Regex: WIP support for saving captures
This commit is contained in:
Maxime Coste
parent
ad546e516a
commit
023511deff
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@ -18,6 +18,7 @@ enum Op : char
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AnyChar,
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Jump,
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Split,
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Save,
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LineStart,
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LineEnd,
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WordBoundary,
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@ -83,7 +84,7 @@ struct AstNode
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using AstNodePtr = std::unique_ptr<AstNode>;
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AstNodePtr make_ast_node(Op op, char value = 0,
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AstNodePtr make_ast_node(Op op, char value = -1,
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Quantifier quantifier = {Quantifier::One})
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{
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return AstNodePtr{new AstNode{op, value, quantifier, {}}};
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@ -94,25 +95,29 @@ AstNodePtr make_ast_node(Op op, char value = 0,
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template<typename Iterator>
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struct Parser
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{
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static AstNodePtr parse(Iterator pos, Iterator end)
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AstNodePtr parse(Iterator pos, Iterator end)
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{
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return disjunction(pos, end);
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return disjunction(pos, end, 0);
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}
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private:
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static AstNodePtr disjunction(Iterator& pos, Iterator end)
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AstNodePtr disjunction(Iterator& pos, Iterator end, char capture = -1)
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{
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AstNodePtr node = alternative(pos, end);
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if (pos == end or *pos != '|')
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{
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node->value = capture;
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return node;
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}
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AstNodePtr res = make_ast_node(Op::Alternation);
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res->children.push_back(std::move(node));
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res->children.push_back(disjunction(++pos, end));
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res->value = capture;
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return res;
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}
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static AstNodePtr alternative(Iterator& pos, Iterator end)
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AstNodePtr alternative(Iterator& pos, Iterator end)
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{
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AstNodePtr res = make_ast_node(Op::Sequence);
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while (auto node = term(pos, end))
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@ -120,7 +125,7 @@ private:
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return res;
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}
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static AstNodePtr term(Iterator& pos, Iterator end)
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AstNodePtr term(Iterator& pos, Iterator end)
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{
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if (auto node = assertion(pos, end))
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return node;
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@ -132,7 +137,7 @@ private:
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return nullptr;
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}
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static AstNodePtr assertion(Iterator& pos, Iterator end)
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AstNodePtr assertion(Iterator& pos, Iterator end)
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{
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switch (*pos)
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{
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@ -154,7 +159,7 @@ private:
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return nullptr;
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}
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static AstNodePtr atom(Iterator& pos, Iterator end)
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AstNodePtr atom(Iterator& pos, Iterator end)
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{
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const auto c = *pos;
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switch (c)
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@ -163,7 +168,8 @@ private:
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case '(':
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{
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++pos;
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auto content = disjunction(pos, end);
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auto content = disjunction(pos, end, m_next_capture++);
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if (pos == end or *pos != ')')
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throw runtime_error{"Unclosed parenthesis"};
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++pos;
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@ -177,7 +183,7 @@ private:
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}
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}
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static Quantifier quantifier(Iterator& pos, Iterator end)
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Quantifier quantifier(Iterator& pos, Iterator end)
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{
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auto read_int = [](Iterator& pos, Iterator begin, Iterator end) {
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int res = 0;
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@ -214,6 +220,8 @@ private:
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default: return {Quantifier::One};
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}
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}
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char m_next_capture = 1;
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};
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RegexProgram::Offset compile_node(Vector<char>& program, const AstNodePtr& node);
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@ -234,6 +242,13 @@ RegexProgram::Offset compile_node_inner(Vector<char>& program, const AstNodePtr&
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{
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const auto start_pos = program.size();
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const char capture = (node->op == Op::Alternation or node->op == Op::Sequence) ? node->value : -1;
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if (capture >= 0)
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{
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program.push_back(RegexProgram::Save);
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program.push_back(capture * 2);
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}
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Vector<RegexProgram::Offset> goto_inner_end_offsets;
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switch (node->op)
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{
