/*
 * Copyright (c) 2007, 2015, Oracle and/or its affiliates. All rights reserved.
 * 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.
 
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.
/**
 * 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 final int ACC_MANDATED      = 0x8000; //                          method parameter
    public static final int ACC_MODULE        = 0x8000; // class

    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,
        ACC_SYNTHETIC, ACC_ANNOTATION, ACC_ENUM, ACC_MODULE
    };

    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";
        case 0x8000:
            return (t == Kind.Class ? "ACC_MODULE" : "ACC_MANDATED");
        default:
            return null;
        }
    }

    public final int flags;
}