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// Copyright 2013 The Closure Library Authors. All Rights Reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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//      http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS-IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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/**
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 * @fileoverview Contains helper functions for performing locale-sensitive
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 *     collation.
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 */
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goog.provide('goog.i18n.collation');
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/**
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 * Returns the comparator for a locale. If a locale is not explicitly specified,
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 * a comparator for the user's locale will be returned. Note that if the browser
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 * does not support locale-sensitive string comparisons, the comparator returned
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 * will be a simple codepoint comparator.
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 *
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 * @param {string=} opt_locale the locale that the comparator is used for.
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 * @param {{usage: (string|undefined), localeMatcher: (string|undefined),
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 *     sensitivity: (string|undefined), ignorePunctuation: (boolean|undefined),
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 *     numeric: (boolean|undefined), caseFirst: (string|undefined)}=}
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 *         opt_options the optional set of options for use with the native
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 *         collator.
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 * @return {function(string, string): number} The locale-specific comparator.
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 */
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goog.i18n.collation.createComparator = function(opt_locale, opt_options) {
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  // See http://code.google.com/p/v8-i18n.
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  if (goog.i18n.collation.hasNativeComparator()) {
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    var intl = goog.global.Intl;
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    return new intl.Collator([opt_locale || goog.LOCALE], opt_options || {})
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        .compare;
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  } else {
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    return function(arg1, arg2) { return arg1.localeCompare(arg2); };
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  }
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};
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/**
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 * Returns true if a locale-sensitive comparator is available for a locale. If
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 * a locale is not explicitly specified, the user's locale is used instead.
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 *
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 * @param {string=} opt_locale The locale to be checked.
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 * @return {boolean} Whether there is a locale-sensitive comparator available
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 *     for the locale.
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 */
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goog.i18n.collation.hasNativeComparator = function(opt_locale) {
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  var intl = goog.global.Intl;
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  return !!(intl && intl.Collator);
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};
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