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Diffstat (limited to 'src/lib/libc/stdlib/gcvt.c')
-rw-r--r--src/lib/libc/stdlib/gcvt.c99
1 files changed, 99 insertions, 0 deletions
diff --git a/src/lib/libc/stdlib/gcvt.c b/src/lib/libc/stdlib/gcvt.c
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+++ b/src/lib/libc/stdlib/gcvt.c
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1/* $OpenBSD: gcvt.c,v 1.5 2003/06/17 21:56:24 millert Exp $ */
2
3/*
4 * Copyright (c) 2002, 2003 Todd C. Miller <Todd.Miller@courtesan.com>
5 *
6 * Permission to use, copy, modify, and distribute this software for any
7 * purpose with or without fee is hereby granted, provided that the above
8 * copyright notice and this permission notice appear in all copies.
9 *
10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17 *
18 * Sponsored in part by the Defense Advanced Research Projects
19 * Agency (DARPA) and Air Force Research Laboratory, Air Force
20 * Materiel Command, USAF, under agreement number F39502-99-1-0512.
21 */
22
23#if defined(LIBC_SCCS) && !defined(lint)
24static char rcsid[] = "$OpenBSD: gcvt.c,v 1.5 2003/06/17 21:56:24 millert Exp $";
25#endif /* LIBC_SCCS and not lint */
26
27#include <stdio.h>
28#include <stdlib.h>
29#include <string.h>
30
31extern char *__dtoa(double, int, int, int *, int *, char **);
32
33char *
34gcvt(double value, int ndigit, char *buf)
35{
36 char *digits, *dst, *src;
37 int i, decpt, sign;
38
39 if (ndigit == 0) {
40 buf[0] = '\0';
41 return (buf);
42 }
43
44 digits = __dtoa(value, 2, ndigit, &decpt, &sign, NULL);
45 if (decpt == 9999) {
46 /* Infinity or NaN, assume buffer is at least ndigit long. */
47 strlcpy(buf, digits, ndigit + 1);
48 return (buf);
49 }
50
51 dst = buf;
52 if (sign)
53 *dst++ = '-';
54
55 if (decpt < 0 || decpt > ndigit) {
56 /* exponential format */
57 if (--decpt < 0) {
58 sign = 1;
59 decpt = -decpt;
60 } else
61 sign = 0;
62 for (src = digits; *src != '\0'; )
63 *dst++ = *src++;
64 *dst++ = 'e';
65 if (sign)
66 *dst++ = '-';
67 else
68 *dst++ = '+';
69 if (decpt < 10) {
70 *dst++ = '0';
71 *dst++ = '0' + decpt;
72 *dst = '\0';
73 } else {
74 /* XXX - optimize */
75 for (sign = decpt, i = 0; (sign /= 10) != 0; i++)
76 sign /= 10;
77 while (decpt != 0) {
78 dst[i--] = '0' + decpt % 10;
79 decpt /= 10;
80 }
81 }
82 } else {
83 /* standard format */
84 for (i = 0, src = digits; i < decpt; i++) {
85 if (*src != '\0')
86 *dst++ = *src++;
87 else
88 *dst++ = '0';
89 }
90 if (*src != '\0') {
91 *dst++ = '.'; /* XXX - locale-specific (LC_NUMERIC) */
92 for (i = decpt; digits[i] != '\0'; i++) {
93 *dst++ = digits[i];
94 }
95 }
96 *dst = '\0';
97 }
98 return (buf);
99}