1/* Look at first character in UTF-8 string, returning an error code.
2   Copyright (C) 1999-2002, 2006-2007, 2009-2010 Free Software Foundation, Inc.
3   Written by Bruno Haible <bruno@clisp.org>, 2001.
4
5   This program is free software: you can redistribute it and/or modify it
6   under the terms of the GNU Lesser General Public License as published
7   by the Free Software Foundation; either version 3 of the License, or
8   (at your option) any later version.
9
10   This program is distributed in the hope that it will be useful,
11   but WITHOUT ANY WARRANTY; without even the implied warranty of
12   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13   Lesser General Public License for more details.
14
15   You should have received a copy of the GNU Lesser General Public License
16   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
17
18#include <config.h>
19
20/* Specification.  */
21#include "unistr.h"
22
23int
24u8_mbtoucr (ucs4_t *puc, const uint8_t *s, size_t n)
25{
26  uint8_t c = *s;
27
28  if (c < 0x80)
29    {
30      *puc = c;
31      return 1;
32    }
33  else if (c >= 0xc2)
34    {
35      if (c < 0xe0)
36        {
37          if (n >= 2)
38            {
39              if ((s[1] ^ 0x80) < 0x40)
40                {
41                  *puc = ((unsigned int) (c & 0x1f) << 6)
42                         | (unsigned int) (s[1] ^ 0x80);
43                  return 2;
44                }
45              /* invalid multibyte character */
46            }
47          else
48            {
49              /* incomplete multibyte character */
50              *puc = 0xfffd;
51              return -2;
52            }
53        }
54      else if (c < 0xf0)
55        {
56          if (n >= 2)
57            {
58              if ((s[1] ^ 0x80) < 0x40
59                  && (c >= 0xe1 || s[1] >= 0xa0)
60                  && (c != 0xed || s[1] < 0xa0))
61                {
62                  if (n >= 3)
63                    {
64                      if ((s[2] ^ 0x80) < 0x40)
65                        {
66                          *puc = ((unsigned int) (c & 0x0f) << 12)
67                                 | ((unsigned int) (s[1] ^ 0x80) << 6)
68                                 | (unsigned int) (s[2] ^ 0x80);
69                          return 3;
70                        }
71                      /* invalid multibyte character */
72                    }
73                  else
74                    {
75                      /* incomplete multibyte character */
76                      *puc = 0xfffd;
77                      return -2;
78                    }
79                }
80              /* invalid multibyte character */
81            }
82          else
83            {
84              /* incomplete multibyte character */
85              *puc = 0xfffd;
86              return -2;
87            }
88        }
89      else if (c < 0xf8)
90        {
91          if (n >= 2)
92            {
93              if ((s[1] ^ 0x80) < 0x40
94                  && (c >= 0xf1 || s[1] >= 0x90)
95#if 1
96                  && (c < 0xf4 || (c == 0xf4 && s[1] < 0x90))
97#endif
98                 )
99                {
100                  if (n >= 3)
101                    {
102                      if ((s[2] ^ 0x80) < 0x40)
103                        {
104                          if (n >= 4)
105                            {
106                              if ((s[3] ^ 0x80) < 0x40)
107                                {
108                                  *puc = ((unsigned int) (c & 0x07) << 18)
109                                         | ((unsigned int) (s[1] ^ 0x80) << 12)
110                                         | ((unsigned int) (s[2] ^ 0x80) << 6)
111                                         | (unsigned int) (s[3] ^ 0x80);
112                                  return 4;
113                                }
114                              /* invalid multibyte character */
115                            }
116                          else
117                            {
118                              /* incomplete multibyte character */
119                              *puc = 0xfffd;
120                              return -2;
121                            }
122                        }
123                      /* invalid multibyte character */
124                    }
125                  else
126                    {
127                      /* incomplete multibyte character */
128                      *puc = 0xfffd;
129                      return -2;
130                    }
131                }
132              /* invalid multibyte character */
133            }
134          else
135            {
136              /* incomplete multibyte character */
137              *puc = 0xfffd;
138              return -2;
139            }
140        }
141#if 0
142      else if (c < 0xfc)
143        {
144          if (n >= 2)
145            {
146              if ((s[1] ^ 0x80) < 0x40
147                  && (c >= 0xf9 || s[1] >= 0x88))
148                {
149                  if (n >= 3)
150                    {
151                      if ((s[2] ^ 0x80) < 0x40)
152                        {
153                          if (n >= 4)
154                            {
155                              if ((s[3] ^ 0x80) < 0x40)
156                                {
157                                  if (n >= 5)
158                                    {
159                                      if ((s[4] ^ 0x80) < 0x40)
160                                        {
161                                          *puc = ((unsigned int) (c & 0x03) << 24)
