retrofit SimpleDataStructure over SHA1Hash

core/java/src/net/i2p/crypto/SHA1Hash.java

@@ -14,8 +14,7 @@ import java.io.InputStream;
 import java.io.OutputStream;
 
 import net.i2p.data.DataFormatException;
-import net.i2p.data.DataHelper;
-import net.i2p.data.DataStructureImpl;
+import net.i2p.data.SimpleDataStructure;
 
 /**
  * Because DSAEngine was abusing Hash for 20-byte hashes
@@ -23,44 +22,31 @@ import net.i2p.data.DataStructureImpl;
  * @since 0.8.1
  * @author zzz
  */
-public class SHA1Hash extends DataStructureImpl {
-    private byte[] _data;
+public class SHA1Hash extends SimpleDataStructure {
     private int _cachedHashCode;
 
     public final static int HASH_LENGTH = SHA1.HASH_LENGTH;
     
     /** @throws IllegalArgumentException if data is not 20 bytes (null is ok) */
     public SHA1Hash(byte data[]) {
-        setData(data);
+        super(data);
     }
 
-    public byte[] getData() {
-        return _data;
+    public int length() {
+        return HASH_LENGTH;
     }
 
     /** @throws IllegalArgumentException if data is not 20 bytes (null is ok) */
+    @Override
     public void setData(byte[] data) {
-        // FIXME DSAEngine uses a SHA-1 "Hash" as parameters and return values!
-        if (data != null && data.length != HASH_LENGTH)
-            throw new IllegalArgumentException("Hash must be 20 bytes");
-        _data = data;
-        _cachedHashCode = calcHashCode();
-    }
-
-    /** @throws IOException always */
-    public void readBytes(InputStream in) throws DataFormatException, IOException {
-        throw new IOException("unimplemented");
-    }
-    
-    /** @throws IOException always */
-    public void writeBytes(OutputStream out) throws DataFormatException, IOException {
-        throw new IOException("unimplemented");
+        super.setData(data);
+        _cachedHashCode = super.hashCode();
     }
 
     @Override
-    public boolean equals(Object obj) {
-        if ((obj == null) || !(obj instanceof SHA1Hash)) return false;
-        return DataHelper.eq(_data, ((SHA1Hash) obj)._data);
+    public void readBytes(InputStream in) throws DataFormatException, IOException {
+        super.readBytes(in);
+        _cachedHashCode = super.hashCode();
     }
     
     /** a Hash is a hash, so just use the first 4 bytes for speed */
@@ -68,14 +54,4 @@ public class SHA1Hash extends DataStructureImpl {
     public int hashCode() {
         return _cachedHashCode;
     }
-
-    /** a Hash is a hash, so just use the first 4 bytes for speed */
-    private int calcHashCode() {
-        int rv = 0;
-        if (_data != null) {
-            for (int i = 0; i < 4; i++)
-                rv ^= (_data[i] << (i*8));
-        }
-        return rv;
-    }
 }