Add SCRAM-SHA1 support

Factor out GS2 tokanization into own class
Add authentication exception class

Fixes #71

1 files changed, 76 insertions, 0 deletions

diff --git a/src/main/java/eu/siacs/conversations/crypto/sasl/Tokenizer.java b/src/main/java/eu/siacs/conversations/crypto/sasl/Tokenizer.java
new file mode 100644
index 00000000..4797e6e8
--- /dev/null
+++ b/src/main/java/eu/siacs/conversations/crypto/sasl/Tokenizer.java
@@ -0,0 +1,76 @@
+package eu.siacs.conversations.crypto.sasl;
+
+import android.util.Base64;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Iterator;
+import java.util.List;
+import java.util.NoSuchElementException;
+
+/**
+ * A tokenizer for GS2 header strings
+ */
+public final class Tokenizer implements Iterator<String>, Iterable<String> {
+	private final List<String> parts;
+	private int index;
+
+	public Tokenizer(final byte[] challenge) {
+		final String challengeString = new String(challenge);
+		parts = new ArrayList<>(Arrays.asList(challengeString.split(",")));
+		index = 0;
+	}
+
+	/**
+	 * Returns true if there is at least one more element, false otherwise.
+	 *
+	 * @see #next
+	 */
+	@Override
+	public boolean hasNext() {
+		return parts.size() != index + 1;
+	}
+
+	/**
+	 * Returns the next object and advances the iterator.
+	 *
+	 * @return the next object.
+	 * @throws java.util.NoSuchElementException if there are no more elements.
+	 * @see #hasNext
+	 */
+	@Override
+	public String next() {
+		if (hasNext()) {
+			return parts.get(index++);
+		} else {
+			throw new NoSuchElementException("No such element. Size is: " + parts.size());
+		}
+	}
+
+	/**
+	 * Removes the last object returned by {@code next} from the collection.
+	 * This method can only be called once between each call to {@code next}.
+	 *
+	 * @throws UnsupportedOperationException if removing is not supported by the collection being
+	 *                                       iterated.
+	 * @throws IllegalStateException         if {@code next} has not been called, or {@code remove} has
+	 *                                       already been called after the last call to {@code next}.
+	 */
+	@Override
+	public void remove() {
+		if(index <= 0) {
+			throw new IllegalStateException("You can't delete an element before first next() method call");
+		}
+		parts.remove(--index);
+	}
+
+	/**
+	 * Returns an {@link java.util.Iterator} for the elements in this object.
+	 *
+	 * @return An {@code Iterator} instance.
+	 */
+	@Override
+	public Iterator<String> iterator() {
+		return parts.iterator();
+	}
+}