buffer_view.h

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/*******************************************************************************
 * Copyright (c) 2017-2020 Frank Pagliughi <fpagliughi@mindspring.com>
 *
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v2.0
 * and Eclipse Distribution License v1.0 which accompany this distribution.
 *
 * The Eclipse Public License is available at
 *    http://www.eclipse.org/legal/epl-v20.html
 * and the Eclipse Distribution License is available at
 *   http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * Contributors:
 *    Frank Pagliughi - initial implementation and documentation
 *******************************************************************************/
 
#ifndef __mqtt_buffer_view_h
#define __mqtt_buffer_view_h
 
#include <iostream>
 
#include "mqtt/types.h"
 
namespace mqtt {


template <typename T>
class buffer_view
{
public:
    using value_type = T;
    using size_type = size_t;
 
private:
    const value_type* data_;
    size_type sz_;
 
public:
    buffer_view(const value_type* data, size_type n) : data_(data), sz_(n) {}
    buffer_view(const std::basic_string<value_type>& str)
        : data_(str.data()), sz_(str.size()) {}

    const value_type* data() const { return data_; }
    size_type size() const { return sz_; }
    size_type length() const { return sz_; }
    const value_type& operator[](size_t i) const { return data_[i]; }
    std::basic_string<value_type> str() const {
        return std::basic_string<value_type>(data_, sz_);
    }

    string to_string() const {
        static_assert(
            sizeof(char) == sizeof(T), "can only get string for char or byte buffers"
        );
        return string(reinterpret_cast<const char*>(data_), sz_);
    }
};

template <typename T>
std::ostream& operator<<(std::ostream& os, const buffer_view<T>& buf) {
    if (buf.size() > 0)
        os.write(buf.data(), sizeof(T) * buf.size());
    return os;
}

using string_view = buffer_view<char>;

using binary_view = buffer_view<char>;

// end namespace mqtt
}  // namespace mqtt
 
#endif  // __mqtt_buffer_view_h