1#include "cache.h"
2#include <linux/kernel.h>
3
4int prefixcmp(const char *str, const char *prefix)
5{
6	for (; ; str++, prefix++)
7		if (!*prefix)
8			return 0;
9		else if (*str != *prefix)
10			return (unsigned char)*prefix - (unsigned char)*str;
11}
12
13/*
14 * Used as the default ->buf value, so that people can always assume
15 * buf is non NULL and ->buf is NUL terminated even for a freshly
16 * initialized strbuf.
17 */
18char strbuf_slopbuf[1];
19
20void strbuf_init(struct strbuf *sb, ssize_t hint)
21{
22	sb->alloc = sb->len = 0;
23	sb->buf = strbuf_slopbuf;
24	if (hint)
25		strbuf_grow(sb, hint);
26}
27
28void strbuf_release(struct strbuf *sb)
29{
30	if (sb->alloc) {
31		free(sb->buf);
32		strbuf_init(sb, 0);
33	}
34}
35
36char *strbuf_detach(struct strbuf *sb, size_t *sz)
37{
38	char *res = sb->alloc ? sb->buf : NULL;
39	if (sz)
40		*sz = sb->len;
41	strbuf_init(sb, 0);
42	return res;
43}
44
45void strbuf_grow(struct strbuf *sb, size_t extra)
46{
47	if (sb->len + extra + 1 <= sb->len)
48		die("you want to use way too much memory");
49	if (!sb->alloc)
50		sb->buf = NULL;
51	ALLOC_GROW(sb->buf, sb->len + extra + 1, sb->alloc);
52}
53
54static void strbuf_splice(struct strbuf *sb, size_t pos, size_t len,
55				   const void *data, size_t dlen)
56{
57	if (pos + len < pos)
58		die("you want to use way too much memory");
59	if (pos > sb->len)
60		die("`pos' is too far after the end of the buffer");
61	if (pos + len > sb->len)
62		die("`pos + len' is too far after the end of the buffer");
63
64	if (dlen >= len)
65		strbuf_grow(sb, dlen - len);
66	memmove(sb->buf + pos + dlen,
67			sb->buf + pos + len,
68			sb->len - pos - len);
69	memcpy(sb->buf + pos, data, dlen);
70	strbuf_setlen(sb, sb->len + dlen - len);
71}
72
73void strbuf_remove(struct strbuf *sb, size_t pos, size_t len)
74{
75	strbuf_splice(sb, pos, len, NULL, 0);
76}
77
78void strbuf_add(struct strbuf *sb, const void *data, size_t len)
79{
80	strbuf_grow(sb, len);
81	memcpy(sb->buf + sb->len, data, len);
82	strbuf_setlen(sb, sb->len + len);
83}
84
85void strbuf_addf(struct strbuf *sb, const char *fmt, ...)
86{
87	int len;
88	va_list ap;
89
90	if (!strbuf_avail(sb))
91		strbuf_grow(sb, 64);
92	va_start(ap, fmt);
93	len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap);
94	va_end(ap);
95	if (len < 0)
96		die("your vsnprintf is broken");
97	if (len > strbuf_avail(sb)) {
98		strbuf_grow(sb, len);
99		va_start(ap, fmt);
100		len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap);
101		va_end(ap);
102		if (len > strbuf_avail(sb)) {
103			die("this should not happen, your vsnprintf is broken");
104		}
105	}
106	strbuf_setlen(sb, sb->len + len);
107}
108
109ssize_t strbuf_read(struct strbuf *sb, int fd, ssize_t hint)
110{
111	size_t oldlen = sb->len;
112	size_t oldalloc = sb->alloc;
113
114	strbuf_grow(sb, hint ? hint : 8192);
115	for (;;) {
116		ssize_t cnt;
117
118		cnt = read(fd, sb->buf + sb->len, sb->alloc - sb->len - 1);
119		if (cnt < 0) {
120			if (oldalloc == 0)
121				strbuf_release(sb);
122			else
123				strbuf_setlen(sb, oldlen);
124			return -1;
125		}
126		if (!cnt)
127			break;
128		sb->len += cnt;
129		strbuf_grow(sb, 8192);
130	}
131
132	sb->buf[sb->len] = '\0';
133	return sb->len - oldlen;
134}
135