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/*
 * 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.codec.binary;

import java.io.InputStream;

import org.apache.commons.codec.CodecPolicy;

/**
 * Provides Base64 encoding and decoding in a streaming fashion (unlimited size). When encoding the default lineLength
 * is 76 characters and the default lineEnding is CRLF, but these can be overridden by using the appropriate
 * constructor.
 * 

* The default behavior of the Base64InputStream is to DECODE, whereas the default behavior of the Base64OutputStream * is to ENCODE, but this behavior can be overridden by using a different constructor. *

*

* This class implements section 6.8. Base64 Content-Transfer-Encoding from RFC 2045 Multipurpose * Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies by Freed and Borenstein. *

*

* Since this class operates directly on byte streams, and not character streams, it is hard-coded to only encode/decode * character encodings which are compatible with the lower 127 ASCII chart (ISO-8859-1, Windows-1252, UTF-8, etc). *

*

* You can set the decoding behavior when the input bytes contain leftover trailing bits that cannot be created by a valid * encoding. These can be bits that are unused from the final character or entire characters. The default mode is * lenient decoding. *

*
    *
  • Lenient: Any trailing bits are composed into 8-bit bytes where possible. The remainder are discarded. *
  • Strict: The decoding will raise an {@link IllegalArgumentException} if trailing bits are not part of a valid * encoding. Any unused bits from the final character must be zero. Impossible counts of entire final characters are not * allowed. *
*

* When strict decoding is enabled it is expected that the decoded bytes will be re-encoded to a byte array that matches * the original, i.e. no changes occur on the final character. This requires that the input bytes use the same padding * and alphabet as the encoder. *

* @see RFC 2045 * @since 1.4 */ public class Base64InputStream extends BaseNCodecInputStream { /** * Creates a Base64InputStream such that all data read is Base64-decoded from the original provided InputStream. * * @param in * InputStream to wrap. */ public Base64InputStream(final InputStream in) { this(in, false); } /** * Creates a Base64InputStream such that all data read is either Base64-encoded or Base64-decoded from the original * provided InputStream. * * @param in * InputStream to wrap. * @param doEncode * true if we should encode all data read from us, false if we should decode. */ public Base64InputStream(final InputStream in, final boolean doEncode) { super(in, new Base64(false), doEncode); } /** * Creates a Base64InputStream such that all data read is either Base64-encoded or Base64-decoded from the original * provided InputStream. * * @param in * InputStream to wrap. * @param doEncode * true if we should encode all data read from us, false if we should decode. * @param lineLength * If doEncode is true, each line of encoded data will contain lineLength characters (rounded down to * nearest multiple of 4). If lineLength <= 0, the encoded data is not divided into lines. If doEncode * is false, lineLength is ignored. * @param lineSeparator * If doEncode is true, each line of encoded data will be terminated with this byte sequence (e.g. \r\n). * If lineLength <= 0, the lineSeparator is not used. If doEncode is false lineSeparator is ignored. */ public Base64InputStream(final InputStream in, final boolean doEncode, final int lineLength, final byte[] lineSeparator) { super(in, new Base64(lineLength, lineSeparator), doEncode); } /** * Creates a Base64InputStream such that all data read is either Base64-encoded or Base64-decoded from the original * provided InputStream. * * @param in * InputStream to wrap. * @param doEncode * true if we should encode all data read from us, false if we should decode. * @param lineLength * If doEncode is true, each line of encoded data will contain lineLength characters (rounded down to * nearest multiple of 4). If lineLength <= 0, the encoded data is not divided into lines. If doEncode * is false, lineLength is ignored. * @param lineSeparator * If doEncode is true, each line of encoded data will be terminated with this byte sequence (e.g. \r\n). * If lineLength <= 0, the lineSeparator is not used. If doEncode is false lineSeparator is ignored. * @param decodingPolicy The decoding policy. * @since 1.15 */ public Base64InputStream(final InputStream in, final boolean doEncode, final int lineLength, final byte[] lineSeparator, final CodecPolicy decodingPolicy) { super(in, new Base64(lineLength, lineSeparator, false, decodingPolicy), doEncode); } }




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