1 // boost/endian/buffers.hpp ----------------------------------------------------------//
3 // (C) Copyright Darin Adler 2000
4 // (C) Copyright Beman Dawes 2006, 2009, 2014
6 // Distributed under the Boost Software License, Version 1.0.
7 // See http://www.boost.org/LICENSE_1_0.txt
9 // See library home page at http://www.boost.org/libs/endian
11 //--------------------------------------------------------------------------------------//
13 // Original design developed by Darin Adler based on classes developed by Mark
14 // Borgerding. Four original class templates were combined into a single endian
15 // class template by Beman Dawes, who also added the unrolled_byte_loops sign
16 // partial specialization to correctly extend the sign when cover integer size
17 // differs from endian representation size.
19 // TODO: When a compiler supporting constexpr becomes available, try possible uses.
21 #ifndef BOOST_ENDIAN_BUFFERS_HPP
22 #define BOOST_ENDIAN_BUFFERS_HPP
25 # pragma warning(push)
26 # pragma warning(disable:4365) // conversion ... signed/unsigned mismatch
29 #ifdef BOOST_ENDIAN_LOG
33 #if defined(__BORLANDC__) || defined( __CODEGEARC__)
34 # pragma pack(push, 1)
37 #include <boost/config.hpp>
38 #include <boost/predef/detail/endian_compat.h>
39 #include <boost/endian/conversion.hpp>
40 #include <boost/type_traits/is_signed.hpp>
41 #include <boost/cstdint.hpp>
42 #include <boost/static_assert.hpp>
43 #include <boost/core/scoped_enum.hpp>
48 # error Platforms with CHAR_BIT != 8 are not supported
51 # ifdef BOOST_NO_CXX11_DEFAULTED_FUNCTIONS
52 # define BOOST_ENDIAN_DEFAULT_CONSTRUCT {} // C++03
54 # define BOOST_ENDIAN_DEFAULT_CONSTRUCT = default; // C++0x
57 # if defined(BOOST_NO_CXX11_DEFAULTED_FUNCTIONS) && defined(BOOST_ENDIAN_FORCE_PODNESS)
58 # define BOOST_ENDIAN_NO_CTORS
61 //---------------------------------- synopsis ----------------------------------------//
68 BOOST_SCOPED_ENUM_START(align)
70 # ifdef BOOST_ENDIAN_DEPRECATED_NAMES
71 , unaligned = no, aligned = yes
73 }; BOOST_SCOPED_ENUM_END
75 template <BOOST_SCOPED_ENUM(order) Order, class T, std::size_t n_bits,
76 BOOST_SCOPED_ENUM(align) A = align::no>
79 // aligned big endian signed integer buffers
80 typedef endian_buffer<order::big, int8_t, 8, align::yes> big_int8_buf_at;
81 typedef endian_buffer<order::big, int16_t, 16, align::yes> big_int16_buf_at;
82 typedef endian_buffer<order::big, int32_t, 32, align::yes> big_int32_buf_at;
83 typedef endian_buffer<order::big, int64_t, 64, align::yes> big_int64_buf_at;
85 // aligned big endian unsigned integer buffers
86 typedef endian_buffer<order::big, uint8_t, 8, align::yes> big_uint8_buf_at;
87 typedef endian_buffer<order::big, uint16_t, 16, align::yes> big_uint16_buf_at;
88 typedef endian_buffer<order::big, uint32_t, 32, align::yes> big_uint32_buf_at;
89 typedef endian_buffer<order::big, uint64_t, 64, align::yes> big_uint64_buf_at;
91 // aligned little endian signed integer buffers
92 typedef endian_buffer<order::little, int8_t, 8, align::yes> little_int8_buf_at;
93 typedef endian_buffer<order::little, int16_t, 16, align::yes> little_int16_buf_at;
94 typedef endian_buffer<order::little, int32_t, 32, align::yes> little_int32_buf_at;
95 typedef endian_buffer<order::little, int64_t, 64, align::yes> little_int64_buf_at;
97 // aligned little endian unsigned integer buffers
98 typedef endian_buffer<order::little, uint8_t, 8, align::yes> little_uint8_buf_at;
99 typedef endian_buffer<order::little, uint16_t, 16, align::yes> little_uint16_buf_at;
100 typedef endian_buffer<order::little, uint32_t, 32, align::yes> little_uint32_buf_at;
