1 /*
2 * ====================================================================
3 * Licensed to the Apache Software Foundation (ASF) under one
4 * or more contributor license agreements. See the NOTICE file
5 * distributed with this work for additional information
6 * regarding copyright ownership. The ASF licenses this file
7 * to you under the Apache License, Version 2.0 (the
8 * "License"); you may not use this file except in compliance
9 * with the License. You may obtain a copy of the License at
10 *
11 * http://www.apache.org/licenses/LICENSE-2.0
12 *
13 * Unless required by applicable law or agreed to in writing,
14 * software distributed under the License is distributed on an
15 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
16 * KIND, either express or implied. See the License for the
17 * specific language governing permissions and limitations
18 * under the License.
19 * ====================================================================
20 *
21 * This software consists of voluntary contributions made by many
22 * individuals on behalf of the Apache Software Foundation. For more
23 * information on the Apache Software Foundation, please see
24 * <http://www.apache.org/>.
25 *
26 */
27
28 package org.apache.http.util;
29
30 import java.io.Serializable;
31
32 import org.apache.http.annotation.NotThreadSafe;
33 import org.apache.http.protocol.HTTP;
34
35 /**
36 * A resizable char array.
37 *
38 * @since 4.0
39 */
40 @NotThreadSafe
41 public final class CharArrayBuffer implements Serializable {
42
43 private static final long serialVersionUID = -6208952725094867135L;
44
45 private char[] buffer;
46 private int len;
47
48 /**
49 * Creates an instance of {@link CharArrayBuffer} with the given initial
50 * capacity.
51 *
52 * @param capacity the capacity
53 */
54 public CharArrayBuffer(int capacity) {
55 super();
56 if (capacity < 0) {
57 throw new IllegalArgumentException("Buffer capacity may not be negative");
58 }
59 this.buffer = new char[capacity];
60 }
61
62 private void expand(int newlen) {
63 char newbuffer[] = new char[Math.max(this.buffer.length << 1, newlen)];
64 System.arraycopy(this.buffer, 0, newbuffer, 0, this.len);
65 this.buffer = newbuffer;
66 }
67
68 /**
69 * Appends <code>len</code> chars to this buffer from the given source
70 * array starting at index <code>off</code>. The capacity of the buffer
71 * is increased, if necessary, to accommodate all <code>len</code> chars.
72 *
73 * @param b the chars to be appended.
74 * @param off the index of the first char to append.
75 * @param len the number of chars to append.
76 * @throws IndexOutOfBoundsException if <code>off</code> is out of
77 * range, <code>len</code> is negative, or
78 * <code>off</code> + <code>len</code> is out of range.
79 */
80 public void append(final char[] b, int off, int len) {
81 if (b == null) {
82 return;
83 }
84 if ((off < 0) || (off > b.length) || (len < 0) ||
85 ((off + len) < 0) || ((off + len) > b.length)) {
86 throw new IndexOutOfBoundsException("off: "+off+" len: "+len+" b.length: "+b.length);
87 }
88 if (len == 0) {
89 return;
90 }
91 int newlen = this.len + len;
92 if (newlen > this.buffer.length) {
93 expand(newlen);
94 }
95 System.arraycopy(b, off, this.buffer, this.len, len);
96 this.len = newlen;
97 }
98
99 /**
100 * Appends chars of the given string to this buffer. The capacity of the
101 * buffer is increased, if necessary, to accommodate all chars.
102 *
103 * @param str the string.
104 */
105 public void append(String str) {
106 if (str == null) {
107 str = "null";
108 }
109 int strlen = str.length();
110 int newlen = this.len + strlen;
111 if (newlen > this.buffer.length) {
112 expand(newlen);
113 }
114 str.getChars(0, strlen, this.buffer, this.len);
115 this.len = newlen;
116 }
117
118 /**
119 * Appends <code>len</code> chars to this buffer from the given source
120 * buffer starting at index <code>off</code>. The capacity of the
121 * destination buffer is increased, if necessary, to accommodate all
122 * <code>len</code> chars.
