From 26da2bbeb9781782b1242acc1668f649c336d65f Mon Sep 17 00:00:00 2001 From: Mattias Andrée Date: Mon, 31 Aug 2015 04:15:39 +0200 Subject: add strlen and wcslen MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Signed-off-by: Mattias Andrée --- src/string/strlen.c | 53 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 53 insertions(+) create mode 100644 src/string/strlen.c (limited to 'src/string') diff --git a/src/string/strlen.c b/src/string/strlen.c new file mode 100644 index 0000000..7023cc0 --- /dev/null +++ b/src/string/strlen.c @@ -0,0 +1,53 @@ +/** + * slibc — Yet another C library + * Copyright © 2015 Mattias Andrée (maandree@member.fsf.org) + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see . + */ +#include +#include + + + +/** + * Returns the number of bytes in a NUL-terminated + * string. This excludes the NUL byte. + * + * @param str The string. + * @return The number of bytes before the first NUL byte. + */ +size_t strlen(const char* str) +{ + /* TODO optimise strlen */ + char* s = str; + while (*str++); + return (size_t)(s - 1 - str); +} + + +/** + * Variant of `strlen` that only inspects the + * beginning of s string. + * + * @param str The string. + * @param maxlen The number of bytes to inspect, at most. + * @return The number of bytes before, the first NUL byte. + * `maxlen` if no NUL byte was found. + */ +size_t strnlen(const char* str, size_t maxlen) +{ + const char* end = memchr(str, 0, maxlen); + return end == NULL ? maxlen : (size_t)(end - str); +} + -- cgit v1.2.3-70-g09d2