text: /*-------------------------------------------------------------------------
     mbrtoc32.c - convert UTF-8 to UTF-16
  
     Copyright (C) 2016, Philipp Klaus Krause, pkk@spth.de
  
     Modifications for PIC14 by
     Copyright (C) 2019 Gonzalo Pérez de Olaguer Córdoba <salo@gpoc.es>
  
     This library 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 2, or (at your option) any
     later version.
  
     This 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 General Public License for more details.
  
     You should have received a copy of the GNU General Public License 
     along with this library; see the file COPYING. If not, write to the
     Free Software Foundation, 51 Franklin Street, Fifth Floor, Boston,
     MA 02110-1301, USA.
  
     As a special exception, if you link this library with other files,
     some of which are compiled with SDCC, to produce an executable,
     this library does not by itself cause the resulting executable to
     be covered by the GNU General Public License. This exception does
     not however invalidate any other reasons why the executable file
     might be covered by the GNU General Public License.
  -------------------------------------------------------------------------*/
  
  #include <uchar.h>
  
  #include <limits.h>
  #include <wchar.h>
  
  size_t mbrtoc16(char16_t *restrict pc16, const char *restrict s, size_t n, mbstate_t *restrict ps)
  {
  	char32_t codepoint;
  	size_t ret;
  	static mbstate_t sps;
  	char16_t low_surrogate;
  
  	if(!s)
  #if defined(__SDCC_pic14)
  		/* try to minimize nested calls */
  		{ pc16 = 0; s = ""; n = 1; }
  #else
  		return(mbrtoc16(0, "", 1, ps));
  #endif
  
  	if(!ps)
  		ps = &sps;
  
  	if(!ps->c[0] && (ps->c[1] || ps->c[2]))
  	{
  		if(pc16)
  			*pc16 = ps->c[1] + (ps->c[2] << 8);
  		ps->c[1] = ps->c[2] = 0;
  		return(-3);
  	}
  
  	ret = mbrtowc(&codepoint, s, n, ps);
  
  	if(ret > MB_LEN_MAX)
  		return(ret);
  
  	if (codepoint <= 0xffff) // Basic multilingual plane
  	{
  		if(pc16)
  			*pc16 = codepoint;
  		return(ret);
  	}
  
  	codepoint -= 0x100000;
  	if(pc16)
  		*pc16 = ((codepoint >> 10) & 0x3ff) + 0xd800;
  	low_surrogate = (codepoint & 0x3ff) + 0xdc00;
  	ps->c[0] = 0;
  	ps->c[1] = low_surrogate & 0xff;
  	ps->c[2] = low_surrogate >> 8;
  
  	return(ret);
  }
  
  