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Refactor parsed regex children iteration to use regular range-for loops

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This commit is contained in:
Maxime Coste 2018-12-19 23:21:47 +11:00
parent 566268d7bc
commit 2afc147b2c
1 changed files with 78 additions and 77 deletions
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123
src/regex_impl.cc
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@ -91,46 +91,52 @@ struct ParsedRegex
namespace
{
template<MatchDirection = MatchDirection::Forward>
struct ForEachChild
template<MatchDirection direction = MatchDirection::Forward>
struct Children
{
template<typename Func>
static bool apply(const ParsedRegex& parsed_regex, ParsedRegex::NodeIndex index, Func&& func)
using Index = ParsedRegex::NodeIndex;
struct Sentinel {};
struct Iterator
{
const auto end = parsed_regex.nodes[index].children_end;
for (auto child = index+1; child != end;
child = parsed_regex.nodes[child].children_end)
static constexpr bool forward = direction == MatchDirection::Forward;
Iterator(ArrayView<const ParsedRegex::Node> nodes, Index index)
: m_nodes{nodes},
m_pos(forward ? index+1 : find_prev(index, nodes[index].children_end)),
m_end(forward ? nodes[index].children_end : index)
{}
Iterator& operator++()
{
if (func(child) == false)
return false;
m_pos = forward ? m_nodes[m_pos].children_end : find_prev(m_end, m_pos);
return *this;
}
return true;
Index operator*() const { return m_pos; }
bool operator!=(Sentinel) const { return m_pos != m_end; }
Index find_prev(Index parent, Index pos) const
{
Index child = parent+1;
if (child == pos)
return parent;
while (m_nodes[child].children_end != pos)
child = m_nodes[child].children_end;
return child;
}
ArrayView<const ParsedRegex::Node> m_nodes;
Index m_pos;
Index m_end;
};
template<>
struct ForEachChild<MatchDirection::Backward>
{
template<typename Func>
static bool apply(const ParsedRegex& parsed_regex, ParsedRegex::NodeIndex index, Func&& func)
{
auto find_last_child = [&](ParsedRegex::NodeIndex begin, ParsedRegex::NodeIndex end) {
while (parsed_regex.nodes[begin].children_end != end)
begin = parsed_regex.nodes[begin].children_end;
return begin;
};
const auto first_child = index+1;
auto end = parsed_regex.nodes[index].children_end;
while (end != first_child)
{
auto child = find_last_child(first_child, end);
if (func(child) == false)
return false;
end = child;
}
return true;
}
Iterator begin() const { return {m_parsed_regex.nodes, m_index}; }
Sentinel end() const { return {}; }
const ParsedRegex& m_parsed_regex;
const Index m_index;
};
}
// Recursive descent parser based on naming used in the ECMAScript
@ -615,7 +621,8 @@ private:
void validate_lookaround(NodeIndex index)
{
using Lookaround = CompiledRegex::Lookaround;
ForEachChild<>::apply(m_parsed_regex, index, [this](NodeIndex child_index) {
for (auto child_index : Children<>{m_parsed_regex, index})
{
auto& child = get_node(child_index);
if (child.op != ParsedRegex::Literal and child.op != ParsedRegex::Class and
child.op != ParsedRegex::CharacterType and child.op != ParsedRegex::AnyChar and
@ -627,8 +634,7 @@ private:
parse_error("Lookaround does not support literals codepoint between 0xF0000 and 0xFFFFD");
if (child.quantifier.type != ParsedRegex::Quantifier::One)
parse_error("Quantifiers cannot be used in lookarounds");
return true;
});
}
}
ParsedRegex m_parsed_regex;
@ -738,22 +744,22 @@ private:
break;
case ParsedRegex::Sequence:
{
ForEachChild<direction>::apply(m_parsed_regex, index, [this](ParsedRegex::NodeIndex child) {
compile_node<direction>(child); return true;
});
for (auto child : Children<direction>{m_parsed_regex, index})
compile_node<direction>(child);
break;
}
case ParsedRegex::Alternation:
{
auto split_pos = m_program.instructions.size();
ForEachChild<>::apply(m_parsed_regex, index, [this, index](ParsedRegex::NodeIndex child) {
for (auto child : Children<>{m_parsed_regex, index})
{
if (child != index+1)
push_inst(CompiledRegex::Split_PrioritizeParent);
return true;
});
}
ForEachChild<>::apply(m_parsed_regex, index,
[&, end = node.children_end](ParsedRegex::NodeIndex child) {
const auto end = node.children_end;
for (auto child : Children<>{m_parsed_regex, index})
{
auto node = compile_node<direction>(child);
if (child != index+1)
m_program.instructions[split_pos++].param = node;
@ -762,8 +768,7 @@ private:
auto jump = push_inst(CompiledRegex::Jump);
goto_inner_end_offsets.push_back(jump);
}
return true;
});
}
break;
}
case ParsedRegex::LookAhead:
@ -886,7 +891,8 @@ private:
using Lookaround = CompiledRegex::Lookaround;
const uint32_t res = m_program.lookarounds.size();
auto write_matcher = [this, ignore_case](ParsedRegex::NodeIndex child) {
for (auto child : Children<direction>{m_parsed_regex, index})
{
auto& character = get_node(child);
if (character.op == ParsedRegex::Literal)
m_program.lookarounds.push_back(
@ -901,11 +907,7 @@ private:
m_program.lookarounds.push_back(static_cast<Lookaround>(to_underlying(Lookaround::CharacterType) | character.value));
else
kak_assert(false);
return true;
};
ForEachChild<direction>::apply(m_parsed_regex, index, write_matcher);
}
m_program.lookarounds.push_back(Lookaround::EndOfLookaround);
return res;
}
@ -983,22 +985,21 @@ private:
}
case ParsedRegex::Sequence:
{
bool did_not_consume = false;
auto does_not_consume = [&, this](auto child) {
return this->compute_start_desc<direction>(child, start_desc);
};
did_not_consume = ForEachChild<direction>::apply(m_parsed_regex, index, does_not_consume);
return did_not_consume or node.quantifier.allows_none();
for (auto child : Children<direction>{m_parsed_regex, index})
{
if (not compute_start_desc<direction>(child, start_desc))
return node.quantifier.allows_none();
}
return true;
}
case ParsedRegex::Alternation:
{
bool all_consumed = not node.quantifier.allows_none();
ForEachChild<>::apply(m_parsed_regex, index, [&](ParsedRegex::NodeIndex child) {
for (auto child : Children<>{m_parsed_regex, index})
{
if (compute_start_desc<direction>(child, start_desc))
all_consumed = false;
return true;
});
}
return not all_consumed;
}
case ParsedRegex::LineStart: