tvl-depot/absl/time/internal/cctz/src/time_zone_fixed.cc
Abseil Team 256be56344 Export of internal Abseil changes.
--
00d42e3d5433aaf29c2ed293520b2ba178ae8bdb by Greg Falcon <gfalcon@google.com>:

Import of CCTZ from GitHub.

PiperOrigin-RevId: 238061818

--
867a7ca318fac2991ea9a4107dbae3cc9fbf974a by Abseil Team <absl-team@google.com>:

Added a IWYU export pragma when including a standard header for the purpose of aliasing its symbols.

PiperOrigin-RevId: 238022277

--
17047745058f2f151cd986ea9f649512542d3876 by Matt Armstrong <marmstrong@google.com>:

Clarify the comment discouraging WrapUnique<T>(x) calls.

PiperOrigin-RevId: 237873803

--
3dcb2e4968243d33ca0ce53280c445df50f4a7ec by Samuel Benzaquen <sbenza@google.com>:

Workaround clang bug https://bugs.llvm.org/show_bug.cgi?id=38289

PiperOrigin-RevId: 237873551

--
f348d2dc7087a990cbdfb95aa51fd7ff478ae40e by Samuel Benzaquen <sbenza@google.com>:

Reduce minimum capacity to 1.
This reduces memory usage for small tables.
A flat_hash_set<int> of 1 element goes from 92 bytes to 24.
A flat_hash_set<string> of 1 element goes from 512 bytes to 56.

PiperOrigin-RevId: 237859811

--
9c8125be5e4e5d22a7bb62bdec8c323338385c1b by Jon Cohen <cohenjon@google.com>:

Bump to CMake 3.5. This is the oldest modern cmake being included by default in most popular OS distributions according to https://repology.org/project/cmake/versions.  Specifically, Ubuntu LTS 16.04 uses cmake 3.5 (https://packages.ubuntu.com/xenial/cmake)

PiperOrigin-RevId: 237859345

--
07638d672e0a4dced986a62750cfd8318ed36ffa by Derek Mauro <dmauro@google.com>:

Import of CCTZ from GitHub.

PiperOrigin-RevId: 237714597
GitOrigin-RevId: 00d42e3d5433aaf29c2ed293520b2ba178ae8bdb
Change-Id: I5faecc45add4a5a774d4f9baf06e5519091f2ccc
2019-03-12 15:07:34 -04:00

138 lines
4.1 KiB
C++

// Copyright 2016 Google Inc. All Rights Reserved.
//
// 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
//
// https://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 "time_zone_fixed.h"
#include <algorithm>
#include <cassert>
#include <chrono>
#include <cstring>
#include <string>
namespace absl {
namespace time_internal {
namespace cctz {
namespace {
// The prefix used for the internal names of fixed-offset zones.
const char kFixedOffsetPrefix[] = "Fixed/UTC";
const char kDigits[] = "0123456789";
char* Format02d(char* p, int v) {
*p++ = kDigits[(v / 10) % 10];
*p++ = kDigits[v % 10];
return p;
}
int Parse02d(const char* p) {
if (const char* ap = std::strchr(kDigits, *p)) {
int v = static_cast<int>(ap - kDigits);
if (const char* bp = std::strchr(kDigits, *++p)) {
return (v * 10) + static_cast<int>(bp - kDigits);
}
}
return -1;
}
} // namespace
bool FixedOffsetFromName(const std::string& name, seconds* offset) {
if (name.compare(0, std::string::npos, "UTC", 3) == 0) {
*offset = seconds::zero();
return true;
}
const std::size_t prefix_len = sizeof(kFixedOffsetPrefix) - 1;
const char* const ep = kFixedOffsetPrefix + prefix_len;
if (name.size() != prefix_len + 9) // <prefix>+99:99:99
return false;
if (!std::equal(kFixedOffsetPrefix, ep, name.begin()))
return false;
const char* np = name.data() + prefix_len;
if (np[0] != '+' && np[0] != '-')
return false;
if (np[3] != ':' || np[6] != ':') // see note below about large offsets
return false;
int hours = Parse02d(np + 1);
if (hours == -1) return false;
int mins = Parse02d(np + 4);
if (mins == -1) return false;
int secs = Parse02d(np + 7);
if (secs == -1) return false;
secs += ((hours * 60) + mins) * 60;
if (secs > 24 * 60 * 60) return false; // outside supported offset range
*offset = seconds(secs * (np[0] == '-' ? -1 : 1)); // "-" means west
return true;
}
std::string FixedOffsetToName(const seconds& offset) {
if (offset == seconds::zero()) return "UTC";
if (offset < std::chrono::hours(-24) || offset > std::chrono::hours(24)) {
// We don't support fixed-offset zones more than 24 hours
// away from UTC to avoid complications in rendering such
// offsets and to (somewhat) limit the total number of zones.
return "UTC";
}
int seconds = static_cast<int>(offset.count());
const char sign = (seconds < 0 ? '-' : '+');
int minutes = seconds / 60;
seconds %= 60;
if (sign == '-') {
if (seconds > 0) {
seconds -= 60;
minutes += 1;
}
seconds = -seconds;
minutes = -minutes;
}
int hours = minutes / 60;
minutes %= 60;
char buf[sizeof(kFixedOffsetPrefix) - 1 + sizeof("-24:00:00")];
std::strcpy(buf, kFixedOffsetPrefix);
char* ep = buf + sizeof(kFixedOffsetPrefix) - 1;
*ep++ = sign;
ep = Format02d(ep, hours);
*ep++ = ':';
ep = Format02d(ep, minutes);
*ep++ = ':';
ep = Format02d(ep, seconds);
*ep++ = '\0';
assert(ep == buf + sizeof(buf));
return buf;
}
std::string FixedOffsetToAbbr(const seconds& offset) {
std::string abbr = FixedOffsetToName(offset);
const std::size_t prefix_len = sizeof(kFixedOffsetPrefix) - 1;
if (abbr.size() == prefix_len + 9) { // <prefix>+99:99:99
abbr.erase(0, prefix_len); // +99:99:99
abbr.erase(6, 1); // +99:9999
abbr.erase(3, 1); // +999999
if (abbr[5] == '0' && abbr[6] == '0') { // +999900
abbr.erase(5, 2); // +9999
if (abbr[3] == '0' && abbr[4] == '0') { // +9900
abbr.erase(3, 2); // +99
}
}
}
return abbr;
}
} // namespace cctz
} // namespace time_internal
} // namespace absl