aboutsummaryrefslogtreecommitdiff
path: root/strbuf.c
blob: b839be491b74a034cf848d2dd043aba7d75b7b92 (plain)
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
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
#include "cache.h"
#include "refs.h"
#include "utf8.h"

int starts_with(const char *str, const char *prefix)
{
	for (; ; str++, prefix++)
		if (!*prefix)
			return 1;
		else if (*str != *prefix)
			return 0;
}

/*
 * Used as the default ->buf value, so that people can always assume
 * buf is non NULL and ->buf is NUL terminated even for a freshly
 * initialized strbuf.
 */
char strbuf_slopbuf[1];

void strbuf_init(struct strbuf *sb, size_t hint)
{
	sb->alloc = sb->len = 0;
	sb->buf = strbuf_slopbuf;
	if (hint)
		strbuf_grow(sb, hint);
}

void strbuf_release(struct strbuf *sb)
{
	if (sb->alloc) {
		free(sb->buf);
		strbuf_init(sb, 0);
	}
}

char *strbuf_detach(struct strbuf *sb, size_t *sz)
{
	char *res;
	strbuf_grow(sb, 0);
	res = sb->buf;
	if (sz)
		*sz = sb->len;
	strbuf_init(sb, 0);
	return res;
}

void strbuf_attach(struct strbuf *sb, void *buf, size_t len, size_t alloc)
{
	strbuf_release(sb);
	sb->buf   = buf;
	sb->len   = len;
	sb->alloc = alloc;
	strbuf_grow(sb, 0);
	sb->buf[sb->len] = '\0';
}

void strbuf_grow(struct strbuf *sb, size_t extra)
{
	int new_buf = !sb->alloc;
	if (unsigned_add_overflows(extra, 1) ||
	    unsigned_add_overflows(sb->len, extra + 1))
		die("you want to use way too much memory");
	if (new_buf)
		sb->buf = NULL;
	ALLOC_GROW(sb->buf, sb->len + extra + 1, sb->alloc);
	if (new_buf)
		sb->buf[0] = '\0';
}

void strbuf_trim(struct strbuf *sb)
{
	strbuf_rtrim(sb);
	strbuf_ltrim(sb);
}
void strbuf_rtrim(struct strbuf *sb)
{
	while (sb->len > 0 && isspace((unsigned char)sb->buf[sb->len - 1]))
		sb->len--;
	sb->buf[sb->len] = '\0';
}

void strbuf_ltrim(struct strbuf *sb)
{
	char *b = sb->buf;
	while (sb->len > 0 && isspace(*b)) {
		b++;
		sb->len--;
	}
	memmove(sb->buf, b, sb->len);
	sb->buf[sb->len] = '\0';
}

int strbuf_reencode(struct strbuf *sb, const char *from, const char *to)
{
	char *out;
	int len;

	if (same_encoding(from, to))
		return 0;

	out = reencode_string_len(sb->buf, sb->len, to, from, &len);
	if (!out)
		return -1;

	strbuf_attach(sb, out, len, len);
	return 0;
}

void strbuf_tolower(struct strbuf *sb)
{
	char *p = sb->buf, *end = sb->buf + sb->len;
	for (; p < end; p++)
		*p = tolower(*p);
}

struct strbuf **strbuf_split_buf(const char *str, size_t slen,
				 int terminator, int max)
{
	struct strbuf **ret = NULL;
	size_t nr = 0, alloc = 0;
	struct strbuf *t;

	while (slen) {
		int len = slen;
		if (max <= 0 || nr + 1 < max) {
			const char *end = memchr(str, terminator, slen);
			if (end)
				len = end - str + 1;
		}
		t = xmalloc(sizeof(struct strbuf));
		strbuf_init(t, len);
		strbuf_add(t, str, len);
		ALLOC_GROW(ret, nr + 2, alloc);
		ret[nr++] = t;
		str += len;
		slen -= len;
	}
	ALLOC_GROW(ret, nr + 1, alloc); /* In case string was empty */
	ret[nr] = NULL;
	return ret;
}

void strbuf_list_free(struct strbuf **sbs)
{
	struct strbuf **s = sbs;

