feat: added some more utils to InsnSequence

src/main/java/ftbsc/lll/tools/InsnSequence.java

@@ -27,5 +27,73 @@ public class InsnSequence extends InsnList implements Opcodes {
 			throw new InstructionMismatchException("Nodes" + getFirst() + " and " + getLast() + " are not connected.");
 	}
 
-	//TODO replace
+	/**
+	 * Extends the existing get function from InsnList to allow for negative indexes.
+	 * @param index the index of the instruction that must be returned
+	 * @return the instruction whose index is given
+	 */
+	@Override
+	public AbstractInsnNode get(int index) {
+		if(index >= 0)
+			return super.get(index);
+		index = Math.abs(index);
+		if(index > size())
+			throw new IndexOutOfBoundsException();
+		return this.toArray()[size() - index];
+	}
+
+	/**
+	 * Replaces a node with another one. Mostly used internally.
+	 * @param oldNode node to replace
+	 * @param newNode new node
+	 */
+	public void replaceNode(AbstractInsnNode oldNode, AbstractInsnNode newNode) {
+		super.insert(oldNode, newNode);
+		super.remove(oldNode);
+	}
+
+	/**
+	 * Replaces n occurrences of said opcode with the given node.
+	 * @param opcode the opcode to replace
+	 * @param newNode the replacement node
+	 * @param amount how many occurrences to replace, set to 0 to replace all
+	 * @return true if anything was changed, false otherwise
+	 */
+	public boolean replace(int opcode, AbstractInsnNode newNode, int amount) {
+		return replace(opcode, newNode, amount, false);
+	}
+
+	/**
+	 * Replaces n occurrences of said opcode with the given node.
+	 * @param opcode the opcode to replace
+	 * @param newNode the replacement node
+	 * @param reverse whether the search should be done from the end
+	 * @param amount how many occurrences to replace, set to 0 to replace all
+	 * @return true if anything was changed, false otherwise
+	 */
+	public boolean replace(int opcode, AbstractInsnNode newNode, int amount, boolean reverse) {
+		boolean changed = false;
+		for(AbstractInsnNode cur = this.getFirst();
+		    cur != null && cur.getPrevious() != this.getLast() && cur.getNext() != this.getFirst();
+			cur = reverse ? cur.getPrevious() : cur.getNext()) {
+			if(cur.getOpcode() == opcode) {
+				this.replaceNode(cur, newNode);
+				changed = true;
+				amount--; // will go to negative if it was already 0, causing it to go on until for loop finishes
+				if(amount == 0)
+					return changed;
+			}
+		}
+		return changed;
+	}
+
+	/**
+	 * Cut a number of nodes from the list.
+	 * @param amount how many nodes to cut
+	 * @param reverse true if should cut from the end, false otherwise
+	 */
+	public void cut(int amount, boolean reverse) {
+		for(int i = 0; i < amount; i++)
+			this.remove(reverse ? getLast() : getFirst());
+	}
 }