tzdb.h

Go to the documentation of this file.

/****
 * tzdb.h - Time Zone database support
 *
 * This file is part of the Timezone Library
 *
 * This library is free software: you can redistribute it and/or modify it under the terms of the
 * GNU General Public License as published by the Free Software Foundation, version 3 or later.
 *
 * This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
 * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along with this library.
 * If not, see <https://www.gnu.org/licenses/>.
 *
 ****/
 
#pragma once
 
#include "Timezone.h"
#include <FlashString/Array.hpp>
#include <FlashString/Vector.hpp>
#include <FlashString/Map.hpp>
 
#if TZINFO_WANT_NAME
#define TZINFO_FIELD_NAME area,
#else
#define TZINFO_FIELD_NAME
#endif
 
#if TZINFO_WANT_TZSTR
#define TZINFO_FIELD_TZSTR tzstr,
#else
#define TZINFO_FIELD_TZSTR
#endif
 
#if TZINFO_WANT_RULES
#define TZINFO_FIELD_RULES dst_rule, std_rule,
#else
#define TZINFO_FIELD_RULES
#endif
 
#if TZINFO_WANT_TRANSITIONS
#define TZINFO_FIELD_TRANSITIONS tznames, transitions,
#else
#define TZINFO_FIELD_TRANSITIONS
#endif
 
// clang-format off
#define DEFINE_REF_LOCAL(name, refname) \
    static constexpr decltype(refname)& name = refname;
 
#define TZ_DEFINE_RULE_LOCAL(name, ...) \
    static constexpr const Rule name PROGMEM {__VA_ARGS__};
 
#define TZ_DEFINE_PSTR_LOCAL(name, s) \
    static constexpr const char* name PROGMEM_PSTR  = s;
 
#define TIMEZONE_BEGIN(clsname, area_, location_) \
    class clsname : public Timezone { \
    public: \
        clsname() : Timezone(fromPosix(tzstr)) { } \
        TZ_DEFINE_PSTR_LOCAL(location, location_)
 
#define TIMEZONE_END() \
    static constexpr const Info info PROGMEM { \
        location, \
        TZINFO_FIELD_NAME \
        TZINFO_FIELD_TZSTR \
        TZINFO_FIELD_RULES \
        TZINFO_FIELD_TRANSITIONS \
        }; \
    };
// clang-format on
 
namespace TZ
{
struct Transition {
    int64_t time : 40;
    uint8_t desigidx : 8;
    int16_t offsetMins : 15;
    bool isdst : 1;
 
    operator time_t() const
    {
        return time;
    }
 
    time_t local() const
    {
        return time + (offsetMins * 60);
    }
};
 
#ifndef __WIN32
static_assert(sizeof(Transition) == 8, "Bad Transition def");
#endif
 
static constexpr const Rule PROGMEM rule_none{};
DEFINE_FSTR_ARRAY_LOCAL(transitions_none, Transition)
 
struct Info {
    PGM_P location;
#if TZINFO_WANT_NAME
    const FSTR::String& area;
#endif
#if TZINFO_WANT_TZSTR
    PGM_P tzstr;
#endif
#if TZINFO_WANT_RULE
    const Rule& dstStart;
    const Rule& stdStart;
#endif
#if TZINFO_WANT_TRANSITIONS
    PGM_P tznames;
    const FSTR::Array<Transition>& transitions;
#endif
 
#if TZINFO_WANT_NAME
    String name() const
    {
        String s;
        s += area;
        s += '/';
        s += location;
        return s;
    }
#endif
 
    operator Timezone() const
    {
#if TZINFO_WANT_TZSTR
        return Timezone::fromPosix(tzstr);
#elif TZINFO_WANT_RULE
        return Timezone(dstStart, stdStart);
#endif
    }
 
#if TZINFO_WANT_TRANSITIONS
    DateTime::ZoneInfo getInfo(const Transition& tt) const
    {
        return DateTime::ZoneInfo{
            .tag = Rule::Tag::fromString(&tznames[tt.desigidx]),
            .offsetMins = tt.offsetMins,
            .isDst = tt.isdst,
        };
    }
#endif
 
    explicit operator bool() const
    {
        return location;
    }
 
    static const Info& empty();
};
 
using ZoneList = FSTR::Vector<Info>;
using AreaMap = FSTR::Map<FSTR::String, ZoneList>;
 
DECLARE_FSTR_MAP(areas, FSTR::String, ZoneList)
 
 
const Info* findZone(const String& name);
 
} // namespace TZ