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/* Copyright 2014 MongoDB Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* As a special exception, the copyright holders give permission to link the
* code of portions of this program with the OpenSSL library under certain
* conditions as described in each individual source file and distribute
* linked combinations including the program with the OpenSSL library. You
* must comply with the GNU Affero General Public License in all respects
* for all of the code used other than as permitted herein. If you modify
* file(s) with this exception, you may extend this exception to your
* version of the file(s), but you are not obligated to do so. If you do not
* wish to do so, delete this exception statement from your version. If you
* delete this exception statement from all source files in the program,
* then also delete it in the license file.
*/
#pragma once
#include <cstring>
#include <type_traits>
#include "mongo/config.h"
#include "mongo/base/data_type.h"
namespace mongo {
class ConstDataView {
public:
typedef const char* bytes_type;
ConstDataView(bytes_type bytes) : _bytes(bytes) {}
bytes_type view(std::size_t offset = 0) const {
return _bytes + offset;
}
template <typename T>
const ConstDataView& read(T* t, size_t offset = 0) const {
DataType::unsafeLoad(t, view(offset), nullptr);
return *this;
}
template <typename T>
T read(std::size_t offset = 0) const {
T t(DataType::defaultConstruct<T>());
read(&t, offset);
return t;
}
private:
bytes_type _bytes;
};
class DataView : public ConstDataView {
public:
typedef char* bytes_type;
DataView(bytes_type bytes) : ConstDataView(bytes) {}
bytes_type view(std::size_t offset = 0) const {
// It is safe to cast away const here since the pointer stored in our base class was
// originally non-const by way of our constructor.
return const_cast<bytes_type>(ConstDataView::view(offset));
}
template <typename T>
DataView& write(const T& value, std::size_t offset = 0) {
DataType::unsafeStore(value, view(offset), nullptr);
return *this;
}
};
} // namespace mongo
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