pios_fileout.c

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/*
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
 * for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, see <http://www.gnu.org/licenses/>
 *
 * Additional note on redistribution: The copyright and license notices above
 * must be maintained in each individual source file that is a derivative work
 * of this source file; otherwise redistribution is prohibited.
 */


/* Project Includes */
#include "pios.h"

#include <pios_fileout_priv.h>
#include "pios_thread.h"
#include <unistd.h>
#include <sys/types.h>
#include <errno.h>
#include <fcntl.h>

/* Provide a COM driver */
static void PIOS_FILEOUT_RegisterTxCallback(uintptr_t udp_id, pios_com_callback tx_out_cb, uintptr_t context);
static void PIOS_FILEOUT_TxStart(uintptr_t udp_id, uint16_t tx_bytes_avail);

const struct pios_com_driver pios_fileout_com_driver = {
        .tx_start   = PIOS_FILEOUT_TxStart,
        .bind_tx_cb = PIOS_FILEOUT_RegisterTxCallback,
};


static pios_fileout_dev * find_file_dev_by_id(uintptr_t tcp)
{
        return (pios_fileout_dev *) tcp;
}

int32_t PIOS_FILEOUT_Init(uintptr_t *file_id, const char *filename,
                const char *mode)
{
        pios_fileout_dev *file_dev = PIOS_malloc(sizeof(pios_fileout_dev));

        memset(file_dev, 0, sizeof(*file_dev));

        file_dev->fh = fopen(filename, mode);

        if (!file_dev->fh) {
                perror("fopen");
                return -1;
        }

        setbuf(file_dev->fh, NULL);

        *file_id = (uintptr_t) file_dev;
        
        return 0;
}

static void PIOS_FILEOUT_TxStart(uintptr_t file_id, uint16_t tx_bytes_avail)
{
        pios_fileout_dev *file_dev = find_file_dev_by_id(file_id);
        
        PIOS_Assert(file_dev);
        
        int32_t length,rem;
        
        if (file_dev->tx_out_cb) {
                while (tx_bytes_avail > 0) {
                        bool tx_need_yield = false;
                        length = (file_dev->tx_out_cb)(file_dev->tx_out_context, file_dev->tx_buffer, PIOS_FILEOUT_TX_BUFFER_SIZE, NULL, &tx_need_yield);
                        rem = length;
                        while (rem > 0) {
                                ssize_t len = 0;
                                len = fwrite(file_dev->tx_buffer, 1, length, file_dev->fh);

                                if (len <= 0) {
                                        rem = 0;
                                } else {
                                        rem -= len;
                                }
                        }
                        tx_bytes_avail -= length;
                }
        }
}

static void PIOS_FILEOUT_RegisterTxCallback(uintptr_t file_id, pios_com_callback tx_out_cb, uintptr_t context)
{
        pios_fileout_dev *file_dev = find_file_dev_by_id(file_id);
        
        PIOS_Assert(file_dev);
        
        /*
         * Order is important in these assignments since ISR uses _cb
         * field to determine if it's ok to dereference _cb and _context
         */
        file_dev->tx_out_context = context;
        file_dev->tx_out_cb = tx_out_cb;
}