// ASM: a very small and fast Java bytecode manipulation framework
// Copyright (c) 2000-2011 INRIA, France Telecom
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//
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package net.hasor.utils.asm;
/**
 * A reference to a type appearing in a class, field or method declaration, or on an instruction.
 * Such a reference designates the part of the class where the referenced type is appearing (e.g. an
 * 'extends', 'implements' or 'throws' clause, a 'new' instruction, a 'catch' clause, a type cast, a
 * local variable declaration, etc).
 *
 * @author Eric Bruneton
 */
public class TypeReference {
    /**
     * The sort of type references that target a type parameter of a generic class. See {@link
     * #getSort}.
     */
    public static final int CLASS_TYPE_PARAMETER                 = 0x00;
    /**
     * The sort of type references that target a type parameter of a generic method. See {@link
     * #getSort}.
     */
    public static final int METHOD_TYPE_PARAMETER                = 0x01;
    /**
     * The sort of type references that target the super class of a class or one of the interfaces it
     * implements. See {@link #getSort}.
     */
    public static final int CLASS_EXTENDS                        = 0x10;
    /**
     * The sort of type references that target a bound of a type parameter of a generic class. See
     * {@link #getSort}.
     */
    public static final int CLASS_TYPE_PARAMETER_BOUND           = 0x11;
    /**
     * The sort of type references that target a bound of a type parameter of a generic method. See
     * {@link #getSort}.
     */
    public static final int METHOD_TYPE_PARAMETER_BOUND          = 0x12;
    /** The sort of type references that target the type of a field. See {@link #getSort}. */
    public static final int FIELD                                = 0x13;
    /** The sort of type references that target the return type of a method. See {@link #getSort}. */
    public static final int METHOD_RETURN                        = 0x14;
    /**
     * The sort of type references that target the receiver type of a method. See {@link #getSort}.
     */
    public static final int METHOD_RECEIVER                      = 0x15;
    /**
     * The sort of type references that target the type of a formal parameter of a method. See {@link
     * #getSort}.
     */
    public static final int METHOD_FORMAL_PARAMETER              = 0x16;
    /**
     * The sort of type references that target the type of an exception declared in the throws clause
     * of a method. See {@link #getSort}.
     */
    public static final int THROWS                               = 0x17;
    /**
     * The sort of type references that target the type of a local variable in a method. See {@link
     * #getSort}.
     */
    public static final int LOCAL_VARIABLE                       = 0x40;
    /**
     * The sort of type references that target the type of a resource variable in a method. See {@link
     * #getSort}.
     */
    public static final int RESOURCE_VARIABLE                    = 0x41;
    /**
     * The sort of type references that target the type of the exception of a 'catch' clause in a
     * method. See {@link #getSort}.
     */
    public static final int EXCEPTION_PARAMETER                  = 0x42;
    /**
     * The sort of type references that target the type declared in an 'instanceof' instruction. See
     * {@link #getSort}.
     */
    public static final int INSTANCEOF                           = 0x43;
    /**
     * The sort of type references that target the type of the object created by a 'new' instruction.
     * See {@link #getSort}.
     */
    public static final int NEW                                  = 0x44;
    /**
     * The sort of type references that target the receiver type of a constructor reference. See
     * {@link #getSort}.
     */
    public static final int CONSTRUCTOR_REFERENCE                = 0x45;
    /**
     * The sort of type references that target the receiver type of a method reference. See {@link
     * #getSort}.
     */
    public static final int METHOD_REFERENCE                     = 0x46;
    /**
     * The sort of type references that target the type declared in an explicit or implicit cast
     * instruction. See {@link #getSort}.
     */
    public static final int CAST                                 = 0x47;
    /**
     * The sort of type references that target a type parameter of a generic constructor in a
     * constructor call. See {@link #getSort}.
     */
    public static final int CONSTRUCTOR_INVOCATION_TYPE_ARGUMENT = 0x48;
    /**
     * The sort of type references that target a type parameter of a generic method in a method call.
     * See {@link #getSort}.
     */
    public static final int METHOD_INVOCATION_TYPE_ARGUMENT      = 0x49;
    /**
     * The sort of type references that target a type parameter of a generic constructor in a
     * constructor reference. See {@link #getSort}.
     */
    public static final int CONSTRUCTOR_REFERENCE_TYPE_ARGUMENT  = 0x4A;
    /**
     * The sort of type references that target a type parameter of a generic method in a method
     * reference. See {@link #getSort}.
     */
    public static final int METHOD_REFERENCE_TYPE_ARGUMENT       = 0x4B;
    /**
     * The target_type and target_info structures - as defined in the Java Virtual Machine
     * Specification (JVMS) - corresponding to this type reference. target_type uses one byte, and all
     * the target_info union fields use up to 3 bytes (except localvar_target, handled with the
     * specific method {@link MethodVisitor#visitLocalVariableAnnotation}). Thus, both structures can
     * be stored in an int.
     *
     * <p>This int field stores target_type (called the TypeReference 'sort' in the public API of this
     * class) in its most significant byte, followed by the target_info fields. Depending on
     * target_type, 1, 2 or even 3 least significant bytes of this field are unused. target_info
     * fields which reference bytecode offsets are set to 0 (these offsets are ignored in ClassReader,
     * and recomputed in MethodWriter).
     *
     * @see <a href="https://docs.oracle.com/javase/specs/jvms/se9/html/jvms-4.html#jvms-4.7.20">JVMS
     *     4.7.20</a>
     * @see <a
     *     href="https://docs.oracle.com/javase/specs/jvms/se9/html/jvms-4.html#jvms-4.7.20.1">JVMS
     *     4.7.20.1</a>
     */
    private final       int targetTypeAndInfo;

