From c99cadbe02f659264cecb44c053d96383631147d Mon Sep 17 00:00:00 2001 From: Mattias Andrée Date: Tue, 17 Nov 2015 05:50:23 +0100 Subject: rearrange files MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Signed-off-by: Mattias Andrée --- src/string/str/strcncpy.c | 54 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 54 insertions(+) create mode 100644 src/string/str/strcncpy.c (limited to 'src/string/str/strcncpy.c') diff --git a/src/string/str/strcncpy.c b/src/string/str/strcncpy.c new file mode 100644 index 0000000..5036c7d --- /dev/null +++ b/src/string/str/strcncpy.c @@ -0,0 +1,54 @@ +/** + * 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 + + + +/** + * Copy a memory segment to another, non-overlapping, segment, + * stop when a NUL byte or a specified byte is encountered. + * + * This is a slibc extension added for completeness. + * It is only available if GNU extensions are available. + * + * @param whither The destination memory segment. + * @param whence The source memory segment. + * @param c The stop byte. + * @param maxlen The maximum number of bytes to copy. + * NOTE that if the resulting string at least this + * long, no NUL byte will be written to `whither'. + * On the otherhand, if the resultnig string is + * shorter, `whither` will be filled with NUL bytes + * until this amount of bytes have been written. + * @return `NULL` if `c` was not encountered, otherwise + * the position of `c` translated to `whither`, + * that is, the address of `whither` plus the + * number of copied characters; the address of + * one character passed the last written non-NUL + * character. + */ +char* strcncpy(char* restrict whither, const char* restrict whence, int c, size_t maxlen) +{ + const char* stop = memchr(whence, c, maxlen); + size_t n = stop == NULL ? strnlen(whence, maxlen) : (size_t)(stop - whence); + char* r = stop == NULL ? NULL : (whither + n); + memcpy(whither, whence, n); + memset(whither, 0, maxlen - n); + return r; +} + -- cgit v1.2.3-70-g09d2