libc/src/string/strcasestr.cpp

   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/string/memory_utils/inline_strstr.h"
  14
  15 namespace __llvm_libc {
  16
  17 // TODO: This is a simple brute force implementation. This can be
  18 // improved upon using well known string matching algorithms.
  19 LLVM_LIBC_FUNCTION(char *, strcasestr,
  20                    (const char *haystack, const char *needle)) {
  21   auto case_cmp = [](char a, char b) {
  22     return __llvm_libc::internal::tolower(a) -
  23            __llvm_libc::internal::tolower(b);
  24   };
  25   return inline_strstr(haystack, needle, case_cmp);
  26 }
  27
  28 } // namespace __llvm_libc