tc_strtol.c

T-kernel 的extension源代码

/*
 *----------------------------------------------------------------------
 *    T-Kernel / Standard Extension
 *
 *    Copyright (C) 2006 by Ken Sakamura. All rights reserved.
 *    T-Kernel / Standard Extension is distributed 
 *      under the T-License for T-Kernel / Standard Extension.
 *----------------------------------------------------------------------
 *
 *    Version:   1.00.00
 *    Released by T-Engine Forum(http://www.t-engine.org) at 2006/8/11.
 *
 *----------------------------------------------------------------------
 */

/*
 *	tc_strtol.C (libtcstr)
 *
 *	base == 0  : +/-<decimal> | +/-0<octal> | +/-0X<hexadecimal> | +/-0x<hexadecimal>
 *	base == 16 : +/-<hexadecimal> | +/-0X<hexadecimal> | +/-0x<hexadecimal>
 *	Other	   : +/-<base n>
 *	(base <= 36)
 *
 *	The first space is skipped.
 *	If ps != NULL, a pointer to the next string is set.
 */

#include <basic.h>
#include <tcode.h>

#define TSD_TST_VAL_8	8
#define TSD_TST_VAL_9	9
#define TSD_TST_VAL_10	10
#define TSD_TST_VAL_16	16

long	tc_strtol(const TC *str, TC **ptr, int base)
{
	W	n;
	W	sign = 0;
	long	val = 0;

	while ((*str == TK_KSP )||( *str == '\t')) {
		str++;
	}

	if (*str == TK_MINS) {
		sign++;
		str++;
	} else if ( *str == TK_PLUS) {
		str++;
	}

	if (base <= 1) {
		base = TSD_TST_VAL_10;
		if (*(str++) == TK_0) {
			base = TSD_TST_VAL_8;
			if ((*str == TK_X )||( *str == TK_x)) {
				base = TSD_TST_VAL_16;
			}
		}
		str--;
	}

	if (base <= TSD_TST_VAL_10 ) {
		while (((n = *(str++) - TK_0) >= 0) && (n < base)) {
			val = (val * base) + n;
		}
	} else {
		if (base == TSD_TST_VAL_16) {
			if ((*(str++) == TK_0) &&
				((*str == TK_X )||( *str == TK_x))) {
				str++;
			} else {
				str--;
			}
		}
		while ((n = *(str++) - TK_0) >= 0) {
			if (n > TSD_TST_VAL_9) {
				n -= (TK_A - TK_0);
				if (n < 0) {
					break;
				}
				if ( n >= (TK_a - TK_A)) {
					n -= (TK_a - TK_A);
				}
				n += TSD_TST_VAL_10;
				if ( n >= base) {
					break;
				}
			}
			val = (val * base) + n;
		}
	}
	if (ptr != 0) {
		*ptr = (TC *) (str - 1);
	}
	return (sign != 0) ? -val : val;
}