fdo#55315 Added simple Trie lookup tree for autocomplete words storage

Added simple Trie lookup tree which is more tailored to what is needed
in autocomplete implementation, but still has the speed of the
LatinLookupTree that has been used till now. As the implementation
is much simpler it should be more managable and easier fixable.

For now two actions: insert (word) and findSuggestions are supported.
Acttion findSuggestion returns all words in a list for a searched
sub-word, it also fixes fdo#62945.

Change-Id: I63b69c30d28b4e1c465c2122ebc537f7f75a033a
Reviewed-on: https://gerrit.libreoffice.org/4237
Reviewed-by: Michael Stahl <mstahl@redhat.com>
Tested-by: Michael Stahl <mstahl@redhat.com>

3 files changed, 275 insertions, 4 deletions

diff --git a/editeng/Library_editeng.mk b/editeng/Library_editeng.mk
index f352113c96ef..e9c5b4bea2d2 100644
--- a/editeng/Library_editeng.mk
+++ b/editeng/Library_editeng.mk
@@ -116,6 +116,7 @@ $(eval $(call gb_Library_add_exception_objects,editeng,\
     editeng/source/lookuptree/LatinLookupTree \
     editeng/source/lookuptree/LatinTreeNode \
     editeng/source/lookuptree/Node \
+    editeng/source/lookuptree/Trie \
 ))
 
 # add libraries to be linked to editeng; again these names need to be given as
diff --git a/editeng/qa/lookuptree/lookuptree_test.cxx b/editeng/qa/lookuptree/lookuptree_test.cxx
index c8ee1ab0e558..4722bb16d278 100644
--- a/editeng/qa/lookuptree/lookuptree_test.cxx
+++ b/editeng/qa/lookuptree/lookuptree_test.cxx
@@ -25,21 +25,25 @@
 #include <editeng/LookupTree.hxx>
 #include <editeng/LatinLookupTree.hxx>
 
+#include <editeng/Trie.hxx>
+
 namespace {
 
 class LookupTreeTest : public CppUnit::TestFixture
 {
-    public:
-        void test();
+public:
+    void testLookupTree();
+    void testTrie();
 
     CPPUNIT_TEST_SUITE(LookupTreeTest);
-    CPPUNIT_TEST(test);
+    CPPUNIT_TEST(testLookupTree);
+    CPPUNIT_TEST(testTrie);
     CPPUNIT_TEST_SUITE_END();
 };
 
 CPPUNIT_TEST_SUITE_REGISTRATION(LookupTreeTest);
 
-void LookupTreeTest::test()
+void LookupTreeTest::testLookupTree()
 {
     LookupTree* a = new LatinLookupTree( "a" );
 
