newlib-cygwin/newlib/libc/stdio/vasnprintf.c

71 lines
1.6 KiB
C

/* Copyright (C) 2007 Eric Blake
* Permission to use, copy, modify, and distribute this software
* is freely granted, provided that this notice is preserved.
*/
/* This code was derived from asprintf.c */
/* doc in vfprintf.c */
#include <_ansi.h>
#include <reent.h>
#include <stdio.h>
#include <stdarg.h>
#include <limits.h>
#include <errno.h>
char *
_DEFUN(_vasnprintf_r, (ptr, buf, lenp, fmt, ap),
struct _reent *ptr _AND
char *buf _AND
size_t *lenp _AND
const char *fmt _AND
va_list ap)
{
int ret;
FILE f;
size_t len = *lenp;
if (buf && len)
{
/* mark an existing buffer, but allow allocation of larger string */
f._flags = __SWR | __SSTR | __SOPT;
}
else
{
/* mark a zero-length reallocatable buffer */
f._flags = __SWR | __SSTR | __SMBF;
len = 0;
buf = NULL;
}
f._bf._base = f._p = (unsigned char *) buf;
/* For now, inherit the 32-bit signed limit of FILE._bf._size.
FIXME - it would be nice to rewrite sys/reent.h to support size_t
for _size. */
if (len > INT_MAX)
{
ptr->_errno = EOVERFLOW;
return NULL;
}
f._bf._size = f._w = len;
f._file = -1; /* No file. */
ret = _svfprintf_r (ptr, &f, fmt, ap);
if (ret < 0)
return NULL;
*lenp = ret;
*f._p = '\0';
return (char *) f._bf._base;
}
#ifndef _REENT_ONLY
char *
_DEFUN(vasnprintf, (buf, lenp, fmt, ap),
char *buf _AND
size_t *lenp _AND
const char *fmt _AND
va_list ap)
{
return _vasnprintf_r (_REENT, buf, lenp, fmt, ap);
}
#endif /* ! _REENT_ONLY */