58 lines
1.5 KiB
C#
58 lines
1.5 KiB
C#
// Copyright (c) .NET Foundation. All rights reserved.
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// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
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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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using Microsoft.AspNet.Http;
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using Microsoft.AspNet.Routing;
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namespace InlineConstraintSample.Web.Constraints
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{
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public class IsbnDigitScheme13Constraint : IRouteConstraint
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{
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private static readonly int[] _isbn13Weights = new int[] { 1, 3 };
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public bool Match(
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HttpContext httpContext,
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IRouter route,
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string routeKey,
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IDictionary<string, object> values,
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RouteDirection routeDirection)
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{
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object value;
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if (!values.TryGetValue(routeKey, out value))
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{
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return false;
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}
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var isbnNumber = value as string;
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if (isbnNumber == null
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|| isbnNumber.Length != 13
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|| isbnNumber.Any(n => n < '0' || n > '9'))
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{
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return false;
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}
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var sum = 0;
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Func<char, int> convertToInt = (char n) => n - '0';
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for (int i = 0; i < isbnNumber.Length - 1; ++i)
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{
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sum +=
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convertToInt(isbnNumber[i]) * _isbn13Weights[i % 2];
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}
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var checkSum = 10 - sum % 10;
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if (checkSum == convertToInt(isbnNumber.Last()))
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{
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return true;
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}
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return false;
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}
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}
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} |