/*
    *  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;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.util.Arrays;
  
  import org.apache.commons.compress.harmony.pack200.BHSDCodec;
  import org.apache.commons.compress.harmony.pack200.Codec;
  import org.apache.commons.compress.harmony.pack200.CodecEncoding;
  import org.apache.commons.compress.harmony.pack200.Pack200Exception;
  import org.apache.commons.compress.harmony.pack200.PopulationCodec;
  import org.apache.commons.compress.harmony.unpack200.bytecode.CPClass;
  import org.apache.commons.compress.harmony.unpack200.bytecode.CPDouble;
  import org.apache.commons.compress.harmony.unpack200.bytecode.CPFieldRef;
  import org.apache.commons.compress.harmony.unpack200.bytecode.CPFloat;
  import org.apache.commons.compress.harmony.unpack200.bytecode.CPInteger;
  import org.apache.commons.compress.harmony.unpack200.bytecode.CPInterfaceMethodRef;
  import org.apache.commons.compress.harmony.unpack200.bytecode.CPLong;
  import org.apache.commons.compress.harmony.unpack200.bytecode.CPMethodRef;
  import org.apache.commons.compress.harmony.unpack200.bytecode.CPNameAndType;
  import org.apache.commons.compress.harmony.unpack200.bytecode.CPString;
  import org.apache.commons.compress.harmony.unpack200.bytecode.CPUTF8;
  import org.apache.commons.compress.utils.ExactMath;
  
  /**
   * Abstract superclass for a set of bands.
   */
  public abstract class BandSet {
  
      protected Segment segment;
  
      protected SegmentHeader header;
  
      public BandSet(final Segment segment) {
          this.segment = segment;
          this.header = segment.getSegmentHeader();
      }
  
      /**
       * Decodes a band and return an array of {@code int} values.
       *
       * @param name  the name of the band (primarily for logging/debugging purposes)
       * @param in    the InputStream to decode from
       * @param codec the default Codec for this band
       * @param count the number of elements to read
       * @return an array of decoded {@code int} values
       * @throws IOException      if there is a problem reading from the underlying input stream
       * @throws Pack200Exception if there is a problem decoding the value or that the value is invalid
       */
      public int[] decodeBandInt(final String name, final InputStream in, final BHSDCodec codec, final int count) throws IOException, Pack200Exception {
          if (count < 0) {
              throw new Pack200Exception("count < 0");
          }
          // Useful for debugging
  //        if (count > 0) {
  //            System.out.println("decoding " + name + " " + count);
  //        }
          Codec codecUsed = codec;
          if (codec.getB() == 1 || count == 0) {
              return codec.decodeInts(count, in);
          }
          final int[] getFirst = codec.decodeInts(1, in);
          if (getFirst.length == 0) {
              return getFirst;
          }
          final int first = getFirst[0];
          int[] band;
          if (codec.isSigned() && first >= -256 && first <= -1) {
              // Non-default codec should be used
              codecUsed = CodecEncoding.getCodec(-1 - first, header.getBandHeadersInputStream(), codec);
              band = codecUsed.decodeInts(count, in);
          } else if (!codec.isSigned() && first >= codec.getL() && first <= codec.getL() + 255) {
              // Non-default codec should be used
              codecUsed = CodecEncoding.getCodec(first - codec.getL(), header.getBandHeadersInputStream(), codec);
              band = codecUsed.decodeInts(count, in);
          } else {
              // First element should not be discarded
              band = codec.decodeInts(count - 1, in, first);
          }
          // Useful for debugging -E options:
          // if (!codecUsed.equals(codec)) {
          // int bytes = codecUsed.lastBandLength;
          // System.out.println(count + " " + name + " encoded with " + codecUsed + " " + bytes);
         // }
         if (codecUsed instanceof PopulationCodec) {
             final PopulationCodec popCodec = (PopulationCodec) codecUsed;
             final int[] favoured = popCodec.getFavoured().clone();
             Arrays.sort(favoured);
             for (int i = 0; i < band.length; i++) {
                 final boolean favouredValue = Arrays.binarySearch(favoured, band[i]) > -1;
                 final Codec theCodec = favouredValue ? popCodec.getFavouredCodec() : popCodec.getUnfavouredCodec();
                 if (theCodec instanceof BHSDCodec && ((BHSDCodec) theCodec).isDelta()) {
                     final BHSDCodec bhsd = (BHSDCodec) theCodec;
                     final long cardinality = bhsd.cardinality();
                     while (band[i] > bhsd.largest()) {
                         band[i] -= cardinality;
                     }
                     while (band[i] < bhsd.smallest()) {
                         band[i] = ExactMath.add(band[i], cardinality);
                     }
                 }
             }
         }
         return band;
     }
 
