1 /* Access functions for JISX0212 conversion.
2    Copyright (C) 1997-2022 Free Software Foundation, Inc.
3    This file is part of the GNU C Library.
4 
5    The GNU C Library is free software; you can redistribute it and/or
6    modify it under the terms of the GNU Lesser General Public
7    License as published by the Free Software Foundation; either
8    version 2.1 of the License, or (at your option) any later version.
9 
10    The GNU C Library 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
16    License along with the GNU C Library; if not, see
17    <https://www.gnu.org/licenses/>.  */
18 
19 #ifndef _JIS0212_H
20 #define _JIS0212_H	1
21 
22 #include <assert.h>
23 #include <gconv.h>
24 #include <stdint.h>
25 
26 
27 /* Struct for table with indices in mapping table.  */
28 struct jisx0212_idx
29 {
30   uint16_t start;
31   uint16_t end;
32   uint16_t idx;
33 };
34 
35 /* Conversion table.  */
36 extern const struct jisx0212_idx __jisx0212_to_ucs_idx[];
37 extern const uint16_t __jisx0212_to_ucs[];
38 
39 extern const struct jisx0212_idx __jisx0212_from_ucs_idx[];
40 extern const char __jisx0212_from_ucs[][2];
41 
42 
uint32_t(always_inline)43 static inline uint32_t
44 __attribute ((always_inline))
45 jisx0212_to_ucs4 (const unsigned char **s, size_t avail, unsigned char offset)
46 {
47   const struct jisx0212_idx *rp = __jisx0212_to_ucs_idx;
48   unsigned char ch = *(*s);
49   unsigned char ch2;
50   uint32_t wch = 0;
51   int idx;
52 
53   if (ch < offset || (ch - offset) < 0x22 || (ch - offset) > 0x6d)
54     return __UNKNOWN_10646_CHAR;
55 
56   if (avail < 2)
57     return 0;
58 
59   ch2 = (*s)[1];
60   if (ch2 < offset || (ch2 - offset) <= 0x20 || (ch2 - offset) >= 0x7f)
61     return __UNKNOWN_10646_CHAR;
62 
63   idx = (ch - offset - 0x21) * 94 + (ch2 - offset - 0x21);
64 
65   while (idx > rp->end)
66     ++rp;
67   if (idx >= rp->start)
68     wch = __jisx0212_to_ucs[rp->idx + idx - rp->start];
69 
70   if (wch != L'\0')
71     (*s) += 2;
72   else
73     wch = __UNKNOWN_10646_CHAR;
74 
75   return wch;
76 }
77 
78 
size_t(always_inline)79 static inline size_t
80 __attribute ((always_inline))
81 ucs4_to_jisx0212 (uint32_t wch, unsigned char *s, size_t avail)
82 {
83   const struct jisx0212_idx *rp = __jisx0212_from_ucs_idx;
84   unsigned int ch = (unsigned int) wch;
85   const char *cp;
86 
87   if (ch >= 0xffff)
88     return __UNKNOWN_10646_CHAR;
89   while (ch > rp->end)
90     ++rp;
91   if (ch >= rp->start)
92     cp = __jisx0212_from_ucs[rp->idx + ch - rp->start];
93   else
94     return __UNKNOWN_10646_CHAR;
95 
96   if (cp[0] == '\0')
97     return __UNKNOWN_10646_CHAR;
98 
99   s[0] = cp[0];
100   assert (cp[1] != '\0');
101   if (avail < 2)
102     return 0;
103 
104   s[1] = cp[1];
105   return 2;
106 }
107 
108 #endif /* jis0212.h */
109