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authorGravatar Abseil Team <absl-team@google.com>2018-06-20 06:25:23 -0700
committerGravatar Shaindel Schwartz <shaindel@google.com>2018-06-20 10:15:31 -0400
commit6c7de165d1c82684359ccb630bb5f83263fa5ebc (patch)
treef271bc0005ad42773cc0140100699b8bfbaea124 /absl/strings/internal
parente5be80532b5d998813f9db952d2cc5401b1532df (diff)
Project import generated by Copybara.20180600
GitOrigin-RevId: d89dba27e35462d7457121b978fd79214205e686 Change-Id: I0eae80578a93a580820bc90d42e6b42faf7fde0a
Diffstat (limited to 'absl/strings/internal')
-rw-r--r--absl/strings/internal/bits.h2
-rw-r--r--absl/strings/internal/char_map.h2
-rw-r--r--absl/strings/internal/charconv_bigint.cc359
-rw-r--r--absl/strings/internal/charconv_bigint.h428
-rw-r--r--absl/strings/internal/charconv_bigint_test.cc205
-rw-r--r--absl/strings/internal/charconv_parse.cc498
-rw-r--r--absl/strings/internal/charconv_parse.h98
-rw-r--r--absl/strings/internal/charconv_parse_test.cc357
-rw-r--r--absl/strings/internal/escaping_test_common.h2
-rw-r--r--absl/strings/internal/memutil.cc2
-rw-r--r--absl/strings/internal/memutil.h2
-rw-r--r--absl/strings/internal/numbers_test_common.h2
-rw-r--r--absl/strings/internal/ostringstream.cc2
-rw-r--r--absl/strings/internal/ostringstream.h2
-rw-r--r--absl/strings/internal/resize_uninitialized.h2
-rw-r--r--absl/strings/internal/stl_type_traits.h2
-rw-r--r--absl/strings/internal/str_join_internal.h2
-rw-r--r--absl/strings/internal/str_split_internal.h2
-rw-r--r--absl/strings/internal/utf8.cc2
-rw-r--r--absl/strings/internal/utf8.h2
20 files changed, 1973 insertions, 0 deletions
diff --git a/absl/strings/internal/bits.h b/absl/strings/internal/bits.h
index 901082cc..a7d0ee5b 100644
--- a/absl/strings/internal/bits.h
+++ b/absl/strings/internal/bits.h
@@ -23,6 +23,7 @@
#endif
namespace absl {
+inline namespace lts_2018_06_20 {
namespace strings_internal {
// Returns the number of leading 0 bits in a 64-bit value.
@@ -48,6 +49,7 @@ inline int CountLeadingZeros64(uint64_t n) {
}
} // namespace strings_internal
+} // inline namespace lts_2018_06_20
} // namespace absl
#endif // ABSL_STRINGS_INTERNAL_BITS_H_
diff --git a/absl/strings/internal/char_map.h b/absl/strings/internal/char_map.h
index 8d92963a..e1280b03 100644
--- a/absl/strings/internal/char_map.h
+++ b/absl/strings/internal/char_map.h
@@ -28,6 +28,7 @@
#include "absl/base/port.h"
namespace absl {
+inline namespace lts_2018_06_20 {
namespace strings_internal {
class Charmap {
@@ -149,6 +150,7 @@ constexpr Charmap GraphCharmap() { return PrintCharmap() & ~SpaceCharmap(); }
constexpr Charmap PunctCharmap() { return GraphCharmap() & ~AlnumCharmap(); }
} // namespace strings_internal
+} // inline namespace lts_2018_06_20
} // namespace absl
#endif // ABSL_STRINGS_INTERNAL_CHAR_MAP_H_
diff --git a/absl/strings/internal/charconv_bigint.cc b/absl/strings/internal/charconv_bigint.cc
new file mode 100644
index 00000000..eb2e2976
--- /dev/null
+++ b/absl/strings/internal/charconv_bigint.cc
@@ -0,0 +1,359 @@
+// 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.
+
+#include "absl/strings/internal/charconv_bigint.h"
+
+#include <algorithm>
+#include <cassert>
+#include <string>
+
+namespace absl {
+inline namespace lts_2018_06_20 {
+namespace strings_internal {
+
+namespace {
+
+// Table containing some large powers of 5, for fast computation.
+
+// Constant step size for entries in the kLargePowersOfFive table. Each entry
+// is larger than the previous entry by a factor of 5**kLargePowerOfFiveStep
+// (or 5**27).
+//
+// In other words, the Nth entry in the table is 5**(27*N).
+//
+// 5**27 is the largest power of 5 that fits in 64 bits.
+constexpr int kLargePowerOfFiveStep = 27;
+
+// The largest legal index into the kLargePowersOfFive table.
+//
+// In other words, the largest precomputed power of 5 is 5**(27*20).
+constexpr int kLargestPowerOfFiveIndex = 20;
+
+// Table of powers of (5**27), up to (5**27)**20 == 5**540.
+//
+// Used to generate large powers of 5 while limiting the number of repeated
+// multiplications required.
+//
+// clang-format off
+const uint32_t kLargePowersOfFive[] = {
+// 5**27 (i=1), start=0, end=2
+ 0xfa10079dU, 0x6765c793U,
+// 5**54 (i=2), start=2, end=6
+ 0x97d9f649U, 0x6664242dU, 0x29939b14U, 0x29c30f10U,
+// 5**81 (i=3), start=6, end=12
+ 0xc4f809c5U, 0x7bf3f22aU, 0x67bdae34U, 0xad340517U, 0x369d1b5fU, 0x10de1593U,
+// 5**108 (i=4), start=12, end=20
+ 0x92b260d1U, 0x9efff7c7U, 0x81de0ec6U, 0xaeba5d56U, 0x410664a4U, 0x4f40737aU,
+ 0x20d3846fU, 0x06d00f73U,
+// 5**135 (i=5), start=20, end=30
+ 0xff1b172dU, 0x13a1d71cU, 0xefa07617U, 0x7f682d3dU, 0xff8c90c0U, 0x3f0131e7U,
+ 0x3fdcb9feU, 0x917b0177U, 0x16c407a7U, 0x02c06b9dU,
+// 5**162 (i=6), start=30, end=42
+ 0x960f7199U, 0x056667ecU, 0xe07aefd8U, 0x80f2b9ccU, 0x8273f5e3U, 0xeb9a214aU,
+ 0x40b38005U, 0x0e477ad4U, 0x277d08e6U, 0xfa28b11eU, 0xd3f7d784U, 0x011c835bU,
+// 5**189 (i=7), start=42, end=56
+ 0xf723d9d5U, 0x3282d3f3U, 0xe00857d1U, 0x69659d25U, 0x2cf117cfU, 0x24da6d07U,
+ 0x954d1417U, 0x3e5d8cedU, 0x7a8bb766U, 0xfd785ae6U, 0x645436d2U, 0x40c78b34U,
+ 0x94151217U, 0x0072e9f7U,
+// 5**216 (i=8), start=56, end=72
+ 0x2b416aa1U, 0x7893c5a7U, 0xe37dc6d4U, 0x2bad2beaU, 0xf0fc846cU, 0x7575ae4bU,
+ 0x62587b14U, 0x83b67a34U, 0x02110cdbU, 0xf7992f55U, 0x00deb022U, 0xa4a23becU,
+ 0x8af5c5cdU, 0xb85b654fU, 0x818df38bU, 0x002e69d2U,
+// 5**243 (i=9), start=72, end=90
+ 0x3518cbbdU, 0x20b0c15fU, 0x38756c2fU, 0xfb5dc3ddU, 0x22ad2d94U, 0xbf35a952U,
+ 0xa699192aU, 0x9a613326U, 0xad2a9cedU, 0xd7f48968U, 0xe87dfb54U, 0xc8f05db6U,
+ 0x5ef67531U, 0x31c1ab49U, 0xe202ac9fU, 0x9b2957b5U, 0xa143f6d3U, 0x0012bf07U,
+// 5**270 (i=10), start=90, end=110
+ 0x8b971de9U, 0x21aba2e1U, 0x63944362U, 0x57172336U, 0xd9544225U, 0xfb534166U,
+ 0x08c563eeU, 0x14640ee2U, 0x24e40d31U, 0x02b06537U, 0x03887f14U, 0x0285e533U,
+ 0xb744ef26U, 0x8be3a6c4U, 0x266979b4U, 0x6761ece2U, 0xd9cb39e4U, 0xe67de319U,
+ 0x0d39e796U, 0x00079250U,
+// 5**297 (i=11), start=110, end=132
+ 0x260eb6e5U, 0xf414a796U, 0xee1a7491U, 0xdb9368ebU, 0xf50c105bU, 0x59157750U,
+ 0x9ed2fb5cU, 0xf6e56d8bU, 0xeaee8d23U, 0x0f319f75U, 0x2aa134d6U, 0xac2908e9U,
+ 0xd4413298U, 0x02f02a55U, 0x989d5a7aU, 0x70dde184U, 0xba8040a7U, 0x03200981U,
+ 0xbe03b11cU, 0x3c1c2a18U, 0xd60427a1U, 0x00030ee0U,
+// 5**324 (i=12), start=132, end=156
+ 0xce566d71U, 0xf1c4aa25U, 0x4e93ca53U, 0xa72283d0U, 0x551a73eaU, 0x3d0538e2U,
+ 0x8da4303fU, 0x6a58de60U, 0x0e660221U, 0x49cf61a6U, 0x8d058fc1U, 0xb9d1a14cU,
+ 0x4bab157dU, 0xc85c6932U, 0x518c8b9eU, 0x9b92b8d0U, 0x0d8a0e21U, 0xbd855df9U,
+ 0xb3ea59a1U, 0x8da29289U, 0x4584d506U, 0x3752d80fU, 0xb72569c6U, 0x00013c33U,
+// 5**351 (i=13), start=156, end=182
+ 0x190f354dU, 0x83695cfeU, 0xe5a4d0c7U, 0xb60fb7e8U, 0xee5bbcc4U, 0xb922054cU,
+ 0xbb4f0d85U, 0x48394028U, 0x1d8957dbU, 0x0d7edb14U, 0x4ecc7587U, 0x505e9e02U,
+ 0x4c87f36bU, 0x99e66bd6U, 0x44b9ed35U, 0x753037d4U, 0xe5fe5f27U, 0x2742c203U,
+ 0x13b2ed2bU, 0xdc525d2cU, 0xe6fde59aU, 0x77ffb18fU, 0x13c5752cU, 0x08a84bccU,
+ 0x859a4940U, 0x00007fb6U,
+// 5**378 (i=14), start=182, end=210
+ 0x4f98cb39U, 0xa60edbbcU, 0x83b5872eU, 0xa501acffU, 0x9cc76f78U, 0xbadd4c73U,
+ 0x43e989faU, 0xca7acf80U, 0x2e0c824fU, 0xb19f4ffcU, 0x092fd81cU, 0xe4eb645bU,
+ 0xa1ff84c2U, 0x8a5a83baU, 0xa8a1fae9U, 0x1db43609U, 0xb0fed50bU, 0x0dd7d2bdU,
+ 0x7d7accd8U, 0x91fa640fU, 0x37dcc6c5U, 0x1c417fd5U, 0xe4d462adU, 0xe8a43399U,
+ 0x131bf9a5U, 0x8df54d29U, 0x36547dc1U, 0x00003395U,
+// 5**405 (i=15), start=210, end=240
+ 0x5bd330f5U, 0x77d21967U, 0x1ac481b7U, 0x6be2f7ceU, 0x7f4792a9U, 0xe84c2c52U,
