Return to dofptoa.c CVS log

Up to [ELWIX - Embedded LightWeight unIX -] / embedaddon / ntp / libntp

ntp 4.2.6p5

    1: /*
    2:  * dofptoa - do the grunge work to convert an fp number to ascii
    3:  */
    4: #include <stdio.h>
    5: 
    6: #include "ntp_fp.h"
    7: #include "lib_strbuf.h"
    8: #include "ntp_string.h"
    9: #include "ntp_stdlib.h"
   10: 
   11: char *
   12: dofptoa(
   13: 	u_fp fpv,
   14: 	int neg,
   15: 	short ndec,
   16: 	int msec
   17: 	)
   18: {
   19: 	register u_char *cp, *cpend;
   20: 	register u_long val;
   21: 	register short dec;
   22: 	u_char cbuf[12];
   23: 	u_char *cpdec;
   24: 	char *buf;
   25: 	char *bp;
   26: 
   27: 	/*
   28: 	 * Get a string buffer before starting
   29: 	 */
   30: 	LIB_GETBUF(buf);
   31: 
   32: 	/*
   33: 	 * Zero out the buffer
   34: 	 */
   35: 	memset((char *)cbuf, 0, sizeof cbuf);
   36: 
   37: 	/*
   38: 	 * Set the pointers to point at the first
   39: 	 * decimal place.  Get a local copy of the value.
   40: 	 */
   41: 	cp = cpend = &cbuf[5];
   42: 	val = fpv;
   43: 
   44: 	/*
   45: 	 * If we have to, decode the integral part
   46: 	 */
   47: 	if (!(val & 0xffff0000))
   48: 	    cp--;
   49: 	else {
   50: 		register u_short sv = (u_short)(val >> 16);
   51: 		register u_short tmp;
   52: 		register u_short ten = 10;
   53: 
   54: 		do {
   55: 			tmp = sv;
   56: 			sv = (u_short) (sv/ten);
   57: 			*(--cp) = (u_char)(tmp - ((sv<<3) + (sv<<1)));
   58: 		} while (sv != 0);
   59: 	}
   60: 
   61: 	/*
   62: 	 * Figure out how much of the fraction to do
   63: 	 */
   64: 	if (msec) {
   65: 		dec = (short)(ndec + 3);
   66: 		if (dec < 3)
   67: 		    dec = 3;
   68: 		cpdec = &cbuf[8];
   69: 	} else {
   70: 		dec = ndec;
   71: 		cpdec = cpend;
   72: 	}
   73: 
   74: 	if (dec > 6)
   75: 	    dec = 6;
   76: 	
   77: 	if (dec > 0) {
   78: 		do {
   79: 			val &= 0xffff;
   80: 			val = (val << 3) + (val << 1);
   81: 			*cpend++ = (u_char)(val >> 16);
   82: 		} while (--dec > 0);
   83: 	}
   84: 
   85: 	if (val & 0x8000) {
   86: 		register u_char *tp;
   87: 		/*
   88: 		 * Round it. Ick.
   89: 		 */
   90: 		tp = cpend;
   91: 		*(--tp) += 1;
   92: 		while (*tp >= 10) {
   93: 			*tp = 0;
   94: 			*(--tp) += 1;
   95: 		}
   96: 	}
   97: 
   98: 	/*
   99: 	 * Remove leading zeroes if necessary
  100: 	 */
  101: 	while (cp < (cpdec -1) && *cp == 0)
  102: 	    cp++;
  103: 	
  104: 	/*
  105: 	 * Copy it into the buffer, asciizing as we go.
  106: 	 */
  107: 	bp = buf;
  108: 	if (neg)
  109: 	    *bp++ = '-';
  110: 	
  111: 	while (cp < cpend) {
  112: 		if (cp == cpdec)
  113: 		    *bp++ = '.';
  114: 		*bp++ = (char)(*cp++ + '0');
  115: 	}
  116: 	*bp = '\0';
  117: 	return buf;
  118: }