Function icvWriteSparseMat

deps/opencv/modules/core/src/persistence.cpp:3738–3805

static void
icvWriteSparseMat( CvFileStorage* fs, const char* name,
                   const void* struct_ptr, CvAttrList /*attr*/ )
{
    CvMemStorage* memstorage = 0;
    const CvSparseMat* mat = (const CvSparseMat*)struct_ptr;
    CvSparseMatIterator iterator;
    CvSparseNode* node;
    CvSeq* elements;
    CvSeqReader reader;
    int i, dims;
    int *prev_idx = 0;
    char dt[16];

    assert( CV_IS_SPARSE_MAT(mat) );

    memstorage = cvCreateMemStorage();

    cvStartWriteStruct( fs, name, CV_NODE_MAP, CV_TYPE_NAME_SPARSE_MAT );
    dims = cvGetDims( mat, 0 );

    cvStartWriteStruct( fs, "sizes", CV_NODE_SEQ + CV_NODE_FLOW );
    cvWriteRawData( fs, mat->size, dims, "i" );
    cvEndWriteStruct( fs );
    cvWriteString( fs, "dt", icvEncodeFormat( CV_MAT_TYPE(mat->type), dt ), 0 );
    cvStartWriteStruct( fs, "data", CV_NODE_SEQ + CV_NODE_FLOW );

    elements = cvCreateSeq( CV_SEQ_ELTYPE_PTR, sizeof(CvSeq), sizeof(int*), memstorage );

    node = cvInitSparseMatIterator( mat, &iterator );
    while( node )
    {
        int* idx = CV_NODE_IDX( mat, node );
        cvSeqPush( elements, &idx );
        node = cvGetNextSparseNode( &iterator );
    }

    cvSeqSort( elements, icvSortIdxCmpFunc, &dims );
    cvStartReadSeq( elements, &reader, 0 );

    for( i = 0; i < elements->total; i++ )
    {
        int* idx;
        void* val;
        int k = 0;

        CV_READ_SEQ_ELEM( idx, reader );
        if( i > 0 )
        {
            for( ; idx[k] == prev_idx[k]; k++ )
                assert( k < dims );
            if( k < dims - 1 )
                fs->write_int( fs, 0, k - dims + 1 );
        }
        for( ; k < dims; k++ )
            fs->write_int( fs, 0, idx[k] );
        prev_idx = idx;