+ 0x84592228U, 0x9dcaf829U, 0xdab44ce1U, 0x3d0c311bU, 0x532e297dU, 0x4704e8b4U,
+ 0x9cdc32beU, 0x41e64d9dU, 0x7717bea1U, 0xa824c00dU, 0x08f50b27U, 0x0f198d77U,
+ 0x49bbfdf0U, 0x025c6c69U, 0xd4e55cd3U, 0xf083602bU, 0xb9f0fecdU, 0xc0864aeaU,
+ 0x9cb98681U, 0xaaf620e9U, 0xacb6df30U, 0x4faafe66U, 0x8af13c3bU, 0x000014d5U,
+// 5**432 (i=16), start=240, end=272
+ 0x682bb941U, 0x89a9f297U, 0xcba75d7bU, 0x404217b1U, 0xb4e519e9U, 0xa1bc162bU,
+ 0xf7f5910aU, 0x98715af5U, 0x2ff53e57U, 0xe3ef118cU, 0x490c4543U, 0xbc9b1734U,
+ 0x2affbe4dU, 0x4cedcb4cU, 0xfb14e99eU, 0x35e34212U, 0xece39c24U, 0x07673ab3U,
+ 0xe73115ddU, 0xd15d38e7U, 0x093eed3bU, 0xf8e7eac5U, 0x78a8cc80U, 0x25227aacU,
+ 0x3f590551U, 0x413da1cbU, 0xdf643a55U, 0xab65ad44U, 0xd70b23d7U, 0xc672cd76U,
+ 0x3364ea62U, 0x0000086aU,
+// 5**459 (i=17), start=272, end=306
+ 0x22f163ddU, 0x23cf07acU, 0xbe2af6c2U, 0xf412f6f6U, 0xc3ff541eU, 0x6eeaf7deU,
+ 0xa47047e0U, 0x408cda92U, 0x0f0eeb08U, 0x56deba9dU, 0xcfc6b090U, 0x8bbbdf04U,
+ 0x3933cdb3U, 0x9e7bb67dU, 0x9f297035U, 0x38946244U, 0xee1d37bbU, 0xde898174U,
+ 0x63f3559dU, 0x705b72fbU, 0x138d27d9U, 0xf8603a78U, 0x735eec44U, 0xe30987d5U,
+ 0xc6d38070U, 0x9cfe548eU, 0x9ff01422U, 0x7c564aa8U, 0x91cc60baU, 0xcbc3565dU,
+ 0x7550a50bU, 0x6909aeadU, 0x13234c45U, 0x00000366U,
+// 5**486 (i=18), start=306, end=342
+ 0x17954989U, 0x3a7d7709U, 0x98042de5U, 0xa9011443U, 0x45e723c2U, 0x269ffd6fU,
+ 0x58852a46U, 0xaaa1042aU, 0x2eee8153U, 0xb2b6c39eU, 0xaf845b65U, 0xf6c365d7U,
+ 0xe4cffb2bU, 0xc840e90cU, 0xabea8abbU, 0x5c58f8d2U, 0x5c19fa3aU, 0x4670910aU,
+ 0x4449f21cU, 0xefa645b3U, 0xcc427decU, 0x083c3d73U, 0x467cb413U, 0x6fe10ae4U,
+ 0x3caffc72U, 0x9f8da55eU, 0x5e5c8ea7U, 0x490594bbU, 0xf0871b0bU, 0xdd89816cU,
+ 0x8e931df8U, 0xe85ce1c9U, 0xcca090a5U, 0x575fa16bU, 0x6b9f106cU, 0x0000015fU,
+// 5**513 (i=19), start=342, end=380
+ 0xee20d805U, 0x57bc3c07U, 0xcdea624eU, 0xd3f0f52dU, 0x9924b4f4U, 0xcf968640U,
+ 0x61d41962U, 0xe87fb464U, 0xeaaf51c7U, 0x564c8b60U, 0xccda4028U, 0x529428bbU,
+ 0x313a1fa8U, 0x96bd0f94U, 0x7a82ebaaU, 0xad99e7e9U, 0xf2668cd4U, 0xbe33a45eU,
+ 0xfd0db669U, 0x87ee369fU, 0xd3ec20edU, 0x9c4d7db7U, 0xdedcf0d8U, 0x7cd2ca64U,
+ 0xe25a6577U, 0x61003fd4U, 0xe56f54ccU, 0x10b7c748U, 0x40526e5eU, 0x7300ae87U,
+ 0x5c439261U, 0x2c0ff469U, 0xbf723f12U, 0xb2379b61U, 0xbf59b4f5U, 0xc91b1c3fU,
+ 0xf0046d27U, 0x0000008dU,
+// 5**540 (i=20), start=380, end=420
+ 0x525c9e11U, 0xf4e0eb41U, 0xebb2895dU, 0x5da512f9U, 0x7d9b29d4U, 0x452f4edcU,
+ 0x0b90bc37U, 0x341777cbU, 0x63d269afU, 0x1da77929U, 0x0a5c1826U, 0x77991898U,
+ 0x5aeddf86U, 0xf853a877U, 0x538c31ccU, 0xe84896daU, 0xb7a0010bU, 0x17ef4de5U,
+ 0xa52a2adeU, 0x029fd81cU, 0x987ce701U, 0x27fefd77U, 0xdb46c66fU, 0x5d301900U,
+ 0x496998c0U, 0xbb6598b9U, 0x5eebb607U, 0xe547354aU, 0xdf4a2f7eU, 0xf06c4955U,
+ 0x96242ffaU, 0x1775fb27U, 0xbecc58ceU, 0xebf2a53bU, 0x3eaad82aU, 0xf41137baU,
+ 0x573e6fbaU, 0xfb4866b8U, 0x54002148U, 0x00000039U,
+};
+// clang-format on
+
+// Returns a pointer to the big integer data for (5**27)**i. i must be
+// between 1 and 20, inclusive.
+const uint32_t* LargePowerOfFiveData(int i) {
+ return kLargePowersOfFive + i * (i - 1);
+}
+
+// Returns the size of the big integer data for (5**27)**i, in words. i must be
+// between 1 and 20, inclusive.
+int LargePowerOfFiveSize(int i) { return 2 * i; }
+} // namespace
+
+const uint32_t kFiveToNth[14] = {
+ 1, 5, 25, 125, 625, 3125, 15625,
+ 78125, 390625, 1953125, 9765625, 48828125, 244140625, 1220703125,
+};
+
+const uint32_t kTenToNth[10] = {
+ 1, 10, 100, 1000, 10000, 100000, 1000000, 10000000, 100000000, 1000000000,
+};
+
+template <int max_words>
+int BigUnsigned<max_words>::ReadFloatMantissa(const ParsedFloat& fp,
+ int significant_digits) {
+ SetToZero();
+ assert(fp.type == FloatType::kNumber);
+
+ if (fp.subrange_begin == nullptr) {
+ // We already exactly parsed the mantissa, so no more work is necessary.
+ words_[0] = fp.mantissa & 0xffffffffu;
+ words_[1] = fp.mantissa >> 32;
+ if (words_[1]) {
+ size_ = 2;
+ } else if (words_[0]) {
+ size_ = 1;
+ }
+ return fp.exponent;
+ }
+ int exponent_adjust =
+ ReadDigits(fp.subrange_begin, fp.subrange_end, significant_digits);
+ return fp.literal_exponent + exponent_adjust;
+}
+
+template <int max_words>
+int BigUnsigned<max_words>::ReadDigits(const char* begin, const char* end,
+ int significant_digits) {
+ assert(significant_digits <= Digits10() + 1);
+ SetToZero();
+
+ bool after_decimal_point = false;
+ // Discard any leading zeroes before the decimal point
+ while (begin < end && *begin == '0') {
+ ++begin;
+ }
+ int dropped_digits = 0;
+ // Discard any trailing zeroes. These may or may not be after the decimal
+ // point.
+ while (begin < end && *std::prev(end) == '0') {
+ --end;
+ ++dropped_digits;
+ }
+ if (begin < end && *std::prev(end) == '.') {
+ // If the std::string ends in '.', either before or after dropping zeroes, then
+ // drop the decimal point and look for more digits to drop.
+ dropped_digits = 0;
+ --end;
+ while (begin < end && *std::prev(end) == '0') {
+ --end;
+ ++dropped_digits;
+ }
+ } else if (dropped_digits) {
+ // We dropped digits, and aren't sure if they're before or after the decimal
+ // point. Figure that out now.
+ const char* dp = std::find(begin, end, '.');
+ if (dp != end) {
+ // The dropped trailing digits were after the decimal point, so don't
+ // count them.
+ dropped_digits = 0;
+ }
+ }
+ // Any non-fraction digits we dropped need to be accounted for in our exponent
+ // adjustment.
+ int exponent_adjust = dropped_digits;
+
+ uint32_t queued = 0;
+ int digits_queued = 0;
+ for (; begin != end && significant_digits > 0; ++begin) {
+ if (*begin == '.') {
+ after_decimal_point = true;
+ continue;
+ }
+ if (after_decimal_point) {
+ // For each fractional digit we emit in our parsed integer, adjust our
+ // decimal exponent to compensate.
+ --exponent_adjust;
+ }
+ int digit = (*begin - '0');
+ --significant_digits;
+ if (significant_digits == 0 && std::next(begin) != end &&
+ (digit == 0 || digit == 5)) {
+ // If this is the very last significant digit, but insignificant digits
+ // remain, we know that the last of those remaining significant digits is
+ // nonzero. (If it wasn't, we would have stripped it before we got here.)
+ // So if this final digit is a 0 or 5, adjust it upward by 1.
+ //
+ // This adjustment is what allows incredibly large mantissas ending in
+ // 500000...000000000001 to correctly round up, rather than to nearest.
+ ++digit;
+ }
+ queued = 10 * queued + digit;
+ ++digits_queued;
+ if (digits_queued == kMaxSmallPowerOfTen) {
+ MultiplyBy(kTenToNth[kMaxSmallPowerOfTen]);
+ AddWithCarry(0, queued);
+ queued = digits_queued = 0;
+ }
+ }
+ // Encode any remaining digits.
+ if (digits_queued) {
+ MultiplyBy(kTenToNth[digits_queued]);
+ AddWithCarry(0, queued);
+ }
+
+ // If any insignificant digits remain, we will drop them. But if we have not
+ // yet read the decimal point, then we have to adjust the exponent to account
+ // for the dropped digits.
+ if (begin < end && !after_decimal_point) {
+ // This call to std::find will result in a pointer either to the decimal
+ // point, or to the end of our buffer if there was none.
+ //
+ // Either way, [begin, decimal_point) will contain the set of dropped digits
+ // that require an exponent adjustment.
+ const char* decimal_point = std::find(begin, end, '.');
+ exponent_adjust += (decimal_point - begin);
+ }
+ return exponent_adjust;
+}
+
+template <int max_words>
+/* static */ BigUnsigned<max_words> BigUnsigned<max_words>::FiveToTheNth(
+ int n) {
+ BigUnsigned answer(1u);
+
+ // Seed from the table of large powers, if possible.
