vm/src/main/java/org/apidesign/vm4brwsr/ByteCodeToJavaScript.java
author Jaroslav Tulach <jaroslav.tulach@apidesign.org>
Fri, 28 Sep 2012 12:58:20 +0200
changeset 42 f30e2afc8ddb
parent 40 a36c17ff6331
child 46 b07c7c256771
permissions -rw-r--r--
Unifying the way method names are constructed so they work for arrays as well
     1 /*
     2 Java 4 Browser Bytecode Translator
     3 Copyright (C) 2012-2012 Jaroslav Tulach <jaroslav.tulach@apidesign.org>
     4 
     5 This program is free software: you can redistribute it and/or modify
     6 it under the terms of the GNU General Public License as published by
     7 the Free Software Foundation, version 2 of the License.
     8 
     9 This program is distributed in the hope that it will be useful,
    10 but WITHOUT ANY WARRANTY; without even the implied warranty of
    11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    12 GNU General Public License for more details.
    13 
    14 You should have received a copy of the GNU General Public License
    15 along with this program. Look for COPYING file in the top folder.
    16 If not, see http://opensource.org/licenses/GPL-2.0.
    17 */
    18 package org.apidesign.vm4brwsr;
    19 
    20 import java.io.IOException;
    21 import java.io.InputStream;
    22 import java.util.ArrayList;
    23 import java.util.Collection;
    24 import java.util.List;
    25 import static org.netbeans.modules.classfile.ByteCodes.*;
    26 import org.netbeans.modules.classfile.CPClassInfo;
    27 import org.netbeans.modules.classfile.CPEntry;
    28 import org.netbeans.modules.classfile.CPFieldInfo;
    29 import org.netbeans.modules.classfile.CPMethodInfo;
    30 import org.netbeans.modules.classfile.CPStringInfo;
    31 import org.netbeans.modules.classfile.ClassFile;
    32 import org.netbeans.modules.classfile.ClassName;
    33 import org.netbeans.modules.classfile.Code;
    34 import org.netbeans.modules.classfile.Method;
    35 import org.netbeans.modules.classfile.Parameter;
    36 import org.netbeans.modules.classfile.Variable;
    37 
    38 /** Translator of the code inside class files to JavaScript.
    39  *
    40  * @author Jaroslav Tulach <jtulach@netbeans.org>
    41  */
    42 public final class ByteCodeToJavaScript {
    43     private final ClassFile jc;
    44     private final Appendable out;
    45     private final Collection<? super String> references;
    46 
    47     private ByteCodeToJavaScript(
    48         ClassFile jc, Appendable out, Collection<? super String> references
    49     ) {
    50         this.jc = jc;
    51         this.out = out;
    52         this.references = references;
    53     }
    54 
    55     /**
    56      * Converts a given class file to a JavaScript version.
    57      *
    58      * @param classFile input stream with code of the .class file
    59      * @param out a {@link StringBuilder} or similar to generate the output to
    60      * @param references a write only collection where the system adds list of
    61      *   other classes that were referenced and should be loaded in order the
    62      *   generated JavaScript code works properly. The names are in internal 
    63      *   JVM form so String is <code>java/lang/String</code>. Can be <code>null</code>
    64      *   if one is not interested in knowing references
    65      * @throws IOException if something goes wrong during read or write or translating
    66      */
    67     
    68     public static void compile(
    69         InputStream classFile, Appendable out,
    70         Collection<? super String> references
    71     ) throws IOException {
    72         ClassFile jc = new ClassFile(classFile, true);
    73         ByteCodeToJavaScript compiler = new ByteCodeToJavaScript(
    74             jc, out, references
    75         );
    76         List<String> toInitilize = new ArrayList<String>();
    77         for (Method m : jc.getMethods()) {
    78             if (m.isStatic()) {
    79                 compiler.generateStaticMethod(m, toInitilize);
    80             } else {
    81                 compiler.generateInstanceMethod(m);
    82             }
    83         }
    84         for (Variable v : jc.getVariables()) {
    85             if (v.isStatic()) {
    86                 compiler.generateStaticField(v);
    87             }
    88         }
    89         
    90         final String className = jc.getName().getInternalName().replace('/', '_');
    91         out.append("\nfunction ").append(className);
    92         out.append("() {");
    93         for (Variable v : jc.getVariables()) {
    94             if (!v.isStatic()) {
