556 lines
19 KiB
C++
556 lines
19 KiB
C++
#ifndef regex_impl_hh_INCLUDED
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#define regex_impl_hh_INCLUDED
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#include "exception.hh"
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#include "flags.hh"
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#include "ref_ptr.hh"
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#include "unicode.hh"
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#include "utf8.hh"
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#include "utf8_iterator.hh"
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#include "vector.hh"
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namespace Kakoune
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{
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struct regex_error : runtime_error
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{
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using runtime_error::runtime_error;
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};
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enum class MatchDirection
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{
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Forward,
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Backward
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};
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struct CompiledRegex : RefCountable, UseMemoryDomain<MemoryDomain::Regex>
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{
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enum Op : char
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{
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Match,
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FindNextStart,
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Literal,
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Literal_IgnoreCase,
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AnyChar,
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Matcher,
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Jump,
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Split_PrioritizeParent,
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Split_PrioritizeChild,
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Save,
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LineStart,
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LineEnd,
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WordBoundary,
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NotWordBoundary,
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SubjectBegin,
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SubjectEnd,
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LookAhead,
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NegativeLookAhead,
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LookBehind,
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NegativeLookBehind,
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LookAhead_IgnoreCase,
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NegativeLookAhead_IgnoreCase,
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LookBehind_IgnoreCase,
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NegativeLookBehind_IgnoreCase,
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};
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struct Instruction
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{
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Op op;
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// Those mutables are used during execution
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mutable bool scheduled;
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mutable uint16_t last_step;
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uint32_t param;
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};
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static_assert(sizeof(Instruction) == 8, "");
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static constexpr uint16_t search_prefix_size = 3;
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explicit operator bool() const { return not instructions.empty(); }
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Vector<Instruction, MemoryDomain::Regex> instructions;
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Vector<std::function<bool (Codepoint)>, MemoryDomain::Regex> matchers;
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Vector<Codepoint, MemoryDomain::Regex> lookarounds;
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MatchDirection direction;
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size_t save_count;
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struct StartChars
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{
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static constexpr size_t count = 256;
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static constexpr Codepoint other = 256;
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bool map[count+1];
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};
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std::unique_ptr<StartChars> start_chars;
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};
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enum class RegexCompileFlags
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{
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None = 0,
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NoSubs = 1 << 0,
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Optimize = 1 << 1
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};
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constexpr bool with_bit_ops(Meta::Type<RegexCompileFlags>) { return true; }
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CompiledRegex compile_regex(StringView re, RegexCompileFlags flags, MatchDirection direction = MatchDirection::Forward);
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enum class RegexExecFlags
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{
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None = 0,
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Search = 1 << 0,
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NotBeginOfLine = 1 << 1,
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NotEndOfLine = 1 << 2,
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NotBeginOfWord = 1 << 3,
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NotEndOfWord = 1 << 4,
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NotBeginOfSubject = 1 << 5,
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NotInitialNull = 1 << 6,
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AnyMatch = 1 << 7,
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NoSaves = 1 << 8,
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PrevAvailable = 1 << 9,
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};
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constexpr bool with_bit_ops(Meta::Type<RegexExecFlags>) { return true; }
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template<typename Iterator, MatchDirection direction>
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class ThreadedRegexVM
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{
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public:
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ThreadedRegexVM(const CompiledRegex& program)
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: m_program{program}
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{
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kak_assert(m_program and direction == m_program.direction);
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}
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ThreadedRegexVM(const ThreadedRegexVM&) = delete;
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ThreadedRegexVM& operator=(const ThreadedRegexVM&) = delete;
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~ThreadedRegexVM()
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{
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for (auto* saves : m_saves)
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{
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for (size_t i = m_program.save_count-1; i > 0; --i)
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saves->pos[i].~Iterator();
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saves->~Saves();
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operator delete(saves);
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}
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}
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bool exec(Iterator begin, Iterator end, RegexExecFlags flags)
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{
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if (flags & RegexExecFlags::NotInitialNull and begin == end)
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return false;
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constexpr bool forward = direction == MatchDirection::Forward;
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const bool prev_avail = flags & RegexExecFlags::PrevAvailable;
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m_begin = Utf8It{utf8::iterator<Iterator>{forward ? begin : end,
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prev_avail ? begin-1 : begin, end}};
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m_end = Utf8It{utf8::iterator<Iterator>{forward ? end : begin,
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prev_avail ? begin-1 : begin, end}};
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if (forward)
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m_flags = flags;
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else // Flip line begin/end flags as we flipped the instructions on compilation.
