Regex: Add support for curly braces count expressions
This commit is contained in:
Maxime Coste
parent
d04c60b911
commit
46a113e10a
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@ -31,12 +31,32 @@ using Offset = size_t;
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namespace RegexCompiler
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{
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enum class Quantifier
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struct Quantifier
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{
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enum Type
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{
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One,
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Optional,
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RepeatZeroOrMore,
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RepeatOneOrMore
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RepeatOneOrMore,
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RepeatMinMax,
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};
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Type type = One;
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int min = -1, max = -1;
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bool allows_none() const
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{
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return type == Quantifier::Optional or
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type == Quantifier::RepeatZeroOrMore or
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(type == Quantifier::RepeatMinMax and min <= 0);
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}
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bool allows_infinite_repeat() const
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{
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return type == Quantifier::RepeatZeroOrMore or
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type == Quantifier::RepeatOneOrMore or
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(type == Quantifier::RepeatMinMax and max == -1);
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};
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};
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enum class Op
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@ -64,7 +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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Quantifier quantifier = Quantifier::One)
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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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}
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@ -157,49 +177,62 @@ private:
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static 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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for (; pos != end; ++pos)
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{
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const auto c = *pos;
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if (c < '0' or c > '9')
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return pos == begin ? -1 : res;
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res = res * 10 + c - '0';
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}
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return res;
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};
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switch (*pos)
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{
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case '*': ++pos; return Quantifier::RepeatZeroOrMore;
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case '+': ++pos; return Quantifier::RepeatOneOrMore;
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case '?': ++pos; return Quantifier::Optional;
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default: return Quantifier::One;
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case '*': ++pos; return {Quantifier::RepeatZeroOrMore};
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case '+': ++pos; return {Quantifier::RepeatOneOrMore};
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case '?': ++pos; return {Quantifier::Optional};
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case '{':
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{
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auto it = pos+1;
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int min = read_int(it, it, end);
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int max = -1;
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if (*it == ',')
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{
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++it;
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max = read_int(it, it, end);
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}
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if (*it++ != '}')
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throw runtime_error{"expected closing bracket"};
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pos = it;
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return {Quantifier::RepeatMinMax, min, max};
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}
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default: return {Quantifier::One};
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}
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}
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};
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RegexProgram::Offset compile_node(Vector<char>& program, const AstNodePtr& node)
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RegexProgram::Offset compile_node(Vector<char>& program, const AstNodePtr& node);
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RegexProgram::Offset alloc_offset(Vector<char>& instructions)
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{
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RegexProgram::Offset pos = program.size();
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auto allow_none = [](Quantifier quantifier) {
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return quantifier == Quantifier::Optional or
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quantifier == Quantifier::RepeatZeroOrMore;
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};
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auto is_repeat = [](Quantifier quantifier) {
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return quantifier == Quantifier::RepeatZeroOrMore or
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quantifier == Quantifier::RepeatOneOrMore;
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};
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auto alloc_offset = [](Vector<char>& instructions) {
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auto pos = instructions.size();
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instructions.resize(instructions.size() + sizeof(RegexProgram::Offset));
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return pos;
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};
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}
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auto get_offset = [](Vector<char>& instructions, RegexProgram::Offset base) -> RegexProgram::Offset& {
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RegexProgram::Offset& get_offset(Vector<char>& instructions, RegexProgram::Offset base)
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{
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return *reinterpret_cast<RegexProgram::Offset*>(&instructions[base]);
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};
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}
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RegexProgram::Offset optional_offset = -1;
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if (allow_none(node->quantifier))
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{
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program.push_back(RegexProgram::Split);
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optional_offset = alloc_offset(program);
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}
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RegexProgram::Offset compile_node_inner(Vector<char>& program, const AstNodePtr& node)
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{
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const auto start_pos = program.size();
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Vector<RegexProgram::Offset> goto_end_offsets;
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auto content_pos = program.size();
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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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case Op::Literal:
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@ -223,7 +256,7 @@ RegexProgram::Offset compile_node(Vector<char>& program, const AstNodePtr& node)
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compile_node(program, children[0]);
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program.push_back(RegexProgram::Jump);
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goto_end_offsets.push_back(alloc_offset(program));
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goto_inner_end_offsets.push_back(alloc_offset(program));
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auto right_pos = compile_node(program, children[1]);
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get_offset(program, offset) = right_pos;
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@ -250,17 +283,44 @@ RegexProgram::Offset compile_node(Vector<char>& program, const AstNodePtr& node)
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break;
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}
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for (auto& offset : goto_end_offsets)
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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 (is_repeat(node->quantifier))
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return start_pos;
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}
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RegexProgram::Offset compile_node(Vector<char>& program, const AstNodePtr& node)
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{
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RegexProgram::Offset pos = program.size();
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Vector<RegexProgram::Offset> goto_end_offsets;
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if (node->quantifier.allows_none())
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{
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program.push_back(RegexProgram::Split);
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get_offset(program, alloc_offset(program)) = content_pos;
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goto_end_offsets.push_back(alloc_offset(program));
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}
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if (optional_offset != -1)
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get_offset(program, optional_offset) = program.size();
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auto inner_pos = compile_node_inner(program, node);
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// Write the node multiple times when we have a min count quantifier
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for (int i = 1; i < node->quantifier.min; ++i)
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inner_pos = compile_node_inner(program, node);
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if (node->quantifier.allows_infinite_repeat())
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{
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program.push_back(RegexProgram::Split);
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get_offset(program, alloc_offset(program)) = inner_pos;
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}
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// Write the node as an optional match for the min -> max counts
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else for (int i = std::max(1, node->quantifier.min); // STILL UGLY !
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i < node->quantifier.max; ++i)
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{
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program.push_back(RegexProgram::Split);
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goto_end_offsets.push_back(alloc_offset(program));
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compile_node_inner(program, node);
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}
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for (auto offset : goto_end_offsets)
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get_offset(program, offset) = program.size();
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return pos;
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}
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@ -513,6 +573,38 @@ auto test_regex = UnitTest{[]{
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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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}
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{
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StringView re = R"(\`a{3,5}b\')";
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auto program = RegexCompiler::compile(re.begin(), re.end());
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RegexProgram::dump(program);
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Exec exec{program};
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kak_assert(not exec.match(program, "aab"));
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kak_assert(exec.match(program, "aaab"));
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kak_assert(not exec.match(program, "aaaaaab"));
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kak_assert(exec.match(program, "aaaaab"));
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}
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{
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StringView re = R"(\`a{3,}b\')";
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auto program = RegexCompiler::compile(re.begin(), re.end());
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RegexProgram::dump(program);
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Exec exec{program};
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kak_assert(not exec.match(program, "aab"));
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kak_assert(exec.match(program, "aaab"));
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kak_assert(exec.match(program, "aaaaab"));
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}
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{
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StringView re = R"(\`a{,3}b\')";
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auto program = RegexCompiler::compile(re.begin(), re.end());
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RegexProgram::dump(program);
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Exec exec{program};
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kak_assert(exec.match(program, "b"));
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kak_assert(exec.match(program, "ab"));
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kak_assert(exec.match(program, "aaab"));
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kak_assert(not exec.match(program, "aaaab"));
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}
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}};
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}
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