001/*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *   https://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing,
013 * software distributed under the License is distributed on an
014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 * KIND, either express or implied.  See the License for the
016 * specific language governing permissions and limitations
017 * under the License.
018 */
019package org.apache.commons.compress.harmony.unpack200.bytecode.forms;
020
021import java.util.Arrays;
022import java.util.HashMap;
023import java.util.Map;
024
025import org.apache.commons.compress.harmony.pack200.Pack200Exception;
026import org.apache.commons.compress.harmony.unpack200.bytecode.ByteCode;
027import org.apache.commons.compress.harmony.unpack200.bytecode.CodeAttribute;
028import org.apache.commons.compress.harmony.unpack200.bytecode.OperandManager;
029
030/**
031 * Abstract byte code form.
032 */
033public abstract class ByteCodeForm {
034
035    protected static final boolean WIDENED = true;
036
037    protected static final ByteCodeForm[] byteCodeArray = new ByteCodeForm[256];
038    protected static final Map<String, ByteCodeForm> byteCodesByName = new HashMap<>(256);
039    static {
040        byteCodeArray[0] = new NoArgumentForm(0, "nop");
041        byteCodeArray[1] = new NoArgumentForm(1, "aconst_null");
042        byteCodeArray[2] = new NoArgumentForm(2, "iconst_m1");
043        byteCodeArray[3] = new NoArgumentForm(3, "iconst_0");
044        byteCodeArray[4] = new NoArgumentForm(4, "iconst_1");
045        byteCodeArray[5] = new NoArgumentForm(5, "iconst_2");
046        byteCodeArray[6] = new NoArgumentForm(6, "iconst_3");
047        byteCodeArray[7] = new NoArgumentForm(7, "iconst_4");
048        byteCodeArray[8] = new NoArgumentForm(8, "iconst_5");
049        byteCodeArray[9] = new NoArgumentForm(9, "lconst_0");
050        byteCodeArray[10] = new NoArgumentForm(10, "lconst_1");
051        byteCodeArray[11] = new NoArgumentForm(11, "fconst_0");
052        byteCodeArray[12] = new NoArgumentForm(12, "fconst_1");
053        byteCodeArray[13] = new NoArgumentForm(13, "fconst_2");
054        byteCodeArray[14] = new NoArgumentForm(14, "dconst_0");
055        byteCodeArray[15] = new NoArgumentForm(15, "dconst_1");
056        byteCodeArray[16] = new ByteForm(16, "bipush", new int[] { 16, -1 });
057        byteCodeArray[17] = new ShortForm(17, "sipush", new int[] { 17, -1, -1 });
058        byteCodeArray[18] = new StringRefForm(18, "ldc", new int[] { 18, -1 });
059        byteCodeArray[19] = new StringRefForm(19, "ldc_w", new int[] { 19, -1, -1 }, WIDENED);
060        byteCodeArray[20] = new LongForm(20, "ldc2_w", new int[] { 20, -1, -1 });
061        byteCodeArray[21] = new LocalForm(21, "iload", new int[] { 21, -1 });
062        byteCodeArray[22] = new LocalForm(22, "lload", new int[] { 22, -1 });
063        byteCodeArray[23] = new LocalForm(23, "fload", new int[] { 23, -1 });
064        byteCodeArray[24] = new LocalForm(24, "dload", new int[] { 24, -1 });
065        byteCodeArray[25] = new LocalForm(25, "aload", new int[] { 25, -1 });
066        byteCodeArray[26] = new NoArgumentForm(26, "iload_0");
067        byteCodeArray[27] = new NoArgumentForm(27, "iload_1");
068        byteCodeArray[28] = new NoArgumentForm(28, "iload_2");
069        byteCodeArray[29] = new NoArgumentForm(29, "iload_3");
070        byteCodeArray[30] = new NoArgumentForm(30, "lload_0");
071        byteCodeArray[31] = new NoArgumentForm(31, "lload_1");
072        byteCodeArray[32] = new NoArgumentForm(32, "lload_2");
073        byteCodeArray[33] = new NoArgumentForm(33, "lload_3");
