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
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
|
#include "stdio_impl.h"
#include <limits.h>
#include <string.h>
#include <errno.h>
#include <stdint.h>
struct cookie {
char *s;
size_t n;
};
#define MIN(a, b) ((a) < (b) ? (a) : (b))
static size_t sn_write(FILE *f, const unsigned char *s, size_t l)
{
struct cookie *c = f->cookie;
size_t k = MIN(c->n, f->wpos - f->wbase);
if (k) {
memcpy(c->s, f->wbase, k);
c->s += k;
c->n -= k;
}
k = MIN(c->n, l);
if (k) {
memcpy(c->s, s, k);
c->s += k;
c->n -= k;
}
*c->s = 0;
f->wpos = f->wbase = f->buf;
/* pretend to succeed, even if we discarded extra data */
return l;
}
int vsnprintf(char *restrict s, size_t n, const char *restrict fmt, va_list ap)
{
unsigned char buf[1];
char dummy[1];
struct cookie c = { .s = n ? s : dummy, .n = n ? n-1 : 0 };
FILE f = {
.lbf = EOF,
.write = sn_write,
.lock = -1,
.buf = buf,
.cookie = &c,
};
*c.s = 0;
return vfprintf(&f, fmt, ap);
}
// XXX EMSCRIPTEN
int vsniprintf(char *restrict s, size_t n, const char *restrict fmt, va_list ap)
{
int r;
char b;
FILE f = { .lbf = EOF, .write = sn_write, .lock = -1 };
if (n-1 > INT_MAX-1) {
if (n) {
errno = EOVERFLOW;
return -1;
}
s = &b;
n = 1;
}
/* Ensure pointers don't wrap if "infinite" n is passed in */
if (n > (char *)0+SIZE_MAX-s-1) n = (char *)0+SIZE_MAX-s-1;
f.buf_size = n;
f.buf = f.wpos = (void *)s;
f.wbase = f.wend = (void *)(s+n);
r = vfiprintf(&f, fmt, ap);
/* Null-terminate, overwriting last char if dest buffer is full */
if (n) f.wpos[-(f.wpos == f.wend)] = 0;
return r;
}
int __small_vsnprintf(char *restrict s, size_t n, const char *restrict fmt, va_list ap)
{
int r;
char b;
FILE f = { .lbf = EOF, .write = sn_write, .lock = -1 };
if (n-1 > INT_MAX-1) {
if (n) {
errno = EOVERFLOW;
return -1;
}
s = &b;
n = 1;
}
/* Ensure pointers don't wrap if "infinite" n is passed in */
if (n > (char *)0+SIZE_MAX-s-1) n = (char *)0+SIZE_MAX-s-1;
f.buf_size = n;
f.buf = f.wpos = (void *)s;
f.wbase = f.wend = (void *)(s+n);
r = __small_vfprintf(&f, fmt, ap);
/* Null-terminate, overwriting last char if dest buffer is full */
if (n) f.wpos[-(f.wpos == f.wend)] = 0;
return r;
}
|
