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/*
* Copyright (c) 2008, 2013, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code 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
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package sun.nio.ch;
import java.io.IOException;
import sun.misc.Unsafe;
/**
* Provides access to the Linux epoll facility.
*/
class EPoll {
private EPoll() { }
private static final Unsafe unsafe = Unsafe.getUnsafe();
/**
* typedef union epoll_data {
* void *ptr;
* int fd;
* __uint32_t u32;
* __uint64_t u64;
* } epoll_data_t;
*
* struct epoll_event {
* __uint32_t events;
* epoll_data_t data;
* }
*/
private static final int SIZEOF_EPOLLEVENT = eventSize();
private static final int OFFSETOF_EVENTS = eventsOffset();
private static final int OFFSETOF_FD = dataOffset();
// opcodes
static final int EPOLL_CTL_ADD = 1;
static final int EPOLL_CTL_DEL = 2;
static final int EPOLL_CTL_MOD = 3;
// flags
static final int EPOLLONESHOT = (1 << 30);
/**
* Allocates a poll array to handle up to {@code count} events.
*/
static long allocatePollArray(int count) {
return unsafe.allocateMemory(count * SIZEOF_EPOLLEVENT);
}
/**
* Free a poll array
*/
static void freePollArray(long address) {
unsafe.freeMemory(address);
}
/**
* Returns event[i];
*/
static long getEvent(long address, int i) {
return address + (SIZEOF_EPOLLEVENT*i);
}
/**
* Returns event->data.fd
*/
static int getDescriptor(long eventAddress) {
return unsafe.getInt(eventAddress + OFFSETOF_FD);
}
/**
* Returns event->events
*/
static int getEvents(long eventAddress) {
return unsafe.getInt(eventAddress + OFFSETOF_EVENTS);
}
// -- Native methods --
private static native int eventSize();
private static native int eventsOffset();
private static native int dataOffset();
static native int epollCreate() throws IOException;
static native int epollCtl(int epfd, int opcode, int fd, int events);
static native int epollWait(int epfd, long pollAddress, int numfds)
throws IOException;
// Android-removed: Code to load native libraries, doesn't make sense on Android.
/*
static {
IOUtil.load();
}
*/
}
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