123 *
124 * @param b the source buffer to be appended.
125 * @param off the index of the first char to append.
126 * @param len the number of chars to append.
127 * @throws IndexOutOfBoundsException if <code>off</code> is out of
128 * range, <code>len</code> is negative, or
129 * <code>off</code> + <code>len</code> is out of range.
130 */
131 public void append(final CharArrayBuffer b, int off, int len) {
132 if (b == null) {
133 return;
134 }
135 append(b.buffer, off, len);
136 }
137
138 /**
139 * Appends all chars to this buffer from the given source buffer starting
140 * at index <code>0</code>. The capacity of the destination buffer is
141 * increased, if necessary, to accommodate all {@link #length()} chars.
142 *
143 * @param b the source buffer to be appended.
144 */
145 public void append(final CharArrayBuffer b) {
146 if (b == null) {
147 return;
148 }
149 append(b.buffer,0, b.len);
150 }
151
152 /**
153 * Appends <code>ch</code> char to this buffer. The capacity of the buffer
154 * is increased, if necessary, to accommodate the additional char.
155 *
156 * @param ch the char to be appended.
157 */
158 public void append(char ch) {
159 int newlen = this.len + 1;
160 if (newlen > this.buffer.length) {
161 expand(newlen);
162 }
163 this.buffer[this.len] = ch;
164 this.len = newlen;
165 }
166
167 /**
168 * Appends <code>len</code> bytes to this buffer from the given source
169 * array starting at index <code>off</code>. The capacity of the buffer
170 * is increased, if necessary, to accommodate all <code>len</code> bytes.
171 * <p>
172 * The bytes are converted to chars using simple cast.
173 *
174 * @param b the bytes to be appended.
175 * @param off the index of the first byte to append.
176 * @param len the number of bytes to append.
177 * @throws IndexOutOfBoundsException if <code>off</code> is out of
178 * range, <code>len</code> is negative, or
179 * <code>off</code> + <code>len</code> is out of range.
180 */
181 public void append(final byte[] b, int off, int len) {
182 if (b == null) {
183 return;
184 }
185 if ((off < 0) || (off > b.length) || (len < 0) ||
186 ((off + len) < 0) || ((off + len) > b.length)) {
187 throw new IndexOutOfBoundsException("off: "+off+" len: "+len+" b.length: "+b.length);
188 }
189 if (len == 0) {
190 return;
191 }
192 int oldlen = this.len;
193 int newlen = oldlen + len;
194 if (newlen > this.buffer.length) {
195 expand(newlen);
196 }
197 for (int i1 = off, i2 = oldlen; i2 < newlen; i1++, i2++) {
198 this.buffer[i2] = (char) (b[i1] & 0xff);
199 }
200 this.len = newlen;
201 }
202
203 /**
204 * Appends <code>len</code> bytes to this buffer from the given source
205 * array starting at index <code>off</code>. The capacity of the buffer
206 * is increased, if necessary, to accommodate all <code>len</code> bytes.
207 * <p>
208 * The bytes are converted to chars using simple cast.
209 *
210 * @param b the bytes to be appended.
211 * @param off the index of the first byte to append.
212 * @param len the number of bytes to append.
213 * @throws IndexOutOfBoundsException if <code>off</code> is out of
214 * range, <code>len</code> is negative, or
215 * <code>off</code> + <code>len</code> is out of range.
216 */
217 public void append(final ByteArrayBuffer b, int off, int len) {
218 if (b == null) {
219 return;
220 }
221 append(b.buffer(), off, len);
222 }
223
224 /**
225 * Appends chars of the textual representation of the given object to this
226 * buffer. The capacity of the buffer is increased, if necessary, to
227 * accommodate all chars.
228 *
229 * @param obj the object.
