Re: [Boost-users] multi_array and variants

Subject: Re: [Boost-users] multi_array and variants
From: Krzysztof Czainski (1czajnik_at_[hidden])
Date: 2010-11-08 12:01:39

Hello, Alle

2010/11/8 Alle Meije Wink <a.m.wink_at_[hidden]>

> What I now have is a class bisArray:
> ...
>   template<typename T>
>    class bisArray: public bisObject {
>        typedef boost::variant
>        <   boost::multi_array_ref<T, 1>,
>            boost::multi_array_ref<T, 2>,
>            boost::multi_array_ref<T, 3>,
>            boost::multi_array_ref<T, 4>,
>            boost::multi_array_ref<T, 5>,
>            boost::multi_array_ref<T, 6>,
>            boost::multi_array_ref<T, 7>,
>            boost::multi_array_ref<T, 8>,
>            boost::multi_array_ref<T, 9>
>        > bisArray_t;
>        bisArray_t _bisArray;
> ...
>
> and a class bisImage, which has a bisArray as well as a pointer to the
> data as read from file (1-dimensional structure):
> ...
>
>    template<typename T>
>
>    class bisImage: public bisObject {
>
>    public:
>
>        /** Constructor using existing array data
>              Reformats array as bisImage
>        */
>        bisImage ( T* _data, size_t _dimensions, std::vector<size_t> _sizes
> ):
>                data(_data), dimensions(_dimensions) {
>

This code (or You) comes from java or C#, doesn't it? ;-) In C++ it is
supposed to be this->[...] instead of this.[...]

Second thing: the member storage is initialized with the default constructor
(which in this case does not exist => error ), and then assigned (below).

I suggest a change to:
bisImage([...]) : [...], storage( _data, _dimensions, _size ) { [...]
and remove the assignment from the body of the constructor

Note also: I have read in many places, that you should not use names
beginning with an underscore (_), because they are reserved for
compiler/library implementation. One of those places was Herb Sutter's gotw
series.

>            this.storage=bisArray<T>( _data, _dimensions, _sizes);
>            this.dummy = T();
>        }

...
>
> When I try to initialise an image read from file using
> ...
>   bisImage<unsigned char> newimage=bisImage<unsigned char> ((unsigned
> char *)testimage->data, ndim, dims);
> ...
>
> I get, as the first of many errors, this message
> bisimage.hpp|33|error: no matching function for call to
> ‘canabis::bisArray<unsigned char>::bisArray()’|
>
>
Good lock with Your work on this!

Regards, Kris