osd-contiki/core/cfs/cfs-ram.c

165 lines
4.4 KiB
C

/*
* 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>
*
*/
#include <string.h>
#include "cfs/cfs.h"
struct filestate {
int flag;
#define FLAG_FILE_CLOSED 0
#define FLAG_FILE_OPEN 1
int fileptr;
int filesize;
};
#ifdef CFS_RAM_CONF_SIZE
#define CFS_RAM_SIZE CFS_RAM_CONF_SIZE
#else
#define CFS_RAM_SIZE 4096
#endif
static struct filestate file;
static char filemem[CFS_RAM_SIZE];
/*---------------------------------------------------------------------------*/
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;
}
}
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)
{
if(file.fileptr + len > sizeof(filemem)) {
len = sizeof(filemem) - file.fileptr;
}
if(file.fileptr + len > file.filesize) {
len = file.filesize - file.fileptr;
}
if(f == 1) {
memcpy(buf, &filemem[file.fileptr], len);
file.fileptr += len;
return len;
} else {
return -1;
}
}
/*---------------------------------------------------------------------------*/
int
cfs_write(int f, const void *buf, unsigned int len)
{
if(file.fileptr >= sizeof(filemem)) {
return 0;
}
if(file.fileptr + len > sizeof(filemem)) {
len = sizeof(filemem) - file.fileptr;
}
if(file.fileptr + len > file.filesize) {
/* Extend the size of the file. */
file.filesize = file.fileptr + len;
}
if(f == 1) {
memcpy(&filemem[file.fileptr], buf, len);
file.fileptr += len;
return len;
} else {
return -1;
}
}
/*---------------------------------------------------------------------------*/
cfs_offset_t
cfs_seek(int f, cfs_offset_t o, int w)
{
if(w == CFS_SEEK_SET && f == 1) {
if(o > file.filesize) {
o = file.filesize;
}
file.fileptr = o;
return o;
}
return (cfs_offset_t)-1;
}
/*---------------------------------------------------------------------------*/
int
cfs_remove(const char *name)
{
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)
{
}
/*---------------------------------------------------------------------------*/