Anton Pevtsov wrote:
[...]
Yes it is possible to reverse the expanded substring in known range, but
we check results in other way:
std::size_t match = rw_match (tcase.res, str.data (),
tcase.nres);
Here the rw_match calls rw_expand. These functions know nothing about
the iterators and range bounds and this seems to be a problem.
I'm not sure I understand why that would be a problem. If the driver
replaced the whole tcase structure with one created to match the
expected result when reverse_iterator is used why would rw_match()
or rw_expand() care? (The driver would have to expand the hardcoded
source string and argument in order to figure out the new expected
result).
Suppose the test case is:
string ("abcdef").insert (begin() + 2, first, last);
with the range denoted by the offset into the string and the number
of characters, extent, like so: (offset == 1) and (extent == 3).
The test invokes insert with (first == begin() + offset) and (last
== begin() + offset + extent). The test invokes insert with (first
== begin() + offset) and (last == first + extent) and expects the
result to be the hardcoded "abbcdcdef".
When the driver gets around to exercising reverse_iterators it
changes the offset so that (new_offset == str_size - offset -
extent) and the expected result to "abdbccdef". The test invokes
the function with (first = rbegin() + new_offset) and (last ==
first + extent).
Martin
