/*
    * MIT License
    * Copyright (c) 2006-2025 JMockit developers
    * See LICENSE file for full license text.
    */
   package mockit.asm.fields;
   
   import edu.umd.cs.findbugs.annotations.NonNull;
   import edu.umd.cs.findbugs.annotations.Nullable;
  
  import mockit.asm.AnnotatedReader;
  import mockit.asm.classes.ClassReader;
  import mockit.asm.classes.ClassVisitor;
  
  import org.checkerframework.checker.index.qual.NonNegative;
  
  public final class FieldReader extends AnnotatedReader {
      @NonNull
      private final ClassVisitor cv;
      @Nullable
      private Object constantValue;
  
      public FieldReader(@NonNull ClassReader cr, @NonNull ClassVisitor cv) {
          super(cr);
          this.cv = cv;
      }
  
      /**
       * Reads each field and makes the given visitor visit it.
       *
       * @return the offset of the first byte following the last field in the class.
       */
      @NonNegative
      public int readFields() {
          for (int fieldCount = readUnsignedShort(); fieldCount > 0; fieldCount--) {
              readField();
          }
  
          return codeIndex;
      }
  
      private void readField() {
          access = readUnsignedShort();
          String name = readNonnullUTF8();
          String desc = readNonnullUTF8();
          constantValue = null;
  
          readAttributes();
  
          FieldVisitor fv = cv.visitField(access, name, desc, signature, constantValue);
  
          if (fv != null) {
              readAnnotations(fv);
              fv.visitEnd();
          }
      }
  
      @Nullable
      @Override
      protected Boolean readAttribute(@NonNull String attributeName) {
          if ("ConstantValue".equals(attributeName)) {
              int constItemIndex = readUnsignedShort();
  
              if (constItemIndex > 0) {
                  constantValue = readConst(constItemIndex);
              }
  
              return true;
          }
  
          return null;
      }
  }