+ bool first_pass = true;
+ while (n >= kLargePowerOfFiveStep) {
+ int big_power =
+ std::min(n / kLargePowerOfFiveStep, kLargestPowerOfFiveIndex);
+ if (first_pass) {
+ // just copy, rather than multiplying by 1
+ std::copy(
+ LargePowerOfFiveData(big_power),
+ LargePowerOfFiveData(big_power) + LargePowerOfFiveSize(big_power),
+ answer.words_);
+ answer.size_ = LargePowerOfFiveSize(big_power);
+ first_pass = false;
+ } else {
+ answer.MultiplyBy(LargePowerOfFiveSize(big_power),
+ LargePowerOfFiveData(big_power));
+ }
+ n -= kLargePowerOfFiveStep * big_power;
+ }
+ answer.MultiplyByFiveToTheNth(n);
+ return answer;
+}
+
+template <int max_words>
+void BigUnsigned<max_words>::MultiplyStep(int original_size,
+ const uint32_t* other_words,
+ int other_size, int step) {
+ int this_i = std::min(original_size - 1, step);
+ int other_i = step - this_i;
+
+ uint64_t this_word = 0;
+ uint64_t carry = 0;
+ for (; this_i >= 0 && other_i < other_size; --this_i, ++other_i) {
+ uint64_t product = words_[this_i];
+ product *= other_words[other_i];
+ this_word += product;
+ carry += (this_word >> 32);
+ this_word &= 0xffffffff;
+ }
+ AddWithCarry(step + 1, carry);
+ words_[step] = this_word & 0xffffffff;
+ if (this_word > 0 && size_ <= step) {
+ size_ = step + 1;
+ }
+}
+
+template <int max_words>
+std::string BigUnsigned<max_words>::ToString() const {
+ BigUnsigned<max_words> copy = *this;
+ std::string result;
+ // Build result in reverse order
+ while (copy.size() > 0) {
+ int next_digit = copy.DivMod<10>();
+ result.push_back('0' + next_digit);
+ }
+ if (result.empty()) {
+ result.push_back('0');
+ }
+ std::reverse(result.begin(), result.end());
+ return result;
+}
+
+template class BigUnsigned<4>;
+template class BigUnsigned<84>;
+
+} // namespace strings_internal
+} // inline namespace lts_2018_06_20
+} // namespace absl
diff --git a/absl/strings/internal/charconv_bigint.h b/absl/strings/internal/charconv_bigint.h
new file mode 100644
index 00000000..9827b56e
--- /dev/null
+++ b/absl/strings/internal/charconv_bigint.h
@@ -0,0 +1,428 @@
+// 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_BIGINT_H_
+#define ABSL_STRINGS_INTERNAL_CHARCONV_BIGINT_H_
+
+#include <algorithm>
+#include <cstdint>
+#include <iostream>
+#include <string>
+
+#include "absl/strings/ascii.h"
+#include "absl/strings/internal/charconv_parse.h"
+#include "absl/strings/string_view.h"
+
+namespace absl {
+inline namespace lts_2018_06_20 {
+namespace strings_internal {
+
+// The largest power that 5 that can be raised to, and still fit in a uint32_t.
+constexpr int kMaxSmallPowerOfFive = 13;
+// The largest power that 10 that can be raised to, and still fit in a uint32_t.
+constexpr int kMaxSmallPowerOfTen = 9;
+
+extern const uint32_t kFiveToNth[kMaxSmallPowerOfFive + 1];
+extern const uint32_t kTenToNth[kMaxSmallPowerOfTen + 1];
+
+// Large, fixed-width unsigned integer.
+//
+// Exact rounding for decimal-to-binary floating point conversion requires very
+// large integer math, but a design goal of absl::from_chars is to avoid
+// allocating memory. The integer precision needed for decimal-to-binary
+// conversions is large but bounded, so a huge fixed-width integer class
+// suffices.
+//
+// This is an intentionally limited big integer class. Only needed operations
+// are implemented. All storage lives in an array data member, and all
+// arithmetic is done in-place, to avoid requiring separate storage for operand
+// and result.
+//
+// This is an internal class. Some methods live in the .cc file, and are
+// instantiated only for the values of max_words we need.
+template <int max_words>
+class BigUnsigned {
+ public:
+ static_assert(max_words == 4 || max_words == 84,
+ "unsupported max_words value");
+
+ BigUnsigned() : size_(0), words_{} {}
+ explicit BigUnsigned(uint32_t v) : size_(v > 0 ? 1 : 0), words_{v} {}
+ explicit BigUnsigned(uint64_t v)
+ : size_(0),
+ words_{static_cast<uint32_t>(v & 0xffffffff),
+ static_cast<uint32_t>(v >> 32)} {
+ if (words_[1]) {
+ size_ = 2;
+ } else if (words_[0]) {
+ size_ = 1;
+ }
+ }
+
+ // Constructs a BigUnsigned from the given string_view containing a decimal
+ // value. If the input std::string is not a decimal integer, constructs a 0
+ // instead.
+ explicit BigUnsigned(absl::string_view sv) : size_(0), words_{} {
+ // Check for valid input, returning a 0 otherwise. This is reasonable
+ // behavior only because this constructor is for unit tests.
+ if (std::find_if_not(sv.begin(), sv.end(), ascii_isdigit) != sv.end() ||
+ sv.empty()) {
+ return;
+ }
+ int exponent_adjust =
+ ReadDigits(sv.data(), sv.data() + sv.size(), Digits10() + 1);
+ if (exponent_adjust > 0) {
+ MultiplyByTenToTheNth(exponent_adjust);
+ }
+ }
+
+ // Loads the mantissa value of a previously-parsed float.
+ //
+ // Returns the associated decimal exponent. The value of the parsed float is
+ // exactly *this * 10**exponent.
+ int ReadFloatMantissa(const ParsedFloat& fp, int significant_digits);
+
+ // Returns the number of decimal digits of precision this type provides. All
+ // numbers with this many decimal digits or fewer are representable by this
+ // type.
+ //
+ // Analagous to std::numeric_limits<BigUnsigned>::digits10.
+ static constexpr int Digits10() {
+ // 9975007/1035508 is very slightly less than log10(2**32).
+ return static_cast<uint64_t>(max_words) * 9975007 / 1035508;
+ }
+
+ // Shifts left by the given number of bits.
+ void ShiftLeft(int count) {
+ if (count > 0) {
+ const int word_shift = count / 32;
+ if (word_shift >= max_words) {
+ SetToZero();
+ return;
+ }
+ size_ = std::min(size_ + word_shift, max_words);
+ count %= 32;
+ if (count == 0) {
+ std::copy_backward(words_, words_ + size_ - word_shift, words_ + size_);
+ } else {
+ for (int i = std::min(size_, max_words - 1); i > word_shift; --i) {
+ words_[i] = (words_[i - word_shift] << count) |
+ (words_[i - word_shift - 1] >> (32 - count));
+ }
+ words_[word_shift] = words_[0] << count;
+ // Grow size_ if necessary.
+ if (size_ < max_words && words_[size_]) {
+ ++size_;
+ }
+ }
+ std::fill(words_, words_ + word_shift, 0u);
+ }
+ }
+
+
+ // Multiplies by v in-place.
+ void MultiplyBy(uint32_t v) {
+ if (size_ == 0 || v == 1) {
+ return;
+ }
+ if (v == 0) {
+ SetToZero();
+ return;
+ }
+ const uint64_t factor = v;
+ uint64_t window = 0;
+ for (int i = 0; i < size_; ++i) {
+ window += factor * words_[i];
+ words_[i] = window & 0xffffffff;
+ window >>= 32;
+ }
+ // If carry bits remain and there's space for them, grow size_.
+ if (window && size_ < max_words) {
+ words_[size_] = window & 0xffffffff;
+ ++size_;
+ }
+ }
+
+ void MultiplyBy(uint64_t v) {
+ uint32_t words[2];
+ words[0] = static_cast<uint32_t>(v);
+ words[1] = static_cast<uint32_t>(v >> 32);
+ if (words[1] == 0) {
+ MultiplyBy(words[0]);
+ } else {
+ MultiplyBy(2, words);
+ }
+ }
+
+ // Multiplies in place by 5 to the power of n. n must be non-negative.
+ void MultiplyByFiveToTheNth(int n) {
+ while (n >= kMaxSmallPowerOfFive) {
+ MultiplyBy(kFiveToNth[kMaxSmallPowerOfFive]);
+ n -= kMaxSmallPowerOfFive;
+ }
+ if (n > 0) {
+ MultiplyBy(kFiveToNth[n]);
+ }
+ }
+
+ // Multiplies in place by 10 to the power of n. n must be non-negative.
+ void MultiplyByTenToTheNth(int n) {
+ if (n > kMaxSmallPowerOfTen) {
+ // For large n, raise to a power of 5, then shift left by the same amount.
+ // (10**n == 5**n * 2**n.) This requires fewer multiplications overall.
+ MultiplyByFiveToTheNth(n);
+ ShiftLeft(n);
+ } else if (n > 0) {
+ // We can do this more quickly for very small N by using a single
+ // multiplication.
+ MultiplyBy(kTenToNth[n]);
+ }
+ }
+
+ // Returns the value of 5**n, for non-negative n. This implementation uses
+ // a lookup table, and is faster then seeding a BigUnsigned with 1 and calling
+ // MultiplyByFiveToTheNth().
+ static BigUnsigned FiveToTheNth(int n);
+
+ // Multiplies by another BigUnsigned, in-place.
+ template <int M>
+ void MultiplyBy(const BigUnsigned<M>& other) {
+ MultiplyBy(other.size(), other.words());
+ }
+
+ void SetToZero() {
+ std::fill(words_, words_ + size_, 0u);
+ size_ = 0;
+ }
+
+ // Returns the value of the nth word of this BigUnsigned. This is
+ // range-checked, and returns 0 on out-of-bounds accesses.
+ uint32_t GetWord(int index) const {
+ if (index < 0 || index >= size_) {
+ return 0;
+ }
+ return words_[index];
+ }
+
+ // Returns this integer as a decimal std::string. This is not used in the decimal-
+ // to-binary conversion; it is intended to aid in testing.
+ std::string ToString() const;
+
+ int size() const { return size_; }
+ const uint32_t* words() const { return words_; }
+
+ private:
+ // Reads the number between [begin, end), possibly containing a decimal point,
+ // into this BigUnsigned.
+ //
+ // Callers are required to ensure [begin, end) contains a valid number, with
+ // one or more decimal digits and at most one decimal point. This routine
+ // will behave unpredictably if these preconditions are not met.
+ //
+ // Only the first `significant_digits` digits are read. Digits beyond this
+ // limit are "sticky": If the final significant digit is 0 or 5, and if any
+ // dropped digit is nonzero, then that final significant digit is adjusted up
+ // to 1 or 6. This adjustment allows for precise rounding.
+ //
+ // Returns `exponent_adjustment`, a power-of-ten exponent adjustment to
+ // account for the decimal point and for dropped significant digits. After
+ // this function returns,
+ // actual_value_of_parsed_string ~= *this * 10**exponent_adjustment.
+ int ReadDigits(const char* begin, const char* end, int significant_digits);
+
+ // Performs a step of big integer multiplication. This computes the full
+ // (64-bit-wide) values that should be added at the given index (step), and
+ // adds to that location in-place.
+ //
+ // Because our math all occurs in place, we must multiply starting from the
+ // highest word working downward. (This is a bit more expensive due to the
+ // extra carries involved.)
+ //
+ // This must be called in steps, for each word to be calculated, starting from
+ // the high end and working down to 0. The first value of `step` should be
+ // `std::min(original_size + other.size_ - 2, max_words - 1)`.
+ // The reason for this expression is that multiplying the i'th word from one
+ // multiplicand and the j'th word of another multiplicand creates a
+ // two-word-wide value to be stored at the (i+j)'th element. The highest
+ // word indices we will access are `original_size - 1` from this object, and
+ // `other.size_ - 1` from our operand. Therefore,
+ // `original_size + other.size_ - 2` is the first step we should calculate,
+ // but limited on an upper bound by max_words.
+
+ // Working from high-to-low ensures that we do not overwrite the portions of
+ // the initial value of *this which are still needed for later steps.
+ //
+ // Once called with step == 0, *this contains the result of the
+ // multiplication.
+ //
+ // `original_size` is the size_ of *this before the first call to
+ // MultiplyStep(). `other_words` and `other_size` are the contents of our
+ // operand. `step` is the step to perform, as described above.
+ void MultiplyStep(int original_size, const uint32_t* other_words,
+ int other_size, int step);
+
+ void MultiplyBy(int other_size, const uint32_t* other_words) {
+ const int original_size = size_;
+ const int first_step =
+ std::min(original_size + other_size - 2, max_words - 1);
+ for (int step = first_step; step >= 0; --step) {
+ MultiplyStep(original_size, other_words, other_size, step);
+ }
+ }
+
+ // Adds a 32-bit value to the index'th word, with carry.
