/*

 * 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.DataOutputStream;

import java.io.IOException;

import java.io.OutputStream;

import java.util.Iterator;

/**

 * See JVMS, section 4.5.

 *

 *  <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 ConstantPool {

    public static class InvalidIndex extends ConstantPoolException {

        private static final long serialVersionUID = -4350294289300939730L;

        InvalidIndex(int index) {

            super(index);

        }

        @Override

        public String getMessage() {

            // i18n

            return "invalid index #" + index;

        }

    }

    public static class UnexpectedEntry extends ConstantPoolException {

        private static final long serialVersionUID = 6986335935377933211L;

        UnexpectedEntry(int index, int expected_tag, int found_tag) {

            super(index);

            this.expected_tag = expected_tag;

            this.found_tag = found_tag;

        }

        @Override

        public String getMessage() {

            // i18n?

            return "unexpected entry at #" + index + " -- expected tag " + expected_tag + ", found " + found_tag;

        }

        public final int expected_tag;

        public final int found_tag;

    }

    public static class InvalidEntry extends ConstantPoolException {

        private static final long serialVersionUID = 1000087545585204447L;

        InvalidEntry(int index, int tag) {

            super(index);

            this.tag = tag;

        }

        @Override

        public String getMessage() {

            // i18n?

            return "unexpected tag at #" + index + ": " + tag;

        }

        public final int tag;

    }

    public static class EntryNotFound extends ConstantPoolException {

        private static final long serialVersionUID = 2885537606468581850L;

        EntryNotFound(Object value) {

            super(-1);

            this.value = value;

        }

        @Override

        public String getMessage() {

            // i18n?

            return "value not found: " + value;

        }

        public final Object value;

    }

    public static final int CONSTANT_Utf8 = 1;

    public static final int CONSTANT_Integer = 3;

    public static final int CONSTANT_Float = 4;

    public static final int CONSTANT_Long = 5;

    public static final int CONSTANT_Double = 6;

    public static final int CONSTANT_Class = 7;

    public static final int CONSTANT_String = 8;

    public static final int CONSTANT_Fieldref = 9;

    public static final int CONSTANT_Methodref = 10;

    public static final int CONSTANT_InterfaceMethodref = 11;

    public static final int CONSTANT_NameAndType = 12;

    public static final int CONSTANT_MethodHandle = 15;

    public static final int CONSTANT_MethodType = 16;

    public static final int CONSTANT_InvokeDynamic = 18;

    public static enum RefKind {

        public final int tag;

            this.tag = tag;

        }

        static RefKind getRefkind(int tag) {

            switch(tag) {

                case 1:

                    return REF_getField;

                case 2:

                    return REF_getStatic;

                case 3:

                    return REF_putField;

                case 4:

                    return REF_putStatic;

                case 5:

                    return REF_invokeVirtual;

                case 6:

                    return REF_invokeStatic;

                case 7:

                    return REF_invokeSpecial;

                case 8:

                    return REF_newInvokeSpecial;

                case 9:

                    return REF_invokeInterface;

                default:

                    return null;

            }

        }

    }

    ConstantPool(ClassReader cr) throws IOException, InvalidEntry {

        int count = cr.readUnsignedShort();

        pool = new CPInfo[count];

        for (int i = 1; i < count; i++) {

            int tag = cr.readUnsignedByte();

            switch (tag) {

            case CONSTANT_Class:

                pool[i] = new CONSTANT_Class_info(this, cr);

                break;

            case CONSTANT_Double:

                pool[i] = new CONSTANT_Double_info(cr);

                i++;

                break;

            case CONSTANT_Fieldref:

                pool[i] = new CONSTANT_Fieldref_info(this, cr);

                break;

            case CONSTANT_Float:

                pool[i] = new CONSTANT_Float_info(cr);

                break;

            case CONSTANT_Integer:

                pool[i] = new CONSTANT_Integer_info(cr);

                break;

            case CONSTANT_InterfaceMethodref:

                pool[i] = new CONSTANT_InterfaceMethodref_info(this, cr);

                break;

            case CONSTANT_InvokeDynamic:

                pool[i] = new CONSTANT_InvokeDynamic_info(this, cr);

                break;

            case CONSTANT_Long:

                pool[i] = new CONSTANT_Long_info(cr);

                i++;

                break;

            case CONSTANT_MethodHandle:

