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 #pragma once
  11
  12 #include <mdds/flat_segment_tree.hpp>
  13 #include <vector>
  14
  15 namespace sc {
  16
  17 template<typename Key, typename Span>
  18 void buildSpan(
  19     std::vector<Span>& rSpans,
  20     typename mdds::flat_segment_tree<Key,bool>::const_iterator it,
  21     typename mdds::flat_segment_tree<Key,bool>::const_iterator itEnd, const Key* pStart )
  22 {
  23     Key nLastPos = it->first;
  24     bool bLastVal = it->second;
  25     for (++it; it != itEnd; ++it)
  26     {
  27         Key nThisPos = it->first;
  28         bool bThisVal = it->second;
  29
  30         if (bLastVal)
  31         {
  32             Key nIndex1 = nLastPos;
  33             Key nIndex2 = nThisPos-1;
  34
  35             if (!pStart || *pStart < nIndex1)
  36                 rSpans.push_back(Span(nIndex1, nIndex2));
  37             else if (*pStart <= nIndex2)
  38                 rSpans.push_back(Span(*pStart, nIndex2));
  39         }
  40
  41         nLastPos = nThisPos;
  42         bLastVal = bThisVal;
  43     }
  44 }
  45
  46 template<typename Key, typename Val, typename Span>
  47 void buildSpanWithValue(
  48     std::vector<Span>& rSpans,
  49     typename mdds::flat_segment_tree<Key,Val>::const_iterator it,
  50     typename mdds::flat_segment_tree<Key,Val>::const_iterator itEnd )
  51 {
  52     Key nLastPos = it->first;
  53     Val nLastVal = it->second;
  54     for (++it; it != itEnd; ++it)
  55     {
  56         Key nThisPos = it->first;
  57         Val nThisVal = it->second;
  58
  59         if (nLastVal)
  60         {
  61             Key nIndex1 = nLastPos;
  62             Key nIndex2 = nThisPos-1;
  63             rSpans.push_back(Span(nIndex1, nIndex2, nLastVal));
  64         }
  65
  66         nLastPos = nThisPos;
  67         nLastVal = nThisVal;
  68     }
  69 }
  70
  71 /**
  72  * Convert a flat_segment_tree structure whose value type is boolean, into
  73  * an array of ranges that corresponds with the segments that have a 'true'
  74  * value.
  75  */
  76 template<typename Key, typename Span>
  77 std::vector<Span> toSpanArray( const mdds::flat_segment_tree<Key,bool>& rTree )
  78 {
  79     typedef mdds::flat_segment_tree<Key,bool> FstType;
  80
  81     std::vector<Span> aSpans;
  82
  83     typename FstType::const_iterator it = rTree.begin(), itEnd = rTree.end();
  84     buildSpan<Key,Span>(aSpans, it, itEnd, nullptr);
  85     return aSpans;
  86 }
  87
  88 /**
  89  * Convert a flat_segment_tree structure into an array of ranges with
  90  * values.  Only those ranges whose value is evaluated to be true will be
  91  * included.  The value type must be something that supports bool operator.
  92  * The span type must support a constructor that takes a start key, an end
  93  * key and a value in this order.
  94  */
  95 template<typename Key, typename Val, typename Span>
  96 std::vector<Span> toSpanArrayWithValue( const mdds::flat_segment_tree<Key,Val>& rTree )
  97 {
  98     typedef mdds::flat_segment_tree<Key,Val> FstType;
  99
 100     std::vector<Span> aSpans;
 101
 102     typename FstType::const_iterator it = rTree.begin(), itEnd = rTree.end();
 103     buildSpanWithValue<Key,Val,Span>(aSpans, it, itEnd);
 104     return aSpans;
 105 }
 106
 107 template<typename Key, typename Span>
 108 std::vector<Span> toSpanArray( const mdds::flat_segment_tree<Key,bool>& rTree, Key nStartPos )
 109 {
 110     typedef mdds::flat_segment_tree<Key,bool> FstType;
 111
 112     std::vector<Span> aSpans;
 113     if (!rTree.is_tree_valid())
 114         return aSpans;
 115
 116     bool bThisVal = false;
 117     std::pair<typename FstType::const_iterator, bool> r =
 118         rTree.search_tree(nStartPos, bThisVal);
 119
 120     if (!r.second)
 121         // Tree search failed.
 122         return aSpans;
 123
 124     typename FstType::const_iterator it = r.first, itEnd = rTree.end();
 125     buildSpan<Key,Span>(aSpans, it, itEnd, &nStartPos);
 126     return aSpans;
 127 }
 128
 129 }
 130
 131 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */