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1   //
2   //  ========================================================================
3   //  Copyright (c) 1995-2016 Mort Bay Consulting Pty. Ltd.
4   //  ------------------------------------------------------------------------
5   //  All rights reserved. This program and the accompanying materials
6   //  are made available under the terms of the Eclipse Public License v1.0
7   //  and Apache License v2.0 which accompanies this distribution.
8   //
9   //      The Eclipse Public License is available at
10  //      http://www.eclipse.org/legal/epl-v10.html
11  //
12  //      The Apache License v2.0 is available at
13  //      http://www.opensource.org/licenses/apache2.0.php
14  //
15  //  You may elect to redistribute this code under either of these licenses.
16  //  ========================================================================
17  //
18  
19  package org.eclipse.jetty.util;
20  
21  import java.io.BufferedInputStream;
22  import java.io.IOException;
23  import java.io.InputStream;
24  import java.nio.charset.StandardCharsets;
25  
26  /**
27   * ReadLineInputStream
28   *
29   * Read from an input stream, accepting CR/LF, LF or just CR.
30   */
31  public class ReadLineInputStream extends BufferedInputStream
32  {
33      boolean _seenCRLF;
34      boolean _skipLF;
35      
36      public ReadLineInputStream(InputStream in)
37      {
38          super(in);
39      }
40  
41      public ReadLineInputStream(InputStream in, int size)
42      {
43          super(in,size);
44      }
45      
46      public String readLine() throws IOException
47      {
48          mark(buf.length);
49                  
50          while (true)
51          {
52              int b=super.read();
53              
54              if (markpos < 0)
55                  throw new IOException("Buffer size exceeded: no line terminator");
56              
57              if (b==-1)
58              {
59                  int m=markpos;
60                  markpos=-1;
61                  if (pos>m)
62                      return new String(buf,m,pos-m, StandardCharsets.UTF_8);
63  
64                  return null;
65              }
66              
67              if (b=='\r')
68              {
69                  int p=pos;
70                  
71                  // if we have seen CRLF before, hungrily consume LF
72                  if (_seenCRLF && pos<count)
73                  {
74                      if (buf[pos]=='\n')
75                          pos+=1;
76                  }
77                  else
78                      _skipLF=true;
79                  int m=markpos;
80                  markpos=-1;
81                  return new String(buf,m,p-m-1,StandardCharsets.UTF_8);
82              }
83              
84              if (b=='\n')
85              {
86                  if (_skipLF)
87                  {
88                      _skipLF=false;
89                      _seenCRLF=true;
90                      markpos++;
91                      continue;
92                  }
93                  int m=markpos;
94                  markpos=-1;
95                  return new String(buf,m,pos-m-1,StandardCharsets.UTF_8);
96              }
97          }
98      }
99  
100     @Override
101     public synchronized int read() throws IOException
102     {
103         int b = super.read();
104         if (_skipLF)
105         {
106             _skipLF=false;
107             if (_seenCRLF && b=='\n')
108                 b=super.read();
109         }
110         return b;
111     }
112 
113     @Override
114     public synchronized int read(byte[] buf, int off, int len) throws IOException
115     {
116         if (_skipLF && len>0)
117         {
118             _skipLF=false;
119             if (_seenCRLF)
120             {
121                 int b = super.read();
122                 if (b==-1)
123                     return -1;
124                 
125                 if (b!='\n')
126                 {
127                     buf[off]=(byte)(0xff&b);
128                     return 1+super.read(buf,off+1,len-1);
129                 }
130             }
131         }
132         
133         return super.read(buf,off,len);
134     }
135     
136     
137 }