1/* Tables for conversion to and from ISO-IR-165.
2 converting from UCS using gaps.
3 Copyright (C) 2000-2023 Free Software Foundation, Inc.
4 This file is part of the GNU C Library.
5
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
10
11 The GNU C Library 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
17 License along with the GNU C Library; if not, see
18 <https://www.gnu.org/licenses/>. */
19
20#ifndef _ISO_IR_165_H
21#define _ISO_IR_165_H 1
22
23#include <gconv.h>
24#include <stdint.h>
25
26struct gap
27{
28 uint16_t start;
29 uint16_t end;
30 int32_t idx;
31};
32
33/* Table for ISO-IR-165 (CCITT Chinese) to UCS4 conversion. */
34#define ISOIR165_FROMSIZE 0x2284
35extern const uint16_t __isoir165_to_tab[ISOIR165_FROMSIZE];
36
37
38/* XXX If we at some point need an offset value to decode the byte
39 sequences another parameter can be added. */
40static inline uint32_t
41__attribute ((always_inline))
42isoir165_to_ucs4 (const unsigned char **s, size_t avail)
43{
44 unsigned char ch = *(*s);
45 unsigned char ch2;
46 uint32_t res;
47
48 if (ch <= 0x20 || ch >= 0x7f)
49 return __UNKNOWN_10646_CHAR;
50
51 if (avail < 2)
52 return 0;
53
54 ch2 = (*s)[1];
55 if (ch2 <= 0x20 || ch2 >= 0x7f)
56 return __UNKNOWN_10646_CHAR;
57
58 res = __isoir165_to_tab[(ch - 0x21) * 94 + (ch2 - 0x21)];
59 if (res == 0)
60 return __UNKNOWN_10646_CHAR;
61
62 *s += 2;
63 return res;
64}
65
66
67/* Tables for ISO-IR-165 (CCITT Chinese) from UCS4 conversion. */
68extern const struct gap __isoir165_from_idx[];
69extern const char __isoir165_from_tab[];
70
71static inline size_t
72__attribute ((always_inline))
73ucs4_to_isoir165 (uint32_t wch, unsigned char *s, size_t avail)
74{
75 unsigned int ch = (unsigned int) wch;
76 const char *cp;
77 const struct gap *rp = __isoir165_from_idx;
78
79 if (ch > 0xffe5)
80 /* This is an illegal character. */
81 return __UNKNOWN_10646_CHAR;
82
83 while (ch > rp->end)
84 ++rp;
85 if (ch < rp->start)
86 /* This is an illegal character. */
87 return __UNKNOWN_10646_CHAR;
88
89 /* The two bytes following the index given in this record give the
90 encoding in ISO-IR-165. Unless the bytes are zero. */
91 cp = &__isoir165_from_tab[(ch + rp->idx) * 2];
92 if (*cp == '\0')
93 /* This is an illegal character. */
94 return __UNKNOWN_10646_CHAR;
95
96 if (avail < 2)
97 return 0;
98
99 s[0] = cp[0];
100 s[1] = cp[1];
101
102 return 2;
103}
104
105#endif /* iso-ir-165.h */
106