gpcp/J2CPS/SymbolFile.java

/**********************************************************************/
/*                  Symbol File class for j2cps                       */
/*                                                                    */   
/*  (c) copyright QUT, John Gough 2000-2012, John Gough, 2012-2017    */ 
/**********************************************************************/
package j2cps;

import java.io.*;
import java.util.ArrayList;
import j2cpsfiles.j2cpsfiles;

class SymbolFile {
 
/************************************************************************/
/*             Symbol file reading/writing                              */
/************************************************************************/
  // Collected syntax ---
  // 
  // SymFile    = Header [String (falSy | truSy)]
  //		{Import | Constant | Variable | Type | Procedure} 
  //		TypeList Key.
  // Header     = magic modSy Name.
  // Import     = impSy Name [String] Key.
  // Constant   = conSy Name Literal.
  // Variable   = varSy Name TypeOrd.
  // -------- Note --------
  //  The Type syntax is used to declare the type ordinals 
  //  that are used for all references to this module's types.
  // ----------------------
  // Type       = typSy Name TypeOrd.
  // Procedure  = prcSy Name [String] [truSy] FormalType.
  // Method     = mthSy Name Byte Byte TypeOrd [String] FormalType.
  // FormalType = [retSy TypeOrd] frmSy {parSy Byte TypeOrd} endFm.
  // TypeOrd    = ordinal.
  // -------- Note --------
  //  TypeHeaders are used in the symbol file format to 
  //  denote a type that is defined here or is imported.
  //  For types defined here, the ordinal is that declard
  //  in the definition section of this symbol file.
  //  For imported types the first ordinal is the ordinal
  //  declared in the definition section, the second ordinal
  //  is the index into the package import list.
  // ----------------------
  // TypeHeader = tDefS Ord [fromS Ord Name].
  // TypeList   = start {Array | Record | Pointer | ProcType | 
  //                     NamedType | Enum} close.
  // Array      = TypeHeader arrSy TypeOrd (Byte | Number | ) endAr.
  // Pointer    = TypeHeader ptrSy TypeOrd.
  // ProcType   = TypeHeader pTpSy FormalType.
  // EventType  = TypeHeader evtSy FormalType.
  // Record     = TypeHeader recSy recAtt [truSy | falSy] [basSy TypeOrd] 
  //              [iFcSy basSy TypeOrd {basSy TypeOrd}]
  //              {Name TypeOrd} {Method} {Statics} endRc.
  // Statics    = ( Constant | Variable | Procedure ).
  // Enum       = TypeHeader eTpSy { Constant } endRc.
  // NamedType  = TypeHeader. 
  // Name       = namSy byte UTFstring.
  // Literal    = Number | String | Set | Char | Real | falSy | truSy.
  // Byte       = bytSy byte.
  // String     = strSy UTFstring.
  // Number     = numSy java.lang.long.
  // Real       = fltSy java.lang.double.
  // Set        = setSy java.lang.int.
  // Key        = keySy java.lang.int.
  // Char       = chrSy java.lang.char.
  //
  // Notes on the syntax:
  // All record types must have a Name field, even though this is often
  // redundant.  The issue is that every record type (including those that
  // are anonymous in CP) corresponds to a Java class, and the definer 
  // and the user of the class _must_ agree on the JVM name of the class.
  // The same reasoning applies to procedure types, which must have equal
  // interface names in all modules.
  //

  static final String[] mthAtt = {"", ",NEW", ",ABSTRACT", ",NEW,ABSTRACT",
                                  ",EMPTY", ",NEW,EMPTY",
                                  ",EXTENSIBLE", ",NEW,EXTENSIBLE"};
  static final String[] recAtt = {"RECORD ", "ABSTRACT RECORD ",
                                  "LIMITED RECORD ", "EXTENSIBLE RECORD "};
  static final String[] mark = {"", "*", "-", "!"};
  static final String[] varMark = {"", "IN", "OUT", "VAR"};

