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Regex: Add support for curly braces count expressions

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This commit is contained in:
Maxime Coste 2017-09-18 18:22:11 +09:00
parent d04c60b911
commit 46a113e10a
1 changed files with 137 additions and 45 deletions
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178
src/regex_impl.cc
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@ -31,12 +31,32 @@ using Offset = size_t;
namespace RegexCompiler
{
enum class Quantifier
struct Quantifier
{
enum Type
{
One,
Optional,
RepeatZeroOrMore,
RepeatOneOrMore
RepeatOneOrMore,
RepeatMinMax,
};
Type type = One;
int min = -1, max = -1;
bool allows_none() const
{
return type == Quantifier::Optional or
type == Quantifier::RepeatZeroOrMore or
(type == Quantifier::RepeatMinMax and min <= 0);
}
bool allows_infinite_repeat() const
{
return type == Quantifier::RepeatZeroOrMore or
type == Quantifier::RepeatOneOrMore or
(type == Quantifier::RepeatMinMax and max == -1);
};
};
enum class Op
@ -64,7 +84,7 @@ struct AstNode
using AstNodePtr = std::unique_ptr<AstNode>;
AstNodePtr make_ast_node(Op op, char value = 0,
Quantifier quantifier = Quantifier::One)
Quantifier quantifier = {Quantifier::One})
{
return AstNodePtr{new AstNode{op, value, quantifier, {}}};
}
@ -157,49 +177,62 @@ private:
static Quantifier quantifier(Iterator& pos, Iterator end)
{
auto read_int = [](Iterator& pos, Iterator begin, Iterator end) {
int res = 0;
for (; pos != end; ++pos)
{
const auto c = *pos;
if (c < '0' or c > '9')
return pos == begin ? -1 : res;
res = res * 10 + c - '0';
}
return res;
};
switch (*pos)
{
case '*': ++pos; return Quantifier::RepeatZeroOrMore;
case '+': ++pos; return Quantifier::RepeatOneOrMore;
case '?': ++pos; return Quantifier::Optional;
default: return Quantifier::One;
}
}
};
RegexProgram::Offset compile_node(Vector<char>& program, const AstNodePtr& node)
case '*': ++pos; return {Quantifier::RepeatZeroOrMore};
case '+': ++pos; return {Quantifier::RepeatOneOrMore};
case '?': ++pos; return {Quantifier::Optional};
case '{':
{
RegexProgram::Offset pos = program.size();
auto allow_none = [](Quantifier quantifier) {
return quantifier == Quantifier::Optional or
quantifier == Quantifier::RepeatZeroOrMore;
auto it = pos+1;
int min = read_int(it, it, end);
int max = -1;
if (*it == ',')
{
++it;
max = read_int(it, it, end);
}
if (*it++ != '}')
throw runtime_error{"expected closing bracket"};
pos = it;
return {Quantifier::RepeatMinMax, min, max};
}
default: return {Quantifier::One};
}
}
};
auto is_repeat = [](Quantifier quantifier) {
return quantifier == Quantifier::RepeatZeroOrMore or
quantifier == Quantifier::RepeatOneOrMore;
};
RegexProgram::Offset compile_node(Vector<char>& program, const AstNodePtr& node);
auto alloc_offset = [](Vector<char>& instructions) {
RegexProgram::Offset alloc_offset(Vector<char>& instructions)
{
auto pos = instructions.size();
instructions.resize(instructions.size() + sizeof(RegexProgram::Offset));
return pos;
};
auto get_offset = [](Vector<char>& instructions, RegexProgram::Offset base) -> RegexProgram::Offset& {
return *reinterpret_cast<RegexProgram::Offset*>(&instructions[base]);
};
RegexProgram::Offset optional_offset = -1;
if (allow_none(node->quantifier))
{
program.push_back(RegexProgram::Split);
optional_offset = alloc_offset(program);
}
Vector<RegexProgram::Offset> goto_end_offsets;
