/* Copyright (C) 1997, 1998, 1999, 2000 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public License as
   published by the Free Software Foundation; either version 2 of the
   License, or (at your option) any later version.

   The GNU C Library 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
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public
   License along with the GNU C Library; see the file COPYING.LIB.  If not,
   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.  */

/* This header provides no interface for a user to the internals of
   the gconv implementation in the libc.  Therefore there is no use
   for these definitions beside for writing additional gconv modules.  */

#ifndef _GCONV_H
#define _GCONV_H	1

#include <features.h>
#define __need_mbstate_t
#include <wchar.h>
#define __need_size_t
#include <stddef.h>

/* ISO 10646 value used to signal invalid value.  */
#define __UNKNOWN_10646_CHAR	((wchar_t) 0xfffd)

/* Error codes for gconv functions.  */
enum
{
  __GCONV_OK = 0,
  __GCONV_NOCONV,
  __GCONV_NODB,
  __GCONV_NOMEM,

  __GCONV_EMPTY_INPUT,
  __GCONV_FULL_OUTPUT,
  __GCONV_ILLEGAL_INPUT,
  __GCONV_INCOMPLETE_INPUT,

  __GCONV_ILLEGAL_DESCRIPTOR,
  __GCONV_INTERNAL_ERROR
};


/* Flags the `__gconv_open' function can set.  */
enum
{
  __GCONV_IS_LAST = 0x0001,
  __GCONV_IGNORE_ERRORS = 0x0002
};


/* Forward declarations.  */
struct __gconv_step;
struct __gconv_step_data;
struct __gconv_loaded_object;
struct __gconv_trans_data;


/* Type of a conversion function.  */
typedef int (*__gconv_fct) (struct __gconv_step *, struct __gconv_step_data *,
			    __const unsigned char **, __const unsigned char *,
			    unsigned char **, size_t *, int, int);

/* Constructor and destructor for local data for conversion step.  */
typedef int (*__gconv_init_fct) (struct __gconv_step *);
typedef void (*__gconv_end_fct) (struct __gconv_step *);


/* Type of a transliteration/transscription function.  */
typedef int (*__gconv_trans_fct) (struct __gconv_step *,
				  struct __gconv_step_data *, void *,
				  __const unsigned char *,
				  __const unsigned char **,
				  __const unsigned char *, unsigned char **,
				  size_t *);

/* Function to call to provide transliteration module with context.  */
typedef int (*__gconv_trans_context_fct) (void *, __const unsigned char *,
					  __const unsigned char *,
					  unsigned char *, unsigned char *);

/* Function to query module about supported encoded character sets.  */
typedef int (*__gconv_trans_query_fct) (__const char *, __const char ***,
					size_t *);

/* Constructor and destructor for local data for transliteration.  */
typedef int (*__gconv_trans_init_fct) (void **, const char *);
typedef void (*__gconv_trans_end_fct) (void *);

struct __gconv_trans_data
{
  /* Transliteration/Transscription function.  */
  __gconv_trans_fct __trans_fct;
  __gconv_trans_context_fct __trans_context_fct;
  __gconv_trans_end_fct __trans_end_fct;
  void *__data;
  struct __gconv_trans_data *__next;
};


/* Description of a conversion step.  */
struct __gconv_step
{
  struct __gconv_loaded_object *__shlib_handle;
  __const char *__modname;

  int __counter;

  char *__from_name;
  char *__to_name;

  __gconv_fct __fct;
  __gconv_init_fct __init_fct;
  __gconv_end_fct __end_fct;

  /* Information about the number of bytes needed or produced in this
     step.  This helps optimizing the buffer sizes.  */
  int __min_needed_from;
  int __max_needed_from;
  int __min_needed_to;
  int __max_needed_to;

  /* Flag whether this is a stateful encoding or not.  */
  int __stateful;

  void *__data;		/* Pointer to step-local data.  */
};

/* Additional data for steps in use of conversion descriptor.  This is
   allocated by the `init' function.  */
struct __gconv_step_data
{
  unsigned char *__outbuf;    /* Output buffer for this step.  */
  unsigned char *__outbufend; /* Address of first byte after the output
				 buffer.  */

  /* Is this the last module in the chain.  */
  int __flags;

  /* Counter for number of invocations of the module function for this
     descriptor.  */
  int __invocation_counter;

  /* Flag whether this is an internal use of the module (in the mb*towc*
     and wc*tomb* functions) or regular with iconv(3).  */
  int __internal_use;

  __mbstate_t *__statep;
  __mbstate_t __state;	/* This element must not be used directly by
			   any module; always use STATEP!  */

  /* Transliteration information.  */
  struct __gconv_trans_data *__trans;
};


/* Combine conversion step description with data.  */
typedef struct __gconv_info
{
  size_t __nsteps;
  struct __gconv_step *__steps;
  __extension__ struct __gconv_step_data __data __flexarr;
} *__gconv_t;

#endif /* gconv.h */
