/*******************************************************************************

    Copyright(C) Jonas 'Sortie' Termansen 2011, 2013.

    This file is part of the Sortix C Library.

    The Sortix C Library is free software: you can redistribute it and/or modify
    it under the terms of the GNU Lesser General Public License as published by
    the Free Software Foundation, either version 3 of the License, or (at your
    option) any later version.

    The Sortix C Library 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 Lesser General Public
    License for more details.

    You should have received a copy of the GNU Lesser General Public License
    along with the Sortix C Library. If not, see <http://www.gnu.org/licenses/>.

    stdlib/strtol.cpp
    Converts integers represented as strings to binary representation.

*******************************************************************************/

#ifndef STRTOL
#define STRTOL strtol
#define STRTOL_INT long
#define STRTOL_INT_IS_UNSIGNED false
#endif

#include <ctype.h>
#include <inttypes.h>
#include <stddef.h>
#include <stdlib.h>

static int Debase(char c)
{
	if ( '0' <= c && c <= '9' )
		return c - '0';
	if ( 'a' <= c && c <= 'z' )
		return 10 + c - 'a';
	if ( 'A' <= c && c <= 'Z' )
		return 10 + c - 'A';
	return -1;
}

template <class INT, bool UNSIGNED>
INT ParseInteger(const char* str, char** endptr, int base)
{
	const char* origstr = str;
	int origbase = base;
	while ( isspace(*str) ) { str++; }
	if ( base < 0 || 36 < base )
	{
		if ( endptr )
			*endptr = (char*) str;
		return 0;
	}
	INT result = 0;
	bool negative = false;
	char c = *str;
	if ( !UNSIGNED && c == '-' )
		str++, negative = true;
	if ( !UNSIGNED && c == '+' )
		str++, negative = false;
	if ( !base && str[0] == '0' )
	{
		if ( str[1] == 'x' || str[1] == 'X' )
			str += 2, base = 16;
		else if ( 0 <= Debase(str[1]) && Debase(str[1]) < 8 )
			str++, base = 8;
	}
	if ( !base )
		base = 10;
	if ( origbase == 16 && str[0] == '0' && (str[1] == 'x' || str[1] == 'X') )
		str += 2;
	size_t numconvertedchars = 0;
	while ( (c = *str ) )
	{
		int val = Debase(c);
		if ( val < 0 )
			break;
		if ( base <= val )
			break;
		if ( !UNSIGNED && negative )
			val = -val;
		// TODO: Detect overflow!
		result = result * (INT) base + (INT) val;
		str++;
		numconvertedchars++;
	}
	if ( !numconvertedchars )
		str = origstr, result = 0;
	if ( endptr )
		*endptr = (char*) str;
	return result;
}

extern "C" STRTOL_INT STRTOL(const char* str, char** endptr, int base)
{
	return ParseInteger<STRTOL_INT, STRTOL_INT_IS_UNSIGNED>(str, endptr, base);
}