Roll Observatory packages and add a roll script

charted/lib/locale/format.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.locale.format;
-
-import 'dart:math' as math;
-import 'package:intl/intl.dart';
-import 'package:charted/locale/locale.dart';
-import 'package:charted/core/utils.dart';
-
-part 'format/number_format.dart';
-part 'format/time_format.dart';
-
-typedef String NumberFormatFunction(num x, [int precision]);
-
-/**
- * Returns a new format function with the given string specifier.
- * The format specifier is modeled after Python 3.1's built-in format
- * specification mini-language.
- *
- * The general form of a specifier is:
- * [​[fill]align][sign][symbol][0][width][,][.precision][type]
- *
- * @see <a href="http://docs.python.org/release/3.1.3/library/string.html#formatspec">Python format specification mini-language</a>
- */
-FormatFunction format(String specifier, [Locale locale = null]) {
-  if (locale == null) {
-    locale = new EnUsLocale();
-  }
-  return locale.numberFormat.format(specifier);
-}
-
-
-/*
- * Class for computing the SI format prefix for the given value.
- */
-class FormatPrefix {
-  // SI scale units in increments of 1000.
-  static const List unitPrefixes = const
-      ["y","z","a","f","p","n","µ","m","","k","M","G","T","P","E","Z","Y"];
-
-  Function _scale;
-  String _symbol;
-
-  FormatPrefix(num value, [int precision = 0]) {
-    var i = 0;
-    if (value < 0) {
-      value *= -1;
-    }
-    if (precision > 0) {
-      value = _roundToPrecision(value, _formatPrecision(value, precision));
-    }
-
-    // Determining SI scale of the value in increment of 1000.
-    i = 1 + (1e-12 + math.log(value) / math.LN10).floor();
-    i = math.max(-24, math.min(24,
-        ((i - 1) / 3).floor() * 3));
-    i = 8 + (i / 3).floor();
-
-    // Sets the scale and symbol of the value.
-    var k = math.pow(10, (8 - i).abs() * 3);
-    _scale = i > 8 ? (d) => d / k : (d) => d * k;
-    _symbol = unitPrefixes[i];
-  }
-
-  _formatPrecision(num x, num p) {
-    return p - (x != 0 ? (math.log(x) / math.LN10).ceil() : 1);
-  }
-
-  /** Returns the value of x rounded to the nth digit. */
-  _roundToPrecision(num x, num n) {
-    return n != 0 ?
-        (x * (n = math.pow(10, n))).round() / n : x.round();
-  }
-
-  /** Returns the SI prefix for the value. */
-  get symbol => _symbol;
-
-  /** Returns the scale for the value corresponding to the SI prefix. */
-  get scale => _scale;
-}