[SAGA-RG] saga::file::read and saga::file::write etc.

[Andre Merzky]

Hi Hartmut, 

Quoting [Hartmut Kaiser] (Oct 09 2007):
> 
> Resending because of mailer problems...
> 
> 
> Hi all,
> 
> While trying to implement the latest changes of the spec I have the
> following comments:
> 
> 1. we added the option for a const correct buffer class to the spec,
> shouldn't the same be allowed for the iovec class (i.e. a const correct
> version of the iovec type)

Yep - I'll make sure that it holds for all classes which
derive from buffer.


> 2. I'ld suggest to change the saga::file::read and saga::file::write API
> functions as follows:
> 
>    saga::ssize_t read(saga::mutable_buffer, saga::ssize_t bytes = 0)
>    saga::ssize_t write(saga::const_buffer, saga::ssize_t bytes = 0)
> 
> The rationale behind this is that the buffer already contains a size, which
> by default could be used for the operation (if the 'bytes' parameter is
> zero). In C++ this would allow to simplify the code significantly. i.e.
> 
>   saga::file f(...);
> 
>   char cb[100];
>   f.read(buffer(cb));       // read 100 char's
> 
>   std::vector<double> v(20);
>   f.read(buffer(v, 10));    // read 10 doubles
> 
> Or
> 
>   std::vector<int> vi;
>   // fill vi ...
>   f.write(buffer(vi));      // write all elements of vi
> 
> Etc.

That is already added, although verbosely.  In the detailed
notes to read/write, you should find:

  - if len_in is smaller than 0, or not given, the buffer
    size is used for len_in.  If that is also not available,
    a 'BadParameter' exception is thrown.

I wanted to avoid the default of 'size = 0', because that
would be, although unusual, a valid expression.  -1 would be
invalid.

I'll add the -1 to the prototypes if thats ok with you - not
sure why I left it out in the first place...

And yes, that is how it should like in C++ I guess :-))

> Regards Hartmut

Thanks, Andre.


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