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 org.apache.bcel.Const;
024
025/**
026 * This class represents a stack map entry recording the types of
027 * local variables and the the of stack items at a given byte code offset.
028 * See CLDC specification 5.3.1.2
029 *
030 * @see     StackMap
031 * @see     StackMapType
032 */
033public final class StackMapEntry implements Node, Cloneable
034{
035
036    private int frame_type;
037    private int byte_code_offset;
038    private StackMapType[] types_of_locals;
039    private StackMapType[] types_of_stack_items;
040    private ConstantPool constant_pool;
041
042
043    /**
044     * Construct object from input stream.
045     *
046     * @param input Input stream
047     * @throws IOException
048     */
049    StackMapEntry(final DataInput input, final ConstantPool constantPool) throws IOException {
050        this(input.readByte() & 0xFF, -1, null, null, constantPool);
051
052        if (frame_type >= Const.SAME_FRAME && frame_type <= Const.SAME_FRAME_MAX) {
053            byte_code_offset = frame_type - Const.SAME_FRAME;
054        } else if (frame_type >= Const.SAME_LOCALS_1_STACK_ITEM_FRAME &&
055                   frame_type <= Const.SAME_LOCALS_1_STACK_ITEM_FRAME_MAX) {
056            byte_code_offset = frame_type - Const.SAME_LOCALS_1_STACK_ITEM_FRAME;
057            types_of_stack_items = new StackMapType[1];
058            types_of_stack_items[0] = new StackMapType(input, constantPool);
059        } else if (frame_type == Const.SAME_LOCALS_1_STACK_ITEM_FRAME_EXTENDED) {
060            byte_code_offset = input.readShort();
061            types_of_stack_items = new StackMapType[1];
062            types_of_stack_items[0] = new StackMapType(input, constantPool);
063        } else if (frame_type >= Const.CHOP_FRAME && frame_type <= Const.CHOP_FRAME_MAX) {
064            byte_code_offset = input.readShort();
065        } else if (frame_type == Const.SAME_FRAME_EXTENDED) {
066            byte_code_offset = input.readShort();
067        } else if (frame_type >= Const.APPEND_FRAME && frame_type <= Const.APPEND_FRAME_MAX) {
068            byte_code_offset = input.readShort();
069            final int number_of_locals = frame_type - 251;
070            types_of_locals = new StackMapType[number_of_locals];
071            for (int i = 0; i < number_of_locals; i++) {
072                types_of_locals[i] = new StackMapType(input, constantPool);
073            }
074        } else if (frame_type == Const.FULL_FRAME) {
075            byte_code_offset = input.readShort();
076            final int number_of_locals = input.readShort();
077            types_of_locals = new StackMapType[number_of_locals];
078            for (int i = 0; i < number_of_locals; i++) {
079                types_of_locals[i] = new StackMapType(input, constantPool);
080            }
081            final int number_of_stack_items = input.readShort();
082            types_of_stack_items = new StackMapType[number_of_stack_items];
083            for (int i = 0; i < number_of_stack_items; i++) {
084                types_of_stack_items[i] = new StackMapType(input, constantPool);
085            }
086        } else {
087            /* Can't happen */
088            throw new ClassFormatException ("Invalid frame type found while parsing stack map table: " + frame_type);
089        }
090    }
091
092    /**
093     * DO NOT USE
094     *
095     * @param byteCodeOffset
096     * @param numberOfLocals NOT USED
097     * @param typesOfLocals array of {@link StackMapType}s of locals
098     * @param numberOfStackItems NOT USED
099     * @param typesOfStackItems array ot {@link StackMapType}s of stack items
100     * @param constantPool the constant pool
101     * @deprecated Since 6.0, use {@link #StackMapEntry(int, int, StackMapType[], StackMapType[], ConstantPool)}
102     * instead
103     */
104    @java.lang.Deprecated
105    public StackMapEntry(final int byteCodeOffset, final int numberOfLocals,
106            final StackMapType[] typesOfLocals, final int numberOfStackItems,
107            final StackMapType[] typesOfStackItems, final ConstantPool constantPool) {
108        this.byte_code_offset = byteCodeOffset;
109        this.types_of_locals = typesOfLocals != null ? typesOfLocals : new StackMapType[0];
