Data structures for InfoHash and a shared file

core/src/main/java/com/muwire/core/InfoHash.java

@@ -0,0 +1,75 @@
+package com.muwire.core;
+
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+import java.util.Arrays;
+
+import net.i2p.data.Base32;
+
+public class InfoHash {
+
+	private static final int SIZE = 0x1 << 5;
+	
+	private final byte[] root;
+	private final byte[] hashList;
+	
+	private final int hashCode;
+	
+	public InfoHash(byte[] root, byte[] hashList) {
+		if (root.length != SIZE)
+			throw new IllegalArgumentException("invalid root size "+root.length);
+		if (hashList != null && hashList.length % SIZE != 0) 
+			throw new IllegalArgumentException("invalid hashList size " + hashList.length);
+		this.root = root;
+		this.hashList = hashList;
+		hashCode = root[0] << 24 |
+				root[1] << 16 |
+				root[2] << 8 |
+				root[3];
+	}
+	
+	public InfoHash(byte[] root) {
+		this(root, null);
+	}
+	
+	public InfoHash(String base32) {
+		this(Base32.decode(base32));
+	}
+	
+	public static InfoHash fromHashList(byte []hashList) {
+		try {
+			MessageDigest sha256 = MessageDigest.getInstance("SHA256");
+			byte[] root = sha256.digest(hashList);
+			return new InfoHash(root, hashList);
+		} catch (NoSuchAlgorithmException impossible) {
+			impossible.printStackTrace();
+			System.exit(1);
+		}
+		return null;
+	}
+	
+	public byte[] getRoot() {
+		return root;
+	}
+	
+	public byte[] getHashList() {
+		return hashList;
+	}
+	
+	@Override
+	public int hashCode() {
+		return hashCode;
+	}
+	
+	@Override
+	public boolean equals(Object o) {
+		if (this == o) {
+			return true;
+		}
+		if (!(o instanceof InfoHash)) {
+			return false;
+		}
+		InfoHash other = (InfoHash) o;
+		return Arrays.equals(root, other.root);
+	}
+}

core/src/main/java/com/muwire/core/SharedFile.java

@@ -0,0 +1,23 @@
+package com.muwire.core;
+
+import java.io.File;
+
+public class SharedFile {
+
+	private final File file;
+	private final InfoHash infoHash;
+	
+	public SharedFile(File file, InfoHash infoHash) {
+		this.file = file;
+		this.infoHash = infoHash;
+	}
+
+	public File getFile() {
+		return file;
+	}
+
+	public InfoHash getInfoHash() {
+		return infoHash;
+	}
+	
+}