Files @ r20075:2bda14adc373
Branch filter:

Location: cpp/openttd-patchpack/source/src/string.cpp

rubidium
(svn r25038) -Fix [FS#5479]: minimise gaps feature caused removal to only happen at the signal build interval instead of the implicit interval of 1
  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
/* $Id$ */

/*
 * This file is part of OpenTTD.
 * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
 * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
 */

/** @file string.cpp Handling of C-type strings (char*). */

#include "stdafx.h"
#include "debug.h"
#include "core/alloc_func.hpp"
#include "core/math_func.hpp"
#include "string_func.h"

#include "table/control_codes.h"

#include <stdarg.h>
#include <ctype.h> /* required for tolower() */

#ifdef _MSC_VER
#include <errno.h> // required by vsnprintf implementation for MSVC
#endif

#ifdef WITH_ICU
/* Required by strnatcmp. */
#include <unicode/ustring.h>
#include "language.h"
#include "gfx_func.h"
#endif /* WITH_ICU */

/**
 * Safer implementation of vsnprintf; same as vsnprintf except:
 * - last instead of size, i.e. replace sizeof with lastof.
 * - return gives the amount of characters added, not what it would add.
 * @param str    buffer to write to up to last
 * @param last   last character we may write to
 * @param format the formatting (see snprintf)
 * @param ap     the list of arguments for the format
 * @return the number of added characters
 */
static int CDECL vseprintf(char *str, const char *last, const char *format, va_list ap)
{
	ptrdiff_t diff = last - str;
	if (diff < 0) return 0;
	return min((int)diff, vsnprintf(str, diff + 1, format, ap));
}

/**
 * Appends characters from one string to another.
 *
 * Appends the source string to the destination string with respect of the
 * terminating null-character and the maximum size of the destination
 * buffer.
 *
 * @note usage ttd_strlcat(dst, src, lengthof(dst));
 * @note lengthof() applies only to fixed size arrays
 *
 * @param dst The buffer containing the target string
 * @param src The buffer containing the string to append
 * @param size The maximum size of the destination buffer
 */
void ttd_strlcat(char *dst, const char *src, size_t size)
{
	assert(size > 0);
	while (size > 0 && *dst != '\0') {
		size--;
		dst++;
	}

	ttd_strlcpy(dst, src, size);
}


/**
 * Copies characters from one buffer to another.
 *
 * Copies the source string to the destination buffer with respect of the
 * terminating null-character and the maximum size of the destination
 * buffer.
 *
 * @note usage ttd_strlcpy(dst, src, lengthof(dst));
 * @note lengthof() applies only to fixed size arrays
 *
 * @param dst The destination buffer
 * @param src The buffer containing the string to copy
 * @param size The maximum size of the destination buffer
 */
void ttd_strlcpy(char *dst, const char *src, size_t size)
{
	assert(size > 0);
	while (--size > 0 && *src != '\0') {
		*dst++ = *src++;
	}
	*dst = '\0';
}


/**
 * Appends characters from one string to another.
 *
 * Appends the source string to the destination string with respect of the
 * terminating null-character and and the last pointer to the last element
 * in the destination buffer. If the last pointer is set to NULL no
 * boundary check is performed.
 *
 * @note usage: strecat(dst, src, lastof(dst));
 * @note lastof() applies only to fixed size arrays
 *
 * @param dst The buffer containing the target string
 * @param src The buffer containing the string to append
 * @param last The pointer to the last element of the destination buffer
 * @return The pointer to the terminating null-character in the destination buffer
 */
char *strecat(char *dst, const char *src, const char *last)
{
	assert(dst <= last);
	while (*dst != '\0') {
		if (dst == last) return dst;
		dst++;
	}

	return strecpy(dst, src, last);
}


/**
 * Copies characters from one buffer to another.
 *
 * Copies the source string to the destination buffer with respect of the
 * terminating null-character and the last pointer to the last element in
 * the destination buffer. If the last pointer is set to NULL no boundary
 * check is performed.
 *
 * @note usage: strecpy(dst, src, lastof(dst));
 * @note lastof() applies only to fixed size arrays
 *
 * @param dst The destination buffer
 * @param src The buffer containing the string to copy
 * @param last The pointer to the last element of the destination buffer
 * @return The pointer to the terminating null-character in the destination buffer
 */
char *strecpy(char *dst, const char *src, const char *last)
{
	assert(dst <= last);
	while (dst != last && *src != '\0') {
		*dst++ = *src++;
	}
	*dst = '\0';

	if (dst == last && *src != '\0') {
#if defined(STRGEN) || defined(SETTINGSGEN)
		error("String too long for destination buffer");
#else /* STRGEN || SETTINGSGEN */
		DEBUG(misc, 0, "String too long for destination buffer");
#endif /* STRGEN || SETTINGSGEN */
	}
	return dst;
}