	while (*s) {
		strbuf_release(*s);
		free(*s++);
	}
	free(sbs);
}

int strbuf_cmp(const struct strbuf *a, const struct strbuf *b)
{
	int len = a->len < b->len ? a->len: b->len;
	int cmp = memcmp(a->buf, b->buf, len);
	if (cmp)
		return cmp;
	return a->len < b->len ? -1: a->len != b->len;
}

void strbuf_splice(struct strbuf *sb, size_t pos, size_t len,
				   const void *data, size_t dlen)
{
	if (unsigned_add_overflows(pos, len))
		die("you want to use way too much memory");
	if (pos > sb->len)
		die("`pos' is too far after the end of the buffer");
	if (pos + len > sb->len)
		die("`pos + len' is too far after the end of the buffer");

	if (dlen >= len)
		strbuf_grow(sb, dlen - len);
	memmove(sb->buf + pos + dlen,
			sb->buf + pos + len,
			sb->len - pos - len);
	memcpy(sb->buf + pos, data, dlen);
	strbuf_setlen(sb, sb->len + dlen - len);
}

void strbuf_insert(struct strbuf *sb, size_t pos, const void *data, size_t len)
{
	strbuf_splice(sb, pos, 0, data, len);
}

void strbuf_remove(struct strbuf *sb, size_t pos, size_t len)
{
	strbuf_splice(sb, pos, len, "", 0);
}

void strbuf_add(struct strbuf *sb, const void *data, size_t len)
{
	strbuf_grow(sb, len);
	memcpy(sb->buf + sb->len, data, len);
	strbuf_setlen(sb, sb->len + len);
}

void strbuf_addbuf(struct strbuf *sb, const struct strbuf *sb2)
{
	strbuf_grow(sb, sb2->len);
	memcpy(sb->buf + sb->len, sb2->buf, sb2->len);
	strbuf_setlen(sb, sb->len + sb2->len);
}

void strbuf_adddup(struct strbuf *sb, size_t pos, size_t len)
{
	strbuf_grow(sb, len);
	memcpy(sb->buf + sb->len, sb->buf + pos, len);
	strbuf_setlen(sb, sb->len + len);
}

void strbuf_addchars(struct strbuf *sb, int c, size_t n)
{
	strbuf_grow(sb, n);
	memset(sb->buf + sb->len, c, n);
	strbuf_setlen(sb, sb->len + n);
}

void strbuf_addf(struct strbuf *sb, const char *fmt, ...)
{
	va_list ap;
	va_start(ap, fmt);
	strbuf_vaddf(sb, fmt, ap);
	va_end(ap);
}

static void add_lines(struct strbuf *out,
			const char *prefix1,
			const char *prefix2,
			const char *buf, size_t size)
{
	while (size) {
		const char *prefix;
		const char *next = memchr(buf, '\n', size);
		next = next ? (next + 1) : (buf + size);

		prefix = ((prefix2 && (buf[0] == '\n' || buf[0] == '\t'))
			  ? prefix2 : prefix1);
		strbuf_addstr(out, prefix);
		strbuf_add(out, buf, next - buf);
		size -= next - buf;
		buf = next;
	}
	strbuf_complete_line(out);
}

void strbuf_add_commented_lines(struct strbuf *out, const char *buf, size_t size)
{
	static char prefix1[3];
	static char prefix2[2];

	if (prefix1[0] != comment_line_char) {
		xsnprintf(prefix1, sizeof(prefix1), "%c ", comment_line_char);
		xsnprintf(prefix2, sizeof(prefix2), "%c", comment_line_char);
	}
	add_lines(out, prefix1, prefix2, buf, size);
}

void strbuf_commented_addf(struct strbuf *sb, const char *fmt, ...)
{
	va_list params;
	struct strbuf buf = STRBUF_INIT;
	int incomplete_line = sb->len && sb->buf[sb->len - 1] != '\n';

	va_start(params, fmt);
	strbuf_vaddf(&buf, fmt, params);
	va_end(params);

	strbuf_add_commented_lines(sb, buf.buf, buf.len);
	if (incomplete_line)
		sb->buf[--sb->len] = '\0';

	strbuf_release(&buf);
}

void strbuf_vaddf(struct strbuf *sb, const char *fmt, va_list ap)
{
	int len;
	va_list cp;

