package nom.tam.image.compression.bintable;
   
   /*
    * #%L
    * nom.tam FITS library
    * %%
    * Copyright (C) 1996 - 2024 nom-tam-fits
    * %%
    * This is free and unencumbered software released into the public domain.
   *
   * Anyone is free to copy, modify, publish, use, compile, sell, or
   * distribute this software, either in source code form or as a compiled
   * binary, for any purpose, commercial or non-commercial, and by any
   * means.
   *
   * In jurisdictions that recognize copyright laws, the author or authors
   * of this software dedicate any and all copyright interest in the
   * software to the public domain. We make this dedication for the benefit
   * of the public at large and to the detriment of our heirs and
   * successors. We intend this dedication to be an overt act of
   * relinquishment in perpetuity of all present and future rights to this
   * software under copyright law.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
   * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
   * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
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  import java.io.IOException;
  import java.nio.Buffer;
  import java.nio.ByteBuffer;
  import java.util.Arrays;
  
  import nom.tam.fits.BinaryTable;
  import nom.tam.fits.compression.algorithm.api.ICompressorControl;
  import nom.tam.image.compression.hdu.CompressedTableData;
  import nom.tam.util.ArrayOutputStream;
  import nom.tam.util.ByteBufferOutputStream;
  import nom.tam.util.ColumnTable;
  import nom.tam.util.FitsOutputStream;
  import nom.tam.util.type.ElementType;
  
  /**
   * (<i>for internal use</i>) Handles the compression of binary table 'tiles'.
   */
  @SuppressWarnings("javadoc")
  public class BinaryTableTileCompressor extends BinaryTableTile {
  
      private static final double NORMAL_OVERHEAD = 1.2;
  
      private static final int MINIMUM_EXTRA_SPACE = 1024;
  
      private final CompressedTableData compressed;
  
      /** The original (uncompressed) binary table, if known (otherwise we cannot handle variable-sized columns) */
      private BinaryTable orig;
  
      // Intermediate data stored between parallel compression and serialization steps.
      private byte[][] compressedBytes;
      private long[][] cdesc;
      private Object udesc;
  
      /**
       * @deprecated (<i>for internal use</i>) Its visibility will be reduced in the future, not to mention that it should
       *                 take a BinaryTable as its argument with heap and all. It cannot be used for compressing binary
       *                 tables with variable-length columns.
       */
      public BinaryTableTileCompressor(CompressedTableData compressedTable, ColumnTable<?> columnTable,
              BinaryTableTileDescription description) {
          super(columnTable, description);
          this.compressed = compressedTable;
      }
  
      /**
       * (<i>for internal use</i>)
       * 
       * @param compressedTable a compressed table in which we'll insert the data for the compressed tile
       * @param table           the original uncompressed binary table
       * @param description     the tile description.
       */
      public BinaryTableTileCompressor(CompressedTableData compressedTable, BinaryTable table,
              BinaryTableTileDescription description) {
          this(compressedTable, table.getData(), description);
          this.orig = table;
      }
  
      private int getCushion(int size, double factor) throws IllegalStateException {
          long lsize = (long) Math.ceil(size * factor + MINIMUM_EXTRA_SPACE);
          return (lsize > Integer.MAX_VALUE) ? Integer.MAX_VALUE : (int) lsize;
      }
  
      private byte[] getCompressedBytes(ByteBuffer buffer, ElementType<?> t, ICompressorControl compressor) {
          buffer.flip();
  
         // give the compression 10% more space and a minimum of 1024 bytes
         int need = getCushion(getUncompressedSizeInBytes(), NORMAL_OVERHEAD);
         ByteBuffer cbuf = ByteBuffer.allocateDirect(need);
 
         Buffer tb = t.asTypedBuffer(buffer);
 
         if (!compressor.compress(tb, cbuf, null)) {
             throw new IllegalStateException("Compression error");
         }
 
         cbuf.flip();
         byte[] cdata = new byte[cbuf.limit()];
         cbuf.get(cdata);
 
         buffer.clear();
 
         return cdata;
     }
 
     private void compressRegular() throws IOException {
         compressedBytes = new byte[1][];
 
         ByteBuffer buffer = ByteBuffer.allocateDirect(getUncompressedSizeInBytes());
         try (FitsOutputStream os = new FitsOutputStream(new ByteBufferOutputStream(buffer))) {
             data.write(os, rowStart, rowEnd, column);
         }
 
         compressedBytes[0] = getCompressedBytes(buffer, type, getCompressorControl());
     }
 
     private void compressVariable() throws IOException {
         int nRows = rowEnd - rowStart;
         boolean longPointers = orig.getDescriptor(column).hasLongPointers();
         long max = 0;
 
         udesc = longPointers ? new long[nRows][] : new int[nRows][2]; // Original Q or P type heap pointers
 