110        this.types_of_stack_items = typesOfStackItems != null ? typesOfStackItems : new StackMapType[0];
111        this.constant_pool = constantPool;
112    }
113
114    /**
115     * Create an instance
116     *
117     * @param tag the frame_type to use
118     * @param byteCodeOffset
119     * @param typesOfLocals array of {@link StackMapType}s of locals
120     * @param typesOfStackItems array ot {@link StackMapType}s of stack items
121     * @param constantPool the constant pool
122     */
123    public StackMapEntry(final int tag, final int byteCodeOffset,
124            final StackMapType[] typesOfLocals,
125            final StackMapType[] typesOfStackItems, final ConstantPool constantPool) {
126        this.frame_type = tag;
127        this.byte_code_offset = byteCodeOffset;
128        this.types_of_locals = typesOfLocals != null ? typesOfLocals : new StackMapType[0];
129        this.types_of_stack_items = typesOfStackItems != null ? typesOfStackItems : new StackMapType[0];
130        this.constant_pool = constantPool;
131    }
132
133
134    /**
135     * Dump stack map entry
136     *
137     * @param file Output file stream
138     * @throws IOException
139     */
140    public void dump( final DataOutputStream file ) throws IOException {
141        file.write(frame_type);
142        if (frame_type >= Const.SAME_FRAME && frame_type <= Const.SAME_FRAME_MAX) {
143            // nothing to be done
144        } else if (frame_type >= Const.SAME_LOCALS_1_STACK_ITEM_FRAME &&
145                   frame_type <= Const.SAME_LOCALS_1_STACK_ITEM_FRAME_MAX) {
146            types_of_stack_items[0].dump(file);
147        } else if (frame_type == Const.SAME_LOCALS_1_STACK_ITEM_FRAME_EXTENDED) {
148            file.writeShort(byte_code_offset);
149            types_of_stack_items[0].dump(file);
150        } else if (frame_type >= Const.CHOP_FRAME && frame_type <= Const.CHOP_FRAME_MAX) {
151            file.writeShort(byte_code_offset);
152        } else if (frame_type == Const.SAME_FRAME_EXTENDED) {
153            file.writeShort(byte_code_offset);
154        } else if (frame_type >= Const.APPEND_FRAME && frame_type <= Const.APPEND_FRAME_MAX) {
155            file.writeShort(byte_code_offset);
156            for (final StackMapType type : types_of_locals) {
157                type.dump(file);
158            }
159        } else if (frame_type == Const.FULL_FRAME) {
160            file.writeShort(byte_code_offset);
161            file.writeShort(types_of_locals.length);
162            for (final StackMapType type : types_of_locals) {
163                type.dump(file);
164            }
165            file.writeShort(types_of_stack_items.length);
166            for (final StackMapType type : types_of_stack_items) {
167                type.dump(file);
168            }
169        } else {
170            /* Can't happen */
171            throw new ClassFormatException ("Invalid Stack map table tag: " + frame_type);
172        }
173    }
174
175
176    /**
177     * @return String representation.
178     */
179    @Override
180    public String toString() {
181        final StringBuilder buf = new StringBuilder(64);
182        buf.append("(");
183        if (frame_type >= Const.SAME_FRAME && frame_type <= Const.SAME_FRAME_MAX) {
184            buf.append("SAME");
185        } else if (frame_type >= Const.SAME_LOCALS_1_STACK_ITEM_FRAME &&
186                  frame_type <= Const.SAME_LOCALS_1_STACK_ITEM_FRAME_MAX) {
187            buf.append("SAME_LOCALS_1_STACK");
188        } else if (frame_type == Const.SAME_LOCALS_1_STACK_ITEM_FRAME_EXTENDED) {
189            buf.append("SAME_LOCALS_1_STACK_EXTENDED");
190        } else if (frame_type >= Const.CHOP_FRAME && frame_type <= Const.CHOP_FRAME_MAX) {
191            buf.append("CHOP ").append(String.valueOf(251-frame_type));
192        } else if (frame_type == Const.SAME_FRAME_EXTENDED) {
193            buf.append("SAME_EXTENDED");
194        } else if (frame_type >= Const.APPEND_FRAME && frame_type <= Const.APPEND_FRAME_MAX) {
195            buf.append("APPEND ").append(String.valueOf(frame_type-251));
196        } else if (frame_type == Const.FULL_FRAME) {
197            buf.append("FULL");
198        } else {
199            buf.append("UNKNOWN (").append(frame_type).append(")");
200        }
201        buf.append(", offset delta=").append(byte_code_offset);
