Remove printf extension
[wimlib] / src / encoding.c
1 /*
2  * encoding.c
3  */
4
5 /*
6  * Copyright (C) 2012, 2013 Eric Biggers
7  *
8  * This file is part of wimlib, a library for working with WIM files.
9  *
10  * wimlib is free software; you can redistribute it and/or modify it under the
11  * terms of the GNU General Public License as published by the Free
12  * Software Foundation; either version 3 of the License, or (at your option)
13  * any later version.
14  *
15  * wimlib is distributed in the hope that it will be useful, but WITHOUT ANY
16  * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
17  * A PARTICULAR PURPOSE. See the GNU General Public License for more
18  * details.
19  *
20  * You should have received a copy of the GNU General Public License
21  * along with wimlib; if not, see http://www.gnu.org/licenses/.
22  */
23
24 #ifdef HAVE_CONFIG_H
25 #  include "config.h"
26 #endif
27
28 #include "wimlib.h"
29 #include "wimlib/assert.h"
30 #include "wimlib/encoding.h"
31 #include "wimlib/endianness.h"
32 #include "wimlib/error.h"
33 #include "wimlib/list.h"
34 #include "wimlib/util.h"
35
36 #include <errno.h>
37 #include <iconv.h>
38 #include <pthread.h>
39 #include <stdlib.h>
40 #include <string.h>
41
42 #ifdef HAVE_ALLOCA_H
43 #  include <alloca.h>
44 #endif
45
46 bool wimlib_mbs_is_utf8 = !TCHAR_IS_UTF16LE;
47
48 /* List of iconv_t conversion descriptors for a specific character conversion.
49  * The idea is that it is not thread-safe to have just one conversion
50  * descriptor, but it also is inefficient to open a new conversion descriptor to
51  * convert every string.  Both these problems can be solved by maintaining a
52  * list of conversion descriptors; then, a thread can use an existing conversion
53  * descriptor if available. */
54 struct iconv_list_head {
55         const char *from_encoding;
56         const char *to_encoding;
57         struct list_head list;
58         pthread_mutex_t mutex;
59 };
60
61 struct iconv_node {
62         iconv_t cd;
63         struct list_head list;
64         struct iconv_list_head *head;
65 };
66
67 #define ICONV_LIST(name, from, to)                      \
68 struct iconv_list_head name = {                         \
69         .from_encoding = from,                          \
70         .to_encoding = to,                              \
71         .list = LIST_HEAD_INIT(name.list),              \
72         .mutex = PTHREAD_MUTEX_INITIALIZER,             \
73 }
74
75 static iconv_t *
76 get_iconv(struct iconv_list_head *head)
77 {
78         iconv_t cd;
79         iconv_t *cd_p;
80         struct iconv_node *i;
81
82         pthread_mutex_lock(&head->mutex);
83         if (list_empty(&head->list)) {
84                 cd = iconv_open(head->to_encoding, head->from_encoding);
85                 if (cd == (iconv_t)-1) {
86                         ERROR_WITH_ERRNO("Failed to open iconv from %s to %s",
87                                          head->from_encoding, head->to_encoding);
88                         cd_p = NULL;
89                 } else {
90                         i = MALLOC(sizeof(struct iconv_node));
91                         if (i) {
92                                 i->head = head;
93                                 i->cd = cd;
94                                 cd_p = &i->cd;
95                         } else {
96                                 iconv_close(cd);
97                                 cd_p = NULL;
98                         }
99                 }
100         } else {
101                 i = container_of(head->list.next, struct iconv_node, list);
102                 list_del(head->list.next);
103                 cd_p = &i->cd;
104         }
105         pthread_mutex_unlock(&head->mutex);
106         return cd_p;
107 }
108
109 static void
110 put_iconv(iconv_t *cd)
111 {
112         int errno_save = errno;
113         struct iconv_node *i = container_of(cd, struct iconv_node, cd);
114         struct iconv_list_head *head = i->head;
115
116         pthread_mutex_lock(&head->mutex);
117         list_add(&i->list, &head->list);
118         pthread_mutex_unlock(&head->mutex);
119         errno = errno_save;
120 }
121
122 #define DEFINE_CHAR_CONVERSION_FUNCTIONS(varname1, longname1, chartype1,\
123                                          varname2, longname2, chartype2,\
124                                          earlyreturn_on_utf8_locale,    \
125                                          earlyreturn_expr,              \
126                                          worst_case_len_expr,           \
127                                          err_return,                    \
128                                          err_msg,                       \
129                                          modifier)                      \
130 static ICONV_LIST(iconv_##varname1##_to_##varname2,                     \
131                   longname1, longname2);                                \
132                                                                         \
133 modifier int                                                            \
134 varname1##_to_##varname2##_nbytes(const chartype1 *in, size_t in_nbytes,\
