llvm/llvm/include/llvm/ADT/CachedHashString.h

//===- llvm/ADT/CachedHashString.h - Prehashed string/StringRef -*- C++ -*-===//
//
// 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
//
//===----------------------------------------------------------------------===//
///
/// \file
/// This file defines CachedHashString and CachedHashStringRef.  These are
/// owning and not-owning string types that store their hash in addition to
/// their string data.
///
/// Unlike std::string, CachedHashString can be used in DenseSet/DenseMap
/// (because, unlike std::string, CachedHashString lets us have empty and
/// tombstone values).
///
//===----------------------------------------------------------------------===//

#ifndef LLVM_ADT_CACHEDHASHSTRING_H
#define LLVM_ADT_CACHEDHASHSTRING_H

#include "llvm/ADT/DenseMapInfo.h"
#include "llvm/ADT/StringRef.h"

namespace llvm {

/// A container which contains a StringRef plus a precomputed hash.
class CachedHashStringRef { … };

template <> struct DenseMapInfo<CachedHashStringRef> { … };

/// A container which contains a string, which it owns, plus a precomputed hash.
///
/// We do not null-terminate the string.
class CachedHashString { … };

template <> struct DenseMapInfo<CachedHashString> { … };

} // namespace llvm

#endif