    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 numberOfLocals = frameType - 251;
    073            typesOfLocals = new StackMapType[numberOfLocals];
    074            for (int i = 0; i < numberOfLocals; i++) {
    075                typesOfLocals[i] = new StackMapType(input, constantPool);
    076            }
    077        } else if (frameType == Const.FULL_FRAME) {
    078            byteCodeOffset = input.readShort();
    079            final int numberOfLocals = input.readShort();
    080            typesOfLocals = new StackMapType[numberOfLocals];
    081            for (int i = 0; i < numberOfLocals; i++) {
    082                typesOfLocals[i] = new StackMapType(input, constantPool);
    083            }
    084            final int numberOfStackItems = input.readShort();
    085            typesOfStackItems = new StackMapType[numberOfStackItems];
    086            for (int i = 0; i < numberOfStackItems; 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        if (numberOfLocals < 0) {
    114            throw new IllegalArgumentException("numberOfLocals < 0");
    115        }
    116        if (numberOfStackItems < 0) {
    117            throw new IllegalArgumentException("numberOfStackItems < 0");
    118        }
    119    }
    120
    121    /**
    122     * Create an instance
    123     *
    124     * @param tag the frameType to use
    125     * @param byteCodeOffset
    126     * @param typesOfLocals array of {@link StackMapType}s of locals
    127     * @param typesOfStackItems array ot {@link StackMapType}s of stack items
    128     * @param constantPool the constant pool
    129     */
    130    public StackMapEntry(final int tag, final int byteCodeOffset, final StackMapType[] typesOfLocals, final StackMapType[] typesOfStackItems,
    131        final ConstantPool constantPool) {
    132        this.frameType = tag;
    133        this.byteCodeOffset = byteCodeOffset;
    134        this.typesOfLocals = typesOfLocals != null ? typesOfLocals : EMPTY_STACK_MAP_TYPE_ARRAY;
    135        this.typesOfStackItems = typesOfStackItems != null ? typesOfStackItems : EMPTY_STACK_MAP_TYPE_ARRAY;
    136        this.constantPool = constantPool;
    137    }
    138
    139    /**
    140     * Called by objects that are traversing the nodes of the tree implicitly defined by the contents of a Java class.
    141     * I.e., the hierarchy of methods, fields, attributes, etc. spawns a tree of objects.
    142     *
    143     * @param v Visitor object
    144     */
    145    @Override
    146    public void accept(final Visitor v) {
    147        v.visitStackMapEntry(this);
    148    }
    149
    150    /**
    151     * @return deep copy of this object
    152     */
    153    public StackMapEntry copy() {
    154        StackMapEntry e;
    155        try {
    156            e = (StackMapEntry) clone();
    157        } catch (final CloneNotSupportedException ex) {
    158            throw new Error("Clone Not Supported");
    159        }
    160
    161        e.typesOfLocals = new StackMapType[typesOfLocals.length];
    162        Arrays.setAll(e.typesOfLocals, i -> typesOfLocals[i].copy());
    163        e.typesOfStackItems = new StackMapType[typesOfStackItems.length];
    164        Arrays.setAll(e.typesOfStackItems, i -> typesOfStackItems[i].copy());
    165        return e;
    166    }
    167
    168    /**
    169     * Dump stack map entry
    170     *
    171     * @param file Output file stream
    172     * @throws IOException if an I/O error occurs.
    173     */
    174    public void dump(final DataOutputStream file) throws IOException {
    175        file.write(frameType);
    176        if (frameType >= Const.SAME_LOCALS_1_STACK_ITEM_FRAME && frameType <= Const.SAME_LOCALS_1_STACK_ITEM_FRAME_MAX) {
    177            typesOfStackItems[0].dump(file);
    178        } else if (frameType == Const.SAME_LOCALS_1_STACK_ITEM_FRAME_EXTENDED) {
    179            file.writeShort(byteCodeOffset);
    180            typesOfStackItems[0].dump(file);
    181        } else if (frameType >= Const.CHOP_FRAME && frameType <= Const.CHOP_FRAME_MAX) {
    182            file.writeShort(byteCodeOffset);
    183        } else if (frameType == Const.SAME_FRAME_EXTENDED) {
    184            file.writeShort(byteCodeOffset);
    185        } else if (frameType >= Const.APPEND_FRAME && frameType <= Const.APPEND_FRAME_MAX) {
    186            file.writeShort(byteCodeOffset);
    187            for (final StackMapType type : typesOfLocals) {
    188                type.dump(file);
    189            }
    190        } else if (frameType == Const.FULL_FRAME) {
    191            file.writeShort(byteCodeOffset);
    192            file.writeShort(typesOfLocals.length);
    193            for (final StackMapType type : typesOfLocals) {
    194                type.dump(file);
    195            }
    196            file.writeShort(typesOfStackItems.length);
    197            for (final StackMapType type : typesOfStackItems) {
    198                type.dump(file);
    199            }
    200        } else if (!(frameType >= Const.SAME_FRAME && frameType <= Const.SAME_FRAME_MAX)) {
    201            /* Can't happen */
    202            throw new ClassFormatException("Invalid Stack map table tag: " + frameType);
    203        }
    204    }
    205
    206    public int getByteCodeOffset() {
    207        return byteCodeOffset;
    208    }
    209
    210    /**
    211     * @return Constant pool used by this object.
