cdesktopenv/cde/programs/dtmail/libDtMail/Common/BigMalloc.C

129 lines
3.0 KiB
C

/*
* CDE - Common Desktop Environment
*
* Copyright (c) 1993-2012, The Open Group. All rights reserved.
*
* These libraries and programs are free software; you can
* redistribute them and/or modify them under the terms of the GNU
* Lesser General Public License as published by the Free Software
* Foundation; either version 2 of the License, or (at your option)
* any later version.
*
* These libraries and programs are distributed in the hope that
* they will be useful, but WITHOUT ANY WARRANTY; without even the
* implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
* PURPOSE. See the GNU Lesser General Public License for more
* details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with these librararies and programs; if not, write
* to the Free Software Foundation, Inc., 51 Franklin Street, Fifth
* Floor, Boston, MA 02110-1301 USA
*/
/*
*+SNOTICE
*
*
* $XConsortium: BigMalloc.C /main/4 1996/04/21 19:47:03 drk $
*
* RESTRICTED CONFIDENTIAL INFORMATION:
*
* The information in this document is subject to special
* restrictions in a confidential disclosure agreement bertween
* HP, IBM, Sun, USL, SCO and Univel. Do not distribute this
* document outside HP, IBM, Sun, USL, SCO, or Univel wihtout
* Sun's specific written approval. This documment and all copies
* and derivative works thereof must be returned or destroyed at
* Sun's request.
*
* Copyright 1993 Sun Microsystems, Inc. All rights reserved.
*
*+ENOTICE
*/
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <stdlib.h>
#include <fcntl.h>
#if defined(NEED_MMAP_WRAPPER)
extern "C" {
#endif
#include <sys/mman.h>
#if defined(NEED_MMAP_WRAPPER)
}
#endif
#include "BigMalloc.hh"
BigMalloc::BigMalloc(unsigned int size)
{
_size = size;
#if defined(MMAP_NORESERVE)
_fd = open("/dev/zero", O_RDONLY);
_buffer = mmap(NULL, size * 4, (PROT_READ | PROT_WRITE),
MAP_PRIVATE | MAP_NORESERVE, _fd, 0);
#else
_buffer = malloc(size);
#endif
}
BigMalloc::~BigMalloc(void)
{
#if defined(MAP_NORESERVE)
if (_buffer) {
munmap((char *)_buffer, _size * 4);
}
if (_fd >= 0) {
close(_fd);
}
#else
free(_buffer);
#endif
}
void
BigMalloc::Realloc(unsigned int size)
{
#if defined(MAP_NORESERVE)
if (size < (_size * 4)) {
return;
}
unsigned int additional = (size * 4) - (_size * 4);
char * new_buf;
new_buf = mmap(((char *)_buffer) + (_size * 4), additional,
(PROT_READ | PROT_WRITE),
MAP_FIXED | MAP_PRIVATE | MAP_NORESERVE, _fd, (_size * 4));
if (new_buf == (char *)-1) {
// Fixed mapping failed. We will have to map a new region and copy.
//
new_buf = mmap(NULL, size * 4, (PROT_READ | PROT_WRITE),
MAP_PRIVATE | MAP_NORESERVE, _fd, 0);
memcpy(new_buf, _buffer, _size * 4);
munmap((char *)_buffer, _size * 4);
}
_buffer = new_buf;
_size = size;
#else
_size = size;
_buffer = realloc(_buffer, _size);
#endif
}
BigMalloc::operator char*(void)
{
return((char *)_buffer);
}