	if (!strbuf_avail(sb))
		strbuf_grow(sb, 64);
	va_copy(cp, ap);
	len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, cp);
	va_end(cp);
	if (len < 0)
		die("BUG: your vsnprintf is broken (returned %d)", len);
	if (len > strbuf_avail(sb)) {
		strbuf_grow(sb, len);
		len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap);
		if (len > strbuf_avail(sb))
			die("BUG: your vsnprintf is broken (insatiable)");
	}
	strbuf_setlen(sb, sb->len + len);
}

void strbuf_expand(struct strbuf *sb, const char *format, expand_fn_t fn,
		   void *context)
{
	for (;;) {
		const char *percent;
		size_t consumed;

		percent = strchrnul(format, '%');
		strbuf_add(sb, format, percent - format);
		if (!*percent)
			break;
		format = percent + 1;

		if (*format == '%') {
			strbuf_addch(sb, '%');
			format++;
			continue;
		}

		consumed = fn(sb, format, context);
		if (consumed)
			format += consumed;
		else
			strbuf_addch(sb, '%');
	}
}

size_t strbuf_expand_dict_cb(struct strbuf *sb, const char *placeholder,
		void *context)
{
	struct strbuf_expand_dict_entry *e = context;
	size_t len;

	for (; e->placeholder && (len = strlen(e->placeholder)); e++) {
		if (!strncmp(placeholder, e->placeholder, len)) {
			if (e->value)
				strbuf_addstr(sb, e->value);
			return len;
		}
	}
	return 0;
}

void strbuf_addbuf_percentquote(struct strbuf *dst, const struct strbuf *src)
{
	int i, len = src->len;

	for (i = 0; i < len; i++) {
		if (src->buf[i] == '%')
			strbuf_addch(dst, '%');
		strbuf_addch(dst, src->buf[i]);
	}
}

size_t strbuf_fread(struct strbuf *sb, size_t size, FILE *f)
{
	size_t res;
	size_t oldalloc = sb->alloc;

	strbuf_grow(sb, size);
	res = fread(sb->buf + sb->len, 1, size, f);
	if (res > 0)
		strbuf_setlen(sb, sb->len + res);
	else if (oldalloc == 0)
		strbuf_release(sb);
	return res;
}

ssize_t strbuf_read(struct strbuf *sb, int fd, size_t hint)
{
	size_t oldlen = sb->len;
	size_t oldalloc = sb->alloc;

	strbuf_grow(sb, hint ? hint : 8192);
	for (;;) {
		ssize_t want = sb->alloc - sb->len - 1;
		ssize_t got = read_in_full(fd, sb->buf + sb->len, want);

		if (got < 0) {
			if (oldalloc == 0)
				strbuf_release(sb);
			else
				strbuf_setlen(sb, oldlen);
			return -1;
		}
		sb->len += got;
		if (got < want)
			break;
		strbuf_grow(sb, 8192);
	}

	sb->buf[sb->len] = '\0';
	return sb->len - oldlen;
}

ssize_t strbuf_read_once(struct strbuf *sb, int fd, size_t hint)
{
	ssize_t cnt;

	strbuf_grow(sb, hint ? hint : 8192);
	cnt = xread(fd, sb->buf + sb->len, sb->alloc - sb->len - 1);
	if (cnt > 0)
		strbuf_setlen(sb, sb->len + cnt);
	return cnt;
}

ssize_t strbuf_write(struct strbuf *sb, FILE *f)
{
	return sb->len ? fwrite(sb->buf, 1, sb->len, f) : 0;
}


#define STRBUF_MAXLINK (2*PATH_MAX)

int strbuf_readlink(struct strbuf *sb, const char *path, size_t hint)
{
	size_t oldalloc = sb->alloc;

	if (hint < 32)
		hint = 32;

	while (hint < STRBUF_MAXLINK) {
		int len;

		strbuf_grow(sb, hint);
		len = readlink(path, sb->buf, hint);
		if (len < 0) {
			if (errno != ERANGE)
				break;
		} else if (len < hint) {
			strbuf_setlen(sb, len);
			return 0;
		}

