122 lines
4.0 KiB
Java
122 lines
4.0 KiB
Java
package org.thoughtcrime.securesms.util;
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/*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership.
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* The ASF licenses this file to You under the Apache License, Version 2.0
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* (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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import java.io.FilterInputStream;
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import java.io.IOException;
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import java.io.InputStream;
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import org.session.libsession.utilities.Util;
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/**
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* An input stream, which limits its data size. This stream is
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* used, if the content length is unknown.
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*/
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public class LimitedInputStream extends FilterInputStream {
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/**
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* The maximum size of an item, in bytes.
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*/
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private long sizeMax;
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/**
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* The current number of bytes.
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*/
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private long count;
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/**
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* Whether this stream is already closed.
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*/
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private boolean closed;
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/**
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* Creates a new instance.
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* @param pIn The input stream, which shall be limited.
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* @param pSizeMax The limit; no more than this number of bytes
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* shall be returned by the source stream.
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*/
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public LimitedInputStream(InputStream pIn, long pSizeMax) {
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super(pIn);
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sizeMax = pSizeMax;
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}
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/**
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* Reads the next byte of data from this input stream. The value
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* byte is returned as an <code>int</code> in the range
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* <code>0</code> to <code>255</code>. If no byte is available
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* because the end of the stream has been reached, the value
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* <code>-1</code> is returned. This method blocks until input data
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* is available, the end of the stream is detected, or an exception
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* is thrown.
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*
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* This method
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* simply performs <code>in.read()</code> and returns the result.
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*
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* @return the next byte of data, or <code>-1</code> if the end of the
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* stream is reached.
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* @exception IOException if an I/O error occurs.
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* @see java.io.FilterInputStream#in
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*/
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public int read() throws IOException {
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if (count >= sizeMax) return -1;
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int res = super.read();
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if (res != -1) {
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count++;
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}
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return res;
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}
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/**
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* Reads up to <code>len</code> bytes of data from this input stream
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* into an array of bytes. If <code>len</code> is not zero, the method
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* blocks until some input is available; otherwise, no
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* bytes are read and <code>0</code> is returned.
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*
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* This method simply performs <code>in.read(b, off, len)</code>
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* and returns the result.
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*
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* @param b the buffer into which the data is read.
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* @param off The start offset in the destination array
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* <code>b</code>.
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* @param len the maximum number of bytes read.
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* @return the total number of bytes read into the buffer, or
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* <code>-1</code> if there is no more data because the end of
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* the stream has been reached.
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* @exception NullPointerException If <code>b</code> is <code>null</code>.
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* @exception IndexOutOfBoundsException If <code>off</code> is negative,
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* <code>len</code> is negative, or <code>len</code> is greater than
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* <code>b.length - off</code>
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* @exception IOException if an I/O error occurs.
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* @see java.io.FilterInputStream#in
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*/
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public int read(byte[] b, int off, int len) throws IOException {
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if (count >= sizeMax) return -1;
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long correctLength = Math.min(len, sizeMax - count);
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int res = super.read(b, off, Util.toIntExact(correctLength));
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if (res > 0) {
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count += res;
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}
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return res;
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}
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} |