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package org.jruby.util;

import org.jcodings.Encoding;
import org.jruby.*;
import org.jruby.runtime.ThreadContext;
import org.jruby.runtime.builtin.IRubyObject;

import java.math.BigInteger;
import java.util.List;

import static org.jruby.util.StrptimeParser.FormatBag.has;

This class has StrptimeParser and provides methods that are calls from JRuby. /**
 * This class has {@code StrptimeParser} and provides methods that are calls from JRuby.
 */
public class RubyDateParser {

    
Date._strptime method in JRuby 9.1.5.0's lib/ruby/stdlib/date/format.rb is replaced
with this method. This is Java implementation of date__strptime method in MRI 2.3.1's
ext/date/date_strptime.c.
See:
 https://github.com/jruby/jruby/blob/036ce39f0476d4bd718e23e64caff36bb50b8dbc/lib/ruby/stdlib/date/format.rb
 https://github.com/ruby/ruby/blob/394fa89c67722d35bdda89f10c7de5c304a5efb1/ext/date/date_strptime.c
/**
     * Date._strptime method in JRuby 9.1.5.0's lib/ruby/stdlib/date/format.rb is replaced
     * with this method. This is Java implementation of date__strptime method in MRI 2.3.1's
     * ext/date/date_strptime.c.
     * See:
     *  https://github.com/jruby/jruby/blob/036ce39f0476d4bd718e23e64caff36bb50b8dbc/lib/ruby/stdlib/date/format.rb
     *  https://github.com/ruby/ruby/blob/394fa89c67722d35bdda89f10c7de5c304a5efb1/ext/date/date_strptime.c
     */

    public IRubyObject parse(ThreadContext context, final RubyString format, final RubyString text) {
        return parse(context, format.asJavaString(), text);
    }

    public IRubyObject parse(ThreadContext context, final String format, final RubyString text) {
        final List<StrptimeToken> compiledPattern = context.runtime.getCachedStrptimePattern(format);
        final StrptimeParser.FormatBag bag = new StrptimeParser().parse(compiledPattern, text.asJavaString());

        return bag == null ? context.nil : convertFormatBagToHash(context, bag, text.getEncoding(), text.isTaint());
    }

    static RubyHash convertFormatBagToHash(ThreadContext context, StrptimeParser.FormatBag bag,
                                           Encoding encoding, boolean tainted) {
        final Ruby runtime = context.runtime;
        final RubyHash hash = RubyHash.newHash(runtime);

        if (has(bag.getMDay())) setHashValue(runtime, hash, "mday", runtime.newFixnum(bag.getMDay()));
        if (has(bag.getWDay())) setHashValue(runtime, hash, "wday", runtime.newFixnum(bag.getWDay()));
        if (has(bag.getCWDay())) setHashValue(runtime, hash, "cwday", runtime.newFixnum(bag.getCWDay()));
        if (has(bag.getYDay())) setHashValue(runtime, hash, "yday", runtime.newFixnum(bag.getYDay()));
        if (has(bag.getCWeek())) setHashValue(runtime, hash, "cweek", runtime.newFixnum(bag.getCWeek()));
        if (has(bag.getCWYear())) setHashValue(runtime, hash, "cwyear", RubyBignum.newBignum(runtime, bag.getCWYear()));
        if (has(bag.getMin())) setHashValue(runtime, hash, "min", runtime.newFixnum(bag.getMin()));
        if (has(bag.getMon())) setHashValue(runtime, hash, "mon", runtime.newFixnum(bag.getMon()));
        if (has(bag.getHour())) setHashValue(runtime, hash, "hour", runtime.newFixnum(bag.getHour()));
        if (has(bag.getYear())) setHashValue(runtime, hash, "year", RubyBignum.newBignum(runtime, bag.getYear()));
        if (has(bag.getSec())) setHashValue(runtime, hash, "sec", runtime.newFixnum(bag.getSec()));
        if (has(bag.getWNum0())) setHashValue(runtime, hash, "wnum0", runtime.newFixnum(bag.getWNum0()));
        if (has(bag.getWNum1())) setHashValue(runtime, hash, "wnum1", runtime.newFixnum(bag.getWNum1()));

        if (bag.getZone() != null) {
            final RubyString zone = RubyString.newString(runtime, bag.getZone(), encoding);
            if (tainted) zone.taint(context);

            setHashValue(runtime, hash, "zone", zone);
            int offset = TimeZoneConverter.dateZoneToDiff(bag.getZone());
            if (offset != TimeZoneConverter.INVALID_ZONE) setHashValue(runtime, hash, "offset", runtime.newFixnum(offset));
        }

        if (has(bag.getSecFraction())) {
            final RubyInteger secFraction = toRubyInteger(runtime, bag.getSecFraction());
            final RubyFixnum secFractionSize = RubyFixnum.newFixnum(runtime, (long) Math.pow(10, bag.getSecFractionSize()));
            setHashValue(runtime, hash, "sec_fraction",
                    RubyRational.newRationalCanonicalize(context, secFraction, secFractionSize));
        }

        if (bag.has(bag.getSeconds())) {
            if (has(bag.getSecondsSize())) {
                final RubyInteger seconds = toRubyInteger(runtime, bag.getSeconds());
                final RubyFixnum secondsSize = RubyFixnum.newFixnum(runtime, (long) Math.pow(10, bag.getSecondsSize()));
                setHashValue(runtime, hash, "seconds", RubyRational.newRationalCanonicalize(context, seconds, secondsSize));
            } else {
                setHashValue(runtime, hash, "seconds", toRubyInteger(runtime, bag.getSeconds()));
            }
        }
        if (has(bag.getMerid())) {
            setHashValue(runtime, hash, "_merid", runtime.newFixnum(bag.getMerid()));
        }
        if (has(bag.getCent())) {
            setHashValue(runtime, hash, "_cent", RubyBignum.newBignum(runtime, bag.getCent()));
        }
        if (bag.getLeftover() != null) {
            final RubyString leftover = RubyString.newString(runtime, bag.getLeftover(), encoding);
            if (tainted) leftover.taint(context);

            setHashValue(runtime, hash, "leftover", leftover);
        }

        return hash;
    }

    private static RubyInteger toRubyInteger(final Ruby runtime, final Number i) {
        if (i instanceof BigInteger) {
            return RubyBignum.newBignum(runtime, (BigInteger) i);
        }
        return RubyFixnum.newFixnum(runtime, i.longValue());
    }

    private static void setHashValue(final Ruby runtime, final RubyHash hash, final String key, final IRubyObject value) {
        hash.fastASet(RubySymbol.newSymbol(runtime, key), value);
    }

}