/* Conversion module for UTF-16.

   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 byte order.  */

#define BOM_OE	0xfffe

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

#define FROM_LOOP		from_utf16_loop

#define TO_LOOP			to_utf16_loop

#define DEFINE_INIT		0

#define DEFINE_FINI		0

#define MIN_NEEDED_FROM		2

#define MAX_NEEDED_FROM		4

#define MIN_NEEDED_TO		4

#define ONE_DIRECTION		0

#define FROM_DIRECTION		(dir == from_utf16)

#define PREPARE_LOOP \

  enum direction dir = ((struct utf16_data *) step->__data)->dir;	      \

  enum variant var = ((struct utf16_data *) step->__data)->var;		      \

  if (__glibc_unlikely (data->__invocation_counter == 0))		      \

    {									      \

      if (var == UTF_16)						      \

	{								      \

	  if (FROM_DIRECTION)						      \

	    {								      \

	      /* 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 (!FROM_DIRECTION && !data->__internal_use)		      \

	    {								      \

	      /* Emit the Byte Order Mark.  */				      \

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

		return __GCONV_FULL_OUTPUT;				      \

									      \

	      put16u (outbuf, BOM);					      \

	      outbuf += 2;						      \

	    }								      \

	}								      \

      else if ((var == UTF_16LE && BYTE_ORDER == BIG_ENDIAN)		      \

	       || (var == UTF_16BE && BYTE_ORDER == LITTLE_ENDIAN))	      \

	data->__flags |= __GCONV_SWAP;					      \

    }									      \

  const int swap = data->__flags & __GCONV_SWAP;

#define EXTRA_LOOP_ARGS		, swap

/* Direction of the transformation.  */

enum direction

{

  illegal_dir,

  to_utf16,

  from_utf16

};

enum variant

{

  illegal_var,

  UTF_16,

  UTF_16LE,

  UTF_16BE

};

struct utf16_data

{

  enum direction dir;

  enum variant var;

};

extern int gconv_init (struct __gconv_step *step);

int

gconv_init (struct __gconv_step *step)

{

  /* Determine which direction.  */

  struct utf16_data *new_data;

  enum direction dir = illegal_dir;

  enum variant var = illegal_var;

  int result;

  if (__strcasecmp (step->__from_name, "UTF-16//") == 0)

    {

      dir = from_utf16;

      var = UTF_16;

    }

  else if (__strcasecmp (step->__to_name, "UTF-16//") == 0)

    {

      dir = to_utf16;

      var = UTF_16;

    }

  else if (__strcasecmp (step->__from_name, "UTF-16BE//") == 0)

    {

      dir = from_utf16;

      var = UTF_16BE;

    }

  else if (__strcasecmp (step->__to_name, "UTF-16BE//") == 0)

    {

      dir = to_utf16;

      var = UTF_16BE;

    }

  else if (__strcasecmp (step->__from_name, "UTF-16LE//") == 0)

    {

      dir = from_utf16;

      var = UTF_16LE;

    }

  else if (__strcasecmp (step->__to_name, "UTF-16LE//") == 0)

    {

      dir = to_utf16;

      var = UTF_16LE;

    }

  result = __GCONV_NOCONV;

  if (__builtin_expect (dir, to_utf16) != illegal_dir)

    {

      new_data = (struct utf16_data *) malloc (sizeof (struct utf16_data));

      result = __GCONV_NOMEM;

      if (new_data != NULL)

	{

	  new_data->dir = dir;

	  new_data->var = var;

	  step->__data = new_data;

	  if (dir == from_utf16)

	    {

	      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 = 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 = MAX_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 UTF-16.  */

#define MIN_NEEDED_INPUT	MIN_NEEDED_TO

#define MIN_NEEDED_OUTPUT	MIN_NEEDED_FROM

#define MAX_NEEDED_OUTPUT	MAX_NEEDED_FROM

#define LOOPFCT			TO_LOOP

#define BODY \

  {									      \

    uint32_t c = get32 (inptr);						      \

									      \

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

      {									      \

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

	   We must catch this.  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;							      \

