From b6f2750ca8cd488ddda57380c5f5b03ed9facf45 Mon Sep 17 00:00:00 2001 From: Ian Moffett Date: Sun, 15 Dec 2024 22:48:26 -0500 Subject: kernel: lib: Add atoi() Signed-off-by: Ian Moffett --- sys/lib/string/atoi.c | 51 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 51 insertions(+) create mode 100644 sys/lib/string/atoi.c (limited to 'sys/lib/string/atoi.c') diff --git a/sys/lib/string/atoi.c b/sys/lib/string/atoi.c new file mode 100644 index 0000000..772cf29 --- /dev/null +++ b/sys/lib/string/atoi.c @@ -0,0 +1,51 @@ +/* + * Copyright (c) 2023-2024 Ian Marco Moffett and the Osmora Team. + * All rights reserved. + * + * 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. + * 3. Neither the name of Hyra nor the names of its + * contributors may be used to endorse or promote products derived from + * this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT OWNER 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 + +#define IS_DIGIT(C) ((C >= '0' && C <= '9')) + +int +atoi(char *s) +{ + int n, sign; + + while (*s == ' ') { + ++s; + } + + sign = (*s == '-') ? -1 : 1; + if (*s == '+' || *s == '-') { + s++; + } + for (n = 0; IS_DIGIT(*s); ++s) { + n = 10 * n + (*s - '0'); + } + return sign * n; +} -- cgit v1.2.3