summaryrefslogtreecommitdiffstats
path: root/tools/perf/util/strbuf.c
blob: 3d1cf5bf7f184b9c18a0fbb59768510e3620cc6f (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
// SPDX-License-Identifier: GPL-2.0
#include "debug.h"
#include "util.h"
#include <linux/kernel.h>
#include <errno.h>

/*
 * 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];

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

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

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

int strbuf_grow(struct strbuf *sb, size_t extra)
{
	char *buf;
	size_t nr = sb->len + extra + 1;

	if (nr < sb->alloc)
		return 0;

	if (nr <= sb->len)
		return -E2BIG;

	if (alloc_nr(sb->alloc) > nr)
		nr = alloc_nr(sb->alloc);

	/*
	 * Note that sb->buf == strbuf_slopbuf if sb->alloc == 0, and it is
	 * a static variable. Thus we have to avoid passing it to realloc.
	 */
	buf = realloc(sb->alloc ? sb->buf : NULL, nr * sizeof(*buf));
	if (!buf)
		return -ENOMEM;

	sb->buf = buf;
	sb->alloc = nr;
	return 0;
}

int strbuf_addch(struct strbuf *sb, int c)
{
	int ret = strbuf_grow(sb, 1);
	if (ret)
		return ret;

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

int strbuf_add(struct strbuf *sb, const void *data, size_t len)
{
	int ret = strbuf_grow(sb, len);
	if (ret)
		return ret;

	memcpy(sb->buf + sb->len, data, len);
	return strbuf_setlen(sb, sb->len + len);
}

static int strbuf_addv(struct strbuf *sb, const char *fmt, va_list ap)
{
	int len, ret;
	va_list ap_saved;

	if (!strbuf_avail(sb)) {
		ret = strbuf_grow(sb, 64);
		if (ret)
			return ret;
	}

	va_copy(ap_saved, ap);
	len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap);
	if (len < 0)
		return len;
	if (len > strbuf_avail(sb)) {
		ret = strbuf_grow(sb, len);
		if (ret)
			return ret;
		len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap_saved);
		va_end(ap_saved);
		if (len > strbuf_avail(sb)) {
			pr_debug("this should not happen, your vsnprintf is broken");
			return -EINVAL;
		}
	}
	return strbuf_setlen(sb, sb->len + len);
}

int strbuf_addf(struct strbuf *sb, const char *fmt, ...)
{
	va_list ap;
	int ret;

	va_start(ap, fmt);
	ret = strbuf_addv(sb, fmt, ap);
	va_end(ap);
	return ret;
}

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

	ret = strbuf_grow(sb, hint ? hint : 8192);
	if (ret)
		return ret;

	for (;;) {
		ssize_t cnt;

		cnt = read(fd, sb->buf + sb->len, sb->alloc - sb->len - 1);
		if (cnt < 0) {
			if (oldalloc == 0)
				strbuf_release(sb);
			else
				strbuf_setlen(sb, oldlen);
			return cnt;
		}
		if (!cnt)
			break;
		sb->len += cnt;
		ret = strbuf_grow(sb, 8192);
		if (ret)
			return ret;
	}

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