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m_flags = (RegexExecFlags)(flags & ~(RegexExecFlags::NotEndOfLine | RegexExecFlags::NotBeginOfLine)) |
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((flags & RegexExecFlags::NotEndOfLine) ? RegexExecFlags::NotBeginOfLine : RegexExecFlags::None) |
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((flags & RegexExecFlags::NotBeginOfLine) ? RegexExecFlags::NotEndOfLine : RegexExecFlags::None);
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const bool search = (flags & RegexExecFlags::Search);
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Utf8It start{m_begin};
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if (search)
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to_next_start(start, m_end, m_program.start_chars.get());
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return exec_program(start, Thread{&m_program.instructions[search ? 0 : CompiledRegex::search_prefix_size], nullptr});
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}
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ArrayView<const Iterator> captures() const
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{
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if (m_captures)
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return { m_captures->pos, m_program.save_count };
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return {};
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}
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private:
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struct Saves
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{
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union // ref count when in use, next_free when in free list
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{
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int refcount;
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Saves* next_free;
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};
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Iterator pos[1];
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};
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template<bool copy>
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Saves* new_saves(Iterator* pos)
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{
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kak_assert(not copy or pos != nullptr);
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const auto count = m_program.save_count;
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if (m_first_free != nullptr)
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{
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Saves* res = m_first_free;
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m_first_free = res->next_free;
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res->refcount = 1;
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if (copy)
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std::copy(pos, pos + count, res->pos);
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else
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std::fill(res->pos, res->pos + count, Iterator{});
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return res;
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}
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void* ptr = operator new (sizeof(Saves) + (count-1) * sizeof(Iterator));
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Saves* saves = new (ptr) Saves{{1}, {copy ? pos[0] : Iterator{}}};
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for (size_t i = 1; i < count; ++i)
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new (&saves->pos[i]) Iterator{copy ? pos[i] : Iterator{}};
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m_saves.push_back(saves);
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return saves;
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}
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void release_saves(Saves* saves)
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{
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if (saves and --saves->refcount == 0)
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{
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saves->next_free = m_first_free;
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m_first_free = saves;
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}
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};
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struct Thread
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{
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const CompiledRegex::Instruction* inst;
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Saves* saves;
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};
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using Utf8It = std::conditional_t<direction == MatchDirection::Forward,
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utf8::iterator<Iterator>,
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std::reverse_iterator<utf8::iterator<Iterator>>>;
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struct ExecState
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{
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Vector<Thread, MemoryDomain::Regex> current_threads;
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Vector<Thread, MemoryDomain::Regex> next_threads;
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uint16_t step = -1;
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};
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enum class StepResult { Consumed, Matched, Failed, FindNextStart };
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// Steps a thread until it consumes the current character, matches or fail
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StepResult step(Utf8It& pos, Thread& thread, ExecState& state)
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{
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const bool no_saves = (m_flags & RegexExecFlags::NoSaves);
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auto* instructions = m_program.instructions.data();
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while (true)
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{
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auto& inst = *thread.inst++;
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if (inst.last_step == state.step)
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return StepResult::Failed;
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inst.last_step = state.step;
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switch (inst.op)
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{
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case CompiledRegex::Literal:
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if (pos != m_end and inst.param == *pos)
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return StepResult::Consumed;
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return StepResult::Failed;
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case CompiledRegex::Literal_IgnoreCase:
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if (pos != m_end and inst.param == to_lower(*pos))
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return StepResult::Consumed;
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return StepResult::Failed;
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case CompiledRegex::AnyChar:
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return StepResult::Consumed;
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case CompiledRegex::Jump:
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thread.inst = instructions + inst.param;
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break;
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case CompiledRegex::Split_PrioritizeParent:
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{
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if (thread.saves)
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++thread.saves->refcount;
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state.current_threads.push_back({instructions + inst.param, thread.saves});
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break;
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}
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case CompiledRegex::Split_PrioritizeChild:
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{
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if (thread.saves)
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++thread.saves->refcount;
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state.current_threads.push_back({thread.inst, thread.saves});
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thread.inst = instructions + inst.param;
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break;
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}
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case CompiledRegex::Save:
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{
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if (no_saves)
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break;
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if (not thread.saves)
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thread.saves = new_saves<false>(nullptr);
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else if (thread.saves->refcount > 1)
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{
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--thread.saves->refcount;
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thread.saves = new_saves<true>(thread.saves->pos);
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}
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thread.saves->pos[inst.param] = get_base(pos);
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break;
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}
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case CompiledRegex::Matcher:
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if (pos == m_end)
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return StepResult::Failed;
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return m_program.matchers[inst.param](*pos) ?
