contiki/core/cfs/cfs-xmem.c

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/*
* Copyright (c) 2004, Swedish Institute of Computer Science.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* This file is part of the Contiki operating system.
*
* Author: Adam Dunkels <adam@sics.se>
*
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* $Id: cfs-xmem.c,v 1.8 2008/01/24 13:08:35 adamdunkels Exp $
*/
#include "cfs/cfs.h"
#include "dev/xmem.h"
struct filestate {
int flag;
#define FLAG_FILE_CLOSED 0
#define FLAG_FILE_OPEN 1
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unsigned int fileptr;
unsigned int filesize;
};
#ifdef CFS_XMEM_CONF_OFFSET
#define CFS_XMEM_OFFSET CFS_XMEM_CONF_OFFSET
#else
#define CFS_XMEM_OFFSET 0
#endif
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/* Note the CFS_XMEM_CONF_SIZE must be a tuple of XMEM_ERASE_UNIT_SIZE */
#ifdef CFS_XMEM_CONF_SIZE
#define CFS_XMEM_SIZE CFS_XMEM_CONF_SIZE
#else
#define CFS_XMEM_SIZE XMEM_ERASE_UNIT_SIZE
#endif
static struct filestate file;
/*---------------------------------------------------------------------------*/
int
cfs_open(const char *n, int f)
{
if(file.flag == FLAG_FILE_CLOSED) {
file.flag = FLAG_FILE_OPEN;
if(f & CFS_READ) {
file.fileptr = 0;
}
if(f & CFS_WRITE){
if(f & CFS_APPEND) {
file.fileptr = file.filesize;
} else {
file.fileptr = 0;
file.filesize = 0;
xmem_erase(CFS_XMEM_SIZE, CFS_XMEM_OFFSET);
}
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}
return 1;
} else {
return -1;
}
}
/*---------------------------------------------------------------------------*/
void
cfs_close(int f)
{
file.flag = FLAG_FILE_CLOSED;
}
/*---------------------------------------------------------------------------*/
int
cfs_read(int f, void *buf, unsigned int len)
{
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if(file.fileptr + len > CFS_XMEM_SIZE) {
len = CFS_XMEM_SIZE - file.fileptr;
}
if(file.fileptr + len > file.filesize) {
len = file.filesize - file.fileptr;
}
if(f == 1) {
xmem_pread(buf, len, CFS_XMEM_OFFSET + file.fileptr);
file.fileptr += len;
return len;
} else {
return -1;
}
}
/*---------------------------------------------------------------------------*/
int
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cfs_write(int f, const void *buf, unsigned int len)
{
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if(file.fileptr >= CFS_XMEM_SIZE) {
return 0;
}
if(file.fileptr + len > CFS_XMEM_SIZE) {
len = CFS_XMEM_SIZE - file.fileptr;
}
if(file.fileptr + len > file.filesize) {
/* Extend the size of the file. */
file.filesize = file.fileptr + len;
}
if(f == 1) {
xmem_pwrite(buf, len, CFS_XMEM_OFFSET + file.fileptr);
file.fileptr += len;
return len;
} else {
return -1;
}
}
/*---------------------------------------------------------------------------*/
unsigned int
cfs_seek(int f, unsigned int o)
{
if(f == 1) {
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if(o > file.filesize) {
o = file.filesize;
}
file.fileptr = o;
return o;
} else {
return -1;
}
}
/*---------------------------------------------------------------------------*/
int
cfs_opendir(struct cfs_dir *p, const char *n)
{
return -1;
}
/*---------------------------------------------------------------------------*/
int
cfs_readdir(struct cfs_dir *p, struct cfs_dirent *e)
{
return -1;
}
/*---------------------------------------------------------------------------*/
void
cfs_closedir(struct cfs_dir *p)
{
}
/*---------------------------------------------------------------------------*/