    212     */
    213    public ConstantPool getConstantPool() {
    214        return constantPool;
    215    }
    216
    217    public int getFrameType() {
    218        return frameType;
    219    }
    220
    221    /**
    222     * Calculate stack map entry size
    223     *
    224     */
    225    int getMapEntrySize() {
    226        if (frameType >= Const.SAME_FRAME && frameType <= Const.SAME_FRAME_MAX) {
    227            return 1;
    228        }
    229        if (frameType >= Const.SAME_LOCALS_1_STACK_ITEM_FRAME && frameType <= Const.SAME_LOCALS_1_STACK_ITEM_FRAME_MAX) {
    230            return 1 + (typesOfStackItems[0].hasIndex() ? 3 : 1);
    231        }
    232        if (frameType == Const.SAME_LOCALS_1_STACK_ITEM_FRAME_EXTENDED) {
    233            return 3 + (typesOfStackItems[0].hasIndex() ? 3 : 1);
    234        }
    235        if (frameType >= Const.CHOP_FRAME && frameType <= Const.CHOP_FRAME_MAX || frameType == Const.SAME_FRAME_EXTENDED) {
    236            return 3;
    237        }
    238        if (frameType >= Const.APPEND_FRAME && frameType <= Const.APPEND_FRAME_MAX) {
    239            int len = 3;
    240            for (final StackMapType typesOfLocal : typesOfLocals) {
    241                len += typesOfLocal.hasIndex() ? 3 : 1;
    242            }
    243            return len;
    244        }
    245        if (frameType != Const.FULL_FRAME) {
    246            throw new IllegalStateException("Invalid StackMap frameType: " + frameType);
    247        }
    248        int len = 7;
    249        for (final StackMapType typesOfLocal : typesOfLocals) {
    250            len += typesOfLocal.hasIndex() ? 3 : 1;
    251        }
    252        for (final StackMapType typesOfStackItem : typesOfStackItems) {
    253            len += typesOfStackItem.hasIndex() ? 3 : 1;
    254        }
    255        return len;
    256    }
    257
    258    public int getNumberOfLocals() {
    259        return typesOfLocals.length;
    260    }
    261
    262    public int getNumberOfStackItems() {
    263        return typesOfStackItems.length;
    264    }
    265
    266    public StackMapType[] getTypesOfLocals() {
    267        return typesOfLocals;
    268    }
    269
    270    public StackMapType[] getTypesOfStackItems() {
    271        return typesOfStackItems;
    272    }
    273
    274    private boolean invalidFrameType(final int f) {
    275        // @formatter:off
    276        return f != Const.SAME_LOCALS_1_STACK_ITEM_FRAME_EXTENDED
    277            && !(f >= Const.CHOP_FRAME && f <= Const.CHOP_FRAME_MAX)
    278            && f != Const.SAME_FRAME_EXTENDED
    279            && !(f >= Const.APPEND_FRAME && f <= Const.APPEND_FRAME_MAX)
    280            && f != Const.FULL_FRAME;
    281        // @formatter:on
    282    }
    283
    284    public void setByteCodeOffset(final int newOffset) {
    285        if (newOffset < 0 || newOffset > 32767) {
    286            throw new IllegalArgumentException("Invalid StackMap offset: " + newOffset);
    287        }
    288
    289        if (frameType >= Const.SAME_FRAME && frameType <= Const.SAME_FRAME_MAX) {
    290            if (newOffset > Const.SAME_FRAME_MAX) {
    291                frameType = Const.SAME_FRAME_EXTENDED;
    292            } else {
    293                frameType = newOffset;
    294            }
    295        } else if (frameType >= Const.SAME_LOCALS_1_STACK_ITEM_FRAME && frameType <= Const.SAME_LOCALS_1_STACK_ITEM_FRAME_MAX) {
    296            if (newOffset > Const.SAME_FRAME_MAX) {
    297                frameType = Const.SAME_LOCALS_1_STACK_ITEM_FRAME_EXTENDED;
    298            } else {
    299                frameType = Const.SAME_LOCALS_1_STACK_ITEM_FRAME + newOffset;
    300            }
    301        } else if (invalidFrameType(frameType)) {
    302            throw new IllegalStateException("Invalid StackMap frameType: " + frameType);
    303        }
    304        byteCodeOffset = newOffset;
    305    }
    306
    307    /**
    308     * @param constantPool Constant pool to be used for this object.