162                                                 | ((unsigned int) (s[1] ^ 0x80) << 18)
163                                                 | ((unsigned int) (s[2] ^ 0x80) << 12)
164                                                 | ((unsigned int) (s[3] ^ 0x80) << 6)
165                                                 | (unsigned int) (s[4] ^ 0x80);
166                                          return 5;
167                                        }
168                                      /* invalid multibyte character */
169                                    }
170                                  else
171                                    {
172                                      /* incomplete multibyte character */
173                                      *puc = 0xfffd;
174                                      return -2;
175                                    }
176                                }
177                              /* invalid multibyte character */
178                            }
179                          else
180                            {
181                              /* incomplete multibyte character */
182                              *puc = 0xfffd;
183                              return -2;
184                            }
185                        }
186                      /* invalid multibyte character */
187                    }
188                  else
189                    {
190                      /* incomplete multibyte character */
191                      *puc = 0xfffd;
192                      return -2;
193                    }
194                }
195              /* invalid multibyte character */
196            }
197          else
198            {
199              /* incomplete multibyte character */
200              *puc = 0xfffd;
201              return -2;
202            }
203        }
204      else if (c < 0xfe)
205        {
206          if (n >= 2)
207            {
208              if ((s[1] ^ 0x80) < 0x40
209                  && (c >= 0xfd || s[1] >= 0x84))
210                {
211                  if (n >= 3)
212                    {
213                      if ((s[2] ^ 0x80) < 0x40)
214                        {
215                          if (n >= 4)
216                            {
217                              if ((s[3] ^ 0x80) < 0x40)
218                                {
219                                  if (n >= 5)
220                                    {
221                                      if ((s[4] ^ 0x80) < 0x40)
222                                        {
223                                          if (n >= 6)
224                                            {
225                                              if ((s[5] ^ 0x80) < 0x40)
226                                                {
227                                                  *puc = ((unsigned int) (c & 0x01) << 30)
228                                                         | ((unsigned int) (s[1] ^ 0x80) << 24)
229                                                         | ((unsigned int) (s[2] ^ 0x80) << 18)
230                                                         | ((unsigned int) (s[3] ^ 0x80) << 12)
231                                                         | ((unsigned int) (s[4] ^ 0x80) << 6)
232                                                         | (unsigned int) (s[5] ^ 0x80);
233                                                  return 6;
234                                                }
235                                              /* invalid multibyte character */
236                                            }
237                                          else
238                                            {
239                                              /* incomplete multibyte character */
240                                              *puc = 0xfffd;
241                                              return -2;
242                                            }
243                                        }
244                                      /* invalid multibyte character */
245                                    }
246                                  else
247                                    {
248                                      /* incomplete multibyte character */
249                                      *puc = 0xfffd;
250                                      return -2;
251                                    }
252                                }
253                              /* invalid multibyte character */
254                            }
255                          else
256                            {
257                              /* incomplete multibyte character */
258                              *puc = 0xfffd;
259                              return -2;
260                            }
261                        }
262                      /* invalid multibyte character */
263                    }
264                  else
265                    {
266                      /* incomplete multibyte character */
267                      *puc = 0xfffd;
268                      return -2;
269                    }
270                }
271              /* invalid multibyte character */
272            }
273          else
274            {
275              /* incomplete multibyte character */
276              *puc = 0xfffd;
277              return -2;
278            }
279        }
280#endif
281    }
282  /* invalid multibyte character */
283  *puc = 0xfffd;
284  return -1;
285}
286