| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package org.apache.commons.io.input; |
| |
| import static org.apache.commons.io.IOUtils.EOF; |
| |
| import java.io.Reader; |
| import java.io.Serializable; |
| |
| /** |
| * {@link Reader} implementation that can read from String, StringBuffer, |
| * StringBuilder or CharBuffer. |
| * <p> |
| * <strong>Note:</strong> Supports {@link #mark(int)} and {@link #reset()}. |
| * |
| * @version $Id$ |
| * @since 1.4 |
| */ |
| public class CharSequenceReader extends Reader implements Serializable { |
| |
| private static final long serialVersionUID = 3724187752191401220L; |
| private final CharSequence charSequence; |
| private int idx; |
| private int mark; |
| |
| /** |
| * Construct a new instance with the specified character sequence. |
| * |
| * @param charSequence The character sequence, may be {@code null} |
| */ |
| public CharSequenceReader(final CharSequence charSequence) { |
| this.charSequence = charSequence != null ? charSequence : ""; |
| } |
| |
| /** |
| * Close resets the file back to the start and removes any marked position. |
| */ |
| @Override |
| public void close() { |
| idx = 0; |
| mark = 0; |
| } |
| |
| /** |
| * Mark the current position. |
| * |
| * @param readAheadLimit ignored |
| */ |
| @Override |
| public void mark(final int readAheadLimit) { |
| mark = idx; |
| } |
| |
| /** |
| * Mark is supported (returns true). |
| * |
| * @return {@code true} |
| */ |
| @Override |
| public boolean markSupported() { |
| return true; |
| } |
| |
| /** |
| * Read a single character. |
| * |
| * @return the next character from the character sequence |
| * or -1 if the end has been reached. |
| */ |
| @Override |
| public int read() { |
| if (idx >= charSequence.length()) { |
| return EOF; |
| } else { |
| return charSequence.charAt(idx++); |
| } |
| } |
| |
| /** |
| * Read the sepcified number of characters into the array. |
| * |
| * @param array The array to store the characters in |
| * @param offset The starting position in the array to store |
| * @param length The maximum number of characters to read |
| * @return The number of characters read or -1 if there are |
| * no more |
| */ |
| @Override |
| public int read(final char[] array, final int offset, final int length) { |
| if (idx >= charSequence.length()) { |
| return EOF; |
| } |
| if (array == null) { |
| throw new NullPointerException("Character array is missing"); |
| } |
| if (length < 0 || offset < 0 || offset + length > array.length) { |
| throw new IndexOutOfBoundsException("Array Size=" + array.length + |
| ", offset=" + offset + ", length=" + length); |
| } |
| int count = 0; |
| for (int i = 0; i < length; i++) { |
| final int c = read(); |
| if (c == EOF) { |
| return count; |
| } |
| array[offset + i] = (char)c; |
| count++; |
| } |
| return count; |
| } |
| |
| /** |
| * Reset the reader to the last marked position (or the beginning if |
| * mark has not been called). |
| */ |
| @Override |
| public void reset() { |
| idx = mark; |
| } |
| |
| /** |
| * Skip the specified number of characters. |
| * |
| * @param n The number of characters to skip |
| * @return The actual number of characters skipped |
| */ |
| @Override |
| public long skip(final long n) { |
| if (n < 0) { |
| throw new IllegalArgumentException( |
| "Number of characters to skip is less than zero: " + n); |
| } |
| if (idx >= charSequence.length()) { |
| return EOF; |
| } |
| final int dest = (int)Math.min(charSequence.length(), idx + n); |
| final int count = dest - idx; |
| idx = dest; |
| return count; |
| } |
| |
| /** |
| * Return a String representation of the underlying |
| * character sequence. |
| * |
| * @return The contents of the character sequence |
| */ |
| @Override |
| public String toString() { |
| return charSequence.toString(); |
| } |
| } |