/**
 * Format, "printf", into a newly allocated string.
 * @param str The formatting string.
 * @return The formatted string. You must free this!
 */
char *CDECL str_fmt(const char *str, ...)
{
	char buf[4096];
	va_list va;

	va_start(va, str);
	int len = vseprintf(buf, lastof(buf), str, va);
	va_end(va);
	char *p = MallocT<char>(len + 1);
	memcpy(p, buf, len + 1);
	return p;
}

/**
 * Scan the string for old values of SCC_ENCODED and fix it to
 * it's new, static value.
 * @param str the string to scan
 * @param last the last valid character of str
 */
void str_fix_scc_encoded(char *str, const char *last)
{
	while (str <= last && *str != '\0') {
		size_t len = Utf8EncodedCharLen(*str);
		if ((len == 0 && str + 4 > last) || str + len > last) break;

		WChar c;
		len = Utf8Decode(&c, str);
		if (c == '\0') break;

		if (c == 0xE028 || c == 0xE02A) {
			c = SCC_ENCODED;
		}
		str += Utf8Encode(str, c);
	}
	*str = '\0';
}


/**
 * Scans the string for valid characters and if it finds invalid ones,
 * replaces them with a question mark '?' (if not ignored)
 * @param str the string to validate
 * @param last the last valid character of str
 * @param settings the settings for the string validation.
 */
void str_validate(char *str, const char *last, StringValidationSettings settings)
{
	/* Assume the ABSOLUTE WORST to be in str as it comes from the outside. */

	char *dst = str;
	while (str <= last && *str != '\0') {
		size_t len = Utf8EncodedCharLen(*str);
		/* If the character is unknown, i.e. encoded length is 0
		 * we assume worst case for the length check.
		 * The length check is needed to prevent Utf8Decode to read
		 * over the terminating '\0' if that happens to be placed
		 * within the encoding of an UTF8 character. */
		if ((len == 0 && str + 4 > last) || str + len > last) break;

		WChar c;
		len = Utf8Decode(&c, str);
		/* It's possible to encode the string termination character
		 * into a multiple bytes. This prevents those termination
		 * characters to be skipped */
		if (c == '\0') break;

		if ((IsPrintable(c) && (c < SCC_SPRITE_START || c > SCC_SPRITE_END)) || ((settings & SVS_ALLOW_CONTROL_CODE) != 0 && c == SCC_ENCODED)) {
			/* Copy the character back. Even if dst is current the same as str
			 * (i.e. no characters have been changed) this is quicker than
			 * moving the pointers ahead by len */
			do {
				*dst++ = *str++;
			} while (--len != 0);
		} else if ((settings & SVS_ALLOW_NEWLINE) != 0  && c == '\n') {
			*dst++ = *str++;
		} else {
			if ((settings & SVS_ALLOW_NEWLINE) != 0 && c == '\r' && str[1] == '\n') {
				str += len;
				continue;
			}
			/* Replace the undesirable character with a question mark */
			str += len;
			if ((settings & SVS_REPLACE_WITH_QUESTION_MARK) != 0) *dst++ = '?';

			/* In case of these two special cases assume that they really
			 * mean SETX/SETXY and also "eat" the parameter. If this was
			 * not the case the string was broken to begin with and this
			 * would not break much more. */
			if (c == SCC_SETX) {
				str++;
			} else if (c == SCC_SETXY) {
				str += 2;
			}
		}
	}

	*dst = '\0';
}

/**
 * Checks whether the given string is valid, i.e. contains only
 * valid (printable) characters and is properly terminated.
 * @param str  The string to validate.
 * @param last The last character of the string, i.e. the string
 *             must be terminated here or earlier.
 */
bool StrValid(const char *str, const char *last)
{
	/* Assume the ABSOLUTE WORST to be in str as it comes from the outside. */

	while (str <= last && *str != '\0') {
		size_t len = Utf8EncodedCharLen(*str);
		/* Encoded length is 0 if the character isn't known.
		 * The length check is needed to prevent Utf8Decode to read
		 * over the terminating '\0' if that happens to be placed
		 * within the encoding of an UTF8 character. */
		if (len == 0 || str + len > last) return false;

