diff options
Diffstat (limited to 'lib/string-desc-contains.c')
-rw-r--r-- | lib/string-desc-contains.c | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/lib/string-desc-contains.c b/lib/string-desc-contains.c new file mode 100644 index 0000000000..c02617629e --- /dev/null +++ b/lib/string-desc-contains.c @@ -0,0 +1,44 @@ +/* String descriptors. + Copyright (C) 2023 Free Software Foundation, Inc. + + This file is free software: you can redistribute it and/or modify + it under the terms of the GNU Lesser General Public License as + published by the Free Software Foundation, either version 3 of the + License, or (at your option) any later version. + + This file 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 Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with this program. If not, see <https://www.gnu.org/licenses/>. */ + +/* Written by Bruno Haible <bruno@clisp.org>, 2023. */ + +#ifdef HAVE_CONFIG_H +# include "config.h" +#endif + +/* Specification. */ +#include "string-desc.h" + +#include <string.h> + + +/* This function is in a separate compilation unit, because not all users + of the 'string-desc' module need this function and it depends on 'memmem' + which — depending on platforms — costs up to 2 KB of binary code. */ + +ptrdiff_t +string_desc_contains (string_desc_t haystack, string_desc_t needle) +{ + if (needle._nbytes == 0) + return 0; + void *found = + memmem (haystack._data, haystack._nbytes, needle._data, needle._nbytes); + if (found != NULL) + return (char *) found - haystack._data; + else + return -1; +} |