Fix index overflow

Indexing very large CHM files caused the docNumber variable to overflow
and exceed the array boundaries. Increasing the size of the docNumber
and frequency variables solves this problem, but makes the old index cache
incompatible. Therefore, the version number of the index cache has been
increased.

Author: gonwan

lib/libebook/helper_search_index.cpp

@@ -36,7 +36,7 @@
 #include "helper_search_index.h"
 
 
-static const int DICT_VERSION = 4;
+static const int DICT_VERSION = 5;
 
 namespace QtAs
 {
@@ -70,8 +70,8 @@ QDataStream& operator>>( QDataStream& s, Document& l )
 
 QDataStream& operator<<( QDataStream& s, const Document& l )
 {
-	s << ( short )l.docNumber;
-	s << ( short )l.frequency;
+	s << l.docNumber;
+	s << l.frequency;
 	return s;
 }
 
@@ -347,7 +347,7 @@ void Index::writeDict( QDataStream& stream )
 	for ( QHash<QString, Entry*>::ConstIterator it = dict.begin(); it != dict.end(); ++it )
 	{
 		stream << it.key();
-		stream << ( int ) it.value()->documents.count();
+		stream << it.value()->documents.count();
 		stream << it.value()->documents;
 	}
 }
@@ -362,7 +362,7 @@ bool Index::readDict( QDataStream& stream )
 
 	stream >> version;
 
-	if ( version < 2 )
+	if ( version != DICT_VERSION )
 		return false;
 
 	stream >> m_charssplit;
@@ -424,9 +424,9 @@ QList< QUrl > Index::query( const QStringList& terms, const QStringList& termSeq
 
 			for ( QVector<Document>::ConstIterator doc_it = docs.constBegin(); doc_it != docs.constEnd(); ++doc_it )
 			{
-				if ( ( *minDoc_it ).docNumber == ( *doc_it ).docNumber )
+				if ( minDoc_it->docNumber == doc_it->docNumber )
 				{
-					( *minDoc_it ).frequency += ( *doc_it ).frequency;
+					minDoc_it->frequency += doc_it->frequency;
 					found = true;
 					break;
 				}
@@ -445,7 +445,7 @@ QList< QUrl > Index::query( const QStringList& terms, const QStringList& termSeq
 	if ( termSeq.isEmpty() )
 	{
 		for ( QVector<Document>::Iterator it = minDocs.begin(); it != minDocs.end(); ++it )
-			results << docList.at( ( int )( *it ).docNumber );
+			results << docList.at( it->docNumber );
 
 		return results;
 	}
@@ -454,7 +454,7 @@ QList< QUrl > Index::query( const QStringList& terms, const QStringList& termSeq
 
 	for ( QVector<Document>::Iterator it = minDocs.begin(); it != minDocs.end(); ++it )
 	{
-		fileName =  docList[( int )( *it ).docNumber ];
+		fileName =  docList[ it->docNumber ];
 
 		if ( searchForPhrases( termSeq, seqWords, fileName, chmFile ) )
 			results << fileName;

lib/libebook/helper_search_index.h

@@ -63,8 +63,8 @@ struct Document
 		return frequency < doc.frequency;
 	}
 
-	qint16  docNumber;
-	qint16  frequency;
+	int  docNumber;
+	int  frequency;
 };
 
 QDataStream& operator>>( QDataStream& s, Document& l );