xref: /aosp_15_r20/external/llvm-libc/src/string/strcasestr.cpp (revision 71db0c75aadcf003ffe3238005f61d7618a3fead)
1 //===-- Implementation of strcasestr --------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include "src/string/strcasestr.h"
10 
11 #include "src/__support/common.h"
12 #include "src/__support/ctype_utils.h"
13 #include "src/__support/macros/config.h"
14 #include "src/string/memory_utils/inline_strstr.h"
15 
16 namespace LIBC_NAMESPACE_DECL {
17 
18 // TODO: This is a simple brute force implementation. This can be
19 // improved upon using well known string matching algorithms.
20 LLVM_LIBC_FUNCTION(char *, strcasestr,
21                    (const char *haystack, const char *needle)) {
__anon3abebf140102(char a, char b) 22   auto case_cmp = [](char a, char b) {
23     return LIBC_NAMESPACE::internal::tolower(a) -
24            LIBC_NAMESPACE::internal::tolower(b);
25   };
26   return inline_strstr(haystack, needle, case_cmp);
27 }
28 
29 } // namespace LIBC_NAMESPACE_DECL
30