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1 package com.opensymphony.module.sitemesh.util;
2
3 import java.io.Writer;
4 import java.io.IOException;
5
6 /**
7 * Unsynced version of the JDK's CharArrayWriter
8 */
9 public class CharArrayWriter extends Writer {
10 /**
11 * The buffer where data is stored.
12 */
13 protected char buf[];
14
15 /**
16 * The number of chars in the buffer.
17 */
18 protected int count;
19
20 /**
21 * Creates a new CharArrayWriter.
22 */
23 public CharArrayWriter() {
24 this(32);
25 }
26
27 /**
28 * Creates a new CharArrayWriter with the specified initial size.
29 *
30 * @param initialSize an int specifying the initial buffer size.
31 * @exception IllegalArgumentException if initialSize is negative
32 */
33 public CharArrayWriter(int initialSize) {
34 if (initialSize < 0) {
35 throw new IllegalArgumentException("Negative initial size: "
36 + initialSize);
37 }
38 buf = new char[initialSize];
39 }
40
41 /**
42 * Writes a character to the buffer.
43 */
44 public void write(int c) {
45 int newcount = count + 1;
46 if (newcount > buf.length) {
47 char newbuf[] = new char[Math.max(buf.length << 1, newcount)];
48 System.arraycopy(buf, 0, newbuf, 0, count);
49 buf = newbuf;
50 }
51 buf[count] = (char)c;
52 count = newcount;
53 }
54
55 /**
56 * Writes characters to the buffer.
57 * @param c the data to be written
58 * @param off the start offset in the data
59 * @param len the number of chars that are written
60 */
61 public void write(char c[], int off, int len) {
62 if ((off < 0) || (off > c.length) || (len < 0) ||
63 ((off + len) > c.length) || ((off + len) < 0)) {
64 throw new IndexOutOfBoundsException();
65 } else if (len == 0) {
66 return;
67 }
68 int newcount = count + len;
69 if (newcount > buf.length) {
70 char newbuf[] = new char[Math.max(buf.length << 1, newcount)];
71 System.arraycopy(buf, 0, newbuf, 0, count);
72 buf = newbuf;
73 }
74 System.arraycopy(c, off, buf, count, len);
75 count = newcount;
76 }
77
78 /**
79 * Write a portion of a string to the buffer.
80 * @param str String to be written from
81 * @param off Offset from which to start reading characters
82 * @param len Number of characters to be written
83 */
84 public void write(String str, int off, int len) {
85 int newcount = count + len;
86 if (newcount > buf.length) {
87 char newbuf[] = new char[Math.max(buf.length << 1, newcount)];
88 System.arraycopy(buf, 0, newbuf, 0, count);
89 buf = newbuf;
90 }
91 str.getChars(off, off + len, buf, count);
92 count = newcount;
93 }
94
95 /**
96 * Writes the contents of the buffer to another character stream.
97 *
98 * @param out the output stream to write to
99 * @throws java.io.IOException If an I/O error occurs.
100 */
101 public void writeTo(Writer out) throws IOException {
102 out.write(buf, 0, count);
103 }
104
105 /**
106 * Resets the buffer so that you can use it again without
107 * throwing away the already allocated buffer.
108 */
109 public void reset() {
110 count = 0;
111 }
112
113 /**
114 * Returns a copy of the input data.
115 *
116 * @return an array of chars copied from the input data.
117 */
118 public char toCharArray()[] {
119 char newbuf[] = new char[count];
120 System.arraycopy(buf, 0, newbuf, 0, count);
121 return newbuf;
122 }
123
124 /**
125 * Returns the current size of the buffer.
126 *
127 * @return an int representing the current size of the buffer.
128 */
129 public int size() {
130 return count;
131 }
132
133 /**
134 * Converts input data to a string.
135 * @return the string.
136 */
137 public String toString() {
138 return new String(buf, 0, count);
139 }
140
141 /**
142 * Flush the stream.
143 */
144 public void flush() { }
145
146 /**
147 * Close the stream. This method does not release the buffer, since its
148 * contents might still be required.
149 */
150 public void close() { }
151
152 }