text: /*
   * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions are met:
   *
   * 1. Redistributions of source code must retain the above copyright notice, this
   *    list of conditions and the following disclaimer.
   *
   * 2. Redistributions in binary form must reproduce the above copyright notice,
   *    this list of conditions and the following disclaimer in the documentation
   *    and/or other materials provided with the distribution.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
   * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
   * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
   * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
   * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
   * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
   * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  
  #include <AK/ByteBuffer.h>
  #include <AK/FlyString.h>
  #include <AK/Memory.h>
  #include <AK/String.h>
  #include <AK/StringView.h>
  #include <AK/Vector.h>
  
  namespace AK {
  
  StringView::StringView(const String& string)
      : m_impl(string.impl())
      , m_characters(string.characters())
      , m_length(string.length())
  {
  }
  
  StringView::StringView(const FlyString& string)
      : m_impl(string.impl())
      , m_characters(string.characters())
      , m_length(string.length())
  {
  }
  
  StringView::StringView(const ByteBuffer& buffer)
      : m_characters((const char*)buffer.data())
      , m_length(buffer.size())
  {
  }
  
  Vector<StringView> StringView::split_view(const char separator, bool keep_empty) const
  {
      if (is_empty())
          return {};
  
      Vector<StringView> v;
      size_t substart = 0;
      for (size_t i = 0; i < length(); ++i) {
          char ch = characters_without_null_termination()[i];
          if (ch == separator) {
              size_t sublen = i - substart;
              if (sublen != 0 || keep_empty)
                  v.append(substring_view(substart, sublen));
              substart = i + 1;
          }
      }
      size_t taillen = length() - substart;
      if (taillen != 0 || keep_empty)
          v.append(substring_view(substart, taillen));
      return v;
  }
  
  Vector<StringView> StringView::split_view(const StringView& separator, bool keep_empty) const
  {
      ASSERT(!separator.is_empty());
  
      if (is_empty())
          return {};
  
      StringView view { *this };
  
      Vector<StringView> parts;
  
      auto maybe_separator_index = find_first_of(separator);
      while (maybe_separator_index.has_value()) {
          auto separator_index = maybe_separator_index.value();
          auto part_with_separator = view.substring_view(0, separator_index + separator.length());
          if (keep_empty || separator_index > 0)
              parts.append(part_with_separator.substring_view(0, separator_index));
          view = view.substring_view_starting_after_substring(part_with_separator);
          maybe_separator_index = view.find_first_of(separator);
      }
      if (keep_empty || !view.is_empty())
          parts.append(view);
  
      return parts;
  }
  
  Vector<StringView> StringView::lines(bool consider_cr) const
  {
      if (is_empty())
          return {};
  
      if (!consider_cr)
          return split_view('\n', true);
  
      Vector<StringView> v;
      size_t substart = 0;
      bool last_ch_was_cr = false;
      bool split_view = false;
      for (size_t i = 0; i < length(); ++i) {
          char ch = characters_without_null_termination()[i];
          if (ch == '\n') {
              split_view = true;
              if (last_ch_was_cr) {
                  substart = i + 1;
                  split_view = false;
                  last_ch_was_cr = false;
              }
          }
          if (ch == '\r') {
              split_view = true;
              last_ch_was_cr = true;
          }
          if (split_view) {
              size_t sublen = i - substart;
              v.append(substring_view(substart, sublen));
              substart = i + 1;
          }
          split_view = false;
      }
      size_t taillen = length() - substart;
      if (taillen != 0)
          v.append(substring_view(substart, taillen));
      return v;
  }
  
  bool StringView::starts_with(char ch) const
  {
      if (is_empty())
          return false;
      return ch == characters_without_null_termination()[0];
  }
  
  bool StringView::starts_with(const StringView& str, CaseSensitivity case_sensitivity) const
  {
      return StringUtils::starts_with(*this, str, case_sensitivity);
  }
  
  bool StringView::ends_with(char ch) const
  {
      if (is_empty())
          return false;
      return ch == characters_without_null_termination()[length() - 1];
  }
  
  bool StringView::ends_with(const StringView& str, CaseSensitivity case_sensitivity) const
  {
      return StringUtils::ends_with(*this, str, case_sensitivity);
  }
  