         // Find out what's the largest variable-sized entry and store the original pointers for the tile
         for (int r = 0; r < nRows; r++) {
             Object desc = data.getElement(rowStart + r, column);
             long n = 0;
 
             if (longPointers) {
                 ((long[][]) udesc)[r] = (long[]) desc;
                 n = ((long[]) desc)[0];
             } else {
                 ((int[][]) udesc)[r] = (int[]) desc;
                 n = ((int[]) desc)[0];
             }
 
             if (n > max) {
                 max = n;
             }
         }
 
         max *= type.size();
 
         // Uh-oh, we can only handle 32-bit address space...
         if (max > Integer.MAX_VALUE) {
             throw new IllegalStateException("Uncompressed data too large for Java arrays: max=" + max);
         }
 
         // Buffer for the original data chunks to compress
         ByteBuffer buffer = ByteBuffer.allocateDirect((int) max);
         ElementType<?> dataType = ElementType.forClass(orig.getDescriptor(column).getElementClass());
 
         ICompressorControl compressor = getCompressorControl(dataType.primitiveClass());
         compressedBytes = new byte[nRows][];
 
         for (int r = 0; r < nRows; r++) {
             try (FitsOutputStream os = new FitsOutputStream(new ByteBufferOutputStream(buffer))) {
                 // Get the VLA data from the heap
                 Object entry = orig.get(rowStart + r, column);
                 os.writeArray(entry);
             }
 
             compressedBytes[r] = getCompressedBytes(buffer, dataType, compressor);
         }
 
     }
 
     @Override
     public void run() {
         try {
             if (orig != null && orig.getDescriptor(column).isVariableSize()) {
                 // binary table with variable sized column
                 compressVariable();
             } else {
                 // regular column table with fixed width columns
                 compressRegular();
             }
         } catch (IOException e) {
             throw new IllegalStateException(e.getMessage(), e);
         }
     }
 
     private Object setCompressedData(byte[] data) {
         synchronized (compressed) {
             // Reset the stored heap pointers so we force a new location on the heap.
             Object p = compressed.getData().getElement(getTileIndex(), column);
             if (p instanceof long[]) {
                 Arrays.fill((long[]) p, 0L);
             } else {
                 Arrays.fill((int[]) p, 0);
             }
             compressed.getData().setElement(getTileIndex(), column, p);
 
             // Now set the variable size data, which we'll place on a new heap location.
             compressed.setElement(getTileIndex(), column, data);
 
             // Retrieve the heap pointers for the compressed data
             // We only really handle 32-bit heap descriptors...
             return compressed.getData().getElement(getTileIndex(), column);
         }
 
     }
 
     private void setRegularData() {
         setCompressedData(compressedBytes[0]);
 
         // Discard temporary resources.
         compressedBytes = null;
     }
 
     private void setVariableData() throws IOException {
         int nRows = compressedBytes.length;
         boolean longPointers = orig.getDescriptor(column).hasLongPointers();
 
         cdesc = new long[nRows][2]; // Compressed Q-type heap pointers
 
         ByteBuffer buffer = ByteBuffer
                 .allocateDirect((nRows * 2) * (Long.SIZE + (longPointers ? Long.BYTES : Integer.BYTES)));
 
         for (int r = 0; r < nRows; r++) {
             // Now set the variable size data, which we'll place on a new heap location.
             Object cp = setCompressedData(compressedBytes[r]);
 
             if (cp instanceof long[]) {
                 cdesc[r] = (long[]) cp;
             } else {
                 // Convert to 64-bit for saving / compressing pointers later
                 cdesc[r][0] = ((int[]) cp)[0];
                 cdesc[r][1] = ((int[]) cp)[1];
             }
         }
 
         try (ArrayOutputStream os = new FitsOutputStream(new ByteBufferOutputStream(buffer))) {
             // --- The fpack / funpack way ---
             // Serialize the original heap descritors
             os.writeArray(udesc);
             // Append the compressed heap descriptors
             os.writeArray(cdesc);
         }
 
         // Compress the combined descriptors with GZIP_1 -- and we'll store the pointers to that in the
         // compressed table
         setCompressedData(getCompressedBytes(buffer, ElementType.BYTE, getGZipCompressorControl()));
 
         // Discard temporary resources.
         compressedBytes = null;
         cdesc = null;
         udesc = null;
     }
 
     @Override
     public void waitForResult() {
         super.waitForResult();
 
         if (orig != null && orig.getDescriptor(column).isVariableSize()) {
             try {
                 setVariableData();
             } catch (IOException e) {
                 throw new IllegalStateException(e.getMessage(), e);
             }
         } else {
             setRegularData();
         }
 
     }
 
 }