+ void AddWithCarry(int index, uint32_t value) {
+ if (value) {
+ while (index < max_words && value > 0) {
+ words_[index] += value;
+ // carry if we overflowed in this word:
+ if (value > words_[index]) {
+ value = 1;
+ ++index;
+ } else {
+ value = 0;
+ }
+ }
+ size_ = std::min(max_words, std::max(index + 1, size_));
+ }
+ }
+
+ void AddWithCarry(int index, uint64_t value) {
+ if (value && index < max_words) {
+ uint32_t high = value >> 32;
+ uint32_t low = value & 0xffffffff;
+ words_[index] += low;
+ if (words_[index] < low) {
+ ++high;
+ if (high == 0) {
+ // Carry from the low word caused our high word to overflow.
+ // Short circuit here to do the right thing.
+ AddWithCarry(index + 2, static_cast<uint32_t>(1));
+ return;
+ }
+ }
+ if (high > 0) {
+ AddWithCarry(index + 1, high);
+ } else {
+ // Normally 32-bit AddWithCarry() sets size_, but since we don't call
+ // it when `high` is 0, do it ourselves here.
+ size_ = std::min(max_words, std::max(index + 1, size_));
+ }
+ }
+ }
+
+ // Divide this in place by a constant divisor. Returns the remainder of the
+ // division.
+ template <uint32_t divisor>
+ uint32_t DivMod() {
+ uint64_t accumulator = 0;
+ for (int i = size_ - 1; i >= 0; --i) {
+ accumulator <<= 32;
+ accumulator += words_[i];
+ // accumulator / divisor will never overflow an int32_t in this loop
+ words_[i] = static_cast<uint32_t>(accumulator / divisor);
+ accumulator = accumulator % divisor;
+ }
+ while (size_ > 0 && words_[size_ - 1] == 0) {
+ --size_;
+ }
+ return static_cast<uint32_t>(accumulator);
+ }
+
+ // The number of elements in words_ that may carry significant values.
+ // All elements beyond this point are 0.
+ //
+ // When size_ is 0, this BigUnsigned stores the value 0.
+ // When size_ is nonzero, is *not* guaranteed that words_[size_ - 1] is
+ // nonzero. This can occur due to overflow truncation.
+ // In particular, x.size_ != y.size_ does *not* imply x != y.
+ int size_;
+ uint32_t words_[max_words];
+};
+
+// Compares two big integer instances.
+//
+// Returns -1 if lhs < rhs, 0 if lhs == rhs, and 1 if lhs > rhs.
+template <int N, int M>
+int Compare(const BigUnsigned<N>& lhs, const BigUnsigned<M>& rhs) {
+ int limit = std::max(lhs.size(), rhs.size());
+ for (int i = limit - 1; i >= 0; --i) {
+ const uint32_t lhs_word = lhs.GetWord(i);
+ const uint32_t rhs_word = rhs.GetWord(i);
+ if (lhs_word < rhs_word) {
+ return -1;
+ } else if (lhs_word > rhs_word) {
+ return 1;
+ }
+ }
+ return 0;
+}
+
+template <int N, int M>
+bool operator==(const BigUnsigned<N>& lhs, const BigUnsigned<M>& rhs) {
+ int limit = std::max(lhs.size(), rhs.size());
+ for (int i = 0; i < limit; ++i) {
+ if (lhs.GetWord(i) != rhs.GetWord(i)) {
+ return false;
+ }
+ }
+ return true;
+}
+
+template <int N, int M>
+bool operator!=(const BigUnsigned<N>& lhs, const BigUnsigned<M>& rhs) {
+ return !(lhs == rhs);
+}
+
+template <int N, int M>
+bool operator<(const BigUnsigned<N>& lhs, const BigUnsigned<M>& rhs) {
+ return Compare(lhs, rhs) == -1;
+}
+
+template <int N, int M>
+bool operator>(const BigUnsigned<N>& lhs, const BigUnsigned<M>& rhs) {
+ return rhs < lhs;
+}
+template <int N, int M>
+bool operator<=(const BigUnsigned<N>& lhs, const BigUnsigned<M>& rhs) {
+ return !(rhs < lhs);
+}
+template <int N, int M>
+bool operator>=(const BigUnsigned<N>& lhs, const BigUnsigned<M>& rhs) {
+ return !(lhs < rhs);
+}
+
+// Output operator for BigUnsigned, for testing purposes only.
+template <int N>
+std::ostream& operator<<(std::ostream& os, const BigUnsigned<N>& num) {
+ return os << num.ToString();
+}
+
+// Explicit instantiation declarations for the sizes of BigUnsigned that we
+// are using.
+//
+// For now, the choices of 4 and 84 are arbitrary; 4 is a small value that is
+// still bigger than an int128, and 84 is a large value we will want to use
+// in the from_chars implementation.
+//
+// Comments justifying the use of 84 belong in the from_chars implementation,
+// and will be added in a follow-up CL.
+extern template class BigUnsigned<4>;
+extern template class BigUnsigned<84>;
+
+} // namespace strings_internal
+} // inline namespace lts_2018_06_20
+} // namespace absl
+
+#endif // ABSL_STRINGS_INTERNAL_CHARCONV_BIGINT_H_
diff --git a/absl/strings/internal/charconv_bigint_test.cc b/absl/strings/internal/charconv_bigint_test.cc
new file mode 100644
index 00000000..118b0dcb
--- /dev/null
+++ b/absl/strings/internal/charconv_bigint_test.cc
@@ -0,0 +1,205 @@
+// 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.
+
+#include "absl/strings/internal/charconv_bigint.h"
+
+#include <string>
+
+#include "gtest/gtest.h"
+
+namespace absl {
+inline namespace lts_2018_06_20 {
+namespace strings_internal {
+
+TEST(BigUnsigned, ShiftLeft) {
+ {
+ // Check that 3 * 2**100 is calculated correctly
+ BigUnsigned<4> num(3u);
+ num.ShiftLeft(100);
+ EXPECT_EQ(num, BigUnsigned<4>("3802951800684688204490109616128"));
+ }
+ {
+ // Test that overflow is truncated properly.
+ // 15 is 4 bits long, and BigUnsigned<4> is a 128-bit bigint.
+ // Shifting left by 125 bits should truncate off the high bit, so that
+ // 15 << 125 == 7 << 125
+ // after truncation.
+ BigUnsigned<4> a(15u);
+ BigUnsigned<4> b(7u);
+ BigUnsigned<4> c(3u);
+ a.ShiftLeft(125);
+ b.ShiftLeft(125);
+ c.ShiftLeft(125);
+ EXPECT_EQ(a, b);
+ EXPECT_NE(a, c);
+ }
+ {
+ // Same test, larger bigint:
+ BigUnsigned<84> a(15u);
+ BigUnsigned<84> b(7u);
+ BigUnsigned<84> c(3u);
+ a.ShiftLeft(84 * 32 - 3);
+ b.ShiftLeft(84 * 32 - 3);
+ c.ShiftLeft(84 * 32 - 3);
+ EXPECT_EQ(a, b);
+ EXPECT_NE(a, c);
+ }
+ {
+ // Check that incrementally shifting has the same result as doing it all at
+ // once (attempting to capture corner cases.)
+ const std::string seed = "1234567890123456789012345678901234567890";
+ BigUnsigned<84> a(seed);
+ for (int i = 1; i <= 84 * 32; ++i) {
+ a.ShiftLeft(1);
+ BigUnsigned<84> b(seed);
+ b.ShiftLeft(i);
+ EXPECT_EQ(a, b);
+ }
+ // And we should have fully rotated all bits off by now:
+ EXPECT_EQ(a, BigUnsigned<84>(0u));
+ }
+}
+
+TEST(BigUnsigned, MultiplyByUint32) {
+ const BigUnsigned<84> factorial_100(
+ "933262154439441526816992388562667004907159682643816214685929638952175999"
+ "932299156089414639761565182862536979208272237582511852109168640000000000"
+ "00000000000000");
+ BigUnsigned<84> a(1u);
+ for (uint32_t i = 1; i <= 100; ++i) {
+ a.MultiplyBy(i);
+ }
+ EXPECT_EQ(a, BigUnsigned<84>(factorial_100));
+}
+
+TEST(BigUnsigned, MultiplyByBigUnsigned) {
+ {
+ // Put the terms of factorial_200 into two bigints, and multiply them
+ // together.
+ const BigUnsigned<84> factorial_200(
+ "7886578673647905035523632139321850622951359776871732632947425332443594"
+ "4996340334292030428401198462390417721213891963883025764279024263710506"
+ "1926624952829931113462857270763317237396988943922445621451664240254033"
+ "2918641312274282948532775242424075739032403212574055795686602260319041"
+ "7032406235170085879617892222278962370389737472000000000000000000000000"
+ "0000000000000000000000000");
+ BigUnsigned<84> evens(1u);
+ BigUnsigned<84> odds(1u);
+ for (uint32_t i = 1; i < 200; i += 2) {
+ odds.MultiplyBy(i);
+ evens.MultiplyBy(i + 1);
+ }
+ evens.MultiplyBy(odds);
+ EXPECT_EQ(evens, factorial_200);
+ }
+ {
+ // Multiply various powers of 10 together.
+ for (int a = 0 ; a < 700; a += 25) {
+ SCOPED_TRACE(a);
+ BigUnsigned<84> a_value("3" + std::string(a, '0'));
+ for (int b = 0; b < (700 - a); b += 25) {
+ SCOPED_TRACE(b);
+ BigUnsigned<84> b_value("2" + std::string(b, '0'));
+ BigUnsigned<84> expected_product("6" + std::string(a + b, '0'));
+ b_value.MultiplyBy(a_value);
+ EXPECT_EQ(b_value, expected_product);
+ }
+ }
+ }
+}
+
+TEST(BigUnsigned, MultiplyByOverflow) {
+ {
+ // Check that multiplcation overflow predictably truncates.
+
+ // A big int with all bits on.
+ BigUnsigned<4> all_bits_on("340282366920938463463374607431768211455");
+ // Modulo 2**128, this is equal to -1. Therefore the square of this,
+ // modulo 2**128, should be 1.
+ all_bits_on.MultiplyBy(all_bits_on);
+ EXPECT_EQ(all_bits_on, BigUnsigned<4>(1u));
+ }
+ {
+ // Try multiplying a large bigint by 2**50, and compare the result to
+ // shifting.
+ BigUnsigned<4> value_1("12345678901234567890123456789012345678");
+ BigUnsigned<4> value_2("12345678901234567890123456789012345678");
+ BigUnsigned<4> two_to_fiftieth(1u);
+ two_to_fiftieth.ShiftLeft(50);
+
+ value_1.ShiftLeft(50);
+ value_2.MultiplyBy(two_to_fiftieth);
+ EXPECT_EQ(value_1, value_2);
+ }
+}
+
+TEST(BigUnsigned, FiveToTheNth) {
+ {
+ // Sanity check that MultiplyByFiveToTheNth gives consistent answers, up to
+ // and including overflow.
+ for (int i = 0; i < 1160; ++i) {
+ SCOPED_TRACE(i);
+ BigUnsigned<84> value_1(123u);
+ BigUnsigned<84> value_2(123u);
+ value_1.MultiplyByFiveToTheNth(i);
+ for (int j = 0; j < i; j++) {
+ value_2.MultiplyBy(5u);
+ }
+ EXPECT_EQ(value_1, value_2);
+ }
+ }
+ {
+ // Check that the faster, table-lookup-based static method returns the same
+ // result that multiplying in-place would return, up to and including
+ // overflow.
