Util/PullingReader.cs

   1 //
   2 // PullingReader.cs
   3 //
   4 // Copyright (C) 2004 Novell, Inc.
   5 //
   6
   7 //
   8 // Permission is hereby granted, free of charge, to any person obtaining a copy
   9 // of this software and associated documentation files (the "Software"), to deal
  10 // in the Software without restriction, including without limitation the rights
  11 // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  12 // copies of the Software, and to permit persons to whom the Software is
  13 // furnished to do so, subject to the following conditions:
  14 //
  15 // The above copyright notice and this permission notice shall be included in all
  16 // copies or substantial portions of the Software.
  17 //
  18 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  19 // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  20 // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  21 // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  22 // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  23 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  24 // SOFTWARE.
  25 //
  26
  27 using System;
  28 using System.Collections;
  29 using System.IO;
  30 using System.Text;
  31
  32 namespace Beagle.Util {
  33
  34         public class PullingReader : TextReader {
  35
  36                 private string identifier;
  37
  38                 public string Identifier {
  39                         get { return identifier; }
  40                         set { identifier = value; }
  41                 }
  42
  43                 //////////////////////////
  44
  45                 public delegate bool Pull (StringBuilder buffer);
  46
  47                 Pull pull;
  48                 StringBuilder pullBuffer = new StringBuilder ();
  49                 bool done = false;
  50
  51                 public PullingReader (Pull _pull) : base ()
  52                 {
  53                         pull = _pull;
  54                 }
  55
  56                 private void DoPull (int neededSize)
  57                 {
  58                         while (! done && pullBuffer.Length < neededSize) {
  59                                 try {
  60                                         done = ! pull (pullBuffer);
  61                                 } catch (Exception e) {
  62                                         Logger.Log.Debug ("Caught exception pulling text from {0}", pull);
  63                                         Logger.Log.Debug (e);
  64                                 }
  65                         }
  66                 }
  67
  68                 public override void Close ()
  69                 {
  70
  71                 }
  72
  73                 public override int Peek ()
  74                 {
  75                         DoPull (1);
  76                         return done ? -1 : (int) pullBuffer [0];
  77                 }
  78
  79                 public override int Read ()
  80                 {
  81                         DoPull (1);
  82                         if (done)
  83                                 return -1;
  84                         int x = (int) pullBuffer [0];
  85                         pullBuffer.Remove (0, 1);
  86                         return x;
  87                 }
  88
  89                 public override int Read (char[] buffer, int index, int count)
  90                 {
  91                         DoPull (count);
  92                         if (done && pullBuffer.Length < count)
  93                                 count = pullBuffer.Length;
  94
  95                         for (int i = 0; i < count; ++i)
  96                                 buffer [index + i] = pullBuffer [i];
  97                         pullBuffer.Remove (0, count);
  98
  99                         return count;
 100                 }
 101
 102                 public override int ReadBlock (char[] buffer, int index, int count)
 103                 {
 104                         return Read (buffer, index, count);
 105                 }
 106
 107                 public override string ReadLine ()
 108                 {
 109                         int i = 0;
 110
 111                         DoPull (1);
 112
 113                         if (done)
 114                                 return null;
 115
 116                         while (true) {
 117
 118                                 while (i < pullBuffer.Length) {
 119                                         if (pullBuffer [i] == '\n') {
 120                                                 string foo = pullBuffer.ToString (0, i);
 121                                                 pullBuffer.Remove (0, i+1);
 122                                                 return foo;
 123                                         }
 124                                         ++i;
 125                                 }
 126
 127                                 // If there is nothing else to pull, just return everything
 128                                 // in our buffer.
 129                                 if (done) {
 130                                         string str = pullBuffer.ToString ();
 131                                         pullBuffer.Length = 0;
 132                                         return str;
 133                                 }
 134
 135                                 DoPull (2 * pullBuffer.Length);
 136                         }
 137                 }
 138
 139                 public override string ReadToEnd ()
 140                 {
 141                         while (! done)
 142                                 DoPull (2 * pullBuffer.Length);
 143
 144                         string str = pullBuffer.ToString ();
 145                         pullBuffer.Length = 0;
 146                         return str;
 147                 }
 148
 149
 150
 151         }
 152 }