001: package org.apache.regexp;
002:
003: /*
004: * ====================================================================
005: *
006: * The Apache Software License, Version 1.1
007: *
008: * Copyright (c) 1999 The Apache Software Foundation. All rights
009: * reserved.
010: *
011: * Redistribution and use in source and binary forms, with or without
012: * modification, are permitted provided that the following conditions
013: * are met:
014: *
015: * 1. Redistributions of source code must retain the above copyright
016: * notice, this list of conditions and the following disclaimer.
017: *
018: * 2. Redistributions in binary form must reproduce the above copyright
019: * notice, this list of conditions and the following disclaimer in
020: * the documentation and/or other materials provided with the
021: * distribution.
022: *
023: * 3. The end-user documentation included with the redistribution, if
024: * any, must include the following acknowlegement:
025: * "This product includes software developed by the
026: * Apache Software Foundation (http://www.apache.org/)."
027: * Alternately, this acknowlegement may appear in the software itself,
028: * if and wherever such third-party acknowlegements normally appear.
029: *
030: * 4. The names "The Jakarta Project", "Jakarta-Regexp", and "Apache Software
031: * Foundation" must not be used to endorse or promote products derived
032: * from this software without prior written permission. For written
033: * permission, please contact apache@apache.org.
034: *
035: * 5. Products derived from this software may not be called "Apache"
036: * nor may "Apache" appear in their names without prior written
037: * permission of the Apache Group.
038: *
039: * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
040: * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
041: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
042: * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
043: * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
044: * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
045: * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
046: * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
047: * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
048: * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
049: * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
050: * SUCH DAMAGE.
051: * ====================================================================
052: *
053: * This software consists of voluntary contributions made by many
054: * individuals on behalf of the Apache Software Foundation. For more
055: * information on the Apache Software Foundation, please see
056: * <http://www.apache.org/>.
057: *
058: */
059:
060: import java.io.Reader;
061: import java.io.IOException;
062:
063: /** Encapsulates InputStream, ...
064: *
065: * @author <a href="mailto:ales.novak@netbeans.com">Ales Novak</a>
066: */
067: public final class ReaderCharacterIterator implements CharacterIterator {
068: /** Underlying is */
069: private final Reader reader;
070:
071: /** Buffer of read chars */
072: private final StringBuffer buff;
073:
074: /** read end? */
075: private boolean closed;
076:
077: /** @param is an Reader, which is parsed */
078: public ReaderCharacterIterator(Reader reader) {
079: this .reader = reader;
080: this .buff = new StringBuffer(512);
081: this .closed = false;
082: }
083:
084: /** @return a substring */
085: public String substring(int offset, int length) {
086: try {
087: ensure(offset + length);
088: return buff.toString().substring(offset, length);
089: } catch (IOException e) {
090: throw new StringIndexOutOfBoundsException(e.getMessage());
091: }
092: }
093:
094: /** @return a substring */
095: public String substring(int offset) {
096: try {
097: readAll();
098: return buff.toString().substring(offset);
099: } catch (IOException e) {
100: throw new StringIndexOutOfBoundsException(e.getMessage());
101: }
102: }
103:
104: /** @return a character at the specified position. */
105: public char charAt(int pos) {
106: try {
107: ensure(pos);
108: return buff.charAt(pos);
109: } catch (IOException e) {
110: throw new StringIndexOutOfBoundsException(e.getMessage());
111: }
112: }
113:
114: /** @return <tt>true</tt> iff if the specified index is after the end of the character stream */
115: public boolean isEnd(int pos) {
116: if (buff.length() > pos) {
117: return false;
118: } else {
119: try {
120: ensure(pos);
121: return (buff.length() <= pos);
122: } catch (IOException e) {
123: throw new StringIndexOutOfBoundsException(e
124: .getMessage());
125: }
126: }
127: }
128:
129: /** Reads n characters from the stream and appends them to the buffer */
130: private int read(int n) throws IOException {
131: if (closed) {
132: return 0;
133: }
134:
135: char[] c = new char[n];
136: int count = 0;
137: int read = 0;
138:
139: do {
140: read = reader.read(c);
141: if (read < 0) // EOF
142: {
143: closed = true;
144: break;
145: }
146: count += read;
147: buff.append(c, 0, read);
148: } while (count < n);
149:
150: return count;
151: }
152:
153: /** Reads rest of the stream. */
154: private void readAll() throws IOException {
155: while (!closed) {
156: read(1000);
157: }
158: }
159:
160: /** Reads chars up to the idx */
161: private void ensure(int idx) throws IOException {
162: if (closed) {
163: return;
164: }
165:
166: if (idx < buff.length()) {
167: return;
168: }
169: read(idx + 1 - buff.length());
170: }
171: }
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