+ for (int i = 0; i < 1160; ++i) {
+ SCOPED_TRACE(i);
+ BigUnsigned<84> value_1(1u);
+ value_1.MultiplyByFiveToTheNth(i);
+ BigUnsigned<84> value_2 = BigUnsigned<84>::FiveToTheNth(i);
+ EXPECT_EQ(value_1, value_2);
+ }
+ }
+}
+
+TEST(BigUnsigned, TenToTheNth) {
+ {
+ // Sanity check MultiplyByTenToTheNth.
+ for (int i = 0; i < 800; ++i) {
+ SCOPED_TRACE(i);
+ BigUnsigned<84> value_1(123u);
+ BigUnsigned<84> value_2(123u);
+ value_1.MultiplyByTenToTheNth(i);
+ for (int j = 0; j < i; j++) {
+ value_2.MultiplyBy(10u);
+ }
+ EXPECT_EQ(value_1, value_2);
+ }
+ }
+ {
+ // Alternate testing approach, taking advantage of the decimal parser.
+ for (int i = 0; i < 200; ++i) {
+ SCOPED_TRACE(i);
+ BigUnsigned<84> value_1(135u);
+ value_1.MultiplyByTenToTheNth(i);
+ BigUnsigned<84> value_2("135" + std::string(i, '0'));
+ EXPECT_EQ(value_1, value_2);
+ }
+ }
+}
+
+
+} // namespace strings_internal
+} // inline namespace lts_2018_06_20
+} // namespace absl
diff --git a/absl/strings/internal/charconv_parse.cc b/absl/strings/internal/charconv_parse.cc
new file mode 100644
index 00000000..37d75635
--- /dev/null
+++ b/absl/strings/internal/charconv_parse.cc
@@ -0,0 +1,498 @@
+// 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.
+
+#include "absl/strings/internal/charconv_parse.h"
+#include "absl/strings/charconv.h"
+
+#include <cassert>
+#include <cstdint>
+#include <limits>
+
+#include "absl/strings/internal/memutil.h"
+
+namespace absl {
+inline namespace lts_2018_06_20 {
+namespace {
+
+// ParseFloat<10> will read the first 19 significant digits of the mantissa.
+// This number was chosen for multiple reasons.
+//
+// (a) First, for whatever integer type we choose to represent the mantissa, we
+// want to choose the largest possible number of decimal digits for that integer
+// type. We are using uint64_t, which can express any 19-digit unsigned
+// integer.
+//
+// (b) Second, we need to parse enough digits that the binary value of any
+// mantissa we capture has more bits of resolution than the mantissa
+// representation in the target float. Our algorithm requires at least 3 bits
+// of headway, but 19 decimal digits give a little more than that.
+//
+// The following static assertions verify the above comments:
+constexpr int kDecimalMantissaDigitsMax = 19;
+
+static_assert(std::numeric_limits<uint64_t>::digits10 ==
+ kDecimalMantissaDigitsMax,
+ "(a) above");
+
+// IEEE doubles, which we assume in Abseil, have 53 binary bits of mantissa.
+static_assert(std::numeric_limits<double>::is_iec559, "IEEE double assumed");
+static_assert(std::numeric_limits<double>::radix == 2, "IEEE double fact");
+static_assert(std::numeric_limits<double>::digits == 53, "IEEE double fact");
+
+// The lowest valued 19-digit decimal mantissa we can read still contains
+// sufficient information to reconstruct a binary mantissa.
+static_assert(1000000000000000000u > (uint64_t(1) << (53 + 3)), "(b) above");
+
+// ParseFloat<16> will read the first 15 significant digits of the mantissa.
+//
+// Because a base-16-to-base-2 conversion can be done exactly, we do not need
+// to maximize the number of scanned hex digits to improve our conversion. What
+// is required is to scan two more bits than the mantissa can represent, so that
+// we always round correctly.
+//
+// (One extra bit does not suffice to perform correct rounding, since a number
+// exactly halfway between two representable floats has unique rounding rules,
+// so we need to differentiate between a "halfway between" number and a "closer
+// to the larger value" number.)
+constexpr int kHexadecimalMantissaDigitsMax = 15;
+
+// The minimum number of significant bits that will be read from
+// kHexadecimalMantissaDigitsMax hex digits. We must subtract by three, since
+// the most significant digit can be a "1", which only contributes a single
+// significant bit.
+constexpr int kGuaranteedHexadecimalMantissaBitPrecision =
+ 4 * kHexadecimalMantissaDigitsMax - 3;
+
+static_assert(kGuaranteedHexadecimalMantissaBitPrecision >
+ std::numeric_limits<double>::digits + 2,
+ "kHexadecimalMantissaDigitsMax too small");
+
+// We also impose a limit on the number of significant digits we will read from
+// an exponent, to avoid having to deal with integer overflow. We use 9 for
+// this purpose.
+//
+// If we read a 9 digit exponent, the end result of the conversion will
+// necessarily be infinity or zero, depending on the sign of the exponent.
+// Therefore we can just drop extra digits on the floor without any extra
+// logic.
+constexpr int kDecimalExponentDigitsMax = 9;
+static_assert(std::numeric_limits<int>::digits10 >= kDecimalExponentDigitsMax,
+ "int type too small");
+
+// To avoid incredibly large inputs causing integer overflow for our exponent,
+// we impose an arbitrary but very large limit on the number of significant
+// digits we will accept. The implementation refuses to match a std::string with
+// more consecutive significant mantissa digits than this.
+constexpr int kDecimalDigitLimit = 50000000;
+
+// Corresponding limit for hexadecimal digit inputs. This is one fourth the
+// amount of kDecimalDigitLimit, since each dropped hexadecimal digit requires
+// a binary exponent adjustment of 4.
+constexpr int kHexadecimalDigitLimit = kDecimalDigitLimit / 4;
+
+// The largest exponent we can read is 999999999 (per
+// kDecimalExponentDigitsMax), and the largest exponent adjustment we can get
+// from dropped mantissa digits is 2 * kDecimalDigitLimit, and the sum of these
+// comfortably fits in an integer.
+//
+// We count kDecimalDigitLimit twice because there are independent limits for
+// numbers before and after the decimal point. (In the case where there are no
+// significant digits before the decimal point, there are independent limits for
+// post-decimal-point leading zeroes and for significant digits.)
+static_assert(999999999 + 2 * kDecimalDigitLimit <
+ std::numeric_limits<int>::max(),
+ "int type too small");
+static_assert(999999999 + 2 * (4 * kHexadecimalDigitLimit) <
+ std::numeric_limits<int>::max(),
+ "int type too small");
+
+// Returns true if the provided bitfield allows parsing an exponent value
+// (e.g., "1.5e100").
+bool AllowExponent(chars_format flags) {
+ bool fixed = (flags & chars_format::fixed) == chars_format::fixed;
+ bool scientific =
+ (flags & chars_format::scientific) == chars_format::scientific;
+ return scientific || !fixed;
+}
+
+// Returns true if the provided bitfield requires an exponent value be present.
+bool RequireExponent(chars_format flags) {
+ bool fixed = (flags & chars_format::fixed) == chars_format::fixed;
+ bool scientific =
+ (flags & chars_format::scientific) == chars_format::scientific;
+ return scientific && !fixed;
+}
+
+const int8_t kAsciiToInt[256] = {
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8,
+ 9, -1, -1, -1, -1, -1, -1, -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1, -1};
+
+// Returns true if `ch` is a digit in the given base
+template <int base>
+bool IsDigit(char ch);
+
+// Converts a valid `ch` to its digit value in the given base.
+template <int base>
+unsigned ToDigit(char ch);
+
+// Returns true if `ch` is the exponent delimiter for the given base.
+template <int base>
+bool IsExponentCharacter(char ch);
+
+// Returns the maximum number of significant digits we will read for a float
+// in the given base.
+template <int base>
+constexpr int MantissaDigitsMax();
+
+// Returns the largest consecutive run of digits we will accept when parsing a
+// number in the given base.
+template <int base>
+constexpr int DigitLimit();
+
+// Returns the amount the exponent must be adjusted by for each dropped digit.
+// (For decimal this is 1, since the digits are in base 10 and the exponent base
+// is also 10, but for hexadecimal this is 4, since the digits are base 16 but
+// the exponent base is 2.)
+template <int base>
+constexpr int DigitMagnitude();
+
+template <>
+bool IsDigit<10>(char ch) {
+ return ch >= '0' && ch <= '9';
+}
+template <>
+bool IsDigit<16>(char ch) {
+ return kAsciiToInt[static_cast<unsigned char>(ch)] >= 0;
+}
+
+template <>
+unsigned ToDigit<10>(char ch) {
+ return ch - '0';
+}
+template <>
+unsigned ToDigit<16>(char ch) {
+ return kAsciiToInt[static_cast<unsigned char>(ch)];
+}
+
+template <>
+bool IsExponentCharacter<10>(char ch) {
+ return ch == 'e' || ch == 'E';
+}
+
+template <>
+bool IsExponentCharacter<16>(char ch) {
+ return ch == 'p' || ch == 'P';
+}
+
+template <>
+constexpr int MantissaDigitsMax<10>() {
+ return kDecimalMantissaDigitsMax;
+}
+template <>
+constexpr int MantissaDigitsMax<16>() {
+ return kHexadecimalMantissaDigitsMax;
+}
+
+template <>
+constexpr int DigitLimit<10>() {
+ return kDecimalDigitLimit;
+}
+template <>
+constexpr int DigitLimit<16>() {
+ return kHexadecimalDigitLimit;
+}
+
+template <>
+constexpr int DigitMagnitude<10>() {
+ return 1;
+}
+template <>
+constexpr int DigitMagnitude<16>() {
+ return 4;
+}
+
+// Reads decimal digits from [begin, end) into *out. Returns the number of
+// digits consumed.
+//
+// After max_digits has been read, keeps consuming characters, but no longer
+// adjusts *out. If a nonzero digit is dropped this way, *dropped_nonzero_digit
+// is set; otherwise, it is left unmodified.
+//
+// If no digits are matched, returns 0 and leaves *out unchanged.
+//
+// ConsumeDigits does not protect against overflow on *out; max_digits must
+// be chosen with respect to type T to avoid the possibility of overflow.
+template <int base, typename T>
+std::size_t ConsumeDigits(const char* begin, const char* end, int max_digits,
+ T* out, bool* dropped_nonzero_digit) {
+ if (base == 10) {
+ assert(max_digits <= std::numeric_limits<T>::digits10);
+ } else if (base == 16) {
+ assert(max_digits * 4 <= std::numeric_limits<T>::digits);
+ }
+ const char* const original_begin = begin;
+ T accumulator = *out;
+ const char* significant_digits_end =
+ (end - begin > max_digits) ? begin + max_digits : end;
+ while (begin < significant_digits_end && IsDigit<base>(*begin)) {
+ // Do not guard against *out overflow; max_digits was chosen to avoid this.
+ // Do assert against it, to detect problems in debug builds.
+ auto digit = static_cast<T>(ToDigit<base>(*begin));
+ assert(accumulator * base >= accumulator);
+ accumulator *= base;
+ assert(accumulator + digit >= accumulator);
+ accumulator += digit;
+ ++begin;
+ }
+ bool dropped_nonzero = false;
+ while (begin < end && IsDigit<base>(*begin)) {
+ dropped_nonzero = dropped_nonzero || (*begin != '0');
+ ++begin;
+ }
+ if (dropped_nonzero && dropped_nonzero_digit != nullptr) {
+ *dropped_nonzero_digit = true;
+ }
+ *out = accumulator;
+ return begin - original_begin;
+}
+
+// Returns true if `v` is one of the chars allowed inside parentheses following
+// a NaN.
+bool IsNanChar(char v) {
+ return (v == '_') || (v >= '0' && v <= '9') || (v >= 'a' && v <= 'z') ||
+ (v >= 'A' && v <= 'Z');
+}
+
+// Checks the range [begin, end) for a strtod()-formatted infinity or NaN. If
+// one is found, sets `out` appropriately and returns true.
