path: root/iconv/skeleton.c

/* Skeleton for a conversion module.
   Copyright (C) 1998, 1999, 2000 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998.

   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 file can be included to provide definitions of several things
   many modules have in common.  It can be customized using the following
   macros:

     DEFINE_INIT	define the default initializer.  This requires the
			following symbol to be defined.

     CHARSET_NAME	string with official name of the coded character
			set (in all-caps)

     DEFINE_FINI	define the default destructor function.

     MIN_NEEDED_FROM	minimal number of bytes needed for the from-charset.
     MIN_NEEDED_TO	likewise for the to-charset.

     MAX_NEEDED_FROM	maximal number of bytes needed for the from-charset.
			This macro is optional, it defaults to MIN_NEEDED_FROM.
     MAX_NEEDED_TO	likewise for the to-charset.

     DEFINE_DIRECTION_OBJECTS
			two objects will be defined to be used when the
			`gconv' function must only distinguish two
			directions.  This is implied by DEFINE_INIT.
			If this macro is not defined the following
			macro must be available.

     FROM_DIRECTION	this macro is supposed to return a value != 0
			if we convert from the current character set,
			otherwise it return 0.

     EMIT_SHIFT_TO_INIT	this symbol is optional.  If it is defined it
			defines some code which writes out a sequence
			of characters which bring the current state into
			the initial state.

     FROM_LOOP		name of the function implementing the conversion
			from the current characters.
     TO_LOOP		likewise for the other direction

     RESET_STATE	in case of an error we must reset the state for
			the rerun so this macro must be defined for
			stateful encodings.  It takes an argument which
			is nonzero when saving.

     RESET_INPUT_BUFFER	If the input character sets allow this the macro
			can be defined to reset the input buffer pointers
			to cover only those characters up to the error.

     FUNCTION_NAME	if not set the conversion function is named `gconv'.

     PREPARE_LOOP	optional code preparing the conversion loop.  Can
			contain variable definitions.
     END_LOOP		also optional, may be used to store information

     EXTRA_LOOP_ARGS	optional macro specifying extra arguments passed
			to loop function.
 */

#include <assert.h>
#include <gconv.h>
#include <string.h>
#define __need_size_t
#define __need_NULL
#include <stddef.h>

#ifndef STATIC_GCONV
# include <dlfcn.h>
#endif

#ifndef DL_CALL_FCT
# define DL_CALL_FCT(fct, args) fct args
#endif

/* The direction objects.  */
#if DEFINE_DIRECTION_OBJECTS || DEFINE_INIT
static int from_object;
static int to_object;

# ifndef FROM_DIRECTION
#  define FROM_DIRECTION (step->__data == &from_object)
# endif
#else
# ifndef FROM_DIRECTION
#  error "FROM_DIRECTION must be provided if direction objects are not used"
# endif
#endif


/* How many bytes are needed at most for the from-charset.  */
#ifndef MAX_NEEDED_FROM
# define MAX_NEEDED_FROM	MIN_NEEDED_FROM
#endif

/* Same for the to-charset.  */
#ifndef MAX_NEEDED_TO
# define MAX_NEEDED_TO		MIN_NEEDED_TO
#endif


/* Define macros which can access unaligned buffers.  These macros are
   supposed to be used only in code outside the inner loops.  For the inner
   loops we have other definitions which allow optimized access.  */
#ifdef _STRING_ARCH_unaligned
/* We can handle unaligned memory access.  */
# define get16u(addr) *((uint16_t *) (addr))
# define get32u(addr) *((uint32_t *) (addr))

/* We need no special support for writing values either.  */
# define put16u(addr, val) *((uint16_t *) (addr)) = (val)
# define put32u(addr, val) *((uint32_t *) (addr)) = (val)
#else
/* Distinguish between big endian and little endian.  */
# if __BYTE_ORDER == __LITTLE_ENDIAN
#  define get16u(addr) \
     (((__const unsigned char *) (addr))[1] << 8			      \
      | ((__const unsigned char *) (addr))[0])
#  define get32u(addr) \
     (((((__const unsigned char *) (addr))[3] << 8			      \
	| ((__const unsigned char *) (addr))[2]) << 8			      \
       | ((__const unsigned char *) (addr))[1]) << 8			      \
      | ((__const unsigned char *) (addr))[0])

