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1
51 package org.apache.fop.render.ps;
52
53 import java.io.FilterOutputStream  ;
54 import java.io.OutputStream ;
55 import java.io.IOException ;
56
57
63
64 public class RunLengthEncodeOutputStream extends FilterOutputStream
65 implements Finalizable {
66
67 private static final int MAX_SEQUENCE_COUNT = 127;
68 private static final int END_OF_DATA = 128;
69 private static final int BYTE_MAX = 256;
70
71 private static final int NOT_IDENTIFY_SEQUENCE = 0;
72 private static final int START_SEQUENCE = 1;
73 private static final int IN_SEQUENCE = 2;
74 private static final int NOT_IN_SEQUENCE = 3;
75
76 private int runCount = 0;
77 private int isSequence = NOT_IDENTIFY_SEQUENCE;
78 private byte[] runBuffer = new byte[MAX_SEQUENCE_COUNT + 1];
79
80
81
86 public RunLengthEncodeOutputStream(OutputStream out) {
87 super(out);
88 }
89
90
91
98 public void write(byte b)
99 throws java.io.IOException {
100 runBuffer[runCount] = b;
101
102 switch (runCount) {
103 case 0:
104 runCount = 0;
105 isSequence = NOT_IDENTIFY_SEQUENCE;
106 runCount++;
107 break;
108 case 1:
109 if (runBuffer[runCount] != runBuffer[runCount - 1]) {
110 isSequence = NOT_IN_SEQUENCE;
111 }
112 runCount++;
113 break;
114 case 2:
115 if (runBuffer[runCount] != runBuffer[runCount - 1]) {
116 isSequence = NOT_IN_SEQUENCE;
117 } else {
118 if (isSequence == NOT_IN_SEQUENCE) {
119 isSequence = START_SEQUENCE;
120 } else {
121 isSequence = IN_SEQUENCE;
122 }
123 }
124 runCount++;
125 break;
126 case MAX_SEQUENCE_COUNT:
127 if (isSequence == IN_SEQUENCE) {
128 out.write(BYTE_MAX - (MAX_SEQUENCE_COUNT - 1));
129 out.write(runBuffer[runCount - 1]);
130 runBuffer[0] = runBuffer[runCount];
131 runCount = 1;
132 } else {
133 out.write(MAX_SEQUENCE_COUNT);
134 out.write(runBuffer, 0, runCount + 1);
135 runCount = 0;
136 }
137 isSequence = NOT_IDENTIFY_SEQUENCE;
138 break;
139 default:
140 switch (isSequence) {
141 case IN_SEQUENCE:
142 if (runBuffer[runCount] != runBuffer[runCount - 1]) {
143 out.write(BYTE_MAX - (runCount - 1));
144 out.write(runBuffer[runCount - 1]);
145 runBuffer[0] = runBuffer[runCount];
146 runCount = 1;
147 isSequence = NOT_IDENTIFY_SEQUENCE;
148 break;
149 }
150 runCount++;
151 break;
152 case NOT_IN_SEQUENCE:
153 if (runBuffer[runCount] == runBuffer[runCount - 1]) {
154 isSequence = START_SEQUENCE;
155 }
156 runCount++;
157 break;
158 case START_SEQUENCE:
159 if (runBuffer[runCount] == runBuffer[runCount - 1]) {
160 out.write(runCount - 3);
161 out.write(runBuffer, 0, runCount - 2);
162 runBuffer[0] = runBuffer[runCount];
163 runBuffer[1] = runBuffer[runCount];
164 runBuffer[2] = runBuffer[runCount];
165 runCount = 3;
166 isSequence = IN_SEQUENCE;
167 break;
168 } else {
169 isSequence = NOT_IN_SEQUENCE;
170 runCount++;
171 break;
172 }
173 }
174 }
175 }
176
177
178
183 public void write(byte[] b)
184 throws IOException {
185
186 for (int i = 0; i < b.length; i++) {
187 this.write(b[i]);
188 }
189 }
190
191
192
201 public void write(byte[] b, int off, int len)
202 throws IOException {
203
204 for (int i = 0; i < len; i++) {
205 this.write(b[off + i]);
206 }
207 }
208
209
210
216 public void finalizeStream()
217 throws IOException {
218 switch (isSequence) {
219 case IN_SEQUENCE:
220 out.write(BYTE_MAX - (runCount - 1));
221 out.write(runBuffer[runCount - 1]);
222 break;
223 default:
224 out.write(runCount - 1);
225 out.write(runBuffer, 0, runCount);
226 }
227
228 out.write(END_OF_DATA);
229
230 flush();
231 if (out instanceof Finalizable) {
232 ((Finalizable) out).finalizeStream();
233 }
234 }
235
236
237
242 public void close()
243 throws IOException {
244 finalizeStream();
245 super.close();
246 }
247
248 }
249
250 |
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