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121 lines
3.6 KiB
121 lines
3.6 KiB
1 year ago
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#include <cstring>
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#include <input.h>
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namespace {
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template<typename T>
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[[gnu::pure]]
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inline T* gmemchr(T* ptr, char ch, size_t sz) noexcept {
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return (T*)memchr((void*)ptr, ch, sz * sizeof(T));
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}
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template<typename T>
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inline size_t gmemchr_s(T* ptr, char ch, size_t sz) noexcept {
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if(T* p = gmemchr(ptr, ch, sz)) return (size_t)(p - ptr);
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else return 0;
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}
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template<typename F> requires(std::is_invocable_v<F>)
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struct Defer {
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constexpr explicit Defer(std::nullptr_t) noexcept
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: f(nullptr) {}
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constexpr Defer(F&& func) noexcept(std::is_nothrow_move_constructible_v<F>)
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: f(std::make_unique<F>(std::move(func))) {}
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constexpr virtual ~Defer() noexcept(std::is_nothrow_invocable_v<F>) { if(f) (*f)(); }
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constexpr Defer(Defer&& m) noexcept
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: f(std::move(m.f)) {}
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constexpr Defer(const Defer& p) noexcept requires(std::is_copy_constructible_v<F>)
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: f(p.f ? *p.f : nullptr) {}
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constexpr Defer& operator=(Defer&& m) noexcept(std::is_nothrow_move_constructible_v<F>)
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{
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if(this != std::addressof(m)) {
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f = std::move(m.f);
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} return *this;
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}
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constexpr Defer& operator=(const Defer& c) noexcept(std::is_nothrow_copy_constructible_v<F>) requires(std::is_copy_constructible_v<F>)
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{
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if(this != std::addressof(m)) {
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if(c.f) f = std::make_unique<F>(*c.f);
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else f = nullptr;
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} return *this;
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}
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template<typename... Args>
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constexpr decltype(auto) operator()(Args&&... args) noexcept(std::is_nothrow_invocable_v<F, Args...>) requires(std::is_invocable_v<F, Args...>)
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{ return std::forward<std::invoke_result_t<F, Args...>>( (*f)() ); }
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private:
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std::unique_ptr<F> f;
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};
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template<typename F> requires(std::is_invocable_v<F>)
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constexpr auto defer_call(F&& func) noexcept(std::is_nothrow_move_constructible_v<F>) { return Defer<F>{std::move(func)}; }
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#define $CAT_(a, b) a ## b
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#define $CAT(a, b) $CAT_(a, b)
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#define $DEFER(...) const auto $CAT(_$__defer_, __LINE__) = ::defer_call( __VA_ARGS__ )
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}
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namespace Input {
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struct Parser::_impl {
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struct {
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const char* data;
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size_t len;
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} src;
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const char* cur_line;
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size_t cur_len;
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};
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Parser::Parser(const char* string, size_t len) noexcept
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: state_(std::make_unique<_impl>())
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{
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state_->cur_line = state_->src.data = string;
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state_->cur_len = state_->src.len = len;
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}
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Parser::~Parser() {}
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Parser::Parser(Parser&& p) noexcept
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: state_(std::move(p.state_)) {}
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Parser& Parser::operator=(Parser&& p) noexcept
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{
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if(this != std::addressof(p)) {
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state_ = std::move(p.state_);
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} return *this;
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}
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bool Parser::try_read_next(Output<Line> output)
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{
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const char* start = state_->cur_line;
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const char* end = gmemchr(start, '\n', state_->cur_len);
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if(!end) return false;
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size_t diff = (size_t)(end - state_->cur_line);
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if(diff > 1) {
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auto string = std::string_view{ start, gmemchr_s(start, ' ', diff - 1) };
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for(size_t i=0;
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string.size() && string.data() < end;
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i++,
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string = std::string_view{ start += string.size(), // start = start + last size
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gmemchr_s(start, ' ', diff - 1) // XXX: <-- this should be `start + string.size()`
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})
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{
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switch(i) {
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case 0: output->start = parse_point(string); break; // First point
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case 1: continue; // Arrow
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case 2: output->end = parse_point(string); break; // Second point
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case 3: continue; // Arrow
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default: goto le; // Next point, quit
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}
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}
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le:
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end = ((const char*)string.data()) + string.size();
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state_->cur_len = (size_t)(end - state_->cur_line); // TODO: Is this the correct length calculation? I don't think it is....
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state_->cur_line = end;
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return true;
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} else return false;
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}
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}
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