/* Conversion UTF-8 to UCS-4.
   Copyright (C) 2001-2002, 2006-2007 Free Software Foundation, Inc.
   Written by Bruno Haible <bruno@clisp.org>, 2001.

   This program is free software: you can redistribute it and/or modify it
   under the terms of the GNU General Public License as published
   by the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program 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 General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

#include <config.h>

/* Specification.  */
#include "unistr.h"

#if HAVE_INLINE

int
u8_mbtouc_aux (ucs4_t *puc, const uint8_t *s, size_t n)
{
  uint8_t c = *s;

  if (c >= 0xc2)
    {
      if (c < 0xe0)
	{
	  if (n >= 2)
	    {
	      if ((s[1] ^ 0x80) < 0x40)
		{
		  *puc = ((unsigned int) (c & 0x1f) << 6)
		         | (unsigned int) (s[1] ^ 0x80);
		  return 2;
		}
	      /* invalid multibyte character */
	    }
	  else
	    {
	      /* incomplete multibyte character */
	      *puc = 0xfffd;
	      return n;
	    }
	}
      else if (c < 0xf0)
	{
	  if (n >= 3)
	    {
	      if ((s[1] ^ 0x80) < 0x40 && (s[2] ^ 0x80) < 0x40
		  && (c >= 0xe1 || s[1] >= 0xa0)
		  && (c != 0xed || s[1] < 0xa0))
		{
		  *puc = ((unsigned int) (c & 0x0f) << 12)
		         | ((unsigned int) (s[1] ^ 0x80) << 6)
		         | (unsigned int) (s[2] ^ 0x80);
		  return 3;
		}
	      /* invalid multibyte character */
	    }
	  else
	    {
	      /* incomplete multibyte character */
	      *puc = 0xfffd;
	      return n;
	    }
	}
      else if (c < 0xf8)
	{
	  if (n >= 4)
	    {
	      if ((s[1] ^ 0x80) < 0x40 && (s[2] ^ 0x80) < 0x40
		  && (s[3] ^ 0x80) < 0x40
		  && (c >= 0xf1 || s[1] >= 0x90)
#if 1
		  && (c < 0xf4 || (c == 0xf4 && s[1] < 0x90))
#endif
		 )
		{
		  *puc = ((unsigned int) (c & 0x07) << 18)
		         | ((unsigned int) (s[1] ^ 0x80) << 12)
		         | ((unsigned int) (s[2] ^ 0x80) << 6)
		         | (unsigned int) (s[3] ^ 0x80);
		  return 4;
		}
	      /* invalid multibyte character */
	    }
	  else
	    {
	      /* incomplete multibyte character */
	      *puc = 0xfffd;
	      return n;
	    }
	}
#if 0
      else if (c < 0xfc)
	{
	  if (n >= 5)
	    {
	      if ((s[1] ^ 0x80) < 0x40 && (s[2] ^ 0x80) < 0x40
		  && (s[3] ^ 0x80) < 0x40 && (s[4] ^ 0x80) < 0x40
		  && (c >= 0xf9 || s[1] >= 0x88))
		{
		  *puc = ((unsigned int) (c & 0x03) << 24)
		         | ((unsigned int) (s[1] ^ 0x80) << 18)
		         | ((unsigned int) (s[2] ^ 0x80) << 12)
		         | ((unsigned int) (s[3] ^ 0x80) << 6)
		         | (unsigned int) (s[4] ^ 0x80);
		  return 5;
		}
	      /* invalid multibyte character */
	    }
	  else
	    {
	      /* incomplete multibyte character */
	      *puc = 0xfffd;
	      return n;
	    }
	}
      else if (c < 0xfe)
	{
	  if (n >= 6)
	    {
	      if ((s[1] ^ 0x80) < 0x40 && (s[2] ^ 0x80) < 0x40
		  && (s[3] ^ 0x80) < 0x40 && (s[4] ^ 0x80) < 0x40
		  && (s[5] ^ 0x80) < 0x40
		  && (c >= 0xfd || s[1] >= 0x84))
		{
		  *puc = ((unsigned int) (c & 0x01) << 30)
		         | ((unsigned int) (s[1] ^ 0x80) << 24)
		         | ((unsigned int) (s[2] ^ 0x80) << 18)
		         | ((unsigned int) (s[3] ^ 0x80) << 12)
		         | ((unsigned int) (s[4] ^ 0x80) << 6)
		         | (unsigned int) (s[5] ^ 0x80);
		  return 6;
		}
	      /* invalid multibyte character */
	    }
	  else
	    {
	      /* incomplete multibyte character */
	      *puc = 0xfffd;
	      return n;
	    }
	}
#endif
    }
  /* invalid multibyte character */
  *puc = 0xfffd;
  return 1;
}

#endif
