Add sentinel support
This commit is contained in:
Victor Zverovich
parent
13fa26745d
commit
c068c7c622
66
test/scan.h
66
test/scan.h
@ -65,29 +65,31 @@ class scan_buffer {
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// Fills the buffer with more input if available.
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virtual void consume() = 0;
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class sentinel {};
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class iterator {
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private:
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const char** ptr_;
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scan_buffer* buf_; // This could be merged with ptr_.
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char value_;
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static auto sentinel() -> const char** {
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static auto get_sentinel() -> const char** {
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static const char* ptr = nullptr;
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return &ptr;
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}
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friend class scan_buffer;
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friend auto operator==(iterator lhs, iterator rhs) -> bool {
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return *lhs.ptr_ == *rhs.ptr_;
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friend auto operator==(iterator lhs, sentinel) -> bool {
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return *lhs.ptr_ == nullptr;
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}
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friend auto operator!=(iterator lhs, iterator rhs) -> bool {
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return *lhs.ptr_ != *rhs.ptr_;
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friend auto operator!=(iterator lhs, sentinel) -> bool {
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return *lhs.ptr_ != nullptr;
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}
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iterator(scan_buffer* buf) : buf_(buf) {
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if (buf->ptr_ == buf->end_) {
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ptr_ = sentinel();
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ptr_ = get_sentinel();
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return;
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}
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ptr_ = &buf->ptr_;
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@ -97,10 +99,10 @@ class scan_buffer {
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friend scan_buffer& get_buffer(iterator it) { return *it.buf_; }
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public:
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iterator() : ptr_(sentinel()), buf_(nullptr) {}
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iterator() : ptr_(get_sentinel()), buf_(nullptr) {}
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auto operator++() -> iterator& {
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if (!buf_->try_consume()) ptr_ = sentinel();
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if (!buf_->try_consume()) ptr_ = get_sentinel();
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value_ = *buf_->ptr_;
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return *this;
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}
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@ -126,12 +128,12 @@ class scan_buffer {
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const char*& ptr = it.buf_->ptr_;
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ptr += n;
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it.value_ = *ptr;
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if (ptr == it.buf_->end_) it.ptr_ = iterator::sentinel();
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if (ptr == it.buf_->end_) it.ptr_ = iterator::get_sentinel();
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return it;
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}
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auto begin() -> iterator { return this; }
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auto end() -> iterator { return {}; }
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auto end() -> sentinel { return {}; }
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auto is_contiguous() const -> bool { return contiguous_; }
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@ -422,6 +424,7 @@ class scan_context {
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public:
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using iterator = detail::scan_buffer::iterator;
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using sentinel = detail::scan_buffer::sentinel;
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explicit FMT_CONSTEXPR scan_context(detail::scan_buffer& buf, scan_args args)
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: buf_(buf), args_(args) {}
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@ -431,7 +434,7 @@ class scan_context {
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}
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auto begin() const -> iterator { return buf_.begin(); }
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auto end() const -> iterator { return buf_.end(); }
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auto end() const -> sentinel { return {}; }
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void advance_to(iterator) { buf_.consume(); }
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};
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@ -442,7 +445,7 @@ const char* parse_scan_specs(const char* begin, const char* end,
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format_specs<>& specs, scan_type) {
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while (begin != end) {
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switch (to_ascii(*begin)) {
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// TODO: parse scan format specifiers
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// TODO: parse more scan format specifiers
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case 'x':
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specs.type = presentation_type::hex_lower;
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break;
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@ -454,14 +457,14 @@ const char* parse_scan_specs(const char* begin, const char* end,
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}
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struct default_arg_scanner {
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// TODO: storing a range can be more efficient
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using iterator = scan_buffer::iterator;
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using sentinel = scan_buffer::sentinel;
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iterator begin;
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iterator end;
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template <typename T = unsigned>
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auto read_uint(iterator it, T& value) -> iterator {
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if (it == end) return it;
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if (it == sentinel()) return it;
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char c = *it;
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if (c < '0' || c > '9') throw_format_error("invalid input");
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@ -475,7 +478,7 @@ struct default_arg_scanner {
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c = *++it;
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++num_digits;
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if (c < '0' || c > '9') break;
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} while (it != end);
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} while (it != sentinel());
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// Check overflow.