     /**
      * Decodes a band and return an array of {@code int[]} values.
      *
      * @param name         the name of the band (primarily for logging/debugging purposes)
      * @param in           the InputStream to decode from
      * @param defaultCodec the default codec for this band
      * @param counts       the numbers of elements to read for each int array within the array to be returned
      * @return an array of decoded {@code int[]} values
      * @throws IOException      if there is a problem reading from the underlying input stream
      * @throws Pack200Exception if there is a problem decoding the value or that the value is invalid
      */
     public int[][] decodeBandInt(final String name, final InputStream in, final BHSDCodec defaultCodec, final int[] counts)
             throws IOException, Pack200Exception {
         final int[][] result = new int[counts.length][];
         int totalCount = 0;
         for (final int count : counts) {
             totalCount += count;
         }
         final int[] twoDResult = decodeBandInt(name, in, defaultCodec, totalCount);
         int index = 0;
         for (int i = 0; i < result.length; i++) {
             if (counts[i] > twoDResult.length) {
                 throw new IOException("Counts value exceeds length of twoDResult");
             }
             result[i] = new int[counts[i]];
             for (int j = 0; j < result[i].length; j++) {
                 result[i][j] = twoDResult[index];
                 index++;
             }
         }
         return result;
     }
 
     protected String[] getReferences(final int[] ints, final String[] reference) {
         final String[] result = new String[ints.length];
         Arrays.setAll(result, i -> reference[ints[i]]);
         return result;
     }
 
     protected String[][] getReferences(final int[][] ints, final String[] reference) {
         final String[][] result = new String[ints.length][];
         for (int i = 0; i < result.length; i++) {
             result[i] = new String[ints[i].length];
             for (int j = 0; j < result[i].length; j++) {
                 result[i][j] = reference[ints[i][j]];
             }
         }
         return result;
     }
 
     public CPClass[] parseCPClassReferences(final String name, final InputStream in, final BHSDCodec codec, final int count)
             throws IOException, Pack200Exception {
         final int[] indices = decodeBandInt(name, in, codec, count);
         final CPClass[] result = new CPClass[indices.length];
         for (int i1 = 0; i1 < count; i1++) {
             result[i1] = segment.getCpBands().cpClassValue(indices[i1]);
         }
         return result;
     }
 
     public CPNameAndType[] parseCPDescriptorReferences(final String name, final InputStream in, final BHSDCodec codec, final int count)
             throws IOException, Pack200Exception {
         final CpBands cpBands = segment.getCpBands();
         final int[] indices = decodeBandInt(name, in, codec, count);
         final CPNameAndType[] result = new CPNameAndType[indices.length];
         for (int i1 = 0; i1 < count; i1++) {
             final int index = indices[i1];
             result[i1] = cpBands.cpNameAndTypeValue(index);
         }
         return result;
     }
 
     public CPDouble[] parseCPDoubleReferences(final String name, final InputStream in, final BHSDCodec codec, final int count)
             throws IOException, Pack200Exception {
         final int[] indices = decodeBandInt(name, in, codec, count);
         final CPDouble[] result = new CPDouble[indices.length];
         for (int i1 = 0; i1 < count; i1++) {
             result[i1] = segment.getCpBands().cpDoubleValue(indices[i1]);
         }
         return result;
     }
 
