contiki/examples/sky/example-coffee.c

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/*
* Copyright (c) 2011, 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.
*/
/**
* \file
* Example on how to use CFS/Coffee.
* \author
* Nicolas Tsiftes <nvt@sics.se>
*/
#include <stdio.h>
#include "contiki.h"
#include "cfs/cfs.h"
#include "cfs/cfs-coffee.h"
PROCESS(example_coffee_process, "Coffee example");
AUTOSTART_PROCESSES(&example_coffee_process);
#define FILENAME "test"
/* Formatting is needed if the storage device is in an unknown state;
e.g., when using Coffee on the storage device for the first time. */
#ifndef NEED_FORMATTING
#define NEED_FORMATTING 0
#endif
static int
file_test(const char *filename, char *msg)
{
static uint8_t sequence;
int fd;
int r;
struct record {
char message[16];
uint8_t sequence;
} record;
/*
* Coffee determines the file length by finding the last non-zero byte
* of the file. This I/O semantic requires that each record should end
* with a non-zero, if we are writing multiple records and closing the
* file descriptor in between.
*
* In this example, in which the file_test function can be called
* multiple times, we ensure that the sequence counter starts at 1.
*/
if(sequence == 255) {
/* No more sequence numbers available. */
return -1;
}
sequence++;
strncpy(record.message, msg, sizeof(record.message) - 1);
record.message[sizeof(record.message) - 1] = '\0';
record.sequence = sequence;
/* Obtain a file descriptor for the file, capable of handling both
reads and writes. */
fd = cfs_open(FILENAME, CFS_WRITE | CFS_APPEND | CFS_READ);
if(fd < 0) {
printf("failed to open %s\n", FILENAME);
return 0;
}
r = cfs_write(fd, &record, sizeof(record));
if(r != sizeof(record)) {
printf("failed to write %d bytes to %s\n",
(int)sizeof(record), FILENAME);
cfs_close(fd);
return 0;
}
printf("Wrote message \"%s\", sequence %u\n",
record.message, record.sequence);
/* To read back the message, we need to move the file pointer to the
beginning of the file. */
if(cfs_seek(fd, 0, CFS_SEEK_SET) != 0) {
printf("seek failed\n");
cfs_close(fd);
return 0;
}
/* Read all written records and print their contents. */
for(;;) {
r = cfs_read(fd, &record, sizeof(record));
if(r == 0) {
break;
} else if(r < sizeof(record)) {
printf("failed to read %d bytes from %s, got %d\n",
(int)sizeof(record), FILENAME, r);
cfs_close(fd);
return 0;
}
printf("Read message \"%s\", sequence %u\n",
record.message, record.sequence);
}
/* Release the internal resources held by Coffee for
the file descriptor. */
cfs_close(fd);
return 1;
}
static int
dir_test(void)
{
struct cfs_dir dir;
struct cfs_dirent dirent;
/* Coffee provides a root directory only. */
if(cfs_opendir(&dir, "/") != 0) {
printf("failed to open the root directory\n");
return 0;
}
/* List all files and their file sizes. */
printf("Available files\n");
while(cfs_readdir(&dir, &dirent) == 0) {
printf("%s (%lu bytes)\n", dirent.name, (unsigned long)dirent.size);
}
cfs_closedir(&dir);
return 1;
}
PROCESS_THREAD(example_coffee_process, ev, data)
{
PROCESS_BEGIN();
#if NEED_FORMATTING
cfs_coffee_format();
#endif
/* Ensure that we will be working with a new file. */
cfs_remove(FILENAME);
if(file_test(FILENAME, "The first test") == 0) {
printf("file test 1 failed\n");
}
if(file_test(FILENAME, "The second test") == 0) {
printf("file test 2 failed\n");
}
if(dir_test() == 0) {
printf("dir test failed\n");
}
PROCESS_END();
}