		WChar c;
		len = Utf8Decode(&c, str);
		if (!IsPrintable(c) || (c >= SCC_SPRITE_START && c <= SCC_SPRITE_END)) {
			return false;
		}

		str += len;
	}

	return *str == '\0';
}

/** Scans the string for colour codes and strips them */
void str_strip_colours(char *str)
{
	char *dst = str;
	WChar c;
	size_t len;

	for (len = Utf8Decode(&c, str); c != '\0'; len = Utf8Decode(&c, str)) {
		if (c < SCC_BLUE || c > SCC_BLACK) {
			/* Copy the character back. Even if dst is current the same as str
			 * (i.e. no characters have been changed) this is quicker than
			 * moving the pointers ahead by len */
			do {
				*dst++ = *str++;
			} while (--len != 0);
		} else {
			/* Just skip (strip) the colour codes */
			str += len;
		}
	}
	*dst = '\0';
}

/**
 * Get the length of an UTF-8 encoded string in number of characters
 * and thus not the number of bytes that the encoded string contains.
 * @param s The string to get the length for.
 * @return The length of the string in characters.
 */
size_t Utf8StringLength(const char *s)
{
	size_t len = 0;
	const char *t = s;
	while (Utf8Consume(&t) != 0) len++;
	return len;
}


/**
 * Convert a given ASCII string to lowercase.
 * NOTE: only support ASCII characters, no UTF8 fancy. As currently
 * the function is only used to lowercase data-filenames if they are
 * not found, this is sufficient. If more, or general functionality is
 * needed, look to r7271 where it was removed because it was broken when
 * using certain locales: eg in Turkish the uppercase 'I' was converted to
 * '?', so just revert to the old functionality
 * @param str string to convert
 * @return String has changed.
 */
bool strtolower(char *str)
{
	bool changed = false;
	for (; *str != '\0'; str++) {
		char new_str = tolower(*str);
		changed |= new_str != *str;
		*str = new_str;
	}
	return changed;
}

/**
 * Only allow certain keys. You can define the filter to be used. This makes
 *  sure no invalid keys can get into an editbox, like BELL.
 * @param key character to be checked
 * @param afilter the filter to use
 * @return true or false depending if the character is printable/valid or not
 */
bool IsValidChar(WChar key, CharSetFilter afilter)
{
	switch (afilter) {
		case CS_ALPHANUMERAL:  return IsPrintable(key);
		case CS_NUMERAL:       return (key >= '0' && key <= '9');
		case CS_NUMERAL_SPACE: return (key >= '0' && key <= '9') || key == ' ';
		case CS_ALPHA:         return IsPrintable(key) && !(key >= '0' && key <= '9');
		case CS_HEXADECIMAL:   return (key >= '0' && key <= '9') || (key >= 'a' && key <= 'f') || (key >= 'A' && key <= 'F');
	}

	return false;
}

#ifdef WIN32
/* Since version 3.14, MinGW Runtime has snprintf() and vsnprintf() conform to C99 but it's not the case for older versions */
#if (__MINGW32_MAJOR_VERSION < 3) || ((__MINGW32_MAJOR_VERSION == 3) && (__MINGW32_MINOR_VERSION < 14))
int CDECL snprintf(char *str, size_t size, const char *format, ...)
{
	va_list ap;
	int ret;

	va_start(ap, format);
	ret = vsnprintf(str, size, format, ap);
	va_end(ap);
	return ret;
}
#endif /* MinGW Runtime < 3.14 */

#ifdef _MSC_VER
/**
 * Almost POSIX compliant implementation of \c vsnprintf for VC compiler.
 * The difference is in the value returned on output truncation. This
 * implementation returns size whereas a POSIX implementation returns
 * size or more (the number of bytes that would be written to str
 * had size been sufficiently large excluding the terminating null byte).
 */
int CDECL vsnprintf(char *str, size_t size, const char *format, va_list ap)
{
	if (size == 0) return 0;

	errno = 0;
	int ret = _vsnprintf(str, size, format, ap);

	if (ret < 0) {
		if (errno != ERANGE) {
			/* There's a formatting error, better get that looked
			 * at properly instead of ignoring it. */
			NOT_REACHED();
		}
	} else if ((size_t)ret < size) {
		/* The buffer is big enough for the number of
		 * characters stored (excluding null), i.e.
		 * the string has been null-terminated. */
		return ret;
	}

