in net/ip/lwip_base/src/netif/ppp/utils.c [135:402]
int ppp_vslprintf(char *buf, int buflen, const char *fmt, va_list args) {
int c, i, n;
int width, prec, fillch;
int base, len, neg, quoted;
unsigned long val = 0;
const char *f;
char *str, *buf0;
const unsigned char *p;
char num[32];
#if 0 /* need port */
time_t t;
#endif /* need port */
u32_t ip;
static char hexchars[] = "0123456789abcdef";
#if PRINTPKT_SUPPORT
struct buffer_info bufinfo;
#endif /* PRINTPKT_SUPPORT */
buf0 = buf;
--buflen;
while (buflen > 0) {
for (f = fmt; *f != '%' && *f != 0; ++f)
;
if (f > fmt) {
len = f - fmt;
if (len > buflen)
len = buflen;
memcpy(buf, fmt, len);
buf += len;
buflen -= len;
fmt = f;
}
if (*fmt == 0)
break;
c = *++fmt;
width = 0;
prec = -1;
fillch = ' ';
if (c == '0') {
fillch = '0';
c = *++fmt;
}
if (c == '*') {
width = va_arg(args, int);
c = *++fmt;
} else {
while (lwip_isdigit(c)) {
width = width * 10 + c - '0';
c = *++fmt;
}
}
if (c == '.') {
c = *++fmt;
if (c == '*') {
prec = va_arg(args, int);
c = *++fmt;
} else {
prec = 0;
while (lwip_isdigit(c)) {
prec = prec * 10 + c - '0';
c = *++fmt;
}
}
}
str = 0;
base = 0;
neg = 0;
++fmt;
switch (c) {
case 'l':
c = *fmt++;
switch (c) {
case 'd':
val = va_arg(args, long);
if ((long)val < 0) {
neg = 1;
val = (unsigned long)-(long)val;
}
base = 10;
break;
case 'u':
val = va_arg(args, unsigned long);
base = 10;
break;
default:
OUTCHAR('%');
OUTCHAR('l');
--fmt; /* so %lz outputs %lz etc. */
continue;
}
break;
case 'd':
i = va_arg(args, int);
if (i < 0) {
neg = 1;
val = -i;
} else
val = i;
base = 10;
break;
case 'u':
val = va_arg(args, unsigned int);
base = 10;
break;
case 'o':
val = va_arg(args, unsigned int);
base = 8;
break;
case 'x':
case 'X':
val = va_arg(args, unsigned int);
base = 16;
break;
#if 0 /* unused (and wrong on LLP64 systems) */
case 'p':
val = (unsigned long) va_arg(args, void *);
base = 16;
neg = 2;
break;
#endif /* unused (and wrong on LLP64 systems) */
case 's':
str = va_arg(args, char *);
break;
case 'c':
num[0] = va_arg(args, int);
num[1] = 0;
str = num;
break;
#if 0 /* do we always have strerror() in embedded ? */
case 'm':
str = strerror(errno);
break;
#endif /* do we always have strerror() in embedded ? */
case 'I':
ip = va_arg(args, u32_t);
ip = lwip_ntohl(ip);
ppp_slprintf(num, sizeof(num), "%d.%d.%d.%d", (ip >> 24) & 0xff,
(ip >> 16) & 0xff, (ip >> 8) & 0xff, ip & 0xff);
str = num;
break;
#if 0 /* need port */
case 't':
time(&t);
str = ctime(&t);
str += 4; /* chop off the day name */
str[15] = 0; /* chop off year and newline */
break;
#endif /* need port */
case 'v': /* "visible" string */
case 'q': /* quoted string */
quoted = c == 'q';
p = va_arg(args, unsigned char *);
if (p == NULL)
p = (const unsigned char *)"<NULL>";
if (fillch == '0' && prec >= 0) {
n = prec;
} else {
n = strlen((const char *)p);
if (prec >= 0 && n > prec)
n = prec;
}
while (n > 0 && buflen > 0) {
c = *p++;
--n;
if (!quoted && c >= 0x80) {
OUTCHAR('M');
OUTCHAR('-');
c -= 0x80;
}
if (quoted && (c == '"' || c == '\\'))
OUTCHAR('\\');
if (c < 0x20 || (0x7f <= c && c < 0xa0)) {
if (quoted) {
OUTCHAR('\\');
switch (c) {
case '\t': OUTCHAR('t'); break;
case '\n': OUTCHAR('n'); break;
case '\b': OUTCHAR('b'); break;
case '\f': OUTCHAR('f'); break;
default:
OUTCHAR('x');
OUTCHAR(hexchars[c >> 4]);
OUTCHAR(hexchars[c & 0xf]);
}
} else {
if (c == '\t')
OUTCHAR(c);
else {
OUTCHAR('^');
OUTCHAR(c ^ 0x40);
}
}
} else
OUTCHAR(c);
}
continue;
#if PRINTPKT_SUPPORT
case 'P': /* print PPP packet */
bufinfo.ptr = buf;
bufinfo.len = buflen + 1;
p = va_arg(args, unsigned char *);
n = va_arg(args, int);
ppp_format_packet(p, n, ppp_vslp_printer, &bufinfo);
buf = bufinfo.ptr;
buflen = bufinfo.len - 1;
continue;
#endif /* PRINTPKT_SUPPORT */
case 'B':
p = va_arg(args, unsigned char *);
for (n = prec; n > 0; --n) {
c = *p++;
if (fillch == ' ')
OUTCHAR(' ');
OUTCHAR(hexchars[(c >> 4) & 0xf]);
OUTCHAR(hexchars[c & 0xf]);
}
continue;
default:
*buf++ = '%';
if (c != '%')
--fmt; /* so %z outputs %z etc. */
--buflen;
continue;
}
if (base != 0) {
str = num + sizeof(num);
*--str = 0;
while (str > num + neg) {
*--str = hexchars[val % base];
val = val / base;
if (--prec <= 0 && val == 0)
break;
}
switch (neg) {
case 1:
*--str = '-';
break;
case 2:
*--str = 'x';
*--str = '0';
break;
default:
break;
}
len = num + sizeof(num) - 1 - str;
} else {
len = strlen(str);
if (prec >= 0 && len > prec)
len = prec;
}
if (width > 0) {
if (width > buflen)
width = buflen;
if ((n = width - len) > 0) {
buflen -= n;
for (; n > 0; --n)
*buf++ = fillch;
}
}
if (len > buflen)
len = buflen;
memcpy(buf, str, len);
buf += len;
buflen -= len;
}
*buf = 0;
return buf - buf0;
}