| /* |
| * 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.axiom.util.base64; |
| |
| import java.io.IOException; |
| import java.io.OutputStream; |
| |
| /** |
| * Base class for {@link OutputStream} implementations that encode data in base64. |
| */ |
| public abstract class AbstractBase64EncodingOutputStream extends OutputStream { |
| private final boolean ignoreFlush; |
| private final byte[] in = new byte[3]; |
| private final byte[] out = new byte[4]; |
| private int rest; // Number of bytes remaining in the inBuffer |
| private boolean completed; |
| |
| /** |
| * Constructor. |
| * |
| * @param ignoreFlush |
| * Specifies if calls to {@link #flush()} should be ignored. Setting this to |
| * <code>true</code> is particular useful in conjunction with |
| * {@code DataHandler.writeTo(OutputStream)}: that method may call {@link #flush()} |
| * after writing the data, but the call to {@code DataHandler.writeTo(OutputStream)} |
| * must be followed by a call to {@link #close()} or {@link #complete()} which would |
| * then output a single chunk with a few bytes. In some cases this may be |
| * inconvenient. |
| */ |
| public AbstractBase64EncodingOutputStream(boolean ignoreFlush) { |
| this.ignoreFlush = ignoreFlush; |
| } |
| |
| /** |
| * Default constructor. This constructor does the same as |
| * {@link #AbstractBase64EncodingOutputStream(boolean)} with <code>ignoreFlush</code> set to |
| * <code>false</code>. |
| */ |
| public AbstractBase64EncodingOutputStream() { |
| this(false); |
| } |
| |
| @Override |
| public final void write(byte[] b, int off, int len) throws IOException { |
| if (completed) { |
| throw new IOException("Attempt to write data after base64 encoding has been completed"); |
| } |
| if (rest > 0) { |
| while (len > 0 && rest < 3) { |
| in[rest++] = b[off++]; |
| len--; |
| } |
| if (rest == 3) { |
| encode(in, 0, 3); |
| rest = 0; |
| } |
| } |
| while (len >= 3) { |
| encode(b, off, 3); |
| off += 3; |
| len -= 3; |
| } |
| while (len > 0) { |
| in[rest++] = b[off++]; |
| len--; |
| } |
| } |
| |
| @Override |
| public final void write(int b) throws IOException { |
| in[rest++] = (byte)b; |
| if (rest == 3) { |
| encode(in, 0, 3); |
| rest = 0; |
| } |
| } |
| |
| /** |
| * Write out any pending data, including padding if necessary. |
| * |
| * @throws IOException if an I/O error occurs |
| */ |
| public final void complete() throws IOException { |
| if (!completed) { |
| if (rest > 0) { |
| encode(in, 0, rest); |
| } |
| flushBuffer(); |
| completed = true; |
| } |
| } |
| |
| private void encode(byte[] data, int off, int len) throws IOException { |
| if (len == 1) { |
| int i = data[off] & 0xff; |
| out[0] = Base64Constants.S_BASE64CHAR[i >> 2]; |
| out[1] = Base64Constants.S_BASE64CHAR[(i << 4) & 0x3f]; |
| out[2] = Base64Constants.S_BASE64PAD; |
| out[3] = Base64Constants.S_BASE64PAD; |
| } else if (len == 2) { |
| int i = ((data[off] & 0xff) << 8) + (data[off + 1] & 0xff); |
| out[0] = Base64Constants.S_BASE64CHAR[i >> 10]; |
| out[1] = Base64Constants.S_BASE64CHAR[(i >> 4) & 0x3f]; |
| out[2] = Base64Constants.S_BASE64CHAR[(i << 2) & 0x3f]; |
| out[3] = Base64Constants.S_BASE64PAD; |
| } else { |
| int i = ((data[off] & 0xff) << 16) |
| + ((data[off + 1] & 0xff) << 8) |
| + (data[off + 2] & 0xff); |
| out[0] = Base64Constants.S_BASE64CHAR[i >> 18]; |
| out[1] = Base64Constants.S_BASE64CHAR[(i >> 12) & 0x3f]; |
| out[2] = Base64Constants.S_BASE64CHAR[(i >> 6) & 0x3f]; |
| out[3] = Base64Constants.S_BASE64CHAR[i & 0x3f]; |
| } |
| doWrite(out); |
| } |
| |
| @Override |
| public final void flush() throws IOException { |
| if (!ignoreFlush) { |
| flushBuffer(); |
| doFlush(); |
| } |
| } |
| |
| @Override |
| public final void close() throws IOException { |
| complete(); |
| doClose(); |
| } |
| |
| /** |
| * Write base64 encoded data. If necessary, the implementation should accumulate |
| * the data in a buffer before writing it to the underlying stream. |
| * |
| * @param b a byte array of length 4 |
| * @throws IOException if an I/O error occurs |
| */ |
| protected abstract void doWrite(byte[] b) throws IOException; |
| |
| /** |
| * Write any pending data to the underlying stream, if applicable. |
| * Note that implementations should not flush the underlying stream. |
| * |
| * @throws IOException if an I/O error occurs |
| */ |
| protected abstract void flushBuffer() throws IOException; |
| |
| /** |
| * Flush the underlying stream, if applicable. |
| * |
| * @throws IOException if an I/O error occurs |
| */ |
| protected abstract void doFlush() throws IOException; |
| |
| /** |
| * Close the underlying stream, if applicable. |
| * |
| * @throws IOException if an I/O error occurs |
| */ |
| protected abstract void doClose() throws IOException; |
| } |