+bool ParseInfinityOrNan(const char* begin, const char* end,
+ strings_internal::ParsedFloat* out) {
+ if (end - begin < 3) {
+ return false;
+ }
+ switch (*begin) {
+ case 'i':
+ case 'I': {
+ // An infinity std::string consists of the characters "inf" or "infinity",
+ // case insensitive.
+ if (strings_internal::memcasecmp(begin + 1, "nf", 2) != 0) {
+ return false;
+ }
+ out->type = strings_internal::FloatType::kInfinity;
+ if (end - begin >= 8 &&
+ strings_internal::memcasecmp(begin + 3, "inity", 5) == 0) {
+ out->end = begin + 8;
+ } else {
+ out->end = begin + 3;
+ }
+ return true;
+ }
+ case 'n':
+ case 'N': {
+ // A NaN consists of the characters "nan", case insensitive, optionally
+ // followed by a parenthesized sequence of zero or more alphanumeric
+ // characters and/or underscores.
+ if (strings_internal::memcasecmp(begin + 1, "an", 2) != 0) {
+ return false;
+ }
+ out->type = strings_internal::FloatType::kNan;
+ out->end = begin + 3;
+ // NaN is allowed to be followed by a parenthesized std::string, consisting of
+ // only the characters [a-zA-Z0-9_]. Match that if it's present.
+ begin += 3;
+ if (begin < end && *begin == '(') {
+ const char* nan_begin = begin + 1;
+ while (nan_begin < end && IsNanChar(*nan_begin)) {
+ ++nan_begin;
+ }
+ if (nan_begin < end && *nan_begin == ')') {
+ // We found an extra NaN specifier range
+ out->subrange_begin = begin + 1;
+ out->subrange_end = nan_begin;
+ out->end = nan_begin + 1;
+ }
+ }
+ return true;
+ }
+ default:
+ return false;
+ }
+}
+} // namespace
+
+namespace strings_internal {
+
+template <int base>
+strings_internal::ParsedFloat ParseFloat(const char* begin, const char* end,
+ chars_format format_flags) {
+ strings_internal::ParsedFloat result;
+
+ // Exit early if we're given an empty range.
+ if (begin == end) return result;
+
+ // Handle the infinity and NaN cases.
+ if (ParseInfinityOrNan(begin, end, &result)) {
+ return result;
+ }
+
+ const char* const mantissa_begin = begin;
+ while (begin < end && *begin == '0') {
+ ++begin; // skip leading zeros
+ }
+ uint64_t mantissa = 0;
+
+ int exponent_adjustment = 0;
+ bool mantissa_is_inexact = false;
+ std::size_t pre_decimal_digits = ConsumeDigits<base>(
+ begin, end, MantissaDigitsMax<base>(), &mantissa, &mantissa_is_inexact);
+ begin += pre_decimal_digits;
+ int digits_left;
+ if (pre_decimal_digits >= DigitLimit<base>()) {
+ // refuse to parse pathological inputs
+ return result;
+ } else if (pre_decimal_digits > MantissaDigitsMax<base>()) {
+ // We dropped some non-fraction digits on the floor. Adjust our exponent
+ // to compensate.
+ exponent_adjustment =
+ static_cast<int>(pre_decimal_digits - MantissaDigitsMax<base>());
+ digits_left = 0;
+ } else {
+ digits_left =
+ static_cast<int>(MantissaDigitsMax<base>() - pre_decimal_digits);
+ }
+ if (begin < end && *begin == '.') {
+ ++begin;
+ if (mantissa == 0) {
+ // If we haven't seen any nonzero digits yet, keep skipping zeros. We
+ // have to adjust the exponent to reflect the changed place value.
+ const char* begin_zeros = begin;
+ while (begin < end && *begin == '0') {
+ ++begin;
+ }
+ std::size_t zeros_skipped = begin - begin_zeros;
+ if (zeros_skipped >= DigitLimit<base>()) {
+ // refuse to parse pathological inputs
+ return result;
+ }
+ exponent_adjustment -= static_cast<int>(zeros_skipped);
+ }
+ std::size_t post_decimal_digits = ConsumeDigits<base>(
+ begin, end, digits_left, &mantissa, &mantissa_is_inexact);
+ begin += post_decimal_digits;
+
+ // Since `mantissa` is an integer, each significant digit we read after
+ // the decimal point requires an adjustment to the exponent. "1.23e0" will
+ // be stored as `mantissa` == 123 and `exponent` == -2 (that is,
+ // "123e-2").
+ if (post_decimal_digits >= DigitLimit<base>()) {
+ // refuse to parse pathological inputs
+ return result;
+ } else if (post_decimal_digits > digits_left) {
+ exponent_adjustment -= digits_left;
+ } else {
+ exponent_adjustment -= post_decimal_digits;
+ }
+ }
+ // If we've found no mantissa whatsoever, this isn't a number.
+ if (mantissa_begin == begin) {
+ return result;
+ }
+ // A bare "." doesn't count as a mantissa either.
+ if (begin - mantissa_begin == 1 && *mantissa_begin == '.') {
+ return result;
+ }
+
+ if (mantissa_is_inexact) {
+ // We dropped significant digits on the floor. Handle this appropriately.
+ if (base == 10) {
+ // If we truncated significant decimal digits, store the full range of the
+ // mantissa for future big integer math for exact rounding.
+ result.subrange_begin = mantissa_begin;
+ result.subrange_end = begin;
+ } else if (base == 16) {
+ // If we truncated hex digits, reflect this fact by setting the low
+ // ("sticky") bit. This allows for correct rounding in all cases.
+ mantissa |= 1;
+ }
+ }
+ result.mantissa = mantissa;
+
+ const char* const exponent_begin = begin;
+ result.literal_exponent = 0;
+ bool found_exponent = false;
+ if (AllowExponent(format_flags) && begin < end &&
+ IsExponentCharacter<base>(*begin)) {
+ bool negative_exponent = false;
+ ++begin;
+ if (begin < end && *begin == '-') {
+ negative_exponent = true;
+ ++begin;
+ } else if (begin < end && *begin == '+') {
+ ++begin;
+ }
+ const char* const exponent_digits_begin = begin;
+ // Exponent is always expressed in decimal, even for hexadecimal floats.
+ begin += ConsumeDigits<10>(begin, end, kDecimalExponentDigitsMax,
+ &result.literal_exponent, nullptr);
+ if (begin == exponent_digits_begin) {
+ // there were no digits where we expected an exponent. We failed to read
+ // an exponent and should not consume the 'e' after all. Rewind 'begin'.
+ found_exponent = false;
+ begin = exponent_begin;
+ } else {
+ found_exponent = true;
+ if (negative_exponent) {
+ result.literal_exponent = -result.literal_exponent;
+ }
+ }
+ }
+
+ if (!found_exponent && RequireExponent(format_flags)) {
+ // Provided flags required an exponent, but none was found. This results
+ // in a failure to scan.
+ return result;
+ }
+
+ // Success!
+ result.type = strings_internal::FloatType::kNumber;
+ if (result.mantissa > 0) {
+ result.exponent = result.literal_exponent +
+ (DigitMagnitude<base>() * exponent_adjustment);
+ } else {
+ result.exponent = 0;
+ }
+ result.end = begin;
+ return result;
+}
+
+template ParsedFloat ParseFloat<10>(const char* begin, const char* end,
+ chars_format format_flags);
+template ParsedFloat ParseFloat<16>(const char* begin, const char* end,
+ chars_format format_flags);
+
+} // namespace strings_internal
+} // inline namespace lts_2018_06_20
+} // namespace absl
diff --git a/absl/strings/internal/charconv_parse.h b/absl/strings/internal/charconv_parse.h
new file mode 100644
index 00000000..41f4f40d
--- /dev/null
+++ b/absl/strings/internal/charconv_parse.h
@@ -0,0 +1,98 @@
+// 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 {
+inline namespace lts_2018_06_20 {
+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
+} // inline namespace lts_2018_06_20
+} // namespace absl
+#endif // ABSL_STRINGS_INTERNAL_CHARCONV_PARSE_H_
diff --git a/absl/strings/internal/charconv_parse_test.cc b/absl/strings/internal/charconv_parse_test.cc
new file mode 100644
index 00000000..1ff86004
--- /dev/null
+++ b/absl/strings/internal/charconv_parse_test.cc
@@ -0,0 +1,357 @@
+// 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.
+
+#include "absl/strings/internal/charconv_parse.h"
+
+#include <string>
+#include <utility>
+
+#include "gmock/gmock.h"
+#include "gtest/gtest.h"
+#include "absl/base/internal/raw_logging.h"
+#include "absl/strings/str_cat.h"
+
+using absl::chars_format;
+using absl::strings_internal::FloatType;
+using absl::strings_internal::ParsedFloat;
+using absl::strings_internal::ParseFloat;
+
+namespace {
+
+// Check that a given std::string input is parsed to the expected mantissa and
+// exponent.
+//
+// Input std::string `s` must contain a '$' character. It marks the end of the
+// characters that should be consumed by the match. It is stripped from the
+// input to ParseFloat.
+//
+// If input std::string `s` contains '[' and ']' characters, these mark the region
+// of characters that should be marked as the "subrange". For NaNs, this is
+// the location of the extended NaN std::string. For numbers, this is the location
+// of the full, over-large mantissa.
+template <int base>
+void ExpectParsedFloat(std::string s, absl::chars_format format_flags,
+ FloatType expected_type, uint64_t expected_mantissa,
+ int expected_exponent,
+ int expected_literal_exponent = -999) {
+ SCOPED_TRACE(s);
+
+ int begin_subrange = -1;
+ int end_subrange = -1;
+ // If s contains '[' and ']', then strip these characters and set the subrange
+ // indices appropriately.
+ std::string::size_type open_bracket_pos = s.find('[');
+ if (open_bracket_pos != std::string::npos) {
+ begin_subrange = static_cast<int>(open_bracket_pos);
+ s.replace(open_bracket_pos, 1, "");
+ std::string::size_type close_bracket_pos = s.find(']');
+ ABSL_RAW_CHECK(close_bracket_pos != absl::string_view::npos,
+ "Test input contains [ without matching ]");
+ end_subrange = static_cast<int>(close_bracket_pos);
+ s.replace(close_bracket_pos, 1, "");
+ }
+ const std::string::size_type expected_characters_matched = s.find('$');
+ ABSL_RAW_CHECK(expected_characters_matched != std::string::npos,
+ "Input std::string must contain $");
+ s.replace(expected_characters_matched, 1, "");
+
+ ParsedFloat parsed =
+ ParseFloat<base>(s.data(), s.data() + s.size(), format_flags);
+
+ EXPECT_NE(parsed.end, nullptr);
+ if (parsed.end == nullptr) {
+ return; // The following tests are not useful if we fully failed to parse
+ }
+ EXPECT_EQ(parsed.type, expected_type);
+ if (begin_subrange == -1) {
+ EXPECT_EQ(parsed.subrange_begin, nullptr);
+ EXPECT_EQ(parsed.subrange_end, nullptr);
+ } else {
+ EXPECT_EQ(parsed.subrange_begin, s.data() + begin_subrange);
+ EXPECT_EQ(parsed.subrange_end, s.data() + end_subrange);
+ }
+ if (parsed.type == FloatType::kNumber) {
+ EXPECT_EQ(parsed.mantissa, expected_mantissa);
+ EXPECT_EQ(parsed.exponent, expected_exponent);
+ if (expected_literal_exponent != -999) {
+ EXPECT_EQ(parsed.literal_exponent, expected_literal_exponent);
+ }
+ }
+ auto characters_matched = static_cast<int>(parsed.end - s.data());
+ EXPECT_EQ(characters_matched, expected_characters_matched);
+}
+
+// Check that a given std::string input is parsed to the expected mantissa and
+// exponent.