@@ -218,6 +222,89 @@ void LookupTreeTest::test()
     delete a;
 }
 
+void LookupTreeTest::testTrie()
+{
+    editeng::Trie trie;
+    std::vector<OUString> suggestions;
+
+    trie.findSuggestions( OUString(""), suggestions);
+    CPPUNIT_ASSERT_EQUAL( (size_t) 0, suggestions.size() );
+
+    trie.insert( OUString("") );
+    trie.findSuggestions( OUString(""), suggestions);
+    CPPUNIT_ASSERT_EQUAL( (size_t) 0, suggestions.size() );
+
+    trie.findSuggestions( OUString("a"), suggestions);
+    CPPUNIT_ASSERT_EQUAL( (size_t) 0, suggestions.size() );
+
+    trie.insert( OUString("abc") );
+    trie.insert( OUString("abcdefghijklmnopqrstuvwxyz") );
+    trie.findSuggestions( OUString("a"), suggestions);
+    CPPUNIT_ASSERT_EQUAL( (size_t) 2, suggestions.size() );
+    CPPUNIT_ASSERT_EQUAL( OUString("abc"), suggestions[0] );
+    CPPUNIT_ASSERT_EQUAL( OUString("abcdefghijklmnopqrstuvwxyz"), suggestions[1] );
+    suggestions.clear();
+
+    trie.findSuggestions( OUString("abc"), suggestions);
+    CPPUNIT_ASSERT_EQUAL( (size_t) 1, suggestions.size() );
+    CPPUNIT_ASSERT_EQUAL( OUString("abcdefghijklmnopqrstuvwxyz"), suggestions[0] );
+    suggestions.clear();
+
+    trie.findSuggestions( OUString("abe"), suggestions);
+    CPPUNIT_ASSERT_EQUAL( (size_t) 0, suggestions.size() );
+    suggestions.clear();
+
+    trie.insert( OUString("abe") );
+    trie.findSuggestions( OUString(""), suggestions);
+    CPPUNIT_ASSERT_EQUAL( (size_t) 3, suggestions.size() );
+    CPPUNIT_ASSERT_EQUAL( OUString("abc"), suggestions[0] );
+    CPPUNIT_ASSERT_EQUAL( OUString("abcdefghijklmnopqrstuvwxyz"), suggestions[1] );
+    CPPUNIT_ASSERT_EQUAL( OUString("abe"), suggestions[2] );
+    suggestions.clear();
+
+    trie.insert( OUString("H31l0") );
+    trie.findSuggestions( OUString("H"), suggestions);
+
+    CPPUNIT_ASSERT_EQUAL( (size_t) 1, suggestions.size() );
+    CPPUNIT_ASSERT_EQUAL( OUString("H31l0"), suggestions[0] );
+    suggestions.clear();
+
+    trie.insert( OUString("H1") );
+    trie.findSuggestions( OUString("H"), suggestions);
+    CPPUNIT_ASSERT_EQUAL( (size_t) 2, suggestions.size() );
+    CPPUNIT_ASSERT_EQUAL( OUString("H31l0"), suggestions[0] );
+    CPPUNIT_ASSERT_EQUAL( OUString("H1"), suggestions[1] );
+    suggestions.clear();
+
+    trie.findSuggestions( OUString("H3"), suggestions);
+    CPPUNIT_ASSERT_EQUAL( (size_t) 1, suggestions.size() );
+    CPPUNIT_ASSERT_EQUAL( OUString("H31l0"), suggestions[0] );
+    suggestions.clear();
+
+    trie.insert( OStringToOUString( "H\xC3\xA4llo", RTL_TEXTENCODING_UTF8 ) );
+    trie.findSuggestions( OUString("H"), suggestions );
+    CPPUNIT_ASSERT_EQUAL( (size_t) 3, suggestions.size() );
+    CPPUNIT_ASSERT_EQUAL( OUString("H31l0"), suggestions[0] );
+    CPPUNIT_ASSERT_EQUAL( OUString("H1"), suggestions[1] );
+    CPPUNIT_ASSERT_EQUAL( OStringToOUString( "H\xC3\xA4llo", RTL_TEXTENCODING_UTF8 ), suggestions[2] );
+    suggestions.clear();
+
+    trie.findSuggestions( OUString("H3"), suggestions );
+    CPPUNIT_ASSERT_EQUAL( (size_t) 1, suggestions.size() );
+    CPPUNIT_ASSERT_EQUAL( OUString("H31l0"), suggestions[0] );
+    suggestions.clear();
+
+    trie.findSuggestions( OStringToOUString("H\xC3\xA4", RTL_TEXTENCODING_UTF8), suggestions );
+    CPPUNIT_ASSERT_EQUAL( (size_t) 1, suggestions.size() );
+    CPPUNIT_ASSERT_EQUAL( OStringToOUString("H\xC3\xA4llo", RTL_TEXTENCODING_UTF8), suggestions[0] );
+    suggestions.clear();
+
+    trie.findSuggestions( OUString(""), suggestions);
+    CPPUNIT_ASSERT_EQUAL( (size_t) 6, suggestions.size() );
+    suggestions.clear();
+
+}
+
 } // namespace end
 
