mcs/class/System.Net.Http/System.Net.Http.Headers/QualityValue.cs

   1 //
   2 // QualityValue.cs
   3 //
   4 // Authors:
   5 //      Marek Safar  <marek.safar@gmail.com>
   6 //
   7 // Copyright (C) 2011 Xamarin Inc (http://www.xamarin.com)
   8 //
   9 // Permission is hereby granted, free of charge, to any person obtaining
  10 // a copy of this software and associated documentation files (the
  11 // "Software"), to deal in the Software without restriction, including
  12 // without limitation the rights to use, copy, modify, merge, publish,
  13 // distribute, sublicense, and/or sell copies of the Software, and to
  14 // permit persons to whom the Software is furnished to do so, subject to
  15 // the following conditions:
  16 //
  17 // The above copyright notice and this permission notice shall be
  18 // included in all copies or substantial portions of the Software.
  19 //
  20 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  21 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  22 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  23 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  24 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  25 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  26 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  27 //
  28
  29 using System.Globalization;
  30 using System.Collections.Generic;
  31
  32 namespace System.Net.Http.Headers
  33 {
  34         static class QualityValue
  35         {
  36                 public static double? GetValue (List<NameValueHeaderValue> parameters)
  37                 {
  38                         if (parameters == null)
  39                                 return null;
  40
  41                         var found = parameters.Find (l => string.Equals (l.Name, "q", StringComparison.OrdinalIgnoreCase));
  42                         if (found == null)
  43                                 return null;
  44
  45                         double value;
  46                         if (!double.TryParse (found.Value, NumberStyles.Number, NumberFormatInfo.InvariantInfo, out value))
  47                                 return null;
  48
  49                         return value;
  50                 }
  51
  52                 public static void SetValue (ref List<NameValueHeaderValue> parameters, double? value)
  53                 {
  54                         if (value < 0 || value > 1)
  55                                 throw new ArgumentOutOfRangeException ("Quality");
  56
  57                         if (parameters == null)
  58                                 parameters = new List<NameValueHeaderValue> ();
  59
  60                         parameters.SetValue ("q", value == null ? null : value.Value.ToString (NumberFormatInfo.InvariantInfo));
  61                 }
  62         }
  63 }