mirror of https://github.com/vitalif/zbackup
67 lines
1.9 KiB
C++
67 lines
1.9 KiB
C++
// Copyright (c) 2012-2014 Konstantin Isakov <ikm@zbackup.org> and ZBackup contributors, see CONTRIBUTORS
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// Part of ZBackup. Licensed under GNU GPLv2 or later + OpenSSL, see LICENSE
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#ifndef UNBUFFERED_FILE_HH_INCLUDED
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#define UNBUFFERED_FILE_HH_INCLUDED
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#include <stddef.h>
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#include <stdint.h>
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#include <sys/types.h>
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#include <exception>
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#include "ex.hh"
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#include "nocopy.hh"
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/// A file which does not employ its own buffering.
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/// TODO: add support for memory-mapped I/O, with the interface which would look
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/// like that of a zero-copy stream. However, since we can do encryption in-
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/// place, both interfaces should be available - when there's no memory-mapped
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/// I/O available, the user should still provide its own buffer (and then do
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/// in-place encryption in it).
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class UnbufferedFile: NoCopy
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{
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public:
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DEF_EX( Ex, "Unbuffered file exception", std::exception )
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DEF_EX_STR( exCantOpen, "Can't open file", Ex )
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DEF_EX( exReadError, "File read error", Ex )
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DEF_EX( exWriteError, "File write error", Ex )
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DEF_EX( exSeekError, "File seek error", Ex )
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enum Mode
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{
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ReadOnly,
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WriteOnly,
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ReadWrite
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};
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typedef int64_t Offset;
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/// Opens the given file
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UnbufferedFile( char const * fileName, Mode ) throw( exCantOpen );
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/// Reads up to 'size' bytes into the buffer. Returns the number of bytes
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/// read. If the value returned is less than the 'size' provided, the end of
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/// file was reached
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size_t read( void * buf, size_t size ) throw( exReadError );
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/// Writes 'size' bytes
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void write( void const * buf, size_t size ) throw( exWriteError );
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/// Returns file size
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Offset size() throw( exSeekError );
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/// Seeks to the given offset, relative to the current file offset
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void seekCur( Offset ) throw( exSeekError );
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/// Seeks to the given offset, relative to the beginning
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void seek( Offset ) throw( exSeekError );
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~UnbufferedFile() throw();
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private:
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int fd;
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};
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#endif
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