/*

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package com.sun.tools.classfile;

import java.io.IOException;

import java.util.LinkedHashSet;

import java.util.Set;

/**

 * See JVMS, sections 4.2, 4.6, 4.7.

 *

 *  <p><b>This is NOT part of any supported API.

 *  If you write code that depends on this, you do so at your own risk.

 *  This code and its internal interfaces are subject to change or

 *  deletion without notice.</b>

 */

public class AccessFlags {

    public static final int ACC_PUBLIC        = 0x0001; // class, inner, field, method

    public static final int ACC_PRIVATE       = 0x0002; //        inner, field, method

    public static final int ACC_PROTECTED     = 0x0004; //        inner, field, method

    public static final int ACC_STATIC        = 0x0008; //        inner, field, method

    public static final int ACC_FINAL         = 0x0010; // class, inner, field, method

    public static final int ACC_SUPER         = 0x0020; // class

    public static final int ACC_SYNCHRONIZED  = 0x0020; //                      method

    public static final int ACC_VOLATILE      = 0x0040; //               field

    public static final int ACC_BRIDGE        = 0x0040; //                      method

    public static final int ACC_TRANSIENT     = 0x0080; //               field

    public static final int ACC_VARARGS       = 0x0080; //                      method

    public static final int ACC_NATIVE        = 0x0100; //                      method

    public static final int ACC_INTERFACE     = 0x0200; // class, inner

    public static final int ACC_ABSTRACT      = 0x0400; // class, inner,        method

    public static final int ACC_STRICT        = 0x0800; //                      method

    public static final int ACC_SYNTHETIC     = 0x1000; // class, inner, field, method

    public static final int ACC_ANNOTATION    = 0x2000; // class, inner

    public static final int ACC_ENUM          = 0x4000; // class, inner, field

    public static enum Kind { Class, InnerClass, Field, Method}

    AccessFlags(ClassReader cr) throws IOException {

        this(cr.readUnsignedShort());

    }

    public AccessFlags(int flags) {

        this.flags = flags;

    }

    public AccessFlags ignore(int mask) {

        return new AccessFlags(flags & ~mask);

    }

    public boolean is(int mask) {

        return (flags & mask) != 0;

    }

    public int byteLength() {

        return 2;

    }

    private static final int[] classModifiers = {

        ACC_PUBLIC, ACC_FINAL, ACC_ABSTRACT

    };

    private static final int[] classFlags = {

        ACC_PUBLIC, ACC_FINAL, ACC_SUPER, ACC_INTERFACE, ACC_ABSTRACT,

    };

    public Set<String> getClassModifiers() {

        int f = ((flags & ACC_INTERFACE) != 0 ? flags & ~ACC_ABSTRACT : flags);

        return getModifiers(f, classModifiers, Kind.Class);

    }

    public Set<String> getClassFlags() {

        return getFlags(classFlags, Kind.Class);

    }

    private static final int[] innerClassModifiers = {

        ACC_PUBLIC, ACC_PRIVATE, ACC_PROTECTED, ACC_STATIC, ACC_FINAL,

        ACC_ABSTRACT

    };

    private static final int[] innerClassFlags = {

        ACC_PUBLIC, ACC_PRIVATE, ACC_PROTECTED, ACC_STATIC, ACC_FINAL, ACC_SUPER,

        ACC_INTERFACE, ACC_ABSTRACT, ACC_SYNTHETIC, ACC_ANNOTATION, ACC_ENUM

    };

    public Set<String> getInnerClassModifiers() {

        int f = ((flags & ACC_INTERFACE) != 0 ? flags & ~ACC_ABSTRACT : flags);

        return getModifiers(f, innerClassModifiers, Kind.InnerClass);

    }

    public Set<String> getInnerClassFlags() {

        return getFlags(innerClassFlags, Kind.InnerClass);

    }

    private static final int[] fieldModifiers = {

        ACC_PUBLIC, ACC_PRIVATE, ACC_PROTECTED, ACC_STATIC, ACC_FINAL,

        ACC_VOLATILE, ACC_TRANSIENT

    };

    private static final int[] fieldFlags = {

        ACC_PUBLIC, ACC_PRIVATE, ACC_PROTECTED, ACC_STATIC, ACC_FINAL,

        ACC_VOLATILE, ACC_TRANSIENT, ACC_SYNTHETIC, ACC_ENUM

    };

    public Set<String> getFieldModifiers() {

        return getModifiers(fieldModifiers, Kind.Field);

