/*
    *  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.pack200;
  
  import java.io.IOException;
  import java.io.OutputStream;
  
  /**
   * SegmentHeader is the header band of a {@link Segment}. Corresponds to {@code segment_header} in the pack200 specification.
   */
  public class SegmentHeader extends BandSet {
  
      /**
       * Counter for major/minor class file numbers, so we can work out the default
       */
      private static final class Counter {
  
          private final int[] objs = new int[8];
          private final int[] counts = new int[8];
          private int length;
  
          public void add(final int obj) {
              boolean found = false;
              for (int i = 0; i < length; i++) {
                  if (objs[i] == obj) {
                      counts[i]++;
                      found = true;
                  }
              }
              if (!found) {
                  objs[length] = obj;
                  counts[length] = 1;
                  length++;
                  if (length > objs.length - 1) {
                      final Object[] newArray = new Object[objs.length + 8];
                      System.arraycopy(objs, 0, newArray, 0, length);
                  }
              }
          }
  
          public int getMostCommon() {
              int returnIndex = 0;
              for (int i = 0; i < length; i++) {
                  if (counts[i] > counts[returnIndex]) {
                      returnIndex = i;
                  }
              }
              return objs[returnIndex];
          }
      }
  
      private static final int[] magic = { 0xCA, 0xFE, 0xD0, 0x0D };
      private static final int archive_minver = 7;
      private static final int archive_majver = 150;
  
      private int archive_options;
  
      private int cp_Utf8_count;
      private int cp_Int_count;
      private int cp_Float_count;
      private int cp_Long_count;
      private int cp_Double_count;
      private int cp_String_count;
      private int cp_Class_count;
      private int cp_Signature_count;
      private int cp_Descr_count;
      private int cp_Field_count;
      private int cp_Method_count;
      private int cp_Imethod_count;
  
      private int attribute_definition_count;
      private final IntList band_headers = new IntList();
  
      private boolean have_all_code_flags = true; // true by default
  
      private int archive_size_hi;
      private int archive_size_lo;
      private int archive_next_count;
      private int archive_modtime;
      private int file_count;
  
      private boolean deflate_hint;
      private final boolean have_file_modtime = true;
      private final boolean have_file_options = true;
      private boolean have_file_size_hi;
     private boolean have_class_flags_hi;
     private boolean have_field_flags_hi;
     private boolean have_method_flags_hi;
     private boolean have_code_flags_hi;
 
     private int ic_count;
     private int class_count;
     private final Counter majverCounter = new Counter();
 
     /**
      * Constructs a new SegmentHeader
      */
     public SegmentHeader() {
         super(1, null); // Pass 1 for effort because bands in the segment header
                         // should always use the default encoding
     }
 
     public void addMajorVersion(final int major) {
         majverCounter.add(major);
     }
 
     public void appendBandCodingSpecifier(final int specifier) {
         band_headers.add(specifier);
     }
 
     private void calculateArchiveOptions() {
         if (attribute_definition_count > 0 || band_headers.size() > 0) {
             archive_options |= 1;
         }
         if (cp_Int_count > 0 || cp_Float_count > 0 || cp_Long_count > 0 || cp_Double_count > 0) {
             archive_options |= 1 << 1;
         }
         if (have_all_code_flags) {
             archive_options |= 1 << 2;
         }
         if (file_count > 0) {
             archive_options |= 1 << 4;
         }
         if (deflate_hint) {
             archive_options |= 1 << 5;
         }
         if (have_file_modtime) {
             archive_options |= 1 << 6;
         }
         if (have_file_options) {
             archive_options |= 1 << 7;
         }
         if (have_file_size_hi) {
             archive_options |= 1 << 8;
         }
         if (have_class_flags_hi) {
             archive_options |= 1 << 9;
         }
         if (have_field_flags_hi) {
             archive_options |= 1 << 10;
         }
         if (have_method_flags_hi) {
             archive_options |= 1 << 11;
         }
         if (have_code_flags_hi) {
             archive_options |= 1 << 12;
         }
     }
 
     public int getArchive_modtime() {
         return archive_modtime;
     }
 
     public int getDefaultMajorVersion() {
         return majverCounter.getMostCommon();
     }
 
     public boolean have_all_code_flags() {
         return have_all_code_flags;
     }
 
     public boolean have_class_flags_hi() {
         return have_class_flags_hi;
     }
 
     public boolean have_code_flags_hi() {
         return have_code_flags_hi;
     }
 
     public boolean have_field_flags_hi() {
         return have_field_flags_hi;
     }
 
     public boolean have_file_modtime() {
         return have_file_modtime;
     }
 
     public boolean have_file_options() {
         return have_file_options;
     }
 
     public boolean have_file_size_hi() {
         return have_file_size_hi;
     }
 
     public boolean have_method_flags_hi() {
         return have_method_flags_hi;
     }
 