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if (num_digits <= std::numeric_limits<int>::digits10) {
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@ -494,10 +497,10 @@ struct default_arg_scanner {
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template <typename T = int>
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auto read_int(iterator it, T& value) -> iterator {
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bool negative = it != end && *it == '-';
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bool negative = it != sentinel() && *it == '-';
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if (negative) {
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++it;
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if (it == end) throw_format_error("invalid input");
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if (it == sentinel()) throw_format_error("invalid input");
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}
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using unsigned_type = typename std::make_unsigned<T>::type;
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unsigned_type abs_value = 0;
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@ -521,7 +524,7 @@ struct default_arg_scanner {
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}
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auto operator()(std::string& value) -> iterator {
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iterator it = begin;
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while (it != end && *it != ' ') value.push_back(*it++);
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while (it != sentinel() && *it != ' ') value.push_back(*it++);
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return it;
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}
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auto operator()(fmt::string_view& value) -> iterator {
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@ -541,12 +544,18 @@ struct default_arg_scanner {
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struct arg_scanner {
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using iterator = scan_buffer::iterator;
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using sentinel = scan_buffer::sentinel;
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iterator begin;
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iterator end;
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const format_specs<>& specs;
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template <typename T>
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template <typename T, FMT_ENABLE_IF(std::is_integral<T>::value)>
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auto operator()(T&&) -> iterator {
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// TODO: implement
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return begin;
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}
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template <typename T, FMT_ENABLE_IF(!std::is_integral<T>::value)>
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auto operator()(T&&) -> iterator {
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// TODO: implement
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return begin;
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@ -559,6 +568,8 @@ struct scan_handler : error_handler {
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scan_context scan_ctx_;
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int next_arg_id_;
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using sentinel = scan_buffer::sentinel;
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public:
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FMT_CONSTEXPR scan_handler(string_view format, scan_buffer& buf,
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scan_args args)
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@ -568,9 +579,9 @@ struct scan_handler : error_handler {
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void on_text(const char* begin, const char* end) {
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if (begin == end) return;
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auto it = scan_ctx_.begin(), scan_end = scan_ctx_.end();
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auto it = scan_ctx_.begin();
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for (; begin != end; ++begin, ++it) {
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if (it == scan_end || *begin != *it) on_error("invalid input");
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if (it == sentinel() || *begin != *it) on_error("invalid input");
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}
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scan_ctx_.advance_to(it);
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}
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@ -587,9 +598,9 @@ struct scan_handler : error_handler {
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void on_replacement_field(int arg_id, const char*) {
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scan_arg arg = scan_ctx_.arg(arg_id);
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auto it = scan_ctx_.begin(), end = scan_ctx_.end();
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while (it != end && is_whitespace(*it)) ++it;
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scan_ctx_.advance_to(arg.visit(default_arg_scanner{it, end}));
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auto it = scan_ctx_.begin();
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while (it != sentinel() && is_whitespace(*it)) ++it;
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scan_ctx_.advance_to(arg.visit(default_arg_scanner{it}));
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}
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auto on_format_specs(int arg_id, const char* begin, const char* end) -> const
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@ -600,13 +611,12 @@ struct scan_handler : error_handler {
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auto specs = format_specs<>();
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begin = parse_scan_specs(begin, end, specs, arg.type());
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if (begin == end || *begin != '}') on_error("missing '}' in format string");
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auto s = arg_scanner{scan_ctx_.begin(), scan_ctx_.end(), specs};
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auto s = arg_scanner{scan_ctx_.begin(), specs};
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scan_ctx_.advance_to(arg.visit(s));
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return begin;
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}
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void on_error(const char* message) {
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scan_ctx_.advance_to(scan_ctx_.end());
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error_handler::on_error(message);
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}
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};
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