| // CHECKSTYLE_OFF: Copyrighted to the Android Open Source Project. |
| /* |
| * 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. |
| */ |
| // CHECKSTYLE_ON |
| |
| package java.io; |
| |
| /** |
| * A specialized {@link InputStream } for reading the contents of a byte array. |
| * |
| * @see ByteArrayOutputStream |
| */ |
| public class ByteArrayInputStream extends InputStream { |
| /** |
| * The {@code byte} array containing the bytes to stream over. |
| */ |
| protected byte[] buf; |
| |
| /** |
| * The current position within the byte array. |
| */ |
| protected int pos; |
| |
| /** |
| * The current mark position. Initially set to 0 or the <code>offset</code> |
| * parameter within the constructor. |
| */ |
| protected int mark; |
| |
| /** |
| * The total number of bytes initially available in the byte array |
| * {@code buf}. |
| */ |
| protected int count; |
| |
| /** |
| * Constructs a new {@code ByteArrayInputStream} on the byte array |
| * {@code buf}. |
| * |
| * @param buf |
| * the byte array to stream over. |
| */ |
| public ByteArrayInputStream(byte[] buf) { |
| this.mark = 0; |
| this.buf = buf; |
| this.count = buf.length; |
| } |
| |
| /** |
| * Constructs a new {@code ByteArrayInputStream} on the byte array |
| * {@code buf} with the initial position set to {@code offset} and the |
| * number of bytes available set to {@code offset} + {@code length}. |
| * |
| * @param buf |
| * the byte array to stream over. |
| * @param offset |
| * the initial position in {@code buf} to start streaming from. |
| * @param length |
| * the number of bytes available for streaming. |
| */ |
| public ByteArrayInputStream(byte[] buf, int offset, int length) { |
| this.buf = buf; |
| pos = offset; |
| mark = offset; |
| count = offset + length > buf.length ? buf.length : offset + length; |
| } |
| |
| /** |
| * Returns the number of remaining bytes. |
| * |
| * @return {@code count - pos} |
| */ |
| @Override |
| public int available() { |
| return count - pos; |
| } |
| |
| /** |
| * Closes this stream and frees resources associated with this stream. |
| * |
| * @throws IOException |
| * if an I/O error occurs while closing this stream. |
| */ |
| @Override |
| public void close() throws IOException { |
| // Do nothing on close, this matches JDK behavior. |
| } |
| |
| /** |
| * Sets a mark position in this ByteArrayInputStream. The parameter |
| * {@code readlimit} is ignored. Sending {@code reset()} will reposition the |
| * stream back to the marked position. |
| * |
| * @param readlimit |
| * ignored. |
| * @see #markSupported() |
| * @see #reset() |
| */ |
| @Override |
| public void mark(int readlimit) { |
| mark = pos; |
| } |
| |
| /** |
| * Indicates whether this stream supports the {@code mark()} and |
| * {@code reset()} methods. Returns {@code true} since this class supports |
| * these methods. |
| * |
| * @return always {@code true}. |
| * @see #mark(int) |
| * @see #reset() |
| */ |
| @Override |
| public boolean markSupported() { |
| return true; |
| } |
| |
| /** |
| * Reads a single byte from the source byte array and returns it as an |
| * integer in the range from 0 to 255. Returns -1 if the end of the source |
| * array has been reached. |
| * |
| * @return the byte read or -1 if the end of this stream has been reached. |
| */ |
| @Override |
| public int read() { |
| return pos < count ? buf[pos++] & 0xFF : -1; |
| } |
| |
| @Override public int read(byte[] buffer, int byteOffset, int byteCount) { |
| IOUtils.checkOffsetAndCount(buffer, byteOffset, byteCount); |
| |
| // Are there any bytes available? |
| if (this.pos >= this.count) { |
| return -1; |
| } |
| if (byteCount == 0) { |
| return 0; |
| } |
| |
| int copylen = this.count - pos < byteCount ? this.count - pos : byteCount; |
| System.arraycopy(this.buf, pos, buffer, byteOffset, copylen); |
| pos += copylen; |
| return copylen; |
| } |
| |
| /** |
| * Resets this stream to the last marked location. This implementation |
| * resets the position to either the marked position, the start position |
| * supplied in the constructor or 0 if neither has been provided. |
| * |
| * @see #mark(int) |
| */ |
| @Override |
| public void reset() { |
| pos = mark; |
| } |
| |
| /** |
| * Skips {@code byteCount} bytes in this InputStream. Subsequent |
| * calls to {@code read} will not return these bytes unless {@code reset} is |
| * used. This implementation skips {@code byteCount} number of bytes in the |
| * target stream. It does nothing and returns 0 if {@code byteCount} is negative. |
| * |
| * @return the number of bytes actually skipped. |
| */ |
| @Override |
| public long skip(long byteCount) { |
| if (byteCount <= 0) { |
| return 0; |
| } |
| int temp = pos; |
| pos = this.count - pos < byteCount ? this.count : (int) (pos + byteCount); |
| return pos - temp; |
| } |
| } |