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

   1 //
   2 // CollectionParser.cs
   3 //
   4 // Authors:
   5 //      Marek Safar  <marek.safar@gmail.com>
   6 //
   7 // Copyright (C) 2014 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.Collections.Generic;
  30
  31 namespace System.Net.Http.Headers
  32 {
  33         delegate bool ElementTryParser<T> (Lexer lexer, out T parsedValue, out Token token);
  34
  35         static class CollectionParser
  36         {
  37                 public static bool TryParse<T> (string input, int minimalCount, ElementTryParser<T> parser, out List<T> result) where T : class
  38                 {
  39                         var lexer = new Lexer (input);
  40                         result = new List<T> ();
  41
  42                         while (true) {
  43                                 Token token;
  44                                 T parsedValue;
  45                                 if (!parser (lexer, out parsedValue, out token))
  46                                         return false;
  47
  48                                 if (parsedValue != null)
  49                                         result.Add (parsedValue);
  50
  51                                 if (token == Token.Type.SeparatorComma)
  52                                         continue;
  53
  54                                 if (token == Token.Type.End) {
  55                                         if (minimalCount > result.Count) {
  56                                                 result = null;
  57                                                 return false;
  58                                         }
  59
  60                                         return true;
  61                                 }
  62
  63                                 result = null;
  64                                 return false;
  65                         }
  66                 }
  67
  68                 public static bool TryParse (string input, int minimalCount, out List<string> result)
  69                 {
  70                         return TryParse (input, minimalCount, TryParseStringElement, out result);
  71                 }
  72
  73                 public static bool TryParseRepetition (string input, int minimalCount, out List<string> result)
  74                 {
  75                         return TryParseRepetition (input, minimalCount, TryParseStringElement, out result);
  76                 }
  77
  78                 static bool TryParseStringElement (Lexer lexer, out string parsedValue, out Token t)
  79                 {
  80                         t = lexer.Scan ();
  81                         if (t == Token.Type.Token) {
  82                                 parsedValue = lexer.GetStringValue (t);
  83                                 if (parsedValue.Length == 0)
  84                                         parsedValue = null;
  85
  86                                 t = lexer.Scan ();
  87                         } else {
  88                                 parsedValue = null;
  89                         }
  90
  91                         return true;
  92                 }
  93
  94                 public static bool TryParseRepetition<T> (string input, int minimalCount, ElementTryParser<T> parser, out List<T> result) where T : class
  95                 {
  96                         var lexer = new Lexer (input);
  97                         result = new List<T> ();
  98
  99                         while (true) {
 100                                 Token token;
 101                                 T parsedValue;
 102                                 if (!parser (lexer, out parsedValue, out token))
 103                                         return false;
 104
 105                                 if (parsedValue != null)
 106                                         result.Add (parsedValue);
 107
 108                                 if (token == Token.Type.End) {
 109                                         if (minimalCount > result.Count)
 110                                                 return false;
 111
 112                                         return true;
 113                                 }
 114                         }
 115                 }
 116         }
 117 }