Constructs a new DateTime instance based on formattedString.
Throws a FormatException if the input cannot be parsed.
The function parses a subset of ISO 8601 which includes the subset accepted by RFC 3339.
The accepted inputs are currently:
- characters.
Examples: "19700101", "-0004-12-24", "81030-04-01".T or a space.
The time part is a two digit hour,
then optionally a two digit minutes value,
then optionally a two digit seconds value, and
then optionally a '.' or ',' followed by a one-to-six digit second fraction.
The minutes and seconds may be separated from the previous parts by a
':'.
Examples: "12", "12:30:24.124", "12:30:24,124", "123010.50".This includes the output of both toString and toIso8601String, which
will be parsed back into a DateTime object with the same time as the
original.
The result is always in either local time or UTC. If a time zone offset other than UTC is specified, the time is converted to the equivalent UTC time.
Examples of accepted strings:
"2012-02-27 13:27:00""2012-02-27 13:27:00.123456z""2012-02-27 13:27:00,123456z""20120227 13:27:00""20120227T132700""20120227""+20120227""2012-02-27T14Z""2012-02-27T14+00:00""-123450101 00:00:00 Z": in the year -12345."2002-02-27T14:00:00-0500": Same as "2002-02-27T19:00:00Z"// TODO(lrn): restrict incorrect values like 2003-02-29T50:70:80.
// Or not, that may be a breaking change.
static DateTime parse(String formattedString) {
var re = _parseFormat;
Match match = re.firstMatch(formattedString);
if (match != null) {
int parseIntOrZero(String matched) {
if (matched == null) return 0;
return int.parse(matched);
}
// Parses fractional second digits of '.(\d{1,6})' into the combined
// microseconds.
int parseMilliAndMicroseconds(String matched) {
if (matched == null) return 0;
int length = matched.length;
assert(length >= 1);
assert(length <= 6);
int result = 0;
for (int i = 0; i < 6; i++) {
result *= 10;
if (i < matched.length) {
result += matched.codeUnitAt(i) ^ 0x30;
}
}
return result;
}
int years = int.parse(match[1]);
int month = int.parse(match[2]);
int day = int.parse(match[3]);
int hour = parseIntOrZero(match[4]);
int minute = parseIntOrZero(match[5]);
int second = parseIntOrZero(match[6]);
bool addOneMillisecond = false;
int milliAndMicroseconds = parseMilliAndMicroseconds(match[7]);
int millisecond =
milliAndMicroseconds ~/ Duration.microsecondsPerMillisecond;
int microsecond =
milliAndMicroseconds.remainder(Duration.microsecondsPerMillisecond);
bool isUtc = false;
if (match[8] != null) {
// timezone part
isUtc = true;
if (match[9] != null) {
// timezone other than 'Z' and 'z'.
int sign = (match[9] == '-') ? -1 : 1;
int hourDifference = int.parse(match[10]);
int minuteDifference = parseIntOrZero(match[11]);
minuteDifference += 60 * hourDifference;
minute -= sign * minuteDifference;
}
}
int value = _brokenDownDateToValue(years, month, day, hour, minute,
second, millisecond, microsecond, isUtc);
if (value == null) {
throw new FormatException("Time out of range", formattedString);
}
return new DateTime._withValue(value, isUtc: isUtc);
} else {
throw new FormatException("Invalid date format", formattedString);
}
}