/* data.h - Internal data object abstraction interface.

   Copyright (C) 2002, 2004, 2005 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.  */

#ifndef DATA_H

#define DATA_H

#if HAVE_CONFIG_H

#include <config.h>

#endif

#ifdef HAVE_SYS_TYPES_H

# include <sys/types.h>

#endif

#include <limits.h>

#include <stdint.h>

#include "gpgme.h"

/* Read up to SIZE bytes into buffer BUFFER from the data object with

   the handle DH.  Return the number of characters read, 0 on EOF and

   -1 on error.  If an error occurs, errno is set.  */

typedef gpgme_ssize_t (*gpgme_data_read_cb) (gpgme_data_t dh,

                                             void *buffer,

                                             size_t size);

/* Write up to SIZE bytes from buffer BUFFER to the data object with

   the handle DH.  Return the number of characters written, or -1 on

   error.  If an error occurs, errno is set.  */

typedef gpgme_ssize_t (*gpgme_data_write_cb) (gpgme_data_t dh,

                                              const void *buffer,

                                              size_t size);

/* Set the current position from where the next read or write starts

   in the data object with the handle DH to OFFSET, relative to

   WHENCE.  */

typedef gpgme_off_t (*gpgme_data_seek_cb) (gpgme_data_t dh,

                                            gpgme_off_t offset,

                                            int whence);

/* Release the data object with the handle DH.  */

typedef void (*gpgme_data_release_cb) (gpgme_data_t dh);

/* Get the FD associated with the handle DH, or -1.  */

typedef int (*gpgme_data_get_fd_cb) (gpgme_data_t dh);

struct _gpgme_data_cbs

{

  gpgme_data_read_cb read;

  gpgme_data_write_cb write;

  gpgme_data_seek_cb seek;

  gpgme_data_release_cb release;

  gpgme_data_get_fd_cb get_fd;

};

struct gpgme_data

{

  struct _gpgme_data_cbs *cbs;

  gpgme_data_encoding_t encoding;

  unsigned int propidx;  /* Index into the property table.  */

#ifdef PIPE_BUF

#define BUFFER_SIZE PIPE_BUF

#else

#ifdef _POSIX_PIPE_BUF

#define BUFFER_SIZE _POSIX_PIPE_BUF

#else

#define BUFFER_SIZE 512

#endif

#endif

  char pending[BUFFER_SIZE];

  int pending_len;

  /* File name of the data object.  */

  char *file_name;

  /* Hint on the to be expected total size of the data.  */

  gpgme_off_t size_hint;

  union

  {

    /* For gpgme_data_new_from_fd.  */

    int fd;

    /* For gpgme_data_new_from_stream.  */

    FILE *stream;

    /* For gpgme_data_new_from_estream.  */

    gpgrt_stream_t e_stream;

    /* For gpgme_data_new_from_cbs.  */

    struct

    {

      gpgme_data_cbs_t cbs;

      void *handle;

    } user;

    /* For gpgme_data_new_from_mem.  */

    struct

    {

      char *buffer;

      const char *orig_buffer;

      /* Allocated size of BUFFER.  */

      size_t size;

      size_t length;

      gpgme_off_t offset;

    } mem;

    /* For gpgme_data_new_from_read_cb.  */

    struct

    {

      int (*cb) (void *, char *, size_t, size_t *);

      void *handle;

    } old_user;

  } data;

};

/* The data property types.  */

typedef enum

  {

    DATA_PROP_NONE = 0,   /* Dummy property. */

    DATA_PROP_BLANKOUT    /* Do not return the held data.  */

  } data_prop_t;

/* Return the data object's serial number for handle DH.  */

uint64_t _gpgme_data_get_dserial (gpgme_data_t dh);

/* Set an internal property of a data object.  */

gpg_error_t _gpgme_data_set_prop (gpgme_data_t dh, uint64_t dserial,

                                  data_prop_t name, int value);

/* Get an internal property of a data object.  */

gpg_error_t _gpgme_data_get_prop (gpgme_data_t dh, uint64_t dserial,

                                  data_prop_t name, int *r_value);

/* Create a new data object.  */

gpgme_error_t _gpgme_data_new (gpgme_data_t *r_dh,

			       struct _gpgme_data_cbs *cbs);

void _gpgme_data_release (gpgme_data_t dh);

/* Get the file descriptor associated with DH, if possible.  Otherwise

   return -1.  */

int _gpgme_data_get_fd (gpgme_data_t dh);

/* Get the size-hint value for DH or 0 if not available.  */

gpgme_off_t _gpgme_data_get_size_hint (gpgme_data_t dh);

#endif	/* DATA_H */