    95                 out.append("\n  this." + v.getName() + " = 0;");
    96             }
    97         }
    98         out.append("\n}");
    99         ClassName sc = jc.getSuperClass();
   100         if (sc != null) {
   101             out.append("\n").append(className)
   102                .append(".prototype = new ").append(sc.getInternalName().replace('/', '_')).append(';');
   103         }
   104         for (Method m : jc.getMethods()) {
   105             if (!m.isStatic() && !m.isPrivate() && !m.getName().contains("<init>")) {
   106                 compiler.generateMethodReference("\n" + className + ".prototype.", m);
   107             }
   108         }
   109         out.append("\n" + className + ".prototype.$instOf_").append(className).append(" = true;");
   110         for (ClassName superInterface : jc.getInterfaces()) {
   111             out.append("\n" + className + ".prototype.$instOf_").append(superInterface.getInternalName().replace('/', '_')).append(" = true;");
   112         }
   113         for (String init : toInitilize) {
   114             out.append("\n").append(init).append("();");
   115         }
   116     }
   117     private void generateStaticMethod(Method m, List<String> toInitilize) throws IOException {
   118         final String mn = findMethodName(m);
   119         out.append("\nfunction ").append(
   120             jc.getName().getInternalName().replace('/', '_')
   121         ).append('_').append(mn);
   122         if (mn.equals("classV")) {
   123             toInitilize.add(jc.getName().getInternalName().replace('/', '_') + '_' + mn);
   124         }
   125         out.append('(');
   126         String space = "";
   127         List<Parameter> args = m.getParameters();
   128         for (int index = 0, i = 0; i < args.size(); i++) {
   129             out.append(space);
   130             out.append("arg").append(String.valueOf(index));
   131             space = ",";
   132             final String desc = findDescriptor(args.get(i).getDescriptor());
   133             if ("D".equals(desc) || "J".equals(desc)) {
   134                 index += 2;
   135             } else {
   136                 index++;
   137             }
   138         }
   139         out.append(") {").append("\n");
   140         final Code code = m.getCode();
   141         if (code != null) {
   142             int len = code.getMaxLocals();
   143             for (int index = args.size(), i = args.size(); i < len; i++) {
   144                 out.append("  var ");
   145                 out.append("arg").append(String.valueOf(i)).append(";\n");
   146             }
   147             out.append("  var stack = new Array();\n");
   148             produceCode(code.getByteCodes());
   149         } else {
   150             out.append("  /* no code found for ").append(m.getTypeSignature()).append(" */\n");
   151         }
   152         out.append("}");
   153     }
   154     
   155     private void generateMethodReference(String prefix, Method m) throws IOException {
   156         final String name = findMethodName(m);
   157         out.append(prefix).append(name).append(" = ")
   158            .append(jc.getName().getInternalName().replace('/', '_'))
   159            .append('_').append(name).append(";");
   160     }
   161     
   162     private void generateInstanceMethod(Method m) throws IOException {
   163         out.append("\nfunction ").append(
   164             jc.getName().getInternalName().replace('/', '_')
   165         ).append('_').append(findMethodName(m));
   166         out.append("(arg0");
   167         String space = ",";
   168         List<Parameter> args = m.getParameters();
   169         for (int index = 1, i = 0; i < args.size(); i++) {
   170             out.append(space);
   171             out.append("arg").append(String.valueOf(index));
   172             final String desc = findDescriptor(args.get(i).getDescriptor());
   173             if ("D".equals(desc) || "J".equals(desc)) {
   174                 index += 2;
   175             } else {
   176                 index++;
   177             }
   178         }
   179         out.append(") {").append("\n");
   180         final Code code = m.getCode();
   181         if (code != null) {
   182             int len = code.getMaxLocals();
   183             for (int index = args.size(), i = args.size(); i < len; i++) {
   184                 out.append("  var ");
   185                 out.append("arg").append(String.valueOf(i + 1)).append(";\n");
   186             }
   187             out.append(";\n  var stack = new Array(");
