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Diffstat (limited to 'third_party/abseil_cpp/absl/time/internal/cctz/src/time_zone_fixed.cc')
-rw-r--r-- | third_party/abseil_cpp/absl/time/internal/cctz/src/time_zone_fixed.cc | 140 |
1 files changed, 140 insertions, 0 deletions
diff --git a/third_party/abseil_cpp/absl/time/internal/cctz/src/time_zone_fixed.cc b/third_party/abseil_cpp/absl/time/internal/cctz/src/time_zone_fixed.cc new file mode 100644 index 000000000000..303c0244a824 --- /dev/null +++ b/third_party/abseil_cpp/absl/time/internal/cctz/src/time_zone_fixed.cc @@ -0,0 +1,140 @@ +// 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> + +#include "absl/base/config.h" + +namespace absl { +ABSL_NAMESPACE_BEGIN +namespace time_internal { +namespace cctz { + +namespace { + +// The prefix used for the internal names of fixed-offset zones. +const char kFixedZonePrefix[] = "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(kFixedZonePrefix) - 1; + const char* const ep = kFixedZonePrefix + prefix_len; + if (name.size() != prefix_len + 9) // <prefix>+99:99:99 + return false; + if (!std::equal(kFixedZonePrefix, 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 offset_seconds = static_cast<int>(offset.count()); + const char sign = (offset_seconds < 0 ? '-' : '+'); + int offset_minutes = offset_seconds / 60; + offset_seconds %= 60; + if (sign == '-') { + if (offset_seconds > 0) { + offset_seconds -= 60; + offset_minutes += 1; + } + offset_seconds = -offset_seconds; + offset_minutes = -offset_minutes; + } + int offset_hours = offset_minutes / 60; + offset_minutes %= 60; + const std::size_t prefix_len = sizeof(kFixedZonePrefix) - 1; + char buf[prefix_len + sizeof("-24:00:00")]; + char* ep = std::copy(kFixedZonePrefix, kFixedZonePrefix + prefix_len, buf); + *ep++ = sign; + ep = Format02d(ep, offset_hours); + *ep++ = ':'; + ep = Format02d(ep, offset_minutes); + *ep++ = ':'; + ep = Format02d(ep, offset_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(kFixedZonePrefix) - 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 +ABSL_NAMESPACE_END +} // namespace absl |