Files
boost_endian/include/boost/endian/buffers.hpp
T

596 lines
22 KiB
C++

// boost/endian/buffers.hpp ----------------------------------------------------------//
// (C) Copyright Darin Adler 2000
// (C) Copyright Beman Dawes 2006, 2009, 2014
// Distributed under the Boost Software License, Version 1.0.
// See http://www.boost.org/LICENSE_1_0.txt
// See library home page at http://www.boost.org/libs/endian
//--------------------------------------------------------------------------------------//
// Original design developed by Darin Adler based on classes developed by Mark
// Borgerding. Four original class templates were combined into a single endian
// class template by Beman Dawes, who also added the unrolled_byte_loops sign
// partial specialization to correctly extend the sign when cover integer size
// differs from endian representation size.
// TODO: When a compiler supporting constexpr becomes available, try possible uses.
#ifndef BOOST_ENDIAN_BUFFERS_HPP
#define BOOST_ENDIAN_BUFFERS_HPP
#if defined(_MSC_VER)
# pragma warning(push)
# pragma warning(disable:4365) // conversion ... signed/unsigned mismatch
#endif
#ifdef BOOST_ENDIAN_LOG
# include <iostream>
#endif
#if defined(__BORLANDC__) || defined( __CODEGEARC__)
# pragma pack(push, 1)
#endif
#include <boost/config.hpp>
#include <boost/predef/detail/endian_compat.h>
#include <boost/endian/conversion.hpp>
#include <boost/type_traits/is_signed.hpp>
#include <boost/cstdint.hpp>
#include <boost/static_assert.hpp>
#include <boost/detail/scoped_enum_emulation.hpp>
#include <iosfwd>
#include <climits>
# if CHAR_BIT != 8
# error Platforms with CHAR_BIT != 8 are not supported
# endif
# ifdef BOOST_NO_CXX11_DEFAULTED_FUNCTIONS
# define BOOST_ENDIAN_DEFAULT_CONSTRUCT {} // C++03
# else
# define BOOST_ENDIAN_DEFAULT_CONSTRUCT = default; // C++0x
# endif
# if defined(BOOST_NO_CXX11_DEFAULTED_FUNCTIONS) && defined(BOOST_ENDIAN_FORCE_PODNESS)
# define BOOST_ENDIAN_NO_CTORS
# endif
//---------------------------------- synopsis ----------------------------------------//
namespace boost
{
namespace endian
{
#ifndef BOOST_ENDIAN_ORDER_ENUM_DEFINED
BOOST_SCOPED_ENUM_START(order)
{
big, little,
# ifdef BOOST_BIG_ENDIAN
native = big
# else
native = little
# endif
}; BOOST_SCOPED_ENUM_END
# define BOOST_ENDIAN_ORDER_ENUM_DEFINED
#endif
BOOST_SCOPED_ENUM_START(align) {no, yes}; BOOST_SCOPED_ENUM_END
template <BOOST_SCOPED_ENUM(order) Order, class T, std::size_t n_bits,
BOOST_SCOPED_ENUM(align) A = align::no>
class endian_buffer;
// aligned big endian floating point types
typedef endian_buffer<order::big, float, 32, align::yes> big_floatbuf32_t;
typedef endian_buffer<order::big, double, 64, align::yes> big_floatbuf64_t;
// aligned little endian floating point types
typedef endian_buffer<order::little, float, 32, align::yes> little_floatbuf32_t;
typedef endian_buffer<order::little, double, 64, align::yes> little_floatbuf64_t;
// unaligned big endian floating point types
typedef endian_buffer<order::big, float, 32, align::no> big_floatbuf32_ut;
