buffers.hpp 14 KB

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  1. // boost/endian/buffers.hpp ----------------------------------------------------------//
  2. // (C) Copyright Darin Adler 2000
  3. // (C) Copyright Beman Dawes 2006, 2009, 2014
  4. // (C) Copyright Peter Dimov 2019
  5. // Distributed under the Boost Software License, Version 1.0.
  6. // See http://www.boost.org/LICENSE_1_0.txt
  7. // See library home page at http://www.boost.org/libs/endian
  8. //--------------------------------------------------------------------------------------//
  9. // Original design developed by Darin Adler based on classes developed by Mark
  10. // Borgerding. Four original class templates were combined into a single endian
  11. // class template by Beman Dawes, who also added the unrolled_byte_loops sign
  12. // partial specialization to correctly extend the sign when cover integer size
  13. // differs from endian representation size.
  14. // TODO: When a compiler supporting constexpr becomes available, try possible uses.
  15. #ifndef BOOST_ENDIAN_BUFFERS_HPP
  16. #define BOOST_ENDIAN_BUFFERS_HPP
  17. #if defined(_MSC_VER)
  18. # pragma warning(push)
  19. # pragma warning(disable: 4127) // conditional expression is constant
  20. #endif
  21. #include <boost/endian/detail/requires_cxx11.hpp>
  22. #include <boost/endian/detail/endian_store.hpp>
  23. #include <boost/endian/detail/endian_load.hpp>
  24. #include <boost/core/scoped_enum.hpp>
  25. #include <boost/static_assert.hpp>
  26. #include <boost/cstdint.hpp>
  27. #include <boost/config.hpp>
  28. #include <boost/config/workaround.hpp>
  29. #include <iosfwd>
  30. #include <climits>
  31. #include <cstring>
  32. #if defined(BOOST_BORLANDC) || defined(BOOST_CODEGEARC)
  33. # pragma pack(push, 1)
  34. #endif
  35. # if CHAR_BIT != 8
  36. # error Platforms with CHAR_BIT != 8 are not supported
  37. # endif
  38. # ifdef BOOST_NO_CXX11_DEFAULTED_FUNCTIONS
  39. # define BOOST_ENDIAN_DEFAULT_CONSTRUCT {} // C++03
  40. # else
  41. # define BOOST_ENDIAN_DEFAULT_CONSTRUCT = default; // C++0x
  42. # endif
  43. // g++ pre-4.6 does not support unrestricted unions, but we have no Config macro for that
  44. # if (defined(BOOST_NO_CXX11_DEFAULTED_FUNCTIONS) || BOOST_WORKAROUND(BOOST_GCC, < 40600)) && defined(BOOST_ENDIAN_FORCE_PODNESS)
  45. # define BOOST_ENDIAN_NO_CTORS
  46. # endif
  47. //---------------------------------- synopsis ----------------------------------------//
  48. namespace boost
  49. {
  50. namespace endian
  51. {
  52. BOOST_SCOPED_ENUM_START(align)
  53. {no, yes
  54. # ifdef BOOST_ENDIAN_DEPRECATED_NAMES
  55. , unaligned = no, aligned = yes
  56. # endif
  57. }; BOOST_SCOPED_ENUM_END
  58. template <BOOST_SCOPED_ENUM(order) Order, class T, std::size_t n_bits,
  59. BOOST_SCOPED_ENUM(align) A = align::no>
  60. class endian_buffer;
  61. // aligned big endian signed integer buffers
  62. typedef endian_buffer<order::big, int8_t, 8, align::yes> big_int8_buf_at;
  63. typedef endian_buffer<order::big, int16_t, 16, align::yes> big_int16_buf_at;
  64. typedef endian_buffer<order::big, int32_t, 32, align::yes> big_int32_buf_at;
  65. typedef endian_buffer<order::big, int64_t, 64, align::yes> big_int64_buf_at;
  66. // aligned big endian unsigned integer buffers
  67. typedef endian_buffer<order::big, uint8_t, 8, align::yes> big_uint8_buf_at;
  68. typedef endian_buffer<order::big, uint16_t, 16, align::yes> big_uint16_buf_at;
  69. typedef endian_buffer<order::big, uint32_t, 32, align::yes> big_uint32_buf_at;
  70. typedef endian_buffer<order::big, uint64_t, 64, align::yes> big_uint64_buf_at;
  71. // aligned little endian signed integer buffers
  72. typedef endian_buffer<order::little, int8_t, 8, align::yes> little_int8_buf_at;