	/* The buffer is too small for _vsnprintf to write the
	 * null-terminator at its end and return size. */
	str[size - 1] = '\0';
	return (int)size;
}
#endif /* _MSC_VER */

#endif /* WIN32 */

/**
 * Safer implementation of snprintf; same as snprintf except:
 * - last instead of size, i.e. replace sizeof with lastof.
 * - return gives the amount of characters added, not what it would add.
 * @param str    buffer to write to up to last
 * @param last   last character we may write to
 * @param format the formatting (see snprintf)
 * @return the number of added characters
 */
int CDECL seprintf(char *str, const char *last, const char *format, ...)
{
	va_list ap;

	va_start(ap, format);
	int ret = vseprintf(str, last, format, ap);
	va_end(ap);
	return ret;
}


/**
 * Convert the md5sum to a hexadecimal string representation
 * @param buf buffer to put the md5sum into
 * @param last last character of buffer (usually lastof(buf))
 * @param md5sum the md5sum itself
 * @return a pointer to the next character after the md5sum
 */
char *md5sumToString(char *buf, const char *last, const uint8 md5sum[16])
{
	char *p = buf;

	for (uint i = 0; i < 16; i++) {
		p += seprintf(p, last, "%02X", md5sum[i]);
	}

	return p;
}


/* UTF-8 handling routines */


/**
 * Decode and consume the next UTF-8 encoded character.
 * @param c Buffer to place decoded character.
 * @param s Character stream to retrieve character from.
 * @return Number of characters in the sequence.
 */
size_t Utf8Decode(WChar *c, const char *s)
{
	assert(c != NULL);

	if (!HasBit(s[0], 7)) {
		/* Single byte character: 0xxxxxxx */
		*c = s[0];
		return 1;
	} else if (GB(s[0], 5, 3) == 6) {
		if (IsUtf8Part(s[1])) {
			/* Double byte character: 110xxxxx 10xxxxxx */
			*c = GB(s[0], 0, 5) << 6 | GB(s[1], 0, 6);
			if (*c >= 0x80) return 2;
		}
	} else if (GB(s[0], 4, 4) == 14) {
		if (IsUtf8Part(s[1]) && IsUtf8Part(s[2])) {
			/* Triple byte character: 1110xxxx 10xxxxxx 10xxxxxx */
			*c = GB(s[0], 0, 4) << 12 | GB(s[1], 0, 6) << 6 | GB(s[2], 0, 6);
			if (*c >= 0x800) return 3;
		}
	} else if (GB(s[0], 3, 5) == 30) {
		if (IsUtf8Part(s[1]) && IsUtf8Part(s[2]) && IsUtf8Part(s[3])) {
			/* 4 byte character: 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx */
			*c = GB(s[0], 0, 3) << 18 | GB(s[1], 0, 6) << 12 | GB(s[2], 0, 6) << 6 | GB(s[3], 0, 6);
			if (*c >= 0x10000 && *c <= 0x10FFFF) return 4;
		}
	}

	/* DEBUG(misc, 1, "[utf8] invalid UTF-8 sequence"); */
	*c = '?';
	return 1;
}


/**
 * Encode a unicode character and place it in the buffer.
 * @param buf Buffer to place character.
 * @param c   Unicode character to encode.
 * @return Number of characters in the encoded sequence.
 */
size_t Utf8Encode(char *buf, WChar c)
{
	if (c < 0x80) {
		*buf = c;
		return 1;
	} else if (c < 0x800) {
		*buf++ = 0xC0 + GB(c,  6, 5);
		*buf   = 0x80 + GB(c,  0, 6);
		return 2;
	} else if (c < 0x10000) {
		*buf++ = 0xE0 + GB(c, 12, 4);
		*buf++ = 0x80 + GB(c,  6, 6);
		*buf   = 0x80 + GB(c,  0, 6);
		return 3;
	} else if (c < 0x110000) {
		*buf++ = 0xF0 + GB(c, 18, 3);
		*buf++ = 0x80 + GB(c, 12, 6);
		*buf++ = 0x80 + GB(c,  6, 6);
		*buf   = 0x80 + GB(c,  0, 6);
		return 4;
	}

