deluge/include/libtorrent/asio/buffer.hpp

640 lines
18 KiB
C++

//
// buffer.hpp
// ~~~~~~~~~~
//
// Copyright (c) 2003-2006 Christopher M. Kohlhoff (chris at kohlhoff dot com)
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
#ifndef ASIO_BUFFER_HPP
#define ASIO_BUFFER_HPP
#if defined(_MSC_VER) && (_MSC_VER >= 1200)
# pragma once
#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
#include "asio/detail/push_options.hpp"
#include "asio/detail/push_options.hpp"
#include <cstddef>
#include <boost/config.hpp>
#include <boost/array.hpp>
#include <boost/type_traits/is_const.hpp>
#include <string>
#include <vector>
#include "asio/detail/pop_options.hpp"
namespace asio {
class mutable_buffer;
class const_buffer;
namespace detail {
void* buffer_cast_helper(const mutable_buffer&);
const void* buffer_cast_helper(const const_buffer&);
std::size_t buffer_size_helper(const mutable_buffer&);
std::size_t buffer_size_helper(const const_buffer&);
} // namespace detail
/// Holds a buffer that can be modified.
/**
* The mutable_buffer class provides a safe representation of a buffer that can
* be modified. It does not own the underlying data, and so is cheap to copy or
* assign.
*/
class mutable_buffer
{
public:
/// Construct an empty buffer.
mutable_buffer()
: data_(0),
size_(0)
{
}
/// Construct a buffer to represent a given memory range.
mutable_buffer(void* data, std::size_t size)
: data_(data),
size_(size)
{
}
private:
friend void* asio::detail::buffer_cast_helper(
const mutable_buffer& b);
friend std::size_t asio::detail::buffer_size_helper(
const mutable_buffer& b);
void* data_;
std::size_t size_;
};
namespace detail {
inline void* buffer_cast_helper(const mutable_buffer& b)
{
return b.data_;
}
inline std::size_t buffer_size_helper(const mutable_buffer& b)
{
return b.size_;
}
} // namespace detail
/// Cast a non-modifiable buffer to a specified pointer to POD type.
/**
* @relates mutable_buffer
*/
template <typename Pointer_To_Pod_Type>
inline Pointer_To_Pod_Type buffer_cast(const mutable_buffer& b)
{
return static_cast<Pointer_To_Pod_Type>(detail::buffer_cast_helper(b));
}
/// Get the number of bytes in a non-modifiable buffer.
/**
* @relates mutable_buffer
*/
inline std::size_t buffer_size(const mutable_buffer& b)
{
return detail::buffer_size_helper(b);
}
/// Create a new modifiable buffer that is offset from the start of another.
/**
* @relates mutable_buffer
*/
inline mutable_buffer operator+(const mutable_buffer& b, std::size_t start)
{
if (start > buffer_size(b))
return mutable_buffer();
char* new_data = buffer_cast<char*>(b) + start;
std::size_t new_size = buffer_size(b) - start;
return mutable_buffer(new_data, new_size);
}
/// Create a new modifiable buffer that is offset from the start of another.
/**
* @relates mutable_buffer
*/
inline mutable_buffer operator+(std::size_t start, const mutable_buffer& b)
{
if (start > buffer_size(b))
return mutable_buffer();
char* new_data = buffer_cast<char*>(b) + start;
std::size_t new_size = buffer_size(b) - start;
return mutable_buffer(new_data, new_size);
}
/// Adapts a single modifiable buffer so that it meets the requirements of the
/// Mutable_Buffers concept.
class mutable_buffer_container_1
: public mutable_buffer
{
public:
/// The type for each element in the list of buffers.
typedef mutable_buffer value_type;
/// A random-access iterator type that may be used to read elements.
typedef const mutable_buffer* const_iterator;
/// Construct to represent a single modifiable buffer.
explicit mutable_buffer_container_1(const mutable_buffer& b)
: mutable_buffer(b)
{
}
/// Get a random-access iterator to the first element.
const_iterator begin() const
{
return this;
}
/// Get a random-access iterator for one past the last element.
const_iterator end() const
{
return begin() + 1;
}
};
/// Holds a buffer that cannot be modified.
/**
* The const_buffer class provides a safe representation of a buffer that cannot
* be modified. It does not own the underlying data, and so is cheap to copy or
* assign.
