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