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9c7ff11a | 1 | /* Internal header for proving correct grouping in strings of numbers. |
6d7e8eda | 2 | Copyright (C) 1995-2023 Free Software Foundation, Inc. |
9c7ff11a | 3 | This file is part of the GNU C Library. |
9c7ff11a UD |
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 | |
59ba27a6 | 16 | License along with the GNU C Library; if not, see |
5a82c748 | 17 | <https://www.gnu.org/licenses/>. */ |
9c7ff11a UD |
18 | |
19 | #include <limits.h> | |
20 | #include <stddef.h> | |
21 | #include <string.h> | |
22 | ||
23 | #ifndef MAX | |
24 | #define MAX(a,b) ({ typeof(a) _a = (a); typeof(b) _b = (b); \ | |
25 | _a > _b ? _a : _b; }) | |
26 | #endif | |
27 | ||
28 | #ifdef USE_WIDE_CHAR | |
29 | # include <wctype.h> | |
30 | # define L_(Ch) L##Ch | |
31 | # define UCHAR_TYPE wint_t | |
32 | # define STRING_TYPE wchar_t | |
33 | #else | |
34 | # define L_(Ch) Ch | |
35 | # define UCHAR_TYPE unsigned char | |
36 | # define STRING_TYPE char | |
37 | #endif | |
38 | ||
39 | #include "grouping.h" | |
40 | ||
41 | /* Find the maximum prefix of the string between BEGIN and END which | |
42 | satisfies the grouping rules. It is assumed that at least one digit | |
43 | follows BEGIN directly. */ | |
44 | ||
45 | const STRING_TYPE * | |
46 | #ifdef USE_WIDE_CHAR | |
47 | __correctly_grouped_prefixwc (const STRING_TYPE *begin, const STRING_TYPE *end, | |
48 | wchar_t thousands, | |
49 | #else | |
50 | __correctly_grouped_prefixmb (const STRING_TYPE *begin, const STRING_TYPE *end, | |
51 | const char *thousands, | |
52 | #endif | |
53 | const char *grouping) | |
54 | { | |
9c7ff11a UD |
55 | if (grouping == NULL) |
56 | return end; | |
57 | ||
17bfe595 SN |
58 | #ifdef USE_WIDE_CHAR |
59 | size_t thousands_len = 1; | |
60 | #else | |
61 | size_t thousands_len = strlen (thousands); | |
9c7ff11a UD |
62 | #endif |
63 | ||
17bfe595 | 64 | while (end - begin >= thousands_len) |
9c7ff11a | 65 | { |
17bfe595 | 66 | const STRING_TYPE *cp = end - thousands_len; |
9c7ff11a UD |
67 | const char *gp = grouping; |
68 | ||
69 | /* Check first group. */ | |
70 | while (cp >= begin) | |
71 | { | |
72 | #ifdef USE_WIDE_CHAR | |
73 | if (*cp == thousands) | |
74 | break; | |
75 | #else | |
69239bd7 AS |
76 | if (memcmp (cp, thousands, thousands_len) == 0) |
77 | break; | |
9c7ff11a UD |
78 | #endif |
79 | --cp; | |
80 | } | |
81 | ||
82 | /* We allow the representation to contain no grouping at all even if | |
83 | the locale specifies we can have grouping. */ | |
84 | if (cp < begin) | |
85 | return end; | |
86 | ||
69239bd7 | 87 | if (end - cp == (int) *gp + thousands_len) |
9c7ff11a UD |
88 | { |
89 | /* This group matches the specification. */ | |
90 | ||
91 | const STRING_TYPE *new_end; | |
92 | ||
93 | if (cp < begin) | |
94 | /* There is just one complete group. We are done. */ | |
95 | return end; | |
96 | ||
97 | /* CP points to a thousands separator character. The preceding | |
98 | remainder of the string from BEGIN to NEW_END is the part we | |
99 | will consider if there is a grouping error in this trailing | |
100 | portion from CP to END. */ | |
69239bd7 | 101 | new_end = cp; |
9c7ff11a UD |
102 | |
103 | /* Loop while the grouping is correct. */ | |
104 | while (1) | |
105 | { | |
106 | /* Get the next grouping rule. */ | |
107 | ++gp; | |
108 | if (*gp == 0) | |
109 | /* If end is reached use last rule. */ | |
110 | --gp; | |
111 | ||
112 | /* Skip the thousands separator. */ | |
113 | --cp; | |
114 | ||
115 | if (*gp == CHAR_MAX | |
116 | #if CHAR_MIN < 0 | |
117 | || *gp < 0 | |
118 | #endif | |
119 | ) | |
120 | { | |
121 | /* No more thousands separators are allowed to follow. */ | |
122 | while (cp >= begin) | |
123 | { | |
124 | #ifdef USE_WIDE_CHAR | |
125 | if (*cp == thousands) | |
126 | break; | |
127 | #else | |
69239bd7 | 128 | if (memcmp (cp, thousands, thousands_len) == 0) |
9c7ff11a UD |
129 | break; |
130 | #endif | |
131 | --cp; | |
132 | } | |
133 | ||
134 | if (cp < begin) | |
135 | /* OK, only digits followed. */ | |
136 | return end; | |
137 | } | |
138 | else | |
139 | { | |
140 | /* Check the next group. */ | |
141 | const STRING_TYPE *group_end = cp; | |
142 | ||
143 | while (cp >= begin) | |
144 | { | |
145 | #ifdef USE_WIDE_CHAR | |
146 | if (*cp == thousands) | |
147 | break; | |
148 | #else | |
69239bd7 | 149 | if (memcmp (cp, thousands, thousands_len) == 0) |
9c7ff11a UD |
150 | break; |
151 | #endif | |
152 | --cp; | |
153 | } | |
154 | ||
69239bd7 | 155 | if (cp < begin && group_end - cp <= (int) *gp + thousands_len - 1) |
9c7ff11a UD |
156 | /* Final group is correct. */ |
157 | return end; | |
158 | ||
69239bd7 | 159 | if (cp < begin || group_end - cp != (int) *gp + thousands_len - 1) |
9c7ff11a UD |
160 | /* Incorrect group. Punt. */ |
161 | break; | |
162 | } | |
163 | } | |
164 | ||
165 | /* The trailing portion of the string starting at NEW_END | |
166 | contains a grouping error. So we will look for a correctly | |
167 | grouped number in the preceding portion instead. */ | |
168 | end = new_end; | |
169 | } | |
170 | else | |
171 | { | |
172 | /* Even the first group was wrong; determine maximum shift. */ | |
69239bd7 AS |
173 | if (end - cp > (int) *gp + thousands_len) |
174 | end = cp + (int) *gp + thousands_len; | |
9c7ff11a UD |
175 | else if (cp < begin) |
176 | /* This number does not fill the first group, but is correct. */ | |
177 | return end; | |
178 | else | |
179 | /* CP points to a thousands separator character. */ | |
180 | end = cp; | |
181 | } | |
182 | } | |
183 | ||
184 | return MAX (begin, end); | |
185 | } |