135                                   size_t *out_nbytes_ret)               \
136 {                                                                       \
137         iconv_t *cd = get_iconv(&iconv_##varname1##_to_##varname2);     \
138         if (cd == NULL)                                                 \
139                 return WIMLIB_ERR_ICONV_NOT_AVAILABLE;                  \
140                                                                         \
141         chartype2 *buf;                                                 \
142         size_t bufsize;                                                 \
143         bool buf_onheap;                                                \
144         bufsize = (worst_case_len_expr) * sizeof(chartype2);            \
145         /* Worst case length */                                         \
146         if (bufsize <= STACK_MAX) {                                     \
147                 buf = alloca(bufsize);                                  \
148                 buf_onheap = false;                                     \
149         } else {                                                        \
150                 buf = MALLOC(bufsize);                                  \
151                 if (!buf)                                               \
152                         return WIMLIB_ERR_NOMEM;                        \
153                 buf_onheap = true;                                      \
154         }                                                               \
155                                                                         \
156         char *inbuf = (char*)in;                                        \
157         size_t inbytesleft = in_nbytes;                                 \
158         char *outbuf = (char*)buf;                                      \
159         size_t outbytesleft = bufsize;                                  \
160         size_t len;                                                     \
161         int ret;                                                        \
162                                                                         \
163         len = iconv(*cd, &inbuf, &inbytesleft, &outbuf, &outbytesleft); \
164         if (len == (size_t)-1) {                                        \
165                 err_msg;                                                \
166                 ret = err_return;                                       \
167         } else {                                                        \
168                 *out_nbytes_ret = bufsize - outbytesleft;               \
169                 ret = 0;                                                \
170         }                                                               \
171         put_iconv(cd);                                                  \
172         if (buf_onheap)                                                 \
173                 FREE(buf);                                              \
174         return ret;                                                     \
175 }                                                                       \
176                                                                         \
177 modifier int                                                            \
178 varname1##_to_##varname2##_buf(const chartype1 *in, size_t in_nbytes,   \
179                                chartype2 *out)                          \
180 {                                                                       \
181         iconv_t *cd = get_iconv(&iconv_##varname1##_to_##varname2);     \
182         if (cd == NULL)                                                 \
183                 return WIMLIB_ERR_ICONV_NOT_AVAILABLE;                  \
184                                                                         \
185         char *inbuf = (char*)in;                                        \
186         size_t inbytesleft = in_nbytes;                                 \
187         char *outbuf = (char*)out;                                      \
188         const size_t LARGE_NUMBER = 1000000000;                         \
189         size_t outbytesleft = LARGE_NUMBER;                             \
190         size_t len;                                                     \
191         int ret;                                                        \
192                                                                         \
193         len = iconv(*cd, &inbuf, &inbytesleft, &outbuf, &outbytesleft); \
194         if (len == (size_t)-1) {                                        \
195                 err_msg;                                                \
196                 ret = err_return;                                       \
197         } else {                                                        \
198                 out[(LARGE_NUMBER-outbytesleft)/sizeof(chartype2)] = 0; \
199                 ret = 0;                                                \
200         }                                                               \
