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Diffstat (limited to 'src/third-party/scnlib/include/scn/detail/visitor.h')
| -rw-r--r-- | src/third-party/scnlib/include/scn/detail/visitor.h | 248 |
1 files changed, 248 insertions, 0 deletions
diff --git a/src/third-party/scnlib/include/scn/detail/visitor.h b/src/third-party/scnlib/include/scn/detail/visitor.h new file mode 100644 index 0000000..e88e2f7 --- /dev/null +++ b/src/third-party/scnlib/include/scn/detail/visitor.h @@ -0,0 +1,248 @@ +// Copyright 2017 Elias Kosunen +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// https://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. +// +// This file is a part of scnlib: +// https://github.com/eliaskosunen/scnlib + +#ifndef SCN_DETAIL_VISITOR_H +#define SCN_DETAIL_VISITOR_H + +#include "../reader/reader.h" + +namespace scn { + SCN_BEGIN_NAMESPACE + + template <typename Context, typename ParseCtx> + class basic_visitor { + public: + using context_type = Context; + using char_type = typename Context::char_type; + using arg_type = basic_arg<char_type>; + + basic_visitor(Context& ctx, ParseCtx& pctx) + : m_ctx(std::addressof(ctx)), m_pctx(std::addressof(pctx)) + { + } + + template <typename T> + auto operator()(T&& val) -> error + { + return visit(SCN_FWD(val), detail::priority_tag<1>{}); + } + + private: + auto visit(code_point& val, detail::priority_tag<1>) -> error + { + return detail::visitor_boilerplate<detail::code_point_scanner>( + val, *m_ctx, *m_pctx); + } + auto visit(span<char_type>& val, detail::priority_tag<1>) -> error + { + return detail::visitor_boilerplate<detail::span_scanner>( + val, *m_ctx, *m_pctx); + } + auto visit(bool& val, detail::priority_tag<1>) -> error + { + return detail::visitor_boilerplate<detail::bool_scanner>( + val, *m_ctx, *m_pctx); + } + +#define SCN_VISIT_INT(T) \ + error visit(T& val, detail::priority_tag<0>) \ + { \ + return detail::visitor_boilerplate<detail::integer_scanner<T>>( \ + val, *m_ctx, *m_pctx); \ + } + SCN_VISIT_INT(signed char) + SCN_VISIT_INT(short) + SCN_VISIT_INT(int) + SCN_VISIT_INT(long) + SCN_VISIT_INT(long long) + SCN_VISIT_INT(unsigned char) + SCN_VISIT_INT(unsigned short) + SCN_VISIT_INT(unsigned int) + SCN_VISIT_INT(unsigned long) + SCN_VISIT_INT(unsigned long long) + SCN_VISIT_INT(char_type) +#undef SCN_VISIT_INT + +#define SCN_VISIT_FLOAT(T) \ + error visit(T& val, detail::priority_tag<1>) \ + { \ + return detail::visitor_boilerplate<detail::float_scanner<T>>( \ + val, *m_ctx, *m_pctx); \ + } + SCN_VISIT_FLOAT(float) + SCN_VISIT_FLOAT(double) + SCN_VISIT_FLOAT(long double) +#undef SCN_VISIT_FLOAT + + auto visit(std::basic_string<char_type>& val, detail::priority_tag<1>) + -> error + { + return detail::visitor_boilerplate<detail::string_scanner>( + val, *m_ctx, *m_pctx); + } + auto visit(basic_string_view<char_type>& val, detail::priority_tag<1>) + -> error + { + return detail::visitor_boilerplate<detail::string_view_scanner>( + val, *m_ctx, *m_pctx); + } + auto visit(typename arg_type::handle val, detail::priority_tag<1>) + -> error + { + return val.scan(*m_ctx, *m_pctx); + } + [[noreturn]] auto visit(detail::monostate, detail::priority_tag<0>) + -> error + { + SCN_UNREACHABLE; + } + + Context* m_ctx; + ParseCtx* m_pctx; + }; + + template <typename