1/* Copyright (C) 1995-2021 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3 Written by Ulrich Drepper <drepper@gnu.org>, 1995.
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
20#include <assert.h>
21#include <langinfo.h>
22#include <locale.h>
23#include <stddef.h>
24#include <stdint.h>
25#include <string.h>
26#include <sys/param.h>
27#include <libc-diag.h>
28
29#ifndef STRING_TYPE
30# define STRING_TYPE char
31# define USTRING_TYPE unsigned char
32# define STRCOLL __strcoll_l
33# define STRCMP strcmp
34# define WEIGHT_H "../locale/weight.h"
35# define SUFFIX MB
36# define L(arg) arg
37#endif
38
39#define CONCAT(a,b) CONCAT1(a,b)
40#define CONCAT1(a,b) a##b
41
42#include "../locale/localeinfo.h"
43#include WEIGHT_H
44
45/* Track status while looking for sequences in a string. */
46typedef struct
47{
48 int len; /* Length of the current sequence. */
49 size_t val; /* Position of the sequence relative to the
50 previous non-ignored sequence. */
51 size_t idxmax; /* Maximum index in sequences. */
52 size_t idxcnt; /* Current count of indices. */
53 size_t backw; /* Current Backward sequence index. */
54 size_t backw_stop; /* Index where the backward sequences stop. */
55 const USTRING_TYPE *us; /* The string. */
56 unsigned char rule; /* Saved rule for the first sequence. */
57 int32_t idx; /* Index to weight of the current sequence. */
58 int32_t save_idx; /* Save looked up index of a forward
59 sequence after the last backward
60 sequence. */
61 const USTRING_TYPE *back_us; /* Beginning of the backward sequence. */
62} coll_seq;
63
64/* Get next sequence. Traverse the string as required. */
65static __always_inline void
66get_next_seq (coll_seq *seq, int nrules, const unsigned char *rulesets,
67 const USTRING_TYPE *weights, const int32_t *table,
68 const USTRING_TYPE *extra, const int32_t *indirect,
69 int pass)
70{
71 size_t val = seq->val = 0;
72 int len = seq->len;
73 size_t backw_stop = seq->backw_stop;
74 size_t backw = seq->backw;
75 size_t idxcnt = seq->idxcnt;
76 size_t idxmax = seq->idxmax;
77 int32_t idx = seq->idx;
78 const USTRING_TYPE *us = seq->us;
79
80 while (len == 0)
81 {
82 ++val;
83 if (backw_stop != ~0ul)
84 {
85 /* There is something pushed. */
86 if (backw == backw_stop)
87 {
88 /* The last pushed character was handled. Continue
89 with forward characters. */
90 if (idxcnt < idxmax)
91 {
92 idx = seq->save_idx;
93 backw_stop = ~0ul;
94 }
95 else
96 {
97 /* Nothing anymore. The backward sequence ended with
98 the last sequence in the string. Note that len is
99 still zero. */
100 idx = 0;
101 break;
102 }
103 }
104 else
105 {
106 /* XXX Traverse BACKW sequences from the beginning of
107 BACKW_STOP to get the next sequence. Is ther a quicker way
108 to do this? */
109 size_t i = backw_stop;
110 us = seq->back_us;
111 while (i < backw)
112 {
113 int32_t tmp = findidx (table, indirect, extra, &us, -1);
114 idx = tmp & 0xffffff;
115 i++;
116 }
117 --backw;
118 us = seq->us;
119 }
120 }
121 else
122 {
123 backw_stop = idxmax;
124 int32_t prev_idx = idx;
125
126 while (*us != L('\0'))
127 {
128 int32_t tmp = findidx (table, indirect, extra, &us, -1);
129 unsigned char rule = tmp >> 24;
130 prev_idx = idx;
131 idx = tmp & 0xffffff;
132 idxcnt = idxmax++;
133
134 /* Save the rule for the first sequence. */
135 if (__glibc_unlikely (idxcnt == 0))
136 seq->rule = rule;
137
138 if ((rulesets[rule * nrules + pass]
139 & sort_backward) == 0)
140 /* No more backward characters to push. */
