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Diffstat (limited to 'boost/endian/buffers.hpp')
-rw-r--r-- | boost/endian/buffers.hpp | 515 |
1 files changed, 515 insertions, 0 deletions
diff --git a/boost/endian/buffers.hpp b/boost/endian/buffers.hpp new file mode 100644 index 0000000000..b48b8de7d4 --- /dev/null +++ b/boost/endian/buffers.hpp @@ -0,0 +1,515 @@ +// 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/core/scoped_enum.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 +{ + + BOOST_SCOPED_ENUM_START(align) + {no, yes +# ifdef BOOST_ENDIAN_DEPRECATED_NAMES + , unaligned = no, aligned = yes +# endif + }; 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 signed integer buffers + typedef endian_buffer<order::big, int8_t, 8, align::yes> big_int8_buf_at; + typedef endian_buffer<order::big, int16_t, 16, align::yes> big_int16_buf_at; + typedef endian_buffer<order::big, int32_t, 32, align::yes> big_int32_buf_at; + typedef endian_buffer<order::big, int64_t, 64, align::yes> big_int64_buf_at; + + // aligned big endian unsigned integer buffers + typedef endian_buffer<order::big, uint8_t, 8, align::yes> big_uint8_buf_at; + typedef endian_buffer<order::big, uint16_t, 16, align::yes> big_uint16_buf_at; + typedef endian_buffer<order::big, uint32_t, 32, align::yes> big_uint32_buf_at; + typedef endian_buffer<order::big, uint64_t, 64, align::yes> big_uint64_buf_at; + + // aligned little endian signed integer buffers + typedef endian_buffer<order::little, int8_t, 8, align::yes> little_int8_buf_at; + typedef endian_buffer<order::little, int16_t, 16, align::yes> little_int16_buf_at; + typedef endian_buffer<order::little, int32_t, 32, align::yes> little_int32_buf_at; + typedef endian_buffer<order::little, int64_t, 64, align::yes> little_int64_buf_at; + + // aligned little endian unsigned integer buffers + typedef endian_buffer<order::little, uint8_t, 8, align::yes> little_uint8_buf_at; + typedef endian_buffer<order::little, uint16_t, 16, align::yes> little_uint16_buf_at; + typedef endian_buffer<order::little, uint32_t, 32, align::yes> little_uint32_buf_at; + typedef endian_buffer<order::little, uint64_t, 64, align::yes> little_uint64_buf_at; + + // aligned native endian typedefs are not provided because + // <cstdint> types are superior for this use case + + // unaligned big endian signed integer buffers + typedef endian_buffer<order::big, int_least8_t, 8> big_int8_buf_t; + typedef endian_buffer<order::big, int_least16_t, 16> big_int16_buf_t; + typedef endian_buffer<order::big, int_least32_t, 24> big_int24_buf_t; + typedef endian_buffer<order::big, int_least32_t, 32> big_int32_buf_t; + typedef endian_buffer<order::big, int_least64_t, 40> big_int40_buf_t; + typedef endian_buffer<order::big, int_least64_t, 48> big_int48_buf_t; + typedef endian_buffer<order::big, int_least64_t, 56> big_int56_buf_t; + typedef endian_buffer<order::big, int_least64_t, 64> big_int64_buf_t; + + // unaligned big endian unsigned integer buffers + typedef endian_buffer<order::big, uint_least8_t, 8> big_uint8_buf_t; + typedef endian_buffer<order::big, uint_least16_t, 16> big_uint16_buf_t; + typedef endian_buffer<order::big, uint_least32_t, 24> big_uint24_buf_t; + typedef endian_buffer<order::big, uint_least32_t, 32> big_uint32_buf_t; + typedef endian_buffer<order::big, uint_least64_t, 40> big_uint40_buf_t; + typedef endian_buffer<order::big, uint_least64_t, 48> big_uint48_buf_t; + typedef endian_buffer<order::big, uint_least64_t, 56> big_uint56_buf_t; + typedef endian_buffer<order::big, uint_least64_t, 64> big_uint64_buf_t; + + // unaligned little endian signed integer buffers + typedef endian_buffer<order::little, int_least8_t, 8> little_int8_buf_t; + typedef endian_buffer<order::little, int_least16_t, 16> little_int16_buf_t; + typedef endian_buffer<order::little, int_least32_t, 24> little_int24_buf_t; + typedef endian_buffer<order::little, int_least32_t, 32> little_int32_buf_t; + typedef endian_buffer<order::little, int_least64_t, 40> little_int40_buf_t; + typedef endian_buffer<order::little, int_least64_t, 48> little_int48_buf_t; + typedef endian_buffer<order::little, int_least64_t, 56> little_int56_buf_t; + typedef endian_buffer<order::little, int_least64_t, 64> little_int64_buf_t; + + // unaligned little endian unsigned integer buffers + typedef endian_buffer<order::little, uint_least8_t, 8> little_uint8_buf_t; + typedef endian_buffer<order::little, uint_least16_t, 16> little_uint16_buf_t; + typedef endian_buffer<order::little, uint_least32_t, 24> little_uint24_buf_t; + typedef endian_buffer<order::little, uint_least32_t, 32> little_uint32_buf_t; + typedef endian_buffer<order::little, uint_least64_t, 40> little_uint40_buf_t; + typedef endian_buffer<order::little, uint_least64_t, 48> little_uint48_buf_t; + typedef endian_buffer<order::little, uint_least64_t, 56> little_uint56_buf_t; + typedef endian_buffer<order::little, uint_least64_t, 64> little_uint64_buf_t; + +# ifdef BOOST_BIG_ENDIAN + // unaligned native endian signed integer buffers + typedef big_int8_buf_t native_int8_buf_t; + typedef big_int16_buf_t native_int16_buf_t; + typedef big_int24_buf_t