range_return.hpp 6.0 KB

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  1. // Copyright Neil Groves 2009. Use, modification and
  2. // distribution is subject to the Boost Software License, Version
  3. // 1.0. (See accompanying file LICENSE_1_0.txt or copy at
  4. // http://www.boost.org/LICENSE_1_0.txt)
  5. //
  6. //
  7. // For more information, see http://www.boost.org/libs/range/
  8. //
  9. #ifndef BOOST_RANGE_DETAIL_RANGE_RETURN_HPP_INCLUDED
  10. #define BOOST_RANGE_DETAIL_RANGE_RETURN_HPP_INCLUDED
  11. #include <boost/range/begin.hpp>
  12. #include <boost/range/end.hpp>
  13. #include <boost/range/iterator_range.hpp>
  14. #include <boost/next_prior.hpp>
  15. namespace boost
  16. {
  17. enum range_return_value
  18. {
  19. // (*) indicates the most common values
  20. return_found, // only the found resulting iterator (*)
  21. return_next, // next(found) iterator
  22. return_prior, // prior(found) iterator
  23. return_begin_found, // [begin, found) range (*)
  24. return_begin_next, // [begin, next(found)) range
  25. return_begin_prior, // [begin, prior(found)) range
  26. return_found_end, // [found, end) range (*)
  27. return_next_end, // [next(found), end) range
  28. return_prior_end, // [prior(found), end) range
  29. return_begin_end // [begin, end) range
  30. };
  31. template< class SinglePassRange, range_return_value >
  32. struct range_return
  33. {
  34. typedef boost::iterator_range<
  35. BOOST_DEDUCED_TYPENAME range_iterator<SinglePassRange>::type > type;
  36. static type pack(BOOST_DEDUCED_TYPENAME range_iterator<SinglePassRange>::type found,
  37. SinglePassRange& rng)
  38. {
  39. return type(found, boost::end(rng));
  40. }
  41. };
  42. template< class SinglePassRange >
  43. struct range_return< SinglePassRange, return_found >
  44. {
  45. typedef BOOST_DEDUCED_TYPENAME range_iterator<SinglePassRange>::type type;
  46. static type pack(type found, SinglePassRange&)
  47. {
  48. return found;
  49. }
  50. };
  51. template< class SinglePassRange >
  52. struct range_return< SinglePassRange, return_next >
  53. {
  54. typedef BOOST_DEDUCED_TYPENAME range_iterator<SinglePassRange>::type type;
  55. static type pack(type found, SinglePassRange& rng)
  56. {
  57. return found == boost::end(rng)
  58. ? found
  59. : boost::next(found);
  60. }
  61. };
  62. template< class BidirectionalRange >
  63. struct range_return< BidirectionalRange, return_prior >
  64. {
  65. typedef BOOST_DEDUCED_TYPENAME range_iterator<BidirectionalRange>::type type;
  66. static type pack(type found, BidirectionalRange& rng)
  67. {
  68. return found == boost::begin(rng)
  69. ? found
  70. : boost::prior(found);
  71. }
  72. };
  73. template< class SinglePassRange >
  74. struct range_return< SinglePassRange, return_begin_found >
  75. {
  76. typedef boost::iterator_range<
  77. BOOST_DEDUCED_TYPENAME range_iterator<SinglePassRange>::type > type;
  78. static type pack(BOOST_DEDUCED_TYPENAME range_iterator<SinglePassRange>::type found,
  79. SinglePassRange& rng)
  80. {
  81. return type(boost::begin(rng), found);
  82. }
  83. };
  84. template< class SinglePassRange >
  85. struct range_return< SinglePassRange, return_begin_next >
  86. {
  87. typedef boost::iterator_range<
  88. BOOST_DEDUCED_TYPENAME range_iterator<SinglePassRange>::type > type;
  89. static type pack(BOOST_DEDUCED_TYPENAME range_iterator<SinglePassRange>::type found,
  90. SinglePassRange& rng)
  91. {
  92. return type( boost::begin(rng),
  93. found == boost::end(rng) ? found : boost::next(found) );
  94. }
  95. };
  96. template< class BidirectionalRange >
  97. struct range_return< BidirectionalRange, return_begin_prior >
  98. {
  99. typedef boost::iterator_range<
  100. BOOST_DEDUCED_TYPENAME range_iterator<BidirectionalRange>::type > type;
  101. static type pack(BOOST_DEDUCED_TYPENAME range_iterator<BidirectionalRange>::type found,
  102. BidirectionalRange& rng)
  103. {
  104. return type( boost::begin(rng),
  105. found == boost::begin(rng) ? found : boost::prior(found) );
  106. }
  107. };
  108. template< class SinglePassRange >
  109. struct range_return< SinglePassRange, return_found_end >
  110. {
  111. typedef boost::iterator_range<
  112. BOOST_DEDUCED_TYPENAME range_iterator<SinglePassRange>::type > type;
  113. static type pack(BOOST_DEDUCED_TYPENAME range_iterator<SinglePassRange>::type found,
  114. SinglePassRange& rng)
  115. {
  116. return type(found, boost::end(rng));
  117. }
  118. };
  119. template< class SinglePassRange >
  120. struct range_return< SinglePassRange, return_next_end >
  121. {
  122. typedef boost::iterator_range<
  123. BOOST_DEDUCED_TYPENAME range_iterator<SinglePassRange>::type > type;
  124. static type pack(BOOST_DEDUCED_TYPENAME range_iterator<SinglePassRange>::type found,
  125. SinglePassRange& rng)
  126. {
  127. return type( found == boost::end(rng) ? found : boost::next(found),
  128. boost::end(rng) );
  129. }
  130. };
  131. template< class BidirectionalRange >
  132. struct range_return< BidirectionalRange, return_prior_end >
  133. {
  134. typedef boost::iterator_range<
  135. BOOST_DEDUCED_TYPENAME range_iterator<BidirectionalRange>::type > type;
  136. static type pack(BOOST_DEDUCED_TYPENAME range_iterator<BidirectionalRange>::type found,
  137. BidirectionalRange& rng)
  138. {
  139. return type( found == boost::begin(rng) ? found : boost::prior(found),
  140. boost::end(rng) );
  141. }
  142. };
  143. template< class SinglePassRange >
  144. struct range_return< SinglePassRange, return_begin_end >
  145. {
  146. typedef boost::iterator_range<
  147. BOOST_DEDUCED_TYPENAME range_iterator<SinglePassRange>::type > type;
  148. static type pack(BOOST_DEDUCED_TYPENAME range_iterator<SinglePassRange>::type,
  149. SinglePassRange& rng)
  150. {
  151. return type(boost::begin(rng), boost::end(rng));
  152. }
  153. };
  154. }
  155. #endif // include guard