sdcc/device/lib/pic14/libc/mbrtowc.c

   1 /*-------------------------------------------------------------------------
   2    mbrtowc.c - convert a multibyte sequence to a wide character
   3
   4    Copyright (C) 2016, Philipp Klaus Krause, pkk@spth.de
   5
   6    Modifications for PIC14 by
   7    Copyright (C) 2019 Gonzalo Pérez de Olaguer Córdoba <salo@gpoc.es>
   8
   9    This library is free software; you can redistribute it and/or modify it
  10    under the terms of the GNU General Public License as published by the
  11    Free Software Foundation; either version 2, or (at your option) any
  12    later version.
  13
  14    This library is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18
  19    You should have received a copy of the GNU General Public License
  20    along with this library; see the file COPYING. If not, write to the
  21    Free Software Foundation, 51 Franklin Street, Fifth Floor, Boston,
  22    MA 02110-1301, USA.
  23
  24    As a special exception, if you link this library with other files,
  25    some of which are compiled with SDCC, to produce an executable,
  26    this library does not by itself cause the resulting executable to
  27    be covered by the GNU General Public License. This exception does
  28    not however invalidate any other reasons why the executable file
  29    might be covered by the GNU General Public License.
  30 -------------------------------------------------------------------------*/
  31
  32 #include <wchar.h>
  33 #include <errno.h>
  34
  35 size_t mbrtowc(wchar_t *restrict pwc, const char *restrict s, size_t n, mbstate_t *restrict ps)
  36 {
  37         unsigned char first_byte;
  38         unsigned char seqlen;
  39         char mbseq[4];
  40         wchar_t codepoint;
  41         unsigned char i, j;
  42         static mbstate_t sps;
  43
  44         if(!s)
  45 #if defined(__SDCC_pic14)
  46                 /* try to minimize nested calls */
  47                 { pwc = 0; s = ""; n = 1; }
  48 #else
  49                 return(mbrtowc(0, "", 1, ps));
  50 #endif
  51         if(!n)
  52                 goto eilseq;
  53         if(!ps)
  54         {
  55                 ps = &sps;
  56         }
  57
  58         for(i = 0; ps->c[i] && i < 3; i++)
  59                 mbseq[i] = ps->c[i];
  60
  61         seqlen = 1;
  62         first_byte = ps->c[0] ? ps->c[0] : *s;
  63
  64         if(first_byte & 0x80)
  65         {
  66                 while (first_byte & (0x80 >> seqlen))
  67                         seqlen++;
  68                 first_byte &= (0xff >> (seqlen + 1));
  69         }
  70
  71         if(seqlen > 4)
  72                 goto eilseq;
  73
  74         if(i + n < seqlen) // Incomplete multibyte character
  75         {
  76                 for(;n-- ; i++)
  77                         ps->c[i] = *s++;
  78                 return(-2);
  79         }
  80
  81         for(j = 0; j < i; j++)
  82                 ps->c[j] = 0;
  83
  84         for(n = 1, i = i ? i : 1; i < seqlen; i++, n++)
  85         {
  86                 mbseq[i] = *s++;
  87                 if((mbseq[i] & 0xc0) != 0x80)
  88                         goto eilseq;
  89         }
  90
  91         codepoint = first_byte;
  92
  93         for(s = mbseq + 1, seqlen--; seqlen; seqlen--)
  94         {
  95                 codepoint <<= 6;
  96                 codepoint |= (*s & 0x3f);
  97                 s++;
  98         }
  99
 100         if(codepoint >= 0xd800 && codepoint <= 0xdfff) // UTF-16 surrogate.
 101                 return(-1);
 102
 103         if(pwc)
 104                 *pwc = codepoint;
 105         return(n);
 106
 107 eilseq:
 108         errno = EILSEQ;
 109         return(-1);
 110 }
 111