package nom.tam.fits.compression.algorithm.rice;
   
   import java.nio.Buffer;
   import java.nio.ByteBuffer;
   import java.nio.IntBuffer;
   import java.nio.ShortBuffer;
   import java.util.logging.Logger;
   
   import nom.tam.fits.compression.algorithm.api.ICompressor;
  import nom.tam.fits.compression.algorithm.quant.QuantizeProcessor.DoubleQuantCompressor;
  import nom.tam.fits.compression.algorithm.quant.QuantizeProcessor.FloatQuantCompressor;
  import nom.tam.util.FitsIO;
  import nom.tam.util.type.ElementType;
  
  /*
   * #%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.
   * IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
   * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
   * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
   * OTHER DEALINGS IN THE SOFTWARE.
   * #L%
   */
  
  /**
   * (<i>for internal use</i>) The Rice compression algorithm. The original compression was designed by Rice, Yeh, and
   * Miller the code was written by Richard White at STScI at the STScI and included (ported to c and adapted) in cfitsio
   * by William Pence, NASA/GSFC. That code was then ported to java by R. van Nieuwenhoven. Later it was massively
   * refactored to harmonize the different compression algorithms and reduce the duplicate code pieces without obscuring
   * the algorithm itself as far as possible.
   *
   * @author     Richard White
   * @author     William Pence
   * @author     Richard van Nieuwenhoven
   *
   * @param  <T> the genetic type of NIO buffer on which this compressor operates.
   */
  @SuppressWarnings({"deprecation", "javadoc"})
  public abstract class RiceCompressor<T extends Buffer> implements ICompressor<T> {
  
      public static class ByteRiceCompressor extends RiceCompressor<ByteBuffer> {
  
          private ByteBuffer pixelBuffer;
  
          /**
           * Rice compression of byte streams with the default block size of 32.
           * 
           * @since  1.19.1
           * 
           * @author Attila Kovacs
           */
          public ByteRiceCompressor() {
              this(new RiceCompressOption());
          }
  
          public ByteRiceCompressor(RiceCompressOption option) {
              super(option);
          }
  
          @Override
          public boolean compress(ByteBuffer buffer, ByteBuffer writeBuffer) {
              pixelBuffer = buffer;
              super.compress(buffer.limit(), pixelBuffer.get(pixelBuffer.position()), new BitBuffer(writeBuffer));
              return true;
          }
  
          @Override
          public void decompress(ByteBuffer readBuffer, ByteBuffer buffer) {
              pixelBuffer = buffer;
              super.decompressBuffer(readBuffer, buffer.limit());
          }
  
          @Override
          protected int nextPixel() {
              return pixelBuffer.get();
          }
  
          @Override
         protected void nextPixel(int pixel) {
             pixelBuffer.put((byte) pixel);
         }
     }
 
     public static class DoubleRiceCompressor extends DoubleQuantCompressor {
 
         public DoubleRiceCompressor(RiceQuantizeCompressOption options) throws ClassCastException {
             super(options, new IntRiceCompressor((RiceCompressOption) options.getCompressOption()));
         }
     }
 
     public static class FloatRiceCompressor extends FloatQuantCompressor {
 
         public FloatRiceCompressor(RiceQuantizeCompressOption options) throws ClassCastException {
             super(options, new IntRiceCompressor((RiceCompressOption) options.getCompressOption()));
         }
     }
 
     public static class IntRiceCompressor extends RiceCompressor<IntBuffer> {
 
         private IntBuffer pixelBuffer;
 
         /**
          * Rice compression of 32-bit integer streams with the default block size of 32.
          * 
          * @since  1.19.1
          * 
          * @author Attila Kovacs
          */
         public IntRiceCompressor() {
             this(new RiceCompressOption());
         }
 
         public IntRiceCompressor(RiceCompressOption option) {
             super(option);
         }
 
         @Override
         public boolean compress(IntBuffer buffer, ByteBuffer writeBuffer) {
             pixelBuffer = buffer;
             super.compress(buffer.limit(), pixelBuffer.get(pixelBuffer.position()), new BitBuffer(writeBuffer));
             return true;
         }
 
         @Override
         public void decompress(ByteBuffer readBuffer, IntBuffer buffer) {
             pixelBuffer = buffer;
             super.decompressBuffer(readBuffer, buffer.limit());
         }
 
         @Override
         protected int nextPixel() {
             return pixelBuffer.get();
         }
 
