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      1 /*
      2  * Copyright (c) 2000, 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.nio.ch;
     27 
     28 import java.nio.ByteBuffer;
     29 import sun.misc.*;
     30 
     31 
     32 /**
     33  * Manipulates a native array of iovec structs on Solaris:
     34  *
     35  * typedef struct iovec {
     36  *    caddr_t  iov_base;
     37       int      iov_len;
     38  * } iovec_t;
     39  *
     40  * @author Mike McCloskey
     41  * @since 1.4
     42  */
     43 
     44 class IOVecWrapper {
     45 
     46     // Miscellaneous constants
     47     private static final int BASE_OFFSET = 0;
     48     private static final int LEN_OFFSET;
     49     private static final int SIZE_IOVEC;
     50 
     51     // The iovec array
     52     private final AllocatedNativeObject vecArray;
     53 
     54     // Number of elements in iovec array
     55     private final int size;
     56 
     57     // Buffers and position/remaining corresponding to elements in iovec array
     58     private final ByteBuffer[] buf;
     59     private final int[] position;
     60     private final int[] remaining;
     61 
     62     // Shadow buffers for cases when original buffer is substituted
     63     private final ByteBuffer[] shadow;
     64 
     65     // Base address of this array
     66     final long address;
     67 
     68     // Address size in bytes
     69     static int addressSize;
     70 
     71     private static class Deallocator implements Runnable {
     72         private final AllocatedNativeObject obj;
     73         Deallocator(AllocatedNativeObject obj) {
     74             this.obj = obj;
     75         }
     76         public void run() {
     77             obj.free();
     78         }
     79     }
     80 
     81     // per thread IOVecWrapper
     82     private static final ThreadLocal<IOVecWrapper> cached =
     83         new ThreadLocal<IOVecWrapper>();
     84 
     85     private IOVecWrapper(int size) {
     86         this.size      = size;
     87         this.buf       = new ByteBuffer[size];
     88         this.position  = new int[size];
     89         this.remaining = new int[size];
     90         this.shadow    = new ByteBuffer[size];
     91         this.vecArray  = new AllocatedNativeObject(size * SIZE_IOVEC, false);
     92         this.address   = vecArray.address();
     93     }
     94 
     95     static IOVecWrapper get(int size) {
     96         IOVecWrapper wrapper = cached.get();
     97         if (wrapper != null && wrapper.size < size) {
     98             // not big enough; eagerly release memory
     99             wrapper.vecArray.free();
    100             wrapper = null;
    101         }
    102         if (wrapper == null) {
    103             wrapper = new IOVecWrapper(size);
    104             Cleaner.create(wrapper, new Deallocator(wrapper.vecArray));
    105             cached.set(wrapper);
    106         }
    107         return wrapper;
    108     }
    109 
    110     void setBuffer(int i, ByteBuffer buf, int pos, int rem) {
    111         this.buf[i] = buf;
    112         this.position[i] = pos;
    113         this.remaining[i] = rem;
    114     }
    115 
    116     void setShadow(int i, ByteBuffer buf) {
    117         shadow[i] = buf;
    118     }
    119 
    120     ByteBuffer getBuffer(int i) {
    121         return buf[i];
    122     }
    123 
    124     int getPosition(int i) {
    125         return position[i];
    126     }
    127 
    128     int getRemaining(int i) {
    129         return remaining[i];
    130     }
    131 
    132     ByteBuffer getShadow(int i) {
    133         return shadow[i];
    134     }
    135 
    136     void clearRefs(int i) {
    137         buf[i] = null;
    138         shadow[i] = null;
    139     }
    140 
    141     void putBase(int i, long base) {
    142         int offset = SIZE_IOVEC * i + BASE_OFFSET;
    143         if (addressSize == 4)
    144             vecArray.putInt(offset, (int)base);
    145         else
    146             vecArray.putLong(offset, base);
    147     }
    148 
    149     void putLen(int i, long len) {
    150         int offset = SIZE_IOVEC * i + LEN_OFFSET;
    151         if (addressSize == 4)
    152             vecArray.putInt(offset, (int)len);
    153         else
    154             vecArray.putLong(offset, len);
    155     }
    156 
    157     static {
    158         addressSize = Util.unsafe().addressSize();
    159         LEN_OFFSET = addressSize;
    160         SIZE_IOVEC = (short) (addressSize * 2);
    161     }
    162 }
    163