      }									      \

									      \

    if (swap)								      \

      {									      \

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

	  {								      \

	    if (__glibc_unlikely (c >= 0x110000))			      \

	      {								      \

		STANDARD_TO_LOOP_ERR_HANDLER (4);			      \

	      }								      \

									      \

	    /* Generate a surrogate character.  */			      \

	    if (__glibc_unlikely (outptr + 4 > outend))			      \

	      {								      \

		/* Overflow in the output buffer.  */			      \

		result = __GCONV_FULL_OUTPUT;				      \

		break;							      \

	      }								      \

									      \

	    put16 (outptr, bswap_16 (0xd7c0 + (c >> 10)));		      \

	    outptr += 2;						      \

	    put16 (outptr, bswap_16 (0xdc00 + (c & 0x3ff)));		      \

	  }								      \

	else								      \

	  put16 (outptr, bswap_16 (c));					      \

      }									      \

    else								      \

      {									      \

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

	  {								      \

	    if (__glibc_unlikely (c >= 0x110000))			      \

	      {								      \

		STANDARD_TO_LOOP_ERR_HANDLER (4);			      \

	      }								      \

									      \

	    /* Generate a surrogate character.  */			      \

	    if (__glibc_unlikely (outptr + 4 > outend))			      \

	      {								      \

		/* Overflow in the output buffer.  */			      \

		result = __GCONV_FULL_OUTPUT;				      \

		break;							      \

	      }								      \

									      \

	    put16 (outptr, 0xd7c0 + (c >> 10));				      \

	    outptr += 2;						      \

	    put16 (outptr, 0xdc00 + (c & 0x3ff));			      \

	  }								      \

	else								      \

	  put16 (outptr, c);						      \

      }									      \

    outptr += 2;							      \

    inptr += 4;								      \

  }

#define LOOP_NEED_FLAGS

#define EXTRA_LOOP_DECLS \

	, int swap

#include <iconv/loop.c>

/* Convert from UTF-16 to the internal (UCS4-like) format.  */

#define MIN_NEEDED_INPUT	MIN_NEEDED_FROM

#define MAX_NEEDED_INPUT	MAX_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 (__builtin_expect (u1 < 0xd800, 1) || u1 > 0xdfff)		      \

	  {								      \

	    /* No surrogate.  */					      \

	    put32 (outptr, u1);						      \

	    inptr += 2;							      \

	  }								      \

	else								      \

	  {								      \

	    uint16_t u2;						      \

									      \

	    if (__glibc_unlikely (u1 >= 0xdc00))			      \

	      {								      \

		/* This is no valid first word for a surrogate.  */	      \

		STANDARD_FROM_LOOP_ERR_HANDLER (2);			      \

	      }								      \

									      \

	    /* It's a surrogate character.  At least the first word says      \

	       it is.  */						      \

	    if (__glibc_unlikely (inptr + 4 > inend))			      \

	      {								      \

		/* We don't have enough input for another complete input      \

		   character.  */					      \

		result = __GCONV_INCOMPLETE_INPUT;			      \

		break;							      \

	      }								      \

									      \

	    inptr += 2;							      \

	    u2 = bswap_16 (get16 (inptr));				      \

	    if (__builtin_expect (u2 < 0xdc00, 0)			      \

		|| __builtin_expect (u2 > 0xdfff, 0))			      \

	      {								      \

		/* This is no valid second word for a surrogate.  */	      \

		inptr -= 2;						      \

		STANDARD_FROM_LOOP_ERR_HANDLER (2);			      \

	      }								      \

									      \

	    put32 (outptr, ((u1 - 0xd7c0) << 10) + (u2 - 0xdc00));	      \

	    inptr += 2;							      \

	  }								      \

      }									      \

    else								      \

      {									      \

	if (__builtin_expect (u1 < 0xd800, 1) || u1 > 0xdfff)		      \

	  {								      \

	    /* No surrogate.  */					      \

	    put32 (outptr, u1);						      \

	    inptr += 2;							      \

	  }								      \

	else								      \

	  {								      \

	    if (__glibc_unlikely (u1 >= 0xdc00))			      \

	      {								      \

		/* This is no valid first word for a surrogate.  */	      \

		STANDARD_FROM_LOOP_ERR_HANDLER (2);			      \

	      }								      \

									      \

	    /* It's a surrogate character.  At least the first word says      \

	       it is.  */						      \

	    if (__glibc_unlikely (inptr + 4 > inend))			      \

	      {								      \

		/* We don't have enough input for another complete input      \

		   character.  */					      \

		result = __GCONV_INCOMPLETE_INPUT;			      \

		break;							      \

	      }								      \

									      \

	    inptr += 2;							      \

	    uint16_t u2 = get16 (inptr);				      \

	    if (__builtin_expect (u2 < 0xdc00, 0)			      \

		|| __builtin_expect (u2 > 0xdfff, 0))			      \

	      {								      \

		/* This is no valid second word for a surrogate.  */	      \

		inptr -= 2;						      \

		STANDARD_FROM_LOOP_ERR_HANDLER (2);			      \

	      }								      \

									      \

	    put32 (outptr, ((u1 - 0xd7c0) << 10) + (u2 - 0xdc00));	      \

	    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>