| //===-- Implementation of wcsstr ------------------------------------------===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "src/wchar/wcsstr.h" |
| |
| #include "hdr/types/size_t.h" |
| #include "hdr/types/wchar_t.h" |
| #include "src/__support/common.h" |
| #include "src/__support/macros/config.h" |
| #include "src/string/string_utils.h" |
| |
| namespace LIBC_NAMESPACE_DECL { |
| |
| LLVM_LIBC_FUNCTION(const wchar_t *, wcsstr, |
| (const wchar_t *s1, const wchar_t *s2)) { |
| size_t s1_len = internal::string_length(s1); |
| size_t s2_len = internal::string_length(s2); |
| if (s2_len == 0) |
| return s1; |
| if (s2_len > s1_len) |
| return nullptr; |
| for (size_t i = 0; i <= (s1_len - s2_len); ++i) { |
| size_t j = 0; |
| // j will increment until the characters don't match or end of string. |
| for (; j < s2_len && s1[i + j] == s2[j]; ++j) |
| ; |
| if (j == s2_len) |
| return (s1 + i); |
| } |
| return nullptr; |
| } |
| |
| } // namespace LIBC_NAMESPACE_DECL |