Method findSequences

src/IECore/FileSequenceFunctions.cpp:87–184

using namespace IECore;

void IECore::findSequences( const std::vector< std::string > &names, std::vector< FileSequencePtr > &sequences, size_t minSequenceSize )
{
	sequences.clear();

	/// this matches names of the form $prefix$frameNumber$suffix
	/// placing each of those in a group of the resulting match.
	/// both $prefix and $suffix may be the empty string and $frameNumber
	/// may be preceded by a minus sign.
	/// It also matches file extensions with 3 or 4 characters that contain numbers (for example: CR2, MP3 )
	boost::regex matchExpression( std::string( "^([^#]*?)(-?[0-9]+)([^0-9#]*|[^0-9#]*\\.[a-zA-Z]{2,3}[0-9])$" ) );

	/// build a mapping from ($prefix, $suffix) to a list of $frameNumbers
	typedef std::vector< std::string > Frames;
	typedef std::map< std::pair< std::string, std::string >, Frames > SequenceMap;

	SequenceMap sequenceMap;

	for ( std::vector< std::string >::const_iterator it = names.begin(); it != names.end(); ++it )
	{
		boost::smatch matches;
		if ( boost::regex_match( *it, matches, matchExpression ) )
		{
			sequenceMap[
				SequenceMap::key_type(
					std::string( matches[1].first, matches[1].second ),
					std::string( matches[3].first, matches[3].second )
				)
			].push_back( std::string( matches[2].first, matches[2].second ) );
		}
	}

	for ( SequenceMap::const_iterator it = sequenceMap.begin(); it != sequenceMap.end(); ++it )
	{
		const SequenceMap::key_type &fixes = it->first;
		const Frames &frames = it->second;
		// todo: could be more efficient by writing a custom comparison function that uses indexes
		//	 into the const Frames vector rather than duplicating the strings and sorting them directly
		Frames sortedFrames = frames;
		std::sort( sortedFrames.begin(), sortedFrames.end() );

		/// in diabolical cases the elements of frames may not all have the same padding
		/// so we'll sort them out into padded and unpadded frame sequences here, by creating
		/// a map of padding->list of frames. unpadded things will be considered to have a padding
		/// of 1.
		typedef std::vector< FrameList::Frame > NumericFrames;
		typedef std::map< unsigned int, NumericFrames > PaddingToFramesMap;
		PaddingToFramesMap paddingToFrames;
		for ( Frames::const_iterator fIt = sortedFrames.begin(); fIt != sortedFrames.end(); ++fIt )
		{
			std::string frame = *fIt;
			int sign = 1;

			assert( frame.size() );
			if ( *frame.begin() == '-' )
			{
				frame = frame.substr( 1, frame.size() - 1 );
				sign = -1;
			}