    /**
     * Constructs a new TypeReference.
     *
     * @param typeRef the int encoded value of the type reference, as received in a visit method
     *     related to type annotations, such as {@link ClassVisitor#visitTypeAnnotation}.
     */
    public TypeReference(final int typeRef) {
        this.targetTypeAndInfo = typeRef;
    }

    /**
     * Returns a type reference of the given sort.
     *
     * @param sort one of {@link #FIELD}, {@link #METHOD_RETURN}, {@link #METHOD_RECEIVER}, {@link
     *     #LOCAL_VARIABLE}, {@link #RESOURCE_VARIABLE}, {@link #INSTANCEOF}, {@link #NEW}, {@link
     *     #CONSTRUCTOR_REFERENCE}, or {@link #METHOD_REFERENCE}.
     * @return a type reference of the given sort.
     */
    public static TypeReference newTypeReference(final int sort) {
        return new TypeReference(sort << 24);
    }

    /**
     * Returns a reference to a type parameter of a generic class or method.
     *
     * @param sort one of {@link #CLASS_TYPE_PARAMETER} or {@link #METHOD_TYPE_PARAMETER}.
     * @param paramIndex the type parameter index.
     * @return a reference to the given generic class or method type parameter.
     */
    public static TypeReference newTypeParameterReference(final int sort, final int paramIndex) {
        return new TypeReference((sort << 24) | (paramIndex << 16));
    }

    /**
     * Returns a reference to a type parameter bound of a generic class or method.
     *
     * @param sort one of {@link #CLASS_TYPE_PARAMETER} or {@link #METHOD_TYPE_PARAMETER}.
     * @param paramIndex the type parameter index.
     * @param boundIndex the type bound index within the above type parameters.
     * @return a reference to the given generic class or method type parameter bound.
     */
    public static TypeReference newTypeParameterBoundReference(final int sort, final int paramIndex, final int boundIndex) {
        return new TypeReference((sort << 24) | (paramIndex << 16) | (boundIndex << 8));
    }

    /**
     * Returns a reference to the super class or to an interface of the 'implements' clause of a
     * class.
     *
     * @param itfIndex the index of an interface in the 'implements' clause of a class, or -1 to
     *     reference the super class of the class.
     * @return a reference to the given super type of a class.
     */
    public static TypeReference newSuperTypeReference(final int itfIndex) {
        return new TypeReference((CLASS_EXTENDS << 24) | ((itfIndex & 0xFFFF) << 8));
    }

    /**
     * Returns a reference to the type of a formal parameter of a method.
     *
     * @param paramIndex the formal parameter index.
     * @return a reference to the type of the given method formal parameter.
     */
    public static TypeReference newFormalParameterReference(final int paramIndex) {
        return new TypeReference((METHOD_FORMAL_PARAMETER << 24) | (paramIndex << 16));
    }