  73. typedef endian_buffer<order::little, int16_t, 16, align::yes> little_int16_buf_at;
  74. typedef endian_buffer<order::little, int32_t, 32, align::yes> little_int32_buf_at;
  75. typedef endian_buffer<order::little, int64_t, 64, align::yes> little_int64_buf_at;
  76. // aligned little endian unsigned integer buffers
  77. typedef endian_buffer<order::little, uint8_t, 8, align::yes> little_uint8_buf_at;
  78. typedef endian_buffer<order::little, uint16_t, 16, align::yes> little_uint16_buf_at;
  79. typedef endian_buffer<order::little, uint32_t, 32, align::yes> little_uint32_buf_at;
  80. typedef endian_buffer<order::little, uint64_t, 64, align::yes> little_uint64_buf_at;
  81. // aligned floating point buffers
  82. typedef endian_buffer<order::big, float, 32, align::yes> big_float32_buf_at;
  83. typedef endian_buffer<order::big, double, 64, align::yes> big_float64_buf_at;
  84. typedef endian_buffer<order::little, float, 32, align::yes> little_float32_buf_at;
  85. typedef endian_buffer<order::little, double, 64, align::yes> little_float64_buf_at;
  86. // aligned native endian typedefs are not provided because
  87. // <cstdint> types are superior for this use case
  88. // unaligned big endian signed integer buffers
  89. typedef endian_buffer<order::big, int_least8_t, 8> big_int8_buf_t;
  90. typedef endian_buffer<order::big, int_least16_t, 16> big_int16_buf_t;
  91. typedef endian_buffer<order::big, int_least32_t, 24> big_int24_buf_t;
  92. typedef endian_buffer<order::big, int_least32_t, 32> big_int32_buf_t;
  93. typedef endian_buffer<order::big, int_least64_t, 40> big_int40_buf_t;
  94. typedef endian_buffer<order::big, int_least64_t, 48> big_int48_buf_t;
  95. typedef endian_buffer<order::big, int_least64_t, 56> big_int56_buf_t;
  96. typedef endian_buffer<order::big, int_least64_t, 64> big_int64_buf_t;
  97. // unaligned big endian unsigned integer buffers
  98. typedef endian_buffer<order::big, uint_least8_t, 8> big_uint8_buf_t;
  99. typedef endian_buffer<order::big, uint_least16_t, 16> big_uint16_buf_t;
  100. typedef endian_buffer<order::big, uint_least32_t, 24> big_uint24_buf_t;
  101. typedef endian_buffer<order::big, uint_least32_t, 32> big_uint32_buf_t;
  102. typedef endian_buffer<order::big, uint_least64_t, 40> big_uint40_buf_t;
  103. typedef endian_buffer<order::big, uint_least64_t, 48> big_uint48_buf_t;
  104. typedef endian_buffer<order::big, uint_least64_t, 56> big_uint56_buf_t;
  105. typedef endian_buffer<order::big, uint_least64_t, 64> big_uint64_buf_t;
  106. // unaligned little endian signed integer buffers
  107. typedef endian_buffer<order::little, int_least8_t, 8> little_int8_buf_t;
  108. typedef endian_buffer<order::little, int_least16_t, 16> little_int16_buf_t;
  109. typedef endian_buffer<order::little, int_least32_t, 24> little_int24_buf_t;
  110. typedef endian_buffer<order::little, int_least32_t, 32> little_int32_buf_t;
  111. typedef endian_buffer<order::little, int_least64_t, 40> little_int40_buf_t;
  112. typedef endian_buffer<order::little, int_least64_t, 48> little_int48_buf_t;
  113. typedef endian_buffer<order::little, int_least64_t, 56> little_int56_buf_t;
  114. typedef endian_buffer<order::little, int_least64_t, 64> little_int64_buf_t;
  115. // unaligned little endian unsigned integer buffers
  116. typedef endian_buffer<order::little, uint_least8_t, 8> little_uint8_buf_t;
  117. typedef endian_buffer<order::little, uint_least16_t, 16> little_uint16_buf_t;
  118. typedef endian_buffer<order::little, uint_least32_t, 24> little_uint24_buf_t;
  119. typedef endian_buffer<order::little, uint_least32_t, 32> little_uint32_buf_t;
  120. typedef endian_buffer<order::little, uint_least64_t, 40> little_uint40_buf_t;