     /**
      * Encode and write the SegmentHeader bands to the OutputStream
      */
     @Override
     public void pack(final OutputStream out) throws IOException, Pack200Exception {
         out.write(encodeScalar(magic, Codec.BYTE1));
         out.write(encodeScalar(archive_minver, Codec.UNSIGNED5));
         out.write(encodeScalar(archive_majver, Codec.UNSIGNED5));
         calculateArchiveOptions();
         out.write(encodeScalar(archive_options, Codec.UNSIGNED5));
         writeArchiveFileCounts(out);
         writeArchiveSpecialCounts(out);
         writeCpCounts(out);
         writeClassCounts(out);
         if (band_headers.size() > 0) {
             out.write(encodeScalar(band_headers.toArray(), Codec.BYTE1));
         }
     }
 
     public void setAttribute_definition_count(final int attribute_definition_count) {
         this.attribute_definition_count = attribute_definition_count;
     }
 
     public void setClass_count(final int class_count) {
         this.class_count = class_count;
     }
 
     public void setCp_Class_count(final int count) {
         cp_Class_count = count;
     }
 
     public void setCp_Descr_count(final int count) {
         cp_Descr_count = count;
     }
 
     public void setCp_Double_count(final int count) {
         cp_Double_count = count;
     }
 
     public void setCp_Field_count(final int count) {
         cp_Field_count = count;
     }
 
     public void setCp_Float_count(final int count) {
         cp_Float_count = count;
     }
 
     public void setCp_Imethod_count(final int count) {
         cp_Imethod_count = count;
     }
 
     public void setCp_Int_count(final int count) {
         cp_Int_count = count;
     }
 
     public void setCp_Long_count(final int count) {
         cp_Long_count = count;
     }
 
     public void setCp_Method_count(final int count) {
         cp_Method_count = count;
     }
 
     public void setCp_Signature_count(final int count) {
         cp_Signature_count = count;
     }
 
     public void setCp_String_count(final int count) {
         cp_String_count = count;
     }
 
     public void setCp_Utf8_count(final int count) {
         cp_Utf8_count = count;
     }
 
     public void setDeflate_hint(final boolean deflate_hint) {
         this.deflate_hint = deflate_hint;
     }
 
     public void setFile_count(final int file_count) {
         this.file_count = file_count;
     }
 
     public void setHave_all_code_flags(final boolean have_all_code_flags) {
         this.have_all_code_flags = have_all_code_flags;
     }
 
     public void setHave_class_flags_hi(final boolean have_class_flags_hi) {
         this.have_class_flags_hi = have_class_flags_hi;
     }
 
     public void setHave_code_flags_hi(final boolean have_code_flags_hi) {
         this.have_code_flags_hi = have_code_flags_hi;
     }
 
     public void setHave_field_flags_hi(final boolean have_field_flags_hi) {
         this.have_field_flags_hi = have_field_flags_hi;
     }
 
     public void setHave_method_flags_hi(final boolean have_method_flags_hi) {
         this.have_method_flags_hi = have_method_flags_hi;
     }
 
     public void setIc_count(final int ic_count) {
         this.ic_count = ic_count;
     }
 
     private void writeArchiveFileCounts(final OutputStream out) throws IOException, Pack200Exception {
         if ((archive_options & 1 << 4) > 0) { // have_file_headers
             out.write(encodeScalar(archive_size_hi, Codec.UNSIGNED5));
             out.write(encodeScalar(archive_size_lo, Codec.UNSIGNED5));
             out.write(encodeScalar(archive_next_count, Codec.UNSIGNED5));
             out.write(encodeScalar(archive_modtime, Codec.UNSIGNED5));
             out.write(encodeScalar(file_count, Codec.UNSIGNED5));
         }
     }
 
     private void writeArchiveSpecialCounts(final OutputStream out) throws IOException, Pack200Exception {
         if ((archive_options & 1) > 0) { // have_special_formats
             out.write(encodeScalar(band_headers.size(), Codec.UNSIGNED5));
             out.write(encodeScalar(attribute_definition_count, Codec.UNSIGNED5));
         }
     }
 
     private void writeClassCounts(final OutputStream out) throws IOException, Pack200Exception {
         final int default_class_minver = 0;
         final int default_class_majver = majverCounter.getMostCommon();
         out.write(encodeScalar(ic_count, Codec.UNSIGNED5));
         out.write(encodeScalar(default_class_minver, Codec.UNSIGNED5));
         out.write(encodeScalar(default_class_majver, Codec.UNSIGNED5));
         out.write(encodeScalar(class_count, Codec.UNSIGNED5));
     }
 
     private void writeCpCounts(final OutputStream out) throws IOException, Pack200Exception {
         out.write(encodeScalar(cp_Utf8_count, Codec.UNSIGNED5));
         if ((archive_options & 1 << 1) != 0) { // have_cp_numbers
             out.write(encodeScalar(cp_Int_count, Codec.UNSIGNED5));
             out.write(encodeScalar(cp_Float_count, Codec.UNSIGNED5));
             out.write(encodeScalar(cp_Long_count, Codec.UNSIGNED5));
             out.write(encodeScalar(cp_Double_count, Codec.UNSIGNED5));
         }
         out.write(encodeScalar(cp_String_count, Codec.UNSIGNED5));
         out.write(encodeScalar(cp_Class_count, Codec.UNSIGNED5));
         out.write(encodeScalar(cp_Signature_count, Codec.UNSIGNED5));
         out.write(encodeScalar(cp_Descr_count, Codec.UNSIGNED5));
         out.write(encodeScalar(cp_Field_count, Codec.UNSIGNED5));
         out.write(encodeScalar(cp_Method_count, Codec.UNSIGNED5));
         out.write(encodeScalar(cp_Imethod_count, Codec.UNSIGNED5));
     }
 
 }