 CPPUNIT_PLUGIN_IMPLEMENT();
diff --git a/editeng/source/lookuptree/Trie.cxx b/editeng/source/lookuptree/Trie.cxx
new file mode 100644
index 000000000000..30ee0be0769f
--- /dev/null
+++ b/editeng/source/lookuptree/Trie.cxx
@@ -0,0 +1,183 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+#include <editeng/Trie.hxx>
+
+namespace editeng
+{
+
+using namespace std;
+
+/* TrieNode */
+
+TrieNode::TrieNode(sal_Unicode aCharacter) :
+    mCharacter(aCharacter),
+    mMarker(false)
+{
+    for (int i=0; i<LATIN_ARRAY_SIZE; i++)
+    {
+        mLatinArray[i] = NULL;
+    }
+}
+
+TrieNode::~TrieNode()
+{
+    vector<TrieNode*>::iterator iNode;
+    for(iNode = mChildren.begin(); iNode != mChildren.end(); iNode++)
+    {
+        delete *iNode;
+    }
+
+    for (int i=0; i<LATIN_ARRAY_SIZE; i++)
+    {
+        delete mLatinArray[i];
+    }
+}
+
+void TrieNode::markWord()
+{
+    mMarker = true;
+}
+
+void TrieNode::addNewChild(TrieNode* pChild)
+{
+    if (pChild->mCharacter >= sal_Unicode('a') &&
+        pChild->mCharacter <= sal_Unicode('z'))
+    {
+        mLatinArray[pChild->mCharacter - sal_Unicode('a')] = pChild;
+    }
+    else
+    {
+        mChildren.push_back(pChild);
+    }
+}
+
+TrieNode* TrieNode::findChild(sal_Unicode aInputCharacter)
+{
+    if (aInputCharacter >= sal_Unicode('a') &&
+        aInputCharacter <= sal_Unicode('z'))
+    {
+        return mLatinArray[aInputCharacter - sal_Unicode('a')];
+    }
+
+    vector<TrieNode*>::iterator iNode;
+
+    for(iNode = mChildren.begin(); iNode != mChildren.end(); iNode++)
+    {
+        TrieNode* pCurrent = *iNode;
+        if ( pCurrent->mCharacter == aInputCharacter )
+            return pCurrent;
+    }
+
+    return NULL;
+}
+
+void TrieNode::collectSuggestions(OUString sPath, vector<OUString>& rSuggestionList)
+{
+    // first traverse nodes for alphabet characters
+    for (int i=0; i<LATIN_ARRAY_SIZE; i++)
+    {
+        TrieNode* pCurrent = mLatinArray[i];
+        if (pCurrent != NULL)
+        {
+            OUString aStringPath = sPath + OUString(pCurrent->mCharacter);
+            if(pCurrent->mMarker)
+                rSuggestionList.push_back(aStringPath);
+            // recursivly traverse tree
+            pCurrent->collectSuggestions(aStringPath, rSuggestionList);
+        }
+    }
+
+    // traverse nodes for other characters
+    vector<TrieNode*>::iterator iNode;
+    for(iNode = mChildren.begin(); iNode != mChildren.end(); iNode++)
+    {
+        TrieNode* pCurrent = *iNode;
+        if (pCurrent != NULL)
+        {
+            OUString aStringPath = sPath + OUString(pCurrent->mCharacter);
+            if(pCurrent->mMarker)
+                rSuggestionList.push_back(aStringPath);
+            // recursivly traverse tree
+            pCurrent->collectSuggestions(aStringPath, rSuggestionList);
+        }
+    }
+}
+
+TrieNode* TrieNode::traversePath(OUString sPath)
+{
+    TrieNode* pCurrent = this;
+
+    for ( sal_Int32 i = 0; i < sPath.getLength(); i++ )
+    {
+        sal_Unicode aCurrentChar = sPath[i];
+        pCurrent = pCurrent->findChild(aCurrentChar);
+        if ( pCurrent == NULL )
+            return NULL;
+    }
+
+    return pCurrent;
+}
+
+/* TRIE */
+
+Trie::Trie()
+{
+    mRoot = new TrieNode();
+}
+
+Trie::~Trie()
+{
+    delete mRoot;
+}
+
+void Trie::insert(OUString sInputString) const
+{
+    // adding an empty word is not allowed
+    if ( sInputString.isEmpty() )
+    {
+        return;
+    }
+
+    // traverse the input string and modify the tree with new nodes / characters
+
+    TrieNode* pCurrent = mRoot;
+    sal_Unicode aCurrentChar;
+
+    for ( sal_Int32 i = 0; i < sInputString.getLength(); i++ )
+    {
+        aCurrentChar = sInputString[i];
+        TrieNode* pChild = pCurrent->findChild(aCurrentChar);
+        if ( pChild == NULL )
+        {
+            TrieNode* pNewNode = new TrieNode(aCurrentChar);
+            pCurrent->addNewChild(pNewNode);
+            pCurrent = pNewNode;
+        }
+        else
+        {
+            pCurrent = pChild;
+        }
+    }
+
+    pCurrent->markWord();
+}
+
+void Trie::findSuggestions(OUString sWordPart, vector<OUString>& rSuggesstionList) const
+{
+    TrieNode* pNode = mRoot->traversePath(sWordPart);
+
+    if (pNode != NULL)
+    {
+        pNode->collectSuggestions(sWordPart, rSuggesstionList);
+    }
+}
+
+}
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */