nes-proj/backyard/platform/c64/loader/c64-fs-write.c

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/**
* \addtogroup c64fs
* @{
*/
/**
* \file
* Implementation of C64 file writes.
* \author Adam Dunkels <adam@dunkels.com>
*
* The functions in this file are not included in the core Contiki
* code, but must be explicitly linked by an application that that
* wishes to be able to write to files.
*/
/*
* Copyright (c) 2003, Adam Dunkels.
* 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. The name of the author may not be used to endorse or promote
* products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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 desktop environment
*
* $Id: c64-fs-write.c,v 1.1 2007/05/23 23:11:28 oliverschmidt Exp $
*
*/
#include "c64-dio.h"
#include "c64-fs.h"
#include <string.h>
/* An *UGLY* implementation of c64_fs_write that only can be used to
overwrite a single block file. */
extern unsigned char _c64_fs_filebuf[256];
extern unsigned char _c64_fs_filebuftrack,
_c64_fs_filebufsect;
/*-----------------------------------------------------------------------------------*/
/**
* Write data to an open file.
*
* \note This function currently does not support writing to other than a single block file (cannot be more than 254 bytes long).
*
* \param f A pointer to a file descriptor previously opened with c64_fs_open().
*
* \param buf A pointer to a buffer with data that should be written
* to the file.
*
* \param len The length of the data that should be written.
*
* \return The number of bytes actually written.
*
*/
/*-----------------------------------------------------------------------------------*/
int __fastcall__
c64_fs_write(register struct c64_fs_file *f, char *buf, int len)
{
int i;
if(len <= 0) {
return 0;
}
/* Check if current block is already in buffer, and if not read it
from disk. */
if(_c64_fs_filebuftrack != f->track ||
_c64_fs_filebufsect != f->sect) {
_c64_fs_filebuftrack = f->track;
_c64_fs_filebufsect = f->sect;
c64_dio_read_block(_c64_fs_filebuftrack,
_c64_fs_filebufsect,
_c64_fs_filebuf);
}
i = 256 - f->ptr;
if(len < i) {
i = len;
}
memcpy(&_c64_fs_filebuf[f->ptr], buf, i);
f->ptr += i;
if(_c64_fs_filebuf[0] == 0 &&
f->ptr > _c64_fs_filebuf[1]) {
_c64_fs_filebuf[1] = f->ptr;
}
c64_dio_write_block(_c64_fs_filebuftrack,
_c64_fs_filebufsect,
_c64_fs_filebuf);
return i;
}
/*-----------------------------------------------------------------------------------*/
/** @} */