    001/*
    002 * Licensed to the Apache Software Foundation (ASF) under one or more
    003 * contributor license agreements.  See the NOTICE file distributed with
    004 * this work for additional information regarding copyright ownership.
    005 * The ASF licenses this file to You under the Apache License, Version 2.0
    006 * (the "License"); you may not use this file except in compliance with
    007 * the License.  You may obtain a copy of the License at
    008 *
    009 *      http://www.apache.org/licenses/LICENSE-2.0
    010 *
    011 *  Unless required by applicable law or agreed to in writing, software
    012 *  distributed under the License is distributed on an "AS IS" BASIS,
    013 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    014 *  See the License for the specific language governing permissions and
    015 *  limitations under the License.
    016 */
    017
    018package org.apache.bcel.classfile;
    019
    020import java.io.DataInput;
    021import java.io.DataOutputStream;
    022import java.io.IOException;
    023import java.util.Arrays;
    024
    025import org.apache.bcel.Const;
    026
    027/**
    028 * This class represents a stack map entry recording the types of local variables and the of stack items at a given
    029 * byte code offset. See CLDC specification 5.3.1.2
    030 *
    031 * @see StackMap
    032 * @see StackMapType
    033 */
    034public final class StackMapEntry implements Node, Cloneable {
    035
    036    /**
    037     * Empty array.
    038     */
    039    private static final StackMapType[] EMPTY_STACK_MAP_TYPE_ARRAY = {};
    040
    041    private int frameType;
    042    private int byteCodeOffset;
    043    private StackMapType[] typesOfLocals;
    044    private StackMapType[] typesOfStackItems;
    045    private ConstantPool constantPool;
    046
    047    /**
    048     * Construct object from input stream.
    049     *
    050     * @param input Input stream
    051     * @throws IOException if an I/O error occurs.
    052     */
    053    StackMapEntry(final DataInput input, final ConstantPool constantPool) throws IOException {
    054        this(input.readByte() & 0xFF, -1, null, null, constantPool);
    055
    056        if (frameType >= Const.SAME_FRAME && frameType <= Const.SAME_FRAME_MAX) {
    057            byteCodeOffset = frameType - Const.SAME_FRAME;
    058        } else if (frameType >= Const.SAME_LOCALS_1_STACK_ITEM_FRAME && frameType <= Const.SAME_LOCALS_1_STACK_ITEM_FRAME_MAX) {
    059            byteCodeOffset = frameType - Const.SAME_LOCALS_1_STACK_ITEM_FRAME;
    060            typesOfStackItems = new StackMapType[1];
    061            typesOfStackItems[0] = new StackMapType(input, constantPool);
    062        } else if (frameType == Const.SAME_LOCALS_1_STACK_ITEM_FRAME_EXTENDED) {
    063            byteCodeOffset = input.readShort();
    064            typesOfStackItems = new StackMapType[1];
    065            typesOfStackItems[0] = new StackMapType(input, constantPool);
    066        } else if (frameType >= Const.CHOP_FRAME && frameType <= Const.CHOP_FRAME_MAX) {
    067            byteCodeOffset = input.readShort();
    068        } else if (frameType == Const.SAME_FRAME_EXTENDED) {
    069            byteCodeOffset = input.readShort();
    070        } else if (frameType >= Const.APPEND_FRAME && frameType <= Const.APPEND_FRAME_MAX) {
    071            byteCodeOffset = input.readShort();
    072            final int number_of_locals = frameType - 251;
    073            typesOfLocals = new StackMapType[number_of_locals];
    074            for (int i = 0; i < number_of_locals; i++) {
    075                typesOfLocals[i] = new StackMapType(input, constantPool);
    076            }
    077        } else if (frameType == Const.FULL_FRAME) {
    078            byteCodeOffset = input.readShort();
    079            final int number_of_locals = input.readShort();
    080            typesOfLocals = new StackMapType[number_of_locals];
    081            for (int i = 0; i < number_of_locals; i++) {