101 typedef endian_buffer<order::little, uint64_t, 64, align::yes> little_uint64_buf_at;
103 // aligned native endian typedefs are not provided because
104 // <cstdint> types are superior for this use case
106 // unaligned big endian signed integer buffers
107 typedef endian_buffer<order::big, int_least8_t, 8> big_int8_buf_t;
108 typedef endian_buffer<order::big, int_least16_t, 16> big_int16_buf_t;
109 typedef endian_buffer<order::big, int_least32_t, 24> big_int24_buf_t;
110 typedef endian_buffer<order::big, int_least32_t, 32> big_int32_buf_t;
111 typedef endian_buffer<order::big, int_least64_t, 40> big_int40_buf_t;
112 typedef endian_buffer<order::big, int_least64_t, 48> big_int48_buf_t;
113 typedef endian_buffer<order::big, int_least64_t, 56> big_int56_buf_t;
114 typedef endian_buffer<order::big, int_least64_t, 64> big_int64_buf_t;
116 // unaligned big endian unsigned integer buffers
117 typedef endian_buffer<order::big, uint_least8_t, 8> big_uint8_buf_t;
118 typedef endian_buffer<order::big, uint_least16_t, 16> big_uint16_buf_t;
119 typedef endian_buffer<order::big, uint_least32_t, 24> big_uint24_buf_t;
120 typedef endian_buffer<order::big, uint_least32_t, 32> big_uint32_buf_t;
121 typedef endian_buffer<order::big, uint_least64_t, 40> big_uint40_buf_t;
122 typedef endian_buffer<order::big, uint_least64_t, 48> big_uint48_buf_t;
123 typedef endian_buffer<order::big, uint_least64_t, 56> big_uint56_buf_t;
124 typedef endian_buffer<order::big, uint_least64_t, 64> big_uint64_buf_t;
126 // unaligned little endian signed integer buffers
127 typedef endian_buffer<order::little, int_least8_t, 8> little_int8_buf_t;
128 typedef endian_buffer<order::little, int_least16_t, 16> little_int16_buf_t;
129 typedef endian_buffer<order::little, int_least32_t, 24> little_int24_buf_t;
130 typedef endian_buffer<order::little, int_least32_t, 32> little_int32_buf_t;
131 typedef endian_buffer<order::little, int_least64_t, 40> little_int40_buf_t;
132 typedef endian_buffer<order::little, int_least64_t, 48> little_int48_buf_t;
133 typedef endian_buffer<order::little, int_least64_t, 56> little_int56_buf_t;
134 typedef endian_buffer<order::little, int_least64_t, 64> little_int64_buf_t;
136 // unaligned little endian unsigned integer buffers
137 typedef endian_buffer<order::little, uint_least8_t, 8> little_uint8_buf_t;
138 typedef endian_buffer<order::little, uint_least16_t, 16> little_uint16_buf_t;
139 typedef endian_buffer<order::little, uint_least32_t, 24> little_uint24_buf_t;
140 typedef endian_buffer<order::little, uint_least32_t, 32> little_uint32_buf_t;
141 typedef endian_buffer<order::little, uint_least64_t, 40> little_uint40_buf_t;
142 typedef endian_buffer<order::little, uint_least64_t, 48> little_uint48_buf_t;
143 typedef endian_buffer<order::little, uint_least64_t, 56> little_uint56_buf_t;
144 typedef endian_buffer<order::little, uint_least64_t, 64> little_uint64_buf_t;
146 # ifdef BOOST_BIG_ENDIAN
147 // unaligned native endian signed integer buffers
148 typedef big_int8_buf_t native_int8_buf_t;
149 typedef big_int16_buf_t native_int16_buf_t;
150 typedef big_int24_buf_t native_int24_buf_t;
151 typedef big_int32_buf_t native_int32_buf_t;
152 typedef big_int40_buf_t native_int40_buf_t;
153 typedef big_int48_buf_t native_int48_buf_t;
154 typedef big_int56_buf_t native_int56_buf_t;
155 typedef big_int64_buf_t native_int64_buf_t;
157 // unaligned native endian unsigned integer buffers
158 typedef big_uint8_buf_t native_uint8_buf_t;
159 typedef big_uint16_buf_t native_uint16_buf_t;
