/*
 * Copyright (c) 2008 Sun Microsystems, Inc. All Rights Reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 * 
 * - Redistribution of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * 
 * - Redistribution in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * 
 * Neither the name of Sun Microsystems, Inc. or the names of
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 * 
 * This software is provided "AS IS," without a warranty of any kind. ALL
 * EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES,
 * INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A
 * PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN
 * MICROSYSTEMS, INC. ("SUN") AND ITS LICENSORS SHALL NOT BE LIABLE FOR
 * ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR
 * DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES. IN NO EVENT WILL SUN OR
 * ITS LICENSORS BE LIABLE FOR ANY LOST REVENUE, PROFIT OR DATA, OR FOR
 * DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL, INCIDENTAL OR PUNITIVE
 * DAMAGES, HOWEVER CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY,
 * ARISING OUT OF THE USE OF OR INABILITY TO USE THIS SOFTWARE, EVEN IF
 * SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
 * 
 * You acknowledge that this software is not designed or intended for use
 * in the design, construction, operation or maintenance of any nuclear
 * facility.
 * 
 * Sun gratefully acknowledges that this software was originally authored
 * and developed by Kenneth Bradley Russell and Christopher John Kline.
 */

package javax.media.opengl.util;

import javax.media.opengl.GL;
import javax.media.opengl.GL2;
import javax.media.opengl.GL2ES2;
import javax.media.opengl.GLException;
import javax.media.opengl.GLProfile;
import com.sun.opengl.impl.GLReflection;

import java.nio.*;
import java.util.*;

import java.lang.reflect.*;

/** Utility routines for dealing with direct buffers. */

public class BufferUtil {
  public static final int SIZEOF_BYTE = 1;
  public static final int SIZEOF_SHORT = 2;
  public static final int SIZEOF_INT = 4;
  public static final int SIZEOF_FLOAT = 4;
  public static final int SIZEOF_LONG = -1;    // not supported
  public static final int SIZEOF_DOUBLE = -1;  // not supported

  public static final int sizeOfGLType(int glType) {
        switch (glType) {
            case GL.GL_UNSIGNED_BYTE:
                return SIZEOF_BYTE;
            case GL.GL_BYTE:
                return SIZEOF_BYTE;
            case GL.GL_UNSIGNED_SHORT:
                return SIZEOF_SHORT;
            case GL.GL_SHORT:
                return SIZEOF_SHORT;
            case GL.GL_FLOAT:
                return SIZEOF_FLOAT;
            case GL.GL_FIXED:
                return SIZEOF_INT;
            case GL2ES2.GL_INT:
                return SIZEOF_INT;
            case GL2ES2.GL_UNSIGNED_INT:
                return SIZEOF_INT;
            case GL2.GL_DOUBLE:
                return SIZEOF_DOUBLE;
        }
        return -1;
  }

  public static final int sizeOfBufferElem(Buffer buffer) {
        if (buffer == null) {
            return 0;
        }
        if (buffer instanceof ByteBuffer) {
            return BufferUtil.SIZEOF_BYTE;
        } else if (buffer instanceof IntBuffer) {
            return BufferUtil.SIZEOF_INT;
        } else if (buffer instanceof ShortBuffer) {
            return BufferUtil.SIZEOF_SHORT;
        } else if (buffer instanceof FloatBuffer) {
            return BufferUtil.SIZEOF_FLOAT;
        }
        throw new RuntimeException("Unexpected buffer type " +
                                   buffer.getClass().getName());
  }

  private BufferUtil() {}

  //----------------------------------------------------------------------
  // Allocation routines
  //

  public static final Buffer newGLBuffer(int glType, int numElements) {
        switch (glType) {
            case GL.GL_UNSIGNED_BYTE:
            case GL.GL_BYTE:
                return newByteBuffer(numElements);
            case GL.GL_UNSIGNED_SHORT:
            case GL.GL_SHORT:
                return newShortBuffer(numElements);
            case GL.GL_FLOAT:
                return newFloatBuffer(numElements);
            case GL.GL_FIXED:
            case GL2ES2.GL_INT:
            case GL2ES2.GL_UNSIGNED_INT:
                return newIntBuffer(numElements);
        }
        return null;
  }