   188             out.append(Integer.toString(code.getMaxStack()));
   189             out.append(");\n");
   190             produceCode(code.getByteCodes());
   191         } else {
   192             out.append("  /* no code found for ").append(m.getTypeSignature()).append(" */\n");
   193         }
   194         out.append("}");
   195     }
   196 
   197     private void produceCode(byte[] byteCodes) throws IOException {
   198         out.append("\n  var gt = 0;\n  for(;;) switch(gt) {\n");
   199         for (int i = 0; i < byteCodes.length; i++) {
   200             int prev = i;
   201             out.append("    case " + i).append(": ");
   202             final int c = (byteCodes[i] + 256) % 256;
   203             switch (c) {
   204                 case bc_aload_0:
   205                 case bc_iload_0:
   206                 case bc_lload_0:
   207                 case bc_fload_0:
   208                 case bc_dload_0:
   209                     out.append("stack.push(arg0);");
   210                     break;
   211                 case bc_aload_1:
   212                 case bc_iload_1:
   213                 case bc_lload_1:
   214                 case bc_fload_1:
   215                 case bc_dload_1:
   216                     out.append("stack.push(arg1);");
   217                     break;
   218                 case bc_aload_2:
   219                 case bc_iload_2:
   220                 case bc_lload_2:
   221                 case bc_fload_2:
   222                 case bc_dload_2:
   223                     out.append("stack.push(arg2);");
   224                     break;
   225                 case bc_aload_3:
   226                 case bc_iload_3:
   227                 case bc_lload_3:
   228                 case bc_fload_3:
   229                 case bc_dload_3:
   230                     out.append("stack.push(arg3);");
   231                     break;
   232                 case bc_iload:
   233                 case bc_lload:
   234                 case bc_fload:
   235                 case bc_dload:
   236                 case bc_aload: {
   237                     final int indx = (byteCodes[++i] + 256) % 256;
   238                     out.append("stack.push(arg").append(indx + ");");
   239                     break;
   240                 }
   241                 case bc_istore:
   242                 case bc_lstore:
   243                 case bc_fstore:
   244                 case bc_dstore:
   245                 case bc_astore: {
   246                     final int indx = (byteCodes[++i] + 256) % 256;
   247                     out.append("arg" + indx).append(" = stack.pop()");
   248                     break;
   249                 }
   250                 case bc_astore_0:
   251                 case bc_istore_0:
   252                 case bc_lstore_0:
   253                 case bc_fstore_0:
   254                 case bc_dstore_0:
   255                     out.append("arg0 = stack.pop();");
   256                     break;
   257                 case bc_astore_1:
   258                 case bc_istore_1:
   259                 case bc_lstore_1:
   260                 case bc_fstore_1:
   261                 case bc_dstore_1:
   262                     out.append("arg1 = stack.pop();");
   263                     break;
   264                 case bc_astore_2:
   265                 case bc_istore_2:
   266                 case bc_lstore_2:
   267                 case bc_fstore_2:
   268                 case bc_dstore_2:
   269                     out.append("arg2 = stack.pop();");
   270                     break;
   271                 case bc_astore_3:
   272                 case bc_istore_3:
   273                 case bc_lstore_3:
   274                 case bc_fstore_3:
   275                 case bc_dstore_3:
   276                     out.append("arg3 = stack.pop();");
   277                     break;
   278                 case bc_iadd:
   279                 case bc_ladd:
   280                 case bc_fadd:
   281                 case bc_dadd:
   282                     out.append("stack.push(stack.pop() + stack.pop());");
   283                     break;
   284                 case bc_isub:
   285                 case bc_lsub:
   286                 case bc_fsub:
   287                 case bc_dsub:
   288                     out.append("{ var tmp = stack.pop(); stack.push(stack.pop() - tmp); }");
   289                     break;
   290                 case bc_imul:
   291                 case bc_lmul:
   292                 case bc_fmul:
   293                 case bc_dmul:
   294                     out.append("stack.push(stack.pop() * stack.pop());");
