1/*	$NetBSD: atolfp.c,v 1.1.1.1 2009/12/13 16:55:01 kardel Exp $	*/
2
3/*
4 * atolfp - convert an ascii string to an l_fp number
5 */
6#include <stdio.h>
7#include <ctype.h>
8
9#include "ntp_fp.h"
10#include "ntp_string.h"
11#include "ntp_assert.h"
12
13/*
14 * Powers of 10
15 */
16static u_long ten_to_the_n[10] = {
17	0,
18	10,
19	100,
20	1000,
21	10000,
22	100000,
23	1000000,
24	10000000,
25	100000000,
26	1000000000,
27};
28
29
30int
31atolfp(
32	const char *str,
33	l_fp *lfp
34	)
35{
36	register const char *cp;
37	register u_long dec_i;
38	register u_long dec_f;
39	char *ind;
40	int ndec;
41	int isneg;
42	static const char *digits = "0123456789";
43
44	NTP_REQUIRE(str != NULL);
45
46	isneg = 0;
47	dec_i = dec_f = 0;
48	ndec = 0;
49	cp = str;
50
51	/*
52	 * We understand numbers of the form:
53	 *
54	 * [spaces][-|+][digits][.][digits][spaces|\n|\0]
55	 */
56	while (isspace((unsigned char)*cp))
57	    cp++;
58
59	if (*cp == '-') {
60		cp++;
61		isneg = 1;
62	}
63
64	if (*cp == '+')
65	    cp++;
66
67	if (*cp != '.' && !isdigit((unsigned char)*cp))
68	    return 0;
69
70	while (*cp != '\0' && (ind = strchr(digits, *cp)) != NULL) {
71		dec_i = (dec_i << 3) + (dec_i << 1);	/* multiply by 10 */
72		dec_i += (ind - digits);
73		cp++;
74	}
75
76	if (*cp != '\0' && !isspace((unsigned char)*cp)) {
77		if (*cp++ != '.')
78		    return 0;
79
80		while (ndec < 9 && *cp != '\0'
81		       && (ind = strchr(digits, *cp)) != NULL) {
82			ndec++;
83			dec_f = (dec_f << 3) + (dec_f << 1);	/* *10 */
84			dec_f += (ind - digits);
85			cp++;
86		}
87
88		while (isdigit((unsigned char)*cp))
89		    cp++;
90
91		if (*cp != '\0' && !isspace((unsigned char)*cp))
92		    return 0;
93	}
94
95	if (ndec > 0) {
96		register u_long tmp;
97		register u_long bit;
98		register u_long ten_fact;
99
100		ten_fact = ten_to_the_n[ndec];
101
102		tmp = 0;
103		bit = 0x80000000;
104		while (bit != 0) {
105			dec_f <<= 1;
106			if (dec_f >= ten_fact) {
107				tmp |= bit;
108				dec_f -= ten_fact;
109			}
110			bit >>= 1;
111		}
112		if ((dec_f << 1) > ten_fact)
113		    tmp++;
114		dec_f = tmp;
115	}
116
117	if (isneg)
118	    M_NEG(dec_i, dec_f);
119
120	lfp->l_ui = dec_i;
121	lfp->l_uf = dec_f;
122	return 1;
123}
124