static lua_Number readhexa (const char **s, lua_Number r, int *count) {
for (; lisxdigit(cast_uchar(**s)); (*s)++) { /* read integer part */
r = (r * cast_num(16.0)) + cast_num(luaO_hexavalue(cast_uchar(**s)));
(*count)++;
}
return r;
}
/*
** convert an hexadecimal numeric string to a number, following
** C99 specification for 'strtod'
*/
static lua_Number lua_strx2number (const char *s, char **endptr) {
lua_Number r = 0.0; /* result (accumulator) */
int sigdig = 0; /* number of significant digits */
int nosigdig = 0; /* number of non-significant digits */
int e = 0; /* exponent correction */
int neg = 0; /* 1 if number is negative */
int dot = 0; /* true after seen a dot */
*endptr = cast(char *, s); /* nothing is valid yet */
while (lisspace(cast_uchar(*s))) s++; /* skip initial spaces */
neg = isneg(&s); /* check signal */
if (!(*s == '0' && (*(s + 1) == 'x' || *(s + 1) == 'X'))) /* check '0x' */
return 0.0; /* invalid format (no '0x') */
for (s += 2; ; s++) { /* skip '0x' and read numeral */
if (*s == '.') {
if (dot) break; /* second dot? stop loop */
else dot = 1;
}
else if (lisxdigit(cast_uchar(*s))) {
if (sigdig == 0 && *s == '0') { /* non-significant zero? */
nosigdig++;
if (dot) e--; /* zero after dot? correct exponent */
}
else {
if (++sigdig <= MAXSIGDIG) { /* can read it without overflow? */
r = (r * cast_num(16.0)) + luaO_hexavalue(cast_uchar(*s));
if (dot) e--; /* decimal digit */
}
else /* too many digits; ignore */
if (!dot) e++; /* still count it for exponent */
}
}
else break; /* neither a dot nor a digit */
}
if (nosigdig + sigdig == 0) /* no digits? */
return 0.0; /* invalid format */
*endptr = cast(char *, s); /* valid up to here */
e *= 4; /* each digit multiplies/divides value by 2^4 */
if (*s == 'p' || *s == 'P') { /* exponent part? */
int exp1 = 0; /* exponent value */
int neg1; /* exponent signal */
s++; /* skip 'p' */
neg1 = isneg(&s); /* signal */
if (!lisdigit(cast_uchar(*s)))
return 0.0; /* invalid; must have at least one digit */
while (lisdigit(cast_uchar(*s))) /* read exponent */
exp1 = exp1 * 10 + *(s++) - '0';
if (neg1) exp1 = -exp1;
e += exp1;
*endptr = cast(char *, s); /* valid up to here */
}
static unsigned long readutf8esc (LexState *ls) {
unsigned long r;
int i = 4; /* chars to be removed: '\', 'u', '{', and first digit */
save_and_next(ls); /* skip 'u' */
esccheck(ls, ls->current == '{', "missing '{'");
r = gethexa(ls); /* must have at least one digit */
while ((save_and_next(ls), lisxdigit(ls->current))) {
i++;
r = (r << 4) + luaO_hexavalue(ls->current);
esccheck(ls, r <= 0x10FFFF, "UTF-8 value too large");
}
esccheck(ls, ls->current == '}', "missing '}'");
next(ls); /* skip '}' */
luaZ_buffremove(ls->buff, i); /* remove saved chars from buffer */
return r;
}
static int gethexa (LexState *ls) {
save_and_next(ls);
esccheck (ls, lisxdigit(ls->current), "hexadecimal digit expected");
return luaO_hexavalue(ls->current);
}