  121. typedef endian_buffer<order::little, uint_least64_t, 48> little_uint48_buf_t;
  122. typedef endian_buffer<order::little, uint_least64_t, 56> little_uint56_buf_t;
  123. typedef endian_buffer<order::little, uint_least64_t, 64> little_uint64_buf_t;
  124. // unaligned native endian signed integer buffers
  125. typedef endian_buffer<order::native, int_least8_t, 8> native_int8_buf_t;
  126. typedef endian_buffer<order::native, int_least16_t, 16> native_int16_buf_t;
  127. typedef endian_buffer<order::native, int_least32_t, 24> native_int24_buf_t;
  128. typedef endian_buffer<order::native, int_least32_t, 32> native_int32_buf_t;
  129. typedef endian_buffer<order::native, int_least64_t, 40> native_int40_buf_t;
  130. typedef endian_buffer<order::native, int_least64_t, 48> native_int48_buf_t;
  131. typedef endian_buffer<order::native, int_least64_t, 56> native_int56_buf_t;
  132. typedef endian_buffer<order::native, int_least64_t, 64> native_int64_buf_t;
  133. // unaligned native endian unsigned integer buffers
  134. typedef endian_buffer<order::native, uint_least8_t, 8> native_uint8_buf_t;
  135. typedef endian_buffer<order::native, uint_least16_t, 16> native_uint16_buf_t;
  136. typedef endian_buffer<order::native, uint_least32_t, 24> native_uint24_buf_t;
  137. typedef endian_buffer<order::native, uint_least32_t, 32> native_uint32_buf_t;
  138. typedef endian_buffer<order::native, uint_least64_t, 40> native_uint40_buf_t;
  139. typedef endian_buffer<order::native, uint_least64_t, 48> native_uint48_buf_t;
  140. typedef endian_buffer<order::native, uint_least64_t, 56> native_uint56_buf_t;
  141. typedef endian_buffer<order::native, uint_least64_t, 64> native_uint64_buf_t;
  142. // unaligned floating point buffers
  143. typedef endian_buffer<order::big, float, 32, align::no> big_float32_buf_t;
  144. typedef endian_buffer<order::big, double, 64, align::no> big_float64_buf_t;
  145. typedef endian_buffer<order::little, float, 32, align::no> little_float32_buf_t;
  146. typedef endian_buffer<order::little, double, 64, align::no> little_float64_buf_t;
  147. typedef endian_buffer<order::native, float, 32, align::no> native_float32_buf_t;
  148. typedef endian_buffer<order::native, double, 64, align::no> native_float64_buf_t;
  149. // Stream inserter
  150. template <class charT, class traits, BOOST_SCOPED_ENUM(order) Order, class T,
  151. std::size_t n_bits, BOOST_SCOPED_ENUM(align) A>
  152. std::basic_ostream<charT, traits>&
  153. operator<<(std::basic_ostream<charT, traits>& os,
  154. const endian_buffer<Order, T, n_bits, A>& x)
  155. {
  156. return os << x.value();
  157. }
  158. // Stream extractor
  159. template <class charT, class traits, BOOST_SCOPED_ENUM(order) Order, class T,
  160. std::size_t n_bits, BOOST_SCOPED_ENUM(align) A>
  161. std::basic_istream<charT, traits>&
  162. operator>>(std::basic_istream<charT, traits>& is,
  163. endian_buffer<Order, T, n_bits, A>& x)
  164. {
  165. T i;
  166. if (is >> i)
  167. x = i;
  168. return is;
  169. }
  170. //---------------------------------- end synopsis ------------------------------------//
  171. // endian_buffer class template specializations --------------------------------------//
  172. // Specializations that represent unaligned bytes.
  173. // Taking an integer type as a parameter provides a nice way to pass both
  174. // the size and signedness of the desired integer and get the appropriate
  175. // corresponding integer type for the interface.
  176. // Q: Should endian_buffer supply "value_type operator value_type() const noexcept"?
  177. // A: No. The rationale for endian_buffers is to prevent high-cost hidden
  178. // conversions. If an implicit conversion operator is supplied, hidden conversions
  179. // can occur.
