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Regex: refactor handling of Saves slightly, do not create them until really needed

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This commit is contained in:
Maxime Coste 2017-10-20 16:55:38 +08:00
parent d9b4076e3c
commit e9e9a08e7b
1 changed files with 18 additions and 12 deletions
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30
src/regex_impl.hh
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@ -152,17 +152,12 @@ public:
((flags & RegexExecFlags::NotEndOfLine) ? RegexExecFlags::NotBeginOfLine : RegexExecFlags::None) |
((flags & RegexExecFlags::NotBeginOfLine) ? RegexExecFlags::NotEndOfLine : RegexExecFlags::None);
const bool no_saves = (flags & RegexExecFlags::NoSaves);
const bool search = (flags & RegexExecFlags::Search);
Utf8It start{m_begin};
if (search)
to_next_start(start, m_end, m_program.start_chars.get());
ExecState state;
return exec_program(start, search ? 0 : CompiledRegex::search_prefix_size,
no_saves ? nullptr : new_saves<false>(nullptr), state);
return exec_program(start, Thread{search ? (uint16_t)0 : CompiledRegex::search_prefix_size, nullptr});
}
ArrayView<const Iterator> captures() const
@ -240,6 +235,7 @@ private:
// Steps a thread until it consumes the current character, matches or fail
StepResult step(Utf8It& pos, Thread& thread, ExecState& state)
{
const bool no_saves = (m_flags & RegexExecFlags::NoSaves);
while (true)
{
auto& inst = m_program.instructions[thread.inst++];
@ -279,9 +275,11 @@ private:
}
case CompiledRegex::Save:
{
if (thread.saves == nullptr)
if (no_saves)
break;
if (thread.saves->refcount > 1)
if (not thread.saves)
thread.saves = new_saves<false>(nullptr);
else if (thread.saves->refcount > 1)
{
--thread.saves->refcount;
thread.saves = new_saves<true>(thread.saves->pos);
@ -354,10 +352,10 @@ private:
return StepResult::Failed;
}
bool exec_program(Utf8It pos, uint16_t first_inst, Saves* initial_saves, ExecState& state)
bool exec_program(Utf8It pos, Thread init_thread)
{
state.current_threads.push_back({first_inst, initial_saves});
state.next_threads.clear();
ExecState state;
state.current_threads.push_back(init_thread);
bool found_match = false;
while (true) // Iterate on all codepoints and once at the end
@ -388,7 +386,11 @@ private:
release_saves(m_captures);
m_captures = thread.saves;
found_match = true;
state.current_threads.clear(); // remove this and lower priority threads
// remove this and lower priority threads
for (auto& t : state.current_threads)
release_saves(t.saves);
state.current_threads.clear();
break;
case StepResult::Failed:
release_saves(thread.saves);
@ -413,7 +415,11 @@ private:
if (pos == m_end or state.next_threads.empty() or
(found_match and (m_flags & RegexExecFlags::AnyMatch)))
{
for (auto& t : state.next_threads)
release_saves(t.saves);
return found_match;
}
std::swap(state.current_threads, state.next_threads);
std::reverse(state.current_threads.begin(), state.current_threads.end());