typedef endian_buffer<order::big, double, 64, align::no> big_floatbuf64_ut;
// unaligned little endian floating point types
typedef endian_buffer<order::little, float, 32, align::no> little_floatbuf32_ut;
typedef endian_buffer<order::little, double, 64, align::no> little_floatbuf64_ut;
// aligned big endian signed integer types
typedef endian_buffer<order::big, int16_t, 16, align::yes> big_buf16_t;
typedef endian_buffer<order::big, int32_t, 32, align::yes> big_buf32_t;
typedef endian_buffer<order::big, int64_t, 64, align::yes> big_buf64_t;
// aligned big endian unsigned integer types
typedef endian_buffer<order::big, uint16_t, 16, align::yes> big_ubuf16_t;
typedef endian_buffer<order::big, uint32_t, 32, align::yes> big_ubuf32_t;
typedef endian_buffer<order::big, uint64_t, 64, align::yes> big_ubuf64_t;
// aligned little endian signed integer types
typedef endian_buffer<order::little, int16_t, 16, align::yes> little_buf16_t;
typedef endian_buffer<order::little, int32_t, 32, align::yes> little_buf32_t;
typedef endian_buffer<order::little, int64_t, 64, align::yes> little_buf64_t;
// aligned little endian unsigned integer types
typedef endian_buffer<order::little, uint16_t, 16, align::yes> little_ubuf16_t;
typedef endian_buffer<order::little, uint32_t, 32, align::yes> little_ubuf32_t;
typedef endian_buffer<order::little, uint64_t, 64, align::yes> little_ubuf64_t;
// aligned native endian typedefs are not provided because
// <cstdint> types are superior for this use case
// unaligned big endian signed integer types
typedef endian_buffer<order::big, int_least8_t, 8> big_buf8_ut;
typedef endian_buffer<order::big, int_least16_t, 16> big_buf16_ut;
typedef endian_buffer<order::big, int_least32_t, 24> big_buf24_ut;
typedef endian_buffer<order::big, int_least32_t, 32> big_buf32_ut;
typedef endian_buffer<order::big, int_least64_t, 40> big_buf40_ut;
typedef endian_buffer<order::big, int_least64_t, 48> big_buf48_ut;
typedef endian_buffer<order::big, int_least64_t, 56> big_buf56_ut;
typedef endian_buffer<order::big, int_least64_t, 64> big_buf64_ut;
// unaligned big endian unsigned integer types
typedef endian_buffer<order::big, uint_least8_t, 8> big_ubuf8_ut;
typedef endian_buffer<order::big, uint_least16_t, 16> big_ubuf16_ut;
typedef endian_buffer<order::big, uint_least32_t, 24> big_ubuf24_ut;
typedef endian_buffer<order::big, uint_least32_t, 32> big_ubuf32_ut;
typedef endian_buffer<order::big, uint_least64_t, 40> big_ubuf40_ut;
typedef endian_buffer<order::big, uint_least64_t, 48> big_ubuf48_ut;
typedef endian_buffer<order::big, uint_least64_t, 56> big_ubuf56_ut;
typedef endian_buffer<order::big, uint_least64_t, 64> big_ubuf64_ut;
// unaligned little endian signed integer types
typedef endian_buffer<order::little, int_least8_t, 8> little_buf8_ut;
typedef endian_buffer<order::little, int_least16_t, 16> little_buf16_ut;
typedef endian_buffer<order::little, int_least32_t, 24> little_buf24_ut;
typedef endian_buffer<order::little, int_least32_t, 32> little_buf32_ut;
typedef endian_buffer<order::little, int_least64_t, 40> little_buf40_ut;