   295                     break;
   296                 case bc_idiv:
   297                 case bc_ldiv:
   298                     out.append("{ var tmp = stack.pop(); stack.push(Math.floor(stack.pop() / tmp)); }");
   299                     break;
   300                 case bc_fdiv:
   301                 case bc_ddiv:
   302                     out.append("{ var tmp = stack.pop(); stack.push(stack.pop() / tmp); }");
   303                     break;
   304                 case bc_iand:
   305                 case bc_land:
   306                     out.append("stack.push(stack.pop() & stack.pop());");
   307                     break;
   308                 case bc_ior:
   309                 case bc_lor:
   310                     out.append("stack.push(stack.pop() | stack.pop());");
   311                     break;
   312                 case bc_ixor:
   313                 case bc_lxor:
   314                     out.append("stack.push(stack.pop() ^ stack.pop());");
   315                     break;
   316                 case bc_iinc: {
   317                     final int varIndx = (byteCodes[++i] + 256) % 256;
   318                     final int incrBy = (byteCodes[++i] + 256) % 256;
   319                     if (incrBy == 1) {
   320                         out.append("arg" + varIndx).append("++;");
   321                     } else {
   322                         out.append("arg" + varIndx).append(" += " + incrBy).append(";");
   323                     }
   324                     break;
   325                 }
   326                 case bc_return:
   327                     out.append("return;");
   328                     break;
   329                 case bc_ireturn:
   330                 case bc_lreturn:
   331                 case bc_freturn:
   332                 case bc_dreturn:
   333                 case bc_areturn:
   334                     out.append("return stack.pop();");
   335                     break;
   336                 case bc_i2l:
   337                 case bc_i2f:
   338                 case bc_i2d:
   339                 case bc_l2i:
   340                     // max int check?
   341                 case bc_l2f:
   342                 case bc_l2d:
   343                 case bc_f2d:
   344                 case bc_d2f:
   345                     out.append("/* number conversion */");
   346                     break;
   347                 case bc_f2i:
   348                 case bc_f2l:
   349                 case bc_d2i:
   350                 case bc_d2l:
   351                     out.append("stack.push(Math.floor(stack.pop()));");
   352                     break;
   353                 case bc_i2b:
   354                 case bc_i2c:
   355                 case bc_i2s:
   356                     out.append("/* number conversion */");
   357                     break;
   358                 case bc_iconst_0:
   359                 case bc_dconst_0:
   360                 case bc_lconst_0:
   361                 case bc_fconst_0:
   362                     out.append("stack.push(0);");
   363                     break;
   364                 case bc_iconst_1:
   365                 case bc_lconst_1:
   366                 case bc_fconst_1:
   367                 case bc_dconst_1:
   368                     out.append("stack.push(1);");
   369                     break;
   370                 case bc_iconst_2:
   371                 case bc_fconst_2:
   372                     out.append("stack.push(2);");
   373                     break;
   374                 case bc_iconst_3:
   375                     out.append("stack.push(3);");
   376                     break;
   377                 case bc_iconst_4:
   378                     out.append("stack.push(4);");
   379                     break;
   380                 case bc_iconst_5:
   381                     out.append("stack.push(5);");
   382                     break;
   383                 case bc_ldc: {
   384                     int indx = byteCodes[++i];
   385                     CPEntry entry = jc.getConstantPool().get(indx);
   386                     String v = encodeConstant(entry);
   387                     out.append("stack.push(").append(v).append(");");
   388                     break;
   389                 }
   390                 case bc_ldc_w:
   391                 case bc_ldc2_w: {
   392                     int indx = readIntArg(byteCodes, i);
   393                     CPEntry entry = jc.getConstantPool().get(indx);
   394                     i += 2;
   395                     String v = encodeConstant(entry);
