Function icvReadSeqTree

deps/opencv/modules/core/src/persistence.cpp:4370–4427

static void*
icvReadSeqTree( CvFileStorage* fs, CvFileNode* node )
{
    void* ptr = 0;
    CvFileNode *sequences_node = cvGetFileNodeByName( fs, node, "sequences" );
    CvSeq* sequences;
    CvSeq* root = 0;
    CvSeq* parent = 0;
    CvSeq* prev_seq = 0;
    CvSeqReader reader;
    int i, total;
    int prev_level = 0;

    if( !sequences_node || !CV_NODE_IS_SEQ(sequences_node->tag) )
        CV_Error( CV_StsParseError,
        "opencv-sequence-tree instance should contain a field \"sequences\" that should be a sequence" );

    sequences = sequences_node->data.seq;
    total = sequences->total;

    cvStartReadSeq( sequences, &reader, 0 );
    for( i = 0; i < total; i++ )
    {
        CvFileNode* elem = (CvFileNode*)reader.ptr;
        CvSeq* seq;
        int level;
        seq = (CvSeq*)cvRead( fs, elem );
        level = cvReadIntByName( fs, elem, "level", -1 );
        if( level < 0 )
            CV_Error( CV_StsParseError, "All the sequence tree nodes should contain \"level\" field" );
        if( !root )
            root = seq;
        if( level > prev_level )
        {
            assert( level == prev_level + 1 );
            parent = prev_seq;
            prev_seq = 0;
            if( parent )
                parent->v_next = seq;
        }
        else if( level < prev_level )
        {
            for( ; prev_level > level; prev_level-- )
                prev_seq = prev_seq->v_prev;
            parent = prev_seq->v_prev;
        }
        seq->h_prev = prev_seq;
        if( prev_seq )
            prev_seq->h_next = seq;
        seq->v_prev = parent;
        prev_seq = seq;
        prev_level = level;
        CV_NEXT_SEQ_ELEM( sequences->elem_size, reader );
    }

    ptr = root;
    return ptr;
}