  //private static final String spaces = "         ";
  //private static final String recEndSpace = "      "; 

  static final int modSy = (int) 'H';
  static final int namSy = (int) '$';
  static final int bytSy = (int) '\\';
  static final int numSy = (int) '#';
  static final int chrSy = (int) 'c';
  static final int strSy = (int) 's';
  static final int fltSy = (int) 'r';
  static final int falSy = (int) '0';
  static final int truSy = (int) '1';
  static final int impSy = (int) 'I';
  static final int setSy = (int) 'S';
  static final int keySy = (int) 'K';
  static final int conSy = (int) 'C';
  static final int typSy = (int) 'T';
  static final int tDefS = (int) 't';
  static final int prcSy = (int) 'P';
  static final int retSy = (int) 'R';
  static final int mthSy = (int) 'M';
  static final int varSy = (int) 'V';
  static final int parSy = (int) 'p';
  static final int iFcSy = (int) '~';
  
  static final int start = (int) '&';
  static final int close = (int) '!';
  
  static final int recSy = (int) '{';
  static final int endRc = (int) '}';
  static final int frmSy = (int) '(';
  static final int fromS = (int) '@';
  static final int endFm = (int) ')';
  static final int arrSy = (int) '[';
  static final int endAr = (int) ']';
  static final int pTpSy = (int) '%';
  static final int evtSy = (int) 'v';
  static final int ptrSy = (int) '^';
  static final int basSy = (int) '+';
  static final int eTpSy = (int) 'e';
  
  static final int magic = 0xdeadd0d0;

  static final int prvMode = 0;
  static final int pubMode = 1;
  static final int rdoMode = 2;
  static final int protect = 3;

  private static final int initTypeListSize = 128;
  public static TypeDesc[] typeList = new TypeDesc[initTypeListSize];
  private static int nextType = TypeDesc.ordT;
  private static int tListIx = 0;
  private static int sSym = 0;
  private static int acc = 0;
  private static String name;
  private static int iVal;
  private static long lVal;
  private static int tOrd;
  private static char cVal;
  private static double dVal;
  private static DataInputStream in;
  
  private static int count = 0;
  private static PackageDesc target = null;
  private static ArrayList<PackageDesc> imps = null;
  
// Symbol file writing

  static void writeName(DataOutputStream out,int access, String name) 
                                                            throws IOException{
    out.writeByte(namSy);
    if (ConstantPool.isPublic(access))   { 
        out.writeByte(pubMode); 
    }
    else if (ConstantPool.isProtected(access)) { 
        out.writeByte(protect); 
    }
    else /* if (ConstantPool.isPrivate(access)) */ { 
        out.writeByte(prvMode); 
    }
    if (name == null) {
        name = "DUMMY" + count++;
        System.err.println( name );
    }
    out.writeUTF(name);
  }

  static void writeString(DataOutputStream out,String str) throws IOException {
    out.writeByte(strSy);
    out.writeUTF(str);
  }

  static void writeLiteral(DataOutputStream out,Object val) throws IOException {
    if (val instanceof String) {
      writeString(out,(String) val);
    } else if (val instanceof Integer) {
      out.writeByte(numSy);
      out.writeLong(((Integer)val).longValue());
    } else if (val instanceof Long) {
      out.writeByte(numSy);
      out.writeLong(((Long)val));
    } else if (val instanceof Float) {
      out.writeByte(fltSy);
      out.writeDouble(((Float)val).doubleValue());
    } else if (val instanceof Double) {
      out.writeByte(fltSy);
      out.writeDouble(((Double)val));
    } else {
      System.out.println("Unknown constant type");
      System.exit(1);
    }
  }

  public static void writeOrd(DataOutputStream out,int i) throws IOException {
    // DIAGNOSTIC
    if (i < 0)
        throw new IOException(); 
    // DIAGNOSTIC
    if (i <= 0x7f) {
        out.writeByte(i);
    } else if (i <= 0x7fff) {
        out.writeByte(128 + i % 128);  
        out.writeByte(i / 128);
    } else {
        throw new IOException(); 
    }
  }

  private static void InsertTypeInTypeList(TypeDesc ty) {
    if (ty.outTypeNum > 0) { return; }
    ty.outTypeNum = nextType++;
    if (tListIx >= typeList.length) {
      TypeDesc[] tmp = new TypeDesc[typeList.length + initTypeListSize];
      System.arraycopy(typeList, 0, tmp, 0, typeList.length);
      typeList = tmp;
    }
    // Temporary diagnostic code
    if (ClassDesc.VERBOSE && (ty.name != null)) {
        System.out.printf("Inserting %s at ix %d\n", ty.name, tListIx);
        if (ty instanceof ClassDesc 
                && target != ((ClassDesc)ty).parentPkg
                && !imps.contains(((ClassDesc)ty).parentPkg)) {
            System.err.println(ty.name + " not on import list");
        }
    }
    typeList[tListIx++] = ty;
  }

