c4cbde9853
We will need cluster/page aligned access for certain files (indices), this files will contain an initial header describing the contents. A bias is used to step over this header and align the following data.
125 lines
3 KiB
C
125 lines
3 KiB
C
/*
|
|
mmapings.h - manage ranges of mmaped areas on a filedescriptor
|
|
|
|
Copyright (C) Lumiera.org
|
|
2008, Christian Thaeter <ct@pipapo.org>
|
|
|
|
This program is free software; you can redistribute it and/or
|
|
modify it under the terms of the GNU General Public License as
|
|
published by the Free Software Foundation; either version 2 of the
|
|
License, or (at your option) any later version.
|
|
|
|
This program is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
GNU General Public License for more details.
|
|
|
|
You should have received a copy of the GNU General Public License
|
|
along with this program; if not, write to the Free Software
|
|
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
|
|
*/
|
|
|
|
#ifndef LUMIERA_MMAPINGS_H
|
|
#define LUMIERA_MMAPINGS_H
|
|
|
|
#include "lib/mutex.h"
|
|
#include "lib/llist.h"
|
|
|
|
typedef struct lumiera_mmapings_struct lumiera_mmapings;
|
|
typedef lumiera_mmapings* LumieraMMapings;
|
|
|
|
#include "backend/filedescriptor.h"
|
|
#include "backend/mmap.h"
|
|
#include "backend/file.h"
|
|
|
|
#include <nobug.h>
|
|
|
|
//NOBUG_DECLARE_FLAG (mmapings);
|
|
|
|
/**
|
|
* @file
|
|
* Manage the mmap objects of a file
|
|
*
|
|
*/
|
|
|
|
struct lumiera_mmapings_struct
|
|
{
|
|
/** mmaped ranges are kept in an list sorted by the size of the mmaping, might be improved to a tree someday **/
|
|
llist mmaps;
|
|
|
|
/**
|
|
* chunkssize is the smallest granularity which is used for mmapping files, it
|
|
* should reflect the intended file usage, that is 'pagesize' for small or non growing
|
|
* files and some MB for media files. Must be a 2's exponent of pagesize.
|
|
**/
|
|
size_t chunksize;
|
|
|
|
/**
|
|
* bias shifts the chunk begin to suppress headers for example
|
|
**/
|
|
size_t bias;
|
|
|
|
LumieraFiledescriptor descriptor;
|
|
lumiera_mutex lock;
|
|
};
|
|
|
|
/**
|
|
* initialize mmapings container
|
|
*
|
|
*/
|
|
LumieraMMapings
|
|
lumiera_mmapings_init (LumieraMMapings self, LumieraFile file, size_t chunksize, size_t bias);
|
|
|
|
/**
|
|
* destroy mmapings container and free all resources.
|
|
*
|
|
*/
|
|
LumieraMMapings
|
|
lumiera_mmapings_destroy (LumieraMMapings self);
|
|
|
|
/**
|
|
* allocate and initialize new mmapings container
|
|
*
|
|
*/
|
|
LumieraMMapings
|
|
lumiera_mmapings_new (LumieraFile file, size_t chunksize, size_t bias);
|
|
|
|
/**
|
|
* destroy and free mmapings container and all its resources
|
|
*
|
|
*/
|
|
void
|
|
lumiera_mmapings_delete (LumieraMMapings self);
|
|
|
|
|
|
/**
|
|
* acquire a mmap which covers the given range
|
|
* @param self mmapings where to search
|
|
* @param start begin of the required range
|
|
* @param size requested size
|
|
* @return MMap object covering the requested range or NULL on error
|
|
*/
|
|
LumieraMMap
|
|
lumiera_mmapings_mmap_acquire (LumieraMMapings self, LumieraFile file, off_t start, size_t size);
|
|
|
|
|
|
/**
|
|
* release a previously acquired MMap object
|
|
* @param self mmapings to which the map belongs
|
|
* @param acquirer holding node
|
|
* @param map object to be released
|
|
*/
|
|
void
|
|
lumiera_mmapings_release_mmap (LumieraMMapings self, LumieraMMap map);
|
|
|
|
|
|
|
|
|
|
#endif
|
|
/*
|
|
// Local Variables:
|
|
// mode: C
|
|
// c-file-style: "gnu"
|
|
// indent-tabs-mode: nil
|
|
// End:
|
|
*/
|