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      1 /*	$NetBSD: hextolfp.c,v 1.8 2020/05/25 20:47:24 christos Exp $	*/
      2 
      3 /*
      4  * hextolfp - convert an ascii hex string to an l_fp number
      5  */
      6 #include <config.h>
      7 #include <stdio.h>
      8 #include <ctype.h>
      9 
     10 #include "ntp_fp.h"
     11 #include "ntp_string.h"
     12 #include "ntp_stdlib.h"
     13 
     14 int
     15 hextolfp(
     16 	const char *str,
     17 	l_fp *lfp
     18 	)
     19 {
     20 	register const char *cp;
     21 	register const char *cpstart;
     22 	register u_long dec_i;
     23 	register u_long dec_f;
     24 	char *ind = NULL;
     25 	static const char *digits = "0123456789abcdefABCDEF";
     26 
     27 	dec_i = dec_f = 0;
     28 	cp = str;
     29 
     30 	/*
     31 	 * We understand numbers of the form:
     32 	 *
     33 	 * [spaces]8_hex_digits[.]8_hex_digits[spaces|\n|\0]
     34 	 */
     35 	while (isspace((unsigned char)*cp))
     36 	    cp++;
     37 
     38 	cpstart = cp;
     39 	while (*cp != '\0' && (cp - cpstart) < 8 &&
     40 	       (ind = strchr(digits, *cp)) != NULL) {
     41 		dec_i = dec_i << 4;	/* multiply by 16 */
     42 		dec_i += ((ind - digits) > 15)
     43 			? (u_long)(ind - digits - 6)
     44 			: (u_long)(ind - digits);
     45 		cp++;
     46 	}
     47 
     48 	if ((cp - cpstart) < 8 || ind == NULL)
     49 	    return 0;
     50 	if (*cp == '.')
     51 	    cp++;
     52 
     53 	cpstart = cp;
     54 	while (*cp != '\0' && (cp - cpstart) < 8 &&
     55 	       (ind = strchr(digits, *cp)) != NULL) {
     56 		dec_f = dec_f << 4;	/* multiply by 16 */
     57 		dec_f += ((ind - digits) > 15)
     58 			? (u_long)(ind - digits - 6)
     59 			: (u_long)(ind - digits);
     60 		cp++;
     61 	}
     62 
     63 	if ((cp - cpstart) < 8 || ind == NULL)
     64 	    return 0;
     65 
     66 	if (*cp != '\0' && !isspace((unsigned char)*cp))
     67 	    return 0;
     68 
     69 	lfp->l_ui = dec_i;
     70 	lfp->l_uf = dec_f;
     71 	return 1;
     72 }
     73