Function cvMakeSeqHeaderForArray

deps/opencv/modules/core/src/datastructs.cpp:577–619

Construct a sequence from an array without copying any data. NB: The resultant sequence cannot grow beyond its initial size: */

/* Construct a sequence from an array without copying any data.
   NB: The resultant sequence cannot grow beyond its initial size: */
CV_IMPL CvSeq*
cvMakeSeqHeaderForArray( int seq_flags, int header_size, int elem_size,
                         void *array, int total, CvSeq *seq, CvSeqBlock * block )
{
    CvSeq* result = 0;

    if( elem_size <= 0 || header_size < (int)sizeof( CvSeq ) || total < 0 )
        CV_Error( CV_StsBadSize, "" );

    if( !seq || ((!array || !block) && total > 0) )
        CV_Error( CV_StsNullPtr, "" );

    memset( seq, 0, header_size );

    seq->header_size = header_size;
    seq->flags = (seq_flags & ~CV_MAGIC_MASK) | CV_SEQ_MAGIC_VAL;
    {
        int elemtype = CV_MAT_TYPE(seq_flags);
        int typesize = CV_ELEM_SIZE(elemtype);

        if( elemtype != CV_SEQ_ELTYPE_GENERIC &&
            typesize != 0 && typesize != elem_size )
            CV_Error( CV_StsBadSize,
            "Element size doesn't match to the size of predefined element type "
            "(try to use 0 for sequence element type)" );
    }
    seq->elem_size = elem_size;
    seq->total = total;
    seq->block_max = seq->ptr = (schar *) array + total * elem_size;

    if( total > 0 )
    {
        seq->first = block;
        block->prev = block->next = block;
        block->start_index = 0;
        block->count = total;
        block->data = (schar *) array;
    }

    result = seq;

    return result;
}


/* The function allocates space for at least one more sequence element.