  public static void AddTypeToTypeList(TypeDesc ty) {
    InsertTypeInTypeList(ty); 
    if (!ty.writeDetails) { 
        return; 
    }
    if (ty instanceof ClassDesc) {
        ClassDesc aClass = (ClassDesc)ty;
        if (aClass.outBaseTypeNum > 0) { 
            return; 
        }
        aClass.outBaseTypeNum = nextType++;
        if (aClass.superClass != null) {
            aClass.superClass.writeDetails = true; 
            AddTypeToTypeList(aClass.superClass); 
        }
        if (aClass.isInterface) {
            for (ClassDesc intf : aClass.interfaces) {
                intf.writeDetails = true;
                AddTypeToTypeList(intf); // Recurse
            }
        }
    } else if (ty instanceof PtrDesc) { 
        ty = ((PtrDesc)ty).boundType; 
        if (ty.outTypeNum == 0) { 
            AddTypeToTypeList(ty); 
        }
    } else if (ty instanceof ArrayDesc) {
        ty = ((ArrayDesc)ty).elemType;
        while (ty instanceof ArrayDesc) {
            ArrayDesc aTy = (ArrayDesc)ty;
            if (aTy.ptrType.outTypeNum == 0) { 
                InsertTypeInTypeList(aTy.ptrType); 
            }
            if (aTy.outTypeNum == 0) { 
                InsertTypeInTypeList(aTy); 
            }
            ty = aTy.elemType;
        }                   
        if (ty.outTypeNum == 0) { 
            InsertTypeInTypeList(ty); 
        }
    }
  }

    /**
     * Writes out the ordinal number of the type denoted by this
     * <code>TypeDesc</code> object. If a descriptor does not have
     * a ordinal already allocated this implies that the type has
     * not yet been added to the type-list. In this case the type
     * is added to the list and an ordinal allocated.
     * <p>
     * Builtin types have pre-allocated type ordinal, less than 
     * <code>TypeDesc.ordT</code>.
     * @param out The data stream to which the symbol file is being written.
     * @param ty The <code>TypeDesc</code> whose type ordinal is required.
     * @throws IOException 
     */
    static void writeTypeOrd(DataOutputStream out,TypeDesc ty)throws IOException {
        if (ty.typeOrd < TypeDesc.ordT) { 
            // ==> ty is a builtin type.
            out.writeByte(ty.typeOrd); 
        } else {
            if (ty.outTypeNum == 0) { 
              // ==> ty is a class type.
              AddTypeToTypeList(ty); // blame ty
            }
            if (ty.outTypeNum == 0) { 
                System.out.println("ERROR: type has number 0 for type " + ty.name); 
                System.exit(1); 
            }
            writeOrd(out,ty.outTypeNum);
        }
    }

  public static void WriteFormalType(MethodInfo m,DataOutputStream out) 
                                                     throws IOException {
    if ((m.retType != null) && (m.retType.typeOrd != 0)) {
      out.writeByte(retSy);
      writeTypeOrd(out,m.retType);
    } 
    out.writeByte(frmSy);
      for (TypeDesc parType : m.parTypes) {
          out.writeByte(parSy);
          if (parType instanceof ArrayDesc) {
              out.writeByte(1);   // array params are IN
          } else {
              out.writeByte(0);   // all other java parameters are value 
          }
          writeTypeOrd(out, parType);
      }
    out.writeByte(endFm);
  }

  public static void WriteSymbolFile(PackageDesc thisPack) throws IOException{
    ClearTypeList();
    DataOutputStream out = j2cpsfiles.CreateSymFile(thisPack.cpName);
    out.writeInt(magic);
    out.writeByte(modSy);
    writeName(out,0,thisPack.cpName);
    writeString(out,thisPack.javaName);
    out.writeByte(falSy); /* package is not an interface */
    // #############################
    imps = thisPack.pkgImports;
    target = thisPack;
    // #############################
    //
    //  Emit package import list
    //    Import = impSy Name [String] Key.
    //  Imports are given an index as they are listed.
    //
    for (int i=0; i < thisPack.pkgImports.size(); i++) {
        out.writeByte(impSy);
        PackageDesc imp = (PackageDesc)thisPack.pkgImports.get(i);
        // -------------------
        if (ClassDesc.VERBOSE)
            System.out.printf("import %d %s %d\n", 
                i, 
               (imp.javaName == null ? "null" : imp.javaName), 
                i+1);      
        // -------------------
        imp.impNum = i+1;
        writeName(out,0,imp.cpName);
        writeString(out,imp.javaName);
        out.writeByte(keySy);
        out.writeInt(0);
    }
    for (ClassDesc thisClass : thisPack.myClasses) {
        if ((thisClass != null) && ConstantPool.isPublic(thisClass.access)) {
            // -------------------
            if (ClassDesc.verbose)
                System.out.printf("Member class %s\n", thisClass.javaName);   
            // -------------------
            // This class is a class of the package being
            // emitted to this symbol file. Details are required.
            // -------------------
            thisClass.writeDetails = true;
            out.writeByte(typSy);
            writeName(out,thisClass.access,thisClass.objName);
            writeTypeOrd(out,thisClass);
        }
    }
    //
    //  Write out typelist
    //
    out.writeByte(start);
    for (int i=0; i < tListIx; i++) {
        TypeDesc desc = typeList[i];
        // -------------------
        if (ClassDesc.VERBOSE) 
            System.out.printf("typeList element %d (of %d) %s %d\n", 
                i, tListIx,
               (desc.name == null ? "null" : desc.name), 
                desc.outTypeNum); 
        // -------------------
        out.writeByte(tDefS);
        writeOrd(out,desc.outTypeNum);      
        desc.writeType(out, thisPack);
    }
    out.writeByte(close);
    out.writeByte(keySy);
    out.writeInt(0);
    thisPack.ResetImports();
  }