    082                typesOfLocals[i] = new StackMapType(input, constantPool);
    083            }
    084            final int number_of_stack_items = input.readShort();
    085            typesOfStackItems = new StackMapType[number_of_stack_items];
    086            for (int i = 0; i < number_of_stack_items; i++) {
    087                typesOfStackItems[i] = new StackMapType(input, constantPool);
    088            }
    089        } else {
    090            /* Can't happen */
    091            throw new ClassFormatException("Invalid frame type found while parsing stack map table: " + frameType);
    092        }
    093    }
    094
    095    /**
    096     * DO NOT USE
    097     *
    098     * @param byteCodeOffset
    099     * @param numberOfLocals NOT USED
    100     * @param typesOfLocals array of {@link StackMapType}s of locals
    101     * @param numberOfStackItems NOT USED
    102     * @param typesOfStackItems array ot {@link StackMapType}s of stack items
    103     * @param constantPool the constant pool
    104     * @deprecated Since 6.0, use {@link #StackMapEntry(int, int, StackMapType[], StackMapType[], ConstantPool)} instead
    105     */
    106    @java.lang.Deprecated
    107    public StackMapEntry(final int byteCodeOffset, final int numberOfLocals, final StackMapType[] typesOfLocals, final int numberOfStackItems,
    108        final StackMapType[] typesOfStackItems, final ConstantPool constantPool) {
    109        this.byteCodeOffset = byteCodeOffset;
    110        this.typesOfLocals = typesOfLocals != null ? typesOfLocals : EMPTY_STACK_MAP_TYPE_ARRAY;
    111        this.typesOfStackItems = typesOfStackItems != null ? typesOfStackItems : EMPTY_STACK_MAP_TYPE_ARRAY;
    112        this.constantPool = constantPool;
    113    }
    114
    115    /**
    116     * Create an instance
    117     *
    118     * @param tag the frameType to use
    119     * @param byteCodeOffset
    120     * @param typesOfLocals array of {@link StackMapType}s of locals
    121     * @param typesOfStackItems array ot {@link StackMapType}s of stack items
    122     * @param constantPool the constant pool
    123     */
    124    public StackMapEntry(final int tag, final int byteCodeOffset, final StackMapType[] typesOfLocals, final StackMapType[] typesOfStackItems,
    125        final ConstantPool constantPool) {
    126        this.frameType = tag;
    127        this.byteCodeOffset = byteCodeOffset;
    128        this.typesOfLocals = typesOfLocals != null ? typesOfLocals : EMPTY_STACK_MAP_TYPE_ARRAY;
    129        this.typesOfStackItems = typesOfStackItems != null ? typesOfStackItems : EMPTY_STACK_MAP_TYPE_ARRAY;
    130        this.constantPool = constantPool;
    131    }
    132
    133    /**
    134     * Called by objects that are traversing the nodes of the tree implicitly defined by the contents of a Java class.
    135     * I.e., the hierarchy of methods, fields, attributes, etc. spawns a tree of objects.
    136     *
    137     * @param v Visitor object
    138     */
    139    @Override
    140    public void accept(final Visitor v) {
    141        v.visitStackMapEntry(this);
    142    }
    143
    144    /**
    145     * @return deep copy of this object
    146     */
    147    public StackMapEntry copy() {
    148        StackMapEntry e;
    149        try {
    150            e = (StackMapEntry) clone();
    151        } catch (final CloneNotSupportedException ex) {
    152            throw new Error("Clone Not Supported");
    153        }
    154
    155        e.typesOfLocals = new StackMapType[typesOfLocals.length];
    156        Arrays.setAll(e.typesOfLocals, i -> typesOfLocals[i].copy());
    157        e.typesOfStackItems = new StackMapType[typesOfStackItems.length];
    158        Arrays.setAll(e.typesOfStackItems, i -> typesOfStackItems[i].copy());
    159        return e;
    160    }
    161
    162    /**
    163     * Dump stack map entry
    164     *
    165     * @param file Output file stream
    166     * @throws IOException if an I/O error occurs.
