/* data-stream.c - A stream 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

#include <stdio.h>

#ifdef HAVE_SYS_TYPES_H

# include <sys/types.h>

#endif

#include "debug.h"

#include "data.h"

static gpgme_ssize_t

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

{

  size_t amt = fread (buffer, 1, size, dh->data.stream);

  if (amt > 0)

    return amt;

  return ferror (dh->data.stream) ? -1 : 0;

}

static gpgme_ssize_t

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

{

  size_t amt = fwrite (buffer, 1, size, dh->data.stream);

  if (amt > 0)

    return amt;

  return ferror (dh->data.stream) ? -1 : 0;

}

static gpgme_off_t

stream_seek (gpgme_data_t dh, gpgme_off_t offset, int whence)

{

  int err;

#ifdef HAVE_FSEEKO

  err = fseeko (dh->data.stream, offset, whence);

#else

  /* FIXME: Check for overflow, or at least bail at compilation.  */

  err = fseek (dh->data.stream, offset, whence);

#endif

  if (err)

    return -1;

#ifdef HAVE_FSEEKO

  return ftello (dh->data.stream);

#else

  return ftell (dh->data.stream);

#endif

}

static int

stream_get_fd (gpgme_data_t dh)

{

  fflush (dh->data.stream);

  return fileno (dh->data.stream);

}

static struct _gpgme_data_cbs stream_cbs =

  {

    stream_read,

    stream_write,

    stream_seek,

    NULL,

    stream_get_fd

  };

gpgme_error_t

gpgme_data_new_from_stream (gpgme_data_t *r_dh, FILE *stream)

{

  gpgme_error_t err;

  TRACE_BEG1 (DEBUG_DATA, "gpgme_data_new_from_stream", r_dh, "stream=%p",

	      stream);

  err = _gpgme_data_new (r_dh, &stream_cbs);

  if (err)

    return TRACE_ERR (err);

  (*r_dh)->data.stream = stream;

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

}