242 lines
7.1 KiB
C
242 lines
7.1 KiB
C
/* java_nio_MappedByteBufferImpl.c - Native methods for MappedByteBufferImpl
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Copyright (C) 2004, 2005, 2006 Free Software Foundation, Inc.
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This file is part of GNU Classpath.
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GNU Classpath is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GNU Classpath is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GNU Classpath; see the file COPYING. If not, write to the
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Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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02110-1301 USA.
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Linking this library statically or dynamically with other modules is
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making a combined work based on this library. Thus, the terms and
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conditions of the GNU General Public License cover the whole
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combination.
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As a special exception, the copyright holders of this library give you
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permission to link this library with independent modules to produce an
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executable, regardless of the license terms of these independent
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modules, and to copy and distribute the resulting executable under
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terms of your choice, provided that you also meet, for each linked
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independent module, the terms and conditions of the license of that
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module. An independent module is a module which is not derived from
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or based on this library. If you modify this library, you may extend
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this exception to your version of the library, but you are not
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obligated to do so. If you do not wish to do so, delete this
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exception statement from your version. */
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#include <config.h>
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#include <errno.h>
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#include <jni.h>
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#include <jcl.h>
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#include "java_nio_MappedByteBufferImpl.h"
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#include <string.h>
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#include <stdlib.h>
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#ifdef HAVE_UNISTD_H
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#include <unistd.h>
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#endif /* HAVE_UNISTD_H */
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#ifdef HAVE_SYS_MMAN_H
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#include <sys/mman.h>
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#endif /* HAVE_SYS_MMAN_H */
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#define IO_EXCEPTION "java/io/IOException"
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/* FIXME these are defined in gnu_java_nio_channels_FileChannelImpl
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too; should be someplace common. */
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#define ALIGN_DOWN(p,s) ((jpointer)(p) - ((jpointer)(p) % (s)))
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#define ALIGN_UP(p,s) ((jpointer)(p) + ((s) - ((jpointer)(p) % (s))))
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/**
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* Returns the memory page size of this platform.
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*
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* \return The page size.
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*/
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static long
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get_pagesize (void)
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{
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/* FIXME can we just try HAVE_SYSCONF? */
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#if defined(HAVE_GETPAGESIZE)
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return getpagesize ();
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#elif defined (HAVE_SYSCONF)
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return sysconf (_SC_PAGESIZE);
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#endif /* HAVE_GETPAGESIZE / HAVE_SYSCONF */
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}
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/**
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* Retrieve the 'address' and 'cap' (the mapped size) fields of this
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* buffer.
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*
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* This function will align the address down to the nearest page
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* boundary, and the size up to the nearest page boundary. Thus, it is
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* safe to use these values in 'mman' functions.
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*
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* \param env The JNI environment pointer.
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* \param this The MappedByteBufferImpl instance.
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* \param address A pointer to where the actual pointer should be
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* stored.
