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/* $OpenBSD: gcvt.c,v 1.1 2002/12/02 15:38:54 millert Exp $ */
/*
* Copyright (c) 2002 Todd C. Miller <Todd.Miller@courtesan.com>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
* THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#if defined(LIBC_SCCS) && !defined(lint)
static char rcsid[] = "$OpenBSD: gcvt.c,v 1.1 2002/12/02 15:38:54 millert Exp $";
#endif /* LIBC_SCCS and not lint */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
extern char *__dtoa(double, int, int, int *, int *, char **);
char *
gcvt(double value, int ndigit, char *buf)
{
char *digits, *dst, *src;
int i, decpt, sign;
if (ndigit == 0) {
buf[0] = '\0';
return (buf);
}
digits = __dtoa(value, 2, ndigit, &decpt, &sign, NULL);
if (decpt == 9999)
return (strcpy(buf, digits));
dst = buf;
if (sign)
*dst++ = '-';
if (decpt < 0 || decpt > ndigit) {
/* exponential format */
if (--decpt < 0) {
sign = 1;
decpt = -decpt;
} else
sign = 0;
for (src = digits; *src != '\0'; )
*dst++ = *src++;
*dst++ = 'e';
if (sign)
*dst++ = '-';
else
*dst++ = '+';
if (decpt < 10) {
*dst++ = '0';
*dst++ = '0' + decpt;
*dst = '\0';
} else {
/* XXX - optimize */
for (sign = decpt, i = 0; (sign /= 10) != 0; i++)
sign /= 10;
while (decpt != 0) {
dst[i--] = '0' + decpt % 10;
decpt /= 10;
}
}
} else {
/* standard format */
for (i = 0, src = digits; i < decpt; i++) {
if (*src != '\0')
*dst++ = *src++;
else
*dst++ = '0';
}
if (*src != '\0') {
*dst++ = '.'; /* XXX - locale-specific (LC_NUMERIC) */
for (i = decpt; digits[i] != '\0'; i++) {
*dst++ = digits[i];
}
}
*dst = '\0';
}
return (buf);
}
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