diff options
Diffstat (limited to 'third_party/abseil-cpp/absl/strings/internal/str_format/parser.cc')
| -rw-r--r-- | third_party/abseil-cpp/absl/strings/internal/str_format/parser.cc | 334 |
1 files changed, 334 insertions, 0 deletions
diff --git a/third_party/abseil-cpp/absl/strings/internal/str_format/parser.cc b/third_party/abseil-cpp/absl/strings/internal/str_format/parser.cc new file mode 100644 index 0000000000..aab68db94b --- /dev/null +++ b/third_party/abseil-cpp/absl/strings/internal/str_format/parser.cc @@ -0,0 +1,334 @@ +#include "absl/strings/internal/str_format/parser.h" + +#include <assert.h> +#include <string.h> +#include <wchar.h> +#include <cctype> +#include <cstdint> + +#include <algorithm> +#include <initializer_list> +#include <limits> +#include <ostream> +#include <string> +#include <unordered_set> + +namespace absl { +ABSL_NAMESPACE_BEGIN +namespace str_format_internal { + +using CC = ConversionChar; +using LM = LengthMod; + +ABSL_CONST_INIT const ConvTag kTags[256] = { + {}, {}, {}, {}, {}, {}, {}, {}, // 00-07 + {}, {}, {}, {}, {}, {}, {}, {}, // 08-0f + {}, {}, {}, {}, {}, {}, {}, {}, // 10-17 + {}, {}, {}, {}, {}, {}, {}, {}, // 18-1f + {}, {}, {}, {}, {}, {}, {}, {}, // 20-27 + {}, {}, {}, {}, {}, {}, {}, {}, // 28-2f + {}, {}, {}, {}, {}, {}, {}, {}, // 30-37 + {}, {}, {}, {}, {}, {}, {}, {}, // 38-3f + {}, CC::A, {}, CC::C, {}, CC::E, CC::F, CC::G, // @ABCDEFG + {}, {}, {}, {}, LM::L, {}, {}, {}, // HIJKLMNO + {}, {}, {}, CC::S, {}, {}, {}, {}, // PQRSTUVW + CC::X, {}, {}, {}, {}, {}, {}, {}, // XYZ[\]^_ + {}, CC::a, {}, CC::c, CC::d, CC::e, CC::f, CC::g, // `abcdefg + LM::h, CC::i, LM::j, {}, LM::l, {}, CC::n, CC::o, // hijklmno + CC::p, LM::q, {}, CC::s, LM::t, CC::u, {}, {}, // pqrstuvw + CC::x, {}, LM::z, {}, {}, {}, {}, {}, // xyz{|}! + {}, {}, {}, {}, {}, {}, {}, {}, // 80-87 + {}, {}, {}, {}, {}, {}, {}, {}, // 88-8f + {}, {}, {}, {}, {}, {}, {}, {}, // 90-97 + {}, {}, {}, {}, {}, {}, {}, {}, // 98-9f + {}, {}, {}, {}, {}, {}, {}, {}, // a0-a7 + {}, {}, {}, {}, {}, {}, {}, {}, // a8-af + {}, {}, {}, {}, {}, {}, {}, {}, // b0-b7 + {}, {}, {}, {}, {}, {}, {}, {}, // b8-bf + {}, {}, {}, {}, {}, {}, {}, {}, // c0-c7 + {}, {}, {}, {}, {}, {}, {}, {}, // c8-cf + {}, {}, {}, {}, {}, {}, {}, {}, // d0-d7 + {}, {}, {}, {}, {}, {}, {}, {}, // d8-df + {}, {}, {}, {}, {}, {}, {}, {}, // e0-e7 + {}, {}, {}, {}, {}, {}, {}, {}, // e8-ef + {}, {}, {}, {}, {}, {}, {}, {}, // f0-f7 + {}, {}, {}, {}, {}, {}, {}, {}, // f8-ff +}; + +namespace { + +bool CheckFastPathSetting(const UnboundConversion& conv) { + bool should_be_basic = !conv.flags.left && // + !conv.flags.show_pos && // + !conv.flags.sign_col && // + !conv.flags.alt && // + !conv.flags.zero && // + (conv.width.value() == -1) && + (conv.precision.value() == -1); + if (should_be_basic != conv.flags.basic) { + fprintf(stderr, + "basic=%d left=%d show_pos=%d sign_col=%d alt=%d zero=%d " + "width=%d precision=%d\n", + conv.flags.basic, conv.flags.left, conv.flags.show_pos, + conv.flags.sign_col, conv.flags.alt, conv.flags.zero, + conv.width.value(), conv.precision.value()); + } + return should_be_basic == conv.flags.basic; +} + +template <bool is_positional> +const char *ConsumeConversion(const char *pos, const char *const end, + UnboundConversion *conv, int *next_arg) { + const char* const original_pos = pos; + char c; + // Read the next char into `c` and update `pos`. Returns false if there are + // no