107 lines
2.1 KiB
C
107 lines
2.1 KiB
C
/*
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*+SNOTICE
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*
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*
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* $XConsortium: BigMalloc.C /main/4 1996/04/21 19:47:03 drk $
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*
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* RESTRICTED CONFIDENTIAL INFORMATION:
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*
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* The information in this document is subject to special
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* restrictions in a confidential disclosure agreement bertween
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* HP, IBM, Sun, USL, SCO and Univel. Do not distribute this
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* document outside HP, IBM, Sun, USL, SCO, or Univel wihtout
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* Sun's specific written approval. This documment and all copies
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* and derivative works thereof must be returned or destroyed at
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* Sun's request.
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*
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* Copyright 1993 Sun Microsystems, Inc. All rights reserved.
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*
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*+ENOTICE
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*/
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#include <stdio.h>
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#include <string.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <fcntl.h>
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#if defined(NEED_MMAP_WRAPPER)
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extern "C" {
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#endif
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#include <sys/mman.h>
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#if defined(NEED_MMAP_WRAPPER)
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}
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#endif
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#include "BigMalloc.hh"
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BigMalloc::BigMalloc(unsigned int size)
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{
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_size = size;
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#if defined(MMAP_NORESERVE)
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_fd = open("/dev/zero", O_RDONLY);
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_buffer = mmap(NULL, size * 4, (PROT_READ | PROT_WRITE),
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MAP_PRIVATE | MAP_NORESERVE, _fd, 0);
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#else
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_buffer = malloc(size);
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#endif
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}
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BigMalloc::~BigMalloc(void)
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{
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#if defined(MAP_NORESERVE)
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if (_buffer) {
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munmap((char *)_buffer, _size * 4);
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}
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if (_fd >= 0) {
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close(_fd);
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}
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#else
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free(_buffer);
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#endif
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}
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void
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BigMalloc::Realloc(unsigned int size)
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{
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#if defined(MAP_NORESERVE)
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if (size < (_size * 4)) {
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return;
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}
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unsigned int additional = (size * 4) - (_size * 4);
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char * new_buf;
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new_buf = mmap(((char *)_buffer) + (_size * 4), additional,
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(PROT_READ | PROT_WRITE),
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MAP_FIXED | MAP_PRIVATE | MAP_NORESERVE, _fd, (_size * 4));
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if (new_buf == (char *)-1) {
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// Fixed mapping failed. We will have to map a new region and copy.
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//
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new_buf = mmap(NULL, size * 4, (PROT_READ | PROT_WRITE),
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MAP_PRIVATE | MAP_NORESERVE, _fd, 0);
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memcpy(new_buf, _buffer, _size * 4);
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munmap((char *)_buffer, _size * 4);
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}
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_buffer = new_buf;
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_size = size;
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#else
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_size = size;
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_buffer = realloc(_buffer, _size);
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#endif
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}
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BigMalloc::operator char*(void)
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{
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return((char *)_buffer);
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}
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