074        byteCodeArray[34] = new NoArgumentForm(34, "fload_0");
075        byteCodeArray[35] = new NoArgumentForm(35, "fload_1");
076        byteCodeArray[36] = new NoArgumentForm(36, "fload_2");
077        byteCodeArray[37] = new NoArgumentForm(37, "fload_3");
078        byteCodeArray[38] = new NoArgumentForm(38, "dload_0");
079        byteCodeArray[39] = new NoArgumentForm(39, "dload_1");
080        byteCodeArray[40] = new NoArgumentForm(40, "dload_2");
081        byteCodeArray[41] = new NoArgumentForm(41, "dload_3");
082        byteCodeArray[42] = new NoArgumentForm(42, "aload_0");
083        byteCodeArray[43] = new NoArgumentForm(43, "aload_1");
084        byteCodeArray[44] = new NoArgumentForm(44, "aload_2");
085        byteCodeArray[45] = new NoArgumentForm(45, "aload_3");
086        byteCodeArray[46] = new NoArgumentForm(46, "iaload");
087        byteCodeArray[47] = new NoArgumentForm(47, "laload");
088        byteCodeArray[48] = new NoArgumentForm(48, "faload");
089        byteCodeArray[49] = new NoArgumentForm(49, "daload");
090        byteCodeArray[50] = new NoArgumentForm(50, "aaload");
091        byteCodeArray[51] = new NoArgumentForm(51, "baload");
092        byteCodeArray[52] = new NoArgumentForm(52, "caload");
093        byteCodeArray[53] = new NoArgumentForm(53, "saload");
094        byteCodeArray[54] = new LocalForm(54, "istore", new int[] { 54, -1 });
095        byteCodeArray[55] = new LocalForm(55, "lstore", new int[] { 55, -1 });
096        byteCodeArray[56] = new LocalForm(56, "fstore", new int[] { 56, -1 });
097        byteCodeArray[57] = new LocalForm(57, "dstore", new int[] { 57, -1 });
098        byteCodeArray[58] = new LocalForm(58, "astore", new int[] { 58, -1 });
099        byteCodeArray[59] = new NoArgumentForm(59, "istore_0");
100        byteCodeArray[60] = new NoArgumentForm(60, "istore_1");
101        byteCodeArray[61] = new NoArgumentForm(61, "istore_2");
102        byteCodeArray[62] = new NoArgumentForm(62, "istore_3");
103        byteCodeArray[63] = new NoArgumentForm(63, "lstore_0");
104        byteCodeArray[64] = new NoArgumentForm(64, "lstore_1");
105        byteCodeArray[65] = new NoArgumentForm(65, "lstore_2");
106        byteCodeArray[66] = new NoArgumentForm(66, "lstore_3");
107        byteCodeArray[67] = new NoArgumentForm(67, "fstore_0");
108        byteCodeArray[68] = new NoArgumentForm(68, "fstore_1");
109        byteCodeArray[69] = new NoArgumentForm(69, "fstore_2");
110        byteCodeArray[70] = new NoArgumentForm(70, "fstore_3");
111        byteCodeArray[71] = new NoArgumentForm(71, "dstore_0");
112        byteCodeArray[72] = new NoArgumentForm(72, "dstore_1");
113        byteCodeArray[73] = new NoArgumentForm(73, "dstore_2");
114        byteCodeArray[74] = new NoArgumentForm(74, "dstore_3");
115        byteCodeArray[75] = new NoArgumentForm(75, "astore_0");
116        byteCodeArray[76] = new NoArgumentForm(76, "astore_1");
117        byteCodeArray[77] = new NoArgumentForm(77, "astore_2");
118        byteCodeArray[78] = new NoArgumentForm(78, "astore_3");
119        byteCodeArray[79] = new NoArgumentForm(79, "iastore");
120        byteCodeArray[80] = new NoArgumentForm(80, "lastore");
121        byteCodeArray[81] = new NoArgumentForm(81, "fastore");
122        byteCodeArray[82] = new NoArgumentForm(82, "dastore");
123        byteCodeArray[83] = new NoArgumentForm(83, "aastore");
124        byteCodeArray[84] = new NoArgumentForm(84, "bastore");
125        byteCodeArray[85] = new NoArgumentForm(85, "castore");
126        byteCodeArray[86] = new NoArgumentForm(86, "sastore");
127        byteCodeArray[87] = new NoArgumentForm(87, "pop");
