Testsuite Iterators

[Chris Jefferson]

The recent patch to search_n I submitted has a specialisation for random 
access iterators, and therefore the test suite should test both the 
non-random access and the random access versions for correctness.

After the advise of Martin Sebor, I decided to write a set of iterator 
adaptors which would, given an array of some type T, provide iterators 
of various types over this array.

I now have various different methods of doing this, and I thought I 
would ask which people considered the most sensible to try to submit for 
inclusion for use in the testsuite.

a) Just use vector<> when you want a random access iterator, list<> when 
you want a bidirection one, etc.

b) Make a set of iterators, each of which has a single constructor 
taking a single pointer.

c) Make a set of iterators, each of which has a constructor which takes 
3 elements (2 in the case of forward/input/output iterators), denoting 
the current iterator position and the first and last positions the 
iterator can take

d) Make "minimal containers" which take 2 pointers, one for the start 
and one for the end of the range. Give these begin(),end() and possibly 
a new function getIt(int i) which returns an iterator pointing to ith 
element.

e) Make full blown proper containers, which once again take 2 pointers 
representing the beginning and the end of the range which the iterators 
should range over.

Personally, I am tempted by c) or d). d) looks slightly nicer but 
doesn't really save that much typing. I would be interested to know of 
any other opinions.

I would hope after polishing and submitting these iterator wrappers, 
that they would then be used in the testsuite as firstly they would be 
as "tight" as possible with regards the standard, stopping at any 
undefined behaviour, and secondly they would remove dependance on 
vector,list, etc. which may have bugs or pecularities of their own.

Chris