                pool[i] = new CONSTANT_MethodHandle_info(this, cr);

                break;

            case CONSTANT_MethodType:

                pool[i] = new CONSTANT_MethodType_info(this, cr);

                break;

            case CONSTANT_Methodref:

                pool[i] = new CONSTANT_Methodref_info(this, cr);

                break;

            case CONSTANT_NameAndType:

                pool[i] = new CONSTANT_NameAndType_info(this, cr);

                break;

            case CONSTANT_String:

                pool[i] = new CONSTANT_String_info(this, cr);

                break;

            case CONSTANT_Utf8:

                pool[i] = new CONSTANT_Utf8_info(cr);

                break;

            default:

                throw new InvalidEntry(i, tag);

            }

        }

    }

    public ConstantPool(CPInfo[] pool) {

        this.pool = pool;

    }

    public int size() {

        return pool.length;

    }

    public int byteLength() {

        int length = 2;

        for (int i = 1; i < size(); ) {

            CPInfo cpInfo = pool[i];

            length += cpInfo.byteLength();

            i += cpInfo.size();

        }

        return length;

    }

    public CPInfo get(int index) throws InvalidIndex {

        if (index <= 0 || index >= pool.length)

            throw new InvalidIndex(index);

        CPInfo info = pool[index];

        if (info == null) {

            // this occurs for indices referencing the "second half" of an

            // 8 byte constant, such as CONSTANT_Double or CONSTANT_Long

            throw new InvalidIndex(index);

        }

        return pool[index];

    }

    private CPInfo get(int index, int expected_type) throws InvalidIndex, UnexpectedEntry {

        CPInfo info = get(index);

        if (info.getTag() != expected_type)

            throw new UnexpectedEntry(index, expected_type, info.getTag());

        return info;

    }

    public CONSTANT_Utf8_info getUTF8Info(int index) throws InvalidIndex, UnexpectedEntry {

        return ((CONSTANT_Utf8_info) get(index, CONSTANT_Utf8));

    }

    public CONSTANT_Class_info getClassInfo(int index) throws InvalidIndex, UnexpectedEntry {

        return ((CONSTANT_Class_info) get(index, CONSTANT_Class));

    }

    public CONSTANT_NameAndType_info getNameAndTypeInfo(int index) throws InvalidIndex, UnexpectedEntry {

        return ((CONSTANT_NameAndType_info) get(index, CONSTANT_NameAndType));

    }

    public String getUTF8Value(int index) throws InvalidIndex, UnexpectedEntry {

        return getUTF8Info(index).value;

    }

    public int getUTF8Index(String value) throws EntryNotFound {

        for (int i = 1; i < pool.length; i++) {

            CPInfo info = pool[i];

            if (info instanceof CONSTANT_Utf8_info &&

                    ((CONSTANT_Utf8_info) info).value.equals(value))

                return i;

        }

        throw new EntryNotFound(value);

    }

    public Iterable<CPInfo> entries() {

        return new Iterable<CPInfo>() {

            public Iterator<CPInfo> iterator() {

                return new Iterator<CPInfo>() {

                    public boolean hasNext() {

                        return next < pool.length;

                    }

                    public CPInfo next() {

                        current = pool[next];

                        switch (current.getTag()) {

                            case CONSTANT_Double:

                            case CONSTANT_Long:

                                next += 2;

                                break;

                            default:

                                next += 1;

                        }

                        return current;

                    }

                    public void remove() {

                        throw new UnsupportedOperationException();

                    }

                    private CPInfo current;

                    private int next = 1;

                };

            }

        };

    }

    private CPInfo[] pool;

    public interface Visitor<R,P> {

        R visitClass(CONSTANT_Class_info info, P p);

        R visitDouble(CONSTANT_Double_info info, P p);

        R visitFieldref(CONSTANT_Fieldref_info info, P p);

        R visitFloat(CONSTANT_Float_info info, P p);

        R visitInteger(CONSTANT_Integer_info info, P p);

        R visitInterfaceMethodref(CONSTANT_InterfaceMethodref_info info, P p);

        R visitInvokeDynamic(CONSTANT_InvokeDynamic_info info, P p);

        R visitLong(CONSTANT_Long_info info, P p);

        R visitNameAndType(CONSTANT_NameAndType_info info, P p);

        R visitMethodref(CONSTANT_Methodref_info info, P p);

        R visitMethodHandle(CONSTANT_MethodHandle_info info, P p);

        R visitMethodType(CONSTANT_MethodType_info info, P p);

        R visitString(CONSTANT_String_info info, P p);

        R visitUtf8(CONSTANT_Utf8_info info, P p);

    }

    public static abstract class CPInfo {

        CPInfo() {

            this.cp = null;

        }

        CPInfo(ConstantPool cp) {

            this.cp = cp;

        }

        public abstract int getTag();

        /** The number of slots in the constant pool used by this entry.