201         put_iconv(cd);                                                  \
202         return ret;                                                     \
203 }                                                                       \
204                                                                         \
205 modifier int                                                            \
206 varname1##_to_##varname2(const chartype1 *in, size_t in_nbytes,         \
207                          chartype2 **out_ret,                           \
208                          size_t *out_nbytes_ret)                        \
209 {                                                                       \
210         int ret;                                                        \
211         chartype2 *out;                                                 \
212         size_t out_nbytes;                                              \
213                                                                         \
214         if (earlyreturn_on_utf8_locale && wimlib_mbs_is_utf8) {         \
215                 earlyreturn_expr;                                       \
216                 /* Out same as in */                                    \
217                 out = MALLOC(in_nbytes + sizeof(chartype2));            \
218                 if (!out)                                               \
219                         return WIMLIB_ERR_NOMEM;                        \
220                 memcpy(out, in, in_nbytes);                             \
221                 out[in_nbytes / sizeof(chartype2)] = 0;                 \
222                 *out_ret = out;                                         \
223                 *out_nbytes_ret = in_nbytes;                            \
224                 return 0;                                               \
225         }                                                               \
226                                                                         \
227         ret = varname1##_to_##varname2##_nbytes(in, in_nbytes,          \
228                                                 &out_nbytes);           \
229         if (ret)                                                        \
230                 return ret;                                             \
231                                                                         \
232         out = MALLOC(out_nbytes + sizeof(chartype2));                   \
233         if (!out)                                                       \
234                 return WIMLIB_ERR_NOMEM;                                \
235                                                                         \
236         ret = varname1##_to_##varname2##_buf(in, in_nbytes, out);       \
237         if (ret) {                                                      \
238                 FREE(out);                                              \
239         } else {                                                        \
240                 *out_ret = out;                                         \
241                 *out_nbytes_ret = out_nbytes;                           \
242         }                                                               \
243         return ret;                                                     \
244 }
245
246 #if !TCHAR_IS_UTF16LE
247
248 /* UNIX */
249
250 DEFINE_CHAR_CONVERSION_FUNCTIONS(utf8, "UTF-8", tchar,
251                                  utf16le, "UTF-16LE", utf16lechar,
252                                  false,
253                                  ,
254                                  in_nbytes * 2,
255                                  WIMLIB_ERR_INVALID_UTF8_STRING,
256                                  ERROR_WITH_ERRNO("Failed to convert UTF-8 string "
257                                                   "to UTF-16LE string!"),
258                                  static)
259
260 DEFINE_CHAR_CONVERSION_FUNCTIONS(utf16le, "UTF-16LE", utf16lechar,
261                                  utf8, "UTF-8", tchar,
262                                  false,
263                                  ,
264                                  in_nbytes * 2,
265                                  WIMLIB_ERR_INVALID_UTF16_STRING,
266                                  ERROR_WITH_ERRNO("Failed to convert UTF-16LE string "
267                                                   "to UTF-8 string!"),
268                                  static)
269
270 DEFINE_CHAR_CONVERSION_FUNCTIONS(tstr, "", tchar,
271                                  utf16le, "UTF-16LE", utf16lechar,
272                                  true,
273                                  return utf8_to_utf16le(in, in_nbytes, out_ret, out_nbytes_ret),
274                                  in_nbytes * 2,
275                                  WIMLIB_ERR_INVALID_MULTIBYTE_STRING,
276                                  ERROR_WITH_ERRNO("Failed to convert multibyte "
277                                                   "string \"%"TS"\" to UTF-16LE string!", in);
278                                  ERROR("If the data you provided was UTF-8, please make sure "