typedef endian_buffer<order::little, int_least64_t, 48> little_buf48_ut;
typedef endian_buffer<order::little, int_least64_t, 56> little_buf56_ut;
typedef endian_buffer<order::little, int_least64_t, 64> little_buf64_ut;
// unaligned little endian unsigned integer types
typedef endian_buffer<order::little, uint_least8_t, 8> little_ubuf8_ut;
typedef endian_buffer<order::little, uint_least16_t, 16> little_ubuf16_ut;
typedef endian_buffer<order::little, uint_least32_t, 24> little_ubuf24_ut;
typedef endian_buffer<order::little, uint_least32_t, 32> little_ubuf32_ut;
typedef endian_buffer<order::little, uint_least64_t, 40> little_ubuf40_ut;
typedef endian_buffer<order::little, uint_least64_t, 48> little_ubuf48_ut;
typedef endian_buffer<order::little, uint_least64_t, 56> little_ubuf56_ut;
typedef endian_buffer<order::little, uint_least64_t, 64> little_ubuf64_ut;
# ifdef BOOST_BIG_ENDIAN
// unaligned native endian signed integer types
typedef big_buf8_ut native_buf8_ut;
typedef big_buf16_ut native_buf16_ut;
typedef big_buf24_ut native_buf24_ut;
typedef big_buf32_ut native_buf32_ut;
typedef big_buf40_ut native_buf40_ut;
typedef big_buf48_ut native_buf48_ut;
typedef big_buf56_ut native_buf56_ut;
typedef big_buf64_ut native_buf64_ut;
// unaligned native endian unsigned integer types
typedef big_ubuf8_ut native_ubuf8_ut;
typedef big_ubuf16_ut native_ubuf16_ut;
typedef big_ubuf24_ut native_ubuf24_ut;
typedef big_ubuf32_ut native_ubuf32_ut;
typedef big_ubuf40_ut native_ubuf40_ut;
typedef big_ubuf48_ut native_ubuf48_ut;
typedef big_ubuf56_ut native_ubuf56_ut;
typedef big_ubuf64_ut native_ubuf64_ut;
// native endian floating point types
typedef big_floatbuf32_ut native_floatbuf32_ut;
typedef big_floatbuf64_ut native_floatbuf64_ut;
typedef big_floatbuf32_t native_floatbuf32_t;
typedef big_floatbuf64_t native_floatbuf64_t;
# else
// unaligned native endian signed integer types
typedef little_buf8_ut native_buf8_ut;
typedef little_buf16_ut native_buf16_ut;
typedef little_buf24_ut native_buf24_ut;
typedef little_buf32_ut native_buf32_ut;
typedef little_buf40_ut native_buf40_ut;
typedef little_buf48_ut native_buf48_ut;
typedef little_buf56_ut native_buf56_ut;
typedef little_buf64_ut native_buf64_ut;
// unaligned native endian unsigned integer types
typedef little_ubuf8_ut native_ubuf8_ut;
typedef little_ubuf16_ut native_ubuf16_ut;
typedef little_ubuf24_ut native_ubuf24_ut;
typedef little_ubuf32_ut native_ubuf32_ut;
typedef little_ubuf40_ut native_ubuf40_ut;
typedef little_ubuf48_ut native_ubuf48_ut;
typedef little_ubuf56_ut native_ubuf56_ut;
typedef little_ubuf64_ut native_ubuf64_ut;
// native endian floating point types
typedef little_floatbuf32_ut native_floatbuf32_ut;
typedef little_floatbuf64_ut native_floatbuf64_ut;
typedef little_floatbuf32_t native_floatbuf32_t;
typedef little_floatbuf64_t native_floatbuf64_t;
# endif
} // namespace boost
} // namespace endian
//---------------------------------- end synopsis ------------------------------------//
namespace boost
{
namespace endian
{
namespace detail
{
// Unrolled loops for loading and storing streams of bytes.
