nweiz@google.com
22d2778e00
This is just the first step; future CLs will add support for the new API to various packages currently using the old one. BUG=19930 R=sigmund@google.com Review URL: https://codereview.chromium.org//381363002 git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@38360 260f80e4-7a28-3924-810f-c04153c831b5
40 lines
1.3 KiB
Dart
40 lines
1.3 KiB
Dart
// Copyright (c) 2014, the Dart project authors. Please see the AUTHORS file
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// for details. All rights reserved. Use of this source code is governed by a
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// BSD-style license that can be found in the LICENSE file.
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library source_span.utils;
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/// Returns the minimum of [obj1] and [obj2] according to
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/// [Comparable.compareTo].
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Comparable min(Comparable obj1, Comparable obj2) =>
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obj1.compareTo(obj2) > 0 ? obj2 : obj1;
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/// Returns the maximum of [obj1] and [obj2] according to
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/// [Comparable.compareTo].
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Comparable max(Comparable obj1, Comparable obj2) =>
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obj1.compareTo(obj2) > 0 ? obj1 : obj2;
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/// Find the first entry in a sorted [list] that matches a monotonic predicate.
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///
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/// Given a result `n`, that all items before `n` will not match, `n` matches,
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/// and all items after `n` match too. The result is -1 when there are no
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/// items, 0 when all items match, and list.length when none does.
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int binarySearch(List list, bool matches(item)) {
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if (list.length == 0) return -1;
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if (matches(list.first)) return 0;
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if (!matches(list.last)) return list.length;
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int min = 0;
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int max = list.length - 1;
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while (min < max) {
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var half = min + ((max - min) ~/ 2);
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if (matches(list[half])) {
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max = half;
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} else {
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min = half + 1;
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}
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}
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return max;
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}
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