         * 2 for CONSTANT_Double and CONSTANT_Long; 1 for everything else. */

        public int size() {

            return 1;

        }

        public abstract int byteLength();

        public abstract <R,D> R accept(Visitor<R,D> visitor, D data);

        protected final ConstantPool cp;

    }

    public static abstract class CPRefInfo extends CPInfo {

        protected CPRefInfo(ConstantPool cp, ClassReader cr, int tag) throws IOException {

            super(cp);

            this.tag = tag;

            class_index = cr.readUnsignedShort();

            name_and_type_index = cr.readUnsignedShort();

        }

        protected CPRefInfo(ConstantPool cp, int tag, int class_index, int name_and_type_index) {

            super(cp);

            this.tag = tag;

            this.class_index = class_index;

            this.name_and_type_index = name_and_type_index;

        }

        public int getTag() {

            return tag;

        }

        public int byteLength() {

            return 5;

        }

        public CONSTANT_Class_info getClassInfo() throws ConstantPoolException {

            return cp.getClassInfo(class_index);

        }

        public String getClassName() throws ConstantPoolException {

            return cp.getClassInfo(class_index).getName();

        }

        public CONSTANT_NameAndType_info getNameAndTypeInfo() throws ConstantPoolException {

            return cp.getNameAndTypeInfo(name_and_type_index);

        }

        public final int tag;

        public final int class_index;

        public final int name_and_type_index;

    }

    public static class CONSTANT_Class_info extends CPInfo {

        CONSTANT_Class_info(ConstantPool cp, ClassReader cr) throws IOException {

            super(cp);

            name_index = cr.readUnsignedShort();

        }

        public CONSTANT_Class_info(ConstantPool cp, int name_index) {

            super(cp);

            this.name_index = name_index;

        }

        public int getTag() {

            return CONSTANT_Class;

        }

        public int  byteLength() {

            return 3;

        }

        /**

         * Get the raw value of the class referenced by this constant pool entry.

         * This will either be the name of the class, in internal form, or a

         * descriptor for an array class.

         * @return the raw value of the class

         */

        public String getName() throws ConstantPoolException {

            return cp.getUTF8Value(name_index);

        }

        /**

         * If this constant pool entry identifies either a class or interface type,

         * or a possibly multi-dimensional array of a class of interface type,

         * return the name of the class or interface in internal form. Otherwise,

         * (i.e. if this is a possibly multi-dimensional array of a primitive type),

         * return null.

         * @return the base class or interface name

         */

        public String getBaseName() throws ConstantPoolException {

            String name = getName();

            if (name.startsWith("[")) {

                int index = name.indexOf("[L");

                if (index == -1)

                    return null;

                return name.substring(index + 2, name.length() - 1);

            } else

                return name;

        }

        public int getDimensionCount() throws ConstantPoolException {

            String name = getName();

            int count = 0;

            while (name.charAt(count) == '[')

                count++;

            return count;

        }

        @Override

        public String toString() {

            return "CONSTANT_Class_info[name_index: " + name_index + "]";

        }

        public <R, D> R accept(Visitor<R, D> visitor, D data) {

            return visitor.visitClass(this, data);

        }

        public final int name_index;

    }

    public static class CONSTANT_Double_info extends CPInfo {

        CONSTANT_Double_info(ClassReader cr) throws IOException {

            value = cr.readDouble();

        }

        public CONSTANT_Double_info(double value) {

            this.value = value;

        }

        public int getTag() {

            return CONSTANT_Double;

        }

        public int  byteLength() {

            return 9;

        }

        @Override

        public int size() {

            return 2;

        }

        @Override

        public String toString() {

            return "CONSTANT_Double_info[value: " + value + "]";

        }

        public <R, D> R accept(Visitor<R, D> visitor, D data) {

            return visitor.visitDouble(this, data);

        }