68 lines
2.2 KiB
C#
68 lines
2.2 KiB
C#
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using System;
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using System.Collections.Generic;
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namespace Swan {
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/// <summary>
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/// Extension methods.
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/// </summary>
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public static partial class Extensions {
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/// <summary>
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/// Gets the value if exists or default.
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/// </summary>
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/// <typeparam name="TKey">The type of the key.</typeparam>
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/// <typeparam name="TValue">The type of the value.</typeparam>
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/// <param name="dict">The dictionary.</param>
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/// <param name="key">The key.</param>
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/// <param name="defaultValue">The default value.</param>
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/// <returns>
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/// The value of the provided key or default.
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/// </returns>
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/// <exception cref="ArgumentNullException">dict.</exception>
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public static TValue GetValueOrDefault<TKey, TValue>(this IDictionary<TKey, TValue> dict, TKey key, TValue defaultValue = default) {
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if(dict == null) {
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throw new ArgumentNullException(nameof(dict));
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}
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return dict.ContainsKey(key) ? dict[key] : defaultValue;
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}
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/// <summary>
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/// Adds a key/value pair to the Dictionary if the key does not already exist.
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/// If the value is null, the key will not be updated.
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/// Based on <c>ConcurrentDictionary.GetOrAdd</c> method.
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/// </summary>
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/// <typeparam name="TKey">The type of the key.</typeparam>
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/// <typeparam name="TValue">The type of the value.</typeparam>
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/// <param name="dict">The dictionary.</param>
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/// <param name="key">The key.</param>
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/// <param name="valueFactory">The value factory.</param>
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/// <returns>
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/// The value for the key.
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/// </returns>
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/// <exception cref="ArgumentNullException">
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/// dict
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/// or
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/// valueFactory.
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/// </exception>
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public static TValue GetOrAdd<TKey, TValue>(this IDictionary<TKey, TValue> dict, TKey key, Func<TKey, TValue> valueFactory) {
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if(dict == null) {
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throw new ArgumentNullException(nameof(dict));
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}
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if(valueFactory == null) {
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throw new ArgumentNullException(nameof(valueFactory));
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}
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if(!dict.ContainsKey(key)) {
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TValue value = valueFactory(key);
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if(Equals(value, default)) {
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return default;
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}
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dict[key] = value;
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}
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return dict[key];
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}
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}
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}
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