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-rw-r--r--absl/strings/internal/str_format/bind_test.cc9
-rw-r--r--absl/strings/internal/str_format/parser.cc143
-rw-r--r--absl/strings/internal/str_format/parser.h128
-rw-r--r--absl/strings/internal/str_format/parser_test.cc25
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 ba6470ec..2574801a 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 10487f23..9ef5615c 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 1022f062..b7614a09 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 ff705753..6d356093 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));
}
}
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