Roll Observatory packages and add a roll script

charted/lib/core/time_interval.dart

-//
-// Copyright 2014 Google Inc. All rights reserved.
-//
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file or at
-// https://developers.google.com/open-source/licenses/bsd
-//
-
-library charted.core.time_intervals;
-
-typedef DateTime TimeFloorFunction(DateTime val);
-typedef DateTime TimeStepFunction(DateTime val, int offset);
-typedef int TimeToNumberFunction(DateTime val);
-
-class TimeInterval {
-  TimeFloorFunction _floor;
-  TimeStepFunction _step;
-  TimeToNumberFunction _number;
-
-  TimeInterval(this._floor, this._step, this._number);
-
-  DateTime floor(dynamic date) {
-    assert(date is int || date is DateTime);
-    if (date is int) {
-      date = new DateTime.fromMillisecondsSinceEpoch(date) ;
-    }
-    return _floor(date);
-  }
-
-  DateTime round(dynamic date) {
-    DateTime d0 = floor(date),
-             d1 = offset(d0, 1);
-    int ms = date is int ? date : date.millisecondsSinceEpoch;
-    return (ms - d0.millisecondsSinceEpoch < d1.millisecondsSinceEpoch - ms)
-        ? d0
-        : d1;
-  }
-
-  DateTime ceil(dynamic date) => offset(floor(date), 1);
-
-  DateTime offset(DateTime date, int k) => _step(date, k);
-
-  Iterable<DateTime> range(dynamic t0, dynamic t1, int dt) {
-    assert(t0 is int || t0 is DateTime);
-    assert(t1 is int || t1 is DateTime);
-
-    List<DateTime> values = [];
-    if (t1 is int) {
-      t1 = new DateTime.fromMillisecondsSinceEpoch(t1);
-    }
-
-    DateTime time = ceil(t0);
-    if (dt > 1) {
-      while (time.isBefore(t1)) {
-        if ((_number(time) % dt) == 0) {
-          values.add(
-              new DateTime.fromMillisecondsSinceEpoch(
-                  time.millisecondsSinceEpoch));
-        }
-        time = _step(time, 1);
-      }
-    }
-    else {
-      while (time.isBefore(t1)) {
-        values.add(
-            new DateTime.fromMillisecondsSinceEpoch(
-                time.millisecondsSinceEpoch));
-        time = _step(time, 1);
-      }
-    }
-    return values;
-  }
-
-  static TimeInterval second = new TimeInterval(
-      (DateTime date) =>
-          new DateTime.fromMillisecondsSinceEpoch(
-              (date.millisecondsSinceEpoch ~/ 1000) * 1000),
-      (DateTime date, int offset) =>
-          date = new DateTime.fromMillisecondsSinceEpoch(
-              date.millisecondsSinceEpoch + offset * 1000),
-      (DateTime date) => date.second);
-
-  static TimeInterval minute = new TimeInterval(
-      (DateTime date) =>
-          new DateTime.fromMillisecondsSinceEpoch(
-              (date.millisecondsSinceEpoch ~/ 60000) * 60000),
-      (DateTime date, int offset) =>
-          date = new DateTime.fromMillisecondsSinceEpoch(
-              date.millisecondsSinceEpoch + offset * 60000),
-      (DateTime date) => date.minute);
-
-  static TimeInterval hour = new TimeInterval(
-      (DateTime date) =>
-          new DateTime.fromMillisecondsSinceEpoch(
-              (date.millisecondsSinceEpoch ~/ 3600000) * 3600000),
-      (DateTime date, int offset) =>
-          date = new DateTime.fromMillisecondsSinceEpoch(
-              date.millisecondsSinceEpoch + offset * 3600000),
-      (DateTime date) => date.hour);
-
-  static TimeInterval day = new TimeInterval(
-      (DateTime date) =>
-          new DateTime(date.year, date.month, date.day),
-      (DateTime date, int offset) =>
-          new DateTime(date.year, date.month, date.day + offset,
-              date.hour, date.minute, date.second, date.millisecond),
-      (DateTime date) => date.day - 1);
-
-  static TimeInterval week = new TimeInterval(
-      (DateTime date) =>
-          new DateTime(date.year, date.month, date.day - (date.weekday % 7)),
-      (DateTime date, int offset) =>
-          new DateTime(date.year, date.month, date.day + offset * 7,
-              date.hour, date.minute, date.second, date.millisecond ),
-      (DateTime date) {
-        var day = year.floor(date).day;
-        return (dayOfYear(date) +  day % 7) ~/ 7;
-      });
-
-  static TimeInterval month = new TimeInterval(
-      (DateTime date) => new DateTime(date.year, date.month, 1),
-      (DateTime date, num offset) =>
-          new DateTime(date.year, date.month + offset, date.day,
-              date.hour, date.minute, date.second, date.millisecond),
-      (DateTime date) => date.month - 1);
-
-  static TimeInterval year = new TimeInterval(
-      (DateTime date) => new DateTime(date.year),
-      (DateTime date, num offset) =>
-          new DateTime(date.year + offset, date.month, date.day,
-              date.hour, date.minute, date.second, date.millisecond),
-      (DateTime date) => date.year);
-
-  static int dayOfYear(DateTime date) =>
-      date.difference(year.floor(date)).inDays;
-}