     public CPFieldRef[] parseCPFieldRefReferences(final String name, final InputStream in, final BHSDCodec codec, final int count)
             throws IOException, Pack200Exception {
         final CpBands cpBands = segment.getCpBands();
         final int[] indices = decodeBandInt(name, in, codec, count);
         final CPFieldRef[] result = new CPFieldRef[indices.length];
         for (int i1 = 0; i1 < count; i1++) {
             final int index = indices[i1];
             result[i1] = cpBands.cpFieldValue(index);
         }
         return result;
     }
 
     public CPFloat[] parseCPFloatReferences(final String name, final InputStream in, final BHSDCodec codec, final int count)
             throws IOException, Pack200Exception {
         final int[] indices = decodeBandInt(name, in, codec, count);
         final CPFloat[] result = new CPFloat[indices.length];
         for (int i1 = 0; i1 < count; i1++) {
             result[i1] = segment.getCpBands().cpFloatValue(indices[i1]);
         }
         return result;
     }
 
     public CPInterfaceMethodRef[] parseCPInterfaceMethodRefReferences(final String name, final InputStream in, final BHSDCodec codec, final int count)
             throws IOException, Pack200Exception {
         final CpBands cpBands = segment.getCpBands();
         final int[] indices = decodeBandInt(name, in, codec, count);
         final CPInterfaceMethodRef[] result = new CPInterfaceMethodRef[indices.length];
         for (int i1 = 0; i1 < count; i1++) {
             result[i1] = cpBands.cpIMethodValue(indices[i1]);
         }
         return result;
     }
 
     public CPInteger[] parseCPIntReferences(final String name, final InputStream in, final BHSDCodec codec, final int count)
             throws IOException, Pack200Exception {
         final int[] reference = segment.getCpBands().getCpInt();
         final int[] indices = decodeBandInt(name, in, codec, count);
         final CPInteger[] result = new CPInteger[indices.length];
         for (int i1 = 0; i1 < count; i1++) {
             final int index = indices[i1];
             if (index < 0 || index >= reference.length) {
                 throw new Pack200Exception("Something has gone wrong during parsing references, index = " + index + ", array size = " + reference.length);
             }
             result[i1] = segment.getCpBands().cpIntegerValue(index);
         }
         return result;
     }
 
     public CPLong[] parseCPLongReferences(final String name, final InputStream in, final BHSDCodec codec, final int count)
             throws IOException, Pack200Exception {
         final long[] reference = segment.getCpBands().getCpLong();
         final int[] indices = decodeBandInt(name, in, codec, count);
         final CPLong[] result = new CPLong[indices.length];
         for (int i1 = 0; i1 < count; i1++) {
             final int index = indices[i1];
             if (index < 0 || index >= reference.length) {
                 throw new Pack200Exception("Something has gone wrong during parsing references, index = " + index + ", array size = " + reference.length);
             }
             result[i1] = segment.getCpBands().cpLongValue(index);
         }
         return result;
     }
 
     public CPMethodRef[] parseCPMethodRefReferences(final String name, final InputStream in, final BHSDCodec codec, final int count)
             throws IOException, Pack200Exception {
         final CpBands cpBands = segment.getCpBands();
         final int[] indices = decodeBandInt(name, in, codec, count);
         final CPMethodRef[] result = new CPMethodRef[indices.length];
         for (int i1 = 0; i1 < count; i1++) {
             result[i1] = cpBands.cpMethodValue(indices[i1]);
         }
         return result;
     }
 
     public CPUTF8[] parseCPSignatureReferences(final String name, final InputStream in, final BHSDCodec codec, final int count)
             throws IOException, Pack200Exception {
         final int[] indices = decodeBandInt(name, in, codec, count);
         final CPUTF8[] result = new CPUTF8[indices.length];
         for (int i1 = 0; i1 < count; i1++) {
             result[i1] = segment.getCpBands().cpSignatureValue(indices[i1]);
         }
         return result;
     }
 