   396                     out.append("stack.push(").append(v).append(");");
   397                     break;
   398                 }
   399                 case bc_lcmp:
   400                 case bc_fcmpl:
   401                 case bc_fcmpg:
   402                 case bc_dcmpl:
   403                 case bc_dcmpg: {
   404                     out.append("{ var delta = stack.pop() - stack.pop(); stack.push(delta < 0 ?-1 : (delta == 0 ? 0 : 1)); }");
   405                     break;
   406                 }
   407                 case bc_if_icmpeq: {
   408                     i = generateIf(byteCodes, i, "==");
   409                     break;
   410                 }
   411                 case bc_ifeq: {
   412                     int indx = i + readIntArg(byteCodes, i);
   413                     out.append("if (stack.pop() == 0) { gt = " + indx);
   414                     out.append("; continue; }");
   415                     i += 2;
   416                     break;
   417                 }
   418                 case bc_ifne: {
   419                     int indx = i + readIntArg(byteCodes, i);
   420                     out.append("if (stack.pop() != 0) { gt = " + indx);
   421                     out.append("; continue; }");
   422                     i += 2;
   423                     break;
   424                 }
   425                 case bc_iflt: {
   426                     int indx = i + readIntArg(byteCodes, i);
   427                     out.append("if (stack.pop() < 0) { gt = " + indx);
   428                     out.append("; continue; }");
   429                     i += 2;
   430                     break;
   431                 }
   432                 case bc_ifle: {
   433                     int indx = i + readIntArg(byteCodes, i);
   434                     out.append("if (stack.pop() <= 0) { gt = " + indx);
   435                     out.append("; continue; }");
   436                     i += 2;
   437                     break;
   438                 }
   439                 case bc_ifgt: {
   440                     int indx = i + readIntArg(byteCodes, i);
   441                     out.append("if (stack.pop() > 0) { gt = " + indx);
   442                     out.append("; continue; }");
   443                     i += 2;
   444                     break;
   445                 }
   446                 case bc_ifge: {
   447                     int indx = i + readIntArg(byteCodes, i);
   448                     out.append("if (stack.pop() >= 0) { gt = " + indx);
   449                     out.append("; continue; }");
   450                     i += 2;
   451                     break;
   452                 }
   453                 case bc_ifnonnull: {
   454                     int indx = i + readIntArg(byteCodes, i);
   455                     out.append("if (stack.pop()) { gt = " + indx);
   456                     out.append("; continue; }");
   457                     i += 2;
   458                     break;
   459                 }
   460                 case bc_ifnull: {
   461                     int indx = i + readIntArg(byteCodes, i);
   462                     out.append("if (!stack.pop()) { gt = " + indx);
   463                     out.append("; continue; }");
   464                     i += 2;
   465                     break;
   466                 }
   467                 case bc_if_icmpne:
   468                     i = generateIf(byteCodes, i, "!=");
   469                     break;
   470                 case bc_if_icmplt:
   471                     i = generateIf(byteCodes, i, ">");
   472                     break;
   473                 case bc_if_icmple:
   474                     i = generateIf(byteCodes, i, ">=");
   475                     break;
   476                 case bc_if_icmpgt:
   477                     i = generateIf(byteCodes, i, "<");
   478                     break;
   479                 case bc_if_icmpge:
   480                     i = generateIf(byteCodes, i, "<=");
   481                     break;
   482                 case bc_goto: {
   483                     int indx = i + readIntArg(byteCodes, i);
   484                     out.append("gt = " + indx).append("; continue;");
   485                     i += 2;
   486                     break;
   487                 }
   488                 case bc_invokeinterface:
   489                 case bc_invokevirtual:
   490                     i = invokeVirtualMethod(byteCodes, i);
   491                     break;
   492                 case bc_invokespecial:
   493                     i = invokeStaticMethod(byteCodes, i, false);