  180. // unaligned endian_buffer specialization
  181. template< BOOST_SCOPED_ENUM(order) Order, class T, std::size_t n_bits >
  182. class endian_buffer<Order, T, n_bits, align::no>
  183. {
  184. #ifdef BOOST_ENDIAN_NO_CTORS
  185. public:
  186. #endif
  187. BOOST_STATIC_ASSERT( (n_bits/8)*8 == n_bits );
  188. unsigned char value_[ n_bits / 8 ];
  189. public:
  190. typedef T value_type;
  191. #ifndef BOOST_ENDIAN_NO_CTORS
  192. endian_buffer() BOOST_ENDIAN_DEFAULT_CONSTRUCT
  193. explicit endian_buffer( T val ) BOOST_NOEXCEPT
  194. {
  195. boost::endian::endian_store<T, n_bits / 8, Order>( value_, val );
  196. }
  197. #endif
  198. endian_buffer& operator=( T val ) BOOST_NOEXCEPT
  199. {
  200. boost::endian::endian_store<T, n_bits / 8, Order>( value_, val );
  201. return *this;
  202. }
  203. value_type value() const BOOST_NOEXCEPT
  204. {
  205. return boost::endian::endian_load<T, n_bits / 8, Order>( value_ );
  206. }
  207. unsigned char const * data() const BOOST_NOEXCEPT
  208. {
  209. return value_;
  210. }
  211. unsigned char * data() BOOST_NOEXCEPT
  212. {
  213. return value_;
  214. }
  215. };
  216. // aligned specializations; only n_bits == 16/32/64 supported
  217. // aligned endian_buffer specialization
  218. template< BOOST_SCOPED_ENUM(order) Order, class T, std::size_t n_bits >
  219. class endian_buffer<Order, T, n_bits, align::yes>
  220. {
  221. private:
  222. BOOST_STATIC_ASSERT( (n_bits/8)*8 == n_bits );
  223. BOOST_STATIC_ASSERT( sizeof(T) == n_bits/8 );
  224. union
  225. {
  226. unsigned char value_[ n_bits / 8 ];
  227. T align_;
  228. };
  229. public:
  230. typedef T value_type;
  231. #ifndef BOOST_ENDIAN_NO_CTORS
  232. endian_buffer() BOOST_ENDIAN_DEFAULT_CONSTRUCT
  233. explicit endian_buffer( T val ) BOOST_NOEXCEPT
  234. {
  235. boost::endian::endian_store<T, n_bits / 8, Order>( value_, val );
  236. }
  237. #endif
  238. endian_buffer& operator=( T val ) BOOST_NOEXCEPT
  239. {
  240. boost::endian::endian_store<T, n_bits / 8, Order>( value_, val );
  241. return *this;
  242. }
  243. value_type value() const BOOST_NOEXCEPT
  244. {
  245. return boost::endian::endian_load<T, n_bits / 8, Order>( value_ );
  246. }
  247. unsigned char const * data() const BOOST_NOEXCEPT
  248. {
  249. return value_;
  250. }
  251. unsigned char * data() BOOST_NOEXCEPT
  252. {
  253. return value_;
  254. }
  255. };
  256. // aligned native endian_buffer specialization
  257. template< class T, std::size_t n_bits >
  258. class endian_buffer<order::native, T, n_bits, align::yes>
  259. {
  260. private:
  261. BOOST_STATIC_ASSERT( (n_bits/8)*8 == n_bits );
  262. BOOST_STATIC_ASSERT( sizeof(T) == n_bits/8 );
  263. T value_;
  264. public:
  265. typedef T value_type;
  266. #ifndef BOOST_ENDIAN_NO_CTORS
  267. endian_buffer() BOOST_ENDIAN_DEFAULT_CONSTRUCT
  268. explicit endian_buffer( T val ) BOOST_NOEXCEPT: value_( val )
  269. {
  270. }
  271. #endif
  272. endian_buffer& operator=( T val ) BOOST_NOEXCEPT
  273. {
  274. value_ = val;
  275. return *this;
  276. }
  277. value_type value() const BOOST_NOEXCEPT
  278. {
  279. return value_;
  280. }
  281. unsigned char const * data() const BOOST_NOEXCEPT
  282. {
  283. return reinterpret_cast< unsigned char const* >( &value_ );
  284. }
  285. unsigned char * data() BOOST_NOEXCEPT
  286. {
  287. return reinterpret_cast< unsigned char* >( &value_ );
  288. }
  289. };
  290. } // namespace endian
  291. } // namespace boost
  292. #if defined(BOOST_BORLANDC) || defined(BOOST_CODEGEARC)
  293. # pragma pack(pop)
  294. #endif
  295. #if defined(_MSC_VER)
  296. # pragma warning(pop)
  297. #endif
  298. #endif // BOOST_ENDIAN_BUFFERS_HPP