dalvik/src/main/java/dalvik/bytecode/OpcodeInfo.java

/*
 * Copyright (C) 2010 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package dalvik.bytecode;

/**
 * Information about Dalvik opcodes.
 */
public final class OpcodeInfo {
    /**
     * The maximum possible value of a Dalvik opcode.
     *
     * <p><b>Note:</b>: This is constant in any given VM incarnation,
     * but it is subject to change over time, so it is not appropriate
     * to represent as a compile-time constant value.</p>
     */
    public static final int MAXIMUM_VALUE;

    /**
     * The maximum possible "packed value" of a Dalvik opcode. The
     * packed value of an opcode is a denser representation that is
     * only used when reporting usage statistics. The mapping between
     * packed opcode values and regular opcode values is
     * implementation-specific and may vary over time.
     *
     * <p><b>Note:</b>: This is constant in any given VM incarnation,
     * but it is subject to change over time, so it is not appropriate
     * to represent as a compile-time constant value.</p>
     *
     * @see dalvik.system.VMDebug.getInstructionCount()
     */
    public static final int MAXIMUM_PACKED_VALUE;

    static {
        /*
         * See note on the definition of MAXIMUM_VALUE, above, for
         * why it's not assigned directly on the declaration line.
         *
         * IMPORTANT NOTE: This assignment is generated automatically
         * by the opcode-gen tool. Any edits will get wiped out the
         * next time the tool is run.
         */
        // BEGIN(libcore-maximum-values); GENERATED AUTOMATICALLY BY opcode-gen
        MAXIMUM_VALUE = 65535;
        MAXIMUM_PACKED_VALUE = 511;
        // END(libcore-maximum-values)
    }

    /**
     * This class is not instantiable.
     */
    private OpcodeInfo() {
        // This space intentionally left blank.
    }

    /**
     * Returns whether the given packed opcode value represents a
     * method invocation operation. This includes most things that
     * look like method invocation at the source level, but it notably
     * excludes methods that are implemented directly in the VM as
     * well as ones the VM knows to have empty implementations.
     *
     * @hide Unclear if this is useful enough to publish as supported API.
     *
     * @param opcode one of the values defined in {@link Opcodes}
     */
    public static native boolean isInvoke(int packedOpcode);
}