202        if (types_of_locals.length > 0) {
203            buf.append(", locals={");
204            for (int i = 0; i < types_of_locals.length; i++) {
205                buf.append(types_of_locals[i]);
206                if (i < types_of_locals.length - 1) {
207                    buf.append(", ");
208                }
209            }
210            buf.append("}");
211        }
212        if (types_of_stack_items.length > 0) {
213            buf.append(", stack items={");
214            for (int i = 0; i < types_of_stack_items.length; i++) {
215                buf.append(types_of_stack_items[i]);
216                if (i < types_of_stack_items.length - 1) {
217                    buf.append(", ");
218                }
219            }
220            buf.append("}");
221        }
222        buf.append(")");
223        return buf.toString();
224    }
225
226
227    /**
228     * Calculate stack map entry size
229     *
230     */
231    int getMapEntrySize() {
232        if (frame_type >= Const.SAME_FRAME && frame_type <= Const.SAME_FRAME_MAX) {
233            return 1;
234        } else if (frame_type >= Const.SAME_LOCALS_1_STACK_ITEM_FRAME &&
235                   frame_type <= Const.SAME_LOCALS_1_STACK_ITEM_FRAME_MAX) {
236            return 1 + (types_of_stack_items[0].hasIndex() ? 3 : 1);
237        } else if (frame_type == Const.SAME_LOCALS_1_STACK_ITEM_FRAME_EXTENDED) {
238            return 3 + (types_of_stack_items[0].hasIndex() ? 3 : 1);
239        } else if (frame_type >= Const.CHOP_FRAME && frame_type <= Const.CHOP_FRAME_MAX) {
240            return 3;
241        } else if (frame_type == Const.SAME_FRAME_EXTENDED) {
242            return 3;
243        } else if (frame_type >= Const.APPEND_FRAME && frame_type <= Const.APPEND_FRAME_MAX) {
244            int len = 3;
245            for (final StackMapType types_of_local : types_of_locals) {
246                len += types_of_local.hasIndex() ? 3 : 1;
247            }
248            return len;
249        } else if (frame_type == Const.FULL_FRAME) {
250            int len = 7;
251            for (final StackMapType types_of_local : types_of_locals) {
252                len += types_of_local.hasIndex() ? 3 : 1;
253            }
254            for (final StackMapType types_of_stack_item : types_of_stack_items) {
255                len += types_of_stack_item.hasIndex() ? 3 : 1;
256            }
257            return len;
258        } else {
259            throw new RuntimeException("Invalid StackMap frame_type: " + frame_type);
260        }
261    }
262
263
264    public void setFrameType( final int f ) {
265        if (f >= Const.SAME_FRAME && f <= Const.SAME_FRAME_MAX) {
266            byte_code_offset = f - Const.SAME_FRAME;
267        } else if (f >= Const.SAME_LOCALS_1_STACK_ITEM_FRAME &&
268                   f <= Const.SAME_LOCALS_1_STACK_ITEM_FRAME_MAX) {
269            byte_code_offset = f - Const.SAME_LOCALS_1_STACK_ITEM_FRAME;
270        } else if (f == Const.SAME_LOCALS_1_STACK_ITEM_FRAME_EXTENDED) { // CHECKSTYLE IGNORE EmptyBlock
271        } else if (f >= Const.CHOP_FRAME && f <= Const.CHOP_FRAME_MAX) { // CHECKSTYLE IGNORE EmptyBlock
272        } else if (f == Const.SAME_FRAME_EXTENDED) { // CHECKSTYLE IGNORE EmptyBlock
273        } else if (f >= Const.APPEND_FRAME && f <= Const.APPEND_FRAME_MAX) { // CHECKSTYLE IGNORE EmptyBlock
274        } else if (f == Const.FULL_FRAME) { // CHECKSTYLE IGNORE EmptyBlock
275        } else {
276            throw new RuntimeException("Invalid StackMap frame_type");
277        }
278        frame_type = f;
279    }
280
281
282    public int getFrameType() {
283        return frame_type;
284    }
285
286
287    public void setByteCodeOffset( final int new_offset ) {
288        if (new_offset < 0 || new_offset > 32767) {
289            throw new RuntimeException("Invalid StackMap offset: " + new_offset);
290        }
291
292        if (frame_type >= Const.SAME_FRAME &&
293            frame_type <= Const.SAME_FRAME_MAX) {
294            if (new_offset > Const.SAME_FRAME_MAX) {
295                frame_type = Const.SAME_FRAME_EXTENDED;
296            } else {
297                frame_type = new_offset;
298            }
299        } else if (frame_type >= Const.SAME_LOCALS_1_STACK_ITEM_FRAME &&