  public static final Buffer sliceGLBuffer(ByteBuffer parent, int bytePos, int byteLen, int glType) {
        if(parent==null || byteLen==0) return null;
        parent.position(bytePos);
        parent.limit(bytePos + byteLen);

        switch (glType) {
            case GL.GL_UNSIGNED_BYTE:
            case GL.GL_BYTE:
                return parent.slice();
            case GL.GL_UNSIGNED_SHORT:
            case GL.GL_SHORT:
                return parent.asShortBuffer();
            case GL.GL_FLOAT:
                return parent.asFloatBuffer();
            case GL.GL_FIXED:
            case GL2ES2.GL_INT:
            case GL2ES2.GL_UNSIGNED_INT:
                return parent.asIntBuffer();
        }
        return null;
  }

  /** Allocates a new direct ByteBuffer with the specified number of
      elements. The returned buffer will have its byte order set to
      the host platform's native byte order. */
  public static ByteBuffer newByteBuffer(int numElements) {
    ByteBuffer bb = ByteBuffer.allocateDirect(numElements);
    nativeOrder(bb);
    return bb;
  }
    
  public static ByteBuffer newByteBuffer(byte[] values, int offset, int len) {
    ByteBuffer bb = newByteBuffer(len);
    bb.put(values, offset, len);
    bb.rewind();
    return bb;
  }
    
  public static ByteBuffer newByteBuffer(byte[] values, int offset) {
    return newByteBuffer(values, offset, values.length-offset);
  }
    
  public static ByteBuffer newByteBuffer(byte[] values) {
    return newByteBuffer(values, 0);
  }
    
  /** Allocates a new direct FloatBuffer with the specified number of
      elements. The returned buffer will have its byte order set to
      the host platform's native byte order. */
  public static FloatBuffer newFloatBuffer(int numElements) {
    ByteBuffer bb = newByteBuffer(numElements * SIZEOF_FLOAT);
    return bb.asFloatBuffer();
  }
    
  public static FloatBuffer newFloatBuffer(float[] values, int offset, int len) {
    FloatBuffer bb = newFloatBuffer(len);
    bb.put(values, offset, len);
    bb.rewind();
    return bb;
  }
    
  public static FloatBuffer newFloatBuffer(float[] values, int offset) {
    return newFloatBuffer(values, 0, values.length-offset);
  }

  public static FloatBuffer newFloatBuffer(float[] values) {
    return newFloatBuffer(values, 0);
  }
    
  /** Allocates a new direct IntBuffer with the specified number of
      elements. The returned buffer will have its byte order set to
      the host platform's native byte order. */
  public static IntBuffer newIntBuffer(int numElements) {
    ByteBuffer bb = newByteBuffer(numElements * SIZEOF_INT);
    return bb.asIntBuffer();
  }
    
  public static IntBuffer newIntBuffer(int[] values, int offset, int len) {
    IntBuffer bb = newIntBuffer(len);
    bb.put(values, offset, len);
    bb.rewind();
    return bb;
  }
    
  public static IntBuffer newIntBuffer(int[] values, int offset) {
    return newIntBuffer(values, 0, values.length-offset);
  }

  public static IntBuffer newIntBuffer(int[] values) {
    return newIntBuffer(values, 0);
  }
    
    
  /** Allocates a new direct ShortBuffer with the specified number of
      elements. The returned buffer will have its byte order set to
      the host platform's native byte order. */
  public static ShortBuffer newShortBuffer(int numElements) {
    ByteBuffer bb = newByteBuffer(numElements * SIZEOF_SHORT);
    return bb.asShortBuffer();
  }

  public static ShortBuffer newShortBuffer(short[] values, int offset, int len) {
    ShortBuffer bb = newShortBuffer(len);
    bb.put(values, offset, len);
    bb.rewind();
    return bb;
  }
    
  public static ShortBuffer newShortBuffer(short[] values, int offset) {
    return newShortBuffer(values, 0, values.length-offset);
  }

  public static ShortBuffer newShortBuffer(short[] values) {
    return newShortBuffer(values, 0);
  }
    
