109 lines
3.6 KiB
Java
109 lines
3.6 KiB
Java
/*
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Copyright 2019-2022 Dmitry Isaenko
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This file is part of libKonogonka.
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libKonogonka is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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libKonogonka is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with libKonogonka. If not, see <https://www.gnu.org/licenses/>.
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*/
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package libKonogonka.ctraes;
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import libKonogonka.IProducer;
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import java.io.BufferedInputStream;
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import java.io.File;
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import java.nio.file.Files;
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public class InFileStreamProducer implements IProducer {
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private boolean encrypted;
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private final File file;
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private final long initialOffset;
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private final long subOffset;
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private AesCtrDecryptForMediaBlocks decryptor;
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private long mediaStartOffset;
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private long mediaEndOffset;
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public InFileStreamProducer(File file){
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this.file = file;
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this.initialOffset = 0;
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this.subOffset = 0;
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}
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public InFileStreamProducer(File file, long subOffset){
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this.file = file;
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this.initialOffset = 0;
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this.subOffset = subOffset;
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}
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public InFileStreamProducer(
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File file,
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long initialOffset,
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long subOffset,
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AesCtrDecryptForMediaBlocks decryptor,
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long mediaStartOffset,
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long mediaEndOffset){
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this.encrypted = (decryptor != null);
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this.file = file;
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this.initialOffset = initialOffset;
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this.subOffset = subOffset;
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this.decryptor = decryptor;
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this.mediaStartOffset = mediaStartOffset;
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this.mediaEndOffset = mediaEndOffset;
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}
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@Override
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public BufferedInputStream produce() throws Exception{
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if (encrypted)
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return produceAesCtr();
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return produceNotEncrypted();
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}
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private AesCtrBufferedInputStream produceAesCtr() throws Exception{
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decryptor.reset();
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AesCtrBufferedInputStream stream = new AesCtrBufferedInputStream(
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decryptor,
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initialOffset,
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mediaStartOffset,
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mediaEndOffset,
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Files.newInputStream(file.toPath()),
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Files.size(file.toPath())); // Files.size(file.toPath())-initialOffset); ?
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skipBytesTillBeginning(stream, subOffset);
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return stream;
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}
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private BufferedInputStream produceNotEncrypted() throws Exception{
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BufferedInputStream stream = new BufferedInputStream(Files.newInputStream(file.toPath()));
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skipBytesTillBeginning(stream, subOffset);
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return stream;
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}
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@Override
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public InFileStreamProducer getSuccessor(long subOffset){
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return new InFileStreamProducer(file, initialOffset, subOffset, decryptor, mediaStartOffset, mediaEndOffset);
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}
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@Override
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public boolean isEncrypted() {
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return encrypted;
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}
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private void skipBytesTillBeginning(BufferedInputStream stream, long size) throws Exception{
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long mustSkip = size;
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long skipped = 0;
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while (mustSkip > 0){
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skipped += stream.skip(mustSkip);
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mustSkip = size - skipped;
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}
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}
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@Override
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public File getFile(){ return file; }
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@Override
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public String toString(){
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return file.getName();
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}
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}
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