/*
    *  Licensed to the Apache Software Foundation (ASF) under one or more
    *  contributor license agreements.  See the NOTICE file distributed with
    *  this work for additional information regarding copyright ownership.
    *  The ASF licenses this file to You under the Apache License, Version 2.0
    *  (the "License"); you may not use this file except in compliance with
    *  the License.  You may obtain a copy of the License at
    *
    *     http://www.apache.org/licenses/LICENSE-2.0
   *
   *  Unless required by applicable law or agreed to in writing, software
   *  distributed under the License is distributed on an "AS IS" BASIS,
   *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   *  See the License for the specific language governing permissions and
   *  limitations under the License.
   */
  package org.apache.commons.compress.harmony.unpack200.bytecode;
  
  import java.io.DataOutputStream;
  import java.io.IOException;
  import java.util.ArrayList;
  import java.util.List;
  
  import org.apache.commons.compress.harmony.unpack200.Segment;
  
  public class CodeAttribute extends BCIRenumberedAttribute {
  
      private static CPUTF8 attributeName;
  
      public static void setAttributeName(final CPUTF8 attributeName) {
          CodeAttribute.attributeName = attributeName;
      }
  
      public List<Attribute> attributes = new ArrayList<>();
      // instances
      public List<Integer> byteCodeOffsets = new ArrayList<>();
      public List<ByteCode> byteCodes = new ArrayList<>();
      public int codeLength;
      public List<ExceptionTableEntry> exceptionTable;
      public int maxLocals;
  
      public int maxStack;
  
      public CodeAttribute(final int maxStack, final int maxLocals, final byte[] codePacked, final Segment segment, final OperandManager operandManager,
              final List<ExceptionTableEntry> exceptionTable) {
          super(attributeName);
          this.maxLocals = maxLocals;
          this.maxStack = maxStack;
          this.codeLength = 0;
          this.exceptionTable = exceptionTable;
          byteCodeOffsets.add(Integer.valueOf(0));
          int byteCodeIndex = 0;
          for (int i = 0; i < codePacked.length; i++) {
              final ByteCode byteCode = ByteCode.getByteCode(codePacked[i] & 0xff);
              // Setting the offset must happen before extracting operands
              // because label bytecodes need to know their offsets.
              byteCode.setByteCodeIndex(byteCodeIndex);
              byteCodeIndex++;
              byteCode.extractOperands(operandManager, segment, codeLength);
              byteCodes.add(byteCode);
              codeLength += byteCode.getLength();
              final int lastBytecodePosition = byteCodeOffsets.get(byteCodeOffsets.size() - 1).intValue();
              // This code assumes all multiple byte bytecodes are
              // replaced by a single-byte bytecode followed by
              // another bytecode.
              if (byteCode.hasMultipleByteCodes()) {
                  byteCodeOffsets.add(Integer.valueOf(lastBytecodePosition + 1));
                  byteCodeIndex++;
              }
              // I've already added the first element (at 0) before
              // entering this loop, so make sure I don't add one
              // after the last element.
              if (i < codePacked.length - 1) {
                  byteCodeOffsets.add(Integer.valueOf(lastBytecodePosition + byteCode.getLength()));
              }
              if (byteCode.getOpcode() == 0xC4) {
                  // Special processing for wide bytecode - it knows what its
                  // instruction is from the opcode manager, so ignore the
                  // next instruction
                  i++;
              }
          }
          // Now that all the bytecodes know their positions and
          // sizes, fix up the byte code targets
          // At this point, byteCodes may be a different size than
          // codePacked because of wide bytecodes.
          for (final ByteCode byteCode : byteCodes) {
              byteCode.applyByteCodeTargetFixup(this);
          }
      }
  
      public void addAttribute(final Attribute attribute) {
          attributes.add(attribute);
          if (attribute instanceof LocalVariableTableAttribute) {
              ((LocalVariableTableAttribute) attribute).setCodeLength(codeLength);
          }
          if (attribute instanceof LocalVariableTypeTableAttribute) {
              ((LocalVariableTypeTableAttribute) attribute).setCodeLength(codeLength);
          }
     }
 
     @Override
     protected int getLength() {
         int attributesSize = 0;
         for (final Attribute attribute : attributes) {
             attributesSize += attribute.getLengthIncludingHeader();
         }
         return 2 + 2 + 4 + codeLength + 2 + exceptionTable.size() * (2 + 2 + 2 + 2) + 2 + attributesSize;
     }
 
     @Override
     protected ClassFileEntry[] getNestedClassFileEntries() {
         final List<ClassFileEntry> nestedEntries = new ArrayList<>(attributes.size() + byteCodes.size() + 10);
         nestedEntries.add(getAttributeName());
         nestedEntries.addAll(byteCodes);
         nestedEntries.addAll(attributes);
         // Don't forget to add the ExceptionTable catch_types
         for (final ExceptionTableEntry entry : exceptionTable) {
             final CPClass catchType = entry.getCatchType();
             // If the catch type is null, this is a finally
             // block. If it's not null, we need to add the
             // CPClass to the list of nested class file entries.
             if (catchType != null) {
                 nestedEntries.add(catchType);
             }
         }
         return nestedEntries.toArray(ClassFileEntry.NONE);
     }
 
     @Override
     protected int[] getStartPCs() {
         // Do nothing here as we've overriden renumber
         return null;
     }
 
     @Override
     public void renumber(final List<Integer> byteCodeOffsets) {
         exceptionTable.forEach(entry -> entry.renumber(byteCodeOffsets));
     }
 
     @Override
     protected void resolve(final ClassConstantPool pool) {
         super.resolve(pool);
         attributes.forEach(attribute -> attribute.resolve(pool));
         byteCodes.forEach(byteCode -> byteCode.resolve(pool));
         exceptionTable.forEach(byteCode -> byteCode.resolve(pool));
     }
 
     @Override
     public String toString() {
         return "Code: " + getLength() + " bytes";
     }
 
     @Override
     protected void writeBody(final DataOutputStream dos) throws IOException {
         dos.writeShort(maxStack);
         dos.writeShort(maxLocals);
 
         dos.writeInt(codeLength);
         for (final ByteCode byteCode : byteCodes) {
             byteCode.write(dos);
         }
 
         dos.writeShort(exceptionTable.size());
         for (final ExceptionTableEntry entry : exceptionTable) {
             entry.write(dos);
         }
 
         dos.writeShort(attributes.size());
         for (final Attribute attribute : attributes) {
             attribute.write(dos);
         }
     }
 }