HsqlByteArrayInputStream


1   /* Copyright (c) 2001-2005, The HSQL Development Group
2    * All rights reserved.
3    *
4    * Redistribution and use in source and binary forms, with or without
5    * modification, are permitted provided that the following conditions are met:
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7    * Redistributions of source code must retain the above copyright notice, this
8    * list of conditions and the following disclaimer.
9    *
10   * Redistributions in binary form must reproduce the above copyright notice,
11   * this list of conditions and the following disclaimer in the documentation
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14   * Neither the name of the HSQL Development Group nor the names of its
15   * contributors may be used to endorse or promote products derived from this
16   * software without specific prior written permission.
17   *
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20   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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22   * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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29   */
30  
31  
32  package org.hsqldb.lib;
33  
34  import java.io.DataInput  ;
35  import java.io.EOFException  ;
36  import java.io.IOException  ;
37  import java.io.InputStream  ;
38  
39  /**
40   * This class is a replacement for both java.io.ByteArrayInputStream
41   * (without synchronization) and java.io.DataInputStream
42   *
43   * @author fredt@users
44   * @version 1.7.2
45   * @since 1.7.2
46   */
47  public class HsqlByteArrayInputStream extends InputStream  
48  implements DataInput   {
49  
50      protected byte[] buf;
51      protected int    pos;
52      protected int    mark = 0;
53      protected int    count;
54  
55      public HsqlByteArrayInputStream(byte[] buf) {
56  
57          this.buf   = buf;
58          this.pos   = 0;
59          this.count = buf.length;
60      }
61  
62      public HsqlByteArrayInputStream(byte[] buf, int offset, int length) {
63  
64          this.buf   = buf;
65          this.pos   = offset;
66          this.count = Math.min(offset + length, buf.length);
67          this.mark  = offset;
68      }
69  
70      // methods that implement java.io.DataInput
71      public final void readFully(byte[] b) throws IOException   {
72          readFully(b, 0, b.length);
73      }
74  
75      public final void readFully(byte[] b, int off,
76                                  int len) throws IOException   {
77  
78          if (len < 0) {
79              throw new IndexOutOfBoundsException  ();
80          }
81  
82          int n = 0;
83  
84          while (n < len) {
85              int count = read(b, off + n, len - n);
86  
87              if (count < 0) {
88                  throw new EOFException  ();
89              }
90  
91              n += count;
92          }
93      }
94  
95      public final boolean readBoolean() throws IOException   {
96  
97          int ch = read();
98  
99          if (ch < 0) {
100             throw new EOFException  ();
101         }
102 
103         return (ch != 0);
104     }
105 
106     public final byte readByte() throws IOException   {
107 
108         int ch = read();
109 
110         if (ch < 0) {
111             throw new EOFException  ();
112         }
113 
114         return (byte) ch;
115     }
116 
117     public final int readUnsignedByte() throws IOException   {
118 
119         int ch = read();
120 
121         if (ch < 0) {
122             throw new EOFException  ();
123         }
124 
125         return ch;
126     }
127 
128     public short readShort() throws IOException   {
129 
130         if (count - pos < 2) {
131             pos = count;
132 
133             throw new EOFException  ();
134         }
135 
136         int ch1 = buf[pos++] & 0xff;
137         int ch2 = buf[pos++] & 0xff;
138 
139         return (short) ((ch1 << 8) + (ch2));
140     }
141 
142     public final int readUnsignedShort() throws IOException   {
143 
144         int ch1 = read();
145         int ch2 = read();
146 
147         if ((ch1 | ch2) < 0) {
148             throw new EOFException  ();
149         }
150 
151         return (ch1 << 8) + (ch2);
152     }
153 
154     public final char readChar() throws IOException   {
155 
156         int ch1 = read();
157         int ch2 = read();
158 
159         if ((ch1 | ch2) < 0) {
160             throw new EOFException  ();
161         }
162 
163         return (char) ((ch1 << 8) + (ch2));
164     }
165 
166     public int readInt() throws IOException   {
167 
168         if (count - pos < 4) {
169             pos = count;
170 
171             throw new EOFException  ();
172         }
173 
174         int ch1 = buf[pos++] & 0xff;
175         int ch2 = buf[pos++] & 0xff;
176         int ch3 = buf[pos++] & 0xff;
177         int ch4 = buf[pos++] & 0xff;
178 
179         return ((ch1 << 24) + (ch2 << 16) + (ch3 << 8) + (ch4));
180     }
181 
182     public final long readLong() throws IOException   {
183         return (((long) readInt()) << 32)
184                + (((long) readInt()) & 0xffffffffL);
185     }
186 
187     public final float readFloat() throws IOException   {
188         return Float.intBitsToFloat(readInt());
189     }
190 
191     public final double readDouble() throws IOException   {
192         return Double.longBitsToDouble(readLong());
193     }
194 
195     public int skipBytes(int n) throws IOException   {
196         return (int) skip(n);
197     }
198 
199     public String   readLine() throws IOException   {
200 
201         /** @todo: this will probably be useful */
202         throw new java.lang.RuntimeException  ("not implemented.");
203     }
204 
205     public String   readUTF() throws IOException   {
206 
207         int bytecount = readUnsignedShort();
208 
209         if (pos + bytecount >= count) {
210             throw new EOFException  ();
211         }
212 
213         String   result = StringConverter.readUTF(buf, pos, bytecount);
214 
215         pos += bytecount;
216 
217         return result;
218     }
219 
220 // methods that extend java.io.InputStream
221     public int read() {
222         return (pos < count) ? (buf[pos++] & 0xff)
223                              : -1;
224     }
225 
226     public int read(byte[] b, int off, int len) {
227 
228         if (pos >= count) {
229             return -1;
230         }
231 
232         if (pos + len > count) {
233             len = count - pos;
234         }
235 
236         if (len <= 0) {
237             return 0;
238         }
239 
240         System.arraycopy(buf, pos, b, off, len);
241 
242         pos += len;
243 
244         return len;
245     }
246 
247     public long skip(long n) {
248 
249         if (pos + n > count) {
250             n = count - pos;
251         }
252 
253         if (n < 0) {
254             return 0;
255         }
256 
257         pos += n;
258 
259         return n;
260     }
261 
262     public int available() {
263         return count - pos;
264     }
265 
266     public boolean markSupported() {
267         return true;
268     }
269 
270     public void mark(int readAheadLimit) {
271         mark = pos;
272     }
273 
274     public void reset() {
275         pos = mark;
276     }
277 
278     public void close() throws IOException   {}
279 }
280
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