root/trunk/bertos/kern/kfile.h @ 1798

/**
 * \file
 * <!--
 * This file is part of BeRTOS.
 *
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 * it under the terms of the GNU General Public License as published by
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 * (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, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * As a special exception, you may use this file as part of a free software
 * library without restriction.  Specifically, if other files instantiate
 * templates or use macros or inline functions from this file, or you compile
 * this file and link it with other files to produce an executable, this
 * file does not by itself cause the resulting executable to be covered by
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 * invalidate any other reasons why the executable file might be covered by
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 *
 * Copyright 2004 Develer S.r.l. (http://www.develer.com/)
 * Copyright 1999, 2000, 2001, 2003 Bernie Innocenti <bernie@codewiz.org>
 *
 * -->
 *
 * \brief Virtual KFile I/O interface.
 *
 * KFile is a simple, generic interface for file I/O.  It uses an
 * object-oriented model to supply a device-neutral interface to
 * communicate with drivers.
 *
 * This module contains only definitions, the instance structure
 * and the common API.
 * Each KFile subclass can override one or more methods of the interface,
 * and can extend the base KFile structure with its own private data.
 * For instance, a serial driver might implement the KFile interface by
 * declaring a context structure like this:
 *
 * \code
 * typedef struct Serial
 * {
 *      // base class instance
 *      KFile fd;
 *
 *      // private instance data
 *      FIFOBuffer txfifo, rxfifo;
 * } Serial;
 * \endcode
 *
 * You should also supply a macro for casting KFile to Serial:
 *
 * \code
 * INLINE Serial * SERIAL_CAST(KFile *fd)
 * {
 *              ASSERT(fd->_type == KFT_SERIAL);
 *              return (Serial *)fd;
 * }
 * \endcode
 *
 * Then you can implement as many interface functions as needed
 * and leave the rest to NULL.
 *
 * Example implementation of the close KFile method for Serial:
 *
 * \code
 * static int ser_kfile_close(struct KFile *fd)
 * {
 *              Serial *fds = SERIAL_CAST(fd);
 *      // [driver specific code here]
 *              return 0;
 * }
 * \endcode
 *
 * The SERIAL_CAST() macro helps ensure that the passed object is
 * really of type Serial.
 *
 * The KFile interface does not supply an open function: this is deliberate,
 * because in embedded systems each device has its own init parameters.
 * For the same reason, specific device settings like, for example,
 * the baudrate, are not part of interface and should be handled by the
 * driver-specific API.
 *
 * \version $Id$
 * \author Bernie Innocenti <bernie@codewiz.org>
 * \author Francesco Sacchi <batt@develer.com>
 * \author Daniele Basile <asterix@develer.com>
 */

#ifndef KERN_KFILE_H
#define KERN_KFILE_H

#include <cfg/compiler.h>
#include <cfg/debug.h>
#include <cfg/macros.h>

/* fwd decl */
struct KFile;

typedef int32_t kfile_off_t;     ///< KFile offset type, used by kfile_seek().

/**
 * Costants for repositioning read/write file offset.
 * These are needed because on some embedded platforms
 * ANSI I/O library may not be present.
 */
typedef enum KSeekMode
{
        KSM_SEEK_SET, ///< Seek from file beginning.
        KSM_SEEK_CUR, ///< Seek from file current position.
        KSM_SEEK_END, ///< Seek from file end.
} KSeekMode;

/**
 * Prototypes for KFile access functions.
 * I/O file functions must be ANSI compliant.
 * \note A KFile user can choose which function subset to implement,
 *       but has to set to NULL unimplemented features.
 * \{
 */

/**
 * Read from file.
 * \return the number of bytes read.
 */
typedef size_t (*ReadFunc_t) (struct KFile *fd, void *buf, size_t size);

/**
 * Write to file.
 * \return the number of bytes written.
 */
typedef size_t (*WriteFunc_t) (struct KFile *fd, const void *buf, size_t size);

