Function cvGetReal1D

deps/opencv/modules/core/src/array.cpp:2021–2056

Returns specifed element of n-D array given linear index

// Returns specifed element of n-D array given linear index
CV_IMPL  double
cvGetReal1D( const CvArr* arr, int idx )
{
    double value = 0;
    int type = 0;
    uchar* ptr;

    if( CV_IS_MAT( arr ) && CV_IS_MAT_CONT( ((CvMat*)arr)->type ))
    {
        CvMat* mat = (CvMat*)arr;

        type = CV_MAT_TYPE(mat->type);
        int pix_size = CV_ELEM_SIZE(type);

        // the first part is mul-free sufficient check
        // that the index is within the matrix
        if( (unsigned)idx >= (unsigned)(mat->rows + mat->cols - 1) &&
            (unsigned)idx >= (unsigned)(mat->rows*mat->cols))
            CV_Error( CV_StsOutOfRange, "index is out of range" );

        ptr = mat->data.ptr + (size_t)idx*pix_size;
    }
    else if( !CV_IS_SPARSE_MAT( arr ) || ((CvSparseMat*)arr)->dims > 1 )
        ptr = cvPtr1D( arr, idx, &type );
    else
        ptr = icvGetNodePtr( (CvSparseMat*)arr, &idx, &type, 0, 0 );

    if( ptr )
    {
        if( CV_MAT_CN( type ) > 1 )
            CV_Error( CV_BadNumChannels, "cvGetReal* support only single-channel arrays" );

        value = icvGetReal( ptr, type );
    }
    return value;
}


// Returns specifed element of 2D array