    
  //----------------------------------------------------------------------
  // Copy routines (type-to-type)
  //
  
  /** Copies the <i>remaining</i> elements (as defined by
      <code>limit() - position()</code>) in the passed ByteBuffer into
      a newly-allocated direct ByteBuffer. The returned buffer will
      have its byte order set to the host platform's native byte
      order. The position of the newly-allocated buffer will be zero,
      and the position of the passed buffer is unchanged (though its
      mark is changed). */
  public static ByteBuffer copyByteBuffer(ByteBuffer orig) {
    ByteBuffer dest = newByteBuffer(orig.remaining());
    dest.put(orig);
    dest.rewind();
    return dest;
  }
  
  /** Copies the <i>remaining</i> elements (as defined by
      <code>limit() - position()</code>) in the passed FloatBuffer
      into a newly-allocated direct FloatBuffer. The returned buffer
      will have its byte order set to the host platform's native byte
      order. The position of the newly-allocated buffer will be zero,
      and the position of the passed buffer is unchanged (though its
      mark is changed). */
  public static FloatBuffer copyFloatBuffer(FloatBuffer orig) {
    return copyFloatBufferAsByteBuffer(orig).asFloatBuffer();
  }
  
  /** Copies the <i>remaining</i> elements (as defined by
      <code>limit() - position()</code>) in the passed IntBuffer
      into a newly-allocated direct IntBuffer. The returned buffer
      will have its byte order set to the host platform's native byte
      order. The position of the newly-allocated buffer will be zero,
      and the position of the passed buffer is unchanged (though its
      mark is changed). */
  public static IntBuffer copyIntBuffer(IntBuffer orig) {
    return copyIntBufferAsByteBuffer(orig).asIntBuffer();
  }
  
  /** Copies the <i>remaining</i> elements (as defined by
      <code>limit() - position()</code>) in the passed ShortBuffer
      into a newly-allocated direct ShortBuffer. The returned buffer
      will have its byte order set to the host platform's native byte
      order. The position of the newly-allocated buffer will be zero,
      and the position of the passed buffer is unchanged (though its
      mark is changed). */
  public static ShortBuffer copyShortBuffer(ShortBuffer orig) {
    return copyShortBufferAsByteBuffer(orig).asShortBuffer();
  }
  
  //----------------------------------------------------------------------
  // Copy routines (type-to-ByteBuffer)
  //
  
  /** Copies the <i>remaining</i> elements (as defined by
      <code>limit() - position()</code>) in the passed FloatBuffer
      into a newly-allocated direct ByteBuffer. The returned buffer
      will have its byte order set to the host platform's native byte
      order. The position of the newly-allocated buffer will be zero,
      and the position of the passed buffer is unchanged (though its
      mark is changed). */
  public static ByteBuffer copyFloatBufferAsByteBuffer(FloatBuffer orig) {
    ByteBuffer dest = newByteBuffer(orig.remaining() * SIZEOF_FLOAT);
    dest.asFloatBuffer().put(orig);
    dest.rewind();
    return dest;
  }
  
  /** Copies the <i>remaining</i> elements (as defined by
      <code>limit() - position()</code>) in the passed IntBuffer into
      a newly-allocated direct ByteBuffer. The returned buffer will
      have its byte order set to the host platform's native byte
      order. The position of the newly-allocated buffer will be zero,
      and the position of the passed buffer is unchanged (though its
      mark is changed). */
  public static ByteBuffer copyIntBufferAsByteBuffer(IntBuffer orig) {
    ByteBuffer dest = newByteBuffer(orig.remaining() * SIZEOF_INT);
    dest.asIntBuffer().put(orig);
    dest.rewind();
    return dest;
  }
  
  /** Copies the <i>remaining</i> elements (as defined by
      <code>limit() - position()</code>) in the passed ShortBuffer
      into a newly-allocated direct ByteBuffer. The returned buffer
      will have its byte order set to the host platform's native byte
      order. The position of the newly-allocated buffer will be zero,
      and the position of the passed buffer is unchanged (though its
      mark is changed). */
  public static ByteBuffer copyShortBufferAsByteBuffer(ShortBuffer orig) {
    ByteBuffer dest = newByteBuffer(orig.remaining() * SIZEOF_SHORT);
    dest.asShortBuffer().put(orig);
    dest.rewind();
    return dest;
  }