  //
  // Symbol file reading 
  //
  private static void InsertType(int tNum,TypeDesc ty) {
    if (tNum >= typeList.length) {
      int newLen = 2 * typeList.length;
      while (tNum >= newLen) { newLen += typeList.length; }
      TypeDesc[] tmp = new TypeDesc[newLen];
      System.arraycopy(typeList, 0, tmp, 0, typeList.length);
      typeList = tmp;
    }
    typeList[tNum] = ty;
  }


  private static int readOrd() throws IOException {
    int b1 = in.readUnsignedByte();
    if (b1 <= 0x7f) { return b1; }
    else { int b2 = in.readByte();
           return b1 - 128 + b2 * 128; }
  }

  private static void GetSym() throws IOException {
    sSym = in.readByte();
    switch (sSym) {
      case namSy : acc = in.readByte();         // fall through 
      case strSy : name = in.readUTF(); break;
      case arrSy :
      case ptrSy :
      case retSy : 
      case fromS : 
      case tDefS : 
      case basSy : tOrd = readOrd(); break;
      case bytSy : iVal = in.readByte(); break;
      case keySy : 
      case setSy : iVal = in.readInt(); break;
      case numSy : lVal = in.readLong(); break;
      case fltSy : dVal = in.readDouble(); break;
      case chrSy : cVal = in.readChar(); break;
      case modSy : 
      case impSy : 
      case conSy : 
      case varSy : 
      case typSy : 
      case prcSy : 
      case mthSy : 
      case parSy : 
      case start : 
      case close : 
      case falSy : 
      case truSy : 
      case frmSy : 
      case endFm : 
      case recSy : 
      case endRc : 
      case endAr : 
      case eTpSy :
      case iFcSy :
      case evtSy :
      case pTpSy : break;
      default:  char ch = (char) sSym;
                System.out.println("Bad symbol file format." +ch+"  "+sSym);
                System.exit(1);
    }
  }

  private static void Expect(int expSym) throws IOException {
    if (expSym != sSym) {
      System.out.println("Error in symbol file:  expecting " + 
      String.valueOf((char) expSym) + " got " +
      String.valueOf((char) sSym));
      System.exit(1);
    }
    GetSym();
  }

  private static void Check(int expSym) {
    if (expSym != sSym) {
      System.out.println("Error in symbol file:  checking " + 
      String.valueOf((char) expSym) + " got " +
      String.valueOf((char) sSym));
      System.exit(1);
    }
  }

  private static void SkipToEndRec(DataInputStream in) throws IOException {
    while (sSym != endRc) { 
        switch (sSym) {
            case mthSy:
                GetSym(); // name
                in.readByte();
                in.readByte();
                readOrd();
                break;
            case varSy:
                GetSym(); // name
                readOrd();
                break;
            case conSy:
                GetSym(); // name
                GetSym(); // Literal
                break;
            case prcSy:
                GetSym(); // name
                break;
            case parSy:
                in.readByte();
                readOrd();
                break;
            case namSy:
                readOrd();
                break;
            default:
                break;
        }
      GetSym(); 
    }
  }

  private static int GetAccess() {
      switch (acc) {
          case prvMode:
              return ConstantPool.ACC_PRIVATE;
          case pubMode:
              return ConstantPool.ACC_PUBLIC;
          case protect:
              return ConstantPool.ACC_PROTECTED;
          default:
              break;
      }
    return 0;
  }

  private static ClassDesc GetClassDesc(PackageDesc thisPack,String className) {
    ClassDesc aClass = ClassDesc.GetClassDesc(thisPack.name + Util.FWDSLSH + 
                                              className,thisPack);
    if (aClass.fieldList == null){ aClass.fieldList = new ArrayList<>(); }
    if (aClass.methodList == null){ aClass.methodList = new ArrayList<>(); }
    return aClass;
  }