160 typedef big_uint24_buf_t native_uint24_buf_t;
161 typedef big_uint32_buf_t native_uint32_buf_t;
162 typedef big_uint40_buf_t native_uint40_buf_t;
163 typedef big_uint48_buf_t native_uint48_buf_t;
164 typedef big_uint56_buf_t native_uint56_buf_t;
165 typedef big_uint64_buf_t native_uint64_buf_t;
167 // unaligned native endian signed integer buffers
168 typedef little_int8_buf_t native_int8_buf_t;
169 typedef little_int16_buf_t native_int16_buf_t;
170 typedef little_int24_buf_t native_int24_buf_t;
171 typedef little_int32_buf_t native_int32_buf_t;
172 typedef little_int40_buf_t native_int40_buf_t;
173 typedef little_int48_buf_t native_int48_buf_t;
174 typedef little_int56_buf_t native_int56_buf_t;
175 typedef little_int64_buf_t native_int64_buf_t;
177 // unaligned native endian unsigned integer buffers
178 typedef little_uint8_buf_t native_uint8_buf_t;
179 typedef little_uint16_buf_t native_uint16_buf_t;
180 typedef little_uint24_buf_t native_uint24_buf_t;
181 typedef little_uint32_buf_t native_uint32_buf_t;
182 typedef little_uint40_buf_t native_uint40_buf_t;
183 typedef little_uint48_buf_t native_uint48_buf_t;
184 typedef little_uint56_buf_t native_uint56_buf_t;
185 typedef little_uint64_buf_t native_uint64_buf_t;
189 template <class charT, class traits, BOOST_SCOPED_ENUM(order) Order, class T,
190 std::size_t n_bits, BOOST_SCOPED_ENUM(align) A>
191 std::basic_ostream<charT, traits>&
192 operator<<(std::basic_ostream<charT, traits>& os,
193 const endian_buffer<Order, T, n_bits, A>& x)
195 return os << x.value();
199 template <class charT, class traits, BOOST_SCOPED_ENUM(order) Order, class T,
200 std::size_t n_bits, BOOST_SCOPED_ENUM(align) A>
201 std::basic_istream<charT, traits>&
202 operator>>(std::basic_istream<charT, traits>& is,
203 endian_buffer<Order, T, n_bits, A>& x)
211 //---------------------------------- end synopsis ------------------------------------//
216 // Unrolled loops for loading and storing streams of bytes.
218 template <typename T, std::size_t n_bytes,
219 bool sign=boost::is_signed<T>::value >
220 struct unrolled_byte_loops
222 typedef unrolled_byte_loops<T, n_bytes - 1, sign> next;
224 static T load_big(const unsigned char* bytes) BOOST_NOEXCEPT
225 { return static_cast<T>(*(bytes - 1) | (next::load_big(bytes - 1) << 8)); }
226 static T load_little(const unsigned char* bytes) BOOST_NOEXCEPT
227 { return static_cast<T>(*bytes | (next::load_little(bytes + 1) << 8)); }
229 static void store_big(char* bytes, T value) BOOST_NOEXCEPT
231 *(bytes - 1) = static_cast<char>(value);
232 next::store_big(bytes - 1, static_cast<T>(value >> 8));
234 static void store_little(char* bytes, T value) BOOST_NOEXCEPT
236 *bytes = static_cast<char>(value);
237 next::store_little(bytes + 1, static_cast<T>(value >> 8));
241 template <typename T>
242 struct unrolled_byte_loops<T, 1, false>
244 static T load_big(const unsigned char* bytes) BOOST_NOEXCEPT
245 { return *(bytes - 1); }
246 static T load_little(const unsigned char* bytes) BOOST_NOEXCEPT
248 static void store_big(char* bytes, T value) BOOST_NOEXCEPT
249 { *(bytes - 1) = static_cast<char>(value); }
250 static void store_little(char* bytes, T value) BOOST_NOEXCEPT
251 { *bytes = static_cast<char>(value); }
255 template <typename T>
256 struct unrolled_byte_loops<T, 1, true>
258 static T load_big(const unsigned char* bytes) BOOST_NOEXCEPT
259 { return *reinterpret_cast<const signed char*>(bytes - 1); }
260 static T load_little(const unsigned char* bytes) BOOST_NOEXCEPT
261 { return *reinterpret_cast<const signed char*>(bytes); }