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StepResult::Consumed : StepResult::Failed;
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case CompiledRegex::LineStart:
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if (not is_line_start(pos))
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return StepResult::Failed;
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break;
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case CompiledRegex::LineEnd:
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if (not is_line_end(pos))
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return StepResult::Failed;
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break;
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case CompiledRegex::WordBoundary:
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if (not is_word_boundary(pos))
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return StepResult::Failed;
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break;
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case CompiledRegex::NotWordBoundary:
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if (is_word_boundary(pos))
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return StepResult::Failed;
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break;
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case CompiledRegex::SubjectBegin:
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if (pos != m_begin or (m_flags & RegexExecFlags::NotBeginOfSubject))
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return StepResult::Failed;
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break;
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case CompiledRegex::SubjectEnd:
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if (pos != m_end)
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return StepResult::Failed;
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break;
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case CompiledRegex::LookAhead:
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case CompiledRegex::NegativeLookAhead:
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if (lookaround<MatchDirection::Forward, false>(inst.param, pos) !=
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(inst.op == CompiledRegex::LookAhead))
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return StepResult::Failed;
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break;
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case CompiledRegex::LookAhead_IgnoreCase:
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case CompiledRegex::NegativeLookAhead_IgnoreCase:
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if (lookaround<MatchDirection::Forward, true>(inst.param, pos) !=
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(inst.op == CompiledRegex::LookAhead_IgnoreCase))
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return StepResult::Failed;
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break;
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case CompiledRegex::LookBehind:
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case CompiledRegex::NegativeLookBehind:
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if (lookaround<MatchDirection::Backward, false>(inst.param, pos) !=
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(inst.op == CompiledRegex::LookBehind))
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return StepResult::Failed;
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break;
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case CompiledRegex::LookBehind_IgnoreCase:
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case CompiledRegex::NegativeLookBehind_IgnoreCase:
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if (lookaround<MatchDirection::Backward, true>(inst.param, pos) !=
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(inst.op == CompiledRegex::LookBehind_IgnoreCase))
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return StepResult::Failed;
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break;
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case CompiledRegex::FindNextStart:
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kak_assert(state.current_threads.empty()); // search thread should by construction be the lower priority one
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if (state.next_threads.empty())
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return StepResult::FindNextStart;
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return StepResult::Consumed;
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case CompiledRegex::Match:
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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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}
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bool exec_program(Utf8It pos, Thread init_thread)
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{
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ExecState state;
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state.current_threads.push_back(init_thread);
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bool found_match = false;
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while (true) // Iterate on all codepoints and once at the end
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{
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if (++state.step == 0)
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{
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// We wrapped, avoid potential collision on inst.last_step by resetting them
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for (auto& inst : m_program.instructions)
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inst.last_step = 0;
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state.step = 1; // step 0 is never valid
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}
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bool find_next_start = false;
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while (not state.current_threads.empty())
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{
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auto thread = state.current_threads.back();
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state.current_threads.pop_back();
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switch (step(pos, thread, state))
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{
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case StepResult::Matched:
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if ((pos != m_end and not (m_flags & RegexExecFlags::Search)) or
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(m_flags & RegexExecFlags::NotInitialNull and pos == m_begin))
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{
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release_saves(thread.saves);
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continue;
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}
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release_saves(m_captures);
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m_captures = thread.saves;
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found_match = true;
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// remove this and lower priority threads
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for (auto& t : state.current_threads)
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release_saves(t.saves);
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state.current_threads.clear();
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break;
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case StepResult::Failed:
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release_saves(thread.saves);
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break;
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case StepResult::Consumed:
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if (thread.inst->scheduled)
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{
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release_saves(thread.saves);
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continue;
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}
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thread.inst->scheduled = true;
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state.next_threads.push_back(thread);
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break;
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case StepResult::FindNextStart:
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state.next_threads.push_back(thread);
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find_next_start = true;
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break;
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}
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}
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for (auto& thread : state.next_threads)
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thread.inst->scheduled = false;
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if (pos == m_end or state.next_threads.empty() or
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(found_match and (m_flags & RegexExecFlags::AnyMatch)))
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{
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for (auto& t : state.next_threads)
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release_saves(t.saves);
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return found_match;
