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-rw-r--r--src/lib/libc/stdlib/gcvt.c111
1 files changed, 111 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 1.10 2006/10/29 18:45:56 deraadt Exp $ */
2
3/*
4 * Copyright (c) 2002, 2003, 2006 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#include <locale.h>
24#include <stdio.h>
25#include <stdlib.h>
26#include <string.h>
27
28extern char *__dtoa(double, int, int, int *, int *, char **);
29extern void __freedtoa(char *);
30
31char *
32gcvt(double value, int ndigit, char *buf)
33{
34 char *digits, *dst, *src;
35 int i, decpt, sign;
36 struct lconv *lconv;
37
38 lconv = localeconv();
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 /*
47 * Infinity or NaN, convert to inf or nan with sign.
48 * We assume the buffer is at least ndigit long.
49 */
50 snprintf(buf, ndigit + 1, "%s%s", sign ? "-" : "",
51 *digits == 'I' ? "inf" : "nan");
52 __freedtoa(digits);
53 return (buf);
54 }
55
56 dst = buf;
57 if (sign)
58 *dst++ = '-';
59
60 if (decpt < 0 || decpt > ndigit) {
61 /* exponential format (e.g. 1.2345e+13) */
62 if (--decpt < 0) {
63 sign = 1;
64 decpt = -decpt;
65 } else
66 sign = 0;
67 src = digits;
68 *dst++ = *src++;
69 *dst++ = *lconv->decimal_point;
70 while (*src != '\0')
71 *dst++ = *src++;
72 *dst++ = 'e';
73 if (sign)
74 *dst++ = '-';
75 else
76 *dst++ = '+';
77 if (decpt < 10) {
78 *dst++ = '0';
79 *dst++ = '0' + decpt;
80 *dst = '\0';
81 } else {
82 /* XXX - optimize */
83 for (sign = decpt, i = 0; (sign /= 10) != 0; i++)
84 continue;
85 dst[i + 1] = '\0';
86 while (decpt != 0) {
87 dst[i--] = '0' + decpt % 10;
88 decpt /= 10;
89 }
90 }
91 } else {
92 /* standard format */
93 for (i = 0, src = digits; i < decpt; i++) {
94 if (*src != '\0')
95 *dst++ = *src++;
96 else
97 *dst++ = '0';
98 }
99 if (*src != '\0') {
100 if (src == digits)
101 *dst++ = '0'; /* zero before decimal point */
102 *dst++ = *lconv->decimal_point;
103 for (i = decpt; digits[i] != '\0'; i++) {
104 *dst++ = digits[i];
105 }
106 }
107 *dst = '\0';
108 }
109 __freedtoa(digits);
110 return (buf);
111}