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/* Copyright (C) 2000, 2002, 2005  Free Software Foundation

This file is part of GNU Classpath.

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02110-1301 USA.

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making a combined work based on this library.  Thus, the terms and

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permission to link this library with independent modules to produce an

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package java.awt.image;

/**

 * Class that manages arrays of data elements. A data buffer consists

 * of one or more banks.  A bank is a continuous region of data

 * elements.

 *

 * @author Rolf W. Rasmussen (rolfwr@ii.uib.no)

 */

public abstract class DataBuffer

{

  /**

   * A constant representing a data type that uses <code>byte</code> primitives

   * as the storage unit.

   */

  public static final int TYPE_BYTE      =  0;

  /**

   * A constant representing a data type that uses <code>short</code>

   * primitives as the storage unit.

   */

  public static final int TYPE_USHORT    =  1;

  /**

   * A constant representing a data type that uses <code>short</code>

   * primitives as the storage unit.

   */

  public static final int TYPE_SHORT     =  2;

  /**

   * A constant representing a data type that uses <code>int</code>

   * primitives as the storage unit.

   */

  public static final int TYPE_INT       =  3;

  /**

   * A constant representing a data type that uses <code>float</code>

   * primitives as the storage unit.

   */

  public static final int TYPE_FLOAT     =  4;

  /**

   * A constant representing a data type that uses <code>double</code>

   * primitives as the storage unit.

   */

  public static final int TYPE_DOUBLE    =  5;

  /**

   * A constant representing an undefined data type.

   */

  public static final int TYPE_UNDEFINED = 32;

  /** The type of the data elements stored in the data buffer.  */

  protected int dataType;

  /** The number of banks in this buffer.  */

  protected int banks = 1;

  /** Offset into the default (0'th) bank). */

  protected int offset; // FIXME: Is offsets[0] always mirrored in offset?

  /** The size of the banks.  */

  protected int size;

  /** Offset into each bank.  */

  protected int[] offsets;

  /**

   * Creates a new <code>DataBuffer</code> with the specified data type and

   * size.  The <code>dataType</code> should be one of the constants

   * {@link #TYPE_BYTE}, {@link #TYPE_SHORT}, {@link #TYPE_USHORT},

   * {@link #TYPE_INT}, {@link #TYPE_FLOAT} and {@link #TYPE_DOUBLE}.

   * <p>

   * The physical (array-based) storage is allocated by a subclass.

   *

   * @param dataType the data type.

   * @param size the number of elements in the buffer.

   */

  protected DataBuffer(int dataType, int size)

  {

    this(dataType, size, 1);

  }

  /**

   * Creates a new <code>DataBuffer</code> with the specified data type,

   * size and number of banks.  The <code>dataType</code> should be one of

   * the constants {@link #TYPE_BYTE}, {@link #TYPE_SHORT},

   * {@link #TYPE_USHORT}, {@link #TYPE_INT}, {@link #TYPE_FLOAT} and

   * {@link #TYPE_DOUBLE}.

   * <p>

   * The physical (array-based) storage is allocated by a subclass.

   *

   * @param dataType the data type.

   * @param size the number of elements in the buffer.

   * @param numBanks the number of data banks.

   */

  protected DataBuffer(int dataType, int size, int numBanks) {

    this(dataType, size, numBanks, 0);

  }

  /**

   * Creates a new <code>DataBuffer</code> with the specified data type,

   * size and number of banks.  An offset (which applies to all banks) is

   * also specified.  The <code>dataType</code> should be one of

   * the constants {@link #TYPE_BYTE}, {@link #TYPE_SHORT},

   * {@link #TYPE_USHORT}, {@link #TYPE_INT}, {@link #TYPE_FLOAT} and

   * {@link #TYPE_DOUBLE}.

   * <p>

   * The physical (array-based) storage is allocated by a subclass.

   *

   * @param dataType the data type.

   * @param size the number of elements in the buffer.

   * @param numBanks the number of data banks.

   * @param offset the offset to the first element for all banks.

   */

  protected DataBuffer(int dataType, int size, int numBanks, int offset) {

    banks = numBanks;

    this.dataType = dataType;

    this.size = size;

    this.offset = offset;

    offsets = new int[ numBanks ];

    for(int i = 0; i < numBanks; i++ )

      offsets[i] = offset;

  }

  /**

   * Creates a new <code>DataBuffer</code> with the specified data type,

   * size and number of banks.  An offset (which applies to all banks) is

   * also specified.  The <code>dataType</code> should be one of

   * the constants {@link #TYPE_BYTE}, {@link #TYPE_SHORT},

   * {@link #TYPE_USHORT}, {@link #TYPE_INT}, {@link #TYPE_FLOAT} and

   * {@link #TYPE_DOUBLE}.

   * <p>

   * The physical (array-based) storage is allocated by a subclass.

   *

   * @param dataType the data type.

   * @param size the number of elements in the buffer.

   * @param numBanks the number of data banks.

   * @param offsets the offsets to the first element for all banks.

   *

   * @throws ArrayIndexOutOfBoundsException if

   *         <code>numBanks != offsets.length</code>.

   */

  protected DataBuffer(int dataType, int size, int numBanks, int[] offsets) {

    if (numBanks != offsets.length)

      throw new ArrayIndexOutOfBoundsException();

    this.dataType = dataType;

    this.size = size;

    banks = numBanks;

    this.offsets = offsets;

    offset = offsets[0];

  }

  /**

   * Returns the size (number of bits) of the specified data type. Valid types

   * are defined by the constants {@link #TYPE_BYTE}, {@link #TYPE_SHORT},

   * {@link #TYPE_USHORT}, {@link #TYPE_INT}, {@link #TYPE_FLOAT} and

   * {@link #TYPE_DOUBLE}.