     protected CPUTF8[][] parseCPSignatureReferences(final String name, final InputStream in, final BHSDCodec codec, final int[] counts)
             throws IOException, Pack200Exception {
         int sum = 0;
         for (int i = 0; i < counts.length; i++) {
             sum += counts[i];
         }
         final int[] indices = decodeBandInt(name, in, codec, sum);
         final CPUTF8[] result1 = new CPUTF8[sum];
         for (int i1 = 0; i1 < sum; i1++) {
             result1[i1] = segment.getCpBands().cpSignatureValue(indices[i1]);
         }
         int pos = 0;
         final CPUTF8[][] result = new CPUTF8[counts.length][];
         for (int i = 0; i < counts.length; i++) {
             final int num = counts[i];
             result[i] = new CPUTF8[num];
             System.arraycopy(result1, pos, result[i], 0, num);
             pos += num;
         }
         return result;
     }
 
     public CPString[] parseCPStringReferences(final String name, final InputStream in, final BHSDCodec codec, final int count)
             throws IOException, Pack200Exception {
         final int[] indices = decodeBandInt(name, in, codec, count);
         final CPString[] result = new CPString[indices.length];
         for (int i1 = 0; i1 < count; i1++) {
             result[i1] = segment.getCpBands().cpStringValue(indices[i1]);
         }
         return result;
     }
 
     public CPUTF8[] parseCPUTF8References(final String name, final InputStream in, final BHSDCodec codec, final int count)
             throws IOException, Pack200Exception {
         final int[] indices = decodeBandInt(name, in, codec, count);
         final CPUTF8[] result = new CPUTF8[indices.length];
         for (int i1 = 0; i1 < count; i1++) {
             final int index = indices[i1];
             result[i1] = segment.getCpBands().cpUTF8Value(index);
         }
         return result;
     }
 
     public CPUTF8[][] parseCPUTF8References(final String name, final InputStream in, final BHSDCodec codec, final int[] counts)
             throws IOException, Pack200Exception {
         final CPUTF8[][] result = new CPUTF8[counts.length][];
         int sum = 0;
         for (int i = 0; i < counts.length; i++) {
             result[i] = new CPUTF8[counts[i]];
             sum += counts[i];
         }
         final CPUTF8[] result1 = new CPUTF8[sum];
         final int[] indices = decodeBandInt(name, in, codec, sum);
         for (int i1 = 0; i1 < sum; i1++) {
             final int index = indices[i1];
             result1[i1] = segment.getCpBands().cpUTF8Value(index);
         }
         int pos = 0;
         for (int i = 0; i < counts.length; i++) {
             final int num = counts[i];
             result[i] = new CPUTF8[num];
             System.arraycopy(result1, pos, result[i], 0, num);
             pos += num;
         }
         return result;
     }
 
     public long[] parseFlags(final String name, final InputStream in, final int count, final BHSDCodec hiCodec, final BHSDCodec loCodec)
             throws IOException, Pack200Exception {
         return parseFlags(name, in, new int[] { count }, hiCodec, loCodec)[0];
     }
 
     public long[] parseFlags(final String name, final InputStream in, final int count, final BHSDCodec codec, final boolean hasHi)
             throws IOException, Pack200Exception {
         return parseFlags(name, in, new int[] { count }, hasHi ? codec : null, codec)[0];
     }
 
     public long[][] parseFlags(final String name, final InputStream in, final int[] counts, final BHSDCodec hiCodec, final BHSDCodec loCodec)
             throws IOException, Pack200Exception {
         final int count = counts.length;
         if (count == 0) {
             return new long[][] { {} };
         }
         int sum = 0;
         final long[][] result = new long[count][];
         for (int i = 0; i < count; i++) {
             sum += counts[i];
         }
         int[] hi = null;
         int[] lo;
         if (hiCodec != null) {
             hi = decodeBandInt(name, in, hiCodec, sum);
         }
         lo = decodeBandInt(name, in, loCodec, sum);
 