128        byteCodeArray[88] = new NoArgumentForm(88, "pop2");
129        byteCodeArray[89] = new NoArgumentForm(89, "dup");
130        byteCodeArray[90] = new NoArgumentForm(90, "dup_x1");
131        byteCodeArray[91] = new NoArgumentForm(91, "dup_x2");
132        byteCodeArray[92] = new NoArgumentForm(92, "dup2");
133        byteCodeArray[93] = new NoArgumentForm(93, "dup2_x1");
134        byteCodeArray[94] = new NoArgumentForm(94, "dup2_x2");
135        byteCodeArray[95] = new NoArgumentForm(95, "swap");
136        byteCodeArray[96] = new NoArgumentForm(96, "iadd");
137        byteCodeArray[97] = new NoArgumentForm(97, "ladd");
138        byteCodeArray[98] = new NoArgumentForm(98, "fadd");
139        byteCodeArray[99] = new NoArgumentForm(99, "dadd");
140        byteCodeArray[100] = new NoArgumentForm(100, "isub");
141        byteCodeArray[101] = new NoArgumentForm(101, "lsub");
142        byteCodeArray[102] = new NoArgumentForm(102, "fsub");
143        byteCodeArray[103] = new NoArgumentForm(103, "dsub");
144        byteCodeArray[104] = new NoArgumentForm(104, "imul");
145        byteCodeArray[105] = new NoArgumentForm(105, "lmul");
146        byteCodeArray[106] = new NoArgumentForm(106, "fmul");
147        byteCodeArray[107] = new NoArgumentForm(107, "dmul");
148        byteCodeArray[108] = new NoArgumentForm(108, "idiv");
149        byteCodeArray[109] = new NoArgumentForm(109, "ldiv");
150        byteCodeArray[110] = new NoArgumentForm(110, "fdiv");
151        byteCodeArray[111] = new NoArgumentForm(111, "ddiv");
152        byteCodeArray[112] = new NoArgumentForm(112, "irem");
153        byteCodeArray[113] = new NoArgumentForm(113, "lrem");
154        byteCodeArray[114] = new NoArgumentForm(114, "frem");
155        byteCodeArray[115] = new NoArgumentForm(115, "drem");
156        byteCodeArray[116] = new NoArgumentForm(116, "");
157        byteCodeArray[117] = new NoArgumentForm(117, "lneg");
158        byteCodeArray[118] = new NoArgumentForm(118, "fneg");
159        byteCodeArray[119] = new NoArgumentForm(119, "dneg");
160        byteCodeArray[120] = new NoArgumentForm(120, "ishl");
161        byteCodeArray[121] = new NoArgumentForm(121, "lshl");
162        byteCodeArray[122] = new NoArgumentForm(122, "ishr");
163        byteCodeArray[123] = new NoArgumentForm(123, "lshr");
164        byteCodeArray[124] = new NoArgumentForm(124, "iushr");
165        byteCodeArray[125] = new NoArgumentForm(125, "lushr");
166        byteCodeArray[126] = new NoArgumentForm(126, "iand");
167        byteCodeArray[127] = new NoArgumentForm(127, "land");
168        byteCodeArray[128] = new NoArgumentForm(128, "ior");
169        byteCodeArray[129] = new NoArgumentForm(129, "lor");
170        byteCodeArray[130] = new NoArgumentForm(130, "ixor");
171        byteCodeArray[131] = new NoArgumentForm(131, "lxor");
172        byteCodeArray[132] = new IincForm(132, "iinc", new int[] { 132, -1, -1 });
173        byteCodeArray[133] = new NoArgumentForm(133, "i2l");
174        byteCodeArray[134] = new NoArgumentForm(134, "i2f");
175        byteCodeArray[135] = new NoArgumentForm(135, "i2d");
176        byteCodeArray[136] = new NoArgumentForm(136, "l2i");
177        byteCodeArray[137] = new NoArgumentForm(137, "l2f");
178        byteCodeArray[138] = new NoArgumentForm(138, "l2d");
179        byteCodeArray[139] = new NoArgumentForm(139, "f2i");
180        byteCodeArray[140] = new NoArgumentForm(140, "f2l");
181        byteCodeArray[141] = new NoArgumentForm(141, "f2d");
182        byteCodeArray[142] = new NoArgumentForm(142, "d2i");
183        byteCodeArray[143] = new NoArgumentForm(143, "d2l");
