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COSC_3P95_Assignment_2
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hashing

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Brett 2023-11-14 01:34:56 -05:00
parent 8d1936a368
commit 75f03f181b
1 changed files with 32 additions and 8 deletions
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src/shared/FileHeader.java
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@ -4,7 +4,9 @@ import client.Client;
import net.jpountz.lz4.LZ4Compressor; import net.jpountz.lz4.LZ4Compressor;
import net.jpountz.lz4.LZ4Factory; import net.jpountz.lz4.LZ4Factory;
import net.jpountz.lz4.LZ4FastDecompressor; import net.jpountz.lz4.LZ4FastDecompressor;
import net.jpountz.lz4.LZ4SafeDecompressor; import net.jpountz.xxhash.StreamingXXHash64;
import net.jpountz.xxhash.XXHash64;
import net.jpountz.xxhash.XXHashFactory;
import java.io.*; import java.io.*;
import java.nio.file.Files; import java.nio.file.Files;
@ -12,11 +14,16 @@ import java.nio.file.Paths;
public class FileHeader { public class FileHeader {
public static final int READER_SIZE = 8192; private static final int READER_SIZE = 8192;
private static final LZ4Factory factory = LZ4Factory.fastestInstance(); private static final LZ4Factory LZ_FACTORY = LZ4Factory.fastestInstance();
private static final LZ4Compressor compressor = factory.highCompressor(); private static final LZ4Compressor COMPRESSOR = LZ_FACTORY.highCompressor();
private static final LZ4FastDecompressor decompressor = factory.fastDecompressor(); private static final LZ4FastDecompressor DECOMPRESSOR = LZ_FACTORY.fastDecompressor();
private static final XXHashFactory XX_HASH_FACTORY = XXHashFactory.fastestInstance();
private static final XXHash64 HASH_64 = XX_HASH_FACTORY.hash64();
private static final long SEED = 691;
public enum COMMAND { public enum COMMAND {
WRITE((byte) 1); WRITE((byte) 1);
@ -49,6 +56,7 @@ public class FileHeader {
writer.writeByte(COMMAND.WRITE.type); writer.writeByte(COMMAND.WRITE.type);
writer.writeUTF(relative_path); writer.writeUTF(relative_path);
StreamingXXHash64 streamHash = XX_HASH_FACTORY.newStreamingHash64(SEED);
while (reader.available() > 0) { while (reader.available() > 0) {
// read / write files in chunks // read / write files in chunks
int read = Integer.min(reader.available(), READER_SIZE); int read = Integer.min(reader.available(), READER_SIZE);
@ -58,19 +66,25 @@ public class FileHeader {
if (amount <= 0) if (amount <= 0)
break; break;
// create a checksum for this chunk + update the overall checksum
streamHash.update(bytes, 0, amount);
long hash = HASH_64.hash(bytes, 0, amount, SEED);
// apply compression // apply compression
int maxCompressedLength = compressor.maxCompressedLength(bytes.length); int maxCompressedLength = COMPRESSOR.maxCompressedLength(bytes.length);
byte[] compressed = new byte[maxCompressedLength]; byte[] compressed = new byte[maxCompressedLength];
int compressedLength = compressor.compress(bytes, 0, bytes.length, compressed, 0, maxCompressedLength); int compressedLength = COMPRESSOR.compress(bytes, 0, bytes.length, compressed, 0, maxCompressedLength);
System.out.println("Writing " + compressedLength + " bytes"); System.out.println("Writing " + compressedLength + " bytes");
writer.writeInt(amount); writer.writeInt(amount);
writer.writeInt(compressedLength); writer.writeInt(compressedLength);
writer.writeLong(hash);
writer.write(compressed, 0, compressedLength); writer.write(compressed, 0, compressedLength);
writer.flush(); writer.flush();
} }
reader.close(); reader.close();
writer.writeInt(0); writer.writeInt(0);
writer.writeLong(streamHash.getValue());
writer.flush(); writer.flush();
} catch (Exception e) { } catch (Exception e) {
ExceptionLogger.log(e); ExceptionLogger.log(e);
@ -93,17 +107,27 @@ public class FileHeader {
DataOutputStream writer = new DataOutputStream(new BufferedOutputStream(Files.newOutputStream(Paths.get(path)))); DataOutputStream writer = new DataOutputStream(new BufferedOutputStream(Files.newOutputStream(Paths.get(path))));
int uncompressed_size = 0; int uncompressed_size = 0;
StreamingXXHash64 computedStreamHash = XX_HASH_FACTORY.newStreamingHash64(SEED);
while ((uncompressed_size = reader.readInt()) > 0) { while ((uncompressed_size = reader.readInt()) > 0) {
int compressed_size = reader.readInt(); int compressed_size = reader.readInt();
long hash = reader.readLong();
byte[] data = new byte[compressed_size]; byte[] data = new byte[compressed_size];
int amount = reader.read(data, 0, compressed_size); int amount = reader.read(data, 0, compressed_size);
byte[] restored = new byte[uncompressed_size]; byte[] restored = new byte[uncompressed_size];
int len = DECOMPRESSOR.decompress(data, 0, restored, 0, uncompressed_size);
int len = decompressor.decompress(data, 0, restored, 0, uncompressed_size); long computedHash = HASH_64.hash(restored, 0, uncompressed_size, SEED);
computedStreamHash.update(restored, 0, uncompressed_size);
if (hash != computedHash)
throw new RuntimeException(hash + " HELP! " + computedHash);
writer.write(restored, 0, uncompressed_size); writer.write(restored, 0, uncompressed_size);
} }
long streamHash = reader.readLong();
if (computedStreamHash.getValue() != streamHash)
throw new RuntimeException("HELP 22");
writer.flush(); writer.flush();
writer.close(); writer.close();
} catch (Exception e){ } catch (Exception e){