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* \param size A pointer to where the mapped region's size should be
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* stored
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*/
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static void
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get_raw_values (JNIEnv *env, jobject this, void **address, size_t *size)
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{
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const long pagesize = get_pagesize ();
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jfieldID MappedByteBufferImpl_address;
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jfieldID MappedByteBufferImpl_size;
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jobject MappedByteBufferImpl_address_value = NULL;
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*address = NULL;
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/* 'address' is declared in java.nio.Buffer */
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MappedByteBufferImpl_address
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= (*env)->GetFieldID (env, (*env)->GetObjectClass (env, this),
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"address", "Lgnu/classpath/Pointer;");
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/* 'cap' -- likewise, the capacity */
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MappedByteBufferImpl_size
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= (*env)->GetFieldID (env, (*env)->GetObjectClass (env, this),
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"cap", "I");
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if (MappedByteBufferImpl_address != NULL)
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{
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MappedByteBufferImpl_address_value =
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(*env)->GetObjectField (env, this, MappedByteBufferImpl_address);
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}
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if ((*env)->ExceptionOccurred (env))
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return;
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if (MappedByteBufferImpl_address_value == NULL)
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{
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JCL_ThrowException (env, "java/lang/NullPointerException",
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"mapped address is NULL");
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return;
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}
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*address = (void *)
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ALIGN_DOWN (JCL_GetRawData (env, MappedByteBufferImpl_address_value), pagesize);
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*size = (size_t)
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ALIGN_UP ((*env)->GetIntField (env, this, MappedByteBufferImpl_size),
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pagesize);
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}
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JNIEXPORT void JNICALL
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Java_java_nio_MappedByteBufferImpl_unmapImpl (JNIEnv *env, jobject this)
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{
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#ifdef HAVE_MUNMAP
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void *address;
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size_t size;
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get_raw_values (env, this, &address, &size);
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if (address == NULL)
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return;
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if (munmap (address, size) != 0)
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{
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JCL_ThrowException (env, IO_EXCEPTION, strerror (errno));
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return;
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}
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#else
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JCL_ThrowException (env, IO_EXCEPTION,
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"unmapping files not implemented");
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#endif /* HAVE_MUNMAP */
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}
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JNIEXPORT jboolean JNICALL
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Java_java_nio_MappedByteBufferImpl_isLoadedImpl (JNIEnv * env, jobject this)
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{
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#ifdef HAVE_MINCORE
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void *address;
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size_t size;
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char *vec;
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size_t count, i;
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const long pagesize = get_pagesize ();
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/*
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* FIXME on Darwin this does not work if the mapped region is
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* exactly one page long; i.e., 'mincore' tells us it isn't loaded.
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*/
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get_raw_values (env, this, &address, &size);
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if (address == NULL)
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return JNI_FALSE;
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count = (size_t) ((size + pagesize - 1) / pagesize);
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vec = (char *) malloc (count * sizeof (unsigned char));
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/*
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* Darwin (and BSD?) define argument 3 of 'mincore' to be 'char *',
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* while GNU libc defines it to be 'unsigned char *'. Casting the
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* argument to 'void *' fixes this, but not with C++. So you might
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* be SOL if you compile this with g++ (!) on GNU with -Werror.
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*/
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#ifdef __cplusplus
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if (mincore (address, size, vec) != 0)
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#else
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if (mincore (address, size, (void *) vec) != 0)
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#endif /* __cplusplus */
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{
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free (vec);
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JCL_ThrowException (env, IO_EXCEPTION, strerror (errno));
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return JNI_FALSE;
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}
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for (i = 0; i < count; i++)
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{
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if ((vec[i] & 1) == 0)
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return JNI_FALSE;
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}
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return JNI_TRUE;
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#else
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return JNI_FALSE;
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#endif
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}
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JNIEXPORT void JNICALL
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Java_java_nio_MappedByteBufferImpl_loadImpl (JNIEnv *env, jobject this)
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{
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#ifdef HAVE_MADVISE
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void *address;
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size_t size;
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get_raw_values (env, this, &address, &size);
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if (address == NULL)
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return;
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madvise (address, size, MADV_WILLNEED);
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#else
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JCL_ThrowException (env, IO_EXCEPTION,
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"forcing mapped files into core not implemented");
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#endif /* HAVE_MADVISE */
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}
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JNIEXPORT void JNICALL
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Java_java_nio_MappedByteBufferImpl_forceImpl (JNIEnv *env, jobject this)
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{
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#ifdef HAVE_MSYNC
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void *address;
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size_t size;
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get_raw_values (env, this, &address, &size);
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if (address == NULL)
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return;
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/* FIXME: is using MS_SYNC ok? Should we use MS_INVALIDATE? */
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if (msync (address, size, MS_SYNC) != 0)
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{
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JCL_ThrowException (env, IO_EXCEPTION, strerror (errno));
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}
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#else
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JCL_ThrowException (env, IO_EXCEPTION,
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"forcing mapped files to disk not implemented");
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#endif /* HAVE_MSYNC */
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}
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