native_int24_buf_t; + typedef big_int32_buf_t native_int32_buf_t; + typedef big_int40_buf_t native_int40_buf_t; + typedef big_int48_buf_t native_int48_buf_t; + typedef big_int56_buf_t native_int56_buf_t; + typedef big_int64_buf_t native_int64_buf_t; + + // unaligned native endian unsigned integer buffers + typedef big_uint8_buf_t native_uint8_buf_t; + typedef big_uint16_buf_t native_uint16_buf_t; + typedef big_uint24_buf_t native_uint24_buf_t; + typedef big_uint32_buf_t native_uint32_buf_t; + typedef big_uint40_buf_t native_uint40_buf_t; + typedef big_uint48_buf_t native_uint48_buf_t; + typedef big_uint56_buf_t native_uint56_buf_t; + typedef big_uint64_buf_t native_uint64_buf_t; +# else + // unaligned native endian signed integer buffers + typedef little_int8_buf_t native_int8_buf_t; + typedef little_int16_buf_t native_int16_buf_t; + typedef little_int24_buf_t native_int24_buf_t; + typedef little_int32_buf_t native_int32_buf_t; + typedef little_int40_buf_t native_int40_buf_t; + typedef little_int48_buf_t native_int48_buf_t; + typedef little_int56_buf_t native_int56_buf_t; + typedef little_int64_buf_t native_int64_buf_t; + + // unaligned native endian unsigned integer buffers + typedef little_uint8_buf_t native_uint8_buf_t; + typedef little_uint16_buf_t native_uint16_buf_t; + typedef little_uint24_buf_t native_uint24_buf_t; + typedef little_uint32_buf_t native_uint32_buf_t; + typedef little_uint40_buf_t native_uint40_buf_t; + typedef little_uint48_buf_t native_uint48_buf_t; + typedef little_uint56_buf_t native_uint56_buf_t; + typedef little_uint64_buf_t native_uint64_buf_t; +# endif + + // Stream inserter + template <class charT, class traits, BOOST_SCOPED_ENUM(order) Order, class T, + std::size_t n_bits, BOOST_SCOPED_ENUM(align) A> + std::basic_ostream<charT, traits>& + operator<<(std::basic_ostream<charT, traits>& os, + const endian_buffer<Order, T, n_bits, A>& x) + { + return os << x.value(); + } + + // Stream extractor + template <class charT, class traits, BOOST_SCOPED_ENUM(order) Order, class T, + std::size_t n_bits, BOOST_SCOPED_ENUM(align) A> + std::basic_istream<charT, traits>& + operator>>(std::basic_istream<charT, traits>& is, + endian_buffer<Order, T, n_bits, A>& x) + { + T i; + if (is >> i) + x = i; + return is; + } + +//---------------------------------- end synopsis ------------------------------------// + + 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 static_cast<T>(*(bytes - 1) | (next::load_big(bytes - 1) << 8)); } + static T load_little(const unsigned char* bytes) BOOST_NOEXCEPT + { return static_cast<T>(*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, static_cast<T>(value >> 8)); + } + static void store_little(char* bytes, T value) BOOST_NOEXCEPT + { + *bytes = static_cast<char>(value); + next::store_little(bytes + 1, static_cast<T>(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 + { +# if defined(__x86_64__) || defined(_M_X64) || defined(__i386) || defined(_M_IX86) + // On x86 (which is little endian), unaligned loads are permitted + if (sizeof(T) == n_bytes) // GCC 4.9, VC++ 14.0, and probably others, elide this + // test and generate code only for the applicable return + // case since sizeof(T) and n_bytes are known at compile + // time. + { + return *reinterpret_cast<T const *>(bytes); + } +# endif + 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 + { +# if defined(__x86_64__) || defined(_M_X64) || defined(__i386) || defined(_M_IX86) + // On x86 (which is little endian), unaligned stores are permitted + if (sizeof(T) == n_bytes) // GCC 4.9, VC++ 14.0, and probably others, elide this + // test and generate code only for the applicable return + // case since sizeof(T) and n_bytes are known at compile + // time. + { + *reinterpret_cast<T *>(bytes) = value; + return; + } +# endif + 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. + + // Q: Should endian_buffer supply "value_type operator value_type() const noexcept"? + // A: No. The rationale for endian_buffers is to prevent high-cost hidden + // conversions. If an implicit conversion operator is supplied, hidden conversions + // can occur. + + // 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 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::native_to_big(val); + } + +# endif + endian_buffer& operator=(T val) BOOST_NOEXCEPT + { + m_value = ::boost::endian::native_to_big(val); + return *this; + } + //operator value_type() const BOOST_NOEXCEPT + //{ + // return ::boost::endian::big_to_native(m_value); + //} + value_type value() const BOOST_NOEXCEPT + { +# ifdef BOOST_ENDIAN_LOG + if ( endian_log ) + std::cout << "big, aligned, " << n_bits << "-bits, convert(" + << ::boost::endian::big_to_native(m_value) << ")\n"; +# endif + return ::boost::endian::big_to_native(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::native_to_little(val); + } + +# endif + endian_buffer& operator=(T val) BOOST_NOEXCEPT + { + m_value = ::boost::endian::native_to_little(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_to_native(m_value) << ")\n"; +# endif + return ::boost::endian::little_to_native(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 |