*/
class const_buffer
{
public:
/// Construct an empty buffer.
const_buffer()
: data_(0),
size_(0)
{
}
/// Construct a buffer to represent a given memory range.
const_buffer(const void* data, std::size_t size)
: data_(data),
size_(size)
{
}
/// Construct a non-modifiable buffer from a modifiable one.
const_buffer(const mutable_buffer& b)
: data_(asio::detail::buffer_cast_helper(b)),
size_(asio::detail::buffer_size_helper(b))
{
}
private:
friend const void* asio::detail::buffer_cast_helper(
const const_buffer& b);
friend std::size_t asio::detail::buffer_size_helper(
const const_buffer& b);
const void* data_;
std::size_t size_;
};
namespace detail {
inline const void* buffer_cast_helper(const const_buffer& b)
{
return b.data_;
}
inline std::size_t buffer_size_helper(const const_buffer& b)
{
return b.size_;
}
} // namespace detail
/// Cast a non-modifiable buffer to a specified pointer to POD type.
/**
* @relates const_buffer
*/
template <typename Pointer_To_Pod_Type>
inline Pointer_To_Pod_Type buffer_cast(const const_buffer& b)
{
return static_cast<Pointer_To_Pod_Type>(detail::buffer_cast_helper(b));
}
/// Get the number of bytes in a non-modifiable buffer.
/**
* @relates const_buffer
*/
inline std::size_t buffer_size(const const_buffer& b)
{
return detail::buffer_size_helper(b);
}
/// Create a new non-modifiable buffer that is offset from the start of another.
/**
* @relates const_buffer
*/
inline const_buffer operator+(const const_buffer& b, std::size_t start)
{
if (start > buffer_size(b))
return const_buffer();
const char* new_data = buffer_cast<const char*>(b) + start;
std::size_t new_size = buffer_size(b) - start;
return const_buffer(new_data, new_size);
}
/// Create a new non-modifiable buffer that is offset from the start of another.
/**
* @relates const_buffer
*/
inline const_buffer operator+(std::size_t start, const const_buffer& b)
{
if (start > buffer_size(b))
return const_buffer();
const char* new_data = buffer_cast<const char*>(b) + start;
std::size_t new_size = buffer_size(b) - start;
return const_buffer(new_data, new_size);
}
/// Adapts a single non-modifiable buffer so that it meets the requirements of
/// the Const_Buffers concept.
class const_buffer_container_1
: public const_buffer
{
public:
/// The type for each element in the list of buffers.
typedef const_buffer value_type;
/// A random-access iterator type that may be used to read elements.
typedef const const_buffer* const_iterator;
/// Construct to represent a single non-modifiable buffer.
explicit const_buffer_container_1(const const_buffer& b)
: const_buffer(b)
{
}
/// Get a random-access iterator to the first element.
const_iterator begin() const
{
return this;
}
/// Get a random-access iterator for one past the last element.
const_iterator end() const
{
return begin() + 1;
}
};
/** @defgroup buffer asio::buffer
*
* @brief The asio::buffer function is used to create a buffer object to
* represent raw memory, an array of POD elements, or a vector of POD elements.
*
* The simplest use case involves reading or writing a single buffer of a
* specified size:
*
* @code sock.write(asio::buffer(data, size)); @endcode
*
* In the above example, the return value of asio::buffer meets the
* requirements of the Const_Buffers concept so that it may be directly passed
* to the socket's write function. A buffer created for modifiable memory also
* meets the requirements of the Mutable_Buffers concept.
*
* An individual buffer may be created from a builtin array, std::vector or
* boost::array of POD elements. This helps prevent buffer overruns by
* automatically determining the size of the buffer:
*
* @code char d1[128];
* size_t bytes_transferred = sock.read(asio::buffer(d1));
*
* std::vector<char> d2(128);
* bytes_transferred = sock.read(asio::buffer(d2));
*
* boost::array<char, 128> d3;
* bytes_transferred = sock.read(asio::buffer(d3)); @endcode
*
* To read or write using multiple buffers (i.e. scatter-gather I/O), multiple
* buffer objects may be assigned into a container that supports the
* Mutable_Buffers (for read) or Const_Buffers (for write) concepts:
*
* @code
* char d1[128];
* std::vector<char> d2(128);
* boost::array<char, 128> d3;
*
* boost::array<mutable_buffer, 3> bufs1 = {
* asio::buffer(d1),
* asio::buffer(d2),
* asio::buffer(d3) };
* bytes_transferred = sock.read(bufs1);
*
* std::vector<const_buffer> bufs2;
* bufs2.push_back(asio::buffer(d1));
* bufs2.push_back(asio::buffer(d2));
* bufs2.push_back(asio::buffer(d3));
* bytes_transferred = sock.write(bufs2); @endcode
*/
/*@{*/
/// Create a new modifiable buffer from an existing buffer.
inline mutable_buffer_container_1 buffer(const mutable_buffer& b)
{
return mutable_buffer_container_1(b);
}
/// Create a new modifiable buffer from an existing buffer.
inline mutable_buffer_container_1 buffer(const mutable_buffer& b,
std::size_t max_size_in_bytes)
{
return mutable_buffer_container_1(
mutable_buffer(buffer_cast<void*>(b),
buffer_size(b) < max_size_in_bytes
? buffer_size(b) : max_size_in_bytes));
}
/// Create a new non-modifiable buffer from an existing buffer.