template <typename T, std::size_t n_bytes,
bool sign=boost::is_signed<T>::value >
struct unrolled_byte_loops
{
typedef unrolled_byte_loops<T, n_bytes - 1, sign> next;
static T load_big(const unsigned char* bytes) BOOST_NOEXCEPT
{ return *(bytes - 1) | (next::load_big(bytes - 1) << 8); }
static T load_little(const unsigned char* bytes) BOOST_NOEXCEPT
{ return *bytes | (next::load_little(bytes + 1) << 8); }
static void store_big(char* bytes, T value) BOOST_NOEXCEPT
{
*(bytes - 1) = static_cast<char>(value);
next::store_big(bytes - 1, value >> 8);
}
static void store_little(char* bytes, T value) BOOST_NOEXCEPT
{
*bytes = static_cast<char>(value);
next::store_little(bytes + 1, value >> 8);
}
};
template <typename T>
struct unrolled_byte_loops<T, 1, false>
{
static T load_big(const unsigned char* bytes) BOOST_NOEXCEPT
{ return *(bytes - 1); }
static T load_little(const unsigned char* bytes) BOOST_NOEXCEPT
{ return *bytes; }
static void store_big(char* bytes, T value) BOOST_NOEXCEPT
{ *(bytes - 1) = static_cast<char>(value); }
static void store_little(char* bytes, T value) BOOST_NOEXCEPT
{ *bytes = static_cast<char>(value); }
};
template <typename T>
struct unrolled_byte_loops<T, 1, true>
{
static T load_big(const unsigned char* bytes) BOOST_NOEXCEPT
{ return *reinterpret_cast<const signed char*>(bytes - 1); }
static T load_little(const unsigned char* bytes) BOOST_NOEXCEPT
{ return *reinterpret_cast<const signed char*>(bytes); }
static void store_big(char* bytes, T value) BOOST_NOEXCEPT
{ *(bytes - 1) = static_cast<char>(value); }
static void store_little(char* bytes, T value) BOOST_NOEXCEPT
{ *bytes = static_cast<char>(value); }
};
template <typename T, std::size_t n_bytes>
inline
T load_big_endian(const void* bytes) BOOST_NOEXCEPT
{
return unrolled_byte_loops<T, n_bytes>::load_big
(static_cast<const unsigned char*>(bytes) + n_bytes);
}
template <typename T, std::size_t n_bytes>
inline
T load_little_endian(const void* bytes) BOOST_NOEXCEPT
{
return unrolled_byte_loops<T, n_bytes>::load_little
(static_cast<const unsigned char*>(bytes));
}
template <typename T, std::size_t n_bytes>
inline
void store_big_endian(void* bytes, T value) BOOST_NOEXCEPT
{
unrolled_byte_loops<T, n_bytes>::store_big
(static_cast<char*>(bytes) + n_bytes, value);
}
template <typename T, std::size_t n_bytes>
inline
void store_little_endian(void* bytes, T value) BOOST_NOEXCEPT
{
unrolled_byte_loops<T, n_bytes>::store_little
(static_cast<char*>(bytes), value);
}
} // namespace detail
# ifdef BOOST_ENDIAN_LOG
bool endian_log(true);
# endif
// endian_buffer class template specializations --------------------------------------//
// Specializations that represent unaligned bytes.
// Taking an integer type as a parameter provides a nice way to pass both
// the size and signedness of the desired integer and get the appropriate
// corresponding integer type for the interface.
// unaligned big endian_buffer specialization
template <typename T, std::size_t n_bits>
class endian_buffer< order::big, T, n_bits, align::no >
{
BOOST_STATIC_ASSERT( (n_bits/8)*8 == n_bits );
public:
typedef T value_type;
# ifndef BOOST_ENDIAN_NO_CTORS
endian_buffer() BOOST_ENDIAN_DEFAULT_CONSTRUCT
explicit endian_buffer(T val) BOOST_NOEXCEPT
{
# ifdef BOOST_ENDIAN_LOG
if ( endian_log )
std::cout << "big, unaligned, "
<< n_bits << "-bits, construct(" << val << ")\n";
# endif
detail::store_big_endian<T, n_bits/8>(m_value, val);
}