279                                        "the character encoding\n"
280                                        "        of your current locale is UTF-8."),
281                                  )
282
283 DEFINE_CHAR_CONVERSION_FUNCTIONS(utf16le, "UTF-16LE", utf16lechar,
284                                  tstr, "", tchar,
285                                  true,
286                                  return utf16le_to_utf8(in, in_nbytes, out_ret, out_nbytes_ret),
287                                  in_nbytes * 2,
288                                  WIMLIB_ERR_UNICODE_STRING_NOT_REPRESENTABLE,
289                                  ERROR("Failed to convert UTF-16LE string to "
290                                        "multibyte string!");
291                                  ERROR("This may be because the UTF-16LE string "
292                                        "could not be represented\n"
293                                        "        in your locale's character encoding."),
294                                  )
295 #endif
296
297 /* tchar to UTF-8 and back */
298 #if TCHAR_IS_UTF16LE
299
300 /* Windows */
301 DEFINE_CHAR_CONVERSION_FUNCTIONS(tstr, "UTF-16LE", tchar,
302                                  utf8, "UTF-8", char,
303                                  false,
304                                  ,
305                                  in_nbytes * 2,
306                                  WIMLIB_ERR_INVALID_UTF16_STRING,
307                                  ERROR_WITH_ERRNO("Failed to convert UTF-16LE "
308                                                   "string \"%"TS"\" to UTF-8 string!", in),
309                                  )
310
311 DEFINE_CHAR_CONVERSION_FUNCTIONS(utf8, "UTF-8", char,
312                                  tstr, "UTF-16LE", tchar,
313                                  false,
314                                  ,
315                                  in_nbytes * 2,
316                                  WIMLIB_ERR_INVALID_UTF8_STRING,
317                                  ERROR_WITH_ERRNO("Failed to convert UTF-8 string "
318                                                   "to UTF-16LE string!"),
319                                  )
320 #else
321
322 /* UNIX */
323
324 DEFINE_CHAR_CONVERSION_FUNCTIONS(tstr, "", tchar,
325                                  utf8, "UTF-8", char,
326                                  true,
327                                  ,
328                                  in_nbytes * 4,
329                                  WIMLIB_ERR_INVALID_MULTIBYTE_STRING,
330                                  ERROR_WITH_ERRNO("Failed to convert multibyte "
331                                                   "string \"%"TS"\" to UTF-8 string!", in);
332                                  ERROR("If the data you provided was UTF-8, please make sure "
333                                        "the character\n"
334                                        "        encoding of your current locale is UTF-8."),
335                                  )
336
337 DEFINE_CHAR_CONVERSION_FUNCTIONS(utf8, "UTF-8", char,
338                                  tstr, "", tchar,
339                                  true,
340                                  ,
341                                  in_nbytes * 4,
342                                  WIMLIB_ERR_UNICODE_STRING_NOT_REPRESENTABLE,
343                                  ERROR("Failed to convert UTF-8 string to "
344                                        "multibyte string!");
345                                  ERROR("This may be because the UTF-8 data "
346                                        "could not be represented\n"
347                                        "        in your locale's character encoding."),
348                                  )
349 #endif
350
351 int
352 tstr_to_utf8_simple(const tchar *tstr, char **out)
353 {
354         size_t out_nbytes;
355         return tstr_to_utf8(tstr, tstrlen(tstr) * sizeof(tchar),
356                             out, &out_nbytes);
357 }
358
359 int
360 utf8_to_tstr_simple(const char *utf8str, tchar **out)
361 {
362         size_t out_nbytes;
363         return utf8_to_tstr(utf8str, strlen(utf8str), out, &out_nbytes);
364 }
365
366 static void
367 iconv_cleanup(struct iconv_list_head *head)
368 {
369         pthread_mutex_destroy(&head->mutex);
370         while (!list_empty(&head->list)) {
371                 struct iconv_node *i;
372
373                 i = container_of(head->list.next, struct iconv_node, list);
374                 list_del(&i->list);
375                 iconv_close(i->cd);
376                 FREE(i);
377         }
378 }
379
380 void
381 iconv_global_cleanup(void)
382 {
383         iconv_cleanup(&iconv_utf8_to_tstr);
384         iconv_cleanup(&iconv_tstr_to_utf8);
385 #if !TCHAR_IS_UTF16LE
386         iconv_cleanup(&iconv_utf16le_to_tstr);
387         iconv_cleanup(&iconv_tstr_to_utf16le);
388         iconv_cleanup(&iconv_utf16le_to_utf8);
389         iconv_cleanup(&iconv_utf8_to_utf16le);
390 #endif
391 }
392
393 /* A table that maps from UCS-2 characters to their upper case equivalents.