inline const_buffer_container_1 buffer(const const_buffer& b)
{
return const_buffer_container_1(b);
}
/// Create a new non-modifiable buffer from an existing buffer.
inline const_buffer_container_1 buffer(const const_buffer& b,
std::size_t max_size_in_bytes)
{
return const_buffer_container_1(
const_buffer(buffer_cast<const void*>(b),
buffer_size(b) < max_size_in_bytes
? buffer_size(b) : max_size_in_bytes));
}
/// Create a new modifiable buffer that represents the given memory range.
inline mutable_buffer_container_1 buffer(void* data, std::size_t size_in_bytes)
{
return mutable_buffer_container_1(mutable_buffer(data, size_in_bytes));
}
/// Create a new non-modifiable buffer that represents the given memory range.
inline const_buffer_container_1 buffer(const void* data,
std::size_t size_in_bytes)
{
return const_buffer_container_1(const_buffer(data, size_in_bytes));
}
/// Create a new modifiable buffer that represents the given POD array.
template <typename Pod_Type, std::size_t N>
inline mutable_buffer_container_1 buffer(Pod_Type (&data)[N])
{
return mutable_buffer_container_1(mutable_buffer(data, N * sizeof(Pod_Type)));
}
/// Create a new modifiable buffer that represents the given POD array.
template <typename Pod_Type, std::size_t N>
inline mutable_buffer_container_1 buffer(Pod_Type (&data)[N],
std::size_t max_size_in_bytes)
{
return mutable_buffer_container_1(
mutable_buffer(data,
N * sizeof(Pod_Type) < max_size_in_bytes
? N * sizeof(Pod_Type) : max_size_in_bytes));
}
/// Create a new non-modifiable buffer that represents the given POD array.
template <typename Pod_Type, std::size_t N>
inline const_buffer_container_1 buffer(const Pod_Type (&data)[N])
{
return const_buffer_container_1(const_buffer(data, N * sizeof(Pod_Type)));
}
/// Create a new non-modifiable buffer that represents the given POD array.
template <typename Pod_Type, std::size_t N>
inline const_buffer_container_1 buffer(const Pod_Type (&data)[N],
std::size_t max_size_in_bytes)
{
return const_buffer_container_1(
const_buffer(data,
N * sizeof(Pod_Type) < max_size_in_bytes
? N * sizeof(Pod_Type) : max_size_in_bytes));
}
#if BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x564))
// Borland C++ thinks the overloads:
//
// unspecified buffer(boost::array<Pod_Type, N>& array ...);
//
// and
//
// unspecified buffer(boost::array<const Pod_Type, N>& array ...);
//
// are ambiguous. This will be worked around by using a buffer_types traits
// class that contains typedefs for the appropriate buffer and container
// classes, based on whether Pod_Type is const or non-const.
namespace detail {
template <bool IsConst>
struct buffer_types_base;
template <>
struct buffer_types_base<false>
{
typedef mutable_buffer buffer_type;
typedef mutable_buffer_container_1 container_type;
};
template <>
struct buffer_types_base<true>
{
typedef const_buffer buffer_type;
typedef const_buffer_container_1 container_type;
};
template <typename Pod_Type>
struct buffer_types
: public buffer_types_base<boost::is_const<Pod_Type>::value>
{
};
} // namespace detail
template <typename Pod_Type, std::size_t N>
inline typename detail::buffer_types<Pod_Type>::container_type
buffer(boost::array<Pod_Type, N>& data)
{
typedef typename asio::detail::buffer_types<Pod_Type>::buffer_type
buffer_type;
typedef typename asio::detail::buffer_types<Pod_Type>::container_type
container_type;
return container_type(
buffer_type(data.c_array(), data.size() * sizeof(Pod_Type)));
}
template <typename Pod_Type, std::size_t N>
inline typename detail::buffer_types<Pod_Type>::container_type
buffer(boost::array<Pod_Type, N>& data, std::size_t max_size_in_bytes)
{
typedef typename asio::detail::buffer_types<Pod_Type>::buffer_type
buffer_type;
typedef typename asio::detail::buffer_types<Pod_Type>::container_type
container_type;
return container_type(
buffer_type(data.c_array(),
data.size() * sizeof(Pod_Type) < max_size_in_bytes
? data.size() * sizeof(Pod_Type) : max_size_in_bytes));
}
#else // BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x564))
/// Create a new modifiable buffer that represents the given POD array.
template <typename Pod_Type, std::size_t N>
inline mutable_buffer_container_1 buffer(boost::array<Pod_Type, N>& data)
{
return mutable_buffer_container_1(
mutable_buffer(data.c_array(), data.size() * sizeof(Pod_Type)));
}
/// Create a new modifiable buffer that represents the given POD array.