  bool StringView::matches(const StringView& mask, Vector<MaskSpan>& mask_spans, CaseSensitivity case_sensitivity) const
  {
      return StringUtils::matches(*this, mask, case_sensitivity, &mask_spans);
  }
  
  bool StringView::matches(const StringView& mask, CaseSensitivity case_sensitivity) const
  {
      return StringUtils::matches(*this, mask, case_sensitivity);
  }
  
  bool StringView::contains(char needle) const
  {
      for (char current : *this) {
          if (current == needle)
              return true;
      }
      return false;
  }
  
  bool StringView::contains(const StringView& needle, CaseSensitivity case_sensitivity) const
  {
      return StringUtils::contains(*this, needle, case_sensitivity);
  }
  
  bool StringView::equals_ignoring_case(const StringView& other) const
  {
      return StringUtils::equals_ignoring_case(*this, other);
  }
  
  StringView StringView::substring_view(size_t start, size_t length) const
  {
      ASSERT(start + length <= m_length);
      return { m_characters + start, length };
  }
  StringView StringView::substring_view(size_t start) const
  {
      ASSERT(start <= m_length);
      return { m_characters + start, length() - start };
  }
  
  StringView StringView::substring_view_starting_from_substring(const StringView& substring) const
  {
      const char* remaining_characters = substring.characters_without_null_termination();
      ASSERT(remaining_characters >= m_characters);
      ASSERT(remaining_characters <= m_characters + m_length);
      size_t remaining_length = m_length - (remaining_characters - m_characters);
      return { remaining_characters, remaining_length };
  }
  
  StringView StringView::substring_view_starting_after_substring(const StringView& substring) const
  {
      const char* remaining_characters = substring.characters_without_null_termination() + substring.length();
      ASSERT(remaining_characters >= m_characters);
      ASSERT(remaining_characters <= m_characters + m_length);
      size_t remaining_length = m_length - (remaining_characters - m_characters);
      return { remaining_characters, remaining_length };
  }
  
  template<typename T>
  Optional<T> StringView::to_int() const
  {
      return StringUtils::convert_to_int<T>(*this);
  }
  
  template Optional<i8> StringView::to_int() const;
  template Optional<i16> StringView::to_int() const;
  template Optional<i32> StringView::to_int() const;
  template Optional<i64> StringView::to_int() const;
  
  template<typename T>
  Optional<T> StringView::to_uint() const
  {
      return StringUtils::convert_to_uint<T>(*this);
  }
  
  template Optional<u8> StringView::to_uint() const;
  template Optional<u16> StringView::to_uint() const;
  template Optional<u32> StringView::to_uint() const;
  template Optional<u64> StringView::to_uint() const;
  template Optional<long> StringView::to_uint() const;
  template Optional<long long> StringView::to_uint() const;
  
  unsigned StringView::hash() const
  {
      if (is_empty())
          return 0;
      if (m_impl)
          return m_impl->hash();
      return string_hash(characters_without_null_termination(), length());
  }
  
  bool StringView::operator==(const String& string) const
  {
      if (string.is_null())
          return !m_characters;
      if (!m_characters)
          return false;
      if (m_length != string.length())
          return false;
      if (m_characters == string.characters())
          return true;
      return !__builtin_memcmp(m_characters, string.characters(), m_length);
  }
  
  Optional<size_t> StringView::find_first_of(char c) const
  {
      for (size_t pos = 0; pos < m_length; ++pos) {
          if (m_characters[pos] == c)
              return pos;
      }
      return {};
  }
  
  Optional<size_t> StringView::find_first_of(const StringView& view) const
  {
      for (size_t pos = 0; pos < m_length; ++pos) {
          char c = m_characters[pos];
          for (char view_char : view) {
              if (c == view_char)
                  return pos;
          }
      }
      return {};
  }
  
  Optional<size_t> StringView::find_last_of(char c) const
  {
      for (size_t pos = m_length; --pos > 0;) {
          if (m_characters[pos] == c)
              return pos;
      }
      return {};
  }
  
  Optional<size_t> StringView::find_last_of(const StringView& view) const
  {
      for (size_t pos = m_length - 1; --pos > 0;) {
          char c = m_characters[pos];
          for (char view_char : view) {
              if (c == view_char)
                  return pos;
          }
      }
      return {};
  }
  
  String StringView::to_string() const { return String { *this }; }
  
  }
  