394  * Index and array values are both CPU endian.
395  * Note: this is only an *approximation* of real UTF-16 case folding.
396  */
397 static u16 upcase[65536];
398
399 /*
400  * Initialize the 'upcase' table.
401  *
402  * Code modified from NTFS-3g, original copyright notices below:
403  *
404  * Copyright (c) 2000-2004 Anton Altaparmakov
405  * Copyright (c) 2002-2009 Szabolcs Szakacsits
406  * Copyright (c) 2008-2011 Jean-Pierre Andre
407  * Copyright (c) 2008      Bernhard Kaindl
408  *
409  * License GPLv2 or later.
410  *
411  * The expanded table itself is the same as that used by Windows Vista for
412  * NTFS case insensitivity.
413  */
414 void
415 init_upcase(void)
416 {
417         /*
418          *      This is the table as defined by Vista
419          */
420         /*
421          * "Start" is inclusive and "End" is exclusive, every value has the
422          * value of "Add" added to it.
423          */
424         static const u16 uc_run_table[][3] = { /* Start, End, Add */
425         {0x0061, 0x007b,   -32}, {0x00e0, 0x00f7,  -32}, {0x00f8, 0x00ff, -32},
426         {0x0256, 0x0258,  -205}, {0x028a, 0x028c, -217}, {0x037b, 0x037e, 130},
427         {0x03ac, 0x03ad,   -38}, {0x03ad, 0x03b0,  -37}, {0x03b1, 0x03c2, -32},
428         {0x03c2, 0x03c3,   -31}, {0x03c3, 0x03cc,  -32}, {0x03cc, 0x03cd, -64},
429         {0x03cd, 0x03cf,   -63}, {0x0430, 0x0450,  -32}, {0x0450, 0x0460, -80},
430         {0x0561, 0x0587,   -48}, {0x1f00, 0x1f08,    8}, {0x1f10, 0x1f16,   8},
431         {0x1f20, 0x1f28,     8}, {0x1f30, 0x1f38,    8}, {0x1f40, 0x1f46,   8},
432         {0x1f51, 0x1f52,     8}, {0x1f53, 0x1f54,    8}, {0x1f55, 0x1f56,   8},
433         {0x1f57, 0x1f58,     8}, {0x1f60, 0x1f68,    8}, {0x1f70, 0x1f72,  74},
434         {0x1f72, 0x1f76,    86}, {0x1f76, 0x1f78,  100}, {0x1f78, 0x1f7a, 128},
435         {0x1f7a, 0x1f7c,   112}, {0x1f7c, 0x1f7e,  126}, {0x1f80, 0x1f88,   8},
436         {0x1f90, 0x1f98,     8}, {0x1fa0, 0x1fa8,    8}, {0x1fb0, 0x1fb2,   8},
437         {0x1fb3, 0x1fb4,     9}, {0x1fcc, 0x1fcd,   -9}, {0x1fd0, 0x1fd2,   8},
438         {0x1fe0, 0x1fe2,     8}, {0x1fe5, 0x1fe6,    7}, {0x1ffc, 0x1ffd,  -9},
439         {0x2170, 0x2180,   -16}, {0x24d0, 0x24ea,  -26}, {0x2c30, 0x2c5f, -48},
440         {0x2d00, 0x2d26, -7264}, {0xff41, 0xff5b,  -32},
441         };
442         /*
443          * "Start" is exclusive and "End" is inclusive, every second value is
444          * decremented by one.
