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authorGravatar Abseil Team <absl-team@google.com>2018-09-24 11:57:52 -0700
committerGravatar Derek Mauro <dmauro@google.com>2018-09-24 16:07:47 -0400
commite01d95528ea2137a4a27a88d1f57c6cb260aafed (patch)
tree8a766d2a0464710252cdf960789561780fd45e47 /absl/strings/internal/str_format/parser.cc
parent8ff1374008259719b54a8cb128ef951c02da164c (diff)
Export of internal Abseil changes.
-- eca34da4ccb7bb6a580f1364dff9ca053418fa3b by Abseil Team <absl-team@google.com>: Internal change. PiperOrigin-RevId: 214305433 -- 35393bdd21a87c4286f945fd34dda93afc4e0cd6 by Abseil Team <absl-team@google.com>: Move some implementation details of string_view around to facilitate compiling on NVCC. Abseil does not officially support NVCC as a reminder. PiperOrigin-RevId: 214184876 -- 61846cab9ab9476a4676ecade7173f68978cd038 by Jorg Brown <jorg@google.com>: Move the initialization values for constants back to their declaration. PiperOrigin-RevId: 214135927 -- 7ac7df6c5f78f2faf419268c04618b936cb26065 by Abseil Team <absl-team@google.com>: Performance improvements on format parser. PiperOrigin-RevId: 214032366 -- 90b4c0cf20e9feaa257a7ece40adaf7db40a60a7 by Xiaoyi Zhang <zhangxy@google.com>: Add static_assert check to absl::visit to make sure all overloads of the visitor return the same type, as required by the C++ standard. PiperOrigin-RevId: 213677001 -- 787995342101b4c181291cde9ecea3048536e4bd by Abseil Team <absl-team@google.com>: Update comment to indicate finite durations are less than InfiniteDuration. PiperOrigin-RevId: 213660328 -- d78f0dce7cc31218807e96d93b9e8513b6c80b24 by Jon Cohen <cohenjon@google.com>: s/invariant/contract in the exceptions safety testing framework. This is a better term as these can be type invariants or function post conditions. They also are very similar ground as to what is covered by c++20 Contracts (and could even be replaced by them. PiperOrigin-RevId: 213631019 -- 0b3ff1a640de9a7391a6c233568802cf86245b0e by Abseil Team <absl-team@google.com>: Add noinline attribute for GetStackTrace/GetStackFrames/... so the skipped frames will not change because of inlining difference. PiperOrigin-RevId: 213009637 GitOrigin-RevId: eca34da4ccb7bb6a580f1364dff9ca053418fa3b Change-Id: Iff1022fd24e440fcbdf3c4ab2a915ca8954daa31
Diffstat (limited to 'absl/strings/internal/str_format/parser.cc')
-rw-r--r--absl/strings/internal/str_format/parser.cc75
1 files changed, 45 insertions, 30 deletions
diff --git a/absl/strings/internal/str_format/parser.cc b/absl/strings/internal/str_format/parser.cc
index c3e16fce..5e3d0d05 100644
--- a/absl/strings/internal/str_format/parser.cc
+++ b/absl/strings/internal/str_format/parser.cc
@@ -84,16 +84,24 @@ bool ConsumeConversion(string_view *src, UnboundConversion *conv,
const char *pos = src->data();
const char *const end = pos + src->size();
char c;
- // Read the next char into `c` and update `pos`. Reads '\0' if at end.
- const auto get_char = [&] { c = pos == end ? '\0' : *pos++; };
+ // 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++; \
+ } while (0)
const auto parse_digits = [&] {
int digits = c - '0';
- // We do not want to overflow `digits` so we consume at most digits10-1
+ // 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 - 2;
- for (get_char(); num_digits && std::isdigit(c); get_char()) {
+ int num_digits = std::numeric_limits<int>::digits10;
+ for (;;) {
+ if (ABSL_PREDICT_FALSE(pos == end || !num_digits)) break;
+ c = *pos++;
+ if (!std::isdigit(c)) break;
--num_digits;
digits = 10 * digits + c - '0';
}
@@ -101,14 +109,14 @@ bool ConsumeConversion(string_view *src, UnboundConversion *conv,
};
if (is_positional) {
- get_char();
- if (c < '1' || c > '9') return false;
+ ABSL_FORMAT_PARSER_INTERNAL_GET_CHAR();
+ if (ABSL_PREDICT_FALSE(c < '1' || c > '9')) return false;
conv->arg_position = parse_digits();
assert(conv->arg_position > 0);
- if (c != '$') return false;
+ if (ABSL_PREDICT_FALSE(c != '$')) return false;
}
- get_char();
+ ABSL_FORMAT_PARSER_INTERNAL_GET_CHAR();
// We should start with the basic flag on.
