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 )
  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             rSpans.push_back(Span(nIndex1, nIndex2, nLastVal));
  65         }
  66
  67         nLastPos = nThisPos;
  68         nLastVal = nThisVal;
  69     }
  70 }
  71
  72 /**
  73  * Convert a flat_segment_tree structure whose value type is boolean, into
  74  * an array of ranges that corresponds with the segments that have a 'true'
  75  * value.
  76  */
  77 template<typename Key, typename Span>
  78 std::vector<Span> toSpanArray( const mdds::flat_segment_tree<Key,bool>& rTree )
  79 {
  80     typedef mdds::flat_segment_tree<Key,bool> FstType;
  81
  82     std::vector<Span> aSpans;
  83
  84     typename FstType::const_iterator it = rTree.begin(), itEnd = rTree.end();
  85     buildSpan<Key,Span>(aSpans, it, itEnd, nullptr);
  86     return aSpans;
  87 }
  88
  89 /**
  90  * Convert a flat_segment_tree structure into an array of ranges with
  91  * values.  Only those ranges whose value is evaluated to be true will be
  92  * included.  The value type must be something that supports bool operator.
  93  * The span type must support a constructor that takes a start key, an end
  94  * key and a value in this order.
  95  */
  96 template<typename Key, typename Val, typename Span>
  97 std::vector<Span> toSpanArrayWithValue( const mdds::flat_segment_tree<Key,Val>& rTree )
  98 {
  99     typedef mdds::flat_segment_tree<Key,Val> FstType;
 100
 101     std::vector<Span> aSpans;
 102
 103     typename FstType::const_iterator it = rTree.begin(), itEnd = rTree.end();
 104     buildSpanWithValue<Key,Val,Span>(aSpans, it, itEnd);
 105     return aSpans;
 106 }
 107
 108 template<typename Key, typename Span>
 109 std::vector<Span> toSpanArray( const mdds::flat_segment_tree<Key,bool>& rTree, Key nStartPos )
 110 {
 111     typedef mdds::flat_segment_tree<Key,bool> FstType;
 112
 113     std::vector<Span> aSpans;
 114     if (!rTree.is_tree_valid())
 115         return aSpans;
 116
 117     bool bThisVal = false;
 118     std::pair<typename FstType::const_iterator, bool> r =
 119         rTree.search_tree(nStartPos, bThisVal);
 120
 121     if (!r.second)
 122         // Tree search failed.
 123         return aSpans;
 124
 125     typename FstType::const_iterator it = r.first, itEnd = rTree.end();
 126     buildSpan<Key,Span>(aSpans, it, itEnd, &nStartPos);
 127     return aSpans;
 128 }
 129
 130 }
 131
 132 #endif
 133
 134 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */