1 // SPDX-License-Identifier: GPL-2.0
4 #include <linux/kernel.h>
8 * Used as the default ->buf value, so that people can always assume
9 * buf is non NULL and ->buf is NUL terminated even for a freshly
12 char strbuf_slopbuf[1];
14 int strbuf_init(struct strbuf *sb, ssize_t hint)
16 sb->alloc = sb->len = 0;
17 sb->buf = strbuf_slopbuf;
19 return strbuf_grow(sb, hint);
23 void strbuf_release(struct strbuf *sb)
31 char *strbuf_detach(struct strbuf *sb, size_t *sz)
33 char *res = sb->alloc ? sb->buf : NULL;
40 int strbuf_grow(struct strbuf *sb, size_t extra)
43 size_t nr = sb->len + extra + 1;
51 if (alloc_nr(sb->alloc) > nr)
52 nr = alloc_nr(sb->alloc);
55 * Note that sb->buf == strbuf_slopbuf if sb->alloc == 0, and it is
56 * a static variable. Thus we have to avoid passing it to realloc.
58 buf = realloc(sb->alloc ? sb->buf : NULL, nr * sizeof(*buf));
67 int strbuf_addch(struct strbuf *sb, int c)
69 int ret = strbuf_grow(sb, 1);
73 sb->buf[sb->len++] = c;
74 sb->buf[sb->len] = '\0';
78 int strbuf_add(struct strbuf *sb, const void *data, size_t len)
80 int ret = strbuf_grow(sb, len);
84 memcpy(sb->buf + sb->len, data, len);
85 return strbuf_setlen(sb, sb->len + len);
88 static int strbuf_addv(struct strbuf *sb, const char *fmt, va_list ap)
93 if (!strbuf_avail(sb)) {
94 ret = strbuf_grow(sb, 64);
99 va_copy(ap_saved, ap);
100 len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap);
103 if (len > strbuf_avail(sb)) {
104 ret = strbuf_grow(sb, len);
107 len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap_saved);
109 if (len > strbuf_avail(sb)) {
110 pr_debug("this should not happen, your vsnprintf is broken");
114 return strbuf_setlen(sb, sb->len + len);
117 int strbuf_addf(struct strbuf *sb, const char *fmt, ...)
123 ret = strbuf_addv(sb, fmt, ap);
128 ssize_t strbuf_read(struct strbuf *sb, int fd, ssize_t hint)
130 size_t oldlen = sb->len;
131 size_t oldalloc = sb->alloc;
134 ret = strbuf_grow(sb, hint ? hint : 8192);
141 cnt = read(fd, sb->buf + sb->len, sb->alloc - sb->len - 1);
146 strbuf_setlen(sb, oldlen);
152 ret = strbuf_grow(sb, 8192);
157 sb->buf[sb->len] = '\0';
158 return sb->len - oldlen;