/**
 * Seek into file (if seekable).
 * \return the new file offset or EOF on errors.
 */
typedef kfile_off_t (*SeekFunc_t) (struct KFile *fd, kfile_off_t offset, KSeekMode whence);

/**
 * Close and reopen file \a fd.
 * The reopening is done with the former file parameters and access modes.
 */
typedef struct KFile * (*ReOpenFunc_t) (struct KFile *fd);

/**
 * Close file.
 * \return 0 on success, EOF on errors.
 */
typedef int (*CloseFunc_t) (struct KFile *fd);

/**
 * Flush file I/O.
 * \return 0 on success, EOF on errors.
 */
typedef int (*FlushFunc_t) (struct KFile *fd);

/**
 * Get file error mask.
 * \return 0 on success or file error code, device specific.
 */
typedef int (*ErrorFunc_t) (struct KFile *fd);

/**
 * Clear errors.
 */
typedef void (*ClearErrFunc_t) (struct KFile *fd);
/* \} */

/**
 * Context data for callback functions which operate on
 * pseudo files.
 *
 * \note Remember to add the corresponding accessor functions
 *       when extending this interface.
 */
typedef struct KFile
{
        ReadFunc_t     read;
        WriteFunc_t    write;
        ReOpenFunc_t   reopen;
        CloseFunc_t    close;
        SeekFunc_t     seek;
        FlushFunc_t    flush;
        ErrorFunc_t    error;
        ClearErrFunc_t clearerr;
        DB(id_t _type); ///< Used to keep track, at runtime, of the class type.

        /* NOTE: these must _NOT_ be size_t on 16bit CPUs! */
        kfile_off_t    seek_pos;
        kfile_off_t    size;
} KFile;

/**
 * Generic implementation of kfile_seek.
 */
kfile_off_t kfile_genericSeek(struct KFile *fd, kfile_off_t offset, KSeekMode whence);

/**
 * Generic implementation of kfile_reopen.
 */
struct KFile * kfile_genericReopen(struct KFile *fd);

int kfile_genericClose(struct KFile *fd);

int kfile_putc(int c, struct KFile *fd); ///< Generic putc implementation using kfile_write.
int kfile_getc(struct KFile *fd);  ///< Generic getc implementation using kfile_read.
int kfile_printf(struct KFile *fd, const char *format, ...);
int kfile_print(struct KFile *fd, const char *s);
int kfile_gets(struct KFile *fd, char *buf, int size);
int kfile_gets_echo(struct KFile *fd, char *buf, int size, bool echo);

/**
 * Interface functions for KFile access.
 * \note Remember to change following functions if KFile interface changes.
 * \{
 */
INLINE size_t kfile_read(struct KFile *fd, void *buf, size_t size)
{
        ASSERT(fd->read);
        return fd->read(fd, buf, size);
}

INLINE size_t kfile_write(struct KFile *fd, const void *buf, size_t size)
{
        ASSERT(fd->write);
        return fd->write(fd, buf, size);
}

INLINE KFile * kfile_reopen(struct KFile *fd)
{
        ASSERT(fd->reopen);
        return fd->reopen(fd);
}

INLINE int kfile_close(struct KFile *fd)
{
        ASSERT(fd->close);
        return fd->close(fd);
}

INLINE kfile_off_t kfile_seek(struct KFile *fd, kfile_off_t offset, KSeekMode whence)
{
        ASSERT(fd->seek);
        return fd->seek(fd, offset, whence);
}

INLINE int kfile_flush(struct KFile *fd)
{
        ASSERT(fd->flush);
        return fd->flush(fd);
}

INLINE int kfile_error(struct KFile *fd)
{
        ASSERT(fd->error);
        return fd->error(fd);
}

INLINE void kfile_clearerr(struct KFile *fd)
{
        ASSERT(fd->clearerr);
        fd->clearerr(fd);
}
/* \} */

/**
 * Kfile test function.
 */
int kfile_testSetUp(void);
int kfile_testRun(KFile *fd, uint8_t *test_buf, uint8_t *save_buf, size_t size);
int kfile_testTearDown(void);

#endif /* KERN_KFILE_H */