    309     */
    310    public void setConstantPool(final ConstantPool constantPool) {
    311        this.constantPool = constantPool;
    312    }
    313
    314    public void setFrameType(final int ft) {
    315        if (ft >= Const.SAME_FRAME && ft <= Const.SAME_FRAME_MAX) {
    316            byteCodeOffset = ft - Const.SAME_FRAME;
    317        } else if (ft >= Const.SAME_LOCALS_1_STACK_ITEM_FRAME && ft <= Const.SAME_LOCALS_1_STACK_ITEM_FRAME_MAX) {
    318            byteCodeOffset = ft - Const.SAME_LOCALS_1_STACK_ITEM_FRAME;
    319        } else if (invalidFrameType(ft)) {
    320            throw new IllegalArgumentException("Invalid StackMap frameType");
    321        }
    322        frameType = ft;
    323    }
    324
    325    /**
    326     *
    327     * @deprecated since 6.0
    328     */
    329    @java.lang.Deprecated
    330    public void setNumberOfLocals(final int n) { // TODO unused
    331    }
    332
    333    /**
    334     *
    335     * @deprecated since 6.0
    336     */
    337    @java.lang.Deprecated
    338    public void setNumberOfStackItems(final int n) { // TODO unused
    339    }
    340
    341    public void setTypesOfLocals(final StackMapType[] types) {
    342        typesOfLocals = types != null ? types : EMPTY_STACK_MAP_TYPE_ARRAY;
    343    }
    344
    345    public void setTypesOfStackItems(final StackMapType[] types) {
    346        typesOfStackItems = types != null ? types : EMPTY_STACK_MAP_TYPE_ARRAY;
    347    }
    348
    349    /**
    350     * @return String representation.
    351     */
    352    @Override
    353    public String toString() {
    354        final StringBuilder buf = new StringBuilder(64);
    355        buf.append("(");
    356        if (frameType >= Const.SAME_FRAME && frameType <= Const.SAME_FRAME_MAX) {
    357            buf.append("SAME");
    358        } else if (frameType >= Const.SAME_LOCALS_1_STACK_ITEM_FRAME && frameType <= Const.SAME_LOCALS_1_STACK_ITEM_FRAME_MAX) {
    359            buf.append("SAME_LOCALS_1_STACK");
    360        } else if (frameType == Const.SAME_LOCALS_1_STACK_ITEM_FRAME_EXTENDED) {
    361            buf.append("SAME_LOCALS_1_STACK_EXTENDED");
    362        } else if (frameType >= Const.CHOP_FRAME && frameType <= Const.CHOP_FRAME_MAX) {
    363            buf.append("CHOP ").append(String.valueOf(251 - frameType));
    364        } else if (frameType == Const.SAME_FRAME_EXTENDED) {
    365            buf.append("SAME_EXTENDED");
    366        } else if (frameType >= Const.APPEND_FRAME && frameType <= Const.APPEND_FRAME_MAX) {
    367            buf.append("APPEND ").append(String.valueOf(frameType - 251));
    368        } else if (frameType == Const.FULL_FRAME) {
    369            buf.append("FULL");
    370        } else {
    371            buf.append("UNKNOWN (").append(frameType).append(")");
    372        }
    373        buf.append(", offset delta=").append(byteCodeOffset);
    374        if (typesOfLocals.length > 0) {
    375            buf.append(", locals={");
    376            for (int i = 0; i < typesOfLocals.length; i++) {
    377                buf.append(typesOfLocals[i]);
    378                if (i < typesOfLocals.length - 1) {
    379                    buf.append(", ");
    380                }
    381            }
    382            buf.append("}");
    383        }
    384        if (typesOfStackItems.length > 0) {
    385            buf.append(", stack items={");
    386            for (int i = 0; i < typesOfStackItems.length; i++) {
    387                buf.append(typesOfStackItems[i]);
    388                if (i < typesOfStackItems.length - 1) {
    389                    buf.append(", ");
    390                }
    391            }
    392            buf.append("}");
    393        }
    394        buf.append(")");
    395        return buf.toString();
    396    }
    397
    398    /**
    399     * Update the distance (as an offset delta) from this StackMap entry to the next. Note that this might cause the
    400     * frame type to change. Note also that delta may be negative.
    401     *
    402     * @param delta offset delta
    403     */
    404    public void updateByteCodeOffset(final int delta) {
    405        setByteCodeOffset(byteCodeOffset + delta);
    406    }
    407}