262 static void store_big(char* bytes, T value) BOOST_NOEXCEPT
263 { *(bytes - 1) = static_cast<char>(value); }
264 static void store_little(char* bytes, T value) BOOST_NOEXCEPT
265 { *bytes = static_cast<char>(value); }
268 template <typename T, std::size_t n_bytes>
270 T load_big_endian(const void* bytes) BOOST_NOEXCEPT
272 return unrolled_byte_loops<T, n_bytes>::load_big
273 (static_cast<const unsigned char*>(bytes) + n_bytes);
276 template <typename T, std::size_t n_bytes>
278 T load_little_endian(const void* bytes) BOOST_NOEXCEPT
280 # if defined(__x86_64__) || defined(_M_X64) || defined(__i386) || defined(_M_IX86)
281 // On x86 (which is little endian), unaligned loads are permitted
282 if (sizeof(T) == n_bytes) // GCC 4.9, VC++ 14.0, and probably others, elide this
283 // test and generate code only for the applicable return
284 // case since sizeof(T) and n_bytes are known at compile
287 return *reinterpret_cast<T const *>(bytes);
290 return unrolled_byte_loops<T, n_bytes>::load_little
291 (static_cast<const unsigned char*>(bytes));
294 template <typename T, std::size_t n_bytes>
296 void store_big_endian(void* bytes, T value) BOOST_NOEXCEPT
298 unrolled_byte_loops<T, n_bytes>::store_big
299 (static_cast<char*>(bytes) + n_bytes, value);
302 template <typename T, std::size_t n_bytes>
304 void store_little_endian(void* bytes, T value) BOOST_NOEXCEPT
306 # if defined(__x86_64__) || defined(_M_X64) || defined(__i386) || defined(_M_IX86)
307 // On x86 (which is little endian), unaligned stores are permitted
308 if (sizeof(T) == n_bytes) // GCC 4.9, VC++ 14.0, and probably others, elide this
309 // test and generate code only for the applicable return
310 // case since sizeof(T) and n_bytes are known at compile
313 *reinterpret_cast<T *>(bytes) = value;
317 unrolled_byte_loops<T, n_bytes>::store_little
318 (static_cast<char*>(bytes), value);
321 } // namespace detail
323 # ifdef BOOST_ENDIAN_LOG
324 bool endian_log(true);
327 // endian_buffer class template specializations --------------------------------------//
329 // Specializations that represent unaligned bytes.
330 // Taking an integer type as a parameter provides a nice way to pass both
331 // the size and signedness of the desired integer and get the appropriate
332 // corresponding integer type for the interface.
334 // Q: Should endian_buffer supply "value_type operator value_type() const noexcept"?
335 // A: No. The rationale for endian_buffers is to prevent high-cost hidden
336 // conversions. If an implicit conversion operator is supplied, hidden conversions
339 // unaligned big endian_buffer specialization
340 template <typename T, std::size_t n_bits>
341 class endian_buffer< order::big, T, n_bits, align::no >
343 BOOST_STATIC_ASSERT( (n_bits/8)*8 == n_bits );
345 typedef T value_type;
346 # ifndef BOOST_ENDIAN_NO_CTORS
347 endian_buffer() BOOST_ENDIAN_DEFAULT_CONSTRUCT
348 explicit endian_buffer(T val) BOOST_NOEXCEPT
350 # ifdef BOOST_ENDIAN_LOG
352 std::cout << "big, unaligned, "
353 << n_bits << "-bits, construct(" << val << ")\n";
355 detail::store_big_endian<T, n_bits/8>(m_value, val);
358 endian_buffer & operator=(T val) BOOST_NOEXCEPT
360 # ifdef BOOST_ENDIAN_LOG
362 std::cout << "big, unaligned, " << n_bits << "-bits, assign(" << val << ")\n";
364 detail::store_big_endian<T, n_bits/8>(m_value, val);
367 value_type value() const BOOST_NOEXCEPT
369 # ifdef BOOST_ENDIAN_LOG
371 std::cout << "big, unaligned, " << n_bits << "-bits, convert("
372 << detail::load_big_endian<T, n_bits/8>(m_value) << ")\n";
374 return detail::load_big_endian<T, n_bits/8>(m_value);
