nativelibc/string/strtol.c

/*	A part of the Native C Library for Windows NT
	Copyright 2007-2015 PC GO Ld.

	This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

	This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
*/

#include <stdlib.h>
#include <errno.h>
#include <ctype.h>
#include <limits.h>

/*
#ifdef _LONGLONG
#define RETURN_TYPE long long int
#else
#define RETURN_TYPE long int
#endif
*/

#ifdef UNSIGNED
#define SIGN unsigned
#define strtol strtoul
#else
#define SIGN signed

#define DEF(TYPE, NAME) \
	static const TYPE NAME[] = {						\
		F(2), F(3), F(4), F(5), F(6), F(7), F(8), F(9), F(10),			\
		F(11), F(12), F(13), F(14), F(15), F(16), F(17), F(18), F(19), F(20),	\
		F(21), F(22), F(23), F(24), F(25), F(26), F(27), F(28), F(29), F(30),	\
		F(31), F(32), F(33), F(34), F(35), F(36)				\
	}

#define F(X) (ULONG_MAX / X)
DEF(unsigned long int, cutoff_tab);
#undef F

#define F(X) (ULONG_MAX % X)
DEF(unsigned char, cutlim_tab);
#undef F
#endif

//static const unsigned long int 

SIGN long int strtol(const char *nptr, char **endptr, int base) {
	int negative;
	register unsigned long int cutoff;
	register unsigned int cutlim;
	//register unsigned RETURN_TYPE i;
	register unsigned long int i;
	register const char *s;
	register unsigned char c;
	const char *save, *end;
	int overflow;

	if(base < 0 || base == 1 || base > 36) {
		errno = EINVAL;
		return 0;
	}

	save = s = nptr;
	while(isspace(*s)) s++;
	if(__builtin_expect(!*s, 0)) goto noconv;

	negative = 0;
	if(*s == '-') {
		negative = 1;
		s++;
	} else if(*s == '+') s++;

	if(*s == '0') {
		if(tolower(s[1]) == 'x' && ((base == 0 && (base = 16)) || base == 16)) {
			s += 2;
		} else if(base == 0) base = 8;
	} else if(base == 0) base = 10;

	save = s;

	end = NULL;

	cutoff = cutoff_tab[base - 2];
	cutlim = cutlim_tab[base - 2];

	overflow = 0;
	i = 0;
	c = *s;

	if(c) do {
		if(s == end) break;
		if(c >= '0' && c <= '9') c -= '0';
		else if(isalpha(c)) c = toupper(c) - 'A' + 10;
		else break;
		if((int)c >= base) break;
		if(i > cutoff || (i == cutoff && c > cutlim)) overflow = 1;
		else {
			i *= base;
			i += c;
		}
	} while((c = *++s));

	if(s == save) goto noconv;
	if(endptr) *endptr = (char *) s;

#ifndef UNSIGNED
	if(!overflow && i > (negative ?
	-((unsigned long int)(LONG_MIN + 1)) + 1 : (unsigned long int)LONG_MAX)) {
		overflow = 1;
	}
#endif

	if(__builtin_expect(overflow, 0)) {
		errno = ERANGE;
#ifdef UNSIGNED
		return ULONG_MAX;
#else
		return negative ? LONG_MIN : LONG_MAX;
#endif
	}
	return negative ? -i : i;

noconv:
	if(endptr) {
		if(save - nptr >= 2 && tolower(save[-1]) == 'x' && save[-2] == '0') {
			*endptr = (char *)(save - 1);
		} else {
			*endptr = (char *) nptr;
		}
	}
	return 0;
}

#ifndef UNSIGNED
#define UNSIGNED
#undef SIGN
#include "strtol.c"
#endif