ReaderToAscii


1   /*
2   
3      Derby - Class org.apache.derby.impl.jdbc.ReaderToAscii
4   
5      Licensed to the Apache Software Foundation (ASF) under one or more
6      contributor license agreements.  See the NOTICE file distributed with
7      this work for additional information regarding copyright ownership.
8      The ASF licenses this file to you under the Apache License, Version 2.0
9      (the "License"); you may not use this file except in compliance with
10     the License.  You may obtain a copy of the License at
11  
12        http://www.apache.org/licenses/LICENSE-2.0
13  
14     Unless required by applicable law or agreed to in writing, software
15     distributed under the License is distributed on an "AS IS" BASIS,
16     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
17     See the License for the specific language governing permissions and
18     limitations under the License.
19  
20   */
21  
22  package org.apache.derby.impl.jdbc;
23  
24  import java.io.InputStream  ;
25  import java.io.Reader  ;
26  import java.io.IOException  ;
27  import java.sql.SQLException  ;
28  
29  /**
30      ReaderToAscii converts Reader (with characters) to a stream of ASCII characters.
31  */
32  public final class ReaderToAscii extends InputStream  
33  {
34  
35      private final Reader   data;
36      private char[]  conv;
37      private boolean closed;
38  
39      public ReaderToAscii(Reader   data) 
40      {
41          this.data = data;
42          if (!(data instanceof UTF8Reader))
43              conv = new char[256];
44      }
45  
46      public int read() throws IOException  
47      {
48          if (closed)
49              throw new IOException  ();
50  
51          int c = data.read();
52          if (c == -1)
53              return -1;
54  
55          if (c <= 255)
56              return c & 0xFF;
57          else
58              return '?'; // Question mark - out of range character.
59      }
60  
61      public int read(byte[] buf, int off, int len) throws IOException  
62      {
63          if (closed)
64              throw new IOException  ();
65  
66          if (data instanceof UTF8Reader) {
67  
68              return ((UTF8Reader) data).readAsciiInto(buf, off, len);
69          }
70  
71          if (len > conv.length)
72              len = conv.length;
73  
74          len = data.read(conv, 0, len);
75          if (len == -1)
76              return -1;
77  
78          for (int i = 0; i < len; i++) {
79              char c = conv[i];
80  
81              byte cb;
82              if (c <= 255)
83                  cb = (byte) c;
84              else
85                  cb = (byte) '?'; // Question mark - out of range character.
86                  
87              buf[off++] = cb;
88          }
89  
90          return len;
91      }
92  
93      public long skip(long len) throws IOException   {
94          if (closed)
95              throw new IOException  ();
96  
97          return data.skip(len);
98      }
99  
100     public void close() throws IOException  
101     {
102         if (!closed) {
103             closed = true;
104             data.close();
105         }
106     }
107 }
108
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