libc/src/wchar/wcstok.cpp

//===-- Implementation of wcstok ------------------------------------------===//
//
// 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/wcstok.h"

#include "hdr/types/wchar_t.h"
#include "src/__support/common.h"
#include "wchar_utils.h"

namespace LIBC_NAMESPACE_DECL {

LLVM_LIBC_FUNCTION(wchar_t *, wcstok,
                   (wchar_t *__restrict str, const wchar_t *__restrict delims,
                    wchar_t **__restrict context)) {
  if (str == nullptr) {
    if (*context == nullptr)
      return nullptr;

    str = *context;
  }

  wchar_t *tok_start = str;
  while (*tok_start != L'\0' && internal::wcschr(delims, *tok_start))
    ++tok_start;
  if (*tok_start == L'\0') {
    *context = nullptr;
    return nullptr;
  }

  wchar_t *tok_end = tok_start;
  while (*tok_end != L'\0' && !internal::wcschr(delims, *tok_end))
    ++tok_end;

  if (*tok_end == L'\0') {
    *context = nullptr;
  } else {
    *tok_end = L'\0';
    *context = tok_end + 1;
  }
  return tok_start;
}

} // namespace LIBC_NAMESPACE_DECL