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@ -288,6 +303,12 @@ RegexProgram::Offset compile_node_inner(Vector<char>& program, const AstNodePtr&
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for (auto& offset : goto_inner_end_offsets)
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get_offset(program, offset) = program.size();
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if (capture >= 0)
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{
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program.push_back(RegexProgram::Save);
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program.push_back(capture * 2 + 1);
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}
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return start_pos;
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}
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@ -338,7 +359,7 @@ Vector<char> compile(const AstNodePtr& node)
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template<typename Iterator>
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Vector<char> compile(Iterator begin, Iterator end)
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{
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return compile(Parser<Iterator>::parse(begin, end));
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return compile(Parser<Iterator>{}.parse(begin, end));
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}
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}
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@ -367,6 +388,9 @@ void dump(ConstArrayView<char> program)
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pos += sizeof(RegexProgram::Offset);
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break;
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}
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case RegexProgram::Save:
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printf("save %d\n", program[pos++]);
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break;
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case RegexProgram::LineStart:
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printf("line start\n");
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break;
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@ -395,72 +419,87 @@ struct ThreadedExecutor
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{
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ThreadedExecutor(ConstArrayView<char> program) : m_program{program} {}
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struct StepResult
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struct Thread
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{
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enum Result { Consumed, Matched, Failed } result;
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const char* next = nullptr;
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const char* inst;
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Vector<const char*> saves = {};
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};
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StepResult step(const char* inst)
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enum class StepResult { Consumed, Matched, Failed };
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StepResult step(size_t thread_index)
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{
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while (true)
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{
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auto& thread = m_threads[thread_index];
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char c = m_pos == m_subject.end() ? 0 : *m_pos;
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const RegexProgram::Op op = (RegexProgram::Op)*inst++;
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const RegexProgram::Op op = (RegexProgram::Op)*thread.inst++;
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switch (op)
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{
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case RegexProgram::Literal:
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if (*inst++ == c)
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return { StepResult::Consumed, inst };
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return { StepResult::Failed };
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if (*thread.inst++ == c)
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return StepResult::Consumed;
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return StepResult::Failed;
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case RegexProgram::AnyChar:
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return { StepResult::Consumed, inst };
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return StepResult::Consumed;
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case RegexProgram::Jump:
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inst = m_program.begin() + *reinterpret_cast<const RegexProgram::Offset*>(inst);
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{
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auto inst = m_program.begin() + *reinterpret_cast<const RegexProgram::Offset*>(thread.inst);
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// if instruction is already going to be executed, drop this thread
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if (std::find(m_threads.begin(), m_threads.end(), inst) != m_threads.end())
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return { StepResult::Failed };
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if (std::find_if(m_threads.begin(), m_threads.end(),
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[inst](const Thread& t) { return t.inst == inst; }) != m_threads.end())
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return StepResult::Failed;
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thread.inst = inst;
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break;
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}
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case RegexProgram::Split:
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{
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add_thread(*reinterpret_cast<const RegexProgram::Offset*>(inst));
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inst += sizeof(RegexProgram::Offset);
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add_thread(*reinterpret_cast<const RegexProgram::Offset*>(thread.inst), thread.saves);
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// thread is invalidated now, as we mutated the m_thread vector
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m_threads[thread_index].inst += sizeof(RegexProgram::Offset);
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break;
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}
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case RegexProgram::Save:
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{
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const char index = *thread.inst++;
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thread.saves[index] = m_pos;
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break;
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}
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case RegexProgram::LineStart:
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if (not is_line_start())
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return { StepResult::Failed };
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return StepResult::Failed;
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break;
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case RegexProgram::LineEnd:
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if (not is_line_end())
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return { StepResult::Failed };
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return StepResult::Failed;
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break;
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case RegexProgram::WordBoundary:
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if (not is_word_boundary())
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return { StepResult::Failed };
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return StepResult::Failed;