    167     */
    168    public void dump(final DataOutputStream file) throws IOException {
    169        file.write(frameType);
    170        if (frameType >= Const.SAME_FRAME && frameType <= Const.SAME_FRAME_MAX) {
    171            // nothing to be done
    172        } else if (frameType >= Const.SAME_LOCALS_1_STACK_ITEM_FRAME && frameType <= Const.SAME_LOCALS_1_STACK_ITEM_FRAME_MAX) {
    173            typesOfStackItems[0].dump(file);
    174        } else if (frameType == Const.SAME_LOCALS_1_STACK_ITEM_FRAME_EXTENDED) {
    175            file.writeShort(byteCodeOffset);
    176            typesOfStackItems[0].dump(file);
    177        } else if (frameType >= Const.CHOP_FRAME && frameType <= Const.CHOP_FRAME_MAX) {
    178            file.writeShort(byteCodeOffset);
    179        } else if (frameType == Const.SAME_FRAME_EXTENDED) {
    180            file.writeShort(byteCodeOffset);
    181        } else if (frameType >= Const.APPEND_FRAME && frameType <= Const.APPEND_FRAME_MAX) {
    182            file.writeShort(byteCodeOffset);
    183            for (final StackMapType type : typesOfLocals) {
    184                type.dump(file);
    185            }
    186        } else if (frameType == Const.FULL_FRAME) {
    187            file.writeShort(byteCodeOffset);
    188            file.writeShort(typesOfLocals.length);
    189            for (final StackMapType type : typesOfLocals) {
    190                type.dump(file);
    191            }
    192            file.writeShort(typesOfStackItems.length);
    193            for (final StackMapType type : typesOfStackItems) {
    194                type.dump(file);
    195            }
    196        } else {
    197            /* Can't happen */
    198            throw new ClassFormatException("Invalid Stack map table tag: " + frameType);
    199        }
    200    }
    201
    202    public int getByteCodeOffset() {
    203        return byteCodeOffset;
    204    }
    205
    206    /**
    207     * @return Constant pool used by this object.
    208     */
    209    public ConstantPool getConstantPool() {
    210        return constantPool;
    211    }
    212
    213    public int getFrameType() {
    214        return frameType;
    215    }
    216
    217    /**
    218     * Calculate stack map entry size
    219     *
    220     */
    221    int getMapEntrySize() {
    222        if (frameType >= Const.SAME_FRAME && frameType <= Const.SAME_FRAME_MAX) {
    223            return 1;
    224        }
    225        if (frameType >= Const.SAME_LOCALS_1_STACK_ITEM_FRAME && frameType <= Const.SAME_LOCALS_1_STACK_ITEM_FRAME_MAX) {
    226            return 1 + (typesOfStackItems[0].hasIndex() ? 3 : 1);
    227        }
    228        if (frameType == Const.SAME_LOCALS_1_STACK_ITEM_FRAME_EXTENDED) {
    229            return 3 + (typesOfStackItems[0].hasIndex() ? 3 : 1);
    230        }
    231        if (frameType >= Const.CHOP_FRAME && frameType <= Const.CHOP_FRAME_MAX || frameType == Const.SAME_FRAME_EXTENDED) {
    232            return 3;
    233        }
    234        if (frameType >= Const.APPEND_FRAME && frameType <= Const.APPEND_FRAME_MAX) {
    235            int len = 3;
    236            for (final StackMapType types_of_local : typesOfLocals) {
    237                len += types_of_local.hasIndex() ? 3 : 1;
    238            }
    239            return len;
    240        }
    241        if (frameType != Const.FULL_FRAME) {
    242            throw new IllegalStateException("Invalid StackMap frameType: " + frameType);
    243        }
    244        int len = 7;
    245        for (final StackMapType types_of_local : typesOfLocals) {