+//
+// Input std::string `s` must contain a '$' character. It marks the end of the
+// characters that were consumed by the match.
+template <int base>
+void ExpectNumber(std::string s, absl::chars_format format_flags,
+ uint64_t expected_mantissa, int expected_exponent,
+ int expected_literal_exponent = -999) {
+ ExpectParsedFloat<base>(std::move(s), format_flags, FloatType::kNumber,
+ expected_mantissa, expected_exponent,
+ expected_literal_exponent);
+}
+
+// Check that a given std::string input is parsed to the given special value.
+//
+// This tests against both number bases, since infinities and NaNs have
+// identical representations in both modes.
+void ExpectSpecial(const std::string& s, absl::chars_format format_flags,
+ FloatType type) {
+ ExpectParsedFloat<10>(s, format_flags, type, 0, 0);
+ ExpectParsedFloat<16>(s, format_flags, type, 0, 0);
+}
+
+// Check that a given input std::string is not matched by Float.
+template <int base>
+void ExpectFailedParse(absl::string_view s, absl::chars_format format_flags) {
+ ParsedFloat parsed =
+ ParseFloat<base>(s.data(), s.data() + s.size(), format_flags);
+ EXPECT_EQ(parsed.end, nullptr);
+}
+
+TEST(ParseFloat, SimpleValue) {
+ // Test that various forms of floating point numbers all parse correctly.
+ ExpectNumber<10>("1.23456789e5$", chars_format::general, 123456789, -3);
+ ExpectNumber<10>("1.23456789e+5$", chars_format::general, 123456789, -3);
+ ExpectNumber<10>("1.23456789E5$", chars_format::general, 123456789, -3);
+ ExpectNumber<10>("1.23456789e05$", chars_format::general, 123456789, -3);
+ ExpectNumber<10>("123.456789e3$", chars_format::general, 123456789, -3);
+ ExpectNumber<10>("0.000123456789e9$", chars_format::general, 123456789, -3);
+ ExpectNumber<10>("123456.789$", chars_format::general, 123456789, -3);
+ ExpectNumber<10>("123456789e-3$", chars_format::general, 123456789, -3);
+
+ ExpectNumber<16>("1.234abcdefp28$", chars_format::general, 0x1234abcdef, -8);
+ ExpectNumber<16>("1.234abcdefp+28$", chars_format::general, 0x1234abcdef, -8);
+ ExpectNumber<16>("1.234ABCDEFp28$", chars_format::general, 0x1234abcdef, -8);
+ ExpectNumber<16>("1.234AbCdEfP0028$", chars_format::general, 0x1234abcdef,
+ -8);
+ ExpectNumber<16>("123.4abcdefp20$", chars_format::general, 0x1234abcdef, -8);
+ ExpectNumber<16>("0.0001234abcdefp44$", chars_format::general, 0x1234abcdef,
+ -8);
+ ExpectNumber<16>("1234abcd.ef$", chars_format::general, 0x1234abcdef, -8);
+ ExpectNumber<16>("1234abcdefp-8$", chars_format::general, 0x1234abcdef, -8);
+
+ // ExpectNumber does not attempt to drop trailing zeroes.
+ ExpectNumber<10>("0001.2345678900e005$", chars_format::general, 12345678900,
+ -5);
+ ExpectNumber<16>("0001.234abcdef000p28$", chars_format::general,
+ 0x1234abcdef000, -20);
+
+ // Ensure non-matching characters after a number are ignored, even when they
+ // look like potentially matching characters.
+ ExpectNumber<10>("1.23456789e5$ ", chars_format::general, 123456789, -3);
+ ExpectNumber<10>("1.23456789e5$e5e5", chars_format::general, 123456789, -3);
+ ExpectNumber<10>("1.23456789e5$.25", chars_format::general, 123456789, -3);
+ ExpectNumber<10>("1.23456789e5$-", chars_format::general, 123456789, -3);
+ ExpectNumber<10>("1.23456789e5$PUPPERS!!!", chars_format::general, 123456789,
+ -3);
+ ExpectNumber<10>("123456.789$efghij", chars_format::general, 123456789, -3);
+ ExpectNumber<10>("123456.789$e", chars_format::general, 123456789, -3);
+ ExpectNumber<10>("123456.789$p5", chars_format::general, 123456789, -3);
+ ExpectNumber<10>("123456.789$.10", chars_format::general, 123456789, -3);
+
+ ExpectNumber<16>("1.234abcdefp28$ ", chars_format::general, 0x1234abcdef,
+ -8);
+ ExpectNumber<16>("1.234abcdefp28$p28", chars_format::general, 0x1234abcdef,
+ -8);
+ ExpectNumber<16>("1.234abcdefp28$.125", chars_format::general, 0x1234abcdef,
+ -8);
+ ExpectNumber<16>("1.234abcdefp28$-", chars_format::general, 0x1234abcdef, -8);
+ ExpectNumber<16>("1.234abcdefp28$KITTEHS!!!", chars_format::general,
+ 0x1234abcdef, -8);
+ ExpectNumber<16>("1234abcd.ef$ghijk", chars_format::general, 0x1234abcdef,
+ -8);
+ ExpectNumber<16>("1234abcd.ef$p", chars_format::general, 0x1234abcdef, -8);
+ ExpectNumber<16>("1234abcd.ef$.10", chars_format::general, 0x1234abcdef, -8);
+
+ // Ensure we can read a full resolution mantissa without overflow.
+ ExpectNumber<10>("9999999999999999999$", chars_format::general,
+ 9999999999999999999u, 0);
+ ExpectNumber<16>("fffffffffffffff$", chars_format::general,
+ 0xfffffffffffffffu, 0);
+
+ // Check that zero is consistently read.
+ ExpectNumber<10>("0$", chars_format::general, 0, 0);
+ ExpectNumber<16>("0$", chars_format::general, 0, 0);
+ ExpectNumber<10>("000000000000000000000000000000000000000$",
+ chars_format::general, 0, 0);
+ ExpectNumber<16>("000000000000000000000000000000000000000$",
+ chars_format::general, 0, 0);
+ ExpectNumber<10>("0000000000000000000000.000000000000000000$",
+ chars_format::general, 0, 0);
+ ExpectNumber<16>("0000000000000000000000.000000000000000000$",
+ chars_format::general, 0, 0);
+ ExpectNumber<10>("0.00000000000000000000000000000000e123456$",
+ chars_format::general, 0, 0);
+ ExpectNumber<16>("0.00000000000000000000000000000000p123456$",
+ chars_format::general, 0, 0);
+}
+
+TEST(ParseFloat, LargeDecimalMantissa) {
+ // After 19 significant decimal digits in the mantissa, ParsedFloat will
+ // truncate additional digits. We need to test that:
+ // 1) the truncation to 19 digits happens
+ // 2) the returned exponent reflects the dropped significant digits
+ // 3) a correct literal_exponent is set
+ //
+ // If and only if a significant digit is found after 19 digits, then the
+ // entirety of the mantissa in case the exact value is needed to make a
+ // rounding decision. The [ and ] characters below denote where such a
+ // subregion was marked by by ParseFloat. They are not part of the input.
+
+ // Mark a capture group only if a dropped digit is significant (nonzero).
+ ExpectNumber<10>("100000000000000000000000000$", chars_format::general,
+ 1000000000000000000,
+ /* adjusted exponent */ 8);
+
+ ExpectNumber<10>("123456789123456789100000000$", chars_format::general,
+ 1234567891234567891,
+ /* adjusted exponent */ 8);
+
+ ExpectNumber<10>("[123456789123456789123456789]$", chars_format::general,
+ 1234567891234567891,
+ /* adjusted exponent */ 8,
+ /* literal exponent */ 0);
+
+ ExpectNumber<10>("[123456789123456789100000009]$", chars_format::general,
+ 1234567891234567891,
+ /* adjusted exponent */ 8,
+ /* literal exponent */ 0);
+
+ ExpectNumber<10>("[123456789123456789120000000]$", chars_format::general,
+ 1234567891234567891,
+ /* adjusted exponent */ 8,
+ /* literal exponent */ 0);
+
+ // Leading zeroes should not count towards the 19 significant digit limit
+ ExpectNumber<10>("[00000000123456789123456789123456789]$",
+ chars_format::general, 1234567891234567891,
+ /* adjusted exponent */ 8,
+ /* literal exponent */ 0);
+
+ ExpectNumber<10>("00000000123456789123456789100000000$",
+ chars_format::general, 1234567891234567891,
+ /* adjusted exponent */ 8);
+
+ // Truncated digits after the decimal point should not cause a further
+ // exponent adjustment.
+ ExpectNumber<10>("1.234567891234567891e123$", chars_format::general,
+ 1234567891234567891, 105);
+ ExpectNumber<10>("[1.23456789123456789123456789]e123$", chars_format::general,
+ 1234567891234567891,
+ /* adjusted exponent */ 105,
+ /* literal exponent */ 123);
+
+ // Ensure we truncate, and not round. (The from_chars algorithm we use
+ // depends on our guess missing low, if it misses, so we need the rounding
+ // error to be downward.)
+ ExpectNumber<10>("[1999999999999999999999]$", chars_format::general,
+ 1999999999999999999,
+ /* adjusted exponent */ 3,
+ /* literal exponent */ 0);
+}
+
+TEST(ParseFloat, LargeHexadecimalMantissa) {
+ // After 15 significant hex digits in the mantissa, ParsedFloat will treat
+ // additional digits as sticky, We need to test that:
+ // 1) The truncation to 15 digits happens
+ // 2) The returned exponent reflects the dropped significant digits
+ // 3) If a nonzero digit is dropped, the low bit of mantissa is set.
+
+ ExpectNumber<16>("123456789abcdef123456789abcdef$", chars_format::general,
+ 0x123456789abcdef, 60);
+
+ // Leading zeroes should not count towards the 15 significant digit limit
+ ExpectNumber<16>("000000123456789abcdef123456789abcdef$",
+ chars_format::general, 0x123456789abcdef, 60);
+
+ // Truncated digits after the radix point should not cause a further
+ // exponent adjustment.
+ ExpectNumber<16>("1.23456789abcdefp100$", chars_format::general,
+ 0x123456789abcdef, 44);
+ ExpectNumber<16>("1.23456789abcdef123456789abcdefp100$",
+ chars_format::general, 0x123456789abcdef, 44);
+
+ // test sticky digit behavior. The low bit should be set iff any dropped
+ // digit is nonzero.
+ ExpectNumber<16>("123456789abcdee123456789abcdee$", chars_format::general,
+ 0x123456789abcdef, 60);
+ ExpectNumber<16>("123456789abcdee000000000000001$", chars_format::general,
+ 0x123456789abcdef, 60);
+ ExpectNumber<16>("123456789abcdee000000000000000$", chars_format::general,
+ 0x123456789abcdee, 60);
+}
+
+TEST(ParseFloat, ScientificVsFixed) {
+ // In fixed mode, an exponent is never matched (but the remainder of the
+ // number will be matched.)
+ ExpectNumber<10>("1.23456789$e5", chars_format::fixed, 123456789, -8);
+ ExpectNumber<10>("123456.789$", chars_format::fixed, 123456789, -3);
+ ExpectNumber<16>("1.234abcdef$p28", chars_format::fixed, 0x1234abcdef, -36);
+ ExpectNumber<16>("1234abcd.ef$", chars_format::fixed, 0x1234abcdef, -8);
+
+ // In scientific mode, numbers don't match *unless* they have an exponent.