    /**
     * Returns a reference to the type of an exception, in a 'throws' clause of a method.
     *
     * @param exceptionIndex the index of an exception in a 'throws' clause of a method.
     * @return a reference to the type of the given exception.
     */
    public static TypeReference newExceptionReference(final int exceptionIndex) {
        return new TypeReference((THROWS << 24) | (exceptionIndex << 8));
    }

    /**
     * Returns a reference to the type of the exception declared in a 'catch' clause of a method.
     *
     * @param tryCatchBlockIndex the index of a try catch block (using the order in which they are
     *     visited with visitTryCatchBlock).
     * @return a reference to the type of the given exception.
     */
    public static TypeReference newTryCatchReference(final int tryCatchBlockIndex) {
        return new TypeReference((EXCEPTION_PARAMETER << 24) | (tryCatchBlockIndex << 8));
    }

    /**
     * Returns a reference to the type of a type argument in a constructor or method call or
     * reference.
     *
     * @param sort one of {@link #CAST}, {@link #CONSTRUCTOR_INVOCATION_TYPE_ARGUMENT}, {@link
     *     #METHOD_INVOCATION_TYPE_ARGUMENT}, {@link #CONSTRUCTOR_REFERENCE_TYPE_ARGUMENT}, or {@link
     *     #METHOD_REFERENCE_TYPE_ARGUMENT}.
     * @param argIndex the type argument index.
     * @return a reference to the type of the given type argument.
     */
    public static TypeReference newTypeArgumentReference(final int sort, final int argIndex) {
        return new TypeReference((sort << 24) | argIndex);
    }

    /**
     * Returns the sort of this type reference.
     *
     * @return one of {@link #CLASS_TYPE_PARAMETER}, {@link #METHOD_TYPE_PARAMETER}, {@link
     *     #CLASS_EXTENDS}, {@link #CLASS_TYPE_PARAMETER_BOUND}, {@link #METHOD_TYPE_PARAMETER_BOUND},
     *     {@link #FIELD}, {@link #METHOD_RETURN}, {@link #METHOD_RECEIVER}, {@link
     *     #METHOD_FORMAL_PARAMETER}, {@link #THROWS}, {@link #LOCAL_VARIABLE}, {@link
     *     #RESOURCE_VARIABLE}, {@link #EXCEPTION_PARAMETER}, {@link #INSTANCEOF}, {@link #NEW},
     *     {@link #CONSTRUCTOR_REFERENCE}, {@link #METHOD_REFERENCE}, {@link #CAST}, {@link
     *     #CONSTRUCTOR_INVOCATION_TYPE_ARGUMENT}, {@link #METHOD_INVOCATION_TYPE_ARGUMENT}, {@link
     *     #CONSTRUCTOR_REFERENCE_TYPE_ARGUMENT}, or {@link #METHOD_REFERENCE_TYPE_ARGUMENT}.
     */
    public int getSort() {
        return targetTypeAndInfo >>> 24;
    }

    /**
     * Returns the index of the type parameter referenced by this type reference. This method must
     * only be used for type references whose sort is {@link #CLASS_TYPE_PARAMETER}, {@link
     * #METHOD_TYPE_PARAMETER}, {@link #CLASS_TYPE_PARAMETER_BOUND} or {@link
     * #METHOD_TYPE_PARAMETER_BOUND}.
     *
     * @return a type parameter index.
     */
    public int getTypeParameterIndex() {
        return (targetTypeAndInfo & 0x00FF0000) >> 16;
    }

    /**
     * Returns the index of the type parameter bound, within the type parameter {@link
     * #getTypeParameterIndex}, referenced by this type reference. This method must only be used for
     * type references whose sort is {@link #CLASS_TYPE_PARAMETER_BOUND} or {@link
     * #METHOD_TYPE_PARAMETER_BOUND}.
     *
     * @return a type parameter bound index.
     */
    public int getTypeParameterBoundIndex() {
        return (targetTypeAndInfo & 0x0000FF00) >> 8;
    }

