1/* Tables for conversion to and from ISO-IR-165.
2 converting from UCS using gaps.
3 Copyright (C) 2000-2021 Free Software Foundation, Inc.
4 This file is part of the GNU C Library.
5 Contributed by Ulrich Drepper <drepper@cygnus.com>, 2000.
6
7 The GNU C Library is free software; you can redistribute it and/or
8 modify it under the terms of the GNU Lesser General Public
9 License as published by the Free Software Foundation; either
10 version 2.1 of the License, or (at your option) any later version.
11
12 The GNU C Library is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 Lesser General Public License for more details.
16
17 You should have received a copy of the GNU Lesser General Public
18 License along with the GNU C Library; if not, see
19 <https://www.gnu.org/licenses/>. */
20
21#ifndef _ISO_IR_165_H
22#define _ISO_IR_165_H 1
23
24#include <gconv.h>
25#include <stdint.h>
26
27struct gap
28{
29 uint16_t start;
30 uint16_t end;
31 int32_t idx;
32};
33
34/* Table for ISO-IR-165 (CCITT Chinese) to UCS4 conversion. */
35#define ISOIR165_FROMSIZE 0x2284
36extern const uint16_t __isoir165_to_tab[ISOIR165_FROMSIZE];
37
38
39/* XXX If we at some point need an offset value to decode the byte
40 sequences another parameter can be added. */
41static inline uint32_t
42__attribute ((always_inline))
43isoir165_to_ucs4 (const unsigned char **s, size_t avail)
44{
45 unsigned char ch = *(*s);
46 unsigned char ch2;
47 uint32_t res;
48
49 if (ch <= 0x20 || ch >= 0x7f)
50 return __UNKNOWN_10646_CHAR;
51
52 if (avail < 2)
53 return 0;
54
55 ch2 = (*s)[1];
56 if (ch2 <= 0x20 || ch2 >= 0x7f)
57 return __UNKNOWN_10646_CHAR;
58
59 res = __isoir165_to_tab[(ch - 0x21) * 94 + (ch2 - 0x21)];
60 if (res == 0)
61 return __UNKNOWN_10646_CHAR;
62
63 *s += 2;
64 return res;
65}
66
67
68/* Tables for ISO-IR-165 (CCITT Chinese) from UCS4 conversion. */
69extern const struct gap __isoir165_from_idx[];
70extern const char __isoir165_from_tab[];
71
72static inline size_t
73__attribute ((always_inline))
74ucs4_to_isoir165 (uint32_t wch, unsigned char *s, size_t avail)
75{
76 unsigned int ch = (unsigned int) wch;
77 const char *cp;
78 const struct gap *rp = __isoir165_from_idx;
79
80 if (ch > 0xffe5)
81 /* This is an illegal character. */
82 return __UNKNOWN_10646_CHAR;
83
84 while (ch > rp->end)
85 ++rp;
86 if (ch < rp->start)
87 /* This is an illegal character. */
88 return __UNKNOWN_10646_CHAR;
89
90 /* The two bytes following the index given in this record give the
91 encoding in ISO-IR-165. Unless the bytes are zero. */
92 cp = &__isoir165_from_tab[(ch + rp->idx) * 2];
93 if (*cp == '\0')
94 /* This is an illegal character. */
95 return __UNKNOWN_10646_CHAR;
96
97 if (avail < 2)
98 return 0;
99
100 s[0] = cp[0];
101 s[1] = cp[1];
102
103 return 2;
104}
105
106#endif /* iso-ir-165.h */
107