auto content_pos = program.size();
RegexProgram::Offset& get_offset(Vector<char>& instructions, RegexProgram::Offset base)
{
return *reinterpret_cast<RegexProgram::Offset*>(&instructions[base]);
}
RegexProgram::Offset compile_node_inner(Vector<char>& program, const AstNodePtr& node)
{
const auto start_pos = program.size();
Vector<RegexProgram::Offset> goto_inner_end_offsets;
switch (node->op)
{
case Op::Literal:
@ -223,7 +256,7 @@ RegexProgram::Offset compile_node(Vector<char>& program, const AstNodePtr& node)
compile_node(program, children[0]);
program.push_back(RegexProgram::Jump);
goto_end_offsets.push_back(alloc_offset(program));
goto_inner_end_offsets.push_back(alloc_offset(program));
auto right_pos = compile_node(program, children[1]);
get_offset(program, offset) = right_pos;
@ -250,17 +283,44 @@ RegexProgram::Offset compile_node(Vector<char>& program, const AstNodePtr& node)
break;
}
for (auto& offset : goto_end_offsets)
for (auto& offset : goto_inner_end_offsets)
get_offset(program, offset) = program.size();
if (is_repeat(node->quantifier))
{
program.push_back(RegexProgram::Split);
get_offset(program, alloc_offset(program)) = content_pos;
return start_pos;
}
if (optional_offset != -1)
get_offset(program, optional_offset) = program.size();
RegexProgram::Offset compile_node(Vector<char>& program, const AstNodePtr& node)
{
RegexProgram::Offset pos = program.size();
Vector<RegexProgram::Offset> goto_end_offsets;
if (node->quantifier.allows_none())
{
program.push_back(RegexProgram::Split);
goto_end_offsets.push_back(alloc_offset(program));
}
auto inner_pos = compile_node_inner(program, node);
// Write the node multiple times when we have a min count quantifier
for (int i = 1; i < node->quantifier.min; ++i)
inner_pos = compile_node_inner(program, node);
if (node->quantifier.allows_infinite_repeat())
{
program.push_back(RegexProgram::Split);
get_offset(program, alloc_offset(program)) = inner_pos;
}
// Write the node as an optional match for the min -> max counts
else for (int i = std::max(1, node->quantifier.min); // STILL UGLY !
i < node->quantifier.max; ++i)
{
program.push_back(RegexProgram::Split);
goto_end_offsets.push_back(alloc_offset(program));
compile_node_inner(program, node);
}
for (auto offset : goto_end_offsets)
get_offset(program, offset) = program.size();
return pos;
}
@ -513,6 +573,38 @@ auto test_regex = UnitTest{[]{
kak_assert(exec.match(program, "bar"));
kak_assert(not exec.match(program, "foobar"));
}
{
StringView re = R"(\`a{3,5}b\')";
auto program = RegexCompiler::compile(re.begin(), re.end());
RegexProgram::dump(program);
Exec exec{program};
kak_assert(not exec.match(program, "aab"));
kak_assert(exec.match(program, "aaab"));
kak_assert(not exec.match(program, "aaaaaab"));
kak_assert(exec.match(program, "aaaaab"));
}
{
StringView re = R"(\`a{3,}b\')";
auto program = RegexCompiler::compile(re.begin(), re.end());
RegexProgram::dump(program);
Exec exec{program};
kak_assert(not exec.match(program, "aab"));
kak_assert(exec.match(program, "aaab"));
kak_assert(exec.match(program, "aaaaab"));
}
{
StringView re = R"(\`a{,3}b\')";
auto program = RegexCompiler::compile(re.begin(), re.end());
RegexProgram::dump(program);
Exec exec{program};
kak_assert(exec.match(program, "b"));
kak_assert(exec.match(program, "ab"));
kak_assert(exec.match(program, "aaab"));
kak_assert(not exec.match(program, "aaaab"));
}
}};
}