# dtostre.c

/* Copyright (c) 2005, Dmitry Xmelkov

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

* Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
* 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.
* Neither the name of the copyright holders nor the names of
contributors may be used to endorse or promote products derived
from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 COPYRIGHT OWNER OR CONTRIBUTORS 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. */

/* $Id$ */

#include <stdlib.h>
#include <avr/pgmspace.h>
#include "ftoa_engine.h"
#include "sectionname.h"

ATTRIBUTE_CLIB_SECTION
char *
dtostre (double val, char *sbeg, unsigned char prec, unsigned char flags)
{
__attribute__((progmem)) static const char str_nan[2][4] =
{"nan", "NAN"};
__attribute__((progmem)) static const char str_inf[2][sizeof(str_nan[0])] =
{"inf", "INF"};
char *d;            /* dst  */
const char *s;              /* src  */
signed char exp;
unsigned char vtype;

if (prec > 7) prec = 7;

exp = __ftoa_engine (val, sbeg, prec, 0);
d = s = sbeg;
vtype = *s++;

if ((vtype & FTOA_MINUS) && !(vtype & FTOA_NAN))    /* like 'Glibc' */
*d++ = '-';
else if (flags & DTOSTR_PLUS_SIGN)
*d++ = '+';
else if (flags & DTOSTR_ALWAYS_SIGN)
*d++ = ' ';

if (vtype & FTOA_NAN) {
s = str_nan[0];
goto copy;
}

if (vtype & FTOA_INF) {
s = str_inf[0];
copy:
if (flags & DTOSTR_UPPERCASE)
s += sizeof(str_nan[0]);
strcpy_P (d, s);
goto ret;
}

/* mantissa */
if ( (*d++ = *s++) != '1')
vtype &= ~FTOA_CARRY;           /* for possible exponent "-00"  */
if (prec) {
unsigned char c1, c2;
c1 = '.';
do {
c2 = *s++;
*d++ = c1;
c1 = c2;
} while (--prec);
*d++ = c1;
}

/* exponent */
*d++ = (flags & DTOSTR_UPPERCASE) ? 'E' : 'e';
if (exp < 0) {
*d++ = '-';
exp = -exp;
} else if (exp == 0 && (vtype & FTOA_CARRY) != 0) {
*d++ = '-';
} else {
*d++ = '+';
}
for (prec = '0';  exp >= 10;  exp -= 10)
prec += 1;
*d++ = prec;
*d++ = '0' + exp;
*d = 0;

ret:
return sbeg;
}
/*** end of file ***/