more chars to read. +#define ABSL_FORMAT_PARSER_INTERNAL_GET_CHAR() \ + do { \ + if (ABSL_PREDICT_FALSE(pos == end)) return nullptr; \ + c = *pos++; \ + } while (0) + + const auto parse_digits = [&] { + int digits = c - '0'; + // We do not want to overflow `digits` so we consume at most digits10 + // digits. If there are more digits the parsing will fail later on when the + // digit doesn't match the expected characters. + int num_digits = std::numeric_limits<int>::digits10; + for (;;) { + if (ABSL_PREDICT_FALSE(pos == end)) break; + c = *pos++; + if (!std::isdigit(c)) break; + --num_digits; + if (ABSL_PREDICT_FALSE(!num_digits)) break; + digits = 10 * digits + c - '0'; + } + return digits; + }; + + if (is_positional) { + ABSL_FORMAT_PARSER_INTERNAL_GET_CHAR(); + if (ABSL_PREDICT_FALSE(c < '1' || c > '9')) return nullptr; + conv->arg_position = parse_digits(); + assert(conv->arg_position > 0); + if (ABSL_PREDICT_FALSE(c != '$')) return nullptr; + } + + ABSL_FORMAT_PARSER_INTERNAL_GET_CHAR(); + + // We should start with the basic flag on. + assert(conv->flags.basic); + + // Any non alpha character makes this conversion not basic. + // This includes flags (-+ #0), width (1-9, *) or precision (.). + // All conversion characters and length modifiers are alpha characters. + if (c < 'A') { + conv->flags.basic = false; + + for (; c <= '0';) { + // FIXME: We might be able to speed this up reusing the lookup table from + // above. It might require changing Flags to be a plain integer where we + // can |= a value. + switch (c) { + case '-': + conv->flags.left = true; + break; + case '+': + conv->flags.show_pos = true; + break; + case ' ': + conv->flags.sign_col = true; + break; + case '#': + conv->flags.alt = true; + break; + case '0': + conv->flags.zero = true; + break; + default: + goto flags_done; + } + ABSL_FORMAT_PARSER_INTERNAL_GET_CHAR(); + } +flags_done: + + if (c <= '9') { + if (c >= '0') { + int maybe_width = parse_digits(); + if (!is_positional && c == '$') { + if (ABSL_PREDICT_FALSE(*next_arg != 0)) return nullptr; + // Positional conversion. + *next_arg = -1; + conv->flags = Flags(); + conv->flags.basic = true; + return ConsumeConversion<true>(original_pos, end, conv, next_arg); + } + conv->width.set_value(maybe_width); + } else if (c == '*') { + ABSL_FORMAT_PARSER_INTERNAL_GET_CHAR(); + if (is_positional) { + if (ABSL_PREDICT_FALSE(c < '1' || c > '9')) return nullptr; + conv->width.set_from_arg(parse_digits()); + if (ABSL_PREDICT_FALSE(c != '$')) return nullptr; + ABSL_FORMAT_PARSER_INTERNAL_GET_CHAR(); + } else { + conv->width.set_from_arg(++*next_arg); + } + } + } + + if (c == '.') { + ABSL_FORMAT_PARSER_INTERNAL_GET_CHAR(); + if (std::isdigit(c)) { + conv->precision.set_value(parse_digits()); + } else if (c == '*') { + ABSL_FORMAT_PARSER_INTERNAL_GET_CHAR(); + if (is_positional) { + if (ABSL_PREDICT_FALSE(c < '1' || c > '9')) return nullptr; + conv->precision.set_from_arg(parse_digits()); + if (c != '$') return nullptr; + ABSL_FORMAT_PARSER_INTERNAL_GET_CHAR(); + } else { + conv->precision.set_from_arg(++*next_arg); + } + } else { + conv->precision.set_value(0); + } + } + } + + auto tag = GetTagForChar(c); + + if (ABSL_PREDICT_FALSE(!tag.is_conv())) { + if (ABSL_PREDICT_FALSE(!tag.is_length())) return nullptr; + + // It is a length modifier. + using str_format_internal::LengthMod; + LengthMod length_mod = tag.as_length(); + ABSL_FORMAT_PARSER_INTERNAL_GET_CHAR(); + if (c == 'h' && length_mod == LengthMod::h) { + conv->length_mod = LengthMod::hh; + ABSL_FORMAT_PARSER_INTERNAL_GET_CHAR(); + } else if (c == 'l' && length_mod == LengthMod::l) { + conv->length_mod = LengthMod::ll; + ABSL_FORMAT_PARSER_INTERNAL_GET_CHAR(); + } else { + conv->length_mod = length_mod; + } + tag = GetTagForChar(c); + if (ABSL_PREDICT_FALSE(!tag.is_conv())) return nullptr; + } + + assert(CheckFastPathSetting(*conv)); + (void)(&CheckFastPathSetting); + + conv->conv = tag.as_conv(); + if (!is_positional) conv->arg_position = ++*next_arg; + return pos; +} + +} // namespace + +std::string LengthModToString(LengthMod v) { + switch (v) { + case LengthMod::h: + return "h"; + case LengthMod::hh: + return "hh"; + case LengthMod::l: + return "l"; + case LengthMod::ll: + return "ll"; + case LengthMod::L: + return "L"; + case LengthMod::j: + return "j"; + case LengthMod::z: + return "z"; + case LengthMod::t: + return "t"; + case LengthMod::q: + return "q"; + case LengthMod::none: + return ""; + } + return ""; +} + +const char *ConsumeUnboundConversion(const char *p, const char *end, + UnboundConversion *conv, int *next_arg) { + if (*next_arg < 0) return ConsumeConversion<true>(p, end, conv, next_arg); + return ConsumeConversion<false>(p, end, conv, next_arg); +} + +struct ParsedFormatBase::ParsedFormatConsumer { + explicit ParsedFormatConsumer(ParsedFormatBase *parsedformat) + : parsed(parsedformat), data_pos(parsedformat->data_.get()) {} + + bool Append(string_view s) { + if (s.empty()) return true; + + size_t text_end = AppendText(s); + + if (!parsed->items_.empty() && !parsed->items_.back().is_conversion) { + // Let's extend the existing text run. + parsed->items_.back().text_end = text_end; + } else { + // Let's make a new text run. + parsed->items_.push_back({false, text_end, {}}); + } + return true; + } + + bool ConvertOne(const UnboundConversion &conv, string_view s) { + size_t text_end = AppendText(s); + parsed->items_.push_back({true, text_end, conv}); + return true; + } + + size_t AppendText(string_view s) { + memcpy(data_pos, s.data(), s.size()); + data_pos += s.size(); + return static_cast<size_t>(data_pos - parsed->data_.get()); + } + + ParsedFormatBase *parsed; + char* data_pos; +}; + +ParsedFormatBase::ParsedFormatBase(string_view format, bool allow_ignored, + std::initializer_list<Conv> convs) + : data_(format.empty() ? nullptr : new char[format.size()]) { + has_error_ = !ParseFormatString(format, ParsedFormatConsumer(this)) || + !MatchesConversions(allow_ignored, convs); +} + +bool ParsedFormatBase::MatchesConversions( + bool allow_ignored, std::initializer_list<Conv> convs) const { + std::unordered_set<int> used; + auto add_if_valid_conv = [&](int pos, char c) { + if (static_cast<size_t>(pos) > convs.size() || + !Contains(convs.begin()[pos - 1], c)) + return false; + used.insert(pos); + return true; + }; + for (const ConversionItem &item : items_) { + if (!item.is_conversion) continue; + auto &conv = item.conv; + if (conv.precision.is_from_arg() && + !add_if_valid_conv(conv.precision.get_from_arg(), '*')) + return false; + if (conv.width.is_from_arg() && + !add_if_valid_conv(conv.width.get_from_arg(), '*')) + return false; + if (!add_if_valid_conv(conv.arg_position, + FormatConversionCharToChar(conv.conv))) + return false; + } + return used.size() == convs.size() || allow_ignored; +} + +} // namespace str_format_internal +ABSL_NAMESPACE_END +} // namespace absl |