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break;
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case RegexProgram::NotWordBoundary:
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if (is_word_boundary())
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return { StepResult::Failed };
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return StepResult::Failed;
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break;
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case RegexProgram::SubjectBegin:
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if (m_pos != m_subject.begin())
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return { StepResult::Failed };
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return StepResult::Failed;
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break;
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case RegexProgram::SubjectEnd:
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if (m_pos != m_subject.end())
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return { StepResult::Failed };
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return StepResult::Failed;
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break;
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case RegexProgram::Match:
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return { StepResult::Matched };
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return StepResult::Matched;
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}
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}
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return { StepResult::Failed };
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return StepResult::Failed;
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}
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bool match(ConstArrayView<char> program, StringView data)
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{
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m_threads = Vector<const char*>{program.begin()};
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m_threads.clear();
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add_thread(0, Vector<const char*>(10, nullptr));
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m_subject = data;
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m_pos = data.begin();
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@ -468,30 +507,39 @@ struct ThreadedExecutor
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{
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for (int i = 0; i < m_threads.size(); ++i)
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{
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auto res = step(m_threads[i]);
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m_threads[i] = res.next;
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if (res.result == StepResult::Matched)
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const auto res = step(i);
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if (res == StepResult::Matched)
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{
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m_captures = std::move(m_threads[i].saves);
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return true;
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}
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m_threads.erase(std::remove(m_threads.begin(), m_threads.end(), nullptr), m_threads.end());
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else if (res == StepResult::Failed)
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m_threads[i].inst = nullptr;
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}
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m_threads.erase(std::remove_if(m_threads.begin(), m_threads.end(),
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[](const Thread& t) { return t.inst == nullptr; }), m_threads.end());
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if (m_threads.empty())
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break;
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return false;
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}
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// Step remaining threads to see if they match without consuming anything else
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for (int i = 0; i < m_threads.size(); ++i)
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{
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if (step(m_threads[i]).result == StepResult::Matched)
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if (step(i) == StepResult::Matched)
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{
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m_captures = std::move(m_threads[i].saves);
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return true;
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}
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}
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return false;
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}
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void add_thread(RegexProgram::Offset pos)
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void add_thread(RegexProgram::Offset pos, Vector<const char*> saves)
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{
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const char* inst = m_program.begin() + pos;
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if (std::find(m_threads.begin(), m_threads.end(), inst) == m_threads.end())
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m_threads.push_back(inst);
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if (std::find_if(m_threads.begin(), m_threads.end(),
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[inst](const Thread& t) { return t.inst == inst; }) == m_threads.end())
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m_threads.push_back({inst, std::move(saves)});
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}
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bool is_line_start() const
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@ -512,7 +560,8 @@ struct ThreadedExecutor
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}
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ConstArrayView<char> m_program;
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Vector<const char*> m_threads;
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Vector<Thread> m_threads;
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Vector<const char*> m_captures;
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StringView m_subject;
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const char* m_pos;
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};
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@ -549,6 +598,7 @@ auto test_regex = UnitTest{[]{
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RegexProgram::dump(program);
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Exec exec{program};
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kak_assert(exec.match(program, "fooquxbarbaz"));
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kak_assert(StringView{exec.m_captures[2], exec.m_captures[3]} == "qux");
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kak_assert(not exec.match(program, "fooquxbarbaze"));
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kak_assert(not exec.match(program, "quxbar"));
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kak_assert(not exec.match(program, "blahblah"));
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@ -562,6 +612,7 @@ auto test_regex = UnitTest{[]{
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RegexProgram::dump(program);
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Exec exec{program};
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kak_assert(exec.match(program, "qux foo baz"));
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kak_assert(StringView{exec.m_captures[2], exec.m_captures[3]} == "foo");
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kak_assert(not exec.match(program, "quxfoobaz"));
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kak_assert(exec.match(program, "bar"));
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kak_assert(not exec.match(program, "foobar"));
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