/* Copyright (C) 1997-2024 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 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.

   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
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <https://www.gnu.org/licenses/>.  */

/* 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>
#include <bits/types/__mbstate_t.h>
#include <bits/types/wint_t.h>

#define __need_size_t
#define __need_wchar_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,
  __GCONV_SWAP = 0x0004,
  __GCONV_TRANSLIT = 0x0008
};


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


/* 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);

/* Type of a specialized conversion function for a single byte to INTERNAL.  */
typedef wint_t (*__gconv_btowc_fct) (struct __gconv_step *, unsigned char);

/* 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 *);


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

  /* For internal use by glibc.  (Accesses to this member must occur
     when the internal __gconv_lock mutex is acquired).  */
  int __counter;

  char *__from_name;
  char *__to_name;

  __gconv_fct __fct;
  __gconv_btowc_fct __btowc_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!  */
};


/* Combine conversion step description with data.  */
typedef struct __gconv_info
{
  size_t __nsteps;
  struct __gconv_step *__steps;
  __extension__ struct __gconv_step_data __data[0];
} *__gconv_t;

#endif /* gconv.h */
