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John Kacur8b40f522009-09-24 18:02:18 +02001#ifndef __PERF_STRBUF_H
2#define __PERF_STRBUF_H
Ingo Molnar07800602009-04-20 15:00:56 +02003
4/*
5 * Strbuf's can be use in many ways: as a byte array, or to store arbitrary
6 * long, overflow safe strings.
7 *
8 * Strbufs has some invariants that are very important to keep in mind:
9 *
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.
12 *
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.
16 *
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.
21 *
22 * Note that it is OK to "play" with the buffer directly if you work it
23 * that way:
24 *
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);
30 *
31 * Of course, SOME_OTHER_SIZE must be smaller or equal to strbuf_avail(sb).
32 *
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.
35 *
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.
39 */
40
41#include <assert.h>
42
43extern char strbuf_slopbuf[];
44struct strbuf {
45 size_t alloc;
46 size_t len;
47 char *buf;
48};
49
50#define STRBUF_INIT { 0, 0, strbuf_slopbuf }
51
52/*----- strbuf life cycle -----*/
Ingo Molnarf37a2912009-07-01 12:37:06 +020053extern void strbuf_init(struct strbuf *buf, ssize_t hint);
Ingo Molnar07800602009-04-20 15:00:56 +020054extern void strbuf_release(struct strbuf *);
55extern char *strbuf_detach(struct strbuf *, size_t *);
Ingo Molnar07800602009-04-20 15:00:56 +020056
57/*----- strbuf size related -----*/
Ingo Molnarf37a2912009-07-01 12:37:06 +020058static inline ssize_t strbuf_avail(const struct strbuf *sb) {
Ingo Molnar07800602009-04-20 15:00:56 +020059 return sb->alloc ? sb->alloc - sb->len - 1 : 0;
60}
61
62extern void strbuf_grow(struct strbuf *, size_t);
63
64static inline void strbuf_setlen(struct strbuf *sb, size_t len) {
65 if (!sb->alloc)
66 strbuf_grow(sb, 0);
67 assert(len < sb->alloc);
68 sb->len = len;
69 sb->buf[len] = '\0';
70}
Ingo Molnar07800602009-04-20 15:00:56 +020071
72/*----- add data in your buffer -----*/
73static inline void strbuf_addch(struct strbuf *sb, int c) {
74 strbuf_grow(sb, 1);
75 sb->buf[sb->len++] = c;
76 sb->buf[sb->len] = '\0';
77}
78
Ingo Molnar07800602009-04-20 15:00:56 +020079extern void strbuf_remove(struct strbuf *, size_t pos, size_t len);
80
Ingo Molnar07800602009-04-20 15:00:56 +020081extern void strbuf_add(struct strbuf *, const void *, size_t);
82static inline void strbuf_addstr(struct strbuf *sb, const char *s) {
83 strbuf_add(sb, s, strlen(s));
84}
Ingo Molnar07800602009-04-20 15:00:56 +020085
86__attribute__((format(printf,2,3)))
87extern void strbuf_addf(struct strbuf *sb, const char *fmt, ...);
88
Ingo Molnar07800602009-04-20 15:00:56 +020089/* XXX: if read fails, any partial read is undone */
Ingo Molnarf37a2912009-07-01 12:37:06 +020090extern ssize_t strbuf_read(struct strbuf *, int fd, ssize_t hint);
Ingo Molnar07800602009-04-20 15:00:56 +020091
John Kacur8b40f522009-09-24 18:02:18 +020092#endif /* __PERF_STRBUF_H */