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Tree module for CafeDude, containing a simplified intermediate model for classes

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package software.coley.cafedude.tree.insn;

import software.coley.cafedude.classfile.instruction.Opcodes;
import software.coley.cafedude.tree.visitor.reader.CodeReader;
import software.coley.cafedude.tree.visitor.writer.CodeWriter;

/**
 * Instruction which has an operand that is a local variable index, to either store or load from.
 * Instructions that use this is:
 * 
 *     {@link Opcodes#ILOAD}
 *     {@link Opcodes#LLOAD}
 *     {@link Opcodes#FLOAD}
 *     {@link Opcodes#DLOAD}
 *     {@link Opcodes#ALOAD}
 *     {@link Opcodes#ISTORE}
 *     {@link Opcodes#LSTORE}
 *     {@link Opcodes#FSTORE}
 *     {@link Opcodes#DSTORE}
 *     {@link Opcodes#ASTORE}
 * 
 * {@link CodeReader} will convert all XLOAD_N and XSTORE_N instructions to XLOAD and XSTORE with respective
 * operand values. 

 * {@link CodeWriter} will convert them to XLOAD_N and XSTORE_N instructions if possible.
 *
 * @author Justus Garbe
 * @see Opcodes#ILOAD_0
 * @see Opcodes#ISTORE_0
 */
public class VarInsn extends Insn {
	private int index;

	/**
	 * @param opcode
	 * 		Instruction opcode.
	 * @param index
	 * 		Local variable index.
	 */
	public VarInsn(int opcode, int index) {
		super(InsnKind.VAR, opcode);
		this.index = index;
	}

	/**
	 * @return Local variable index.
	 */
	public int getIndex() {
		return index;
	}

	/**
	 * @param index
	 * 		Local variable index.
	 */
	public void setIndex(int index) {
		this.index = index;
	}

	/**
	 * @return {@code true} when this insn can be mapped to a single op such as {@link Opcodes#ISTORE_0}.
	 */
	public boolean supportsSingleOpInsn() {
		// XLOAD_0 through XLOAD_3
		// XSTORE_0 through XSTORE_3
		return getIndex() <= 3;
	}

	@Override
	public int size() {
		// u1 opcode
		// u1 index
		return 2;
	}

	@Override
	public String toString() {
		return super.toString() + "(" + index + ")";
	}
}