141 break;
142 ++idxcnt;
143 }
144
145 if (backw_stop >= idxcnt)
146 {
147 /* No sequence at all or just one. */
148 if (idxcnt == idxmax || backw_stop > idxcnt)
149 /* Note that len is still zero. */
150 break;
151
152 backw_stop = ~0ul;
153 }
154 else
155 {
156 /* We pushed backward sequences. If the stream ended with the
157 backward sequence, then we process the last sequence we
158 found. Otherwise we process the sequence before the last
159 one since the last one was a forward sequence. */
160 seq->back_us = seq->us;
161 seq->us = us;
162 backw = idxcnt;
163 if (idxmax > idxcnt)
164 {
165 backw--;
166 seq->save_idx = idx;
167 idx = prev_idx;
168 }
169 if (backw > backw_stop)
170 backw--;
171 }
172 }
173
174 /* With GCC 5.3 when compiling with -Os the compiler complains
175 that idx, taken from seq->idx (seq1 or seq2 from STRCOLL) may
176 be used uninitialized. In general this can't possibly be true
177 since seq1.idx and seq2.idx are initialized to zero in the
178 outer function. Only one case where seq->idx is restored from
179 seq->save_idx might result in an uninitialized idx value, but
180 it is guarded by a sequence of checks against backw_stop which
181 ensures that seq->save_idx was saved to first and contains a
182 valid value. */
183 DIAG_PUSH_NEEDS_COMMENT;
184 DIAG_IGNORE_Os_NEEDS_COMMENT (5, "-Wmaybe-uninitialized");
185 len = weights[idx++];
186 DIAG_POP_NEEDS_COMMENT;
187 /* Skip over indices of previous levels. */
188 for (int i = 0; i < pass; i++)
189 {
190 idx += len;
191 len = weights[idx];
192 idx++;
193 }
194 }
195
196 /* Update the structure. */
197 seq->val = val;
198 seq->len = len;
199 seq->backw_stop = backw_stop;
200 seq->backw = backw;
201 seq->idxcnt = idxcnt;
202 seq->idxmax = idxmax;
203 seq->us = us;
204 seq->idx = idx;
205}
206
207/* Compare two sequences. */
208static __always_inline int
209do_compare (coll_seq *seq1, coll_seq *seq2, int position,
210 const USTRING_TYPE *weights)
211{
212 int seq1len = seq1->len;
213 int seq2len = seq2->len;
214 size_t val1 = seq1->val;
215 size_t val2 = seq2->val;
216 int idx1 = seq1->idx;
217 int idx2 = seq2->idx;
218 int result = 0;
219
220 /* Test for position if necessary. */
221 if (position && val1 != val2)
222 {
223 result = val1 > val2 ? 1 : -1;
224 goto out;
225 }
226
227 /* Compare the two sequences. */
228 do
229 {
230 if (weights[idx1] != weights[idx2])
231 {
232 /* The sequences differ. */
233 result = weights[idx1] - weights[idx2];
234 goto out;
235 }
236
237 /* Increment the offsets. */
238 ++idx1;
239 ++idx2;
240
241 --seq1len;
242 --seq2len;
243 }
244 while (seq1len > 0 && seq2len > 0);
245
246 if (position && seq1len != seq2len)
247 result = seq1len - seq2len;
248
249out:
250 seq1->len = seq1len;
251 seq2->len = seq2len;
252 seq1->idx = idx1;
253 seq2->idx = idx2;
254 return result;
255}
256
257int
258STRCOLL (const STRING_TYPE *s1, const STRING_TYPE *s2, locale_t l)
259{
260 struct __locale_data *current = l->__locales[LC_COLLATE];
261 uint_fast32_t nrules = current->values[_NL_ITEM_INDEX (_NL_COLLATE_NRULES)].word;
262 /* We don't assign the following values right away since it might be
263 unnecessary in case there are no rules. */
264 const unsigned char *rulesets;
265 const int32_t *table;
266 const USTRING_TYPE *weights;
267 const USTRING_TYPE *extra;
268 const int32_t *indirect;
269
270 if (nrules == 0)
271 return STRCMP (s1, s2);
272
273 /* Catch empty strings. */
