sc/inc/fstalgorithm.hxx

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
   2 /*
   3  * This file is part of the LibreOffice project.
   4  *
   5  * This Source Code Form is subject to the terms of the Mozilla Public
   6  * License, v. 2.0. If a copy of the MPL was not distributed with this
   7  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
   8  */
   9
  10 #ifndef INCLUDED_SC_INC_FSTALGORITHM_HXX
  11 #define INCLUDED_SC_INC_FSTALGORITHM_HXX
  12
  13 #include <mdds/flat_segment_tree.hpp>
  14 #include <vector>
  15
  16 namespace sc {
  17
  18 template<typename Key, typename Span>
  19 void buildSpan(
  20     std::vector<Span>& rSpans,
  21     typename mdds::flat_segment_tree<Key,bool>::const_iterator it,
  22     typename mdds::flat_segment_tree<Key,bool>::const_iterator itEnd, const Key* pStart )
  23 {
  24     Key nLastPos = it->first;
  25     bool bLastVal = it->second;
  26     for (++it; it != itEnd; ++it)
  27     {
  28         Key nThisPos = it->first;
  29         bool bThisVal = it->second;
  30
  31         if (bLastVal)
  32         {
  33             Key nIndex1 = nLastPos;
  34             Key nIndex2 = nThisPos-1;
  35
  36             if (!pStart || *pStart < nIndex1)
  37                 rSpans.push_back(Span(nIndex1, nIndex2));
  38             else if (*pStart <= nIndex2)
  39                 rSpans.push_back(Span(*pStart, nIndex2));
  40         }
  41
  42         nLastPos = nThisPos;
  43         bLastVal = bThisVal;
  44     }
  45 }
  46
  47 template<typename Key, typename Val, typename Span>
  48 void buildSpanWithValue(
  49     std::vector<Span>& rSpans,
  50     typename mdds::flat_segment_tree<Key,Val>::const_iterator it,
  51     typename mdds::flat_segment_tree<Key,Val>::const_iterator itEnd, const Key* pStart )
  52 {
  53     Key nLastPos = it->first;
  54     Val nLastVal = it->second;
  55     for (++it; it != itEnd; ++it)
  56     {
  57         Key nThisPos = it->first;
  58         Val nThisVal = it->second;
  59
  60         if (nLastVal)
  61         {
  62             Key nIndex1 = nLastPos;
  63             Key nIndex2 = nThisPos-1;
  64
  65             if (!pStart || *pStart < nIndex1)
  66                 rSpans.push_back(Span(nIndex1, nIndex2, nLastVal));
  67             else if (*pStart <= nIndex2)
  68                 rSpans.push_back(Span(*pStart, nIndex2, nLastVal));
  69         }
  70
  71         nLastPos = nThisPos;
  72         nLastVal = nThisVal;
  73     }
  74 }
  75
  76 /**
  77  * Convert a flat_segment_tree structure whose value type is boolean, into
  78  * an array of ranges that corresponds with the segments that have a 'true'
  79  * value.
  80  */
  81 template<typename Key, typename Span>
  82 std::vector<Span> toSpanArray( const mdds::flat_segment_tree<Key,bool>& rTree )
  83 {
  84     typedef mdds::flat_segment_tree<Key,bool> FstType;
  85
  86     std::vector<Span> aSpans;
  87
  88     typename FstType::const_iterator it = rTree.begin(), itEnd = rTree.end();
  89     buildSpan<Key,Span>(aSpans, it, itEnd, nullptr);
  90     return aSpans;
  91 }
  92
  93 /**
  94  * Convert a flat_segment_tree structure into an array of ranges with
  95  * values.  Only those ranges whose value is evaluated to be true will be
  96  * included.  The value type must be something that supports bool operator.
  97  * The span type must support a constructor that takes a start key, an end
  98  * key and a value in this order.
  99  */
 100 template<typename Key, typename Val, typename Span>
 101 std::vector<Span> toSpanArrayWithValue( const mdds::flat_segment_tree<Key,Val>& rTree )
 102 {
 103     typedef mdds::flat_segment_tree<Key,Val> FstType;
 104
 105     std::vector<Span> aSpans;
 106
 107     typename FstType::const_iterator it = rTree.begin(), itEnd = rTree.end();
 108     buildSpanWithValue<Key,Val,Span>(aSpans, it, itEnd, nullptr);
 109     return aSpans;
 110 }
 111
 112 template<typename Key, typename Span>
 113 std::vector<Span> toSpanArray( const mdds::flat_segment_tree<Key,bool>& rTree, Key nStartPos )
 114 {
 115     typedef mdds::flat_segment_tree<Key,bool> FstType;
 116
 117     std::vector<Span> aSpans;
 118     if (!rTree.is_tree_valid())
 119         return aSpans;
 120
 121     bool bThisVal = false;
 122     std::pair<typename FstType::const_iterator, bool> r =
 123         rTree.search_tree(nStartPos, bThisVal);
 124
 125     if (!r.second)
 126         // Tree search failed.
 127         return aSpans;
 128
 129     typename FstType::const_iterator it = r.first, itEnd = rTree.end();
 130     buildSpan<Key,Span>(aSpans, it, itEnd, &nStartPos);
 131     return aSpans;
 132 }
 133
 134 }
 135
 136 #endif
 137
 138 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */