/* Conversion module for Unicode

   Copyright (C) 1999-2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   Contributed by Ulrich Drepper <drepper@cygnus.com>, 1999.

   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

   <http://www.gnu.org/licenses/>.  */

#include <byteswap.h>

#include <dlfcn.h>

#include <gconv.h>

#include <stddef.h>

#include <stdint.h>

#include <stdlib.h>

#include <string.h>

/* This is the Byte Order Mark character (BOM).  */

#define BOM	0xfeff

/* And in the other endian format.  */

#define BOM_OE	0xfffe

/* Definitions used in the body of the `gconv' function.  */

#define FROM_LOOP		from_unicode_loop

#define TO_LOOP			to_unicode_loop

#define DEFINE_INIT		0

#define DEFINE_FINI		0

#define MIN_NEEDED_FROM		2

#define MIN_NEEDED_TO		4

#define ONE_DIRECTION		0

#define FROM_DIRECTION		(dir == from_unicode)

#define PREPARE_LOOP \

  enum direction dir = ((struct unicode_data *) step->__data)->dir;	      \

  int swap;								      \

  if (FROM_DIRECTION)							      \

    {									      \

      if (data->__invocation_counter == 0)				      \

	{								      \

	  /* We have to find out which byte order the file is encoded in.  */ \

	  if (inptr + 2 > inend)					      \

	    return (inptr == inend					      \

		    ? __GCONV_EMPTY_INPUT : __GCONV_INCOMPLETE_INPUT);	      \

									      \

	  if (get16u (inptr) == BOM)					      \

	    /* Simply ignore the BOM character.  */			      \

	    *inptrp = inptr += 2;					      \

	  else if (get16u (inptr) == BOM_OE)				      \

	    {								      \

	      data->__flags |= __GCONV_SWAP;				      \

	      *inptrp = inptr += 2;					      \

	    }								      \

	}								      \

    }									      \

  else if (!data->__internal_use && data->__invocation_counter == 0)	      \

    {									      \

      /* Emit the Byte Order Mark.  */					      \

      if (__glibc_unlikely (outbuf + 2 > outend))			      \

	return __GCONV_FULL_OUTPUT;					      \

									      \

      put16u (outbuf, BOM);						      \

      outbuf += 2;							      \

    }									      \

  swap = data->__flags & __GCONV_SWAP;

#define EXTRA_LOOP_ARGS		, swap

/* Direction of the transformation.  */

enum direction

{

  illegal_dir,

  to_unicode,

  from_unicode

};

struct unicode_data

{

  enum direction dir;

};

extern int gconv_init (struct __gconv_step *step);

int

gconv_init (struct __gconv_step *step)

{

  /* Determine which direction.  */

  struct unicode_data *new_data;

  enum direction dir = illegal_dir;

  int result;

  if (strcmp (step->__from_name, "UNICODE//") == 0)

    dir = from_unicode;

  else

    dir = to_unicode;

  new_data = (struct unicode_data *) malloc (sizeof (struct unicode_data));

  result = __GCONV_NOMEM;

  if (new_data != NULL)

    {

      new_data->dir = dir;

      step->__data = new_data;

      if (dir == from_unicode)

	{

	  step->__min_needed_from = MIN_NEEDED_FROM;

	  step->__max_needed_from = MIN_NEEDED_FROM;

	  step->__min_needed_to = MIN_NEEDED_TO;

	  step->__max_needed_to = MIN_NEEDED_TO;

	}

      else

	{

	  step->__min_needed_from = MIN_NEEDED_TO;

	  step->__max_needed_from = MIN_NEEDED_TO;

	  step->__min_needed_to = MIN_NEEDED_FROM;

	  step->__max_needed_to = MIN_NEEDED_FROM;

	}

      step->__stateful = 0;

      result = __GCONV_OK;

    }

  return result;

}

extern void gconv_end (struct __gconv_step *data);

void

gconv_end (struct __gconv_step *data)

{

  free (data->__data);

}

/* Convert from the internal (UCS4-like) format to UCS2.  */

#define MIN_NEEDED_INPUT	MIN_NEEDED_TO

#define MIN_NEEDED_OUTPUT	MIN_NEEDED_FROM

#define LOOPFCT			TO_LOOP

#define BODY \

  {									      \

    uint32_t c = get32 (inptr);						      \

									      \

    if (__glibc_unlikely (c >= 0x10000))				      \

      {									      \

	UNICODE_TAG_HANDLER (c, 4);					      \

	STANDARD_TO_LOOP_ERR_HANDLER (4);				      \

      }									      \

    else if (__glibc_unlikely (c >= 0xd800 && c < 0xe000))		      \

      {									      \

	/* Surrogate characters in UCS-4 input are not valid.		      \

	   We must catch this, because the UCS-2 output might be	      \

	   interpreted as UTF-16 by other programs.  If we let		      \

	   surrogates pass through, attackers could make a security	      \

	   hole exploit by synthesizing any desired plane 1-16		      \

	   character.  */						      \

	result = __GCONV_ILLEGAL_INPUT;					      \

	if (! ignore_errors_p ())					      \

	  break;							      \

	inptr += 4;							      \

	++*irreversible;						      \

	continue;							      \

      }									      \

    else								      \

      {									      \

	put16 (outptr, c);						      \

	outptr += 2;							      \

      }									      \

									      \

    inptr += 4;								      \

  }

#define LOOP_NEED_FLAGS

#define EXTRA_LOOP_DECLS \

	, int swap

#include <iconv/loop.c>

/* Convert from UCS2 to the internal (UCS4-like) format.  */

#define MIN_NEEDED_INPUT	MIN_NEEDED_FROM

#define MIN_NEEDED_OUTPUT	MIN_NEEDED_TO

#define LOOPFCT			FROM_LOOP

#define BODY \

  {									      \

    uint16_t u1 = get16 (inptr);					      \

									      \

    if (swap)								      \

      u1 = bswap_16 (u1);						      \

									      \

    if (__glibc_unlikely (u1 >= 0xd800 && u1 < 0xe000))			      \

      {									      \

	/* Surrogate characters in UCS-2 input are not valid.  Reject	      \

	   them.  (Catching this here is not security relevant.)  */	      \

	STANDARD_FROM_LOOP_ERR_HANDLER (2);				      \

      }									      \

									      \

    put32 (outptr, u1);							      \

									      \

    inptr += 2;								      \

    outptr += 4;							      \

  }

#define LOOP_NEED_FLAGS

#define EXTRA_LOOP_DECLS \

	, int swap

#include <iconv/loop.c>

/* Now define the toplevel functions.  */

#include <iconv/skeleton.c>