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f28d30df5769bb832dec3ff36d2fcd2bcdf494a3 by Shaindel Schwartz <shaindel@google.com>:

Internal change

PiperOrigin-RevId: 201046831

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711715a78b7e53dfaafd4d7f08a74e76db22af88 by Mark Barolak <mbar@google.com>:

Internal fix

PiperOrigin-RevId: 201043684

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64b53edd6bf1fa48f74e7f5d33f00f80d5089147 by Shaindel Schwartz <shaindel@google.com>:

Remove extra whitespace

PiperOrigin-RevId: 201041989

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0bdd2a0b33657b688e4a04aeba9ebba47e4dc6ca by Shaindel Schwartz <shaindel@google.com>:

Whitespace fix.

PiperOrigin-RevId: 201034413

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3deb0ac296ef1b74c4789e114a8a8bf53253f26b by Shaindel Schwartz <shaindel@google.com>:

Scrub build tags. No functional changes.

PiperOrigin-RevId: 201032927

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da75d0f8b73baa7e8f4e9a092bba546012ed3b71 by Alex Strelnikov <strel@google.com>:

Internal change.

PiperOrigin-RevId: 201026131

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6815d80caa19870d0c441b6b9816c68db41393a5 by Tom Manshreck <shreck@google.com>:

Add documentation for our LTS snapshot branches

PiperOrigin-RevId: 201025191

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64c3b02006f39e6a8127bbabf9ec947fb45b6504 by Greg Falcon <gfalcon@google.com>:

Provide absl::from_chars for double and float types.  This is a forward-compatible implementation of std::from_chars from C++17.

This provides exact "round_to_nearest" conversions, and has some nice properties:

* Works with string_view (it can convert numbers from non-NUL-terminated buffers)
* Never allocates memory
* Faster than the standard library strtod() in our toolchain
* Uses integer math in its calculations, so is unaffected by floating point environment
* Unaffected by C locale

Also change SimpleAtod/SimpleAtoi to use this new API under the hood.

PiperOrigin-RevId: 201003324

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542869258eb100779497c899103dc96aced52749 by Greg Falcon <gfalcon@google.com>:

Internal change

PiperOrigin-RevId: 200999200

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3aba192775c7f80e2cd7f221b0a73537823c54ea by Gennadiy Rozental <rogeeff@google.com>:

Internal change

PiperOrigin-RevId: 200947470

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daf9b9feedd748d5364a4c06165b7cb7604d3e1e by Mark Barolak <mbar@google.com>:

Add an absl:: qualification to a usage of base_internal::SchedulingMode outside of an absl:: namespace.

PiperOrigin-RevId: 200748234

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a8d265290a22d629f3d9bf9f872c204200bfe8c8 by Mark Barolak <mbar@google.com>:

Add a missing namespace closing comment to optional.h.

PiperOrigin-RevId: 200739934

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f05af8ee1c6b864dad2df7c907d424209a3e3202 by Abseil Team <absl-team@google.com>:

Internal change

PiperOrigin-RevId: 200719115
GitOrigin-RevId: f28d30df5769bb832dec3ff36d2fcd2bcdf494a3
Change-Id: Ie4fa601078fd4aa57286372611f1d114fdec82c0

1 files changed, 96 insertions, 0 deletions

diff --git a/absl/strings/internal/charconv_parse.h b/absl/strings/internal/charconv_parse.h
new file mode 100644
index 00000000..7a5c0874
--- /dev/null
+++ b/absl/strings/internal/charconv_parse.h
@@ -0,0 +1,96 @@
+// Copyright 2018 The Abseil Authors.
+//
+// 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
+//
+//      http://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.
+
+#ifndef ABSL_STRINGS_INTERNAL_CHARCONV_PARSE_H_
+#define ABSL_STRINGS_INTERNAL_CHARCONV_PARSE_H_
+
+#include <cstdint>
+
+#include "absl/strings/charconv.h"
+
+namespace absl {
+namespace strings_internal {
+
+// Enum indicating whether a parsed float is a number or special value.
+enum class FloatType { kNumber, kInfinity, kNan };
+
+// The decomposed parts of a parsed `float` or `double`.
+struct ParsedFloat {
+  // Representation of the parsed mantissa, with the decimal point adjusted to
+  // make it an integer.
+  //
+  // During decimal scanning, this contains 19 significant digits worth of
+  // mantissa value.  If digits beyond this point are found, they
+  // are truncated, and if any of these dropped digits are nonzero, then
+  // `mantissa` is inexact, and the full mantissa is stored in [subrange_begin,
+  // subrange_end).
+  //
+  // During hexadecimal scanning, this contains 15 significant hex digits worth
+  // of mantissa value.  Digits beyond this point are sticky -- they are
+  // truncated, but if any dropped digits are nonzero, the low bit of mantissa
+  // will be set.  (This allows for precise rounding, and avoids the need
+  // to store the full mantissa in [subrange_begin, subrange_end).)
+  uint64_t mantissa = 0;
+
+  // Floating point expontent.  This reflects any decimal point adjustments and
+  // any truncated digits from the mantissa.  The absolute value of the parsed
+  // number is represented by mantissa * (base ** exponent), where base==10 for
+  // decimal floats, and base==2 for hexadecimal floats.
+  int exponent = 0;
+
+  // The literal exponent value scanned from the input, or 0 if none was
+  // present.  This does not reflect any adjustments applied to mantissa.
+  int literal_exponent = 0;
+
+  // The type of number scanned.
+  FloatType type = FloatType::kNumber;
+
+  // When non-null, [subrange_begin, subrange_end) marks a range of characters
+  // that require further processing.  The meaning is dependent on float type.
+  // If type == kNumber and this is set, this is a "wide input": the input
+  // mantissa contained more than 19 digits.  The range contains the full
+  // mantissa.  It plus `literal_exponent` need to be examined to find the best
+  // floating point match.
+  // If type == kNan and this is set, the range marks the contents of a
+  // matched parenthesized character region after the NaN.
+  const char* subrange_begin = nullptr;
+  const char* subrange_end = nullptr;
+
+  // One-past-the-end of the successfully parsed region, or nullptr if no
+  // matching pattern was found.
+  const char* end = nullptr;
+};
+
+// Read the floating point number in the provided range, and populate
+// ParsedFloat accordingly.
+//
+// format_flags is a bitmask value specifying what patterns this API will match.
+// `scientific` and `fixed`  are honored per std::from_chars rules
+// ([utility.from.chars], C++17): if exactly one of these bits is set, then an
+// exponent is required, or dislallowed, respectively.
+//
+// Template parameter `base` must be either 10 or 16.  For base 16, a "0x" is
+// *not* consumed.  The `hex` bit from format_flags is ignored by ParseFloat.
+template <int base>
+ParsedFloat ParseFloat(const char* begin, const char* end,
+                       absl::chars_format format_flags);
+
+extern template ParsedFloat ParseFloat<10>(const char* begin, const char* end,
+                                           absl::chars_format format_flags);
+extern template ParsedFloat ParseFloat<16>(const char* begin, const char* end,
+                                           absl::chars_format format_flags);
+
+}  // namespace strings_internal
+}  // namespace absl
+#endif  // ABSL_STRINGS_INTERNAL_CHARCONV_PARSE_H_