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/* This file is part of indexlib.
* Copyright (C) 2005 Luís Pedro Coelho <luis@luispedro.org>
*
* Indexlib is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License, version 2, as
* published by the Free Software Foundation and available as file
* GPL_V2 which is distributed along with indexlib.
*
* Indexlib 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 for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
* MA 02110-1301, USA
*
* In addition, as a special exception, the copyright holders give
* permission to link the code of this program with any edition of
* the TQt library by Trolltech AS, Norway (or with modified versions
* of TQt that use the same license as TQt), and distribute linked
* combinations including the two. You must obey the GNU General
* Public License in all respects for all of the code used other than
* TQt. If you modify this file, you may extend this exception to
* your version of the file, but you are not obligated to do so. If
* you do not wish to do so, delete this exception statement from
* your version.
*/
#include "mmap_manager.h"
#include "logfile.h"
#include "exception.h"
#include <sys/types.h>
#include <sys/mman.h>
#include <strings.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <unistd.h>
#include <cstring>
#include "format.h"
using indexlib::detail::errno_error;
mmap_manager::mmap_manager( std::string filename )
:filename_( filename ),
pagesize_( ( size_t )sysconf( _SC_PAGESIZE ) ),
base_( 0 ),
size_( 0 )
{
fd_ = open( filename.c_str(), O_RDWR | O_CREAT, 0644 );
logfile() << format( "open( %s, O_RDWR) returned %s\n" ) % filename % fd_;
if ( fd_ > 0 ) {
struct stat st;
if ( fstat( fd_, &st ) == -1 ) {
throw errno_error( "stat()" );
}
if ( st.st_size ) map( st.st_size );
} else {
fd_ = open( filename.c_str(), O_RDWR );
if ( !fd_ ) throw errno_error( "open()" );
}
}
mmap_manager::~mmap_manager()
{
unmap();
close( fd_ );
}
void mmap_manager::resize( unsigned ns ) {
if ( size() >= ns ) return;
unsigned old_size = size();
unmap();
ns = ( ns / pagesize_ + bool( ns % pagesize_ ) ) * pagesize_;
ftruncate( fd_, ns );
map( ns );
logfile() << format( "Going to bzero from %s to %s)\n" ) % old_size % size();
memset( rw_base( old_size ), 0, size() - old_size );
}
void mmap_manager::unmap() {
if ( !base_ ) return;
if ( munmap( base_, size_ ) == -1 ) {
throw errno_error( "munmap()" ); // This should be BUG
}
base_ = 0;
size_ = 0;
}
void mmap_manager::map( unsigned size ) {
base_ = mmap( 0, size, PROT_READ|PROT_WRITE, MAP_SHARED, fd_, 0 );
if ( base_ == reinterpret_cast<void*>( -1 ) ) {
throw errno_error( "mmap()" );
}
size_ = size;
}
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