  //----------------------------------------------------------------------
  // Conversion routines 
  //

  public final static float[] getFloatArray(double[] source) {
      int i=source.length;
      float[] dest = new float[i--];
      while(i>=0) { dest[i]=(float)source[i]; i--; }
      return dest;
  }

  public static ByteBuffer nativeOrder(ByteBuffer buf) {
    if (!isCDCFP) {
      try {
        if (byteOrderClass == null) {
          byteOrderClass = Class.forName("java.nio.ByteOrder");
          orderMethod = ByteBuffer.class.getMethod("order", new Class[] { byteOrderClass });
          Method nativeOrderMethod = byteOrderClass.getMethod("nativeOrder", null);
          nativeOrderObject = nativeOrderMethod.invoke(null, null);
        }
      } catch (Throwable t) {
        // Must be running on CDC / FP
        isCDCFP = true;
      }

      if (!isCDCFP) {
        try {
          orderMethod.invoke(buf, new Object[] { nativeOrderObject });
        } catch (Throwable t) {
        }
      }
    }
    return buf;
  }

  //----------------------------------------------------------------------
  // Convenient GL put methods with generic target Buffer
  //
  public static void put(Buffer dest, Buffer v) {
    Class dClazz = dest.getClass();
    Class vClazz = v.getClass();
    if(!GLReflection.instanceOf(vClazz, dClazz.getName())) {
        throw new GLException("This array's dest class "+dClazz+" doesn't match the argument's Class: "+vClazz);
    }
    if(dest instanceof ByteBuffer) {
        ((ByteBuffer)dest).put((ByteBuffer)v);
    } else if(dest instanceof ShortBuffer) {
        ((ShortBuffer)dest).put((ShortBuffer)v);
    } else if(dest instanceof IntBuffer) {
        ((IntBuffer)dest).put((IntBuffer)v);
    } else if(dest instanceof FloatBuffer) {
        ((FloatBuffer)dest).put((FloatBuffer)v);
    }
  }

  public static void putb(Buffer dest, byte v) {
    if(dest instanceof ByteBuffer) {
        ((ByteBuffer)dest).put(v);
    } else if(dest instanceof ShortBuffer) {
        ((ShortBuffer)dest).put((short)v);
    } else if(dest instanceof IntBuffer) {
        ((IntBuffer)dest).put((int)v);
    } else {
        throw new GLException("Byte doesn't match Buffer Class: "+dest);
    }
  }

  public static void puts(Buffer dest, short v) {
    if(dest instanceof ShortBuffer) {
        ((ShortBuffer)dest).put(v);
    } else if(dest instanceof IntBuffer) {
        ((IntBuffer)dest).put((int)v);
    } else {
        throw new GLException("Short doesn't match Buffer Class: "+dest);
    }
  }

  public static void puti(Buffer dest, int v) {
    if(dest instanceof IntBuffer) {
        ((IntBuffer)dest).put(v);
    } else {
        throw new GLException("Integer doesn't match Buffer Class: "+dest);
    }
  }

  public static void putx(Buffer dest, int v) {
    puti(dest, v);
  }

  public static void putf(Buffer dest, float v) {
    if(dest instanceof FloatBuffer) {
        ((FloatBuffer)dest).put(v);
    } else if(dest instanceof IntBuffer) {
        ((IntBuffer)dest).put(FixedPoint.toFixed(v));
    } else {
        throw new GLException("Float doesn't match Buffer Class: "+dest);
    }
  }

  //----------------------------------------------------------------------
  // Internals only below this point
  //

  // NOTE that this work must be done reflectively at the present time
  // because this code must compile and run correctly on both CDC/FP and J2SE
  private static boolean isCDCFP;
  private static Class byteOrderClass;
  private static Object nativeOrderObject;
  private static Method orderMethod;

}