184        byteCodeArray[144] = new NoArgumentForm(144, "d2f");
185        byteCodeArray[145] = new NoArgumentForm(145, "i2b");
186        byteCodeArray[146] = new NoArgumentForm(146, "i2c");
187        byteCodeArray[147] = new NoArgumentForm(147, "i2s");
188        byteCodeArray[148] = new NoArgumentForm(148, "lcmp");
189        byteCodeArray[149] = new NoArgumentForm(149, "fcmpl");
190        byteCodeArray[150] = new NoArgumentForm(150, "fcmpg");
191        byteCodeArray[151] = new NoArgumentForm(151, "dcmpl");
192        byteCodeArray[152] = new NoArgumentForm(152, "dcmpg");
193        byteCodeArray[153] = new LabelForm(153, "ifeq", new int[] { 153, -1, -1 });
194        byteCodeArray[154] = new LabelForm(154, "ifne", new int[] { 154, -1, -1 });
195        byteCodeArray[155] = new LabelForm(155, "iflt", new int[] { 155, -1, -1 });
196        byteCodeArray[156] = new LabelForm(156, "ifge", new int[] { 156, -1, -1 });
197        byteCodeArray[157] = new LabelForm(157, "ifgt", new int[] { 157, -1, -1 });
198        byteCodeArray[158] = new LabelForm(158, "ifle", new int[] { 158, -1, -1 });
199        byteCodeArray[159] = new LabelForm(159, "if_icmpeq", new int[] { 159, -1, -1 });
200        byteCodeArray[160] = new LabelForm(160, "if_icmpne", new int[] { 160, -1, -1 });
201        byteCodeArray[161] = new LabelForm(161, "if_icmplt", new int[] { 161, -1, -1 });
202        byteCodeArray[162] = new LabelForm(162, "if_icmpge", new int[] { 162, -1, -1 });
203        byteCodeArray[163] = new LabelForm(163, "if_icmpgt", new int[] { 163, -1, -1 });
204        byteCodeArray[164] = new LabelForm(164, "if_icmple", new int[] { 164, -1, -1 });
205        byteCodeArray[165] = new LabelForm(165, "if_acmpeq", new int[] { 165, -1, -1 });
206        byteCodeArray[166] = new LabelForm(166, "if_acmpne", new int[] { 166, -1, -1 });
207        byteCodeArray[167] = new LabelForm(167, "goto", new int[] { 167, -1, -1 });
208        byteCodeArray[168] = new LabelForm(168, "jsr", new int[] { 168, -1, -1 });
209        byteCodeArray[169] = new LocalForm(169, "ret", new int[] { 169, -1 });
210        byteCodeArray[170] = new TableSwitchForm(170, "tableswitch");
211        byteCodeArray[171] = new LookupSwitchForm(171, "lookupswitch");
212        byteCodeArray[172] = new NoArgumentForm(172, "ireturn");
213        byteCodeArray[173] = new NoArgumentForm(173, "lreturn");
214        byteCodeArray[174] = new NoArgumentForm(174, "freturn");
215        byteCodeArray[175] = new NoArgumentForm(175, "dreturn");
216        byteCodeArray[176] = new NoArgumentForm(176, "areturn");
217        byteCodeArray[177] = new NoArgumentForm(177, "return");
218        byteCodeArray[178] = new FieldRefForm(178, "getstatic", new int[] { 178, -1, -1 });
219        byteCodeArray[179] = new FieldRefForm(179, "putstatic", new int[] { 179, -1, -1 });
220        byteCodeArray[180] = new FieldRefForm(180, "getfield", new int[] { 180, -1, -1 });
221        byteCodeArray[181] = new FieldRefForm(181, "putfield", new int[] { 181, -1, -1 });
222        byteCodeArray[182] = new MethodRefForm(182, "invokevirtual", new int[] { 182, -1, -1 });
223        byteCodeArray[183] = new MethodRefForm(183, "invokespecial", new int[] { 183, -1, -1 });
224        byteCodeArray[184] = new MethodRefForm(184, "invokestatic", new int[] { 184, -1, -1 });
225        byteCodeArray[185] = new IMethodRefForm(185, "invokeinterface", new int[] { 185, -1, -1, /* count */-1, 0 });
226        byteCodeArray[186] = new NoArgumentForm(186, "xxxunusedxxx");
227        byteCodeArray[187] = new NewClassRefForm(187, "new", new int[] { 187, -1, -1 });