274 if (__glibc_unlikely (*s1 == '\0') || __glibc_unlikely (*s2 == '\0'))
275 return (*s1 != '\0') - (*s2 != '\0');
276
277 rulesets = (const unsigned char *)
278 current->values[_NL_ITEM_INDEX (_NL_COLLATE_RULESETS)].string;
279 table = (const int32_t *)
280 current->values[_NL_ITEM_INDEX (CONCAT(_NL_COLLATE_TABLE,SUFFIX))].string;
281 weights = (const USTRING_TYPE *)
282 current->values[_NL_ITEM_INDEX (CONCAT(_NL_COLLATE_WEIGHT,SUFFIX))].string;
283 extra = (const USTRING_TYPE *)
284 current->values[_NL_ITEM_INDEX (CONCAT(_NL_COLLATE_EXTRA,SUFFIX))].string;
285 indirect = (const int32_t *)
286 current->values[_NL_ITEM_INDEX (CONCAT(_NL_COLLATE_INDIRECT,SUFFIX))].string;
287
288 assert (((uintptr_t) table) % __alignof__ (table[0]) == 0);
289 assert (((uintptr_t) weights) % __alignof__ (weights[0]) == 0);
290 assert (((uintptr_t) extra) % __alignof__ (extra[0]) == 0);
291 assert (((uintptr_t) indirect) % __alignof__ (indirect[0]) == 0);
292
293 int result = 0, rule = 0;
294
295 /* With GCC 7 when compiling with -Os the compiler warns that
296 seq1.back_us and seq2.back_us might be used uninitialized.
297 Sometimes this warning appears at locations in locale/weightwc.h
298 where the actual use is, but on architectures other than x86_64,
299 x86 and s390x, a warning appears at the definitions of seq1 and
300 seq2. This uninitialized use is impossible for the same reason
301 as described in comments in locale/weightwc.h. */
302 DIAG_PUSH_NEEDS_COMMENT;
303 DIAG_IGNORE_Os_NEEDS_COMMENT (7, "-Wmaybe-uninitialized");
304 coll_seq seq1, seq2;
305 DIAG_POP_NEEDS_COMMENT;
306 seq1.len = 0;
307 seq1.idxmax = 0;
308 seq1.rule = 0;
309 seq2.len = 0;
310 seq2.idxmax = 0;
311
312 for (int pass = 0; pass < nrules; ++pass)
313 {
314 seq1.idxcnt = 0;
315 seq1.idx = 0;
316 seq2.idx = 0;
317 seq1.backw_stop = ~0ul;
318 seq1.backw = ~0ul;
319 seq2.idxcnt = 0;
320 seq2.backw_stop = ~0ul;
321 seq2.backw = ~0ul;
322
323 /* We need the elements of the strings as unsigned values since they
324 are used as indices. */
325 seq1.us = (const USTRING_TYPE *) s1;
326 seq2.us = (const USTRING_TYPE *) s2;
327
328 /* We assume that if a rule has defined `position' in one section
329 this is true for all of them. Please note that the localedef programs
330 makes sure that `position' is not used at the first level. */
331
332 int position = rulesets[rule * nrules + pass] & sort_position;
333
334 while (1)
335 {
336 get_next_seq (&seq1, nrules, rulesets, weights, table,
337 extra, indirect, pass);
338 get_next_seq (&seq2, nrules, rulesets, weights, table,
339 extra, indirect, pass);
340 /* See whether any or both strings are empty. */
341 if (seq1.len == 0 || seq2.len == 0)
342 {
343 if (seq1.len == seq2.len)
344 {
345 /* Both strings ended and are equal at this level. Do a
346 byte-level comparison to ensure that we don't waste time
347 going through multiple passes for totally equal strings
348 before proceeding to subsequent passes. */
349 if (pass == 0 && STRCMP (s1, s2) == 0)
350 return result;
351 else
352 break;
353 }
354
355 /* This means one string is shorter than the other. Find out
356 which one and return an appropriate value. */
357 return seq1.len == 0 ? -1 : 1;
358 }
359
360 result = do_compare (&seq1, &seq2, position, weights);
361 if (result != 0)
362 return result;
363 }
364
365 rule = seq1.rule;
366 }
367
368 return result;
369}
370libc_hidden_def (STRCOLL)
371
372#ifndef WIDE_CHAR_VERSION
373weak_alias (__strcoll_l, strcoll_l)
374#endif
375