87 lines
2.8 KiB
C#
87 lines
2.8 KiB
C#
namespace System.Web.ModelBinding {
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using System;
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using System.Collections.Generic;
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using System.Linq;
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/// <summary>
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/// This is a container for prefix values. It normalizes all the values into dotted-form and then stores
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/// them in a sorted array. All queries for prefixes are also normalized to dotted-form, and searches
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/// for ContainsPrefix are done with a binary search.
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/// </summary>
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internal sealed class PrefixContainer {
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private readonly string[] _sortedValues;
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internal PrefixContainer(IEnumerable<string> values) {
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if (values == null) {
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throw new ArgumentNullException("values");
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}
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_sortedValues = values.Where(val => val != null).ToArray();
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Array.Sort(_sortedValues, StringComparer.OrdinalIgnoreCase);
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}
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internal bool ContainsPrefix(string prefix) {
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if (prefix == null) {
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throw new ArgumentNullException("prefix");
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}
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if (prefix.Length == 0) {
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return _sortedValues.Length > 0; // only match empty string when we have some value
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}
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return Array.BinarySearch(_sortedValues, prefix, new PrefixComparer(prefix)) > -1;
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}
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internal static bool IsPrefixMatch(string prefix, string testString) {
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if (testString == null) {
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return false;
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}
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if (prefix.Length == 0) {
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return true; // shortcut - non-null testString matches empty prefix
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}
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if (prefix.Length > testString.Length) {
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return false; // not long enough
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}
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if (!testString.StartsWith(prefix, StringComparison.OrdinalIgnoreCase)) {
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return false; // prefix doesn't match
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}
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if (testString.Length == prefix.Length) {
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return true; // exact match
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}
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// invariant: testString.Length > prefix.Length
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switch (testString[prefix.Length]) {
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case '.':
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case '[':
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return true; // known delimiters
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default:
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return false; // not known delimiter
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}
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}
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private sealed class PrefixComparer : IComparer<String> {
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private string _prefix;
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public PrefixComparer(string prefix) {
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_prefix = prefix;
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}
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public int Compare(string x, string y) {
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string testString = Object.ReferenceEquals(x, _prefix) ? y : x;
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if (IsPrefixMatch(_prefix, testString)) {
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return 0;
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}
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return StringComparer.OrdinalIgnoreCase.Compare(x, y);
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}
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}
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}
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}
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