strtol.c

来自「cfront是最开始c++语言到C语言的转换工具」· C语言 代码 · 共 81 行

/*ident	"@(#)cls4:tools/demangler/osrc/strtol.c	1.1" */

/*******************************************************************************
 
C++ source for the C++ Language System, Release 3.0.  This product
is a new release of the original cfront developed in the computer
science research center of AT&T Bell Laboratories.

Copyright (c) 1991 AT&T and UNIX System Laboratories, Inc.
Copyright (c) 1984, 1989, 1990 AT&T.  All Rights Reserved.

THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE of AT&T and UNIX System
Laboratories, Inc.  The copyright notice above does not evidence
any actual or intended publication of such source code.

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

/*
 * C++ Demangler Source Code
*/

#ifndef lint
static	char sccsid[] = "@(#)strtol.c 1.1 86/09/24 SMI"; /* from S5R2 2.1 */
#endif

/*LINTLIBRARY*/
#include <ctype.h>
#define DIGIT(x)	(isdigit(x) ? (x) - '0' : \
			islower(x) ? (x) + 10 - 'a' : (x) + 10 - 'A')
#define MBASE	('z' - 'a' + 1 + 10)

#include "elf_dem.h"

long
strtol(str, ptr, base)
register char *str;
char **ptr;
register int base;
{
	register long val;
	register int c;
	int xx, neg = 0;

	if (ptr != (char **)0)
		*ptr = str; /* in case no number is formed */
	if (base < 0 || base > MBASE)
		return (0); /* base is invalid -- should be a fatal error */
	if (!isalnum(c = *str)) {
		while (isspace(c))
			c = *++str;
		switch (c) {
		case '-':
			neg++;
		case '+': /* fall-through */
			c = *++str;
		}
	}
	if (base == 0)
		if (c != '0')
			base = 10;
		else if (str[1] == 'x' || str[1] == 'X')
			base = 16;
		else
			base = 8;
	/*
	 * for any base > 10, the digits incrementally following
	 *	9 are assumed to be "abc...z" or "ABC...Z"
	 */
	if (!isalnum(c) || (xx = DIGIT(c)) >= base)
		return (0); /* no number formed */
	if (base == 16 && c == '0' && isxdigit(str[2]) &&
	    (str[1] == 'x' || str[1] == 'X'))
		c = *(str += 2); /* skip over leading "0x" or "0X" */
	for (val = -DIGIT(c); isalnum(c = *++str) && (xx = DIGIT(c)) < base; )
		/* accumulate neg avoids surprises near MAXLONG */
		val = base * val - xx;
	if (ptr != (char **)0)
		*ptr = str;
	return (neg ? val : -val);
}