         @Override
         protected void nextPixel(int pixel) {
             pixelBuffer.put(pixel);
         }
     }
 
     public static class ShortRiceCompressor extends RiceCompressor<ShortBuffer> {
 
         private ShortBuffer pixelBuffer;
 
         /**
          * Rice compression of 16-bit integer streams with the default block size of 32.
          * 
          * @since  1.19.1
          * 
          * @author Attila Kovacs
          */
         public ShortRiceCompressor() {
             this(new RiceCompressOption());
         }
 
         public ShortRiceCompressor(RiceCompressOption option) {
             super(option);
         }
 
         @Override
         public boolean compress(ShortBuffer buffer, ByteBuffer writeBuffer) {
             pixelBuffer = buffer;
             super.compress(buffer.limit(), pixelBuffer.get(pixelBuffer.position()), new BitBuffer(writeBuffer));
             return true;
         }
 
         @Override
         public void decompress(ByteBuffer readBuffer, ShortBuffer buffer) {
             pixelBuffer = buffer;
             super.decompressBuffer(readBuffer, buffer.limit());
         }
 
         @Override
         protected int nextPixel() {
             return pixelBuffer.get();
         }
 
         @Override
         protected void nextPixel(int pixel) {
             pixelBuffer.put((short) pixel);
         }
     }
 
     /**
      * mask to convert a "unsigned" byte to a long.
      */
     private static final long UNSIGNED_BYTE_MASK = 0xFFL;
 
     /**
      * mask to convert a "unsigned" short to a long.
      */
     private static final long UNSIGNED_SHORT_MASK = 0xFFFFL;
 
     /**
      * mask to convert a "unsigned" int to a long.
      */
     private static final long UNSIGNED_INTEGER_MASK = 0xFFFFFFFFL;
 
     /**
      * logger to log to.
      */
     private static final Logger LOG = Logger.getLogger(RiceCompressor.class.getName());
 
     private static final int BITS_OF_1_BYTE = 8;
 
     private static final int BITS_PER_BYTE = 8;
 
     private static final int BYTE_MASK = 0xff;
 
     private static final int FS_BITS_FOR_BYTE = 3;
 
     private static final int FS_BITS_FOR_INT = 5;
 
     private static final int FS_BITS_FOR_SHORT = 4;
 
     private static final int FS_MAX_FOR_BYTE = 6;
 
     private static final int FS_MAX_FOR_INT = 25;
 
     private static final int FS_MAX_FOR_SHORT = 14;
 
     /*
      * nonzero_count is lookup table giving number of bits in 8-bit values not including leading zeros used in
      * fits_rdecomp, fits_rdecomp_short and fits_rdecomp_byte.
      *
      * @formatter:off
      */
     private static final int[] NONZERO_COUNT = {0, 1, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 5, 5,
             5, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
             6, 6, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
             7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 8,
             8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
             8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
             8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
             8, 8, 8, 8, 8, 8, 8, 8, 8};
     // @formatter:on
 
     private final int bBits;
 
     private final int bitsPerPixel;
 
     private final int blockSize;
 
     private final int fsBits;
 
     private final int fsMax;
 
     private RiceCompressor(RiceCompressOption option) throws UnsupportedOperationException {
         blockSize = option.getBlockSize();
         if (option.getBytePix() == ElementType.BYTE.size()) {
             fsBits = FS_BITS_FOR_BYTE;
             fsMax = FS_MAX_FOR_BYTE;
             bitsPerPixel = FitsIO.BITS_OF_1_BYTE;
         } else if (option.getBytePix() == ElementType.SHORT.size()) {
             fsBits = FS_BITS_FOR_SHORT;
             fsMax = FS_MAX_FOR_SHORT;
             bitsPerPixel = FitsIO.BITS_OF_2_BYTES;
         } else if (option.getBytePix() == ElementType.INT.size()) {
             fsBits = FS_BITS_FOR_INT;
             fsMax = FS_MAX_FOR_INT;
             bitsPerPixel = FitsIO.BITS_OF_4_BYTES;
         } else {
             throw new UnsupportedOperationException("Implemented for 1/2/4 bytes only");
         }
         /*
          * From bsize derive: FSBITS = # bits required to store FS FSMAX = maximum value for FS BBITS = bits/pixel for
          * direct coding
          */
         bBits = 1 << fsBits;
     }
 