		/* .. the buffer was too small - try again */
		hint *= 2;
	}
	if (oldalloc == 0)
		strbuf_release(sb);
	return -1;
}

int strbuf_getcwd(struct strbuf *sb)
{
	size_t oldalloc = sb->alloc;
	size_t guessed_len = 128;

	for (;; guessed_len *= 2) {
		strbuf_grow(sb, guessed_len);
		if (getcwd(sb->buf, sb->alloc)) {
			strbuf_setlen(sb, strlen(sb->buf));
			return 0;
		}
		if (errno != ERANGE)
			break;
	}
	if (oldalloc == 0)
		strbuf_release(sb);
	else
		strbuf_reset(sb);
	return -1;
}

#ifdef HAVE_GETDELIM
int strbuf_getwholeline(struct strbuf *sb, FILE *fp, int term)
{
	ssize_t r;

	if (feof(fp))
		return EOF;

	strbuf_reset(sb);

	/* Translate slopbuf to NULL, as we cannot call realloc on it */
	if (!sb->alloc)
		sb->buf = NULL;
	r = getdelim(&sb->buf, &sb->alloc, term, fp);

	if (r > 0) {
		sb->len = r;
		return 0;
	}
	assert(r == -1);

	/*
	 * Normally we would have called xrealloc, which will try to free
	 * memory and recover. But we have no way to tell getdelim() to do so.
	 * Worse, we cannot try to recover ENOMEM ourselves, because we have
	 * no idea how many bytes were read by getdelim.
	 *
	 * Dying here is reasonable. It mirrors what xrealloc would do on
	 * catastrophic memory failure. We skip the opportunity to free pack
	 * memory and retry, but that's unlikely to help for a malloc small
	 * enough to hold a single line of input, anyway.
	 */
	if (errno == ENOMEM)
		die("Out of memory, getdelim failed");

	/*
	 * Restore strbuf invariants; if getdelim left us with a NULL pointer,
	 * we can just re-init, but otherwise we should make sure that our
	 * length is empty, and that the result is NUL-terminated.
	 */
	if (!sb->buf)
		strbuf_init(sb, 0);
	else
		strbuf_reset(sb);
	return EOF;
}
#else
int strbuf_getwholeline(struct strbuf *sb, FILE *fp, int term)
{
	int ch;

	if (feof(fp))
		return EOF;

	strbuf_reset(sb);
	flockfile(fp);
	while ((ch = getc_unlocked(fp)) != EOF) {
		if (!strbuf_avail(sb))
			strbuf_grow(sb, 1);
		sb->buf[sb->len++] = ch;
		if (ch == term)
			break;
	}
	funlockfile(fp);
	if (ch == EOF && sb->len == 0)
		return EOF;

	sb->buf[sb->len] = '\0';
	return 0;
}
#endif

static int strbuf_getdelim(struct strbuf *sb, FILE *fp, int term)
{
	if (strbuf_getwholeline(sb, fp, term))
		return EOF;
	if (sb->buf[sb->len - 1] == term)
		strbuf_setlen(sb, sb->len - 1);
	return 0;
}

int strbuf_getline(struct strbuf *sb, FILE *fp)
{
	if (strbuf_getwholeline(sb, fp, '\n'))
		return EOF;
	if (sb->buf[sb->len - 1] == '\n') {
		strbuf_setlen(sb, sb->len - 1);
		if (sb->len && sb->buf[sb->len - 1] == '\r')
			strbuf_setlen(sb, sb->len - 1);
	}
	return 0;
}

int strbuf_getline_lf(struct strbuf *sb, FILE *fp)
{
	return strbuf_getdelim(sb, fp, '\n');
}

int strbuf_getline_nul(struct strbuf *sb, FILE *fp)
{
	return strbuf_getdelim(sb, fp, '\0');
}

int strbuf_getwholeline_fd(struct strbuf *sb, int fd, int term)
{
	strbuf_reset(sb);

	while (1) {
		char ch;
		ssize_t len = xread(fd, &ch, 1);
		if (len <= 0)
			return EOF;
		strbuf_addch(sb, ch);
		if (ch == term)
			break;
	}
	return 0;
}

ssize_t strbuf_read_file(struct strbuf *sb, const char *path, size_t hint)
{
	int fd;
	ssize_t len;