   494                     break;
   495                 case bc_invokestatic:
   496                     i = invokeStaticMethod(byteCodes, i, true);
   497                     break;
   498                 case bc_new: {
   499                     int indx = readIntArg(byteCodes, i);
   500                     CPClassInfo ci = jc.getConstantPool().getClass(indx);
   501                     out.append("stack.push(");
   502                     out.append("new ").append(ci.getClassName().getInternalName().replace('/','_'));
   503                     out.append(");");
   504                     addReference(ci.getClassName().getInternalName());
   505                     i += 2;
   506                     break;
   507                 }
   508                 case bc_newarray: {
   509                     int type = byteCodes[i++];
   510                     out.append("stack.push(new Array(stack.pop()));");
   511                     break;
   512                 }
   513                 case bc_anewarray: {
   514                     i += 2; // skip type of array
   515                     out.append("stack.push(new Array(stack.pop()));");
   516                     break;
   517                 }
   518                 case bc_arraylength:
   519                     out.append("stack.push(stack.pop().length);");
   520                     break;
   521                 case bc_iastore:
   522                 case bc_lastore:
   523                 case bc_fastore:
   524                 case bc_dastore:
   525                 case bc_aastore:
   526                 case bc_bastore:
   527                 case bc_castore:
   528                 case bc_sastore: {
   529                     out.append("{ var value = stack.pop(); var indx = stack.pop(); stack.pop()[indx] = value; }");
   530                     break;
   531                 }
   532                 case bc_iaload:
   533                 case bc_laload:
   534                 case bc_faload:
   535                 case bc_daload:
   536                 case bc_aaload:
   537                 case bc_baload:
   538                 case bc_caload:
   539                 case bc_saload: {
   540                     out.append("{ var indx = stack.pop(); stack.push(stack.pop()[indx]); }");
   541                     break;
   542                 }
   543                 case bc_dup:
   544                     out.append("stack.push(stack[stack.length - 1]);");
   545                     break;
   546                 case bc_bipush:
   547                     out.append("stack.push(" + byteCodes[++i] + ");");
   548                     break;
   549                 case bc_sipush:
   550                     out.append("stack.push(" + readIntArg(byteCodes, i) + ");");
   551                     i += 2;
   552                     break;
   553                 case bc_getfield: {
   554                     int indx = readIntArg(byteCodes, i);
   555                     CPFieldInfo fi = (CPFieldInfo) jc.getConstantPool().get(indx);
   556                     out.append("stack.push(stack.pop().").append(fi.getFieldName()).append(");");
   557                     i += 2;
   558                     break;
   559                 }
   560                 case bc_getstatic: {
   561                     int indx = readIntArg(byteCodes, i);
   562                     CPFieldInfo fi = (CPFieldInfo) jc.getConstantPool().get(indx);
   563                     final String in = fi.getClassName().getInternalName();
   564                     out.append("stack.push(").append(in.replace('/', '_'));
   565                     out.append('_').append(fi.getFieldName()).append(");");
   566                     i += 2;
   567                     addReference(in);
   568                     break;
   569                 }
   570                 case bc_putstatic: {
   571                     int indx = readIntArg(byteCodes, i);
   572                     CPFieldInfo fi = (CPFieldInfo) jc.getConstantPool().get(indx);
   573                     final String in = fi.getClassName().getInternalName();
   574                     out.append(in.replace('/', '_'));
   575                     out.append('_').append(fi.getFieldName()).append(" = stack.pop();");
   576                     i += 2;
   577                     addReference(in);
   578                     break;
   579                 }
   580                 case bc_putfield: {
   581                     int indx = readIntArg(byteCodes, i);
   582                     CPFieldInfo fi = (CPFieldInfo) jc.getConstantPool().get(indx);
   583                     out.append("{ var v = stack.pop(); stack.pop().")
