001: /*--
002:
003: $Id: TextBuffer.java,v 1.8 2004/02/06 09:28:31 jhunter Exp $
004:
005: Copyright (C) 2000-2004 Jason Hunter & Brett McLaughlin.
006: All rights reserved.
007:
008: Redistribution and use in source and binary forms, with or without
009: modification, are permitted provided that the following conditions
010: are met:
011:
012: 1. Redistributions of source code must retain the above copyright
013: notice, this list of conditions, and the following disclaimer.
014:
015: 2. Redistributions in binary form must reproduce the above copyright
016: notice, this list of conditions, and the disclaimer that follows
017: these conditions in the documentation and/or other materials
018: provided with the distribution.
019:
020: 3. The name "JDOM" must not be used to endorse or promote products
021: derived from this software without prior written permission. For
022: written permission, please contact <request_AT_jdom_DOT_org>.
023:
024: 4. Products derived from this software may not be called "JDOM", nor
025: may "JDOM" appear in their name, without prior written permission
026: from the JDOM Project Management <request_AT_jdom_DOT_org>.
027:
028: In addition, we request (but do not require) that you include in the
029: end-user documentation provided with the redistribution and/or in the
030: software itself an acknowledgement equivalent to the following:
031: "This product includes software developed by the
032: JDOM Project (http://www.jdom.org/)."
033: Alternatively, the acknowledgment may be graphical using the logos
034: available at http://www.jdom.org/images/logos.
035:
036: THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
037: WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
038: OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
039: DISCLAIMED. IN NO EVENT SHALL THE JDOM AUTHORS OR THE PROJECT
040: CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
041: SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
042: LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
043: USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
044: ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
045: OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
046: OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
047: SUCH DAMAGE.
048:
049: This software consists of voluntary contributions made by many
050: individuals on behalf of the JDOM Project and was originally
051: created by Jason Hunter <jhunter_AT_jdom_DOT_org> and
052: Brett McLaughlin <brett_AT_jdom_DOT_org>. For more information
053: on the JDOM Project, please see <http://www.jdom.org/>.
054:
055: */
056:
057: package org.jdom.input;
058:
059: /**
060: * A non-public utility class similar to StringBuffer but optimized for XML
061: * parsing where the common case is that you get only one chunk of characters
062: * per text section. TextBuffer stores the first chunk of characters in a
063: * String, which can just be returned directly if no second chunk is received.
064: * Subsequent chunks are stored in a supplemental char array (like StringBuffer
065: * uses). In this case, the returned text will be the first String chunk,
066: * concatenated with the subsequent chunks stored in the char array. This
067: * provides optimal performance in the common case, while still providing very
068: * good performance in the uncommon case. Furthermore, avoiding StringBuffer
069: * means that no extra unused char array space will be kept around after parsing
070: * is through.
071: *
072: * @version $Revision: 1.8 $, $Date: 2004/02/06 09:28:31 $
073: * @author Bradley S. Huffman
074: * @author Alex Rosen
075: */
076: class TextBuffer {
077:
078: private static final String CVS_ID = "@(#) $RCSfile: TextBuffer.java,v $ $Revision: 1.8 $ $Date: 2004/02/06 09:28:31 $ $Name: jdom_1_0 $";
079:
080: /** The first part of the text value (the "prefix"). If null, the
081: * text value is the empty string. */
082: private String prefixString;
083:
084: /** The rest of the text value (the "suffix"). Only the first
085: * code>arraySize</code> characters are valid. */
086: private char[] array;
087:
088: /** The size of the rest of the text value. If zero, then only
089: * code>prefixString</code> contains the text value. */
090: private int arraySize;
091:
092: /** Constructor */
093: TextBuffer() {
094: array = new char[4096]; // initial capacity
095: arraySize = 0;
096: }
097:
098: /** Append the specified text to the text value of this buffer. */
099: void append(char[] source, int start, int count) {
100: if (prefixString == null) {
101: // This is the first chunk, so we'll store it in the prefix string
102: prefixString = new String(source, start, count);
103: } else {
104: // This is a subsequent chunk, so we'll add it to the char array
105: ensureCapacity(arraySize + count);
106: System.arraycopy(source, start, array, arraySize, count);
107: arraySize += count;
108: }
109: }
110:
111: /** Returns the size of the text value. */
112: int size() {
113: if (prefixString == null) {
114: return 0;
115: } else {
116: return prefixString.length() + arraySize;
117: }
118: }
119:
120: /** Clears the text value and prepares the TextBuffer for reuse. */
121: void clear() {
122: arraySize = 0;
123: prefixString = null;
124: }
125:
126: /** Returns the text value stored in the buffer. */
127: public String toString() {
128: if (prefixString == null) {
129: return "";
130: }
131:
132: String str = "";
133: if (arraySize == 0) {
134: // Char array is empty, so the text value is just prefixString.
135: str = prefixString;
136: } else {
137: // Char array is not empty, so the text value is prefixString
138: // plus the char array.
139: str = new StringBuffer(prefixString.length() + arraySize)
140: .append(prefixString).append(array, 0, arraySize)
141: .toString();
142: }
143: return str;
144: }
145:
146: // Ensure that the char array has room for at least "csize" characters.
147: private void ensureCapacity(int csize) {
148: int capacity = array.length;
149: if (csize > capacity) {
150: char[] old = array;
151: int nsize = capacity;
152: while (csize > nsize) {
153: nsize += (capacity / 2);
154: }
155: array = new char[nsize];
156: System.arraycopy(old, 0, array, 0, arraySize);
157: }
158: }
159: }
|