	fd = open(path, O_RDONLY);
	if (fd < 0)
		return -1;
	len = strbuf_read(sb, fd, hint);
	close(fd);
	if (len < 0)
		return -1;

	return len;
}

void strbuf_add_lines(struct strbuf *out, const char *prefix,
		      const char *buf, size_t size)
{
	add_lines(out, prefix, NULL, buf, size);
}

void strbuf_addstr_xml_quoted(struct strbuf *buf, const char *s)
{
	while (*s) {
		size_t len = strcspn(s, "\"<>&");
		strbuf_add(buf, s, len);
		s += len;
		switch (*s) {
		case '"':
			strbuf_addstr(buf, "&quot;");
			break;
		case '<':
			strbuf_addstr(buf, "&lt;");
			break;
		case '>':
			strbuf_addstr(buf, "&gt;");
			break;
		case '&':
			strbuf_addstr(buf, "&amp;");
			break;
		case 0:
			return;
		}
		s++;
	}
}

static int is_rfc3986_reserved(char ch)
{
	switch (ch) {
		case '!': case '*': case '\'': case '(': case ')': case ';':
		case ':': case '@': case '&': case '=': case '+': case '$':
		case ',': case '/': case '?': case '#': case '[': case ']':
			return 1;
	}
	return 0;
}

static int is_rfc3986_unreserved(char ch)
{
	return isalnum(ch) ||
		ch == '-' || ch == '_' || ch == '.' || ch == '~';
}

static void strbuf_add_urlencode(struct strbuf *sb, const char *s, size_t len,
				 int reserved)
{
	strbuf_grow(sb, len);
	while (len--) {
		char ch = *s++;
		if (is_rfc3986_unreserved(ch) ||
		    (!reserved && is_rfc3986_reserved(ch)))
			strbuf_addch(sb, ch);
		else
			strbuf_addf(sb, "%%%02x", ch);
	}
}

void strbuf_addstr_urlencode(struct strbuf *sb, const char *s,
			     int reserved)
{
	strbuf_add_urlencode(sb, s, strlen(s), reserved);
}

void strbuf_humanise_bytes(struct strbuf *buf, off_t bytes)
{
	if (bytes > 1 << 30) {
		strbuf_addf(buf, "%u.%2.2u GiB",
			    (int)(bytes >> 30),
			    (int)(bytes & ((1 << 30) - 1)) / 10737419);
	} else if (bytes > 1 << 20) {
		int x = bytes + 5243;  /* for rounding */
		strbuf_addf(buf, "%u.%2.2u MiB",
			    x >> 20, ((x & ((1 << 20) - 1)) * 100) >> 20);
	} else if (bytes > 1 << 10) {
		int x = bytes + 5;  /* for rounding */
		strbuf_addf(buf, "%u.%2.2u KiB",
			    x >> 10, ((x & ((1 << 10) - 1)) * 100) >> 10);
	} else {
		strbuf_addf(buf, "%u bytes", (int)bytes);
	}
}

void strbuf_add_absolute_path(struct strbuf *sb, const char *path)
{
	if (!*path)
		die("The empty string is not a valid path");
	if (!is_absolute_path(path)) {
		struct stat cwd_stat, pwd_stat;
		size_t orig_len = sb->len;
		char *cwd = xgetcwd();
		char *pwd = getenv("PWD");
		if (pwd && strcmp(pwd, cwd) &&
		    !stat(cwd, &cwd_stat) &&
		    (cwd_stat.st_dev || cwd_stat.st_ino) &&
		    !stat(pwd, &pwd_stat) &&
		    pwd_stat.st_dev == cwd_stat.st_dev &&
		    pwd_stat.st_ino == cwd_stat.st_ino)
			strbuf_addstr(sb, pwd);
		else
			strbuf_addstr(sb, cwd);
		if (sb->len > orig_len && !is_dir_sep(sb->buf[sb->len - 1]))
			strbuf_addch(sb, '/');
		free(cwd);
	}
	strbuf_addstr(sb, path);
}

int printf_ln(const char *fmt, ...)
{
	int ret;
	va_list ap;
	va_start(ap, fmt);
	ret = vprintf(fmt, ap);
	va_end(ap);
	if (ret < 0 || putchar('\n') == EOF)
		return -1;
	return ret + 1;
}

