121 lines
1.8 KiB
C
121 lines
1.8 KiB
C
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/* $NetBSD: atolfp.c,v 1.1.1.1 2000/03/29 12:38:49 simonb Exp $ */
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/*
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* atolfp - convert an ascii string to an l_fp number
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*/
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#include <stdio.h>
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#include <ctype.h>
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#include "ntp_fp.h"
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#include "ntp_string.h"
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/*
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* Powers of 10
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*/
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static u_long ten_to_the_n[10] = {
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0,
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10,
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100,
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1000,
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10000,
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100000,
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1000000,
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10000000,
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100000000,
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1000000000,
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};
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int
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atolfp(
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const char *str,
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l_fp *lfp
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)
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{
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register const char *cp;
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register u_long dec_i;
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register u_long dec_f;
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char *ind;
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int ndec;
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int isneg;
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static const char *digits = "0123456789";
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isneg = 0;
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dec_i = dec_f = 0;
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ndec = 0;
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cp = str;
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/*
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* We understand numbers of the form:
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*
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* [spaces][-|+][digits][.][digits][spaces|\n|\0]
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*/
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while (isspace((int)*cp))
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cp++;
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if (*cp == '-') {
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cp++;
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isneg = 1;
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}
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if (*cp == '+')
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cp++;
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if (*cp != '.' && !isdigit((int)*cp))
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return 0;
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while (*cp != '\0' && (ind = strchr(digits, *cp)) != NULL) {
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dec_i = (dec_i << 3) + (dec_i << 1); /* multiply by 10 */
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dec_i += (ind - digits);
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cp++;
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}
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if (*cp != '\0' && !isspace((int)*cp)) {
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if (*cp++ != '.')
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return 0;
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while (ndec < 9 && *cp != '\0'
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&& (ind = strchr(digits, *cp)) != NULL) {
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ndec++;
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dec_f = (dec_f << 3) + (dec_f << 1); /* *10 */
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dec_f += (ind - digits);
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cp++;
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}
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while (isdigit((int)*cp))
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cp++;
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if (*cp != '\0' && !isspace((int)*cp))
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return 0;
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}
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if (ndec > 0) {
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register u_long tmp;
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register u_long bit;
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register u_long ten_fact;
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ten_fact = ten_to_the_n[ndec];
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tmp = 0;
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bit = 0x80000000;
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while (bit != 0) {
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dec_f <<= 1;
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if (dec_f >= ten_fact) {
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tmp |= bit;
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dec_f -= ten_fact;
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}
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bit >>= 1;
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}
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if ((dec_f << 1) > ten_fact)
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tmp++;
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dec_f = tmp;
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}
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if (isneg)
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M_NEG(dec_i, dec_f);
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lfp->l_ui = dec_i;
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lfp->l_uf = dec_f;
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return 1;
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}
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