StringView.h

/*
 * Copyright (c) 2008-2014, Pedigree Developers
 *
 * Please see the CONTRIB file in the root of the source tree for a full
 * list of contributors.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
 
#ifndef KERNEL_UTILITIES_STRINGVIEW_H
#define KERNEL_UTILITIES_STRINGVIEW_H
 
#define HASH_STRINGVIEWS_BY_DEFAULT false
 
#include "pedigree/kernel/compiler.h"
#include "pedigree/kernel/processor/types.h"
#include "pedigree/kernel/utilities/template.h"  // IWYU pragma: keep
 
class String;
 
class EXPORTED_PUBLIC StringView {
  friend class String;
 
 public:
  StringView();
  explicit StringView(const char* s);
  StringView(const char* s, size_t length);
  StringView(const StringView& other);
  explicit StringView(const String& other);
  virtual ~StringView();
 
  StringView& operator=(const StringView& s);
 
  bool operator==(const char* s) const;
  bool operator==(const String& s) const;
  bool operator==(const StringView& s) const;
 
  bool compare(const char* s, size_t length) const;
 
  size_t length() const;
 
  StringView substring(size_t start, size_t end, bool hashed = HASH_STRINGVIEWS_BY_DEFAULT) const;
 
  String toString() const;
 
  char operator[](size_t index) const;
 
  size_t nextCharacter(size_t i) const;
  size_t prevCharacter(size_t i) const;
 
  uint32_t hash() const;
  uint32_t hash();
 
  const char* str() const;
 
  void setHashingEnable(bool enabled);
 
 private:
  bool compareHash(const StringView& other) const;
  bool compareHash(const String& other) const;
 
  uint32_t computeHash() const;
 
  // String::view() can set m_Hash to avoid recalculating.
  StringView(const char* s, size_t length, uint32_t hash, bool hashingEnabled);
 
  const char* m_String;
  size_t m_Length;
  uint32_t m_Hash;
  bool m_HashingEnabled;
 
 protected:
  virtual bool defaultHashingEnabled() const;
};
 
class EXPORTED_PUBLIC HashedStringView : public StringView {
 public:
  HashedStringView() = default;
  explicit HashedStringView(const char* s);
  HashedStringView(const char* s, size_t length);
  HashedStringView(const StringView& other);
  HashedStringView(const HashedStringView& other);
  HashedStringView(const String& other);
 
 private:
  bool defaultHashingEnabled() const override;
};
 
#endif  // KERNEL_UTILITIES_STRINGVIEW_H