src/share/classes/sun/java2d/pipe/RenderBuffer.java

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   1 /*
   2  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package sun.java2d.pipe;
  27 
  28 import sun.misc.Unsafe;
  29 
  30 import javax.tools.annotation.GenerateNativeHeader;
  31 
  32 /**
  33  * The RenderBuffer class is a simplified, high-performance, Unsafe wrapper
  34  * used for buffering rendering operations in a single-threaded rendering
  35  * environment.  It's functionality is similar to the ByteBuffer and related
  36  * NIO classes.  However, the methods in this class perform little to no
  37  * alignment or bounds checks for performance reasons.  Therefore, it is
  38  * the caller's responsibility to ensure that all put() calls are properly
  39  * aligned and within bounds:
  40  *   - int and float values must be aligned on 4-byte boundaries
  41  *   - long and double values must be aligned on 8-byte boundaries
  42  *
  43  * This class only includes the bare minimum of methods to support
  44  * single-threaded rendering.  For example, there is no put(double[]) method
  45  * because we currently have no need for such a method in the STR classes.
  46  */
  47 /* No native methods here, but the constants are needed in the supporting JNI code */
  48 @GenerateNativeHeader
  49 public class RenderBuffer {
  50 
  51     /**
  52      * These constants represent the size of various data types (in bytes).
  53      */
  54     protected static final long SIZEOF_BYTE   = 1L;
  55     protected static final long SIZEOF_SHORT  = 2L;
  56     protected static final long SIZEOF_INT    = 4L;
  57     protected static final long SIZEOF_FLOAT  = 4L;
  58     protected static final long SIZEOF_LONG   = 8L;
  59     protected static final long SIZEOF_DOUBLE = 8L;
  60 
  61     /**
  62      * Represents the number of elements at which we have empirically
  63      * determined that the average cost of a JNI call exceeds the expense
  64      * of an element by element copy.  In other words, if the number of
  65      * elements in an array to be copied exceeds this value, then we should
  66      * use the copyFromArray() method to complete the bulk put operation.
  67      * (This value can be adjusted if the cost of JNI downcalls is reduced
  68      * in a future release.)


   1 /*
   2  * Copyright (c) 2005, 2013, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package sun.java2d.pipe;
  27 
  28 import sun.misc.Unsafe;
  29 

  30 
  31 /**
  32  * The RenderBuffer class is a simplified, high-performance, Unsafe wrapper
  33  * used for buffering rendering operations in a single-threaded rendering
  34  * environment.  It's functionality is similar to the ByteBuffer and related
  35  * NIO classes.  However, the methods in this class perform little to no
  36  * alignment or bounds checks for performance reasons.  Therefore, it is
  37  * the caller's responsibility to ensure that all put() calls are properly
  38  * aligned and within bounds:
  39  *   - int and float values must be aligned on 4-byte boundaries
  40  *   - long and double values must be aligned on 8-byte boundaries
  41  *
  42  * This class only includes the bare minimum of methods to support
  43  * single-threaded rendering.  For example, there is no put(double[]) method
  44  * because we currently have no need for such a method in the STR classes.
  45  */


  46 public class RenderBuffer {
  47 
  48     /**
  49      * These constants represent the size of various data types (in bytes).
  50      */
  51     protected static final long SIZEOF_BYTE   = 1L;
  52     protected static final long SIZEOF_SHORT  = 2L;
  53     protected static final long SIZEOF_INT    = 4L;
  54     protected static final long SIZEOF_FLOAT  = 4L;
  55     protected static final long SIZEOF_LONG   = 8L;
  56     protected static final long SIZEOF_DOUBLE = 8L;
  57 
  58     /**
  59      * Represents the number of elements at which we have empirically
  60      * determined that the average cost of a JNI call exceeds the expense
  61      * of an element by element copy.  In other words, if the number of
  62      * elements in an array to be copied exceeds this value, then we should
  63      * use the copyFromArray() method to complete the bulk put operation.
  64      * (This value can be adjusted if the cost of JNI downcalls is reduced
  65      * in a future release.)