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/*
* This file is part of the XForms library package.
*
* XForms is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1, or
* (at your option) any later version.
*
* XForms 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with XForms. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef FLVASPRINTF_H
#define FLVASPRINTF_H
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <stdio.h>
#include <stdarg.h>
#include "private/flsnprintf.h"
#if defined ( HAVE_VASPRINTF ) && ! defined ( HAVE_DECL_VASPRINTF )
int
vasprintf( char ** strp,
const char * fmt,
va_list ap );
#endif
/* Macro for allocating a buffer and filling it with a string
* constructed from a format string and an unspecified number
* of arguments. It expects a char pointer first (which will
* be set to the address of the memory allocated for the resulting
* string) and a (const) char pointer with a printf-like format
* string (if the pointer to the format string is NULL memory is
* obtained for the empty string). Of course, the function from
* which the macro is invoked from must be a variadic function,
* called with the appropriate number of types of arguments for
* the format string.
*
* On success the first argument will be set to a buffer long
* enough and containing the intended string. If there wasn't
* enough memory available an attempted is make to at least
* allocate memory for the empty string. If even this fails
* the first macro argument is set to NULL.
*
* Of course it's the responsibility of whatever invoked
* this macro to release the memory allocated here at the
* appropriate time.
*
* The best function to use here would be vasprintf(), which
* exactly does what we need. Older systems may not have it -
* in this case 'HAVE_VASPRINTF isn't defined. Unfortunately,
* we can't use the implementation from the flsnprintf.c file
* since it doesn't get compiled in the way this file is made
* up (and for good reasonsm the way the necessary va_copy()
* function gets defined is broken in more than one way). But
* we can use fli_vsnprintf() from that file, though with some
* difficulties.
*
* For such systems we need a way to not "use up" the va_list
* by initializing it and then passing it to some function
* (that's actually the rationale for using a macro here
* instead of a function!), so we must do the memory allo-
* cation here (if necessary repeatedly) and only call
* fli_vsnprintf().
*
* So the whole existence of this macro is due to backward
* compatibility with old (pre C99) compilers that may have
* a uncommon way of defining a va_list. Messy, isnt' it?
*
* BTW, all locally used variables have names starting with 'l1I_'
* since this is a prefix no sane person would ever use - we try to
* avoid compiler warnings about local variables shadowing already
* defined ones.
*/
#if defined ( HAVE_VASPRINTF )
#define EXPAND_FORMAT_STRING( buf, fmt ) \
do { \
if ( ! fmt || ! *fmt ) \
buf = NULL; \
else if ( ! strchr( fmt, '%' ) ) \
{ \
if ( ( buf = fl_malloc( strlen( fmt ) + 1 ) ) ) \
strcpy( buf, fmt ); \
} \
else \
{ \
va_list l1I_ap; \
\
va_start( l1I_ap, fmt ); \
if ( ! vasprintf( &buf, fmt, l1I_ap ) ) \
buf = NULL; \
va_end( l1I_ap ); \
} \
\
if ( ! buf && ( buf = fl_malloc( 1 ) ) ) \
*buf = '\0'; \
} while ( 0 )
#else
#define EXPAND_FORMAT_STRING( buf, fmt ) \
do { \
if ( ! fmt || ! *fmt ) \
buf = NULL; \
else if ( ! strchr( fmt, '%' ) ) \
{ \
if ( ( buf = fl_malloc( strlen( fmt ) + 1 ) ) ) \
strcpy( buf, fmt ); \
} \
else \
{ \
int l1I_min_needed = strlen( fmt ) + 1; \
int l1I_len = l1I_min_needed; \
char *l1I_p; \
\
for ( l1I_p = strchr( fmt, '%' ); l1I_p; \
l1I_p = strchr( ++l1I_p, '%' ) ) \
l1I_len += 16; \
\
if ( ( buf = fl_malloc( l1I_len ) ) ) \
{ \
while ( 1 ) \
{ \
va_list l1I_ap; \
int l1I_written; \
\
va_start( l1I_ap, fmt ); \
l1I_written = fli_vsnprintf( buf, l1I_len, fmt, l1I_ap ); \
va_end( l1I_ap ); \
\
/* Take care: older libc versions returned a negative \
value if the buffer wasn't large enough space while \
newer ones follow C99 and return the length of the \
string needed (without the trailing '\0') */ \
\
if ( l1I_written > -1 && l1I_len > l1I_written ) \
{ \
if ( l1I_len != l1I_written + 1 ) \
{ \
l1I_p = buf; \
if ( ! ( buf = fl_realloc( l1I_p, \
l1I_written + 1 ) ) ) \
buf = l1I_p; \
} \
break; \
} \
\
l1I_len = l1I_written < 0 ? \
( 2 * l1I_len ) : ( l1I_written + 16 ); \
l1I_p = buf; \
if ( ! ( buf = fl_realloc( l1I_p, l1I_len ) ) ) \
{ \
fl_free( l1I_p ); \
break; \
} \
} \
} \
} \
\
if ( ! buf && ( buf = fl_malloc( 1 ) ) ) \
*buf = '\0'; \
} while ( 0 )
#endif
#endif
/*
* Local variables:
* tab-width: 4
* indent-tabs-mode: nil
* End:
*/
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