chromium/components/zucchini/typed_value.h

// Copyright 2017 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef COMPONENTS_ZUCCHINI_TYPED_VALUE_H_
#define COMPONENTS_ZUCCHINI_TYPED_VALUE_H_

#include <ostream>

namespace zucchini {

// Strong typed values, with compare and convert functions for underlying data.
// Typically one would use strongly typed enums for this. However, for Zucchini,
// the number of bytes is not fixed, and must be represented as an integer for
// iteration.
// |Tag| is a type tag used to uniquely identify TypedValue.
// |T| is an integral type used to hold values.
// Example:
//    struct Foo : TypedValue<Foo, int> {
//      using Foo::TypedValue::TypedValue; // inheriting constructor.
//    };
// Foo will be used to hold values of type |int|, but with a distinct type from
// any other TypedValue.
template <class Tag, class T>
class TypedValue { … };

template <class Tag, class T>
std::ostream& operator<<(std::ostream& os, const TypedValue<Tag, T>& tag) { … }

}  // namespace zucchini

#endif  // COMPONENTS_ZUCCHINI_TYPED_VALUE_H_