   584                        .append(fi.getFieldName()).append(" = v; }");
   585                     i += 2;
   586                     break;
   587                 }
   588                 case bc_checkcast: {
   589                     int indx = readIntArg(byteCodes, i);
   590                     CPClassInfo ci = jc.getConstantPool().getClass(indx);
   591                     final String type = ci.getClassName().getType();
   592                     if (!type.startsWith("[")) {
   593                         // no way to check arrays right now
   594                         out.append("if(stack[stack.length - 1].$instOf_")
   595                            .append(type.replace('/', '_'))
   596                            .append(" != 1) throw {};"); // XXX proper exception
   597                     }
   598                     i += 2;
   599                     break;
   600                 }
   601                 case bc_instanceof: {
   602                     int indx = readIntArg(byteCodes, i);
   603                     CPClassInfo ci = jc.getConstantPool().getClass(indx);
   604                     out.append("stack.push(stack.pop().$instOf_")
   605                        .append(ci.getClassName().getInternalName().replace('/', '_'))
   606                        .append(" ? 1 : 0);");
   607                     i += 2;
   608                     break;
   609                 }
   610                     
   611             }
   612             out.append(" //");
   613             for (int j = prev; j <= i; j++) {
   614                 out.append(" ");
   615                 final int cc = (byteCodes[j] + 256) % 256;
   616                 out.append(Integer.toString(cc));
   617             }
   618             out.append("\n");
   619         }
   620         out.append("  }\n");
   621     }
   622 
   623     private int generateIf(byte[] byteCodes, int i, final String test) throws IOException {
   624         int indx = i + readIntArg(byteCodes, i);
   625         out.append("if (stack.pop() ").append(test).append(" stack.pop()) { gt = " + indx);
   626         out.append("; continue; }");
   627         return i + 2;
   628     }
   629 
   630     private int readIntArg(byte[] byteCodes, int offsetInstruction) {
   631         final int indxHi = byteCodes[offsetInstruction + 1] << 8;
   632         final int indxLo = byteCodes[offsetInstruction + 2];
   633         return (indxHi & 0xffffff00) | (indxLo & 0xff);
   634     }
   635     
   636     private static int countArgs(String descriptor, boolean[] hasReturnType, StringBuilder sig) {
   637         int cnt = 0;
   638         int i = 0;
   639         Boolean count = null;
   640         boolean array = false;
   641         int firstPos = sig.length();
   642         while (i < descriptor.length()) {
   643             char ch = descriptor.charAt(i++);
   644             switch (ch) {
   645                 case '(':
   646                     count = true;
   647                     continue;
   648                 case ')':
   649                     count = false;
   650                     continue;
   651                 case 'A':
   652                     array = true;
   653                     break;
   654                 case 'B': 
   655                 case 'C': 
   656                 case 'D': 
   657                 case 'F': 
   658                 case 'I': 
   659                 case 'J': 
   660                 case 'S': 
   661                 case 'Z': 
   662                     if (count) {
   663                         cnt++;
   664                         if (array) {
   665                             sig.append('A');
   666                         }
   667                         sig.append(ch);
   668                     } else {
   669                         hasReturnType[0] = true;
   670                         sig.insert(firstPos, ch);
   671                         if (array) {
   672                             sig.insert(firstPos, 'A');
   673                         }
   674                     }
   675                     continue;
   676                 case 'V': 
   677                     assert !count;
   678                     hasReturnType[0] = false;
   679                     sig.insert(firstPos, 'V');
   680                     continue;
   681                 case 'L':
   682                     int next = descriptor.indexOf(';', i);
   683                     if (count) {
   684                         cnt++;
   685                         if (array) {
   686                             sig.append('A');
   687                         }
   688                         sig.append(ch);
   689                         sig.append(descriptor.substring(i, next).replace('/', '_'));
   690                     } else {
   691                         sig.insert(firstPos, descriptor.substring(i, next).replace('/', '_'));
   692                         sig.insert(firstPos, ch);
   693                         if (array) {
   694                             sig.insert(firstPos, 'A');
   695                         }
   696                         hasReturnType[0] = true;
   697                     }
   698                     i = next + 1;
   699                     continue;
   700                 case '[':
   701                     //arrays++;
   702                     continue;
   703                 default:
   704                     break; // invalid character