	/* DEBUG(misc, 1, "[utf8] can't UTF-8 encode value 0x%X", c); */
	*buf = '?';
	return 1;
}

/**
 * Properly terminate an UTF8 string to some maximum length
 * @param s string to check if it needs additional trimming
 * @param maxlen the maximum length the buffer can have.
 * @return the new length in bytes of the string (eg. strlen(new_string))
 * @note maxlen is the string length _INCLUDING_ the terminating '\0'
 */
size_t Utf8TrimString(char *s, size_t maxlen)
{
	size_t length = 0;

	for (const char *ptr = strchr(s, '\0'); *s != '\0';) {
		size_t len = Utf8EncodedCharLen(*s);
		/* Silently ignore invalid UTF8 sequences, our only concern trimming */
		if (len == 0) len = 1;

		/* Take care when a hard cutoff was made for the string and
		 * the last UTF8 sequence is invalid */
		if (length + len >= maxlen || (s + len > ptr)) break;
		s += len;
		length += len;
	}

	*s = '\0';
	return length;
}

#ifdef DEFINE_STRNDUP
#include "core/math_func.hpp"
char *strndup(const char *s, size_t len)
{
	len = min(strlen(s), len);
	char *tmp = CallocT<char>(len + 1);
	memcpy(tmp, s, len);
	return tmp;
}
#endif /* DEFINE_STRNDUP */

#ifdef DEFINE_STRCASESTR
char *strcasestr(const char *haystack, const char *needle)
{
	size_t hay_len = strlen(haystack);
	size_t needle_len = strlen(needle);
	while (hay_len >= needle_len) {
		if (strncasecmp(haystack, needle, needle_len) == 0) return const_cast<char *>(haystack);

		haystack++;
		hay_len--;
	}

	return NULL;
}
#endif /* DEFINE_STRCASESTR */

/**
 * Skip some of the 'garbage' in the string that we don't want to use
 * to sort on. This way the alphabetical sorting will work better as
 * we would be actually using those characters instead of some other
 * characters such as spaces and tildes at the begin of the name.
 * @param str The string to skip the initial garbage of.
 * @return The string with the garbage skipped.
 */
static const char *SkipGarbage(const char *str)
{
	while (*str != '\0' && (*str < 'A' || IsInsideMM(*str, '[', '`' + 1) || IsInsideMM(*str, '{', '~' + 1))) str++;
	return str;
}

/**
 * Compares two strings using case insensitive natural sort.
 *
 * @param s1 First string to compare.
 * @param s2 Second string to compare.
 * @param ignore_garbage_at_front Skip punctuation characters in the front
 * @return Less than zero if s1 < s2, zero if s1 == s2, greater than zero if s1 > s2.
 */
int strnatcmp(const char *s1, const char *s2, bool ignore_garbage_at_front)
{
	if (ignore_garbage_at_front) {
		s1 = SkipGarbage(s1);
		s2 = SkipGarbage(s2);
	}
#ifdef WITH_ICU
	if (_current_collator != NULL) {
		UErrorCode status = U_ZERO_ERROR;
		int result;

		/* We want to use the new faster method for ICU 4.2 and higher. */
#if U_ICU_VERSION_MAJOR_NUM > 4 || (U_ICU_VERSION_MAJOR_NUM == 4 && U_ICU_VERSION_MINOR_NUM >= 2)
		/* The StringPiece parameter gets implicitly constructed from the char *. */
		result = _current_collator->compareUTF8(s1, s2, status);
#else /* The following for 4.0 and lower. */
		UChar buffer1[DRAW_STRING_BUFFER];
		u_strFromUTF8Lenient(buffer1, lengthof(buffer1), NULL, s1, -1, &status);
		UChar buffer2[DRAW_STRING_BUFFER];
		u_strFromUTF8Lenient(buffer2, lengthof(buffer2), NULL, s2, -1, &status);

		result = _current_collator->compare(buffer1, buffer2, status);
#endif /* ICU version check. */
		if (U_SUCCESS(status)) return result;
	}

#endif /* WITH_ICU */

	/* Do a normal comparison if ICU is missing or if we cannot create a collator. */
	return strcasecmp(s1, s2);
}