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8b40f521 JK |
1 | #ifndef __PERF_STRBUF_H |
2 | #define __PERF_STRBUF_H | |
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3 | |
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 | ||
43 | extern char strbuf_slopbuf[]; | |
44 | struct 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 -----*/ | |
f37a291c | 53 | extern void strbuf_init(struct strbuf *buf, ssize_t hint); |
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54 | extern void strbuf_release(struct strbuf *); |
55 | extern char *strbuf_detach(struct strbuf *, size_t *); | |
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56 | |
57 | /*----- strbuf size related -----*/ | |
f37a291c | 58 | static inline ssize_t strbuf_avail(const struct strbuf *sb) { |
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59 | return sb->alloc ? sb->alloc - sb->len - 1 : 0; |
60 | } | |
61 | ||
62 | extern void strbuf_grow(struct strbuf *, size_t); | |
63 | ||
64 | static 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 | } | |
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71 | |
72 | /*----- add data in your buffer -----*/ | |
73 | static 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 | ||
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79 | extern void strbuf_remove(struct strbuf *, size_t pos, size_t len); |
80 | ||
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81 | extern void strbuf_add(struct strbuf *, const void *, size_t); |
82 | static inline void strbuf_addstr(struct strbuf *sb, const char *s) { | |
83 | strbuf_add(sb, s, strlen(s)); | |
84 | } | |
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85 | |
86 | __attribute__((format(printf,2,3))) | |
87 | extern void strbuf_addf(struct strbuf *sb, const char *fmt, ...); | |
88 | ||
07800601 | 89 | /* XXX: if read fails, any partial read is undone */ |
f37a291c | 90 | extern ssize_t strbuf_read(struct strbuf *, int fd, ssize_t hint); |
07800601 | 91 | |
8b40f521 | 92 | #endif /* __PERF_STRBUF_H */ |