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ntp 4.2.6p5

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