/string/strnlen.c | 42 ++++++++++++++++++++++++++++++ 2 files changed, 44 insertions(+), 1 deletion(-) create mode 100644 lib/libc/amd64/string/strnlen.c diff --git a/lib/libc/amd64/string/Makefile.inc b/lib/libc/amd64/string/Makefile.inc index 7c6a1f42959..73973a6d69d 100644 --- a/lib/libc/amd64/string/Makefile.inc +++ b/lib/libc/amd64/string/Makefile.inc @@ -11,7 +11,8 @@ MDSRCS+= \ strcat.S \ strchrnul.S \ strcmp.S \ + strcpy.c \ strcspn.S \ strlen.S \ - strcpy.c \ + strnlen.c \ strspn.S diff --git a/lib/libc/amd64/string/strnlen.c b/lib/libc/amd64/string/strnlen.c new file mode 100644 index 00000000000..9db4ce30dfd --- /dev/null +++ b/lib/libc/amd64/string/strnlen.c @@ -0,0 +1,42 @@ +/*- + * Copyright (c) 2023 The FreeBSD Foundation + * + * This software was developed by Robert Clausecker + * under sponsorship from the FreeBSD Foundation. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ''AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE + */ + +#include +#include + +char *__memchr(const void *, int, size_t); + +size_t +strnlen(const char *s, size_t maxlen) +{ + const char *loc; + + loc = __memchr(s, '\0', maxlen); + + return (loc == NULL ? maxlen : (size_t)(loc - s)); +}