  private static void GetConstant(ClassDesc cClass) throws IOException {
  // Constant = conSy Name Literal.
  // Literal  = Number | String | Set | Char | Real | falSy | truSy.
    TypeDesc typ = null;
    Object val = null;
    Expect(conSy);
    String constName = name; 
    int fAcc = GetAccess();
    fAcc = fAcc + ConstantPool.ACC_STATIC + ConstantPool.ACC_FINAL;
    Expect(namSy); 
    switch (sSym) {
      case numSy : typ = TypeDesc.GetBasicType(TypeDesc.longT); 
                   val = lVal; break;
      case strSy : typ = TypeDesc.GetBasicType(TypeDesc.strT);
                   val = name; break;
      case setSy : typ = TypeDesc.GetBasicType(TypeDesc.setT);
                   val = iVal; break;
      case chrSy : typ = TypeDesc.GetBasicType(TypeDesc.charT);
                   val = cVal; break;
      case fltSy : typ = TypeDesc.GetBasicType(TypeDesc.dbleT);
                   val = dVal; break;
      case falSy : typ = TypeDesc.GetBasicType(TypeDesc.boolT);
                   val = false; break;
      case truSy : typ = TypeDesc.GetBasicType(TypeDesc.boolT);
                   val = true; break;
    }
    boolean ok = cClass.fieldList.add(new FieldInfo(cClass,fAcc,constName,typ,val));
    GetSym();
  }

  private static void GetVar(ClassDesc vClass) throws IOException {
  // Variable = varSy Name TypeOrd.
    Expect(varSy);
    String varName = name; 
    int fAcc = GetAccess();
    Check(namSy);
    FieldInfo f = new FieldInfo(vClass,fAcc,varName,null,null);
    f.typeFixUp = readOrd();
    vClass.fieldList.add(f);
    GetSym();
  }

  private static void GetType(PackageDesc thisPack) throws IOException {
  // Type = typSy Name TypeOrd.
    Expect(typSy);
    ClassDesc thisClass = GetClassDesc(thisPack,name); 
    thisClass.access = GetAccess();
    Check(namSy);
    int tNum = readOrd();
    thisClass.inTypeNum = tNum;
    InsertType(tNum,thisClass);
    GetSym();
  }

  private static void GetFormalType(ClassDesc thisClass,MethodInfo thisMethod) 
                                                           throws IOException {
  // FormalType = [retSy TypeOrd] frmSy {parSy Byte TypeOrd} endFm.
    int [] pars = new int[20];
    int numPars = 0;
    TypeDesc retType = TypeDesc.GetBasicType(TypeDesc.noTyp);
    if (sSym == retSy) { thisMethod.retTypeFixUp = tOrd; GetSym();} 
    Expect(frmSy);
    while (sSym != endFm) {
      Check(parSy);
      in.readByte();   /* ignore par mode */
      pars[numPars++] = readOrd(); 
      GetSym();
    }  
    Expect(endFm);
    thisMethod.parFixUps = new int[numPars];
    System.arraycopy(pars, 0, thisMethod.parFixUps, 0, numPars);
  }


  private static void GetMethod(ClassDesc thisClass) throws IOException {
  // Method = mthSy Name Byte Byte TypeOrd [String] FormalType.
    String jName = null;
    Expect(mthSy);
    Check(namSy);
    String nam = name; 
    int pAcc = GetAccess();
    int attr = in.readByte();
    int recMode = in.readByte();  
    int cNum = readOrd();
    if (cNum != thisClass.inTypeNum) {
      System.err.println("Method not part of THIS class!");
      System.exit(1);
    }  
    GetSym();
    if (sSym == strSy) { jName = name; GetSym();  }
    MethodInfo m = new MethodInfo(thisClass,nam,jName,pAcc); 
    switch (attr) {
      case 1 : if (!m.isInitProc) {
                 m.accessFlags += ConstantPool.ACC_FINAL; 
               }
               break;
      case 2 : m.overridding = true;
               m.accessFlags += (ConstantPool.ACC_ABSTRACT + 
                                 ConstantPool.ACC_FINAL); 
               break;
      case 3 : m.accessFlags += (ConstantPool.ACC_ABSTRACT +
                                 ConstantPool.ACC_FINAL); 
               break;
      case 6 : m.overridding = true;
               break;
      case 7 : break; 
    }
    GetFormalType(thisClass,m);
    thisClass.methodList.add(m);
    thisClass.scope.put(m.name,m);
  }

