home/src/changes.hh

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#ifndef changes_hh_INCLUDED
#define changes_hh_INCLUDED
#include "buffer.hh"
#include "coord.hh"
namespace Kakoune
{
// This tracks position changes for changes that are done
// in a forward way (each change takes place at a position)
// *after* the previous one.
struct ForwardChangesTracker
{
BufferCoord cur_pos; // last change position at current modification
BufferCoord old_pos; // last change position at start
void update(const Buffer::Change& change);
void update(const Buffer& buffer, size_t& timestamp);
BufferCoord get_old_coord(BufferCoord coord) const;
BufferCoord get_new_coord(BufferCoord coord) const;
BufferCoord get_new_coord_tolerant(BufferCoord coord) const;
bool relevant(const Buffer::Change& change, BufferCoord old_coord) const;
};
const Buffer::Change* forward_sorted_until(const Buffer::Change* first, const Buffer::Change* last);
const Buffer::Change* backward_sorted_until(const Buffer::Change* first, const Buffer::Change* last);
template<typename Range, typename AdvanceFunc>
auto update_range(ForwardChangesTracker& changes_tracker, Range& range, AdvanceFunc&& advance_while_relevant)
{
auto& first = get_first(range);
auto& last = get_last(range);
advance_while_relevant(first);
first = changes_tracker.get_new_coord_tolerant(first);
if (last < BufferCoord{0,0})
return;
advance_while_relevant(last);
last = changes_tracker.get_new_coord_tolerant(last);
}
template<typename RangeContainer>
void update_forward(ConstArrayView<Buffer::Change> changes, RangeContainer& ranges)
{
ForwardChangesTracker changes_tracker;
auto advance_while_relevant = [&, it = changes.begin()]
(const BufferCoord& pos) mutable {
while (it != changes.end() and changes_tracker.relevant(*it, pos))
changes_tracker.update(*it++);
};
auto range_it = std::lower_bound(ranges.begin(), ranges.end(), changes.front(),
[](auto& range, const Buffer::Change& change) { return get_last(range) < change.begin; });
for (auto end = ranges.end(); range_it != end; ++range_it)
update_range(changes_tracker, *range_it, advance_while_relevant);
}
template<typename RangeContainer>
void update_backward(ConstArrayView<Buffer::Change> changes, RangeContainer& ranges)
{
ForwardChangesTracker changes_tracker;
auto advance_while_relevant = [&, it = changes.rbegin()]
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(const BufferCoord& pos) mutable {
while (it != changes.rend())
{
const Buffer::Change change{it->type,
changes_tracker.get_new_coord(it->begin),
changes_tracker.get_new_coord(it->end)};
if (not changes_tracker.relevant(change, pos))
break;
changes_tracker.update(change);
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++it;
}
};
for (auto& range : ranges)
update_range(changes_tracker, range, advance_while_relevant);
}
template<typename RangeContainer>
void update_ranges(Buffer& buffer, size_t timestamp, RangeContainer&& ranges)
{
if (timestamp == buffer.timestamp())
return;
auto changes = buffer.changes_since(timestamp);
for (auto change_it = changes.begin(); change_it != changes.end(); )
{
auto forward_end = forward_sorted_until(change_it, changes.end());
auto backward_end = backward_sorted_until(change_it, changes.end());
if (forward_end >= backward_end)
{
update_forward({ change_it, forward_end }, ranges);
change_it = forward_end;
}
else
{
update_backward({ change_it, backward_end }, ranges);
change_it = backward_end;
}
}
}
}
#endif // changes_hh_INCLUDED