# endif
endian_buffer & operator=(T val) BOOST_NOEXCEPT
{
# ifdef BOOST_ENDIAN_LOG
if (endian_log)
std::cout << "big, unaligned, " << n_bits << "-bits, assign(" << val << ")\n";
# endif
detail::store_big_endian<T, n_bits/8>(m_value, val);
return *this;
}
value_type value() const BOOST_NOEXCEPT
{
# ifdef BOOST_ENDIAN_LOG
if ( endian_log )
std::cout << "big, unaligned, " << n_bits << "-bits, convert("
<< detail::load_big_endian<T, n_bits/8>(m_value) << ")\n";
# endif
return detail::load_big_endian<T, n_bits/8>(m_value);
}
const char* data() const BOOST_NOEXCEPT { return m_value; }
protected:
char m_value[n_bits/8];
};
// unaligned float big endian_buffer specialization
template <>
class endian_buffer< order::big, float, 32, align::no >
{
public:
typedef float value_type;
# ifndef BOOST_ENDIAN_NO_CTORS
endian_buffer() BOOST_ENDIAN_DEFAULT_CONSTRUCT
explicit endian_buffer(value_type val) BOOST_NOEXCEPT
{ detail::big_reverse_copy(val, m_value); }
# endif
endian_buffer & operator=(value_type val) BOOST_NOEXCEPT
{ detail::big_reverse_copy(val, m_value); return *this; }
value_type value() const BOOST_NOEXCEPT
{
value_type tmp;
detail::big_reverse_copy(m_value, tmp);
return tmp;
}
const char* data() const BOOST_NOEXCEPT { return m_value; }
protected:
char m_value[sizeof(value_type)];
};
// unaligned double big endian_buffer specialization
template <>
class endian_buffer< order::big, double, 64, align::no >
{
public:
typedef double value_type;
# ifndef BOOST_ENDIAN_NO_CTORS
endian_buffer() BOOST_ENDIAN_DEFAULT_CONSTRUCT
explicit endian_buffer(value_type val) BOOST_NOEXCEPT
{ detail::big_reverse_copy(val, m_value); }
# endif
endian_buffer & operator=(value_type val) BOOST_NOEXCEPT
{ detail::big_reverse_copy(val, m_value); return *this; }
value_type value() const BOOST_NOEXCEPT
{
value_type tmp;
detail::big_reverse_copy(m_value, tmp);
return tmp;
}
const char* data() const BOOST_NOEXCEPT { return m_value; }
protected:
char m_value[sizeof(value_type)];
};
// unaligned float little endian_buffer specialization
template <>
class endian_buffer< order::little, float, 32, align::no >
{
public:
typedef float value_type;
# ifndef BOOST_ENDIAN_NO_CTORS
endian_buffer() BOOST_ENDIAN_DEFAULT_CONSTRUCT
explicit endian_buffer(value_type val) BOOST_NOEXCEPT
{ detail::little_reverse_copy(val, m_value); }
# endif
endian_buffer & operator=(value_type val) BOOST_NOEXCEPT
{ detail::little_reverse_copy(val, m_value); return *this; }
value_type value() const BOOST_NOEXCEPT
{
value_type tmp;
detail::little_reverse_copy(m_value, tmp);
return tmp;
}
const char* data() const BOOST_NOEXCEPT { return m_value; }
protected:
char m_value[sizeof(value_type)];
};
// unaligned double little endian_buffer specialization
template <>
class endian_buffer< order::little, double, 64, align::no >
{
public:
typedef double value_type;
# ifndef BOOST_ENDIAN_NO_CTORS
endian_buffer() BOOST_ENDIAN_DEFAULT_CONSTRUCT
explicit endian_buffer(value_type val) BOOST_NOEXCEPT
{ detail::little_reverse_copy(val, m_value); }
# endif
endian_buffer & operator=(value_type val) BOOST_NOEXCEPT
{ detail::little_reverse_copy(val, m_value); return *this; }
value_type value() const BOOST_NOEXCEPT
{
value_type tmp;
detail::little_reverse_copy(m_value, tmp);
return tmp;
}
const char* data() const BOOST_NOEXCEPT { return m_value; }
protected:
char m_value[sizeof(value_type)];
};
// unaligned little endian_buffer specialization
template <typename T, std::size_t n_bits>
