/*      $OpenBSD: ecvt.c,v 1.11 2019/01/25 00:19:25 millert Exp $       */

/*
 * Copyright (c) 2002, 2006 Todd C. Miller <millert@openbsd.org>
 *
 * 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 THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR 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.
 *
 * Sponsored in part by the Defense Advanced Research Projects
 * Agency (DARPA) and Air Force Research Laboratory, Air Force
 * Materiel Command, USAF, under agreement number F39502-99-1-0512.
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "gdtoa.h"

static char *__cvt(double, int, int *, int *, int, int);

static char *
__cvt(double value, int ndigit, int *decpt, int *sign, int fmode, int pad)
{
        static char *s;
        char *p, *rve, c;
        size_t siz;

        if (ndigit == 0) {
                *sign = value < 0.0;
                *decpt = 0;
                return ("");
        }

        free(s);
        s = NULL;

        if (ndigit < 0)
                siz = -ndigit + 1;
        else
                siz = ndigit + 1;


        /* __dtoa() doesn't allocate space for 0 so we do it by hand */
        if (value == 0.0) {
                *decpt = 1 - fmode;     /* 1 for 'e', 0 for 'f' */
                *sign = 0;
                if ((rve = s = malloc(siz)) == NULL)
                        return(NULL);
                *rve++ = '0';
                *rve = '\0';
        } else {
                p = __dtoa(value, fmode + 2, ndigit, decpt, sign, &rve);
                if (p == NULL)
                        return (NULL);
                if (*decpt == 9999) {
                        /* Infinity or Nan, convert to inf or nan like printf */
                        *decpt = 0;
                        c = *p;
                        __freedtoa(p);
                        return(c == 'I' ? "inf" : "nan");
                }
                /* Make a local copy and adjust rve to be in terms of s */
                if (pad && fmode)
                        siz += *decpt;
                if ((s = malloc(siz)) == NULL) {
                        __freedtoa(p);
                        return(NULL);
                }
                (void) strlcpy(s, p, siz);
                rve = s + (rve - p);
                __freedtoa(p);
        }

        /* Add trailing zeros */
        if (pad) {
                siz -= rve - s;
                while (--siz)
                        *rve++ = '0';
                *rve = '\0';
        }

        return(s);
}

char *
ecvt(double value, int ndigit, int *decpt, int *sign)
{
        return(__cvt(value, ndigit, decpt, sign, 0, 1));
}

char *
fcvt(double value, int ndigit, int *decpt, int *sign)
{
        return(__cvt(value, ndigit, decpt, sign, 1, 1));
}