freebsd-dev/lib/libarchive/archive_string_sprintf.c
Tim Kientzle c47a0d494c Implement a custom print formatter (archive_string_vsprintf)
for libarchive error messages.  Mostly, this
avoids a portability headache related to
copying va_list arguments (some FreeBSD 5
platforms require va_copy; FreeBSD 4 doesn't
support va_copy at all).  It also dramatically reduces the
size of libarchive for embedded applications:
a minimal "untar" program using libarchive can now be
under 64k statically linked (as opposed to ~100k
using library *printf() functions).

MFC after: 14 days
2005-01-16 22:13:51 +00:00

130 lines
3.7 KiB
C

/*-
* Copyright (c) 2003-2004 Tim Kientzle
* All rights reserved.
*
* 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
* in this position and unchanged.
* 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(S) ``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(S) 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.
*/
#include "archive_platform.h"
__FBSDID("$FreeBSD$");
/*
* The use of printf()-family functions can be troublesome
* for space-constrained applications. In addition, correctly
* implementing this function in terms of vsnprintf() requires
* two calls (one to determine the size, another to format the
* result), which in turn requires duplicating the argument list
* using va_copy, which isn't yet universally available.
*
* So, I've implemented a bare minimum of printf()-like capability
* here. This is only used to format error messages, so doesn't
* require any floating-point support or field-width handling.
*/
#include <stdio.h>
#include "archive_string.h"
/*
* Like 'vsprintf', but ensures the target is big enough, resizing if
* necessary.
*/
void
__archive_string_vsprintf(struct archive_string *as, const char *fmt,
va_list ap)
{
char long_flag;
intmax_t s; /* Signed integer temp. */
uintmax_t u; /* Unsigned integer temp. */
const char *p, *p2;
__archive_string_ensure(as, 64);
if (fmt == NULL) {
as->s[0] = 0;
return;
}
long_flag = '\0';
for (p = fmt; *p != '\0'; p++) {
const char *saved_p = p;
if (*p != '%') {
archive_strappend_char(as, *p);
continue;
}
p++;
switch(*p) {
case 'j':
long_flag = 'j';
p++;
break;
case 'l':
long_flag = 'l';
p++;
break;
}
switch (*p) {
case '%':
__archive_strappend_char(as, '%');
break;
case 'c':
s = va_arg(ap, int);
__archive_strappend_char(as, s);
break;
case 'd':
switch(long_flag) {
case 'j': s = va_arg(ap, intmax_t); break;
case 'l': s = va_arg(ap, long); break;
default: s = va_arg(ap, int); break;
}
archive_strappend_int(as, s, 10);
break;
case 's':
p2 = va_arg(ap, char *);
archive_strcat(as, p2);
break;
case 'o': case 'u': case 'x': case 'X':
/* Common handling for unsigned integer formats. */
switch(long_flag) {
case 'j': u = va_arg(ap, uintmax_t); break;
case 'l': u = va_arg(ap, unsigned long); break;
default: u = va_arg(ap, unsigned int); break;
}
/* Format it in the correct base. */
switch (*p) {
case 'o': archive_strappend_int(as, u, 8); break;
case 'u': archive_strappend_int(as, u, 10); break;
default: archive_strappend_int(as, u, 16); break;
}
break;
default:
/* Rewind and print the initial '%' literally. */
p = saved_p;
archive_strappend_char(as, *p);
}
}
}