1 files changed, 126 insertions, 0 deletions
diff --git a/base/src/main/java/bjc/utils/esodata/Tape.java b/base/src/main/java/bjc/utils/esodata/Tape.java
new file mode 100644
index 0000000..b6a2c01
--- /dev/null
+++ b/base/src/main/java/bjc/utils/esodata/Tape.java
@@ -0,0 +1,126 @@
+package bjc.utils.esodata;
+
+/**
+ * Interface for something that acts like a tape.
+ *
+ * A tape is essentially a 1D array with a cursor attached to it, and you can
+ * only affect elements at that cursor. The size of the array is theoretically
+ * unbounded to the right, but in practice bounded by available memory.
+ *
+ * @param <T>
+ *                The element type of the tape.
+ *
+ * @author bjculkin
+ */
+public interface Tape<T> {
+	/**
+	 * Get the item the tape is currently on.
+	 *
+	 * @return The item the tape is on.
+	 */
+	T item();
+
+	/**
+	 * Set the item the tape is currently on.
+	 *
+	 * @param itm
+	 *                The new value for the tape item.
+	 */
+	void item(T itm);
+
+	/**
+	 * Get the current number of elements in the tape.
+	 *
+	 * @return The current number of elements in the tape.
+	 */
+	int size();
+
+	/**
+	 * Get the position of the current item.
+	 *
+	 * @return The position of the current item.
+	 */
+	int position();
+
+	/**
+	 * Insert an element before the current item.
+	 *
+	 * @param itm
+	 *                The item to add.
+	 */
+	void insertBefore(T itm);
+
+	/**
+	 * Insert an element after the current item.
+	 *
+	 * @param itm
+	 *                The item to insert.
+	 */
+	void insertAfter(T itm);
+
+	/**
+	 * Remove the current element.
+	 *
+	 * Also moves the cursor back one step if possible to maintain relative
+	 * position.
+	 *
+	 * @return The removed item.
+	 */
+	T remove();
+
+	/**
+	 * Move the cursor to the left-most position.
+	 */
+	void first();
+
+	/**
+	 * Move the cursor the right-most position.
+	 */
+	void last();
+
+	/**
+	 * Move the cursor one space left.
+	 *
+	 * The cursor can't go past zero.
+	 *
+	 * @return True if the cursor was moved left.
+	 */
+	boolean left();
+
+	/**
+	 * Move the cursor the specified amount left.
+	 *
+	 * The cursor can't go past zero. Attempts to move the cursor by amounts
+	 * that would exceed zero don't move the cursor at all.
+	 *
+	 * @param amt
+	 *                The amount to attempt to move the cursor left.
+	 *
+	 * @return True if the cursor was moved left.
+	 */
+	boolean left(int amt);
+
+	/**
+	 * Move the cursor one space right.
+	 *
+	 * @return Whether the cursor was moved right.
+	 */
+	boolean right();
+
+	/**
+	 * Move the cursor the specified amount right.
+	 *
+	 * @param amt
+	 *                The amount to move the cursor right by.
+	 *
+	 * @return Whether the cursor was moved right.
+	 */
+	boolean right(int amt);
+
+	/**
+	 * Is this tape double sided?
+	 *
+	 * @return Whether or not this tape is double-sided.
+	 */
+	boolean isDoubleSided();
+}