Blame |
Last modification |
View Log
| RSS feed
/*-
* Copyright (c) 1996 Peter Wemm <peter@freebsd.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
*/
#if defined(LIBC_RCS) && !defined(lint)
static char rcsid
[] = "$\Id: vasprintf.c,v 1.3 1996/07/28 16:16:11 peter Exp $";
#endif /* LIBC_RCS and not lint */
#include <stdio.h>
#include <stdlib.h>
#if __STDC__
#include <stdarg.h>
#else
#include <varargs.h>
#endif
#define CHUNK_SPARE 128 /* how much spare to allocate to avoid realloc calls */
struct bufcookie
{
char *base
; /* start of buffer */
size_t size
;
size_t left
;
};
static int writehook __P
((void *cookie
, const char *, int));
static int
writehook
(cookie
, buf
, len
)
void *cookie
;
const char *buf
;
int len
;
{
struct bufcookie
*h
= (struct bufcookie
*)cookie
;
char *newbuf
;
if (len
== 0)
return 0;
if (len
> h
->left
) {
/* grow malloc region */
/*
* XXX this is linearly expanded, which is slow for obscenely
* large strings.
*/
h
->left
= h
->left
+ len
+ CHUNK_SPARE
;
h
->size
= h
->size
+ len
+ CHUNK_SPARE
;
newbuf
= realloc(h
->base
, h
->size
);
if (newbuf
== NULL
) {
free(h
->base
);
h
->base
= NULL
;
return (-1);
} else
h
->base
= newbuf
;
}
/* "write" it */
(void)memcpy(h
->base
+ h
->size
- h
->left
, buf
, (size_t)len
);
h
->left
-= len
;
return (len
);
}
int
vasprintf
(str
, fmt
, ap
)
char **str
;
const char *fmt
;
va_list ap
;
{
int ret
;
FILE
*f
;
struct bufcookie h
;
h.
base = malloc(CHUNK_SPARE
);
if (h.
base == NULL
)
return (-1);
h.
size = CHUNK_SPARE
;
h.
left = CHUNK_SPARE
;
f
= funopen
(&h
, NULL
, writehook
, NULL
, NULL
);
if (f
== NULL
) {
free(h.
base);
return (-1);
}
ret
= vfprintf(f
, fmt
, ap
);
fclose(f
);
if (ret
< 0) {
free(h.
base);
return (-1);
}
if (h.
base == NULL
) /* failed to realloc in writehook */
return (-1);
h.
base[h.
size - h.
left] = '\0';
*str
= realloc(h.
base, (size_t)(h.
size - h.
left + 1));
if (*str
== NULL
) /* failed to realloc it to actual size */
*str
= h.
base; /* return oversize buffer */
return (ret
);
}