1/* Search character in UTF-8 string.
2   Copyright (C) 1999, 2002, 2006-2007, 2009-2010 Free Software Foundation,
3   Inc.
4   Written by Bruno Haible <bruno@clisp.org>, 2002.
5
6   This program is free software: you can redistribute it and/or modify it
7   under the terms of the GNU Lesser General Public License as published
8   by the Free Software Foundation; either version 3 of the License, or
9   (at your option) any later version.
10
11   This program is distributed in the hope that it will be useful,
12   but WITHOUT ANY WARRANTY; without even the implied warranty of
13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14   Lesser General Public License for more details.
15
16   You should have received a copy of the GNU Lesser General Public License
17   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
18
19#include <config.h>
20
21/* Specification.  */
22#include "unistr.h"
23
24uint8_t *
25u8_strrchr (const uint8_t *s, ucs4_t uc)
26{
27  /* Calling u8_strlen and then searching from the other end would cause more
28     memory accesses. Avoid that, at the cost of a few more comparisons.  */
29  uint8_t *result = NULL;
30  uint8_t c[6];
31
32  if (uc < 0x80)
33    {
34      uint8_t c0 = uc;
35
36      for (;; s++)
37        {
38          if (*s == c0)
39            result = (uint8_t *) s;
40          if (*s == 0)
41            break;
42        }
43    }
44  else
45    switch (u8_uctomb_aux (c, uc, 6))
46      {
47      case 2:
48        if (*s)
49          {
50            uint8_t c0 = c[0];
51            uint8_t c1 = c[1];
52
53            /* FIXME: Maybe walking the string via u8_mblen is a win?  */
54            for (;; s++)
55              {
56                if (s[1] == 0)
57                  break;
58                if (*s == c0 && s[1] == c1)
59                  result = (uint8_t *) s;
60              }
61          }
62        break;
63
64      case 3:
65        if (*s && s[1])
66          {
67            uint8_t c0 = c[0];
68            uint8_t c1 = c[1];
69            uint8_t c2 = c[2];
70
71            /* FIXME: Maybe walking the string via u8_mblen is a win?  */
72            for (;; s++)
73              {
74                if (s[2] == 0)
75                  break;
76                if (*s == c0 && s[1] == c1 && s[2] == c2)
77                  result = (uint8_t *) s;
78              }
79          }
80        break;
81
82      case 4:
83        if (*s && s[1] && s[2])
84          {
85            uint8_t c0 = c[0];
86            uint8_t c1 = c[1];
87            uint8_t c2 = c[2];
88            uint8_t c3 = c[3];
89
90            /* FIXME: Maybe walking the string via u8_mblen is a win?  */
91            for (;; s++)
92              {
93                if (s[3] == 0)
94                  break;
95                if (*s == c0 && s[1] == c1 && s[2] == c2 && s[3] == c3)
96                  result = (uint8_t *) s;
97              }
98          }
99        break;
100      }
101  return result;
102}
103