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+/* Buffers.java --
+   Copyright (C) 2000, 2002, 2004  Free Software Foundation
+
+This file is part of GNU Classpath.
+
+GNU Classpath is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+GNU Classpath is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU Classpath; see the file COPYING.  If not, write to the
+Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+02110-1301 USA.
+
+Linking this library statically or dynamically with other modules is
+making a combined work based on this library.  Thus, the terms and
+conditions of the GNU General Public License cover the whole
+combination.
+
+As a special exception, the copyright holders of this library give you
+permission to link this library with independent modules to produce an
+executable, regardless of the license terms of these independent
+modules, and to copy and distribute the resulting executable under
+terms of your choice, provided that you also meet, for each linked
+independent module, the terms and conditions of the license of that
+module.  An independent module is a module which is not derived from
+or based on this library.  If you modify this library, you may extend
+this exception to your version of the library, but you are not
+obligated to do so.  If you do not wish to do so, delete this
+exception statement from your version. */
+
+
+package gnu.java.awt;
+
+import java.awt.image.DataBuffer;
+import java.awt.image.DataBufferByte;
+import java.awt.image.DataBufferDouble;
+import java.awt.image.DataBufferFloat;
+import java.awt.image.DataBufferInt;
+import java.awt.image.DataBufferShort;
+import java.awt.image.DataBufferUShort;
+
+/** 
+ * Utility class for creating and accessing data buffers of arbitrary
+ * data types.
+ */
+public final class Buffers
+{
+  /**
+   * Create a data buffer of a particular type.
+   *
+   * @param dataType the desired data type of the buffer.
+   * @param data an array containing data, or null
+   * @param size the size of the data buffer bank
+   */
+  public static DataBuffer createBuffer(int dataType, Object data,
+					int size)
+  {
+    if (data == null) return createBuffer(dataType, size, 1);
+
+    return createBufferFromData(dataType, data, size);
+  }
+
+
+  /**
+   * Create a data buffer of a particular type.
+   *
+   * @param dataType the desired data type of the buffer.
+   * @param size the size of the data buffer bank
+   */
+  public static DataBuffer createBuffer(int dataType, int size) {
+    return createBuffer(dataType, size, 1);
+  }
+
+  /**
+   * Create a data buffer of a particular type.
+   *
+   * @param dataType the desired data type of the buffer.
+   * @param size the size of the data buffer bank
+   * @param numBanks the number of banks the buffer should have
+   */
+  public static DataBuffer createBuffer(int dataType, int size, int numBanks)
+  {
+    switch (dataType)
+      {
+      case DataBuffer.TYPE_BYTE:
+	return new DataBufferByte(size, numBanks);
+      case DataBuffer.TYPE_SHORT:
+	return new DataBufferShort(size, numBanks);
+      case DataBuffer.TYPE_USHORT:
+	return new DataBufferUShort(size, numBanks);
+      case DataBuffer.TYPE_INT:
+	return new DataBufferInt(size, numBanks);
+      case DataBuffer.TYPE_FLOAT:
+	return new DataBufferFloat(size, numBanks);
+      case DataBuffer.TYPE_DOUBLE:
+	return new DataBufferDouble(size, numBanks);
+      default:
+	throw new UnsupportedOperationException();
+      }
+  }
+  
+  /**
+   * Create a data buffer of a particular type.
+   *
+   * @param dataType the desired data type of the buffer
+   * @param data an array containing the data
+   * @param size the size of the data buffer bank
+   */
+  public static DataBuffer createBufferFromData(int dataType, Object data,
+						int size)
+  {
+    switch (dataType)
+      {
+      case DataBuffer.TYPE_BYTE:
+	return new DataBufferByte((byte[]) data, size);
+      case DataBuffer.TYPE_SHORT:
+	return new DataBufferShort((short[]) data, size);
+      case DataBuffer.TYPE_USHORT:
+	return new DataBufferUShort((short[]) data, size);
+      case DataBuffer.TYPE_INT:
+	return new DataBufferInt((int[]) data, size);
+      case DataBuffer.TYPE_FLOAT:
+	return new DataBufferFloat((float[]) data, size);
+      case DataBuffer.TYPE_DOUBLE:
+	return new DataBufferDouble((double[]) data, size);
+      default:
+	throw new UnsupportedOperationException();
+      }
+  }
+
+  /** 
+   * Return the data array of a data buffer, regardless of the data
+   * type.
+   *
+   * @return an array of primitive values. The actual array type
+   * depends on the data type of the buffer.
+   */
+  public static Object getData(DataBuffer buffer)
+  {
+    if (buffer instanceof DataBufferByte)
+      return ((DataBufferByte) buffer).getData();
+
+    if (buffer instanceof DataBufferShort)
+      return ((DataBufferShort) buffer).getData();
+
+    if (buffer instanceof DataBufferUShort)
+      return ((DataBufferUShort) buffer).getData();
+
+    if (buffer instanceof DataBufferInt)
+      return ((DataBufferInt) buffer).getData();
+
+    if (buffer instanceof DataBufferFloat)
+      return ((DataBufferFloat) buffer).getData();
+
+    if (buffer instanceof DataBufferDouble)
+      return ((DataBufferDouble) buffer).getData();
+
+    throw new ClassCastException("Unknown data buffer type");
+  }
+
+    
+  /**
+   * Copy data from array contained in data buffer, much like
+   * System.arraycopy. Create a suitable destination array if the
+   * given destination array is null.
+   */
+  public static Object getData(DataBuffer src, int srcOffset,
+			       Object dest,  int destOffset,
+			       int length)
+  {
+    Object from;
+    if (src instanceof DataBufferByte)
+      {
+	from = ((DataBufferByte) src).getData();
+	if (dest == null) dest = new byte[length+destOffset];
+      }
+    else if (src instanceof DataBufferShort)
+      {
+	from = ((DataBufferShort) src).getData();
+	if (dest == null) dest = new short[length+destOffset];
+      }
+    else if (src instanceof DataBufferUShort)
+      {
+	from = ((DataBufferUShort) src).getData();
+	if (dest == null) dest = new short[length+destOffset];
+      }
+    else if (src instanceof DataBufferInt)
+      {
+	from = ((DataBufferInt) src).getData();
+	if (dest == null) dest = new int[length+destOffset];
+      }
+    else if (src instanceof DataBufferFloat)
+      {
+	from = ((DataBufferFloat) src).getData();
+	if (dest == null) dest = new float[length+destOffset];
+      }
+    else if (src instanceof DataBufferDouble)
+      {
+	from = ((DataBufferDouble) src).getData();
+	if (dest == null) dest = new double[length+destOffset];
+      }
+    else
+      {
+	throw new ClassCastException("Unknown data buffer type");
+      }
+    
+    System.arraycopy(from, srcOffset, dest, destOffset, length);
+    return dest;
+  }
+  
+  /**
+   * @param bits the width of a data element measured in bits
+   *
+   * @return the smallest data type that can store data elements of
+   * the given number of bits, without any truncation.
+   */
+  public static int smallestAppropriateTransferType(int bits)
+  {
+    if (bits <= 8)
+      {
+	return DataBuffer.TYPE_BYTE;
+      }
+    else if (bits <= 16)
+      {
+	return DataBuffer.TYPE_USHORT;
+      } 
+    else if (bits <= 32)
+      {
+	return DataBuffer.TYPE_INT;
+      }
+    else
+      {
+	return DataBuffer.TYPE_UNDEFINED;
+      }
+  }
+}