+ ExpectNumber<10>("1.23456789e5$", chars_format::scientific, 123456789, -3);
+ ExpectFailedParse<10>("-123456.789$", chars_format::scientific);
+ ExpectNumber<16>("1.234abcdefp28$", chars_format::scientific, 0x1234abcdef,
+ -8);
+ ExpectFailedParse<16>("1234abcd.ef$", chars_format::scientific);
+}
+
+TEST(ParseFloat, Infinity) {
+ ExpectFailedParse<10>("in", chars_format::general);
+ ExpectFailedParse<16>("in", chars_format::general);
+ ExpectFailedParse<10>("inx", chars_format::general);
+ ExpectFailedParse<16>("inx", chars_format::general);
+ ExpectSpecial("inf$", chars_format::general, FloatType::kInfinity);
+ ExpectSpecial("Inf$", chars_format::general, FloatType::kInfinity);
+ ExpectSpecial("INF$", chars_format::general, FloatType::kInfinity);
+ ExpectSpecial("inf$inite", chars_format::general, FloatType::kInfinity);
+ ExpectSpecial("iNfInItY$", chars_format::general, FloatType::kInfinity);
+ ExpectSpecial("infinity$!!!", chars_format::general, FloatType::kInfinity);
+}
+
+TEST(ParseFloat, NaN) {
+ ExpectFailedParse<10>("na", chars_format::general);
+ ExpectFailedParse<16>("na", chars_format::general);
+ ExpectFailedParse<10>("nah", chars_format::general);
+ ExpectFailedParse<16>("nah", chars_format::general);
+ ExpectSpecial("nan$", chars_format::general, FloatType::kNan);
+ ExpectSpecial("NaN$", chars_format::general, FloatType::kNan);
+ ExpectSpecial("nAn$", chars_format::general, FloatType::kNan);
+ ExpectSpecial("NAN$", chars_format::general, FloatType::kNan);
+ ExpectSpecial("NaN$aNaNaNaNaBatman!", chars_format::general, FloatType::kNan);
+
+ // A parenthesized sequence of the characters [a-zA-Z0-9_] is allowed to
+ // appear after an NaN. Check that this is allowed, and that the correct
+ // characters are grouped.
+ //
+ // (The characters [ and ] in the pattern below delimit the expected matched
+ // subgroup; they are not part of the input passed to ParseFloat.)
+ ExpectSpecial("nan([0xabcdef])$", chars_format::general, FloatType::kNan);
+ ExpectSpecial("nan([0xabcdef])$...", chars_format::general, FloatType::kNan);
+ ExpectSpecial("nan([0xabcdef])$)...", chars_format::general, FloatType::kNan);
+ ExpectSpecial("nan([])$", chars_format::general, FloatType::kNan);
+ ExpectSpecial("nan([aAzZ09_])$", chars_format::general, FloatType::kNan);
+ // If the subgroup contains illegal characters, don't match it at all.
+ ExpectSpecial("nan$(bad-char)", chars_format::general, FloatType::kNan);
+ // Also cope with a missing close paren.
+ ExpectSpecial("nan$(0xabcdef", chars_format::general, FloatType::kNan);
+}
+
+} // namespace
diff --git a/absl/strings/internal/escaping_test_common.h b/absl/strings/internal/escaping_test_common.h
index cc41f431..478e0582 100644
--- a/absl/strings/internal/escaping_test_common.h
+++ b/absl/strings/internal/escaping_test_common.h
@@ -22,6 +22,7 @@
#include "absl/strings/string_view.h"
namespace absl {
+inline namespace lts_2018_06_20 {
namespace strings_internal {
struct base64_testcase {
@@ -126,6 +127,7 @@ inline const std::array<base64_testcase, 5>& base64_strings() {
}
} // namespace strings_internal
+} // inline namespace lts_2018_06_20
} // namespace absl
#endif // ABSL_STRINGS_INTERNAL_ESCAPING_TEST_COMMON_H_
diff --git a/absl/strings/internal/memutil.cc b/absl/strings/internal/memutil.cc
index a0de70df..13ad686c 100644
--- a/absl/strings/internal/memutil.cc
+++ b/absl/strings/internal/memutil.cc
@@ -17,6 +17,7 @@
#include <cstdlib>
namespace absl {
+inline namespace lts_2018_06_20 {
namespace strings_internal {
int memcasecmp(const char* s1, const char* s2, size_t len) {
@@ -107,4 +108,5 @@ const char* memmatch(const char* phaystack, size_t haylen, const char* pneedle,
}
} // namespace strings_internal
+} // inline namespace lts_2018_06_20
} // namespace absl
diff --git a/absl/strings/internal/memutil.h b/absl/strings/internal/memutil.h
index a6f1c691..828b01d5 100644
--- a/absl/strings/internal/memutil.h
+++ b/absl/strings/internal/memutil.h
@@ -69,6 +69,7 @@
#include "absl/strings/ascii.h" // for absl::ascii_tolower
namespace absl {
+inline namespace lts_2018_06_20 {
namespace strings_internal {
inline char* memcat(char* dest, size_t destlen, const char* src,
@@ -141,6 +142,7 @@ const char* memmatch(const char* phaystack, size_t haylen, const char* pneedle,
size_t neelen);
} // namespace strings_internal
+} // inline namespace lts_2018_06_20
} // namespace absl
#endif // ABSL_STRINGS_INTERNAL_MEMUTIL_H_
diff --git a/absl/strings/internal/numbers_test_common.h b/absl/strings/internal/numbers_test_common.h
index 20e3af51..a511dcf7 100644
--- a/absl/strings/internal/numbers_test_common.h
+++ b/absl/strings/internal/numbers_test_common.h
@@ -24,6 +24,7 @@
#include <string>
namespace absl {
+inline namespace lts_2018_06_20 {
namespace strings_internal {
template <typename IntType>
@@ -173,6 +174,7 @@ inline const std::array<uint64_test_case, 34>& strtouint64_test_cases() {
}
} // namespace strings_internal
+} // inline namespace lts_2018_06_20
} // namespace absl
#endif // ABSL_STRINGS_INTERNAL_NUMBERS_TEST_COMMON_H_
diff --git a/absl/strings/internal/ostringstream.cc b/absl/strings/internal/ostringstream.cc
index 6ee2b109..9fe5b3c5 100644
--- a/absl/strings/internal/ostringstream.cc
+++ b/absl/strings/internal/ostringstream.cc
@@ -15,6 +15,7 @@
#include "absl/strings/internal/ostringstream.h"
namespace absl {
+inline namespace lts_2018_06_20 {
namespace strings_internal {
OStringStream::Buf::int_type OStringStream::overflow(int c) {
@@ -31,4 +32,5 @@ std::streamsize OStringStream::xsputn(const char* s, std::streamsize n) {
}
} // namespace strings_internal
+} // inline namespace lts_2018_06_20
} // namespace absl
diff --git a/absl/strings/internal/ostringstream.h b/absl/strings/internal/ostringstream.h
index 6e1325b9..66ae3c29 100644
--- a/absl/strings/internal/ostringstream.h
+++ b/absl/strings/internal/ostringstream.h
@@ -23,6 +23,7 @@
#include "absl/base/port.h"
namespace absl {
+inline namespace lts_2018_06_20 {
namespace strings_internal {
// The same as std::ostringstream but appends to a user-specified std::string,
@@ -82,6 +83,7 @@ class OStringStream : private std::basic_streambuf<char>, public std::ostream {
};
} // namespace strings_internal
+} // inline namespace lts_2018_06_20
} // namespace absl
#endif // ABSL_STRINGS_INTERNAL_OSTRINGSTREAM_H_
diff --git a/absl/strings/internal/resize_uninitialized.h b/absl/strings/internal/resize_uninitialized.h
index 0157ca02..b3690332 100644
--- a/absl/strings/internal/resize_uninitialized.h
+++ b/absl/strings/internal/resize_uninitialized.h
@@ -24,6 +24,7 @@
#include "absl/meta/type_traits.h" // for void_t
namespace absl {
+inline namespace lts_2018_06_20 {
namespace strings_internal {
// Is a subclass of true_type or false_type, depending on whether or not
@@ -64,6 +65,7 @@ inline void STLStringResizeUninitialized(string_type* s, size_t new_size) {
}
} // namespace strings_internal
+} // inline namespace lts_2018_06_20
} // namespace absl
#endif // ABSL_STRINGS_INTERNAL_RESIZE_UNINITIALIZED_H_
diff --git a/absl/strings/internal/stl_type_traits.h b/absl/strings/internal/stl_type_traits.h
index 04c4a532..7fc56a3c 100644
--- a/absl/strings/internal/stl_type_traits.h
+++ b/absl/strings/internal/stl_type_traits.h
@@ -40,6 +40,7 @@
#include "absl/meta/type_traits.h"
namespace absl {
+inline namespace lts_2018_06_20 {
namespace strings_internal {
template <typename C, template <typename...> class T>
@@ -242,5 +243,6 @@ struct IsStrictlyBaseOfAndConvertibleToSTLContainer
IsConvertibleToSTLContainer<C>> {};
} // namespace strings_internal
+} // inline namespace lts_2018_06_20
} // namespace absl
#endif // ABSL_STRINGS_INTERNAL_STL_TYPE_TRAITS_H_
diff --git a/absl/strings/internal/str_join_internal.h b/absl/strings/internal/str_join_internal.h
index a734758c..5834403e 100644
--- a/absl/strings/internal/str_join_internal.h
+++ b/absl/strings/internal/str_join_internal.h
@@ -43,6 +43,7 @@
#include "absl/strings/str_cat.h"
namespace absl {
+inline namespace lts_2018_06_20 {
namespace strings_internal {
//
@@ -306,6 +307,7 @@ std::string JoinRange(const Range& range, absl::string_view separator) {
}
} // namespace strings_internal
+} // inline namespace lts_2018_06_20
} // namespace absl
#endif // ABSL_STRINGS_INTERNAL_STR_JOIN_INTERNAL_H_
diff --git a/absl/strings/internal/str_split_internal.h b/absl/strings/internal/str_split_internal.h
index a1b10f3a..e2d2c6b0 100644
--- a/absl/strings/internal/str_split_internal.h
+++ b/absl/strings/internal/str_split_internal.h
@@ -47,6 +47,7 @@
#endif // _GLIBCXX_DEBUG
namespace absl {
+inline namespace lts_2018_06_20 {
namespace strings_internal {
// This class is implicitly constructible from everything that absl::string_view
@@ -430,6 +431,7 @@ class Splitter {
};
} // namespace strings_internal
+} // inline namespace lts_2018_06_20
} // namespace absl
#endif // ABSL_STRINGS_INTERNAL_STR_SPLIT_INTERNAL_H_
diff --git a/absl/strings/internal/utf8.cc b/absl/strings/internal/utf8.cc
index 2415c2cc..81b6241b 100644
--- a/absl/strings/internal/utf8.cc
+++ b/absl/strings/internal/utf8.cc
@@ -17,6 +17,7 @@
#include "absl/strings/internal/utf8.h"
namespace absl {
+inline namespace lts_2018_06_20 {
namespace strings_internal {
size_t EncodeUTF8Char(char *buffer, char32_t utf8_char) {
@@ -48,4 +49,5 @@ size_t EncodeUTF8Char(char *buffer, char32_t utf8_char) {
}
} // namespace strings_internal
+} // inline namespace lts_2018_06_20
} // namespace absl
diff --git a/absl/strings/internal/utf8.h b/absl/strings/internal/utf8.h
index d2c3c0b0..5a94ae6f 100644
--- a/absl/strings/internal/utf8.h
+++ b/absl/strings/internal/utf8.h
@@ -22,6 +22,7 @@
#include <cstdint>
namespace absl {
+inline namespace lts_2018_06_20 {
namespace strings_internal {
// For Unicode code points 0 through 0x10FFFF, EncodeUTF8Char writes
@@ -42,6 +43,7 @@ enum { kMaxEncodedUTF8Size = 4 };
size_t EncodeUTF8Char(char *buffer, char32_t utf8_char);
} // namespace strings_internal
+} // inline namespace lts_2018_06_20
} // namespace absl
#endif // ABSL_STRINGS_INTERNAL_UTF8_H_