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/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil -*- */
/*
* Copyright (c) 2013, Regents of the University of California
*
* BSD license, See the LICENSE file for more information
*
* Author: Alexander Afanasyev <alexander.afanasyev@ucla.edu>
*/
#ifndef NDN_BUFFER_HPP
#define NDN_BUFFER_HPP
#include "../common.hpp"
namespace ndn {
class Buffer;
typedef ptr_lib::shared_ptr<const Buffer> ConstBufferPtr;
typedef ptr_lib::shared_ptr<Buffer> BufferPtr;
/**
* @brief Class representing a general-use automatically managed/resized buffer
*
* In most respect, Buffer class is equivalent to std::vector<uint8_t> and is in fact
* uses it as a base class. In addition to that, it provides buf() and buf<T>() helper
* method for easier access to the underlying data (buf<T>() casts pointer to the requested class)
*/
class Buffer : public std::vector<uint8_t>
{
public:
/**
* @brief Creates an empty buffer
*/
Buffer()
{
}
/**
* @brief Creates a buffer with pre-allocated size
* @param size size of the buffer to be allocated
*/
explicit
Buffer(size_t size)
: std::vector<uint8_t>(size, 0)
{
}
/**
* @brief Create a buffer by copying the supplied data from a const buffer
* @param buf const pointer to buffer
* @param length length of the buffer to copy
*/
Buffer(const void* buf, size_t length)
: std::vector<uint8_t>(reinterpret_cast<const uint8_t*>(buf),
reinterpret_cast<const uint8_t*>(buf) + length)
{
}
/**
* @brief Create a buffer by copying the supplied data using iterator interface
*
* Note that the supplied iterators must be compatible with std::vector<uint8_t> interface
*
* @param first iterator to a first element to copy
* @param last iterator to an element immediately following the last element to copy
*/
template <class InputIterator>
Buffer(InputIterator first, InputIterator last)
: std::vector<uint8_t>(first, last)
{
}
/**
* @brief Get pointer to the first byte of the buffer
*/
uint8_t*
get()
{
return &front();
}
/**
* @brief Get pointer to the first byte of the buffer (alternative version)
*/
uint8_t*
buf()
{
return &front();
}
/**
* @brief Get pointer to the first byte of the buffer and cast
* it (reinterpret_cast) to the requested type T
*/
template<class T>
T*
get()
{
return reinterpret_cast<T*>(&front());
}
/**
* @brief Get pointer to the first byte of the buffer (alternative version)
*/
const uint8_t*
buf() const
{
return &front();
}
/**
* @brief Get const pointer to the first byte of the buffer
*/
const uint8_t*
get() const
{
return &front();
}
/**
* @brief Get const pointer to the first byte of the buffer and cast
* it (reinterpret_cast) to the requested type T
*/
template<class T>
const T*
get() const
{
return reinterpret_cast<const T*>(&front());
}
};
/// @cond include_hidden
namespace iostreams
{
class buffer_append_device
{
public:
typedef char char_type;
typedef boost::iostreams::sink_tag category;
buffer_append_device(Buffer& container)
: m_container(container)
{
}
std::streamsize
write(const char_type* s, std::streamsize n)
{
std::copy(s, s+n, std::back_inserter(m_container));
return n;
}
protected:
Buffer& m_container;
};
} // iostreams
/// @endcond
/**
* Class implementing interface similar to ostringstream, but to construct ndn::Buffer
*
* The benefit of using stream interface is that it provides automatic buffering of
* written data and eliminates (or reduces) overhead of resizing the underlying buffer
* when writing small pieces of data.
*
* Usage example:
* @code
* OBufferStream obuf;
* obuf.put(0);
* obuf.write(another_buffer, another_buffer_size);
* ptr_lib::shared_ptr<Buffer> buf = obuf.get();
* @endcode
*/
struct OBufferStream : public boost::iostreams::stream<iostreams::buffer_append_device>
{
/**
* Default constructor
*/
OBufferStream()
: m_buffer(ptr_lib::make_shared<Buffer>())
, m_device(*m_buffer)
{
open(m_device);
}
/**
* Flush written data to the stream and return shared pointer to the underlying buffer
*/
ptr_lib::shared_ptr<Buffer>
buf()
{
flush();
return m_buffer;
}
private:
BufferPtr m_buffer;
iostreams::buffer_append_device m_device;
};
} // ndn
#endif // NDN_BUFFER_HPP