74 lines
1.9 KiB
C++
74 lines
1.9 KiB
C++
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// include/MappedFile.hh
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// This file is part of libpbe; see http://svn.chezphil.org/libpbe/
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// (C) 2007 Philip Endecott
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// This program 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 of the License, or
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// any later version.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program; if not, write to the Free Software
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// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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#ifndef libpbe_MappedFile_hh
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#define libpbe_MappedFile_hh
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#include "FileDescriptor.hh"
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#include "Exception.hh"
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#include <sys/mman.h>
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namespace pbe {
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class MappedFile {
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public:
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const size_t length;
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const off_t offset;
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char* const addr;
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MappedFile(pbe::FileDescriptor& fd, size_t length_, pbe::FileDescriptor::open_mode_t open_mode,
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off_t offset_ = 0, bool copy_on_write = false):
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length(length_), offset(offset_),
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addr(reinterpret_cast<char*>(fd.mmap(length,open_mode,offset,copy_on_write)))
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{}
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~MappedFile() {
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int rc = munmap(addr,length);
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if (rc==-1) {
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pbe::throw_ErrnoException("munmap()");
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}
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}
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operator char* () const { return addr; }
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template <typename T>
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T* ptr(int offset) const {
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return reinterpret_cast<T*>(reinterpret_cast<char*>(addr)+offset);
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}
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template <typename T>
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T& ref(int offset) const {
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return *ptr<T>(offset);
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}
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void sync() {
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int rc = ::msync(addr,length,MS_SYNC|MS_INVALIDATE);
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if (rc==-1) {
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throw_ErrnoException("msync()");
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}
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}
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};
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};
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#endif
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