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}
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std::swap(state.current_threads, state.next_threads);
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std::reverse(state.current_threads.begin(), state.current_threads.end());
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++pos;
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if (find_next_start)
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to_next_start(pos, m_end, m_program.start_chars.get());
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}
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}
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void to_next_start(Utf8It& start, const Utf8It& end,
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const CompiledRegex::StartChars* start_chars)
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{
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if (not start_chars)
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return;
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while (start != end and *start >= 0 and
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not start_chars->map[std::min(*start, CompiledRegex::StartChars::other)])
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++start;
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}
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template<MatchDirection look_direction, bool ignore_case>
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bool lookaround(uint32_t index, Utf8It pos) const
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{
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for (auto it = m_program.lookarounds.begin() + index; *it != -1; ++it)
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{
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if (pos == (look_direction == MatchDirection::Forward ? m_end : m_begin))
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return false;
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Codepoint cp = (look_direction == MatchDirection::Forward ? *pos : *(pos-1));
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if (ignore_case)
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cp = to_lower(cp);
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const Codepoint ref = *it;
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if (ref == 0xF000)
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{} // any character matches
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else if (ref > 0xF0000 and ref <= 0xFFFFD)
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{
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if (not m_program.matchers[ref - 0xF0001](cp))
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return false;
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}
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else if (ref != cp)
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return false;
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(look_direction == MatchDirection::Forward) ? ++pos : --pos;
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}
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return true;
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}
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bool is_line_start(const Utf8It& pos) const
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{
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if (not (m_flags & RegexExecFlags::PrevAvailable) and pos == m_begin)
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return not (m_flags & RegexExecFlags::NotBeginOfLine);
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return *(pos-1) == '\n';
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}
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bool is_line_end(const Utf8It& pos) const
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{
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if (pos == m_end)
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return not (m_flags & RegexExecFlags::NotEndOfLine);
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return *pos == '\n';
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}
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bool is_word_boundary(const Utf8It& pos) const
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{
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if (not (m_flags & RegexExecFlags::PrevAvailable) and pos == m_begin)
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return not (m_flags & RegexExecFlags::NotBeginOfWord);
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if (pos == m_end)
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return not (m_flags & RegexExecFlags::NotEndOfWord);
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return is_word(*(pos-1)) != is_word(*pos);
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}
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static const Iterator& get_base(const utf8::iterator<Iterator>& it) { return it.base(); }
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static Iterator get_base(const std::reverse_iterator<utf8::iterator<Iterator>>& it) { return it.base().base(); }
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const CompiledRegex& m_program;
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Utf8It m_begin;
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Utf8It m_end;
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RegexExecFlags m_flags;
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Vector<Saves*, MemoryDomain::Regex> m_saves;
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Saves* m_first_free = nullptr;
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Saves* m_captures = nullptr;
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};
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template<typename It, MatchDirection direction = MatchDirection::Forward>
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bool regex_match(It begin, It end, const CompiledRegex& re, RegexExecFlags flags = RegexExecFlags::None)
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{
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ThreadedRegexVM<It, direction> vm{re};
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return vm.exec(begin, end, (RegexExecFlags)(flags & ~(RegexExecFlags::Search)) |
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RegexExecFlags::AnyMatch | RegexExecFlags::NoSaves);
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}
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template<typename It, MatchDirection direction = MatchDirection::Forward>
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bool regex_match(It begin, It end, Vector<It>& captures, const CompiledRegex& re,
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RegexExecFlags flags = RegexExecFlags::None)
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{
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ThreadedRegexVM<It, direction> vm{re};
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if (vm.exec(begin, end, flags & ~(RegexExecFlags::Search)))
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{
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std::copy(vm.captures().begin(), vm.captures().end(), std::back_inserter(captures));
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return true;
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}
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return false;
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}
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template<typename It, MatchDirection direction = MatchDirection::Forward>
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bool regex_search(It begin, It end, const CompiledRegex& re,
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RegexExecFlags flags = RegexExecFlags::None)
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{
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ThreadedRegexVM<It, direction> vm{re};
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return vm.exec(begin, end, flags | RegexExecFlags::Search | RegexExecFlags::AnyMatch | RegexExecFlags::NoSaves);
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}
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template<typename It, MatchDirection direction = MatchDirection::Forward>
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bool regex_search(It begin, It end, Vector<It>& captures, const CompiledRegex& re,
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RegexExecFlags flags = RegexExecFlags::None)
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|
{
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ThreadedRegexVM<It, direction> vm{re};
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if (vm.exec(begin, end, flags | RegexExecFlags::Search))
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{
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std::move(vm.captures().begin(), vm.captures().end(), std::back_inserter(captures));
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return true;
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|
}
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|
return false;
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|
}
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|
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}
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#endif // regex_impl_hh_INCLUDED
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