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Library: allow to consume an iterator while taking the snapshot

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This commit is contained in:
Fischlurch 2017-08-13 01:31:08 +02:00
parent 255958b23b
commit f7402ef89d
2 changed files with 50 additions and 30 deletions
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68
src/lib/iter-adapter-stl.hpp
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@ -421,39 +421,49 @@ namespace iter_stl {
mutable
Sequence buffer_;
size_t pos_;
size_t pos_ = 0;
public:
/** create empty snapshot */
IterSnapshot()
: buffer_()
, pos_(0)
{ }
IterSnapshot() { }
/** take snapshot by discharging a copy
* of the given Lumiera Forward iterator
* @warning depending on the implementation
* backing the source iterator, this
* might or might not yield side-effects.
/** take snapshot by discharging the given Lumiera Forward iterator
* @warning depending on the implementation backing the source iterator,
* this might or might not yield side-effects.
*/
template<class IT>
IterSnapshot (IT& src)
{
for ( ; src; ++src)
buffer_.push_back(*src);
}
/** build snapshot from a copy of the Lumiera Iterator
* @warning depending on the implementation backing the source iterator,
* this might or might not yield side-effects.
*/
template<class IT>
IterSnapshot (IT const& src)
: buffer_()
, pos_(0)
{
for (IT copy(src); copy; ++copy)
for (IT copy{src}; copy; ++copy)
buffer_.push_back(*copy);
}
/** take snapshot by consuming a STL iterator */
template<class IT>
IterSnapshot (IT& pos, IT const& end)
{
for ( ; pos!=end; ++pos)
buffer_.push_back(*pos);
}
/** take snapshot from STL iterator */
template<class IT>
IterSnapshot (IT const& begin, IT const& end)
: buffer_()
, pos_(0)
{
for (IT p(begin); p!=end; ++p)
buffer_.push_back(*p);
for (IT pos{begin}; pos!=end; ++pos)
buffer_.push_back(*pos);
}
IterSnapshot(IterSnapshot &&) = default;
@ -552,9 +562,19 @@ namespace iter_stl {
template<class CON>
inline ContentSnapshot<CON>
snapshot(CON const& con)
{
return ContentSnapshot<CON>(begin(con), end(con));
}
{
return ContentSnapshot<CON>{begin(con), end(con)};
}
/** Take a snapshot of the given LumieraIterator, which is thereby consumed
* @return Lumiera Forward Iterator to yield each Element from this snapshot
*/
template<class IT>
inline ContentSnapshot<IT>
dischargeToSnapshot(IT& ii)
{
return ContentSnapshot<IT>{ii};
}
/** Take a snapshot of the given \c std::initializer_list
* @return Lumiera Forward Iterator to yield each Element from this snapshot
@ -568,10 +588,10 @@ namespace iter_stl {
template<class VAL>
inline iter_stl::IterSnapshot<VAL>
snapshot(std::initializer_list<VAL> const&& ili)
{
using OnceIter = iter_stl::IterSnapshot<VAL>;
return OnceIter(begin(ili), end(ili));
}
{
using OnceIter = iter_stl::IterSnapshot<VAL>;
return OnceIter(begin(ili), end(ili));
}
}} // namespace lib::iter_stl

12
tests/library/iter-adapter-stl-test.cpp
View file

@ -177,9 +177,9 @@ namespace test{
Snapshot capture1 (vec.begin(), vec.end());
Range range_of_all (vec.begin(), vec.end());
Snapshot capture2 (range_of_all);
CHECK (range_of_all); // snapshot doesn't affect given source iterator pos
CHECK (capture2);
Snapshot capture2 = iter::snapshot(range_of_all); // NOTE: when specifically taken this way,
CHECK (range_of_all); // snapshot doesn't affect given source iterator pos
CHECK (capture2); // (but WARNING, the IterSnapshot ctor itself is destructive)
CHECK (vec.begin() == range_of_all.getPos());
CHECK (vec.end() == range_of_all.getEnd());
@ -220,9 +220,9 @@ namespace test{
CHECK (!capture1);
CHECK (!capture2);
CHECK (!capture3);
CHECK (capture1 == capture2);
CHECK (capture3 != capture1); // all exhausted, but the difference in contents remains
CHECK (capture3 != capture2);
CHECK (capture1 == capture2); // all exhausted iterators count as "equal"
CHECK (capture3 == capture1); // this ensures the idiom while(pos != end) works
CHECK (capture3 == capture2);
}
template<class IT>