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1
22 package org.jboss.mq.il.uil2.msgs;
23
24
28 public class DynCircularBuffer
29 {
30 byte[] buffer;
31 int pos;
32 int end;
33 boolean isFull;
34
35
36 public DynCircularBuffer()
37 {
38 this(1024);
39 }
40 public DynCircularBuffer(int capacity)
41 {
42 buffer = new byte[capacity];
43 pos = 0;
44 end = 0;
45 }
46
47 public synchronized void clear()
48 {
49 pos = 0;
50 end = 0;
51 isFull = false;
52 }
53
54 public synchronized void fill(byte[] data)
55 {
56 fill(data, data.length);
57 }
58 public synchronized void fill(byte[] data, int length)
59 {
60 int freeSpace = getFreeSpace();
61 int currentLength = getSize();
62 if( freeSpace < length )
63 {
64 int newSize = buffer.length + length - freeSpace;
65 byte[] tmp = new byte[newSize];
66 for(int i = 0; i < currentLength; i ++)
67 {
68 tmp[i] = buffer[pos];
69 pos ++;
70 if( pos == buffer.length )
71 pos = 0;
72 }
73 buffer = tmp;
74 pos = 0;
75 end = currentLength;
76 }
77 for(int i = 0; i < length; i ++)
79 {
80 buffer[end] = data[i];
81 end ++;
82 if( end == buffer.length )
83 end = 0;
84 }
85 if( end == pos )
86 isFull = true;
87 }
88
89 public synchronized int get()
90 {
91 if( pos == end && isFull == false )
92 return -1;
93
94 int b = buffer[pos] & 0xff;
95 pos ++;
96 if( pos == buffer.length )
97 pos = 0;
98 isFull = false;
99 return b;
100 }
101
102 public synchronized int get(byte b[], int off, int length)
103 {
104 if( pos == end && isFull == false )
105 return -1;
106
107 int getSize = Math.min(getSize(), length);
108 for(int i = 0; i < getSize; i ++)
109 {
110 b[off + i] = buffer[pos];
111 pos ++;
112 if( pos == buffer.length )
113 pos = 0;
114 }
115 isFull = isFull ? getSize == 0 : false;
116 return getSize;
117 }
118
119
121 public synchronized int getSize()
122 {
123 int length = buffer.length - getFreeSpace();
124 return length;
125 }
126
128 public synchronized int getFreeSpace()
129 {
130 int available = 0;
131 if( pos == end )
132 {
133 if( isFull == true )
134 available = 0;
135 else
136 available = buffer.length;
137 }
138 else if( pos < end )
139 available = buffer.length - end + pos;
140 else
141 available = pos - end;
142 return available;
143 }
144
145
147 public static void main(String  [] args) throws Exception
148 {
149 DynCircularBuffer dcb = new DynCircularBuffer(16);
150 if( dcb.getFreeSpace() != 16 )
151 throw new IllegalStateException ("dcb.getFreeSpace() != 16");
152 if( dcb.getSize() != 0 )
153 throw new IllegalStateException ("dcb.getSize() != 0");
154 byte[] tst = {'1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};
155 dcb.fill(tst);
156 if( dcb.getFreeSpace() != 1 )
157 throw new IllegalStateException ("dcb.getFreeSpace() != 1, "+dcb.getFreeSpace());
158 if( dcb.getSize() != 15 )
159 throw new IllegalStateException ("dcb.getSize() != 15");
160
161 byte[] tst2 = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};
162 dcb.clear();
163 dcb.fill(tst2);
164 if( dcb.getFreeSpace() != 0 )
165 throw new IllegalStateException ("dcb.getFreeSpace() != 0, "+dcb.getFreeSpace());
166 if( dcb.getSize() != 16 )
167 throw new IllegalStateException ("dcb.getSize() != 16");
