1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
|
#ifndef _SCBUF_C_
#define _SCBUF_C_
/* -*- linux-c -*- */
/** @file scbuf.c
* @addtogroup scbuf Scratch Buffer
* Scratch Buffer Functions.
* The scratch buffer is for collecting output before storing in a map,
* printing, etc. This is a per-cpu static buffer. It is necessary because
* of the limited stack space available in the kernel.
* @{
*/
/** Maximum size of buffer, not including terminating NULL */
#define STP_BUF_LEN 8191
/** Scratch buffer for printing, building strings, etc */
char _stp_scbuf[STP_BUF_LEN+1];
static int _stp_scbuf_len = STP_BUF_LEN;
/** Sprint into the scratch buffer.
* Like printf, except output goes into #_stp_scbuf,
* which will contain the null-terminated output.
* Safe because overflowing #_stp_scbuf is not allowed.
* Size is limited by length of scratch buffer, STP_BUF_LEN.
*
* @param fmt A printf-style format string followed by a
* variable number of args.
* @sa _stp_scbuf_clear
*/
void _stp_sprint (const char *fmt, ...)
{
int num;
va_list args;
char *buf = _stp_scbuf + STP_BUF_LEN - _stp_scbuf_len;
va_start(args, fmt);
num = vscnprintf(buf, _stp_scbuf_len, fmt, args);
va_end(args);
if (num > 0)
_stp_scbuf_len -= num;
}
void _stp_sprint_str (const char *str)
{
char *buf = _stp_scbuf + STP_BUF_LEN - _stp_scbuf_len;
int num = strlen (str);
if (num > _stp_scbuf_len)
num = _stp_scbuf_len;
strncpy (buf, str, num);
_stp_scbuf_len -= num;
}
/** Clear the scratch buffer.
* Output from _stp_sprint() will accumulate in the buffer
* until this is called.
*/
void _stp_scbuf_clear (void)
{
_stp_scbuf_len = STP_BUF_LEN;
_stp_scbuf[0] = 0;
}
static char *_stp_scbuf_cur (void)
{
return _stp_scbuf + STP_BUF_LEN - _stp_scbuf_len;
}
/** @} */
#endif /* _SCBUF_C_ */
|
