| /******************************************************************************* |
| * Copyright (c) 2011 Tasktop Technologies. |
| * All rights reserved. This program and the accompanying materials |
| * are made available under the terms of the Eclipse Public License v1.0 |
| * which accompanies this distribution, and is available at |
| * http://www.eclipse.org/legal/epl-v10.html |
| * |
| * Contributors: |
| * Tasktop Technologies - initial API and implementation |
| *******************************************************************************/ |
| |
| package org.eclipse.mylyn.internal.sandbox.search.ui.provider; |
| |
| import java.io.IOException; |
| import java.io.Reader; |
| |
| import org.eclipse.core.runtime.IProgressMonitor; |
| import org.eclipse.core.runtime.OperationCanceledException; |
| |
| /** |
| * A CharSequence that is based on a reader, providing a specified number of characters. If the reader cannot provide |
| * enough character data, the sequence is padded with whitespace. |
| * |
| * @author David Green |
| */ |
| class ReaderCharSequence implements CharSequence { |
| |
| private final int length; |
| |
| private Reader reader; |
| |
| private final StringBuilder buffer; |
| |
| private final IProgressMonitor monitor; |
| |
| public ReaderCharSequence(int length, Reader reader, IProgressMonitor monitor) { |
| this.length = length; |
| this.reader = reader; |
| this.monitor = monitor; |
| buffer = new StringBuilder(length > 1024 ? 1024 : length); |
| } |
| |
| public int length() { |
| return length; |
| } |
| |
| public char charAt(int index) { |
| if (index >= length || index < 0) { |
| throw new IndexOutOfBoundsException(); |
| } |
| if (index >= buffer.length()) { |
| fill(index); |
| } |
| if (index >= buffer.length()) { |
| return ' '; |
| } |
| return buffer.charAt(index); |
| } |
| |
| private void fill(int maxIndex) { |
| if (reader == null) { |
| return; |
| } |
| int c; |
| while (buffer.length() <= maxIndex) { |
| if (monitor.isCanceled()) { |
| throw new OperationCanceledException(); |
| } |
| try { |
| c = reader.read(); |
| if (c == -1) { |
| reader = null; |
| break; |
| } |
| } catch (IOException e) { |
| reader = null; |
| break; |
| } |
| buffer.append((char) c); |
| } |
| } |
| |
| public CharSequence subSequence(int start, int end) { |
| if (end > length || end < 0 || start < 0 || start > end) { |
| throw new IndexOutOfBoundsException(); |
| } |
| if (end > buffer.length()) { |
| fill(end - 1); |
| } |
| if (end <= buffer.length()) { |
| return buffer.subSequence(start, end); |
| } |
| StringBuilder buf = new StringBuilder(end - start); |
| for (int x = start; x < end; ++x) { |
| buf.append(charAt(x)); |
| } |
| return buf; |
| } |
| } |