1 files changed, 100 insertions, 0 deletions
diff --git a/src/main/java/org/openslx/imagemaster/util/Hash.java b/src/main/java/org/openslx/imagemaster/util/Hash.java
new file mode 100644
index 0000000..8ac0e5f
--- /dev/null
+++ b/src/main/java/org/openslx/imagemaster/util/Hash.java
@@ -0,0 +1,100 @@
+package org.openslx.imagemaster.util;
+
+import java.security.MessageDigest;
+import java.nio.charset.Charset;
+import java.security.NoSuchAlgorithmException;
+
+public class Hash
+{
+	// Cache of md5 digesters
+	private static final ThreadLocal<MessageDigest> md5hash = new ThreadLocal<MessageDigest>() {
+		@Override
+		public MessageDigest initialValue()
+		{
+			try {
+				return MessageDigest.getInstance( "MD5" );
+			} catch ( NoSuchAlgorithmException e ) {
+				e.printStackTrace();
+				System.exit(1);
+				return null;
+			}
+		}
+	};
+	// Cache of sha256 digesters
+	private static final ThreadLocal<MessageDigest> sha256hash = new ThreadLocal<MessageDigest>() {
+		@Override
+		public MessageDigest initialValue()
+		{
+			try {
+				return MessageDigest.getInstance( "SHA-256" );
+			} catch ( NoSuchAlgorithmException e ) {
+				e.printStackTrace();
+				System.exit(1);
+				return null;
+			}
+		}
+	};
+	// Cache of sha512 digesters
+	private static final ThreadLocal<MessageDigest> sha512hash = new ThreadLocal<MessageDigest>() {
+		@Override
+		public MessageDigest initialValue()
+		{
+			try {
+				return MessageDigest.getInstance( "SHA-512" );
+			} catch ( NoSuchAlgorithmException e ) {
+				e.printStackTrace();
+				System.exit(1);
+				return null;
+			}
+		}
+	};
+	// For converting to hex string
+	private static final char[] HEX_CHARS = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };
+	// Constant
+	private static final Charset UTF8 = Charset.forName( "UTF-8" );
+
+	// MD5
+	
+	public static String md5( final byte[] bytes )
+	{
+		return toHexString( md5hash.get().digest( bytes ) );
+	}
+	
+	public static String md5( final String text )
+	{
+		return md5( text.getBytes( UTF8 ));
+	}
+	
+	// SHA-256
+	
+	public static String sha256( final byte[] bytes )
+	{
+		return toHexString( sha256hash.get().digest( bytes ) );
+	}
+	
+	public static String sha256( final String text )
+	{
+		return sha256( text.getBytes( UTF8 ));
+	}
+	
+	// SHA-512
+	
+	public static MessageDigest getSha512Digest()
+	{
+		return sha512hash.get();
+	}
+
+	// Helper
+	
+	private static String toHexString( final byte[] bytes )
+	{
+		final char[] hexChars = new char[bytes.length * 2];
+		for ( int j = 0; j < bytes.length; ++j ) {
+			final int v = bytes[j] & 0xFF;
+			hexChars[j * 2] = HEX_CHARS[v >>> 4];
+			hexChars[j * 2 + 1] = HEX_CHARS[v & 0x0F];
+		}
+		return new String( hexChars );
+	}
+
+}