sliced.hpp 2.8 KB

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  1. // Boost.Range library
  2. //
  3. // Copyright Thorsten Ottosen, Neil Groves 2006 - 2008. Use, modification and
  4. // distribution is subject to the Boost Software License, Version
  5. // 1.0. (See accompanying file LICENSE_1_0.txt or copy at
  6. // http://www.boost.org/LICENSE_1_0.txt)
  7. //
  8. // For more information, see http://www.boost.org/libs/range/
  9. //
  10. #ifndef BOOST_RANGE_ADAPTOR_SLICED_HPP
  11. #define BOOST_RANGE_ADAPTOR_SLICED_HPP
  12. #include <boost/range/adaptor/argument_fwd.hpp>
  13. #include <boost/range/size_type.hpp>
  14. #include <boost/range/iterator_range.hpp>
  15. namespace boost
  16. {
  17. namespace adaptors
  18. {
  19. struct sliced
  20. {
  21. sliced(std::size_t t_, std::size_t u_)
  22. : t(t_), u(u_) {}
  23. std::size_t t;
  24. std::size_t u;
  25. };
  26. template< class RandomAccessRange >
  27. class sliced_range : public boost::iterator_range< BOOST_DEDUCED_TYPENAME range_iterator<RandomAccessRange>::type >
  28. {
  29. typedef boost::iterator_range< BOOST_DEDUCED_TYPENAME range_iterator<RandomAccessRange>::type > base_t;
  30. public:
  31. template<typename Rng, typename T, typename U>
  32. sliced_range(Rng& rng, T t, U u)
  33. : base_t(boost::make_iterator_range(rng, t, u - boost::size(rng)))
  34. {
  35. }
  36. };
  37. template< class RandomAccessRange >
  38. inline sliced_range<RandomAccessRange>
  39. slice( RandomAccessRange& rng, std::size_t t, std::size_t u )
  40. {
  41. BOOST_ASSERT( t <= u && "error in slice indices" );
  42. BOOST_ASSERT( static_cast<std::size_t>(boost::size(rng)) >= u &&
  43. "second slice index out of bounds" );
  44. return sliced_range<RandomAccessRange>(rng, t, u);
  45. }
  46. template< class RandomAccessRange >
  47. inline iterator_range< BOOST_DEDUCED_TYPENAME range_iterator<const RandomAccessRange>::type >
  48. slice( const RandomAccessRange& rng, std::size_t t, std::size_t u )
  49. {
  50. BOOST_ASSERT( t <= u && "error in slice indices" );
  51. BOOST_ASSERT( static_cast<std::size_t>(boost::size(rng)) >= u &&
  52. "second slice index out of bounds" );
  53. return sliced_range<const RandomAccessRange>(rng, t, u);
  54. }
  55. template< class RandomAccessRange >
  56. inline sliced_range<RandomAccessRange>
  57. operator|( RandomAccessRange& r, const sliced& f )
  58. {
  59. return sliced_range<RandomAccessRange>( r, f.t, f.u );
  60. }
  61. template< class RandomAccessRange >
  62. inline sliced_range<const RandomAccessRange>
  63. operator|( const RandomAccessRange& r, const sliced& f )
  64. {
  65. return sliced_range<const RandomAccessRange>( r, f.t, f.u );
  66. }
  67. } // namespace adaptors
  68. using adaptors::sliced_range;
  69. } // namespace boost
  70. #endif