         int index = 0;
         for (int i = 0; i < count; i++) {
             result[i] = new long[counts[i]];
             for (int j = 0; j < result[i].length; j++) {
                 if (hi != null) {
                     result[i][j] = (long) hi[index] << 32 | lo[index] & 4294967295L;
                 } else {
                     result[i][j] = lo[index];
                 }
                 index++;
             }
         }
         return result;
     }
 
     public long[][] parseFlags(final String name, final InputStream in, final int[] counts, final BHSDCodec codec, final boolean hasHi)
             throws IOException, Pack200Exception {
         return parseFlags(name, in, counts, hasHi ? codec : null, codec);
     }
 
     /**
      * Parses <i>count</i> references from {@code in}, using {@code codec} to decode the values as indexes into {@code reference} (which is populated prior to
      * this call). An exception is thrown if a decoded index falls outside the range [0..reference.length-1].
      *
      * @param name      the band name
      * @param in        the input stream to read from
      * @param codec     the BHSDCodec to use for decoding
      * @param count     the number of references to decode
      * @param reference the array of values to use for the references
      * @return Parsed references.
      *
      * @throws IOException      if a problem occurs during reading from the underlying stream
      * @throws Pack200Exception if a problem occurs with an unexpected value or unsupported Codec
      */
     public String[] parseReferences(final String name, final InputStream in, final BHSDCodec codec, final int count, final String[] reference)
             throws IOException, Pack200Exception {
         return parseReferences(name, in, codec, new int[] { count }, reference)[0];
     }
 
     /**
      * Parses <i>count</i> references from {@code in}, using {@code codec} to decode the values as indexes into {@code reference} (which is populated prior to
      * this call). An exception is thrown if a decoded index falls outside the range [0..reference.length-1]. Unlike the other parseReferences, this
      * post-processes the result into an array of results.
      *
      * @param name      TODO
      * @param in        the input stream to read from
      * @param codec     the BHSDCodec to use for decoding
      * @param counts    the numbers of references to decode for each array entry
      * @param reference the array of values to use for the references
      * @return Parsed references.
      *
      * @throws IOException      if a problem occurs during reading from the underlying stream
      * @throws Pack200Exception if a problem occurs with an unexpected value or unsupported Codec
      */
     public String[][] parseReferences(final String name, final InputStream in, final BHSDCodec codec, final int[] counts, final String[] reference)
             throws IOException, Pack200Exception {
         final int count = counts.length;
         if (count == 0) {
             return new String[][] { {} };
         }
         int sum = 0;
         for (int i = 0; i < count; i++) {
             sum += counts[i];
         }
         // TODO Merge the decode and parsing of a multiple structure into one
         final int[] indices = decodeBandInt(name, in, codec, sum);
         final String[] result1 = new String[sum];
         for (int i1 = 0; i1 < sum; i1++) {
             final int index = indices[i1];
             if (index < 0 || index >= reference.length) {
                 throw new Pack200Exception("Something has gone wrong during parsing references, index = " + index + ", array size = " + reference.length);
             }
             result1[i1] = reference[index];
         }
         // TODO Merge the decode and parsing of a multiple structure into one
         final String[][] result = new String[count][];
         int pos = 0;
         for (int i = 0; i < count; i++) {
             final int num = counts[i];
             result[i] = new String[num];
             System.arraycopy(result1, pos, result[i], 0, num);
             pos += num;
         }
         return result;
     }
 
     public abstract void read(InputStream inputStream) throws IOException, Pack200Exception;
 
     public abstract void unpack() throws IOException, Pack200Exception;
 
     public void unpack(final InputStream in) throws IOException, Pack200Exception {
         read(in);
         unpack();
     }
 
 }