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package sun.nio.ch;

import java.nio.ByteBuffer;
import jdk.internal.ref.CleanerFactory;


Manipulates a native array of iovec structs on Solaris:
 
typedef struct iovec {
    caddr_t  iov_base;
    int      iov_len;
 } iovec_t;
Author:Mike McCloskey
Since:1.4
/** * Manipulates a native array of iovec structs on Solaris: * * <pre> {@code * typedef struct iovec { * caddr_t iov_base; * int iov_len; * } iovec_t; * }</pre> * * @author Mike McCloskey * @since 1.4 */
class IOVecWrapper { // Miscellaneous constants private static final int BASE_OFFSET = 0; private static final int LEN_OFFSET; private static final int SIZE_IOVEC; // The iovec array private final AllocatedNativeObject vecArray; // Number of elements in iovec array private final int size; // Buffers and position/remaining corresponding to elements in iovec array private final ByteBuffer[] buf; private final int[] position; private final int[] remaining; // Shadow buffers for cases when original buffer is substituted private final ByteBuffer[] shadow; // Base address of this array final long address; // Address size in bytes static int addressSize; private static class Deallocator implements Runnable { private final AllocatedNativeObject obj; Deallocator(AllocatedNativeObject obj) { this.obj = obj; } public void run() { obj.free(); } } // per thread IOVecWrapper private static final ThreadLocal<IOVecWrapper> cached = new ThreadLocal<IOVecWrapper>(); private IOVecWrapper(int size) { this.size = size; this.buf = new ByteBuffer[size]; this.position = new int[size]; this.remaining = new int[size]; this.shadow = new ByteBuffer[size]; this.vecArray = new AllocatedNativeObject(size * SIZE_IOVEC, false); this.address = vecArray.address(); } static IOVecWrapper get(int size) { IOVecWrapper wrapper = cached.get(); if (wrapper != null && wrapper.size < size) { // not big enough; eagerly release memory wrapper.vecArray.free(); wrapper = null; } if (wrapper == null) { wrapper = new IOVecWrapper(size); CleanerFactory.cleaner().register(wrapper, new Deallocator(wrapper.vecArray)); cached.set(wrapper); } return wrapper; } void setBuffer(int i, ByteBuffer buf, int pos, int rem) { this.buf[i] = buf; this.position[i] = pos; this.remaining[i] = rem; } void setShadow(int i, ByteBuffer buf) { shadow[i] = buf; } ByteBuffer getBuffer(int i) { return buf[i]; } int getPosition(int i) { return position[i]; } int getRemaining(int i) { return remaining[i]; } ByteBuffer getShadow(int i) { return shadow[i]; } void clearRefs(int i) { buf[i] = null; shadow[i] = null; } void putBase(int i, long base) { int offset = SIZE_IOVEC * i + BASE_OFFSET; if (addressSize == 4) vecArray.putInt(offset, (int)base); else vecArray.putLong(offset, base); } void putLen(int i, long len) { int offset = SIZE_IOVEC * i + LEN_OFFSET; if (addressSize == 4) vecArray.putInt(offset, (int)len); else vecArray.putLong(offset, len); } static { addressSize = Util.unsafe().addressSize(); LEN_OFFSET = addressSize; SIZE_IOVEC = (short) (addressSize * 2); } }