168
169 dcb.clear();
170 dcb.fill(tst);
171 dcb.fill(tst2);
172 if( dcb.getFreeSpace() != 0 )
173 throw new IllegalStateException ("dcb.getFreeSpace() != 0, "+dcb.getFreeSpace());
174 if( dcb.getSize() != 31 )
175 throw new IllegalStateException ("dcb.getSize() != 31, "+dcb.getSize());
176
177 for(int i = 0; i < tst.length; i ++)
178 {
179 int b = dcb.get();
180 if( b != tst[i] )
181 throw new IllegalStateException ("tst["+i+","+tst[i]+"] != "+b);
182 }
183 for(int i = 0; i < tst2.length; i ++)
184 {
185 int b = dcb.get();
186 if( b != tst2[i] )
187 throw new IllegalStateException ("tst2["+i+","+tst2[i]+"] != "+b);
188 }
189 if( dcb.get() != -1 )
190 throw new IllegalStateException ("dcb.get() != -1");
191
192 dcb.fill(tst);
193 byte[] out = new byte[128];
194 int bytes = dcb.get(out, 0, 128);
195 if( bytes != 15 )
196 throw new IllegalStateException ("dcb.get(out, 0, 128) != 15, "+bytes);
197 if( dcb.getFreeSpace() != 31 )
198 throw new IllegalStateException ("dcb.getFreeSpace() != 31, "+dcb.getFreeSpace());
199 if( dcb.getSize() != 0 )
200 throw new IllegalStateException ("dcb.getSize() != 0, "+dcb.getSize());
201
202 dcb.clear();
203 for(int n = 0; n < 32; n ++)
204 {
205 dcb.fill(tst);
206 if( dcb.getFreeSpace() != 16 )
207 throw new IllegalStateException (n+", dcb.getFreeSpace() != 16, "+dcb.getFreeSpace());
208 if( dcb.getSize() != 15 )
209 throw new IllegalStateException (n+"dcb.getSize() != 15");
210 for(int i = 0; i < tst.length; i ++)
211 {
212 int b = dcb.get();
213 if( b != tst[i] )
214 throw new IllegalStateException (n+"tst["+i+","+tst[i]+"] != "+b);
215 }
216 if( dcb.get() != -1 )
217 throw new IllegalStateException (n+"dcb.get() != -1");
218 if( dcb.getFreeSpace() != 31 )
219 throw new IllegalStateException (n+", dcb.getFreeSpace() != 31, "+dcb.getFreeSpace());
220 }
221
222 byte[] tst3 = new byte[tst.length + tst2.length];
223 System.arraycopy(tst, 0, tst3, 0, tst.length);
224 System.arraycopy(tst2, 0, tst3, tst.length, tst2.length);
225 dcb.clear();
226 dcb.fill(tst3);
227 if( dcb.getFreeSpace() != 0 )
228 throw new IllegalStateException ("dcb.getFreeSpace() != 0, "+dcb.getFreeSpace());
229 if( dcb.getSize() != 31 )
230 throw new IllegalStateException ("dcb.getSize() != 31, "+dcb.getSize());
231 dcb.fill(tst);
232 if( dcb.getFreeSpace() != 0 )
233 throw new IllegalStateException ("dcb.getFreeSpace() != 0, "+dcb.getFreeSpace());
234 if( dcb.getSize() != 46 )
235 throw new IllegalStateException ("dcb.getSize() != 46, "+dcb.getSize());
236 for(int i = 0; i < tst.length; i ++)
237 {
238 int b = dcb.get();
239 if( b != tst[i] )
240 throw new IllegalStateException ("tst["+i+","+tst[i]+"] != "+b);
241 }
242 for(int i = 0; i < tst2.length; i ++)
243 {
244 int b = dcb.get();
245 if( b != tst2[i] )
246 throw new IllegalStateException ("tst2["+i+","+tst2[i]+"] != "+b);
247 }
248 for(int i = 0; i < tst.length; i ++)
249 {
250 int b = dcb.get();
251 if( b != tst[i] )
252 throw new IllegalStateException ("tst["+i+","+tst[i]+"] != "+b);
253 }
254
255 System.out.println("Done");
256 }
257 }
258 |
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