Context, typename ParseCtx> + error visit(Context& ctx, + ParseCtx& pctx, + basic_args<typename Context::char_type> args) + { + using char_type = typename Context::char_type; + using arg_type = basic_arg<char_type>; + auto arg = arg_type{}; + + while (pctx) { + if (pctx.should_skip_ws()) { + // Skip whitespace from format string and from stream + // EOF is not an error + auto ret = skip_range_whitespace(ctx, false); + if (SCN_UNLIKELY(!ret)) { + if (ret == error::end_of_range) { + break; + } + SCN_CLANG_PUSH_IGNORE_UNDEFINED_TEMPLATE + auto rb = ctx.range().reset_to_rollback_point(); + if (!rb) { + return rb; + } + return ret; + } + // Don't advance pctx, should_skip_ws() does it for us + continue; + } + + // Non-brace character, or + // Brace followed by another brace, meaning a literal '{' + if (pctx.should_read_literal()) { + if (SCN_UNLIKELY(!pctx)) { + return {error::invalid_format_string, + "Unexpected end of format string"}; + } + // Check for any non-specifier {foo} characters + alignas(typename Context::char_type) unsigned char buf[4] = {0}; + auto ret = read_code_point(ctx.range(), make_span(buf, 4)); + SCN_CLANG_POP_IGNORE_UNDEFINED_TEMPLATE + if (!ret || !pctx.check_literal(ret.value().chars)) { + auto rb = ctx.range().reset_to_rollback_point(); + if (!rb) { + // Failed rollback + return rb; + } + if (!ret) { + // Failed read + return ret.error(); + } + + // Mismatching characters in scan string and stream + return {error::invalid_scanned_value, + "Expected character from format string not " + "found in the stream"}; + } + // Bump pctx to next char + if (!pctx.advance_cp()) { + pctx.advance_char(); + } + } + else { + // Scan argument + auto arg_wrapped = [&]() -> expected<arg_type> { + if (!pctx.has_arg_id()) { + return next_arg(args, pctx); + } + auto id_wrapped = pctx.parse_arg_id(); + if (!id_wrapped) { + return id_wrapped.error(); + } + auto id = id_wrapped.value(); + SCN_ENSURE(!id.empty()); + if (ctx.locale().get_static().is_digit(id.front())) { + auto s = + detail::simple_integer_scanner<std::ptrdiff_t>{}; + std::ptrdiff_t i{0}; + auto span = make_span(id.data(), id.size()); + SCN_CLANG_PUSH_IGNORE_UNDEFINED_TEMPLATE + auto ret = s.scan(span, i, 10); + SCN_CLANG_POP_IGNORE_UNDEFINED_TEMPLATE + if (!ret || ret.value() != span.end()) { + return error(error::invalid_format_string, + "Failed to parse argument id from " + "format string"); + } + return get_arg(args, pctx, i); + } + return get_arg(args, pctx, id); + }(); + if (!arg_wrapped) { + return arg_wrapped.error(); + } + arg = arg_wrapped.value(); + SCN_ENSURE(arg); + if (!pctx) { + return {error::invalid_format_string, + "Unexpected end of format argument"}; + } + auto ret = visit_arg<char_type>( + basic_visitor<Context, ParseCtx>(ctx, pctx), arg); + if (!ret) { + auto rb = ctx.range().reset_to_rollback_point(); + if (!rb) { + return rb; + } + return ret; + } + // Handle next arg and bump pctx + pctx.arg_handled(); + if (pctx) { + auto e = pctx.advance_cp(); + if (!e) { + return e; + } + } + } + } + if (pctx) { + // Format string not exhausted + return {error::invalid_format_string, + "Format string not exhausted"}; + } + ctx.range().set_rollback_point(); + return {}; + } + + SCN_END_NAMESPACE +} // namespace scn + +#endif // SCN_DETAIL_VISITOR_H |