glibc/stdio/vasprintf.c

86 lines
2.5 KiB
C

/* Copyright (C) 1991, 1992, 1997 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#include <stddef.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
/* Enlarge STREAM's buffer. */
static void
enlarge_buffer (FILE *stream, int c)
{
ptrdiff_t bufp_offset = stream->__bufp - stream->__buffer;
char *newbuf;
stream->__bufsize += 100;
newbuf = (char *) realloc ((void *) stream->__buffer, stream->__bufsize);
if (newbuf == NULL)
{
free ((void *) stream->__buffer);
stream->__buffer = stream->__bufp
= stream->__put_limit = stream->__get_limit = NULL;
stream->__error = 1;
}
else
{
stream->__buffer = newbuf;
stream->__bufp = stream->__buffer + bufp_offset;
stream->__get_limit = stream->__put_limit;
stream->__put_limit = stream->__buffer + stream->__bufsize;
if (c != EOF)
*stream->__bufp++ = (unsigned char) c;
}
}
/* Write formatted output from FORMAT to a string which is
allocated with malloc and stored in *STRING_PTR. */
int
vasprintf (char **string_ptr,
const char *format,
va_list args)
{
FILE f;
int done;
memset ((void *) &f, 0, sizeof (f));
f.__magic = _IOMAGIC;
f.__bufsize = 100;
f.__buffer = (char *) malloc (f.__bufsize);
if (f.__buffer == NULL)
return -1;
f.__bufp = f.__buffer;
f.__put_limit = f.__buffer + f.__bufsize;
f.__mode.__write = 1;
f.__room_funcs.__output = enlarge_buffer;
f.__seen = 1;
done = vfprintf (&f, format, args);
if (done < 0)
return done;
*string_ptr = realloc (f.__buffer, (f.__bufp - f.__buffer) + 1);
if (*string_ptr == NULL)
*string_ptr = f.__buffer;
(*string_ptr)[f.__bufp - f.__buffer] = '\0';
return done;
}