     /**
      * <p>
      * undo mapping and differencing Note that some of these operations will overflow the unsigned int arithmetic --
      * that's OK, it all works out to give the right answers in the output file.
      * </p>
      * <p>
      * In java this is more complicated because of the missing unsigned integers. trying to simulate the behavior
      * </p>
      *
      * @param  lastpix the current last pix value
      * @param  diff    the difference to "add"
      *
      * @return         return the new lastpiy value
      */
     private long undoMappingAndDifferencing(long lastpix, long diff) {
         diff &= UNSIGNED_INTEGER_MASK;
         if ((diff & 1) == 0) {
             diff = diff >>> 1;
         } else {
             diff = diff >>> 1 ^ UNSIGNED_INTEGER_MASK;
         }
         lastpix = diff + lastpix & UNSIGNED_INTEGER_MASK;
         nextPixel((int) lastpix);
         return lastpix;
     }
 
     /**
      * compress the integer tiledImageOperation on a rise compressed byte buffer.
      *
      * @param dataLength length of the data to compress
      * @param firstPixel the value of the first pixel
      * @param buffer     the buffer to write to
      */
     protected void compress(final int dataLength, int firstPixel, BitBuffer buffer) {
         /* the first difference will always be zero */
         int lastpix = firstPixel;
         /* write out first int value to the first 4 bytes of the buffer */
         buffer.putInt(firstPixel, bitsPerPixel);
         int thisblock = blockSize;
         for (int i = 0; i < dataLength; i += blockSize) {
             /* last block may be shorter */
             if (dataLength - i < blockSize) {
                 thisblock = dataLength - i;
             }
             /*
              * Compute differences of adjacent pixels and map them to unsigned values. Note that this may overflow the
              * integer variables -- that's OK, because we can recover when decompressing. If we were compressing shorts
              * or bytes, would want to do this arithmetic with short/byte working variables (though diff will still be
              * passed as an int.) compute sum of mapped pixel values at same time use double precision for sum to allow
              * 32-bit integer inputs
              */
             long[] diff = new long[blockSize];
             double pixelsum = 0.0;
             int nextpix;
             /*
              * tiledImageOperation for differences mapped to non-negative values
              */
             for (int j = 0; j < thisblock; j++) {
                 nextpix = nextPixel();
                 long pdiff = (nextpix - lastpix);
                 diff[j] = (pdiff < 0 ? (pdiff << 1) ^ UNSIGNED_INTEGER_MASK : pdiff << 1) & UNSIGNED_INTEGER_MASK;
                 pixelsum += diff[j];
                 lastpix = nextpix;
             }
 
             /*
              * compute number of bits to split from sum
              */
             double dpsum = (pixelsum - thisblock / 2d - 1d) / thisblock;
             if (dpsum < 0) {
                 dpsum = 0.0;
             }
             long psum = (long) dpsum >> 1;
             int fs;
             for (fs = 0; psum > 0; fs++) { // NOSONAR
                 psum >>= 1;
             }
 
             /*
              * write the codes fsbits ID bits used to indicate split level
              */
             if (fs >= fsMax) {
                 /*
                  * Special high entropy case when FS >= fsmax Just write pixel difference values directly, no Rice
                  * coding at all.
                  */
                 buffer.putInt(fsMax + 1, fsBits);
                 for (int j = 0; j < thisblock; j++) {
                     buffer.putLong(diff[j], bBits);
                 }
             } else if (fs == 0 && pixelsum == 0) { // NOSONAR
                 /*
                  * special low entropy case when FS = 0 and pixelsum=0 (all pixels in block are zero.) Output a 0 and
                  * return
                  */
                 buffer.putInt(0, fsBits);
             } else {
                 /* normal case: not either very high or very low entropy */
                 buffer.putInt(fs + 1, fsBits);
                 int fsmask = (1 << fs) - 1;
                 /*
                  * local copies of bit buffer to improve optimization
                  */
                 int bitsToGo = buffer.missingBitsInCurrentByte();
                 int bitBuffer = buffer.bitbuffer() >> bitsToGo;
                 buffer.movePosition(bitsToGo - BITS_OF_1_BYTE);
                 for (int j = 0; j < thisblock; j++) {
                     int v = (int) diff[j];
                     int top = v >> fs;
                     /*
                      * top is coded by top zeros + 1
                      */
                     if (bitsToGo >= top + 1) {
                         bitBuffer <<= top + 1;
                         bitBuffer |= 1;
                         bitsToGo -= top + 1;
                     } else {
                         bitBuffer <<= bitsToGo;
                         buffer.putByte((byte) (bitBuffer & BYTE_MASK));
                         for (top -= bitsToGo; top >= BITS_OF_1_BYTE; top -= BITS_OF_1_BYTE) {
                             buffer.putByte((byte) 0);
                         }
                         bitBuffer = 1;
                         bitsToGo = BITS_OF_1_BYTE - 1 - top;
                     }
                     /*
                      * bottom FS bits are written without coding code is output_nbits, moved into this routine to reduce
                      * overheads This code potentially breaks if FS>24, so I am limiting FS to 24 by choice of FSMAX
                      * above.
                      */
                     if (fs > 0) {
                         bitBuffer <<= fs;
                         bitBuffer |= v & fsmask;
                         bitsToGo -= fs;
                         while (bitsToGo <= 0) {
                             buffer.putByte((byte) (bitBuffer >> -bitsToGo & BYTE_MASK));
                             bitsToGo += BITS_OF_1_BYTE;
                         }
                     }
                 }
                 buffer.putByte((byte) (bitBuffer & BYTE_MASK), BITS_OF_1_BYTE - bitsToGo);
             }
         }
         buffer.close();
     }
 
