/* data-user.c - A user callback based data object.

   Copyright (C) 2002, 2004 g10 Code GmbH

   This file is part of GPGME.

   GPGME is free software; you can redistribute it and/or modify it

   under the terms of the GNU Lesser General Public License as

   published by the Free Software Foundation; either version 2.1 of

   the License, or (at your option) any later version.

   GPGME 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

   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public

   License along with this program; if not, write to the Free Software

   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA

   02111-1307, USA.  */

#if HAVE_CONFIG_H

#include <config.h>

#endif

#ifdef HAVE_SYS_TYPES_H

# include <sys/types.h>

#endif

#include <errno.h>

#include "debug.h"

#include "data.h"

static gpgme_ssize_t

user_read (gpgme_data_t dh, void *buffer, size_t size)

{

  if (!dh->data.user.cbs->read)

    {

      gpg_err_set_errno (EBADF);

      return -1;

    }

  return (*dh->data.user.cbs->read) (dh->data.user.handle, buffer, size);

}

static gpgme_ssize_t

user_write (gpgme_data_t dh, const void *buffer, size_t size)

{

  if (!dh->data.user.cbs->write)

    {

      gpg_err_set_errno (EBADF);

      return -1;

    }

  return (*dh->data.user.cbs->write) (dh->data.user.handle, buffer, size);

}

static gpgme_off_t

user_seek (gpgme_data_t dh, gpgme_off_t offset, int whence)

{

  if (!dh->data.user.cbs->seek)

    {

      gpg_err_set_errno (EBADF);

      return -1;

    }

  return (*dh->data.user.cbs->seek) (dh->data.user.handle, offset, whence);

}

static void

user_release (gpgme_data_t dh)

{

  if (dh->data.user.cbs->release)

    (*dh->data.user.cbs->release) (dh->data.user.handle);

}

static struct _gpgme_data_cbs user_cbs =

  {

    user_read,

    user_write,

    user_seek,

    user_release,

    NULL

  };

gpgme_error_t

gpgme_data_new_from_cbs (gpgme_data_t *r_dh, gpgme_data_cbs_t cbs, void *handle)

{

  gpgme_error_t err;

  TRACE_BEG1 (DEBUG_DATA, "gpgme_data_new_from_cbs", r_dh, "handle=%p", handle);

  err = _gpgme_data_new (r_dh, &user_cbs);

  if (err)

    return TRACE_ERR (err);

  (*r_dh)->data.user.cbs = cbs;

  (*r_dh)->data.user.handle = handle;

  return TRACE_SUC1 ("dh=%p", *r_dh);

}