class endian_buffer< order::little, T, n_bits, align::no >
{
BOOST_STATIC_ASSERT( (n_bits/8)*8 == n_bits );
public:
typedef T value_type;
# ifndef BOOST_ENDIAN_NO_CTORS
endian_buffer() BOOST_ENDIAN_DEFAULT_CONSTRUCT
explicit endian_buffer(T val) BOOST_NOEXCEPT
{
# ifdef BOOST_ENDIAN_LOG
if ( endian_log )
std::cout << "little, unaligned, " << n_bits << "-bits, construct("
<< val << ")\n";
# endif
detail::store_little_endian<T, n_bits/8>(m_value, val);
}
# endif
endian_buffer & operator=(T val) BOOST_NOEXCEPT
{ detail::store_little_endian<T, n_bits/8>(m_value, val); return *this; }
value_type value() const BOOST_NOEXCEPT
{
# ifdef BOOST_ENDIAN_LOG
if ( endian_log )
std::cout << "little, unaligned, " << n_bits << "-bits, convert("
<< detail::load_little_endian<T, n_bits/8>(m_value) << ")\n";
# endif
return detail::load_little_endian<T, n_bits/8>(m_value);
}
const char* data() const BOOST_NOEXCEPT { return m_value; }
protected:
char m_value[n_bits/8];
};
// align::yes specializations; only n_bits == 16/32/64 supported
// aligned big endian_buffer specialization
template <typename T, std::size_t n_bits>
class endian_buffer<order::big, T, n_bits, align::yes>
{
BOOST_STATIC_ASSERT( (n_bits/8)*8 == n_bits );
BOOST_STATIC_ASSERT( sizeof(T) == n_bits/8 );
public:
typedef T value_type;
# ifndef BOOST_ENDIAN_NO_CTORS
endian_buffer() BOOST_ENDIAN_DEFAULT_CONSTRUCT
explicit endian_buffer(T val) BOOST_NOEXCEPT
{
# ifdef BOOST_ENDIAN_LOG
if ( endian_log )
std::cout << "big, aligned, " << n_bits
<< "-bits, construct(" << val << ")\n";
# endif
m_value = ::boost::endian::big_endian_value(val);
}
# endif
endian_buffer& operator=(T val) BOOST_NOEXCEPT
{
m_value = ::boost::endian::big_endian_value(val);
return *this;
}
value_type value() const BOOST_NOEXCEPT
{
# ifdef BOOST_ENDIAN_LOG
if ( endian_log )
std::cout << "big, aligned, " << n_bits << "-bits, convert("
<< ::boost::endian::big_endian_value(m_value) << ")\n";
# endif
return ::boost::endian::big_endian_value(m_value);
}
const char* data() const BOOST_NOEXCEPT
{return reinterpret_cast<const char*>(&m_value);}
protected:
T m_value;
};
// aligned little endian_buffer specialization
template <typename T, std::size_t n_bits>
class endian_buffer<order::little, T, n_bits, align::yes>
{
BOOST_STATIC_ASSERT( (n_bits/8)*8 == n_bits );
BOOST_STATIC_ASSERT( sizeof(T) == n_bits/8 );
public:
typedef T value_type;
# ifndef BOOST_ENDIAN_NO_CTORS
endian_buffer() BOOST_ENDIAN_DEFAULT_CONSTRUCT
explicit endian_buffer(T val) BOOST_NOEXCEPT
{
# ifdef BOOST_ENDIAN_LOG
if ( endian_log )
std::cout << "little, aligned, " << n_bits
<< "-bits, construct(" << val << ")\n";
# endif
m_value = ::boost::endian::little_endian_value(val);
}
# endif
endian_buffer& operator=(T val) BOOST_NOEXCEPT
{
m_value = ::boost::endian::little_endian_value(val);
return *this;
}
value_type value() const BOOST_NOEXCEPT
{
# ifdef BOOST_ENDIAN_LOG
if ( endian_log )
std::cout << "little, aligned, " << n_bits << "-bits, convert("
<< ::boost::endian::little_endian_value(m_value) << ")\n";
# endif
return ::boost::endian::little_endian_value(m_value);
}
const char* data() const BOOST_NOEXCEPT
{return reinterpret_cast<const char*>(&m_value);}
protected:
T m_value;
};
} // namespace endian
} // namespace boost
#if defined(__BORLANDC__) || defined( __CODEGEARC__)
# pragma pack(pop)
#endif
#if defined(_MSC_VER)
# pragma warning(pop)
#endif
#endif // BOOST_ENDIAN_BUFFERS_HPP