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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
* This file is part of the LibreOffice project.
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
*
* This file incorporates work covered by the following license notice:
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed
* with this work for additional information regarding copyright
* ownership. The ASF licenses this file to you under the Apache
* License, Version 2.0 (the "License"); you may not use this file
* except in compliance with the License. You may obtain a copy of
* the License at http://www.apache.org/licenses/LICENSE-2.0 .
*/
#include "file_image.h"
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <string.h>
/*
* file_image_open
*/
int file_image_open (file_image * image, const char * filename)
{
int result = 0;
int fd;
struct stat st;
void * p;
if (image == NULL)
return EINVAL;
image->m_base = MAP_FAILED;
image->m_size = 0;
if ((fd = open (filename, O_RDONLY)) == -1)
return errno;
if (fstat (fd, &st) == -1)
{
result = errno;
goto cleanup_and_leave;
}
p = mmap (NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
if (p == MAP_FAILED)
{
result = errno;
goto cleanup_and_leave;
}
image->m_base = p;
image->m_size = st.st_size;
cleanup_and_leave:
close (fd);
return result;
}
/*
* file_image_pagein.
*/
int file_image_pagein (file_image * image)
{
long s = -1;
volatile char c =0;
size_t idx;
if (image == NULL)
return EINVAL;
if (image->m_base == NULL)
return EINVAL;
if (image->m_size == 0)
return 0;
if (madvise (image->m_base, image->m_size, MADV_WILLNEED) == -1)
return errno;
s = sysconf (_SC_PAGESIZE);
if (s == -1)
s = 0x1000;
// force touching of each page despite the optimizer
for(idx = 0; idx < image->m_size; idx += (size_t)s)
{
c ^= ((volatile const char*)(image->m_base))[idx];
}
c ^= ((volatile const char*)(image->m_base))[image->m_size-1];
(void)c; // silence Clang 13 trunk -Wunused-but-set-variable
return 0;
}
/*
* file_image_close
*/
int file_image_close (file_image * image)
{
if (image == NULL)
return EINVAL;
if (munmap (image->m_base, image->m_size) == -1)
return errno;
image->m_base = NULL;
image->m_size = 0;
return 0;
}
/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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