300                   frame_type <= Const.SAME_LOCALS_1_STACK_ITEM_FRAME_MAX) {
301            if (new_offset > Const.SAME_FRAME_MAX) {
302                frame_type = Const.SAME_LOCALS_1_STACK_ITEM_FRAME_EXTENDED;
303            } else {
304                frame_type = Const.SAME_LOCALS_1_STACK_ITEM_FRAME + new_offset;
305            }
306        } else if (frame_type == Const.SAME_LOCALS_1_STACK_ITEM_FRAME_EXTENDED) { // CHECKSTYLE IGNORE EmptyBlock
307        } else if (frame_type >= Const.CHOP_FRAME &&
308                   frame_type <= Const.CHOP_FRAME_MAX) { // CHECKSTYLE IGNORE EmptyBlock
309        } else if (frame_type == Const.SAME_FRAME_EXTENDED) { // CHECKSTYLE IGNORE EmptyBlock
310        } else if (frame_type >= Const.APPEND_FRAME &&
311                   frame_type <= Const.APPEND_FRAME_MAX) { // CHECKSTYLE IGNORE EmptyBlock
312        } else if (frame_type == Const.FULL_FRAME) { // CHECKSTYLE IGNORE EmptyBlock
313        } else {
314            throw new RuntimeException("Invalid StackMap frame_type: " + frame_type);
315        }
316        byte_code_offset = new_offset;
317    }
318
319
320    /**
321     * Update the distance (as an offset delta) from this StackMap
322     * entry to the next.  Note that this might cause the the
323     * frame type to change.  Note also that delta may be negative.
324     *
325     * @param delta offset delta
326     */
327    public void updateByteCodeOffset(final int delta) {
328        setByteCodeOffset(byte_code_offset + delta);
329    }
330
331
332    public int getByteCodeOffset() {
333        return byte_code_offset;
334    }
335
336
337    /**
338     *
339     * @deprecated since 6.0
340     */
341    @java.lang.Deprecated
342    public void setNumberOfLocals( final int n ) { // TODO unused
343    }
344
345
346    public int getNumberOfLocals() {
347        return types_of_locals.length;
348    }
349
350
351    public void setTypesOfLocals( final StackMapType[] types ) {
352        types_of_locals = types != null ? types : new StackMapType[0];
353    }
354
355
356    public StackMapType[] getTypesOfLocals() {
357        return types_of_locals;
358    }
359
360
361    /**
362     *
363     * @deprecated since 6.0
364     */
365    @java.lang.Deprecated
366    public void setNumberOfStackItems( final int n ) { // TODO unused
367    }
368
369
370    public int getNumberOfStackItems() {
371        return types_of_stack_items.length;
372    }
373
374
375    public void setTypesOfStackItems( final StackMapType[] types ) {
376        types_of_stack_items = types != null ? types : new StackMapType[0];
377    }
378
379
380    public StackMapType[] getTypesOfStackItems() {
381        return types_of_stack_items;
382    }
383
384
385    /**
386     * @return deep copy of this object
387     */
388    public StackMapEntry copy() {
389        StackMapEntry e;
390        try {
391            e = (StackMapEntry) clone();
392        } catch (final CloneNotSupportedException ex) {
393            throw new Error("Clone Not Supported");
394        }
395
396        e.types_of_locals = new StackMapType[types_of_locals.length];
397        for (int i = 0; i < types_of_locals.length; i++) {
398            e.types_of_locals[i] = types_of_locals[i].copy();
399        }
400        e.types_of_stack_items = new StackMapType[types_of_stack_items.length];
401        for (int i = 0; i < types_of_stack_items.length; i++) {
402            e.types_of_stack_items[i] = types_of_stack_items[i].copy();
403        }
404        return e;
405    }
406
407
408    /**
409     * Called by objects that are traversing the nodes of the tree implicitely
410     * defined by the contents of a Java class. I.e., the hierarchy of methods,
411     * fields, attributes, etc. spawns a tree of objects.
412     *
413     * @param v Visitor object
414     */
415    @Override
416    public void accept( final Visitor v ) {
417        v.visitStackMapEntry(this);
418    }
419
420
421    /**
422     * @return Constant pool used by this object.
423     */
424    public ConstantPool getConstantPool() {
425        return constant_pool;
426    }
427
428
429    /**
430     * @param constant_pool Constant pool to be used for this object.
431     */
432    public void setConstantPool( final ConstantPool constant_pool ) {
433        this.constant_pool = constant_pool;
434    }
435}