#  define put16u(addr, val) \
     ({ uint16_t __val = (val);						      \
	((unsigned char *) (addr))[0] = __val;				      \
	((unsigned char *) (addr))[1] = __val >> 8;			      \
	(void) 0; })
#  define put32u(addr, val) \
     ({ uint32_t __val = (val);						      \
	((unsigned char *) (addr))[0] = __val;				      \
	__val >>= 8;							      \
	((unsigned char *) (addr))[1] = __val;				      \
	__val >>= 8;							      \
	((unsigned char *) (addr))[2] = __val;				      \
	__val >>= 8;							      \
	((unsigned char *) (addr))[3] = __val;				      \
	(void) 0; })
# else
#  define get16u(addr) \
     (((__const unsigned char *) (addr))[0] << 8			      \
      | ((__const unsigned char *) (addr))[1])
#  define get32u(addr) \
     (((((__const unsigned char *) (addr))[0] << 8			      \
	| ((__const unsigned char *) (addr))[1]) << 8			      \
       | ((__const unsigned char *) (addr))[2]) << 8			      \
      | ((__const unsigned char *) (addr))[3])

#  define put16u(addr, val) \
     ({ uint16_t __val = (val);						      \
	((unsigned char *) (addr))[1] = __val;				      \
	((unsigned char *) (addr))[0] = __val >> 8;			      \
	(void) 0; })
#  define put32u(addr, val) \
     ({ uint32_t __val = (val);						      \
	((unsigned char *) (addr))[3] = __val;				      \
	__val >>= 8;							      \
	((unsigned char *) (addr))[2] = __val;				      \
	__val >>= 8;							      \
	((unsigned char *) (addr))[1] = __val;				      \
	__val >>= 8;							      \
	((unsigned char *) (addr))[0] = __val;				      \
	(void) 0; })
# endif
#endif


/* For conversions from a fixed width character sets to another fixed width
   character set we we can define RESET_INPUT_BUFFER is necessary.  */
#if !defined RESET_INPUT_BUFFER && !defined SAVE_RESET_STATE
# if MIN_NEEDED_FROM == MAX_NEEDED_FROM && MIN_NEEDED_TO == MAX_NEEDED_TO
/* We have to use these `if's here since the compiler cannot know that
   (outbuf - outerr) is always divisible by MIN_NEEDED_TO.  */
#  define RESET_INPUT_BUFFER \
  if (MIN_NEEDED_FROM % MIN_NEEDED_TO == 0)				      \
    *inptrp -= (outbuf - outerr) * (MIN_NEEDED_FROM / MIN_NEEDED_TO);	      \
  else if (MIN_NEEDED_TO % MIN_NEEDED_FROM == 0)			      \
    *inptrp -= (outbuf - outerr) / (MIN_NEEDED_TO / MIN_NEEDED_FROM);	      \
  else									      \
    *inptrp -= ((outbuf - outerr) / MIN_NEEDED_TO) * MIN_NEEDED_FROM
# endif
#endif


/* The default init function.  It simply matches the name and initializes
   the step data to point to one of the objects above.  */
#if DEFINE_INIT
# ifndef CHARSET_NAME
#  error "CHARSET_NAME not defined"
# endif

int
gconv_init (struct __gconv_step *step)
{
  /* Determine which direction.  */
  if (strcmp (step->__from_name, CHARSET_NAME) == 0)
    {
      step->__data = &from_object;

      step->__min_needed_from = MIN_NEEDED_FROM;
      step->__max_needed_from = MAX_NEEDED_FROM;
      step->__min_needed_to = MIN_NEEDED_TO;
      step->__max_needed_to = MAX_NEEDED_TO;
    }
  else if (__builtin_expect (strcmp (step->__to_name, CHARSET_NAME), 0) == 0)
    {
      step->__data = &to_object;

      step->__min_needed_from = MIN_NEEDED_TO;
      step->__max_needed_from = MAX_NEEDED_TO;
      step->__min_needed_to = MIN_NEEDED_FROM;
      step->__max_needed_to = MAX_NEEDED_FROM;
    }
  else
    return __GCONV_NOCONV;

#ifdef RESET_STATE
  step->__stateful = 1;
#else