asprintf.c
1/*
2 * Copyright (c) 2004 Darren Tucker.
3 *
4 * Based originally on asprintf.c from OpenBSD:
5 * Copyright (c) 1997 Todd C. Miller <Todd.Miller@courtesan.com>
6 *
7 * Permission to use, copy, modify, and distribute this software for any
8 * purpose with or without fee is hereby granted, provided that the above
9 * copyright notice and this permission notice appear in all copies.
10 *
11 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
12 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
13 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
14 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
15 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
16 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
17 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
18 */
19
20#include "pconfig.h"
21
22#ifndef HAVE_ASPRINTF
23
24#include <errno.h>
25#include <limits.h> /* for INT_MAX */
26#include <stdarg.h>
27#include <stdio.h> /* for vsnprintf */
28#include <stdlib.h>
29
30#define INIT_SZ 128
31
32int
33vasprintf(char **str, const char *fmt, va_list ap)
34{
35 int ret;
36 va_list ap2;
37 char *string, *newstr;
38 size_t len;
39
40 if ((string = malloc(INIT_SZ)) == NULL)
41 goto fail;
42
43 va_copy(ap2, ap);
44 ret = vsnprintf(string, INIT_SZ, fmt, ap2);
45 va_end(ap2);
46 if (ret >= 0 && ret < INIT_SZ) { /* succeeded with initial alloc */
47 *str = string;
48 } else if (ret == INT_MAX || ret < 0) { /* Bad length */
49 free(string);
50 goto fail;
51 } else { /* bigger than initial, realloc allowing for nul */
52 len = (size_t)ret + 1;
53 if ((newstr = realloc(string, len)) == NULL) {
54 free(string);
55 goto fail;
56 }
57 va_copy(ap2, ap);
58 ret = vsnprintf(newstr, len, fmt, ap2);
59 va_end(ap2);
60 if (ret < 0 || (size_t)ret >= len) { /* failed with realloc'ed string */
61 free(newstr);
62 goto fail;
63 }
64 *str = newstr;
65 }
66 return (ret);
67
68fail:
69 *str = NULL;
70 errno = ENOMEM;
71 return (-1);
72}
73
74int asprintf(char **str, const char *fmt, ...)
75{
76 va_list ap;
77 int ret;
78
79 *str = NULL;
80 va_start(ap, fmt);
81 ret = vasprintf(str, fmt, ap);
82 va_end(ap);
83
84 return ret;
85}
86#endif
