in libc/baselibc/src/vsscanf.c [68:400]
int vsscanf(const char *buffer, const char *format, va_list ap)
{
const char *p = format;
char ch;
unsigned char uc;
const char *q = buffer;
const char *qq;
uintmax_t val = 0;
int rank = rank_int; /* Default rank */
unsigned int width = UINT_MAX;
int base;
enum flags flags = 0;
enum {
st_normal, /* Ground state */
st_flags, /* Special flags */
st_width, /* Field width */
st_modifiers, /* Length or conversion modifiers */
st_match_init, /* Initial state of %[ sequence */
st_match, /* Main state of %[ sequence */
st_match_range, /* After - in a %[ sequence */
} state = st_normal;
char *sarg = NULL; /* %s %c or %[ string argument */
enum bail bail = bail_none;
int sign;
int converted = 0; /* Successful conversions */
unsigned long matchmap[((1 << CHAR_BIT) + (LONG_BIT - 1)) / LONG_BIT];
int matchinv = 0; /* Is match map inverted? */
unsigned char range_start = 0;
(void)sign;
while ((ch = *p++) && !bail) {
switch (state) {
case st_normal:
if (ch == '%') {
state = st_flags;
flags = 0;
rank = rank_int;
width = UINT_MAX;
} else if (isspace((unsigned char)ch)) {
q = skipspace(q);
} else {
if (*q == ch)
q++;
else
bail = bail_err; /* Match failure */
}
break;
case st_flags:
switch (ch) {
case '*':
flags |= FL_SPLAT;
break;
case '0'...'9':
width = (ch - '0');
state = st_width;
flags |= FL_WIDTH;
break;
default:
state = st_modifiers;
p--; /* Process this character again */
break;
}
break;
case st_width:
if (ch >= '0' && ch <= '9') {
width = width * 10 + (ch - '0');
} else {
state = st_modifiers;
p--; /* Process this character again */
}
break;
case st_modifiers:
switch (ch) {
/* Length modifiers - nonterminal sequences */
case 'h':
rank--; /* Shorter rank */
break;
case 'l':
rank++; /* Longer rank */
break;
case 'j':
rank = INTMAX_RANK;
break;
case 'z':
rank = SIZE_T_RANK;
break;
case 't':
rank = PTRDIFF_T_RANK;
break;
case 'L':
case 'q':
rank = rank_longlong; /* long double/long long */
break;
default:
/* Output modifiers - terminal sequences */
/* Next state will be normal */
state = st_normal;
/* Canonicalize rank */
if (rank < MIN_RANK)
rank = MIN_RANK;
else if (rank > MAX_RANK)
rank = MAX_RANK;
switch (ch) {
case 'P': /* Upper case pointer */
case 'p': /* Pointer */
rank = rank_ptr;
base = 0;
sign = 0;
goto scan_int;
case 'i': /* Base-independent integer */
base = 0;
sign = 1;
goto scan_int;
case 'd': /* Decimal integer */
base = 10;
sign = 1;
goto scan_int;
case 'o': /* Octal integer */
base = 8;
sign = 0;
goto scan_int;
case 'u': /* Unsigned decimal integer */
base = 10;
sign = 0;
goto scan_int;
case 'x': /* Hexadecimal integer */
case 'X':
base = 16;
sign = 0;
goto scan_int;
case 'n': /* # of characters consumed */
val = (q - buffer);
goto set_integer;
scan_int:
q = skipspace(q);
if (!*q) {
bail = bail_eof;
break;
}
val =
strntoumax(q, (char **)&qq, base,
width);
if (qq == q) {
bail = bail_err;
break;
}
q = qq;
if (!(flags & FL_SPLAT))
converted++;
/* fall through */
set_integer:
if (!(flags & FL_SPLAT)) {
switch (rank) {
case rank_char:
*va_arg(ap,
unsigned char *)
= val;
break;
case rank_short:
*va_arg(ap,
unsigned short
*) = val;
break;
case rank_int:
*va_arg(ap,
unsigned int *)
= val;
break;
case rank_long:
*va_arg(ap,
unsigned long *)
= val;
break;
case rank_longlong:
*va_arg(ap,
unsigned long
long *) = val;
break;
case rank_ptr:
*va_arg(ap, void **) =
(void *)
(uintptr_t)val;
break;
}
}
break;
case 'c': /* Character */
/* Default width == 1 */
width = (flags & FL_WIDTH) ? width : 1;
if (flags & FL_SPLAT) {
while (width--) {
if (!*q) {
bail = bail_eof;
break;
}
}
} else {
sarg = va_arg(ap, char *);
while (width--) {
if (!*q) {
bail = bail_eof;
break;
}
*sarg++ = *q++;
}
if (!bail)
converted++;
}
break;
case 's': /* String */
uc = 1; /* Anything nonzero */
if (flags & FL_SPLAT) {
while (width-- && (uc = *q) &&
!isspace(uc)) {
q++;
}
} else {
char *sp;
sp = sarg = va_arg(ap, char *);
while (width-- && (uc = *q) &&
!isspace(uc)) {
*sp++ = uc;
q++;
}
if (sarg != sp) {
/* Terminate output */
*sp = '\0';
converted++;
}
}
if (!uc)
bail = bail_eof;
break;
case '[': /* Character range */
sarg = (flags & FL_SPLAT) ? NULL
: va_arg(ap, char *);
state = st_match_init;
matchinv = 0;
memset(matchmap, 0, sizeof matchmap);
break;
case '%': /* %% sequence */
if (*q == '%')
q++;
else
bail = bail_err;
break;
default: /* Anything else */
/* Unknown sequence */
bail = bail_err;
break;
}
}
break;
case st_match_init: /* Initial state for %[ match */
if (ch == '^' && !(flags & FL_INV)) {
matchinv = 1;
} else {
set_bit(matchmap, (unsigned char)ch);
state = st_match;
}
break;
case st_match: /* Main state for %[ match */
if (ch == ']') {
goto match_run;
} else if (ch == '-') {
range_start = (unsigned char)ch;
state = st_match_range;
} else {
set_bit(matchmap, (unsigned char)ch);
}
break;
case st_match_range: /* %[ match after - */
if (ch == ']') {
/* - was last character */
set_bit(matchmap, (unsigned char)'-');
goto match_run;
} else {
int i;
for (i = range_start; i < (unsigned char)ch;
i++)
set_bit(matchmap, i);
state = st_match;
}
break;
match_run: /* Match expression finished */
qq = q;
uc = 1; /* Anything nonzero */
while (width && (uc = *q)
&& test_bit(matchmap, uc)^matchinv) {
if (sarg)
*sarg++ = uc;
q++;
}
if (q != qq && sarg) {
*sarg = '\0';
converted++;
} else {
bail = bail_err;
}
if (!uc)
bail = bail_eof;
break;
}
}
if (bail == bail_eof && !converted)
converted = -1; /* Return EOF (-1) */
return converted;
}