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/* $OpenBSD: gcvt.c,v 1.4 2003/06/03 01:52:40 millert Exp $ */
/*
* Copyright (c) 2002 Todd C. Miller <Todd.Miller@courtesan.com>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND TODD C. MILLER DISCLAIMS ALL
* WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL TODD C. MILLER BE LIABLE
* FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
* OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#if defined(LIBC_SCCS) && !defined(lint)
static char rcsid[] = "$OpenBSD: gcvt.c,v 1.4 2003/06/03 01:52:40 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) {
/* Infinity or NaN, assume buffer is at least ndigit long. */
strlcpy(buf, digits, ndigit + 1);
return (buf);
}
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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