228        byteCodeArray[188] = new ByteForm(188, "newarray", new int[] { 188, -1 });
229        byteCodeArray[189] = new ClassRefForm(189, "anewarray", new int[] { 189, -1, -1 });
230        byteCodeArray[190] = new NoArgumentForm(190, "arraylength");
231        byteCodeArray[191] = new NoArgumentForm(191, "athrow");
232        byteCodeArray[192] = new ClassRefForm(192, "checkcast", new int[] { 192, -1, -1 });
233        byteCodeArray[193] = new ClassRefForm(193, "instanceof", new int[] { 193, -1, -1 });
234        byteCodeArray[194] = new NoArgumentForm(194, "monitorenter");
235        byteCodeArray[195] = new NoArgumentForm(195, "monitorexit");
236        byteCodeArray[196] = new WideForm(196, "wide");
237        byteCodeArray[197] = new MultiANewArrayForm(197, "multianewarray", new int[] { 197, -1, -1, -1 });
238        byteCodeArray[198] = new LabelForm(198, "ifnull", new int[] { 198, -1, -1 });
239        byteCodeArray[199] = new LabelForm(199, "ifnonnull", new int[] { 199, -1, -1 });
240        byteCodeArray[200] = new LabelForm(200, "goto_w", new int[] { 200, -1, -1, -1, -1 }, WIDENED);
241        byteCodeArray[201] = new LabelForm(201, "jsr_w", new int[] { 201, -1, -1, -1, -1 }, WIDENED);
242
243        // Extra ones defined by pack200
244        byteCodeArray[202] = new ThisFieldRefForm(202, "getstatic_this", new int[] { 178, -1, -1 });
245        byteCodeArray[203] = new ThisFieldRefForm(203, "putstatic_this", new int[] { 179, -1, -1 });
246        byteCodeArray[204] = new ThisFieldRefForm(204, "getfield_this", new int[] { 180, -1, -1 });
247        byteCodeArray[205] = new ThisFieldRefForm(205, "putfield_this", new int[] { 181, -1, -1 });
248        byteCodeArray[206] = new ThisMethodRefForm(206, "invokevirtual_this", new int[] { 182, -1, -1 });
249        byteCodeArray[207] = new ThisMethodRefForm(207, "invokespecial_this", new int[] { 183, -1, -1 });
250        byteCodeArray[208] = new ThisMethodRefForm(208, "invokestatic_this", new int[] { 184, -1, -1 });
251        byteCodeArray[209] = new ThisFieldRefForm(209, "aload_0_getstatic_this", new int[] { 42, 178, -1, -1 });
252        byteCodeArray[210] = new ThisFieldRefForm(210, "aload_0_putstatic_this", new int[] { 42, 179, -1, -1 });
253        byteCodeArray[211] = new ThisFieldRefForm(211, "aload_0_getfield_this", new int[] { 42, 180, -1, -1 });
254        byteCodeArray[212] = new ThisFieldRefForm(212, "aload_0_putfield_this", new int[] { 42, 181, -1, -1 });
255        byteCodeArray[213] = new ThisMethodRefForm(213, "aload_0_invokevirtual_this", new int[] { 42, 182, -1, -1 });
256        byteCodeArray[214] = new ThisMethodRefForm(214, "aload_0_invokespecial_this", new int[] { 42, 183, -1, -1 });
257        byteCodeArray[215] = new ThisMethodRefForm(215, "aload_0_invokestatic_this", new int[] { 42, 184, -1, -1 });
258        byteCodeArray[216] = new SuperFieldRefForm(216, "getstatic_super", new int[] { 178, -1, -1 });
259        byteCodeArray[217] = new SuperFieldRefForm(217, "putstatic_super", new int[] { 179, -1, -1 });
260        byteCodeArray[218] = new SuperFieldRefForm(218, "getfield_super", new int[] { 180, -1, -1 });
261        byteCodeArray[219] = new SuperFieldRefForm(219, "putfield_super", new int[] { 181, -1, -1 });
262        byteCodeArray[220] = new SuperMethodRefForm(220, "invokevirtual_super", new int[] { 182, -1, -1 });
263        byteCodeArray[221] = new SuperMethodRefForm(221, "invokespecial_super", new int[] { 183, -1, -1 });
264        byteCodeArray[222] = new SuperMethodRefForm(222, "invokestatic_super", new int[] { 184, -1, -1 });
265        byteCodeArray[223] = new SuperFieldRefForm(223, "aload_0_getstatic_super", new int[] { 42, 178, -1, -1 });