  private static void GetProc(ClassDesc pClass) throws IOException {
  // Proc = prcSy Name [String] [truSy] FormalType.
    String jName = null;
    Expect(prcSy);
    String procName = name; 
    int pAcc = GetAccess();
    pAcc = pAcc + ConstantPool.ACC_STATIC;
    Expect(namSy); 
    if (sSym == strSy) { jName = name; GetSym();  }
    MethodInfo m = new MethodInfo(pClass,procName,jName,pAcc); 
    if (sSym == truSy) { 
        m.isInitProc = true; GetSym();  
    }
    GetFormalType(pClass,m);
    pClass.methodList.add(m);
  }

  private static void ClearTypeList() {
    for (int i=0; i < typeList.length; i++) {
      if (typeList[i] != null) {
        if (typeList[i].typeOrd >= TypeDesc.specT) {
          typeList[i].inTypeNum = 0; 
          typeList[i].outTypeNum = 0; 
        }
        if (typeList[i] instanceof ClassDesc) {
          ((ClassDesc)typeList[i]).inBaseTypeNum = 0;
          ((ClassDesc)typeList[i]).outBaseTypeNum = 0;
          ((ClassDesc)typeList[i]).writeDetails = false;
        } else if (typeList[i] instanceof ArrayDesc) {
          ((ArrayDesc)typeList[i]).elemTypeFixUp = 0;
        }
      }
      typeList[i] = null; 
    }
    tListIx = 0;
    nextType = TypeDesc.ordT;
  }

  private static void FixArrayElemType(ArrayDesc arr) {
    if (arr.elemTypeFixUp == 0) { return; }
    TypeDesc elem = GetFixUpType(arr.elemTypeFixUp);
    if (elem instanceof ArrayDesc) {
      FixArrayElemType((ArrayDesc)elem); 
      arr.dim = ((ArrayDesc)elem).dim + 1;
      arr.ultimateElemType = ((ArrayDesc)elem).ultimateElemType;
    } else {
      arr.ultimateElemType = elem;
    }
    arr.elemType = elem;
  }

  private static TypeDesc GetFixUpType (int num) {
    if (num < TypeDesc.specT) { return TypeDesc.GetBasicType(num); }
    if (typeList[num] instanceof PtrDesc) { 
      return ((PtrDesc)typeList[num]).boundType;
    }
    return typeList[num];
  } 

    public static void ReadSymbolFile(File symFile, PackageDesc thisPack)
            throws FileNotFoundException, IOException {
        if (ClassDesc.verbose) {
            System.out.println("INFO:  Reading symbol file " + symFile.getName());
        }

