Function cvSeqInsertSlice

deps/opencv/modules/core/src/datastructs.cpp:1745–1830

Insert a sequence into the middle of another sequence: !!! TODO !!! Implement more efficient algorithm

// Insert a sequence into the middle of another sequence:
// !!! TODO !!! Implement more efficient algorithm
CV_IMPL void
cvSeqInsertSlice( CvSeq* seq, int index, const CvArr* from_arr )
{
    CvSeqReader reader_to, reader_from;
    int i, elem_size, total, from_total;
    CvSeq from_header, *from = (CvSeq*)from_arr;
    CvSeqBlock block;

    if( !CV_IS_SEQ(seq) )
        CV_Error( CV_StsBadArg, "Invalid destination sequence header" );

    if( !CV_IS_SEQ(from))
    {
        CvMat* mat = (CvMat*)from;
        if( !CV_IS_MAT(mat))
            CV_Error( CV_StsBadArg, "Source is not a sequence nor matrix" );

        if( !CV_IS_MAT_CONT(mat->type) || (mat->rows != 1 && mat->cols != 1) )
            CV_Error( CV_StsBadArg, "The source array must be 1d coninuous vector" );

        from = cvMakeSeqHeaderForArray( CV_SEQ_KIND_GENERIC, sizeof(from_header),
                                                 CV_ELEM_SIZE(mat->type),
                                                 mat->data.ptr, mat->cols + mat->rows - 1,
                                                 &from_header, &block );
    }

    if( seq->elem_size != from->elem_size )
        CV_Error( CV_StsUnmatchedSizes,
        "Source and destination sequence element sizes are different." );

    from_total = from->total;

    if( from_total == 0 )
        return;

    total = seq->total;
    index += index < 0 ? total : 0;
    index -= index > total ? total : 0;

    if( (unsigned)index > (unsigned)total )
        CV_Error( CV_StsOutOfRange, "" );

    elem_size = seq->elem_size;

    if( index < (total >> 1) )
    {
        cvSeqPushMulti( seq, 0, from_total, 1 );

        cvStartReadSeq( seq, &reader_to );
        cvStartReadSeq( seq, &reader_from );
        cvSetSeqReaderPos( &reader_from, from_total );

        for( i = 0; i < index; i++ )
        {
            memcpy( reader_to.ptr, reader_from.ptr, elem_size );
            CV_NEXT_SEQ_ELEM( elem_size, reader_to );
            CV_NEXT_SEQ_ELEM( elem_size, reader_from );
        }