147 lines
5 KiB
C
147 lines
5 KiB
C
/*
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* Copyright (c) 2008, Swedish Institute of Computer Science
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the Institute nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* This file is part of the Contiki operating system.
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*
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*/
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/**
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* \addtogroup cfs
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* @{
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*/
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#ifndef CFS_COFFEE_H
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#define CFS_COFFEE_H
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#include "cfs.h"
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/**
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* Instruct Coffee that the access pattern to this file is adapted to
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* flash I/O semantics by design, and Coffee should therefore not
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* invoke its own micro logs when file modifications occur.
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*
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* This semantical I/O setting is useful when implementing flash storage
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* algorithms such as database indices on top of Coffee.
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*
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* \sa cfs_coffee_set_io_semantics()
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*/
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#define CFS_COFFEE_IO_FLASH_AWARE 0x1
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/**
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* Instruct Coffee not to attempt to extend the file upon a request
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* to write past the reserved file size.
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*
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* A case when this is necessary is when the file has a firm size limit,
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* and a safeguard is needed to protect against writes beyond this limit.
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*
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* \sa cfs_coffee_set_io_semantics()
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*/
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#define CFS_COFFEE_IO_FIRM_SIZE 0x2
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/**
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* Instruct Coffee to set unused bytes in the destination buffer to zero.
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* Trailing zeros may cause a wrong file size, this option ensures that
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* the corresponding bytes get set, so Coffee does not read unexpected data.
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*
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* \sa cfs_coffee_set_io_semantics()
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*/
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#define CFS_COFFEE_IO_ENSURE_READ_LENGTH 0x4
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/**
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* \file
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* Header for the Coffee file system.
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* \author
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* Nicolas Tsiftes <nvt@sics.se>
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*
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* \name Functions called from application programs
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* @{
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*/
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/**
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* \brief Reserve space for a file.
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* \param name The file name.
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* \param size The initial size to be reserved for the file.
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* \return 0 on success, -1 on failure.
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*
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* Coffee uses sequential page structures for files. The sequential
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* structure can be reserved with a certain size. If a file has not
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* been reserved when it is opened for the first time, it will be
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* allocated with a default size.
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*/
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int cfs_coffee_reserve(const char *name, cfs_offset_t size);
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/**
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* \brief Configure the on-demand log file.
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* \param file The file name.
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* \param log_size The total log file size.
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* \param log_entry_size The log entry size.
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* \return 0 on success, -1 on failure.
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*
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* When file data is first modified, Coffee creates a micro log for the
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* file. The micro log stores a table of modifications whose parameters --
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* the log size and the log entry size -- can be modified through the
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* cfs_coffee_configure_log function.
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*/
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int cfs_coffee_configure_log(const char *file, unsigned log_size,
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unsigned log_entry_size);
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/**
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* \brief Set the I/O semantics for accessing a file.
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*
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* \param fd The file descriptor through which the file is accessed.
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* \param flags A bit vector of flags.
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*
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* Coffee is used on a wide range of storage types, and the default
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* I/O file semantics may not be optimal for the access pattern
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* of a certain file. Hence, this function allows programmers to
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* switch the I/O semantics on a file that is accessed through a
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* particular file descriptor.
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*
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*/
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int cfs_coffee_set_io_semantics(int fd, unsigned flags);
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/**
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* \brief Format the storage area assigned to Coffee.
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* \return 0 on success, -1 on failure.
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*
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* Coffee formats the underlying storage by setting all bits to zero.
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* Formatting must be done before using Coffee for the first time in
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* a mote.
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*
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* Notice that the erased bits may be set to 1 on the physical storage
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* when using flash memory. In this case, Coffee requires that the
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* COFFEE_READ and COFFEE_WRITE functions used to access the flash memory
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* invert all bits.
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*/
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int cfs_coffee_format(void);
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/** @} */
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/** @} */
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#endif /* !COFFEE_H */
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