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1
52
53 package com.go.trove.io;
54
55 import java.io.*;
56 import java.util.*;
57 import com.go.trove.util.IdentityMap;
58
59
69 public class InternedCharToByteBuffer
70 implements CharToByteBuffer, Serializable
71 {
72 private static final int CACHES_PER_ENCODING = 11;
73 private static final int MIN_LENGTH = 4;
74
75 private static final Object  MARKER = new Object ();
76
77 private static Map cEncodings = new HashMap(7);
78
79 private static Random cLastRandom = new Random();
80
81
87 private static Map[] getConvertedCaches(String encoding) {
88 synchronized (cEncodings) {
89 Map[] caches = (Map[])cEncodings.get(encoding);
90 if (caches == null) {
91 caches = new Map[CACHES_PER_ENCODING];
92 for (int i=0; i<CACHES_PER_ENCODING; i++) {
93 caches[i] = Collections.synchronizedMap(new IdentityMap());
94 }
95 cEncodings.put(encoding, caches);
96 }
97 return caches;
98 }
99 }
100
101 private static Random getRandom() {
102 synchronized (cLastRandom) {
103 return cLastRandom = new Random(cLastRandom.nextLong());
104 }
105 }
106
107 private CharToByteBuffer mBuffer;
108 private Random mRandom;
109 private transient Map[] mConvertedCaches;
110
111 public InternedCharToByteBuffer(CharToByteBuffer buffer)
112 throws IOException
113 {
114 mBuffer = buffer;
115 mConvertedCaches = getConvertedCaches(buffer.getEncoding());
116 }
117
118 public void setEncoding(String enc) throws IOException {
119 mBuffer.setEncoding(enc);
120 mConvertedCaches = getConvertedCaches(mBuffer.getEncoding());
121 }
122
123 public String getEncoding() throws IOException {
124 return mBuffer.getEncoding();
125 }
126
127 public long getBaseByteCount() throws IOException {
128 return mBuffer.getBaseByteCount();
129 }
130
131 public long getByteCount() throws IOException {
132 return mBuffer.getByteCount();
133 }
134
135 public void writeTo(OutputStream out) throws IOException {
136 mBuffer.writeTo(out);
137 }
138
139 public void append(byte b) throws IOException {
140 mBuffer.append(b);
141 }
142
143 public void append(byte[] bytes) throws IOException {
144 mBuffer.append(bytes);
145 }
146
147 public void append(byte[] bytes, int offset, int length)
148 throws IOException {
149
150 mBuffer.append(bytes, offset, length);
151 }
152
153 public void appendSurrogate(ByteData s) throws IOException {
154 mBuffer.appendSurrogate(s);
155 }
156
157 public void addCaptureBuffer(ByteBuffer buffer) throws IOException {
158 mBuffer.addCaptureBuffer(buffer);
159 }
160
161 public void removeCaptureBuffer(ByteBuffer buffer) throws IOException {
162 mBuffer.removeCaptureBuffer(buffer);
163 }
164
165 public void append(char c) throws IOException {
166 mBuffer.append(c);
167 }
168
169 public void append(char[] chars) throws IOException {
170 mBuffer.append(chars);
171 }
172
173 public void append(char[] chars, int offset, int length)
174 throws IOException {
175
176 mBuffer.append(chars, offset, length);
177 }
178
179 public void append(String str) throws IOException {
180 Map cache;
181 if ((cache = getConvertedCache(str)) == null) {
182 mBuffer.append(str);
183 return;
184 }
185
186
190 Object value;
191
192 if ((value = cache.get(str)) != null) {
193 byte[] bytes;
194 if (value != MARKER) {
195 bytes = (byte[])value;
196 }
197 else {
198 String enc = getEncoding();
201 if (enc != null) {
202 bytes = str.getBytes(enc);
203 }
204 else {
205 bytes = str.getBytes();
207 }
208 cache.put(str, bytes);
209 }
210
211 mBuffer.append(bytes);
212 }
213 else {
214 if (mRandom == null) {
217 mRandom = getRandom();
218 }
219 if ((mRandom.nextInt() % 20) == 0) {
220 cache.put(str, MARKER);
228 }
229 mBuffer.append(str);
230 }
231 }
232
233 public void append(String str, int offset, int length) throws IOException {
234 mBuffer.append(str, offset, length);
235 }
236
237 public void reset() throws IOException {
238 mBuffer.reset();
239 }
240
241 public void drain() throws IOException {
242 mBuffer.drain();
243 }
244
245 private Map getConvertedCache(String str) {
246 if (str.length() < MIN_LENGTH) {
247 return null;
248 }
249 return mConvertedCaches[str.charAt(1) % CACHES_PER_ENCODING];
250 }
251
252 private void readObject(ObjectInputStream in)
253 throws IOException, ClassNotFoundException
254 {
255 in.defaultReadObject();
256 mConvertedCaches = getConvertedCaches(mBuffer.getEncoding());
257 }
258 }
259 |
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