/*************************************************************************
 *
 * Copyright 2016 Realm Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 **************************************************************************/

#ifndef REALM_OWNED_DATA_HPP
#define REALM_OWNED_DATA_HPP

#include <realm/util/assert.hpp>

#include <cstring>
#include <memory>

namespace realm {

/// A chunk of owned data.
class OwnedData {
public:
    /// Construct a null reference.
    OwnedData() noexcept
    {
    }

    /// If \a data_to_copy is 'null', \a data_size must be zero.
    OwnedData(const char* data_to_copy, size_t data_size)
        : m_size(data_size)
    {
        REALM_ASSERT_DEBUG(data_to_copy || data_size == 0);
        if (data_to_copy) {
            m_data = std::unique_ptr<char[]>(new char[data_size]);
            memcpy(m_data.get(), data_to_copy, data_size);
        }
    }

    /// If \a unique_data is 'null', \a data_size must be zero.
    OwnedData(std::unique_ptr<char[]> unique_data, size_t data_size) noexcept
        : m_data(std::move(unique_data))
        , m_size(data_size)
    {
        REALM_ASSERT_DEBUG(m_data || m_size == 0);
    }

    OwnedData(const OwnedData& other)
        : OwnedData(other.m_data.get(), other.m_size)
    {
    }
    OwnedData& operator=(const OwnedData& other);

    OwnedData(OwnedData&&) = default;
    OwnedData& operator=(OwnedData&&) = default;

    const char* data() const
    {
        return m_data.get();
    }
    size_t size() const
    {
        return m_size;
    }

private:
    std::unique_ptr<char[]> m_data;
    size_t m_size = 0;
};

inline OwnedData& OwnedData::operator=(const OwnedData& other)
{
    if (this != &other) {
        if (other.m_data) {
            m_data = std::unique_ptr<char[]>(new char[other.m_size]);
            memcpy(m_data.get(), other.m_data.get(), other.m_size);
        }
        else {
            m_data = nullptr;
        }
        m_size = other.m_size;
    }
    return *this;
}

} // namespace realm

#endif // REALM_OWNED_DATA_HPP