1 #ifndef __PERF_STRBUF_H
2 #define __PERF_STRBUF_H
5 * Strbuf's can be use in many ways: as a byte array, or to store arbitrary
6 * long, overflow safe strings.
8 * Strbufs has some invariants that are very important to keep in mind:
10 * 1. the ->buf member is always malloc-ed, hence strbuf's can be used to
11 * build complex strings/buffers whose final size isn't easily known.
13 * It is NOT legal to copy the ->buf pointer away.
14 * `strbuf_detach' is the operation that detachs a buffer from its shell
15 * while keeping the shell valid wrt its invariants.
17 * 2. the ->buf member is a byte array that has at least ->len + 1 bytes
18 * allocated. The extra byte is used to store a '\0', allowing the ->buf
19 * member to be a valid C-string. Every strbuf function ensure this
20 * invariant is preserved.
22 * Note that it is OK to "play" with the buffer directly if you work it
25 * strbuf_grow(sb, SOME_SIZE);
26 * ... Here, the memory array starting at sb->buf, and of length
27 * ... strbuf_avail(sb) is all yours, and you are sure that
28 * ... strbuf_avail(sb) is at least SOME_SIZE.
29 * strbuf_setlen(sb, sb->len + SOME_OTHER_SIZE);
31 * Of course, SOME_OTHER_SIZE must be smaller or equal to strbuf_avail(sb).
33 * Doing so is safe, though if it has to be done in many places, adding the
34 * missing API to the strbuf module is the way to go.
36 * XXX: do _not_ assume that the area that is yours is of size ->alloc - 1
37 * even if it's true in the current implementation. Alloc is somehow a
38 * "private" member that should not be messed with.
45 #include <sys/types.h>
47 extern char strbuf_slopbuf[];
54 #define STRBUF_INIT { 0, 0, strbuf_slopbuf }
56 /*----- strbuf life cycle -----*/
57 int strbuf_init(struct strbuf *buf, ssize_t hint);
58 void strbuf_release(struct strbuf *buf);
59 char *strbuf_detach(struct strbuf *buf, size_t *);
61 /*----- strbuf size related -----*/
62 static inline ssize_t strbuf_avail(const struct strbuf *sb) {
63 return sb->alloc ? sb->alloc - sb->len - 1 : 0;
66 int strbuf_grow(struct strbuf *buf, size_t);
68 static inline int strbuf_setlen(struct strbuf *sb, size_t len) {
70 int ret = strbuf_grow(sb, 0);
74 assert(len < sb->alloc);
80 /*----- add data in your buffer -----*/
81 int strbuf_addch(struct strbuf *sb, int c);
83 int strbuf_add(struct strbuf *buf, const void *, size_t);
84 static inline int strbuf_addstr(struct strbuf *sb, const char *s) {
85 return strbuf_add(sb, s, strlen(s));
88 __attribute__((format(printf,2,3)))
89 int strbuf_addf(struct strbuf *sb, const char *fmt, ...);
91 /* XXX: if read fails, any partial read is undone */
92 ssize_t strbuf_read(struct strbuf *, int fd, ssize_t hint);
94 #endif /* __PERF_STRBUF_H */