     /**
      * decompress the readbuffer and fill the pixelarray.
      *
      * @param readBuffer input buffer
      * @param nx         the number of pixel to uncompress
      */
     protected void decompressBuffer(final ByteBuffer readBuffer, final int nx) {
         /* first x bytes of input buffer contain the value of the first */
         /* x byte integer value, without any encoding */
         long lastpix = 0L;
         if (bitsPerPixel == ElementType.BYTE.bitPix()) {
             lastpix = readBuffer.get() & UNSIGNED_BYTE_MASK;
         } else if (bitsPerPixel == ElementType.SHORT.bitPix()) {
             lastpix = readBuffer.getShort() & UNSIGNED_SHORT_MASK;
         } else {
             // Must be (this.bitsPerPixel == ElementType.INT.bitPix())
             lastpix = readBuffer.getInt() & UNSIGNED_INTEGER_MASK;
         }
         long b = readBuffer.get() & BYTE_MASK; /* bit buffer */
         int nbits = BITS_PER_BYTE; /* number of bits remaining in b */
         for (int i = 0; i < nx;) {
             /* get the FS value from first fsbits */
             nbits -= fsBits;
             while (nbits < 0) {
                 b = b << BITS_PER_BYTE | readBuffer.get() & BYTE_MASK;
                 nbits += BITS_PER_BYTE;
             }
             long fs = (b >>> nbits) - 1L;
 
             b &= (1 << nbits) - 1;
             /* loop over the next block */
             int imax = i + blockSize;
             if (imax > nx) {
                 imax = nx;
             }
             if (fs < 0) {
                 /* low-entropy case, all zero differences */
                 for (; i < imax; i++) {
                     nextPixel((int) lastpix);
                 }
             } else if (fs == fsMax) {
                 /* high-entropy case, directly coded pixel values */
                 for (; i < imax; i++) {
                     int k = bBits - nbits;
                     long diff = b << k;
                     for (k -= BITS_PER_BYTE; k >= 0; k -= BITS_PER_BYTE) {
                         b = readBuffer.get() & BYTE_MASK;
                         diff |= b << k;
                     }
                     if (nbits > 0) {
                         b = readBuffer.get() & BYTE_MASK;
                         diff |= b >>> -k;
                         b &= (1 << nbits) - 1L;
                     } else {
                         b = 0;
                     }
                     lastpix = undoMappingAndDifferencing(lastpix, diff);
                 }
             } else {
                 /* normal case, Rice coding */
                 for (; i < imax; i++) {
                     /* count number of leading zeros */
                     while (b == 0) {
                         nbits += BITS_PER_BYTE;
                         b = readBuffer.get() & BYTE_MASK;
                     }
                     long nzero = nbits - NONZERO_COUNT[(int) (b & BYTE_MASK)];
                     nbits -= nzero + 1;
                     /* flip the leading one-bit */
                     b ^= 1 << nbits;
                     /* get the FS trailing bits */
                     nbits -= fs;
                     while (nbits < 0) {
                         b = b << BITS_PER_BYTE | readBuffer.get() & BYTE_MASK;
                         nbits += BITS_PER_BYTE;
                     }
                     long diff = nzero << fs | b >> nbits;
                     b &= (1 << nbits) - 1L;
 
                     lastpix = undoMappingAndDifferencing(lastpix, diff);
                 }
             }
         }
         if (readBuffer.limit() > readBuffer.position()) {
             LOG.warning("decompressing left over some extra bytes got: " + readBuffer.limit() + " but needed only "
                     + readBuffer.position());
         }
 
     }
 
     protected abstract int nextPixel();
 
     protected abstract void nextPixel(int pixel);
 
 }