230 */
231 public void append(final Object obj) {
232 append(String.valueOf(obj));
233 }
234
235 /**
236 * Clears content of the buffer. The underlying char array is not resized.
237 */
238 public void clear() {
239 this.len = 0;
240 }
241
242 /**
243 * Converts the content of this buffer to an array of chars.
244 *
245 * @return char array
246 */
247 public char[] toCharArray() {
248 char[] b = new char[this.len];
249 if (this.len > 0) {
250 System.arraycopy(this.buffer, 0, b, 0, this.len);
251 }
252 return b;
253 }
254
255 /**
256 * Returns the <code>char</code> value in this buffer at the specified
257 * index. The index argument must be greater than or equal to
258 * <code>0</code>, and less than the length of this buffer.
259 *
260 * @param i the index of the desired char value.
261 * @return the char value at the specified index.
262 * @throws IndexOutOfBoundsException if <code>index</code> is
263 * negative or greater than or equal to {@link #length()}.
264 */
265 public char charAt(int i) {
266 return this.buffer[i];
267 }
268
269 /**
270 * Returns reference to the underlying char array.
271 *
272 * @return the char array.
273 */
274 public char[] buffer() {
275 return this.buffer;
276 }
277
278 /**
279 * Returns the current capacity. The capacity is the amount of storage
280 * available for newly appended chars, beyond which an allocation will
281 * occur.
282 *
283 * @return the current capacity
284 */
285 public int capacity() {
286 return this.buffer.length;
287 }
288
289 /**
290 * Returns the length of the buffer (char count).
291 *
292 * @return the length of the buffer
293 */
294 public int length() {
295 return this.len;
296 }
297
298 /**
299 * Ensures that the capacity is at least equal to the specified minimum.
300 * If the current capacity is less than the argument, then a new internal
301 * array is allocated with greater capacity. If the <code>required</code>
302 * argument is non-positive, this method takes no action.
303 *
304 * @param required the minimum required capacity.
305 */
306 public void ensureCapacity(int required) {
307 if (required <= 0) {
308 return;
309 }
310 int available = this.buffer.length - this.len;
311 if (required > available) {
312 expand(this.len + required);
313 }
314 }
315
316 /**
317 * Sets the length of the buffer. The new length value is expected to be
318 * less than the current capacity and greater than or equal to
319 * <code>0</code>.
320 *
321 * @param len the new length
322 * @throws IndexOutOfBoundsException if the
323 * <code>len</code> argument is greater than the current
324 * capacity of the buffer or less than <code>0</code>.
325 */
326 public void setLength(int len) {
327 if (len < 0 || len > this.buffer.length) {
328 throw new IndexOutOfBoundsException("len: "+len+" < 0 or > buffer len: "+this.buffer.length);
329 }
330 this.len = len;
331 }
332
333 /**
334 * Returns <code>true</code> if this buffer is empty, that is, its
335 * {@link #length()} is equal to <code>0</code>.
336 * @return <code>true</code> if this buffer is empty, <code>false</code>
337 * otherwise.
338 */
339 public boolean isEmpty() {
340 return this.len == 0;
341 }
342
343 /**
344 * Returns <code>true</code> if this buffer is full, that is, its
345 * {@link #length()} is equal to its {@link #capacity()}.
346 * @return <code>true</code> if this buffer is full, <code>false</code>
347 * otherwise.
348 */
349 public boolean isFull() {
350 return this.len == this.buffer.length;
351 }
352
353 /**
354 * Returns the index within this buffer of the first occurrence of the
355 * specified character, starting the search at the specified
356 * <code>beginIndex</code> and finishing at <code>endIndex</code>.
357 * If no such character occurs in this buffer within the specified bounds,
358 * <code>-1</code> is returned.
359 * <p>
360 * There is no restriction on the value of <code>beginIndex</code> and
361 * <code>endIndex</code>. If <code>beginIndex</code> is negative,
362 * it has the same effect as if it were zero. If <code>endIndex</code> is
363 * greater than {@link #length()}, it has the same effect as if it were
364 * {@link #length()}. If the <code>beginIndex</code> is greater than
365 * the <code>endIndex</code>, <code>-1</code> is returned.