266        byteCodeArray[224] = new SuperFieldRefForm(224, "aload_0_putstatic_super", new int[] { 42, 179, -1, -1 });
267        byteCodeArray[225] = new SuperFieldRefForm(225, "aload_0_getfield_super", new int[] { 42, 180, -1, -1 });
268        byteCodeArray[226] = new SuperFieldRefForm(226, "aload_0_putfield_super", new int[] { 42, 181, -1, -1 });
269        byteCodeArray[227] = new SuperMethodRefForm(227, "aload_0_invokevirtual_super", new int[] { 42, 182, -1, -1 });
270        byteCodeArray[228] = new SuperMethodRefForm(228, "aload_0_invokespecial_super", new int[] { 42, 183, -1, -1 });
271        byteCodeArray[229] = new SuperMethodRefForm(229, "aload_0_invokestatic_super", new int[] { 42, 184, -1, -1 });
272        byteCodeArray[230] = new ThisInitMethodRefForm(230, "invokespecial_this_init", new int[] { 183, -1, -1 });
273        byteCodeArray[231] = new SuperInitMethodRefForm(231, "invokespecial_super_init", new int[] { 183, -1, -1 });
274        byteCodeArray[232] = new NewInitMethodRefForm(232, "invokespecial_new_init", new int[] { 183, -1, -1 });
275        byteCodeArray[233] = new NarrowClassRefForm(233, "cldc", new int[] { 18, -1 });
276        byteCodeArray[234] = new IntRefForm(234, "ildc", new int[] { 18, -1 });
277        byteCodeArray[235] = new FloatRefForm(235, "fldc", new int[] { 18, -1 });
278        byteCodeArray[236] = new NarrowClassRefForm(236, "cldc_w", new int[] { 19, -1, -1 }, WIDENED);
279        byteCodeArray[237] = new IntRefForm(237, "ildc_w", new int[] { 19, -1, -1 }, WIDENED);
280        byteCodeArray[238] = new FloatRefForm(238, "fldc_w", new int[] { 19, -1, -1 }, WIDENED);
281        byteCodeArray[239] = new DoubleForm(239, "dldc2_w", new int[] { 20, -1, -1 });
282
283        // Reserved bytecodes
284        byteCodeArray[254] = new NoArgumentForm(254, "impdep1");
285        byteCodeArray[255] = new NoArgumentForm(255, "impdep2");
286
287        // Bytecodes that aren't defined in the spec but are useful when
288        // unpacking (all must be >255)
289        // maybe wide versions of the others? etc.
290
291        // Put all the bytecodes in a HashMap so we can
292        // get them by either name or number
293        for (final ByteCodeForm byteCode : byteCodeArray) {
294            if (byteCode != null) {
295                byteCodesByName.put(byteCode.getName(), byteCode);
296            }
297        }
298    }
299
300    /**
301     * Gets a ByteCodeForm.
302     *
303     * @param opcode opcode index.
304     * @return the matching ByteCodeForm at the given opcode.
305     */
306    public static ByteCodeForm get(final int opcode) {
307        return byteCodeArray[opcode];
308    }
309
310    private final int opcode;
311    private final String name;
312    private final int[] rewrite;
313    private int firstOperandIndex;
314
315    private int operandLength;
316
317    /**
318     * Constructs a new instance with the specified opcode and name. Assume no rewrite.
319     *
320     * @param opcode index corresponding to the opcode's value.
321     * @param name   printable name of the opcode.
322     */
323    public ByteCodeForm(final int opcode, final String name) {
324        this(opcode, name, new int[] { opcode });
325    }
326
327    /**
328     * Constructs a new instance with the specified opcode, name, operandType and rewrite.
329     *
330     * @param opcode  index corresponding to the opcode's value.
331     * @param name    String printable name of the opcode.
332     * @param rewrite Operand positions (which will later be rewritten in ByteCodes) are indicated by -1.