    }

    public Set<String> getFieldFlags() {

        return getFlags(fieldFlags, Kind.Field);

    }

    private static final int[] methodModifiers = {

        ACC_PUBLIC, ACC_PRIVATE, ACC_PROTECTED, ACC_STATIC, ACC_FINAL,

        ACC_SYNCHRONIZED, ACC_NATIVE, ACC_ABSTRACT, ACC_STRICT

    };

    private static final int[] methodFlags = {

        ACC_PUBLIC, ACC_PRIVATE, ACC_PROTECTED, ACC_STATIC, ACC_FINAL,

        ACC_SYNCHRONIZED, ACC_BRIDGE, ACC_VARARGS, ACC_NATIVE, ACC_ABSTRACT,

        ACC_STRICT, ACC_SYNTHETIC

    };

    public Set<String> getMethodModifiers() {

        return getModifiers(methodModifiers, Kind.Method);

    }

    public Set<String> getMethodFlags() {

        return getFlags(methodFlags, Kind.Method);

    }

    private Set<String> getModifiers(int[] modifierFlags, Kind t) {

        return getModifiers(flags, modifierFlags, t);

    }

    private static Set<String> getModifiers(int flags, int[] modifierFlags, Kind t) {

        Set<String> s = new LinkedHashSet<>();

        for (int m: modifierFlags) {

            if ((flags & m) != 0)

                s.add(flagToModifier(m, t));

        }

        return s;

    }

    private Set<String> getFlags(int[] expectedFlags, Kind t) {

        Set<String> s = new LinkedHashSet<>();

        int f = flags;

        for (int e: expectedFlags) {

            if ((f & e) != 0) {

                s.add(flagToName(e, t));

                f = f & ~e;

            }

        }

        while (f != 0) {

            int bit = Integer.highestOneBit(f);

            s.add("0x" + Integer.toHexString(bit));

            f = f & ~bit;

        }

        return s;

    }

    private static String flagToModifier(int flag, Kind t) {

        switch (flag) {

            case ACC_PUBLIC:

                return "public";

            case ACC_PRIVATE:

                return "private";

            case ACC_PROTECTED:

                return "protected";

            case ACC_STATIC:

                return "static";

            case ACC_FINAL:

                return "final";

            case ACC_SYNCHRONIZED:

                return "synchronized";

            case 0x80:

                return (t == Kind.Field ? "transient" : null);

            case ACC_VOLATILE:

                return "volatile";

            case ACC_NATIVE:

                return "native";

            case ACC_ABSTRACT:

                return "abstract";

            case ACC_STRICT:

                return "strictfp";

            case ACC_MANDATED:

                return "mandated";

            default:

                return null;

        }

    }

    private static String flagToName(int flag, Kind t) {

        switch (flag) {

        case ACC_PUBLIC:

            return "ACC_PUBLIC";

        case ACC_PRIVATE:

            return "ACC_PRIVATE";

        case ACC_PROTECTED:

            return "ACC_PROTECTED";

        case ACC_STATIC:

            return "ACC_STATIC";

        case ACC_FINAL:

            return "ACC_FINAL";

        case 0x20:

            return (t == Kind.Class ? "ACC_SUPER" : "ACC_SYNCHRONIZED");

        case 0x40:

            return (t == Kind.Field ? "ACC_VOLATILE" : "ACC_BRIDGE");

        case 0x80:

            return (t == Kind.Field ? "ACC_TRANSIENT" : "ACC_VARARGS");

        case ACC_NATIVE:

            return "ACC_NATIVE";

        case ACC_INTERFACE:

            return "ACC_INTERFACE";

        case ACC_ABSTRACT:

            return "ACC_ABSTRACT";

        case ACC_STRICT:

            return "ACC_STRICT";

        case ACC_SYNTHETIC:

            return "ACC_SYNTHETIC";

        case ACC_ANNOTATION:

            return "ACC_ANNOTATION";

        case ACC_ENUM:

            return "ACC_ENUM";

        default:

            return null;

        }

    }

    public final int flags;

}