    /**
     * Returns the index of the "super type" of a class that is referenced by this type reference.
     * This method must only be used for type references whose sort is {@link #CLASS_EXTENDS}.
     *
     * @return the index of an interface in the 'implements' clause of a class, or -1 if this type
     *     reference references the type of the super class.
     */
    public int getSuperTypeIndex() {
        return (short) ((targetTypeAndInfo & 0x00FFFF00) >> 8);
    }

    /**
     * Returns the index of the formal parameter whose type is referenced by this type reference. This
     * method must only be used for type references whose sort is {@link #METHOD_FORMAL_PARAMETER}.
     *
     * @return a formal parameter index.
     */
    public int getFormalParameterIndex() {
        return (targetTypeAndInfo & 0x00FF0000) >> 16;
    }

    /**
     * Returns the index of the exception, in a 'throws' clause of a method, whose type is referenced
     * by this type reference. This method must only be used for type references whose sort is {@link
     * #THROWS}.
     *
     * @return the index of an exception in the 'throws' clause of a method.
     */
    public int getExceptionIndex() {
        return (targetTypeAndInfo & 0x00FFFF00) >> 8;
    }

    /**
     * Returns the index of the try catch block (using the order in which they are visited with
     * visitTryCatchBlock), whose 'catch' type is referenced by this type reference. This method must
     * only be used for type references whose sort is {@link #EXCEPTION_PARAMETER} .
     *
     * @return the index of an exception in the 'throws' clause of a method.
     */
    public int getTryCatchBlockIndex() {
        return (targetTypeAndInfo & 0x00FFFF00) >> 8;
    }

    /**
     * Returns the index of the type argument referenced by this type reference. This method must only
     * be used for type references whose sort is {@link #CAST}, {@link
     * #CONSTRUCTOR_INVOCATION_TYPE_ARGUMENT}, {@link #METHOD_INVOCATION_TYPE_ARGUMENT}, {@link
     * #CONSTRUCTOR_REFERENCE_TYPE_ARGUMENT}, or {@link #METHOD_REFERENCE_TYPE_ARGUMENT}.
     *
     * @return a type parameter index.
     */
    public int getTypeArgumentIndex() {
        return targetTypeAndInfo & 0xFF;
    }

    /**
     * Returns the int encoded value of this type reference, suitable for use in visit methods related
     * to type annotations, like visitTypeAnnotation.
     *
     * @return the int encoded value of this type reference.
     */
    public int getValue() {
        return targetTypeAndInfo;
    }

    /**
     * Puts the given target_type and target_info JVMS structures into the given ByteVector.
     *
     * @param targetTypeAndInfo a target_type and a target_info structures encoded as in {@link
     *     #targetTypeAndInfo}. LOCAL_VARIABLE and RESOURCE_VARIABLE target types are not supported.
     * @param output where the type reference must be put.
     */
    static void putTarget(final int targetTypeAndInfo, final ByteVector output) {
        switch (targetTypeAndInfo >>> 24) {
        case CLASS_TYPE_PARAMETER:
        case METHOD_TYPE_PARAMETER:
        case METHOD_FORMAL_PARAMETER:
            output.putShort(targetTypeAndInfo >>> 16);
            break;
        case FIELD:
        case METHOD_RETURN:
        case METHOD_RECEIVER:
            output.putByte(targetTypeAndInfo >>> 24);
            break;
        case CAST:
        case CONSTRUCTOR_INVOCATION_TYPE_ARGUMENT:
        case METHOD_INVOCATION_TYPE_ARGUMENT:
        case CONSTRUCTOR_REFERENCE_TYPE_ARGUMENT:
        case METHOD_REFERENCE_TYPE_ARGUMENT:
            output.putInt(targetTypeAndInfo);
            break;
        case CLASS_EXTENDS:
        case CLASS_TYPE_PARAMETER_BOUND:
        case METHOD_TYPE_PARAMETER_BOUND:
        case THROWS:
        case EXCEPTION_PARAMETER:
        case INSTANCEOF:
        case NEW:
        case CONSTRUCTOR_REFERENCE:
        case METHOD_REFERENCE:
            output.put12(targetTypeAndInfo >>> 24, (targetTypeAndInfo & 0xFFFF00) >> 8);
            break;
        default:
            throw new IllegalArgumentException();
        }
    }
}