333     */
334    public ByteCodeForm(final int opcode, final String name, final int[] rewrite) {
335        this.opcode = opcode;
336        this.name = name;
337        this.rewrite = rewrite;
338        calculateOperandPosition();
339    }
340
341    protected void calculateOperandPosition() {
342        firstOperandIndex = -1;
343        operandLength = -1;
344
345        // Find the first negative number in the rewrite array
346        int iterationIndex = 0;
347        while (iterationIndex < rewrite.length) {
348            if (rewrite[iterationIndex] < 0) {
349                // Found the first opcode to substitute
350                firstOperandIndex = iterationIndex;
351                iterationIndex = rewrite.length;
352            } else {
353                iterationIndex++;
354            }
355        }
356
357        if (firstOperandIndex == -1) {
358            // Nothing more to do since the opcode has no operands
359            return;
360        }
361
362        // Find the last negative number in the rewrite array
363        int lastOperandIndex = -1;
364        iterationIndex = firstOperandIndex;
365        while (iterationIndex < rewrite.length) {
366            if (rewrite[iterationIndex] < 0) {
367                lastOperandIndex = iterationIndex;
368            }
369            iterationIndex++;
370        }
371
372        // Now we have the first index and the last index.
373        final int difference = lastOperandIndex - firstOperandIndex;
374
375        // If last < first, something is wrong.
376        if (difference < 0) {
377            throw new Error("Logic error: not finding rewrite operands correctly");
378        }
379        operandLength = difference + 1;
380    }
381
382    public int firstOperandIndex() {
383        return firstOperandIndex;
384    }
385
386    /**
387     * The ByteCodeForm knows how to fix up a bytecode if it needs to be fixed up because it holds a Label bytecode.
388     *
389     * @param byteCode      a ByteCode to be fixed up
390     * @param codeAttribute a CodeAttribute used to determine how the ByteCode should be fixed up.
391     */
392    public void fixUpByteCodeTargets(final ByteCode byteCode, final CodeAttribute codeAttribute) {
393        // Most ByteCodeForms don't have any fixing up to do.
394    }
395
396    /**
397     * Gets the name.
398     *
399     * @return the name.
400     */
401    public String getName() {
402        return name;
403    }
404
405    /**
406     * Gets the opcode.
407     *
408     * @return the opcode.
409     */
410    public int getOpcode() {
411        return opcode;
412    }
413
414    /**
415     * Gets the rewrite array.
416     *
417     * @return the rewrite array.
418     */
419    public int[] getRewrite() {
420        return rewrite;
421    }
422
423    /**
424     * Gets a copy of the rewrite array.
425     *
426     * @return a copy of the rewrite array.
427     */
428    public int[] getRewriteCopy() {
429        return Arrays.copyOf(rewrite, rewrite.length);
430    }
431
432    /**
433     * This method will answer true if the receiver is a multi-bytecode instruction (such as aload0_putfield_super); otherwise, it will answer false.
434     *
435     * @return boolean true if multibytecode, false otherwise
436     */
437    public boolean hasMultipleByteCodes() {
438        // Currently, all multi-bytecode instructions
439        // begin with aload_0, so this is how we test.
440        if (rewrite.length > 1 && rewrite[0] == 42) {
441            // If there's an instruction (not a negative
442            // number, which is an operand) after the
443            // aload_0, it's a multibytecode instruction.
444            return rewrite[1] > 0;
445        }
446        return false;
447    }
448
449    /**
450     * Tests whether this instance has an operand.
451     *
452     * @return whether this instance has an operand.
453     */
454    public boolean hasNoOperand() {
455        return false;
456    }
457
458    public boolean nestedMustStartClassPool() {
459        return false;
460    }
461
462    /**
463     * Gets the operand length.
464     *
465     * @return the operand length.
466     */
467    public int operandLength() {
468        return operandLength;
469    }
470
471    /**
472     * Sets the rewrite of the byteCode.
473     *
474     * @param byteCode       ByteCode to be updated (!)
475     * @param operandManager OperandTable from which to draw info
476     * @param codeLength     Length of bytes (excluding this bytecode) from the beginning of the method. Used in calculating padding for some variable-length
477     *                       bytecodes (such as lookupswitch, tableswitch).
478     * @throws Pack200Exception if a type is not supported or an index not in the range [0, {@link Integer#MAX_VALUE}].
479     */
480    public abstract void setByteCodeOperands(ByteCode byteCode, OperandManager operandManager, int codeLength) throws Pack200Exception;
481
482    @Override
483    public String toString() {
484        return this.getClass().getName() + "(" + getName() + ")";
485    }
486}