   *

   * @param dataType the data type.

   * @return The number of bits for the specified data type.

   * @throws IllegalArgumentException if <code>dataType < 0</code> or

   *         <code>dataType > TYPE_DOUBLE</code>.

   */

  public static int getDataTypeSize(int dataType) {

    // Maybe this should be a lookup table instead.

    switch (dataType)

      {

      case TYPE_BYTE:

        return 8;

      case TYPE_USHORT:

      case TYPE_SHORT:

        return 16;

      case TYPE_INT:

      case TYPE_FLOAT:

        return 32;

      case TYPE_DOUBLE:

        return 64;

      default:

        throw new IllegalArgumentException();

      }

  }

  /**

   * Returns the type of the data elements in the data buffer.  Valid types

   * are defined by the constants {@link #TYPE_BYTE}, {@link #TYPE_SHORT},

   * {@link #TYPE_USHORT}, {@link #TYPE_INT}, {@link #TYPE_FLOAT} and

   * {@link #TYPE_DOUBLE}.

   *

   * @return The type.

   */

  public int getDataType()

  {

    return dataType;

  }

  /**

   * Returns the size of the data buffer.

   *

   * @return The size.

   */

  public int getSize()

  {

    return size;

  }

  /**

   * Returns the element offset for the first data bank.

   *

   * @return The element offset.

   */

  public int getOffset()

  {

    return offset;

  }

  /**

   * Returns the offsets for all the data banks used by this

   * <code>DataBuffer</code>.

   *

   * @return The offsets.

   */

  public int[] getOffsets()

  {

    if (offsets == null)

    {

      // is this necessary?

      offsets = new int[1];

      offsets[0] = offset;

    }

    return offsets;

  }

  /**

   * Returns the number of data banks for this <code>DataBuffer</code>.

   * @return The number of data banks.

   */

  public int getNumBanks()

  {

    return banks;

  }

  /**

   * Returns an element from the first data bank.  The offset (specified in

   * the constructor) is added to <code>i</code> before accessing the

   * underlying data array.

   *

   * @param i the element index.

   * @return The element.

   */

  public int getElem(int i)

  {

    return getElem(0, i);

  }

  /**

   * Returns an element from a particular data bank.  The offset (specified in

   * the constructor) is added to <code>i</code> before accessing the

   * underlying data array.

   *

   * @param bank the bank index.

   * @param i the element index.

   * @return The element.

   */

  public abstract int getElem(int bank, int i);

  /**

   * Sets an element in the first data bank.  The offset (specified in the

   * constructor) is added to <code>i</code> before updating the underlying

   * data array.

   *

   * @param i the element index.

   * @param val the new element value.

   */

  public void setElem(int i, int val)

  {

    setElem(0, i, val);

  }

  /**

   * Sets an element in a particular data bank.  The offset (specified in the

   * constructor) is added to <code>i</code> before updating the underlying

   * data array.

   *

   * @param bank the data bank index.

   * @param i the element index.

   * @param val the new element value.

   */

  public abstract void setElem(int bank, int i, int val);

  /**

   * Returns an element from the first data bank, converted to a

   * <code>float</code>.  The offset (specified in the constructor) is added

   * to <code>i</code> before accessing the underlying data array.

   *

   * @param i the element index.

   * @return The element.

   */

  public float getElemFloat(int i)

  {

    return getElem(i);

  }

  /**

   * Returns an element from a particular data bank, converted to a

   * <code>float</code>.  The offset (specified in the constructor) is

   * added to <code>i</code> before accessing the underlying data array.

   *

   * @param bank the bank index.

   * @param i the element index.

   * @return The element.

   */

  public float getElemFloat(int bank, int i)

  {

    return getElem(bank, i);

  }

  /**

   * Sets an element in the first data bank.  The offset (specified in the

   * constructor) is added to <code>i</code> before updating the underlying

   * data array.

   *

   * @param i the element index.

   * @param val the new element value.

   */

  public void setElemFloat(int i, float val)

  {

    setElem(i, (int) val);

  }

  /**

   * Sets an element in a particular data bank.  The offset (specified in the

   * constructor) is added to <code>i</code> before updating the underlying

   * data array.

   *

   * @param bank the data bank index.

   * @param i the element index.

   * @param val the new element value.

   */

  public void setElemFloat(int bank, int i, float val)

  {

    setElem(bank, i, (int) val);

  }

  /**

   * Returns an element from the first data bank, converted to a

   * <code>double</code>.  The offset (specified in the constructor) is added

   * to <code>i</code> before accessing the underlying data array.

   *

   * @param i the element index.

   * @return The element.

   */

  public double getElemDouble(int i)

  {

    return getElem(i);

  }

  /**

   * Returns an element from a particular data bank, converted to a

   * <code>double</code>.  The offset (specified in the constructor) is

   * added to <code>i</code> before accessing the underlying data array.

   *

   * @param bank the bank index.

   * @param i the element index.

   * @return The element.

   */

  public double getElemDouble(int bank, int i)

  {

    return getElem(bank, i);

  }

  /**

   * Sets an element in the first data bank.  The offset (specified in the

   * constructor) is added to <code>i</code> before updating the underlying

   * data array.

   *

   * @param i the element index.

   * @param val the new element value.

   */

  public void setElemDouble(int i, double val)

  {

    setElem(i, (int) val);

  }

  /**

   * Sets an element in a particular data bank.  The offset (specified in the

   * constructor) is added to <code>i</code> before updating the underlying

   * data array.

   *

   * @param bank the data bank index.

   * @param i the element index.

   * @param val the new element value.

   */

  public void setElemDouble(int bank, int i, double val)

  {

    setElem(bank, i, (int) val);

  }

}