445          */
446         static const u16 uc_dup_table[][2] = { /* Start, End */
447         {0x0100, 0x012f}, {0x0132, 0x0137}, {0x0139, 0x0149}, {0x014a, 0x0178},
448         {0x0179, 0x017e}, {0x01a0, 0x01a6}, {0x01b3, 0x01b7}, {0x01cd, 0x01dd},
449         {0x01de, 0x01ef}, {0x01f4, 0x01f5}, {0x01f8, 0x01f9}, {0x01fa, 0x0220},
450         {0x0222, 0x0234}, {0x023b, 0x023c}, {0x0241, 0x0242}, {0x0246, 0x024f},
451         {0x03d8, 0x03ef}, {0x03f7, 0x03f8}, {0x03fa, 0x03fb}, {0x0460, 0x0481},
452         {0x048a, 0x04bf}, {0x04c1, 0x04c4}, {0x04c5, 0x04c8}, {0x04c9, 0x04ce},
453         {0x04ec, 0x04ed}, {0x04d0, 0x04eb}, {0x04ee, 0x04f5}, {0x04f6, 0x0513},
454         {0x1e00, 0x1e95}, {0x1ea0, 0x1ef9}, {0x2183, 0x2184}, {0x2c60, 0x2c61},
455         {0x2c67, 0x2c6c}, {0x2c75, 0x2c76}, {0x2c80, 0x2ce3},
456         };
457         /*
458          * Set the Unicode character at offset "Offset" to "Value".  Note,
459          * "Value" is host endian.
460          */
461         static const u16 uc_byte_table[][2] = { /* Offset, Value */
462         {0x00ff, 0x0178}, {0x0180, 0x0243}, {0x0183, 0x0182}, {0x0185, 0x0184},
463         {0x0188, 0x0187}, {0x018c, 0x018b}, {0x0192, 0x0191}, {0x0195, 0x01f6},
464         {0x0199, 0x0198}, {0x019a, 0x023d}, {0x019e, 0x0220}, {0x01a8, 0x01a7},
465         {0x01ad, 0x01ac}, {0x01b0, 0x01af}, {0x01b9, 0x01b8}, {0x01bd, 0x01bc},
466         {0x01bf, 0x01f7}, {0x01c6, 0x01c4}, {0x01c9, 0x01c7}, {0x01cc, 0x01ca},
467         {0x01dd, 0x018e}, {0x01f3, 0x01f1}, {0x023a, 0x2c65}, {0x023e, 0x2c66},
468         {0x0253, 0x0181}, {0x0254, 0x0186}, {0x0259, 0x018f}, {0x025b, 0x0190},
469         {0x0260, 0x0193}, {0x0263, 0x0194}, {0x0268, 0x0197}, {0x0269, 0x0196},
470         {0x026b, 0x2c62}, {0x026f, 0x019c}, {0x0272, 0x019d}, {0x0275, 0x019f},
471         {0x027d, 0x2c64}, {0x0280, 0x01a6}, {0x0283, 0x01a9}, {0x0288, 0x01ae},
472         {0x0289, 0x0244}, {0x028c, 0x0245}, {0x0292, 0x01b7}, {0x03f2, 0x03f9},
473         {0x04cf, 0x04c0}, {0x1d7d, 0x2c63}, {0x214e, 0x2132},
474         };
475
476         for (u32 i = 0; i < 65536; i++)
477                 upcase[i] = i;
478
479         for (u32 r = 0; r < ARRAY_LEN(uc_run_table); r++)
480                 for (u32 i = uc_run_table[r][0]; i < uc_run_table[r][1]; i++)
481                         upcase[i] = i + uc_run_table[r][2];
482
483         for (u32 r = 0; r < ARRAY_LEN(uc_dup_table); r++)
484                 for (u32 i = uc_dup_table[r][0]; i < uc_dup_table[r][1]; i += 2)
485                         upcase[i + 1] = i;
486
487         for (u32 r = 0; r < ARRAY_LEN(uc_byte_table); r++)
488                 upcase[uc_byte_table[r][0]] = uc_byte_table[r][1];
489
490 #if 0
491         /* Sanity checks  */
492         wimlib_assert(upcase['a'] == 'A');
493         wimlib_assert(upcase['A'] == 'A');
494         wimlib_assert(upcase['z'] == 'Z');
495         wimlib_assert(upcase['Z'] == 'Z');