366 *
367 * @param ch the char to search for.
368 * @param beginIndex the index to start the search from.
369 * @param endIndex the index to finish the search at.
370 * @return the index of the first occurrence of the character in the buffer
371 * within the given bounds, or <code>-1</code> if the character does
372 * not occur.
373 */
374 public int indexOf(int ch, int beginIndex, int endIndex) {
375 if (beginIndex < 0) {
376 beginIndex = 0;
377 }
378 if (endIndex > this.len) {
379 endIndex = this.len;
380 }
381 if (beginIndex > endIndex) {
382 return -1;
383 }
384 for (int i = beginIndex; i < endIndex; i++) {
385 if (this.buffer[i] == ch) {
386 return i;
387 }
388 }
389 return -1;
390 }
391
392 /**
393 * Returns the index within this buffer of the first occurrence of the
394 * specified character, starting the search at <code>0</code> and finishing
395 * at {@link #length()}. If no such character occurs in this buffer within
396 * those bounds, <code>-1</code> is returned.
397 *
398 * @param ch the char to search for.
399 * @return the index of the first occurrence of the character in the
400 * buffer, or <code>-1</code> if the character does not occur.
401 */
402 public int indexOf(int ch) {
403 return indexOf(ch, 0, this.len);
404 }
405
406 /**
407 * Returns a substring of this buffer. The substring begins at the specified
408 * <code>beginIndex</code> and extends to the character at index
409 * <code>endIndex - 1</code>.
410 *
411 * @param beginIndex the beginning index, inclusive.
412 * @param endIndex the ending index, exclusive.
413 * @return the specified substring.
414 * @exception StringIndexOutOfBoundsException if the
415 * <code>beginIndex</code> is negative, or
416 * <code>endIndex</code> is larger than the length of this
417 * buffer, or <code>beginIndex</code> is larger than
418 * <code>endIndex</code>.
419 */
420 public String substring(int beginIndex, int endIndex) {
421 return new String(this.buffer, beginIndex, endIndex - beginIndex);
422 }
423
424 /**
425 * Returns a substring of this buffer with leading and trailing whitespace
426 * omitted. The substring begins with the first non-whitespace character
427 * from <code>beginIndex</code> and extends to the last
428 * non-whitespace character with the index lesser than
429 * <code>endIndex</code>.
430 *
431 * @param beginIndex the beginning index, inclusive.
432 * @param endIndex the ending index, exclusive.
433 * @return the specified substring.
434 * @exception IndexOutOfBoundsException if the
435 * <code>beginIndex</code> is negative, or
436 * <code>endIndex</code> is larger than the length of this
437 * buffer, or <code>beginIndex</code> is larger than
438 * <code>endIndex</code>.
439 */
440 public String substringTrimmed(int beginIndex, int endIndex) {
441 if (beginIndex < 0) {
442 throw new IndexOutOfBoundsException("Negative beginIndex: "+beginIndex);
443 }
444 if (endIndex > this.len) {
445 throw new IndexOutOfBoundsException("endIndex: "+endIndex+" > length: "+this.len);
446 }
447 if (beginIndex > endIndex) {
448 throw new IndexOutOfBoundsException("beginIndex: "+beginIndex+" > endIndex: "+endIndex);
449 }
450 while (beginIndex < endIndex && HTTP.isWhitespace(this.buffer[beginIndex])) {
451 beginIndex++;
452 }
453 while (endIndex > beginIndex && HTTP.isWhitespace(this.buffer[endIndex - 1])) {
454 endIndex--;
455 }
456 return new String(this.buffer, beginIndex, endIndex - beginIndex);
457 }
458
459 @Override
460 public String toString() {
461 return new String(this.buffer, 0, this.len);
462 }
463
464 }