diff options
Diffstat (limited to 'absl/strings/internal')
| -rw-r--r-- | absl/strings/internal/str_format/bind_test.cc | 9 | ||||
| -rw-r--r-- | absl/strings/internal/str_format/parser.cc | 143 | ||||
| -rw-r--r-- | absl/strings/internal/str_format/parser.h | 128 | ||||
| -rw-r--r-- | absl/strings/internal/str_format/parser_test.cc | 25 |
4 files changed, 162 insertions, 143 deletions
diff --git a/absl/strings/internal/str_format/bind_test.cc b/absl/strings/internal/str_format/bind_test.cc index ba6470ec4a36..2574801a5c38 100644 --- a/absl/strings/internal/str_format/bind_test.cc +++ b/absl/strings/internal/str_format/bind_test.cc @@ -9,16 +9,11 @@ namespace absl { namespace str_format_internal { namespace { -template <typename T, size_t N> -size_t ArraySize(T (&)[N]) { - return N; -} - class FormatBindTest : public ::testing::Test { public: bool Extract(const char *s, UnboundConversion *props, int *next) const { - absl::string_view src = s; - return ConsumeUnboundConversion(&src, props, next) && src.empty(); + return ConsumeUnboundConversion(s, s + strlen(s), props, next) == + s + strlen(s); } }; diff --git a/absl/strings/internal/str_format/parser.cc b/absl/strings/internal/str_format/parser.cc index 10487f23c855..9ef5615cc9ee 100644 --- a/absl/strings/internal/str_format/parser.cc +++ b/absl/strings/internal/str_format/parser.cc @@ -15,6 +15,44 @@ namespace absl { namespace str_format_internal { + +using CC = ConversionChar::Id; +using LM = LengthMod::Id; +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) { @@ -36,60 +74,17 @@ bool CheckFastPathSetting(const UnboundConversion& conv) { return should_be_basic == conv.flags.basic; } -// Keep a single table for all the conversion chars and length modifiers. -// We invert the length modifiers to make them negative so that we can easily -// test for them. -// Everything else is `none`, which is a negative constant. -using CC = ConversionChar::Id; -using LM = LengthMod::Id; -static constexpr std::int8_t none = -128; -static constexpr std::int8_t kIds[] = { - none, none, none, none, none, none, none, none, // 00-07 - none, none, none, none, none, none, none, none, // 08-0f - none, none, none, none, none, none, none, none, // 10-17 - none, none, none, none, none, none, none, none, // 18-1f - none, none, none, none, none, none, none, none, // 20-27 - none, none, none, none, none, none, none, none, // 28-2f - none, none, none, none, none, none, none, none, // 30-37 - none, none, none, none, none, none, none, none, // 38-3f - none, CC::A, none, CC::C, none, CC::E, CC::F, CC::G, // @ABCDEFG - none, none, none, none, ~LM::L, none, none, none, // HIJKLMNO - none, none, none, CC::S, none, none, none, none, // PQRSTUVW - CC::X, none, none, none, none, none, none, none, // XYZ[\]^_ - none, CC::a, none, CC::c, CC::d, CC::e, CC::f, CC::g, // `abcdefg - ~LM::h, CC::i, ~LM::j, none, ~LM::l, none, CC::n, CC::o, // hijklmno - CC::p, ~LM::q, none, CC::s, ~LM::t, CC::u, none, none, // pqrstuvw - CC::x, none, ~LM::z, none, none, none, none, none, // xyz{|}~! - none, none, none, none, none, none, none, none, // 80-87 - none, none, none, none, none, none, none, none, // 88-8f - none, none, none, none, none, none, none, none, // 90-97 - none, none, none, none, none, none, none, none, // 98-9f - none, none, none, none, none, none, none, none, // a0-a7 - none, none, none, none, none, none, none, none, // a8-af - none, none, none, none, none, none, none, none, // b0-b7 - none, none, none, none, none, none, none, none, // b8-bf - none, none, none, none, none, none, none, none, // c0-c7 - none, none, none, none, none, none, none, none, // c8-cf - none, none, none, none, none, none, none, none, // d0-d7 - none, none, none, none, none, none, none, none, // d8-df - none, none, none, none, none, none, none, none, // e0-e7 - none, none, none, none, none, none, none, none, // e8-ef - none, none, none, none, none, none, none, none, // f0-f7 - none, none, none, none, none, none, none, none, // f8-ff -}; - template <bool is_positional> -bool ConsumeConversion(string_view *src, UnboundConversion *conv, - int *next_arg) { - const char *pos = src->data(); - const char *const end = pos + src->size(); +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 false; \ - c = *pos++; \ +#define ABSL_FORMAT_PARSER_INTERNAL_GET_CHAR() \ + do { \ + if (ABSL_PREDICT_FALSE(pos == end)) return nullptr; \ + c = *pos++; \ } while (0) const auto parse_digits = [&] { @@ -111,10 +106,10 @@ bool ConsumeConversion(string_view *src, UnboundConversion *conv, if (is_positional) { ABSL_FORMAT_PARSER_INTERNAL_GET_CHAR(); - if (ABSL_PREDICT_FALSE(c < '1' || c > '9')) return false; + 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 != '$')) return false; + if (ABSL_PREDICT_FALSE(c != '$')) return nullptr; } ABSL_FORMAT_PARSER_INTERNAL_GET_CHAR(); @@ -129,10 +124,9 @@ bool ConsumeConversion(string_view *src, UnboundConversion *conv, conv->flags.basic = false; for (; c <= '0';) { - // FIXME: We might be able to speed this up reusing the kIds lookup table - // from above. - // It might require changing Flags to be a plain integer where we can |= a - // value. + // 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; @@ -160,20 +154,20 @@ flags_done: if (c >= '0') { int maybe_width = parse_digits(); if (!is_positional && c == '$') { - if (ABSL_PREDICT_FALSE(*next_arg != 0)) return false; + if (ABSL_PREDICT_FALSE(*next_arg != 0)) return nullptr; // Positional conversion. *next_arg = -1; conv->flags = Flags(); conv->flags.basic = true; - return ConsumeConversion<true>(src, conv, next_arg); + return ConsumeConversion<true>(original_pos, end, conv, next_arg); } conv->width.set_value(maybe_width); } else if (c == '*') { ABSL_FORMAT_PARSER_INTERNAL_GET_CHAR(); if (is_positional) { - if (ABSL_PREDICT_FALSE(c < '1' || c > '9')) return false; + if (ABSL_PREDICT_FALSE(c < '1' || c > '9')) return nullptr; conv->width.set_from_arg(parse_digits()); - if (ABSL_PREDICT_FALSE(c != '$')) return false; + if (ABSL_PREDICT_FALSE(c != '$')) return nullptr; ABSL_FORMAT_PARSER_INTERNAL_GET_CHAR(); } else { conv->width.set_from_arg(++*next_arg); @@ -188,9 +182,9 @@ flags_done: } else if (c == '*') { ABSL_FORMAT_PARSER_INTERNAL_GET_CHAR(); if (is_positional) { - if (ABSL_PREDICT_FALSE(c < '1' || c > '9')) return false; + if (ABSL_PREDICT_FALSE(c < '1' || c > '9')) return nullptr; conv->precision.set_from_arg(parse_digits()); - if (c != '$') return false; + if (c != '$') return nullptr; ABSL_FORMAT_PARSER_INTERNAL_GET_CHAR(); } else { conv->precision.set_from_arg(++*next_arg); @@ -201,14 +195,14 @@ flags_done: } } - std::int8_t id = kIds[static_cast<unsigned char>(c)]; + auto tag = GetTagForChar(c); - if (id < 0) { - if (ABSL_PREDICT_FALSE(id == none)) return false; + 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 = LengthMod::FromId(static_cast<LM>(~id)); + LengthMod length_mod = tag.as_length(); ABSL_FORMAT_PARSER_INTERNAL_GET_CHAR(); if (c == 'h' && length_mod.id() == LengthMod::h) { conv->length_mod = LengthMod::FromId(LengthMod::hh); @@ -219,25 +213,24 @@ flags_done: } else { conv->length_mod = length_mod; } - id = kIds[static_cast<unsigned char>(c)]; - if (ABSL_PREDICT_FALSE(id < 0)) return false; + tag = GetTagForChar(c); + if (ABSL_PREDICT_FALSE(!tag.is_conv())) return nullptr; } assert(CheckFastPathSetting(*conv)); (void)(&CheckFastPathSetting); - conv->conv = ConversionChar::FromId(static_cast<CC>(id)); + conv->conv = tag.as_conv(); if (!is_positional) conv->arg_position = ++*next_arg; - *src = string_view(pos, end - pos); - return true; + return pos; } } // namespace -bool ConsumeUnboundConversion(string_view *src, UnboundConversion *conv, - int *next_arg) { - if (*next_arg < 0) return ConsumeConversion<true>(src, conv, next_arg); - return ConsumeConversion<false>(src, conv, next_arg); +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 { diff --git a/absl/strings/internal/str_format/parser.h b/absl/strings/internal/str_format/parser.h index 1022f06297a7..b7614a09fa4e 100644 --- a/absl/strings/internal/str_format/parser.h +++ b/absl/strings/internal/str_format/parser.h @@ -63,17 +63,45 @@ struct UnboundConversion { ConversionChar conv; }; -// Consume conversion spec prefix (not including '%') of '*src' if valid. +// Consume conversion spec prefix (not including '%') of [p, end) if valid. // Examples of valid specs would be e.g.: "s", "d", "-12.6f". -// If valid, the front of src is advanced such that src becomes the -// part following the conversion spec, and the spec part is broken down and -// returned in 'conv'. -// If invalid, returns false and leaves 'src' unmodified. -// For example: -// Given "d9", returns "d", and leaves src="9", -// Given "!", returns "" and leaves src="!". -bool ConsumeUnboundConversion(string_view* src, UnboundConversion* conv, - int* next_arg); +// If valid, it returns the first character following the conversion spec, +// and the spec part is broken down and returned in 'conv'. +// If invalid, returns nullptr. +const char* ConsumeUnboundConversion(const char* p, const char* end, + UnboundConversion* conv, int* next_arg); + +// Helper tag class for the table below. +// It allows fast `char -> ConversionChar/LengthMod` checking and conversions. +class ConvTag { + public: + constexpr ConvTag(ConversionChar::Id id) : tag_(id) {} // NOLINT + // We invert the length modifiers to make them negative so that we can easily + // test for them. + constexpr ConvTag(LengthMod::Id id) : tag_(~id) {} // NOLINT + // Everything else is -128, which is negative to make is_conv() simpler. + constexpr ConvTag() : tag_(-128) {} + + bool is_conv() const { return tag_ >= 0; } + bool is_length() const { return tag_ < 0 && tag_ != -128; } + ConversionChar as_conv() const { + assert(is_conv()); + return ConversionChar::FromId(static_cast<ConversionChar::Id>(tag_)); + } + LengthMod as_length() const { + assert(is_length()); + return LengthMod::FromId(static_cast<LengthMod::Id>(~tag_)); + } + + private: + std::int8_t tag_; +}; + +extern const ConvTag kTags[256]; +// Keep a single table for all the conversion chars and length modifiers. +inline ConvTag GetTagForChar(char c) { + return kTags[static_cast<unsigned char>(c)]; +} // Parse the format string provided in 'src' and pass the identified items into // 'consumer'. @@ -88,51 +116,53 @@ bool ConsumeUnboundConversion(string_view* src, UnboundConversion* conv, template <typename Consumer> bool ParseFormatString(string_view src, Consumer consumer) { int next_arg = 0; - while (!src.empty()) { - const char* percent = - static_cast<const char*>(memchr(src.data(), '%', src.size())); + const char* p = src.data(); + const char* const end = p + src.size(); + while (p != end) { + const char* percent = static_cast<const char*>(memchr(p, '%', end - p)); if (!percent) { // We found the last substring. - return consumer.Append(src); + return consumer.Append(string_view(p, end - p)); } // We found a percent, so push the text run then process the percent. - size_t percent_loc = percent - src.data(); - if (!consumer.Append(string_view(src.data(), percent_loc))) return false; - if (percent + 1 >= src.data() + src.size()) return false; - - UnboundConversion conv; - - switch (percent[1]) { - case '%': - if (!consumer.Append("%")) return false; - src.remove_prefix(percent_loc + 2); - continue; - -#define PARSER_CASE(ch) \ - case #ch[0]: \ - src.remove_prefix(percent_loc + 2); \ - conv.conv = ConversionChar::FromId(ConversionChar::ch); \ - conv.arg_position = ++next_arg; \ - break; - ABSL_CONVERSION_CHARS_EXPAND_(PARSER_CASE, ); -#undef PARSER_CASE - - default: - src.remove_prefix(percent_loc + 1); - if (!ConsumeUnboundConversion(&src, &conv, &next_arg)) return false; - break; - } - if (next_arg == 0) { - // This indicates an error in the format std::string. - // The only way to get next_arg == 0 is to have a positional argument - // first which sets next_arg to -1 and then a non-positional argument - // which does ++next_arg. - // Checking here seems to be the cheapeast place to do it. + if (ABSL_PREDICT_FALSE(!consumer.Append(string_view(p, percent - p)))) { return false; } - if (!consumer.ConvertOne( - conv, string_view(percent + 1, src.data() - (percent + 1)))) { - return false; + if (ABSL_PREDICT_FALSE(percent + 1 >= end)) return false; + + auto tag = GetTagForChar(percent[1]); + if (tag.is_conv()) { + if (ABSL_PREDICT_FALSE(next_arg < 0)) { + // This indicates an error in the format std::string. + // The only way to get `next_arg < 0` here is to have a positional + // argument first which sets next_arg to -1 and then a non-positional + // argument. + return false; + } + p = percent + 2; + + // Keep this case separate from the one below. + // ConvertOne is more efficient when the compiler can see that the `basic` + // flag is set. + UnboundConversion conv; + conv.conv = tag.as_conv(); + conv.arg_position = ++next_arg; + if (ABSL_PREDICT_FALSE( + !consumer.ConvertOne(conv, string_view(percent + 1, 1)))) { + return false; + } + } else if (percent[1] != '%') { + UnboundConversion conv; + p = ConsumeUnboundConversion(percent + 1, end, &conv, &next_arg); + if (ABSL_PREDICT_FALSE(p == nullptr)) return false; + if (ABSL_PREDICT_FALSE(!consumer.ConvertOne( + conv, string_view(percent + 1, p - (percent + 1))))) { + return false; + } + } else { + if (ABSL_PREDICT_FALSE(!consumer.Append("%"))) return false; + p = percent + 2; + continue; } } return true; diff --git a/absl/strings/internal/str_format/parser_test.cc b/absl/strings/internal/str_format/parser_test.cc index ff7057534f43..6d356093ce60 100644 --- a/absl/strings/internal/str_format/parser_test.cc +++ b/absl/strings/internal/str_format/parser_test.cc @@ -1,6 +1,8 @@ #include "absl/strings/internal/str_format/parser.h" #include <string.h> + +#include "gmock/gmock.h" #include "gtest/gtest.h" #include "absl/base/macros.h" @@ -9,6 +11,8 @@ namespace str_format_internal { namespace { +using testing::Pair; + TEST(LengthModTest, Names) { struct Expectation { int line; @@ -63,20 +67,21 @@ TEST(ConversionCharTest, Names) { class ConsumeUnboundConversionTest : public ::testing::Test { public: - typedef UnboundConversion Props; - string_view Consume(string_view* src) { + std::pair<string_view, string_view> Consume(string_view src) { int next = 0; - const char* prev_begin = src->data(); o = UnboundConversion(); // refresh - ConsumeUnboundConversion(src, &o, &next); - return {prev_begin, static_cast<size_t>(src->data() - prev_begin)}; + const char* p = ConsumeUnboundConversion( + src.data(), src.data() + src.size(), &o, &next); + if (!p) return {{}, src}; + return {string_view(src.data(), p - src.data()), + string_view(p, src.data() + src.size() - p)}; } bool Run(const char *fmt, bool force_positional = false) { - string_view src = fmt; int next = force_positional ? -1 : 0; o = UnboundConversion(); // refresh - return ConsumeUnboundConversion(&src, &o, &next) && src.empty(); + return ConsumeUnboundConversion(fmt, fmt + strlen(fmt), &o, &next) == + fmt + strlen(fmt); } UnboundConversion o; }; @@ -104,11 +109,7 @@ TEST_F(ConsumeUnboundConversionTest, ConsumeSpecification) { }; for (const auto& e : kExpect) { SCOPED_TRACE(e.line); - string_view src = e.src; - EXPECT_EQ(e.src, src); - string_view out = Consume(&src); - EXPECT_EQ(e.out, out); - EXPECT_EQ(e.src_post, src); + EXPECT_THAT(Consume(e.src), Pair(e.out, e.src_post)); } } |