        ClearTypeList();
        ClassDesc aClass, impClass;
        int maxInNum = 0;
        //
        //  Read the symbol file and create descriptors
        //
        try (FileInputStream fIn = new FileInputStream(symFile)) {
            in = new DataInputStream(fIn);
            if (in.readInt() != magic) {
                System.out.println(symFile.getName() + " is not a valid symbol file.");
                System.exit(1);
            }
            GetSym();
            Expect(modSy);
            if (!thisPack.cpName.equals(name)) {
                System.out.println("ERROR:  Symbol file " + symFile.getName()
                        + " does not contain MODULE " + thisPack.cpName + ", it contains MODULE "
                        + name);
                System.exit(1);
            }
            Expect(namSy);
            if (sSym == strSy) {
                if (!name.equals(thisPack.javaName)) {
                    System.out.println("Wrong name in symbol file.");
                    System.exit(1);
                }
                GetSym();
                if (sSym == truSy) {
                    System.out.println("ERROR:  Java Package cannot be an interface.");
                    System.exit(1);
                }
                GetSym();
            } else {
                System.err.println("<" + symFile.getName()
                        + "> NOT A SYMBOL FILE FOR A JAVA PACKAGE!");
                System.exit(1);
            }
            while (sSym != start) {
                switch (sSym) {
                    case impSy:
                        GetSym(); // name
                        String iName = name;
                        GetSym();
                        if (sSym == strSy) {
                            PackageDesc pack = PackageDesc.getPackage(name);
                            thisPack.pkgImports.add(pack);
                            GetSym();
                        }
                        Expect(keySy);
                        break;
                    case conSy:
                    case varSy:
                    case prcSy:
                        System.out.println("Symbol File is not from a java class");
                        System.exit(1);
                        break;
                    case typSy:
                        GetType(thisPack);
                        break;
                }
            }
            Expect(start);
            while (sSym != close) {
                PackageDesc impPack;
                impClass = null;
                String impModName = null;
                int impAcc = 0,
                        impModAcc = 0;
                Check(tDefS);
                int tNum = tOrd;
                GetSym();
                if (tNum > maxInNum) {
                    maxInNum = tNum;
                }
                if (sSym == fromS) {
                    int impNum = tOrd - 1;
                    GetSym();
                    Check(namSy);
                    String impName = name;
                    impAcc = acc;
                    if (impNum < 0) {
                        impPack = thisPack;
                    } else {
                        impPack = (PackageDesc) thisPack.pkgImports.get(impNum);
                    }
                    impClass = GetClassDesc(impPack, impName);
                    GetSym();
                }
                switch (sSym) {
                    case arrSy:
                        ArrayDesc newArr;
                        int elemOrd = tOrd;
                        GetSym();
                        Expect(endAr);
                        TypeDesc eTy = null;
                        if (elemOrd < typeList.length) {
                            if (elemOrd < TypeDesc.specT) {
                                eTy = TypeDesc.GetBasicType(elemOrd);
                            } else {
                                eTy = typeList[elemOrd];
                            }
                            if ((eTy != null) && (eTy instanceof PtrDesc)
                                    && (((PtrDesc) eTy).boundType != null)
                                    && (((PtrDesc) eTy).boundType instanceof ClassDesc)) {
                                eTy = ((PtrDesc) eTy).boundType;
                            }
                        }
                        if (eTy != null) {
                            newArr = ArrayDesc.FindOrCreateArrayType(1, eTy, true);
                        } else {
                            newArr = new ArrayDesc(elemOrd);
                        }
                        if ((tNum < typeList.length) && (typeList[tNum] != null)) {
                            PtrDesc desc = (PtrDesc) typeList[tNum];
                            if (desc.inBaseTypeNum != tNum) {
                                System.out.println("WRONG BASE TYPE FOR POINTER!");
                                System.exit(1);
                            }
                            desc.Init(newArr);
                            newArr.SetPtrType(desc);
                        }
                        InsertType(tNum, newArr);
                        break;
                    case ptrSy:
                        TypeDesc ty;
                        if (impClass != null) {
                            InsertType(tNum, impClass);
                            ty = impClass;
                            ty.inTypeNum = tNum;
                            ty.inBaseTypeNum = tOrd;
                            InsertType(tOrd, ty);
                        } else if ((tNum < typeList.length)
                                && (typeList[tNum] != null)
                                && (typeList[tNum] instanceof ClassDesc)) {
                            ty = typeList[tNum];
                            ty.inTypeNum = tNum;
                            ty.inBaseTypeNum = tOrd;
                            InsertType(tOrd, ty);
                        } else {
                            ty = new PtrDesc(tNum, tOrd);
                            InsertType(tNum, ty);
                            if ((tOrd < typeList.length)
                                    && (typeList[tOrd] != null)) {
                                ((PtrDesc) ty).Init(typeList[tOrd]);
                            }
                        }
                        GetSym();
                        break;
                    case recSy:
                        if ((tNum >= typeList.length) 
                                || (typeList[tNum] == null)
                                || (!(typeList[tNum] instanceof ClassDesc))) {
                            /* cannot have record type that is not a base type
                               of a pointer in a java file                     */
                            System.err.println(
                                    "RECORD TYPE " + tNum + " IS NOT POINTER BASE TYPE!");
                            System.exit(1);
                        }
                        aClass = (ClassDesc) typeList[tNum];
                        acc = in.readByte();
                        aClass.setRecAtt(acc);
                        if (aClass.read) {
                            GetSym();
                            SkipToEndRec(in);