376 const char* data() const BOOST_NOEXCEPT { return m_value; }
378 char m_value[n_bits/8];
381 // unaligned little endian_buffer specialization
382 template <typename T, std::size_t n_bits>
383 class endian_buffer< order::little, T, n_bits, align::no >
385 BOOST_STATIC_ASSERT( (n_bits/8)*8 == n_bits );
387 typedef T value_type;
388 # ifndef BOOST_ENDIAN_NO_CTORS
389 endian_buffer() BOOST_ENDIAN_DEFAULT_CONSTRUCT
390 explicit endian_buffer(T val) BOOST_NOEXCEPT
392 # ifdef BOOST_ENDIAN_LOG
394 std::cout << "little, unaligned, " << n_bits << "-bits, construct("
397 detail::store_little_endian<T, n_bits/8>(m_value, val);
400 endian_buffer & operator=(T val) BOOST_NOEXCEPT
401 { detail::store_little_endian<T, n_bits/8>(m_value, val); return *this; }
402 value_type value() const BOOST_NOEXCEPT
404 # ifdef BOOST_ENDIAN_LOG
406 std::cout << "little, unaligned, " << n_bits << "-bits, convert("
407 << detail::load_little_endian<T, n_bits/8>(m_value) << ")\n";
409 return detail::load_little_endian<T, n_bits/8>(m_value);
411 const char* data() const BOOST_NOEXCEPT { return m_value; }
413 char m_value[n_bits/8];
416 // align::yes specializations; only n_bits == 16/32/64 supported
418 // aligned big endian_buffer specialization
419 template <typename T, std::size_t n_bits>
420 class endian_buffer<order::big, T, n_bits, align::yes>
422 BOOST_STATIC_ASSERT( (n_bits/8)*8 == n_bits );
423 BOOST_STATIC_ASSERT( sizeof(T) == n_bits/8 );
425 typedef T value_type;
426 # ifndef BOOST_ENDIAN_NO_CTORS
427 endian_buffer() BOOST_ENDIAN_DEFAULT_CONSTRUCT
428 explicit endian_buffer(T val) BOOST_NOEXCEPT
430 # ifdef BOOST_ENDIAN_LOG
432 std::cout << "big, aligned, " << n_bits
433 << "-bits, construct(" << val << ")\n";
435 m_value = ::boost::endian::native_to_big(val);
439 endian_buffer& operator=(T val) BOOST_NOEXCEPT
441 m_value = ::boost::endian::native_to_big(val);
444 //operator value_type() const BOOST_NOEXCEPT
446 // return ::boost::endian::big_to_native(m_value);
448 value_type value() const BOOST_NOEXCEPT
450 # ifdef BOOST_ENDIAN_LOG
452 std::cout << "big, aligned, " << n_bits << "-bits, convert("
453 << ::boost::endian::big_to_native(m_value) << ")\n";
455 return ::boost::endian::big_to_native(m_value);
457 const char* data() const BOOST_NOEXCEPT
458 {return reinterpret_cast<const char*>(&m_value);}
463 // aligned little endian_buffer specialization
464 template <typename T, std::size_t n_bits>
465 class endian_buffer<order::little, T, n_bits, align::yes>
467 BOOST_STATIC_ASSERT( (n_bits/8)*8 == n_bits );
468 BOOST_STATIC_ASSERT( sizeof(T) == n_bits/8 );
470 typedef T value_type;
471 # ifndef BOOST_ENDIAN_NO_CTORS
472 endian_buffer() BOOST_ENDIAN_DEFAULT_CONSTRUCT
473 explicit endian_buffer(T val) BOOST_NOEXCEPT
475 # ifdef BOOST_ENDIAN_LOG
477 std::cout << "little, aligned, " << n_bits
478 << "-bits, construct(" << val << ")\n";
480 m_value = ::boost::endian::native_to_little(val);
484 endian_buffer& operator=(T val) BOOST_NOEXCEPT
486 m_value = ::boost::endian::native_to_little(val);
489 value_type value() const BOOST_NOEXCEPT
491 # ifdef BOOST_ENDIAN_LOG
493 std::cout << "little, aligned, " << n_bits << "-bits, convert("
494 << ::boost::endian::little_to_native(m_value) << ")\n";
496 return ::boost::endian::little_to_native(m_value);
498 const char* data() const BOOST_NOEXCEPT
499 {return reinterpret_cast<const char*>(&m_value);}
504 } // namespace endian
507 #if defined(__BORLANDC__) || defined( __CODEGEARC__)
511 #if defined(_MSC_VER)
512 # pragma warning(pop)
515 #endif // BOOST_ENDIAN_BUFFERS_HPP