438 static int nextc (RN *rn) {  in nextc()  argument
439   if (l_unlikely(rn->n >= L_MAXLENNUM)) {  /* buffer overflow? */  in nextc()
440     rn->buff[0] = '\0';  /* invalidate result */  in nextc()
444     rn->buff[rn->n++] = rn->c;  /* save current char */  in nextc()
445     rn->c = l_getc(rn->f);  /* read next one */  in nextc()
454 static int test2 (RN *rn, const char *set) {  in test2()  argument
455   if (rn->c == set[0] || rn->c == set[1])  in test2()
456     return nextc(rn);  in test2()
464 static int readdigits (RN *rn, int hex) {  in readdigits()  argument
466   while ((hex ? isxdigit(rn->c) : isdigit(rn->c)) && nextc(rn))  in readdigits()
478   RN rn;  in read_number()  local
482   rn.f = f; rn.n = 0;  in read_number()
485   l_lockfile(rn.f);  in read_number()
486   do { rn.c = l_getc(rn.f); } while (isspace(rn.c));  /* skip spaces */  in read_number()
487   test2(&rn, "-+");  /* optional sign */  in read_number()
488   if (test2(&rn, "00")) {  in read_number()
489     if (test2(&rn, "xX")) hex = 1;  /* numeral is hexadecimal */  in read_number()
492   count += readdigits(&rn, hex);  /* integral part */  in read_number()
493   if (test2(&rn, decp))  /* decimal point? */  in read_number()
494     count += readdigits(&rn, hex);  /* fractional part */  in read_number()
495   if (count > 0 && test2(&rn, (hex ? "pP" : "eE"))) {  /* exponent mark? */  in read_number()
496     test2(&rn, "-+");  /* exponent sign */  in read_number()
497     readdigits(&rn, 0);  /* exponent digits */  in read_number()
499   ungetc(rn.c, rn.f);  /* unread look-ahead char */  in read_number()
500   l_unlockfile(rn.f);  in read_number()
501   rn.buff[rn.n] = '\0';  /* finish string */  in read_number()
502   if (l_likely(lua_stringtonumber(L, rn.buff)))  in read_number()