template <typename Pod_Type, std::size_t N>
inline mutable_buffer_container_1 buffer(boost::array<Pod_Type, N>& data,
std::size_t max_size_in_bytes)
{
return mutable_buffer_container_1(
mutable_buffer(data.c_array(),
data.size() * sizeof(Pod_Type) < max_size_in_bytes
? data.size() * sizeof(Pod_Type) : max_size_in_bytes));
}
/// Create a new non-modifiable buffer that represents the given POD array.
template <typename Pod_Type, std::size_t N>
inline const_buffer_container_1 buffer(boost::array<const Pod_Type, N>& data)
{
return const_buffer_container_1(
const_buffer(data.data(), data.size() * sizeof(Pod_Type)));
}
/// Create a new non-modifiable buffer that represents the given POD array.
template <typename Pod_Type, std::size_t N>
inline const_buffer_container_1 buffer(boost::array<const Pod_Type, N>& data,
std::size_t max_size_in_bytes)
{
return const_buffer_container_1(
const_buffer(data.data(),
data.size() * sizeof(Pod_Type) < max_size_in_bytes
? data.size() * sizeof(Pod_Type) : max_size_in_bytes));
}
#endif // BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x564))
/// Create a new non-modifiable buffer that represents the given POD array.
template <typename Pod_Type, std::size_t N>
inline const_buffer_container_1 buffer(const boost::array<Pod_Type, N>& data)
{
return const_buffer_container_1(
const_buffer(data.data(), data.size() * sizeof(Pod_Type)));
}
/// Create a new non-modifiable buffer that represents the given POD array.
template <typename Pod_Type, std::size_t N>
inline const_buffer_container_1 buffer(const boost::array<Pod_Type, N>& data,
std::size_t max_size_in_bytes)
{
return const_buffer_container_1(
const_buffer(data.data(),
data.size() * sizeof(Pod_Type) < max_size_in_bytes
? data.size() * sizeof(Pod_Type) : max_size_in_bytes));
}
/// Create a new modifiable buffer that represents the given POD vector.
/**
* @note The buffer is invalidated by any vector operation that would also
* invalidate iterators.
*/
template <typename Pod_Type, typename Allocator>
inline mutable_buffer_container_1 buffer(std::vector<Pod_Type, Allocator>& data)
{
return mutable_buffer_container_1(
mutable_buffer(&data[0], data.size() * sizeof(Pod_Type)));
}
/// Create a new modifiable buffer that represents the given POD vector.
/**
* @note The buffer is invalidated by any vector operation that would also
* invalidate iterators.
*/
template <typename Pod_Type, typename Allocator>
inline mutable_buffer_container_1 buffer(std::vector<Pod_Type, Allocator>& data,
std::size_t max_size_in_bytes)
{
return mutable_buffer_container_1(
mutable_buffer(&data[0],
data.size() * sizeof(Pod_Type) < max_size_in_bytes
? data.size() * sizeof(Pod_Type) : max_size_in_bytes));
}
/// Create a new non-modifiable buffer that represents the given POD vector.
/**
* @note The buffer is invalidated by any vector operation that would also
* invalidate iterators.
*/
template <typename Pod_Type, typename Allocator>
inline const_buffer_container_1 buffer(
const std::vector<Pod_Type, Allocator>& data)
{
return const_buffer_container_1(
const_buffer(&data[0], data.size() * sizeof(Pod_Type)));
}
/// Create a new non-modifiable buffer that represents the given POD vector.
/**
* @note The buffer is invalidated by any vector operation that would also
* invalidate iterators.
*/
template <typename Pod_Type, typename Allocator>
inline const_buffer_container_1 buffer(
const std::vector<Pod_Type, Allocator>& data, std::size_t max_size_in_bytes)
{
return const_buffer_container_1(
const_buffer(&data[0],
data.size() * sizeof(Pod_Type) < max_size_in_bytes
? data.size() * sizeof(Pod_Type) : max_size_in_bytes));
}
/// Create a new non-modifiable buffer that represents the given string.
/**
* @note The buffer is invalidated by any non-const operation called on the
* given string object.
*/
inline const_buffer_container_1 buffer(const std::string& data)
{
return const_buffer_container_1(const_buffer(data.data(), data.size()));
}
/// Create a new non-modifiable buffer that represents the given string.
/**
* @note The buffer is invalidated by any non-const operation called on the
* given string object.
*/
inline const_buffer_container_1 buffer(const std::string& data,
std::size_t max_size_in_bytes)
{
return const_buffer_container_1(
const_buffer(data.data(),
data.size() < max_size_in_bytes
? data.size() : max_size_in_bytes));
}
/*@}*/
} // namespace asio
#include "asio/detail/pop_options.hpp"
#endif // ASIO_BUFFER_HPP