    246            len += types_of_local.hasIndex() ? 3 : 1;
    247        }
    248        for (final StackMapType types_of_stack_item : typesOfStackItems) {
    249            len += types_of_stack_item.hasIndex() ? 3 : 1;
    250        }
    251        return len;
    252    }
    253
    254    public int getNumberOfLocals() {
    255        return typesOfLocals.length;
    256    }
    257
    258    public int getNumberOfStackItems() {
    259        return typesOfStackItems.length;
    260    }
    261
    262    public StackMapType[] getTypesOfLocals() {
    263        return typesOfLocals;
    264    }
    265
    266    public StackMapType[] getTypesOfStackItems() {
    267        return typesOfStackItems;
    268    }
    269
    270    public void setByteCodeOffset(final int new_offset) {
    271        if (new_offset < 0 || new_offset > 32767) {
    272            throw new IllegalArgumentException("Invalid StackMap offset: " + new_offset);
    273        }
    274
    275        if (frameType >= Const.SAME_FRAME && frameType <= Const.SAME_FRAME_MAX) {
    276            if (new_offset > Const.SAME_FRAME_MAX) {
    277                frameType = Const.SAME_FRAME_EXTENDED;
    278            } else {
    279                frameType = new_offset;
    280            }
    281        } else if (frameType >= Const.SAME_LOCALS_1_STACK_ITEM_FRAME && frameType <= Const.SAME_LOCALS_1_STACK_ITEM_FRAME_MAX) {
    282            if (new_offset > Const.SAME_FRAME_MAX) {
    283                frameType = Const.SAME_LOCALS_1_STACK_ITEM_FRAME_EXTENDED;
    284            } else {
    285                frameType = Const.SAME_LOCALS_1_STACK_ITEM_FRAME + new_offset;
    286            }
    287        } else if (frameType == Const.SAME_LOCALS_1_STACK_ITEM_FRAME_EXTENDED) { // CHECKSTYLE IGNORE EmptyBlock
    288        } else if (frameType >= Const.CHOP_FRAME && frameType <= Const.CHOP_FRAME_MAX) { // CHECKSTYLE IGNORE EmptyBlock
    289        } else if (frameType == Const.SAME_FRAME_EXTENDED) { // CHECKSTYLE IGNORE EmptyBlock
    290        } else if (frameType >= Const.APPEND_FRAME && frameType <= Const.APPEND_FRAME_MAX) { // CHECKSTYLE IGNORE EmptyBlock
    291        } else if (frameType == Const.FULL_FRAME) { // CHECKSTYLE IGNORE EmptyBlock
    292        } else {
    293            throw new IllegalStateException("Invalid StackMap frameType: " + frameType);
    294        }
    295        byteCodeOffset = new_offset;
    296    }
    297
    298    /**
    299     * @param constantPool Constant pool to be used for this object.
    300     */
    301    public void setConstantPool(final ConstantPool constantPool) {
    302        this.constantPool = constantPool;
    303    }
    304
    305    public void setFrameType(final int f) {
    306        if (f >= Const.SAME_FRAME && f <= Const.SAME_FRAME_MAX) {
    307            byteCodeOffset = f - Const.SAME_FRAME;
    308        } else if (f >= Const.SAME_LOCALS_1_STACK_ITEM_FRAME && f <= Const.SAME_LOCALS_1_STACK_ITEM_FRAME_MAX) {
    309            byteCodeOffset = f - Const.SAME_LOCALS_1_STACK_ITEM_FRAME;
    310        } else if (f == Const.SAME_LOCALS_1_STACK_ITEM_FRAME_EXTENDED) { // CHECKSTYLE IGNORE EmptyBlock
    311        } else if (f >= Const.CHOP_FRAME && f <= Const.CHOP_FRAME_MAX) { // CHECKSTYLE IGNORE EmptyBlock
    312        } else if (f == Const.SAME_FRAME_EXTENDED) { // CHECKSTYLE IGNORE EmptyBlock
    313        } else if (f >= Const.APPEND_FRAME && f <= Const.APPEND_FRAME_MAX) { // CHECKSTYLE IGNORE EmptyBlock
    314        } else if (f == Const.FULL_FRAME) { // CHECKSTYLE IGNORE EmptyBlock
    315        } else {
    316            throw new IllegalArgumentException("Invalid StackMap frameType");
