octtoint.c

来自「网络时间协议NTP 源码 版本v4.2.0b 该源码用于linux平台下」· C语言 代码 · 共 36 行

/*
 * octtoint - convert an ascii string in octal to an unsigned
 *	      long, with error checking
 */
#include <stdio.h>
#include <ctype.h>

#include "ntp_stdlib.h"

int
octtoint(
	const char *str,
	u_long *ival
	)
{
	register u_long u;
	register const char *cp;

	cp = str;

	if (*cp == '\0')
	    return 0;

	u = 0;
	while (*cp != '\0') {
		if (!isdigit((int)*cp) || *cp == '8' || *cp == '9')
		    return 0;
		if (u >= 0x20000000)
		    return 0;	/* overflow */
		u <<= 3;
		u += *cp++ - '0';	/* ascii dependent */
	}
	*ival = u;
	return 1;
}