                            GetSym();
                        } else {
                            GetSym();
                            if (sSym == truSy) {
                                aClass.isInterface = true;
                                GetSym();
                            } else if (sSym == falSy) {
                                GetSym();
                            }
                            if (sSym == basSy) {
                                aClass.superNum = tOrd;
                                GetSym();
                            }
                            if (sSym == iFcSy) {
                                GetSym();
                                aClass.intNums = new int[10];
                                aClass.numInts = 0;
                                while (sSym == basSy) {
                                    if (aClass.numInts >= aClass.intNums.length) {
                                        int tmp[] = new int[aClass.intNums.length * 2];
                                        System.arraycopy(aClass.intNums, 0, tmp, 0, aClass.intNums.length);
                                        aClass.intNums = tmp;
                                    }
                                    aClass.intNums[aClass.numInts] = tOrd;
                                    aClass.numInts++;
                                    GetSym();
                                }
                            }
                            while (sSym == namSy) {
                                FieldInfo f = new FieldInfo(aClass, GetAccess(), name,
                                        null, null);
                                f.typeFixUp = readOrd();
                                GetSym();
                                boolean ok = aClass.fieldList.add(f);
                                aClass.scope.put(f.name, f);
                            }
                            while ((sSym == mthSy) || (sSym == prcSy)
                                    || (sSym == varSy) || (sSym == conSy)) {
                                switch (sSym) {
                                    case mthSy:
                                        GetMethod(aClass);
                                        break;
                                    case prcSy:
                                        GetProc(aClass);
                                        break;
                                    case varSy:
                                        GetVar(aClass);
                                        break;
                                    case conSy:
                                        GetConstant(aClass);
                                        break;
                                }
                            }
                            Expect(endRc);
                        }
                        break;
                    case pTpSy:
                        System.out.println("CANNOT HAVE PROC TYPE IN JAVA FILE!");
                        break;
                    case evtSy:
                        System.out.println("CANNOT HAVE EVENT TYPE IN JAVA FILE!");
                        break;
                    case eTpSy:
                        System.out.println("CANNOT HAVE ENUM TYPE IN JAVA FILE!");
                        break;
                    case tDefS:
                    case close:
                        InsertType(tNum, impClass);
                        break;
                    default:
                        char ch = (char) sSym;
                        System.out.println("UNRECOGNISED TYPE!" + sSym + "  " + ch);
                        System.exit(1);
                }
            }
            Expect(close);
            Check(keySy);
        }
        //
        //  Now do the type fixups
        //
        for (int i = TypeDesc.specT; i <= maxInNum; i++) {
            if ((typeList[i] != null) && (typeList[i] instanceof ClassDesc)) {
                if (!((ClassDesc) typeList[i]).read) {
                    aClass = (ClassDesc) typeList[i];
                    if (aClass.superNum != 0) {
                        aClass.superClass = (ClassDesc) typeList[aClass.superNum];
                    }
                    aClass.interfaces = new ClassDesc[aClass.numInts];
                    for (int j = 0; j < aClass.numInts; j++) {
                        aClass.interfaces[j] = (ClassDesc) GetFixUpType(aClass.intNums[j]);
                    }
                    int size;
                    if (aClass.fieldList == null) {
                        size = 0;
                    } else {
                        size = aClass.fieldList.size();
                    }
                    //aClass.fields = new FieldInfo[size];
                    for (int j = 0; j < size; j++) {
                        FieldInfo fieldJ = (FieldInfo) aClass.fieldList.get(j);
                        //aClass.fields[j] = fieldJ;
                        fieldJ.type = GetFixUpType(fieldJ.typeFixUp);
                        if (fieldJ.type instanceof ClassDesc) { // FIXME And is public?
                            aClass.AddImportToClass((ClassDesc) fieldJ.type);
                        }
                    }
                    aClass.fieldList = null;
                    if (aClass.methodList == null) {
                        size = 0;
                    } else {
                        size = aClass.methodList.size();
                    }
                    //aClass.methods = new MethodInfo[size];
                    for (int k = 0; k < size; k++) {
                        MethodInfo methodK = (MethodInfo) aClass.methodList.get(k);
                        //aClass.methods[k] = methodK;
                        methodK.retType = GetFixUpType(methodK.retTypeFixUp);
                        if (methodK.retType instanceof ClassDesc) {
                            aClass.AddImportToClass((ClassDesc) methodK.retType);
                        }
                        methodK.parTypes = new TypeDesc[methodK.parFixUps.length];
                        for (int j = 0; j < methodK.parFixUps.length; j++) {
                            methodK.parTypes[j] = GetFixUpType(methodK.parFixUps[j]);
                            if (methodK.parTypes[j] instanceof ClassDesc) {
                                aClass.AddImportToClass((ClassDesc) methodK.parTypes[j]);
                            }
                        }
                    }
                    aClass.methodList = null;
                    aClass.read = true;
                    aClass.done = true;
                }
            } else if ((typeList[i] != null) && (typeList[i] instanceof ArrayDesc)) {
                FixArrayElemType((ArrayDesc) typeList[i]);
            } else if ((typeList[i] != null) && (typeList[i] instanceof PtrDesc)) {
                PtrDesc ptr = (PtrDesc) typeList[i];
                if (ptr.typeOrd == TypeDesc.arrPtr) {
                    ptr.Init(typeList[ptr.inBaseTypeNum]);
                }
            } else if (typeList[i] != null) {
                System.out.println("Type " + i + " " + typeList[i].name
                        + " is NOT array or class");
                System.exit(0);
            }
        }
    }
}