    317        }
    318        frameType = f;
    319    }
    320
    321    /**
    322     *
    323     * @deprecated since 6.0
    324     */
    325    @java.lang.Deprecated
    326    public void setNumberOfLocals(final int n) { // TODO unused
    327    }
    328
    329    /**
    330     *
    331     * @deprecated since 6.0
    332     */
    333    @java.lang.Deprecated
    334    public void setNumberOfStackItems(final int n) { // TODO unused
    335    }
    336
    337    public void setTypesOfLocals(final StackMapType[] types) {
    338        typesOfLocals = types != null ? types : EMPTY_STACK_MAP_TYPE_ARRAY;
    339    }
    340
    341    public void setTypesOfStackItems(final StackMapType[] types) {
    342        typesOfStackItems = types != null ? types : EMPTY_STACK_MAP_TYPE_ARRAY;
    343    }
    344
    345    /**
    346     * @return String representation.
    347     */
    348    @Override
    349    public String toString() {
    350        final StringBuilder buf = new StringBuilder(64);
    351        buf.append("(");
    352        if (frameType >= Const.SAME_FRAME && frameType <= Const.SAME_FRAME_MAX) {
    353            buf.append("SAME");
    354        } else if (frameType >= Const.SAME_LOCALS_1_STACK_ITEM_FRAME && frameType <= Const.SAME_LOCALS_1_STACK_ITEM_FRAME_MAX) {
    355            buf.append("SAME_LOCALS_1_STACK");
    356        } else if (frameType == Const.SAME_LOCALS_1_STACK_ITEM_FRAME_EXTENDED) {
    357            buf.append("SAME_LOCALS_1_STACK_EXTENDED");
    358        } else if (frameType >= Const.CHOP_FRAME && frameType <= Const.CHOP_FRAME_MAX) {
    359            buf.append("CHOP ").append(String.valueOf(251 - frameType));
    360        } else if (frameType == Const.SAME_FRAME_EXTENDED) {
    361            buf.append("SAME_EXTENDED");
    362        } else if (frameType >= Const.APPEND_FRAME && frameType <= Const.APPEND_FRAME_MAX) {
    363            buf.append("APPEND ").append(String.valueOf(frameType - 251));
    364        } else if (frameType == Const.FULL_FRAME) {
    365            buf.append("FULL");
    366        } else {
    367            buf.append("UNKNOWN (").append(frameType).append(")");
    368        }
    369        buf.append(", offset delta=").append(byteCodeOffset);
    370        if (typesOfLocals.length > 0) {
    371            buf.append(", locals={");
    372            for (int i = 0; i < typesOfLocals.length; i++) {
    373                buf.append(typesOfLocals[i]);
    374                if (i < typesOfLocals.length - 1) {
    375                    buf.append(", ");
    376                }
    377            }
    378            buf.append("}");
    379        }
    380        if (typesOfStackItems.length > 0) {
    381            buf.append(", stack items={");
    382            for (int i = 0; i < typesOfStackItems.length; i++) {
    383                buf.append(typesOfStackItems[i]);
    384                if (i < typesOfStackItems.length - 1) {
    385                    buf.append(", ");
    386                }
    387            }
    388            buf.append("}");
    389        }
    390        buf.append(")");
    391        return buf.toString();
    392    }
    393
    394    /**
    395     * Update the distance (as an offset delta) from this StackMap entry to the next. Note that this might cause the
    396     * frame type to change. Note also that delta may be negative.
    397     *
    398     * @param delta offset delta
    399     */
    400    public void updateByteCodeOffset(final int delta) {
    401        setByteCodeOffset(byteCodeOffset + delta);
    402    }
    403}