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namespace System.Web.Mvc {
using System;
using System.Collections.Generic;
using System.Linq;
internal static class ValueProviderUtil {
// Given "foo.bar[baz].quux", this method will return:
// - "foo.bar[baz].quux"
// - "foo.bar[baz]"
// - "foo.bar"
// - "foo"
public static IEnumerable<string> GetPrefixes(string key) {
yield return key;
for (int i = key.Length - 1; i >= 0; i--) {
switch (key[i]) {
case '.':
case '[':
yield return key.Substring(0, i);
break;
}
}
}
public static bool CollectionContainsPrefix(IEnumerable<string> collection, string prefix) {
foreach (string key in collection) {
if (key != null) {
if (prefix.Length == 0) {
return true; // shortcut - non-null key matches empty prefix
}
if (key.StartsWith(prefix, StringComparison.OrdinalIgnoreCase)) {
if (key.Length == prefix.Length) {
return true; // exact match
}
else {
switch (key[prefix.Length]) {
case '.': // known separator characters
case '[':
return true;
}
}
}
}
}
return false; // nothing found
}
}
}
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