   705             }
   706         }
   707         return cnt;
   708     }
   709 
   710     private void generateStaticField(Variable v) throws IOException {
   711         out.append("\nvar ")
   712            .append(jc.getName().getInternalName().replace('/', '_'))
   713            .append('_').append(v.getName()).append(" = 0;");
   714     }
   715 
   716     private String findMethodName(Method m) {
   717         StringBuilder name = new StringBuilder();
   718         String descr = m.getDescriptor();
   719         if ("<init>".equals(m.getName())) { // NOI18N
   720             name.append("cons"); // NOI18N
   721         } else if ("<clinit>".equals(m.getName())) { // NOI18N
   722             name.append("class"); // NOI18N
   723         } else {
   724             name.append(m.getName());
   725         } 
   726         
   727         boolean hasReturn[] = { false };
   728         countArgs(findDescriptor(m.getDescriptor()), hasReturn, name);
   729         return name.toString();
   730     }
   731 
   732     private String findMethodName(CPMethodInfo mi, int[] cnt, boolean[] hasReturn) {
   733         StringBuilder name = new StringBuilder();
   734         String descr = mi.getDescriptor();
   735         if ("<init>".equals(mi.getName())) { // NOI18N
   736             name.append("cons"); // NOI18N
   737         } else {
   738             name.append(mi.getName());
   739         }
   740         cnt[0] = countArgs(findDescriptor(mi.getDescriptor()), hasReturn, name);
   741         return name.toString();
   742     }
   743 
   744     private int invokeStaticMethod(byte[] byteCodes, int i, boolean isStatic)
   745     throws IOException {
   746         int methodIndex = readIntArg(byteCodes, i);
   747         CPMethodInfo mi = (CPMethodInfo) jc.getConstantPool().get(methodIndex);
   748         boolean[] hasReturn = { false };
   749         int[] cnt = { 0 };
   750         String mn = findMethodName(mi, cnt, hasReturn);
   751         out.append("{ ");
   752         for (int j = cnt[0] - 1; j >= 0; j--) {
   753             out.append("var v" + j).append(" = stack.pop(); ");
   754         }
   755         
   756         if (hasReturn[0]) {
   757             out.append("stack.push(");
   758         }
   759         final String in = mi.getClassName().getInternalName();
   760         out.append(in.replace('/', '_'));
   761         out.append('_');
   762         out.append(mn);
   763         out.append('(');
   764         String sep = "";
   765         if (!isStatic) {
   766             out.append("stack.pop()");
   767             sep = ", ";
   768         }
   769         for (int j = 0; j < cnt[0]; j++) {
   770             out.append(sep);
   771             out.append("v" + j);
   772             sep = ", ";
   773         }
   774         out.append(")");
   775         if (hasReturn[0]) {
   776             out.append(")");
   777         }
   778         out.append("; }");
   779         i += 2;
   780         addReference(in);
   781         return i;
   782     }
   783     private int invokeVirtualMethod(byte[] byteCodes, int i)
   784     throws IOException {
   785         int methodIndex = readIntArg(byteCodes, i);
   786         CPMethodInfo mi = (CPMethodInfo) jc.getConstantPool().get(methodIndex);
   787         boolean[] hasReturn = { false };
   788         int[] cnt = { 0 };
   789         String mn = findMethodName(mi, cnt, hasReturn);
   790         out.append("{ ");
   791         for (int j = cnt[0] - 1; j >= 0; j--) {
   792             out.append("var v" + j).append(" = stack.pop(); ");
   793         }
   794         out.append("var self = stack.pop(); ");
   795         if (hasReturn[0]) {
   796             out.append("stack.push(");
   797         }
   798         out.append("self.");
   799         out.append(mn);
   800         out.append('(');
   801         out.append("self");
   802         for (int j = 0; j < cnt[0]; j++) {
   803             out.append(", ");
   804             out.append("v" + j);
   805         }
   806         out.append(")");
   807         if (hasReturn[0]) {
   808             out.append(")");
   809         }
   810         out.append("; }");
   811         i += 2;
   812         return i;
   813     }
   814     
   815     private void addReference(String cn) {
   816         if (references != null) {
   817             references.add(cn);
   818         }
   819     }
   820 
   821     private void outType(String d, StringBuilder out) {
   822         int arr = 0;
   823         while (d.charAt(0) == '[') {
   824             out.append('A');
   825             d = d.substring(1);
   826         }
   827         if (d.charAt(0) == 'L') {
   828             assert d.charAt(d.length() - 1) == ';';
   829             out.append(d.replace('/', '_').substring(0, d.length() - 1));
   830         } else {
   831             out.append(d);
   832         }
   833     }
   834 
   835     private String encodeConstant(CPEntry entry) {
   836         final String v;
   837         if (entry instanceof CPStringInfo) {
   838             v = "\"" + entry.getValue().toString().replace("\"", "\\\"") + "\"";
   839         } else {
   840             v = entry.getValue().toString();
   841         }
   842         return v;
   843     }
   844 
   845     private String findDescriptor(String d) {
   846         return d.replace('[', 'A');
   847     }
   848 }