int fprintf_ln(FILE *fp, const char *fmt, ...)
{
	int ret;
	va_list ap;
	va_start(ap, fmt);
	ret = vfprintf(fp, fmt, ap);
	va_end(ap);
	if (ret < 0 || putc('\n', fp) == EOF)
		return -1;
	return ret + 1;
}

char *xstrdup_tolower(const char *string)
{
	char *result;
	size_t len, i;

	len = strlen(string);
	result = xmallocz(len);
	for (i = 0; i < len; i++)
		result[i] = tolower(string[i]);
	result[i] = '\0';
	return result;
}

char *xstrvfmt(const char *fmt, va_list ap)
{
	struct strbuf buf = STRBUF_INIT;
	strbuf_vaddf(&buf, fmt, ap);
	return strbuf_detach(&buf, NULL);
}

char *xstrfmt(const char *fmt, ...)
{
	va_list ap;
	char *ret;

	va_start(ap, fmt);
	ret = xstrvfmt(fmt, ap);
	va_end(ap);

	return ret;
}

void strbuf_addftime(struct strbuf *sb, const char *fmt, const struct tm *tm)
{
	size_t hint = 128;
	size_t len;

	if (!*fmt)
		return;

	strbuf_grow(sb, hint);
	len = strftime(sb->buf + sb->len, sb->alloc - sb->len, fmt, tm);

	if (!len) {
		/*
		 * strftime reports "0" if it could not fit the result in the buffer.
		 * Unfortunately, it also reports "0" if the requested time string
		 * takes 0 bytes. So our strategy is to munge the format so that the
		 * output contains at least one character, and then drop the extra
		 * character before returning.
		 */
		struct strbuf munged_fmt = STRBUF_INIT;
		strbuf_addf(&munged_fmt, "%s ", fmt);
		while (!len) {
			hint *= 2;
			strbuf_grow(sb, hint);
			len = strftime(sb->buf + sb->len, sb->alloc - sb->len,
				       munged_fmt.buf, tm);
		}
		strbuf_release(&munged_fmt);
		len--; /* drop munged space */
	}
	strbuf_setlen(sb, sb->len + len);
}

void strbuf_add_unique_abbrev(struct strbuf *sb, const unsigned char *sha1,
			      int abbrev_len)
{
	int r;
	strbuf_grow(sb, GIT_SHA1_HEXSZ + 1);
	r = find_unique_abbrev_r(sb->buf + sb->len, sha1, abbrev_len);
	strbuf_setlen(sb, sb->len + r);
}

/*
 * Returns the length of a line, without trailing spaces.
 *
 * If the line ends with newline, it will be removed too.
 */
static size_t cleanup(char *line, size_t len)
{
	while (len) {
		unsigned char c = line[len - 1];
		if (!isspace(c))
			break;
		len--;
	}

	return len;
}

/*
 * Remove empty lines from the beginning and end
 * and also trailing spaces from every line.
 *
 * Turn multiple consecutive empty lines between paragraphs
 * into just one empty line.
 *
 * If the input has only empty lines and spaces,
 * no output will be produced.
 *
 * If last line does not have a newline at the end, one is added.
 *
 * Enable skip_comments to skip every line starting with comment
 * character.
 */
void strbuf_stripspace(struct strbuf *sb, int skip_comments)
{
	int empties = 0;
	size_t i, j, len, newlen;
	char *eol;

	/* We may have to add a newline. */
	strbuf_grow(sb, 1);

	for (i = j = 0; i < sb->len; i += len, j += newlen) {
		eol = memchr(sb->buf + i, '\n', sb->len - i);
		len = eol ? eol - (sb->buf + i) + 1 : sb->len - i;

		if (skip_comments && len && sb->buf[i] == comment_line_char) {
			newlen = 0;
			continue;
		}
		newlen = cleanup(sb->buf + i, len);

		/* Not just an empty line? */
		if (newlen) {
			if (empties > 0 && j > 0)
				sb->buf[j++] = '\n';
			empties = 0;
			memmove(sb->buf + j, sb->buf + i, newlen);
			sb->buf[newlen + j++] = '\n';
		} else {
			empties++;
		}
	}

	strbuf_setlen(sb, j);
}