xref: /freebsd/lib/libc/stdlib/strfromd.c (revision d15f2551b25f79ddcbe289faa95e655100b952da)
1 /*
2  * Copyright (c) 2026 Faraz Vahedi <kfv@kfv.io>
3  *
4  * SPDX-License-Identifier: BSD-2-Clause
5  */
6 
7 #include <ctype.h>
8 #include <stdlib.h>
9 
10 #include "strfrom.h"
11 
12 int
13 strfromd(char * __restrict s, size_t n, const char * __restrict fmt, double fp)
14 {
15 	char conv, lc, *digits, *dend;
16 	int prec, decpt, signflag, ret, mode, ndig_req;
17 
18 	conv = __sf_parse_fmt(fmt, &prec);
19 	if (conv == '\0')
20 		return (__sf_edoofus(s, n));
21 	lc = tolower((unsigned char)conv);
22 
23 	if (lc == 'a') {
24 		digits = __hdtoa(fp, __sf_xdigits(conv),
25 		    prec >= 0 ? prec + 1 : -1, &decpt, &signflag, &dend);
26 		ret = __sf_render_hex(s, n, conv, prec, digits, dend, decpt,
27 		    signflag);
28 		freedtoa(digits);
29 		return (ret);
30 	}
31 
32 	if (prec < 0)
33 		prec = 6;
34 
35 	__sf_decimal_mode(lc, prec, &mode, &ndig_req);
36 
37 	digits = dtoa(fp, mode, ndig_req, &decpt, &signflag, &dend);
38 
39 	ret = __sf_render_decimal(s, n, conv, lc, prec, digits, dend, decpt,
40 	    signflag, decpt == 9999);
41 
42 	freedtoa(digits);
43 
44 	return (ret);
45 }
46