assert(conv->flags.basic);
@@ -119,32 +127,39 @@ bool ConsumeConversion(string_view *src, UnboundConversion *conv,
if (c < 'A') {
conv->flags.basic = false;
- for (; c <= '0'; get_char()) {
+ 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.
switch (c) {
case '-':
conv->flags.left = true;
- continue;
+ break;
case '+':
conv->flags.show_pos = true;
- continue;
+ break;
case ' ':
conv->flags.sign_col = true;
- continue;
+ break;
case '#':
conv->flags.alt = true;
- continue;
+ break;
case '0':
conv->flags.zero = true;
- continue;
+ break;
+ default:
+ goto flags_done;
}
- break;
+ ABSL_FORMAT_PARSER_INTERNAL_GET_CHAR();
}
+flags_done:
if (c <= '9') {
if (c >= '0') {
int maybe_width = parse_digits();
if (!is_positional && c == '$') {
- if (*next_arg != 0) return false;
+ if (ABSL_PREDICT_FALSE(*next_arg != 0)) return false;
// Positional conversion.
*next_arg = -1;
conv->flags = Flags();
@@ -153,12 +168,12 @@ bool ConsumeConversion(string_view *src, UnboundConversion *conv,
}
conv->width.set_value(maybe_width);
} else if (c == '*') {
- get_char();
+ ABSL_FORMAT_PARSER_INTERNAL_GET_CHAR();
if (is_positional) {
- if (c < '1' || c > '9') return false;
+ if (ABSL_PREDICT_FALSE(c < '1' || c > '9')) return false;
conv->width.set_from_arg(parse_digits());
- if (c != '$') return false;
- get_char();
+ if (ABSL_PREDICT_FALSE(c != '$')) return false;
+ ABSL_FORMAT_PARSER_INTERNAL_GET_CHAR();
} else {
conv->width.set_from_arg(++*next_arg);
}
@@ -166,16 +181,16 @@ bool ConsumeConversion(string_view *src, UnboundConversion *conv,
}
if (c == '.') {
- get_char();
+ ABSL_FORMAT_PARSER_INTERNAL_GET_CHAR();
if (std::isdigit(c)) {
conv->precision.set_value(parse_digits());
} else if (c == '*') {
- get_char();
+ ABSL_FORMAT_PARSER_INTERNAL_GET_CHAR();
if (is_positional) {
- if (c < '1' || c > '9') return false;
+ if (ABSL_PREDICT_FALSE(c < '1' || c > '9')) return false;
conv->precision.set_from_arg(parse_digits());
if (c != '$') return false;
- get_char();
+ ABSL_FORMAT_PARSER_INTERNAL_GET_CHAR();
} else {
conv->precision.set_from_arg(++*next_arg);
}
@@ -188,23 +203,23 @@ bool ConsumeConversion(string_view *src, UnboundConversion *conv,
std::int8_t id = kIds[static_cast<unsigned char>(c)];
if (id < 0) {
- if (id == none) return false;
+ if (ABSL_PREDICT_FALSE(id == none)) return false;
// It is a length modifier.
using str_format_internal::LengthMod;
LengthMod length_mod = LengthMod::FromId(static_cast<LM>(~id));
- get_char();
+ ABSL_FORMAT_PARSER_INTERNAL_GET_CHAR();
if (c == 'h' && length_mod.id() == LengthMod::h) {
conv->length_mod = LengthMod::FromId(LengthMod::hh);
- get_char();
+ ABSL_FORMAT_PARSER_INTERNAL_GET_CHAR();
} else if (c == 'l' && length_mod.id() == LengthMod::l) {
conv->length_mod = LengthMod::FromId(LengthMod::ll);
- get_char();
+ ABSL_FORMAT_PARSER_INTERNAL_GET_CHAR();
} else {
conv->length_mod = length_mod;
}
id = kIds[static_cast<unsigned char>(c)];
- if (id < 0) return false;
+ if (ABSL_PREDICT_FALSE(id < 0)) return false;
}
assert(CheckFastPathSetting(*conv));