496         wimlib_assert(upcase['1'] == '1');
497         wimlib_assert(upcase[0x00e9] == 0x00c9); /* Latin letter e, with acute accent  */
498         wimlib_assert(upcase[0x00c9] == 0x00c9);
499         wimlib_assert(upcase[0x03c1] == 0x03a1); /* Greek letter rho  */
500         wimlib_assert(upcase[0x03a1] == 0x03a1);
501         wimlib_assert(upcase[0x0436] == 0x0416); /* Cyrillic letter zhe  */
502         wimlib_assert(upcase[0x0416] == 0x0416);
503         wimlib_assert(upcase[0x0567] == 0x0537); /* Armenian letter eh  */
504         wimlib_assert(upcase[0x0537] == 0x0537);
505         wimlib_assert(upcase[0x24d0] == 0x24b6); /* Circled Latin letter A
506                                                     (is that a real character???)  */
507         wimlib_assert(upcase[0x24b6] == 0x24b6);
508         wimlib_assert(upcase[0x2603] == 0x2603); /* Note to self: Upper case
509                                                     snowman symbol does not
510                                                     exist.  */
511 #endif
512 }
513
514 /* Compare UTF-16LE strings case-sensitively (%ignore_case == false) or
515  * case-insensitively (%ignore_case == true).
516  *
517  * This is implemented using the default upper-case table used by NTFS.  It does
518  * not handle all possible cases allowed by UTF-16LE.  For example, different
519  * normalizations of the same sequence of "characters" are not considered equal.
520  * It hopefully does the right thing most of the time though.  */
521 int
522 cmp_utf16le_strings(const utf16lechar *s1, size_t n1,
523                     const utf16lechar *s2, size_t n2,
524                     bool ignore_case)
525 {
526         size_t n = min(n1, n2);
527
528         if (ignore_case) {
529                 for (size_t i = 0; i < n; i++) {
530                         u16 c1 = upcase[le16_to_cpu(s1[i])];
531                         u16 c2 = upcase[le16_to_cpu(s2[i])];
532                         if (c1 != c2)
533                                 return (c1 < c2) ? -1 : 1;
534                 }
535         } else {
536                 for (size_t i = 0; i < n; i++) {
537                         u16 c1 = le16_to_cpu(s1[i]);
538                         u16 c2 = le16_to_cpu(s2[i]);
539                         if (c1 != c2)
540                                 return (c1 < c2) ? -1 : 1;
541                 }
542         }
543         if (n1 == n2)
544                 return 0;
545         return (n1 < n2) ? -1 : 1;
546 }
547
548 /* Duplicate a UTF16-LE string which may not be null-terminated.  */
549 utf16lechar *
550 utf16le_dupz(const utf16lechar *ustr, size_t usize)
551 {
552         utf16lechar *dup = MALLOC(usize + sizeof(utf16lechar));
553         if (dup) {
554                 memcpy(dup, ustr, usize);
555                 dup[usize / sizeof(utf16lechar)] = 0;
556         }
557         return dup;
558 }