| /* |
| * 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 static org.apache.commons.codec.binary.BaseNCodec.EOF; |
| |
| import java.io.FilterInputStream; |
| import java.io.IOException; |
| import java.io.InputStream; |
| import java.util.Objects; |
| |
| import org.apache.commons.codec.binary.BaseNCodec.Context; |
| |
| /** |
| * Abstract superclass for Base-N input streams. |
| * |
| * @since 1.5 |
| */ |
| public class BaseNCodecInputStream extends FilterInputStream { |
| |
| private final BaseNCodec baseNCodec; |
| |
| private final boolean doEncode; |
| |
| private final byte[] singleByte = new byte[1]; |
| |
| private final Context context = new Context(); |
| |
| protected BaseNCodecInputStream(final InputStream input, final BaseNCodec baseNCodec, final boolean doEncode) { |
| super(input); |
| this.doEncode = doEncode; |
| this.baseNCodec = baseNCodec; |
| } |
| |
| /** |
| * {@inheritDoc} |
| * |
| * @return {@code 0} if the {@link InputStream} has reached {@code EOF}, |
| * {@code 1} otherwise |
| * @since 1.7 |
| */ |
| @Override |
| public int available() throws IOException { |
| // Note: the logic is similar to the InflaterInputStream: |
| // as long as we have not reached EOF, indicate that there is more |
| // data available. As we do not know for sure how much data is left, |
| // just return 1 as a safe guess. |
| |
| return context.eof ? 0 : 1; |
| } |
| |
| /** |
| * Returns true if decoding behavior is strict. Decoding will raise an |
| * {@link IllegalArgumentException} if trailing bits are not part of a valid encoding. |
| * |
| * <p>The default is false for lenient encoding. Decoding will compose trailing bits |
| * into 8-bit bytes and discard the remainder. |
| * |
| * @return true if using strict decoding |
| * @since 1.15 |
| */ |
| public boolean isStrictDecoding() { |
| return baseNCodec.isStrictDecoding(); |
| } |
| |
| /** |
| * Marks the current position in this input stream. |
| * <p>The {@link #mark} method of {@link BaseNCodecInputStream} does nothing.</p> |
| * |
| * @param readLimit the maximum limit of bytes that can be read before the mark position becomes invalid. |
| * @see #markSupported() |
| * @since 1.7 |
| */ |
| @Override |
| public synchronized void mark(final int readLimit) { |
| // noop |
| } |
| |
| /** |
| * {@inheritDoc} |
| * |
| * @return Always returns {@code false} |
| */ |
| @Override |
| public boolean markSupported() { |
| return false; // not an easy job to support marks |
| } |
| |
| /** |
| * Reads one {@code byte} from this input stream. |
| * |
| * @return the byte as an integer in the range 0 to 255. Returns -1 if EOF has been reached. |
| * @throws IOException |
| * if an I/O error occurs. |
| */ |
| @Override |
| public int read() throws IOException { |
| int r = read(singleByte, 0, 1); |
| while (r == 0) { |
| r = read(singleByte, 0, 1); |
| } |
| if (r > 0) { |
| final byte b = singleByte[0]; |
| return b < 0 ? 256 + b : b; |
| } |
| return EOF; |
| } |
| |
| /** |
| * Attempts to read {@code len} bytes into the specified {@code b} array starting at {@code offset} |
| * from this InputStream. |
| * |
| * @param array |
| * destination byte array |
| * @param offset |
| * where to start writing the bytes |
| * @param len |
| * maximum number of bytes to read |
| * |
| * @return number of bytes read |
| * @throws IOException |
| * if an I/O error occurs. |
| * @throws NullPointerException |
| * if the byte array parameter is null |
| * @throws IndexOutOfBoundsException |
| * if offset, len or buffer size are invalid |
| */ |
| @Override |
| public int read(final byte array[], final int offset, final int len) throws IOException { |
| Objects.requireNonNull(array, "array"); |
| if (offset < 0 || len < 0) { |
| throw new IndexOutOfBoundsException(); |
| } |
| if (offset > array.length || offset + len > array.length) { |
| throw new IndexOutOfBoundsException(); |
| } |
| if (len == 0) { |
| return 0; |
| } |
| int readLen = 0; |
| /* |
| Rationale for while-loop on (readLen == 0): |
| ----- |
| Base32.readResults() usually returns > 0 or EOF (-1). In the |
| rare case where it returns 0, we just keep trying. |
| |
| This is essentially an undocumented contract for InputStream |
| implementors that want their code to work properly with |
| java.io.InputStreamReader, since the latter hates it when |
| InputStream.read(byte[]) returns a zero. Unfortunately our |
| readResults() call must return 0 if a large amount of the data |
| being decoded was non-base32, so this while-loop enables proper |
| interop with InputStreamReader for that scenario. |
| ----- |
| This is a fix for CODEC-101 |
| */ |
| while (readLen == 0) { |
| if (!baseNCodec.hasData(context)) { |
| final byte[] buf = new byte[doEncode ? 4096 : 8192]; |
| final int c = in.read(buf); |
| if (doEncode) { |
| baseNCodec.encode(buf, 0, c, context); |
| } else { |
| baseNCodec.decode(buf, 0, c, context); |
| } |
| } |
| readLen = baseNCodec.readResults(array, offset, len, context); |
| } |
| return readLen; |
| } |
| |
| /** |
| * Repositions this stream to the position at the time the mark method was last called on this input stream. |
| * <p> |
| * The {@link #reset} method of {@link BaseNCodecInputStream} does nothing except throw an {@link IOException}. |
| * |
| * @throws IOException if this method is invoked |
| * @since 1.7 |
| */ |
| @Override |
| public synchronized void reset() throws IOException { |
| throw new IOException("mark/reset not supported"); |
| } |
| |
| /** |
| * {@inheritDoc} |
| * |
| * @throws IllegalArgumentException if the provided skip length is negative |
| * @since 1.7 |
| */ |
| @Override |
| public long skip(final long n) throws IOException { |
| if (n < 0) { |
| throw new IllegalArgumentException("Negative skip length: " + n); |
| } |
| |
| // skip in chunks of 512 bytes |
| final byte[] b = new byte[512]; |
| long todo = n; |
| |
| while (todo > 0) { |
| int len = (int) Math.min(b.length, todo); |
| len = this.read(b, 0, len); |
| if (len == EOF) { |
| break; |
| } |
| todo -= len; |
| } |
| |
| return n - todo; |
| } |
| } |