1/* Copyright (C) 1996-2021 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3 Written by Ulrich Drepper, <drepper@cygnus.com>.
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 _WEIGHTWC_H_
20#define _WEIGHTWC_H_ 1
21
22#include <libc-diag.h>
23
24/* Find index of weight. */
25static inline int32_t __attribute__ ((always_inline))
26findidx (const int32_t *table,
27 const int32_t *indirect,
28 const wint_t *extra,
29 const wint_t **cpp, size_t len)
30{
31 /* With GCC 7 when compiling with -Os the compiler warns that
32 seq1.back_us and seq2.back_us, which become *cpp, might be used
33 uninitialized. This is impossible as this function cannot be
34 called except in cases where those fields have been
35 initialized. */
36 DIAG_PUSH_NEEDS_COMMENT;
37 DIAG_IGNORE_Os_NEEDS_COMMENT (7, "-Wmaybe-uninitialized");
38 wint_t ch = *(*cpp)++;
39 DIAG_POP_NEEDS_COMMENT;
40 int32_t i = __collidx_table_lookup ((const char *) table, ch);
41
42 if (i >= 0)
43 /* This is an index into the weight table. Cool. */
44 return i;
45
46 /* Oh well, more than one sequence starting with this byte.
47 Search for the correct one. */
48 const int32_t *cp = (const int32_t *) &extra[-i];
49 --len;
50 while (1)
51 {
52 size_t nhere;
53 const int32_t *usrc = (const int32_t *) *cpp;
54
55 /* The first thing is the index. */
56 i = *cp++;
57
58 /* Next is the length of the byte sequence. These are always
59 short byte sequences so there is no reason to call any
60 function (even if they are inlined). */
61 nhere = *cp++;
62
63 if (i >= 0)
64 {
65 /* It is a single character. If it matches we found our
66 index. Note that at the end of each list there is an
67 entry of length zero which represents the single byte
68 sequence. The first (and here only) byte was tested
69 already. */
70 size_t cnt;
71
72 /* With GCC 5.3 when compiling with -Os the compiler warns
73 that seq2.back_us, which becomes usrc, might be used
74 uninitialized. This can't be true because we pass a length
75 of -1 for len at the same time which means that this loop
76 never executes. */
77 DIAG_PUSH_NEEDS_COMMENT;
78 DIAG_IGNORE_Os_NEEDS_COMMENT (5, "-Wmaybe-uninitialized");
79 for (cnt = 0; cnt < nhere && cnt < len; ++cnt)
80 if (cp[cnt] != usrc[cnt])
81 break;
82 DIAG_POP_NEEDS_COMMENT;
83
84 if (cnt == nhere)
85 {
86 /* Found it. */
87 *cpp += nhere;
88 return i;
89 }
90
91 /* Up to the next entry. */
92 cp += nhere;
93 }
94 else
95 {
96 /* This is a range of characters. First decide whether the
97 current byte sequence lies in the range. */
98 size_t cnt;
99 size_t offset;
100
101 /* With GCC 7 when compiling with -Os the compiler warns
102 that seq1.back_us and seq2.back_us, which become usrc,
103 might be used uninitialized. This is impossible for the
104 same reason as described above. */
105 DIAG_PUSH_NEEDS_COMMENT;
106 DIAG_IGNORE_Os_NEEDS_COMMENT (7, "-Wmaybe-uninitialized");
107 for (cnt = 0; cnt < nhere - 1 && cnt < len; ++cnt)
108 if (cp[cnt] != usrc[cnt])
109 break;
110 DIAG_POP_NEEDS_COMMENT;
111
112 if (cnt < nhere - 1 || cnt == len)
113 {
114 cp += 2 * nhere;
115 continue;
116 }
117
118 /* With GCC 7 when compiling with -Os the compiler warns
119 that seq1.back_us and seq2.back_us, which become usrc,
120 might be used uninitialized. This is impossible for the
121 same reason as described above. */
122 DIAG_PUSH_NEEDS_COMMENT;
123 DIAG_IGNORE_Os_NEEDS_COMMENT (7, "-Wmaybe-uninitialized");
124 if (cp[nhere - 1] > usrc[nhere - 1])
125 {
126 cp += 2 * nhere;
127 continue;
128 }
129 DIAG_POP_NEEDS_COMMENT;
130
131 if (cp[2 * nhere - 1] < usrc[nhere - 1])
132 {
133 cp += 2 * nhere;
134 continue;
135 }
136
137 /* This range matches the next characters. Now find
138 the offset in the indirect table. */
139 offset = usrc[nhere - 1] - cp[nhere - 1];
140 *cpp += nhere;
141
142 return indirect[-i + offset];
143 }
144 }
145
146 /* NOTREACHED */
147 return 0x43219876;
148}
149
150#endif /* weightwc.h */
151