| [29] | 1 | // Boost integer/integer_mask.hpp header file ------------------------------// |
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| 2 | |
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| 3 | // (C) Copyright Daryle Walker 2001. |
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| 4 | // Distributed under the Boost Software License, Version 1.0. (See |
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| 5 | // accompanying file LICENSE_1_0.txt or copy at |
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| 6 | // http://www.boost.org/LICENSE_1_0.txt) |
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| 7 | |
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| 8 | // See http://www.boost.org for updates, documentation, and revision history. |
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| 9 | |
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| 10 | #ifndef BOOST_INTEGER_INTEGER_MASK_HPP |
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| 11 | #define BOOST_INTEGER_INTEGER_MASK_HPP |
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| 12 | |
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| 13 | #include <boost/integer_fwd.hpp> // self include |
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| 14 | |
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| 15 | #include <boost/config.hpp> // for BOOST_STATIC_CONSTANT |
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| 16 | #include <boost/integer.hpp> // for boost::uint_t |
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| 17 | |
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| 18 | #include <climits> // for UCHAR_MAX, etc. |
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| 19 | #include <cstddef> // for std::size_t |
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| 20 | |
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| 21 | #include <boost/limits.hpp> // for std::numeric_limits |
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| 22 | |
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| 23 | |
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| 24 | namespace boost |
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| 25 | { |
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| 26 | |
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| 27 | |
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| 28 | // Specified single-bit mask class declaration -----------------------------// |
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| 29 | // (Lowest bit starts counting at 0.) |
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| 30 | |
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| 31 | template < std::size_t Bit > |
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| 32 | struct high_bit_mask_t |
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| 33 | { |
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| 34 | typedef typename uint_t<(Bit + 1)>::least least; |
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| 35 | typedef typename uint_t<(Bit + 1)>::fast fast; |
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| 36 | |
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| 37 | BOOST_STATIC_CONSTANT( least, high_bit = (least( 1u ) << Bit) ); |
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| 38 | BOOST_STATIC_CONSTANT( fast, high_bit_fast = (fast( 1u ) << Bit) ); |
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| 39 | |
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| 40 | BOOST_STATIC_CONSTANT( std::size_t, bit_position = Bit ); |
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| 41 | |
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| 42 | }; // boost::high_bit_mask_t |
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| 43 | |
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| 44 | |
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| 45 | // Specified bit-block mask class declaration ------------------------------// |
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| 46 | // Makes masks for the lowest N bits |
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| 47 | // (Specializations are needed when N fills up a type.) |
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| 48 | |
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| 49 | template < std::size_t Bits > |
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| 50 | struct low_bits_mask_t |
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| 51 | { |
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| 52 | typedef typename uint_t<Bits>::least least; |
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| 53 | typedef typename uint_t<Bits>::fast fast; |
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| 54 | |
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| 55 | BOOST_STATIC_CONSTANT( least, sig_bits = (~( ~(least( 0u )) << Bits )) ); |
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| 56 | BOOST_STATIC_CONSTANT( fast, sig_bits_fast = fast(sig_bits) ); |
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| 57 | |
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| 58 | BOOST_STATIC_CONSTANT( std::size_t, bit_count = Bits ); |
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| 59 | |
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| 60 | }; // boost::low_bits_mask_t |
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| 61 | |
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| 62 | |
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| 63 | #define BOOST_LOW_BITS_MASK_SPECIALIZE( Type ) \ |
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| 64 | template < > struct low_bits_mask_t< std::numeric_limits<Type>::digits > { \ |
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| 65 | typedef std::numeric_limits<Type> limits_type; \ |
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| 66 | typedef uint_t<limits_type::digits>::least least; \ |
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| 67 | typedef uint_t<limits_type::digits>::fast fast; \ |
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| 68 | BOOST_STATIC_CONSTANT( least, sig_bits = (~( least(0u) )) ); \ |
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| 69 | BOOST_STATIC_CONSTANT( fast, sig_bits_fast = fast(sig_bits) ); \ |
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| 70 | BOOST_STATIC_CONSTANT( std::size_t, bit_count = limits_type::digits ); \ |
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| 71 | } |
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| 72 | |
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| 73 | BOOST_LOW_BITS_MASK_SPECIALIZE( unsigned char ); |
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| 74 | |
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| 75 | #if USHRT_MAX > UCHAR_MAX |
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| 76 | BOOST_LOW_BITS_MASK_SPECIALIZE( unsigned short ); |
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| 77 | #endif |
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| 78 | |
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| 79 | #if UINT_MAX > USHRT_MAX |
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| 80 | BOOST_LOW_BITS_MASK_SPECIALIZE( unsigned int ); |
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| 81 | #endif |
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| 82 | |
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| 83 | #if ULONG_MAX > UINT_MAX |
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| 84 | BOOST_LOW_BITS_MASK_SPECIALIZE( unsigned long ); |
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| 85 | #endif |
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| 86 | |
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| 87 | #undef BOOST_LOW_BITS_MASK_SPECIALIZE |
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| 88 | |
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| 89 | |
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| 90 | } // namespace boost |
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| 91 | |
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| 92 | |
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| 93 | #endif // BOOST_INTEGER_INTEGER_MASK_HPP |
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