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glibc/libio/vsnprintf.c
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/* Copyright (C) 1994-2016 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 Lesser General Public | |
License as published by the Free Software Foundation; either | |
version 2.1 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 | |
Lesser General Public License for more details. | |
You should have received a copy of the GNU Lesser General Public | |
License along with the GNU C Library; if not, see | |
<http://www.gnu.org/licenses/>. | |
As a special exception, if you link the code in this file with | |
files compiled with a GNU compiler to produce an executable, | |
that does not cause the resulting executable to be covered by | |
the GNU Lesser General Public License. This exception does not | |
however invalidate any other reasons why the executable file | |
might be covered by the GNU Lesser General Public License. | |
This exception applies to code released by its copyright holders | |
in files containing the exception. */ | |
#include "libioP.h" | |
#include "strfile.h" | |
static int _IO_strn_overflow (_IO_FILE *fp, int c) __THROW; | |
static int | |
_IO_strn_overflow (_IO_FILE *fp, int c) | |
{ | |
/* When we come to here this means the user supplied buffer is | |
filled. But since we must return the number of characters which | |
would have been written in total we must provide a buffer for | |
further use. We can do this by writing on and on in the overflow | |
buffer in the _IO_strnfile structure. */ | |
_IO_strnfile *snf = (_IO_strnfile *) fp; | |
if (fp->_IO_buf_base != snf->overflow_buf) | |
{ | |
/* Terminate the string. We know that there is room for at | |
least one more character since we initialized the stream with | |
a size to make this possible. */ | |
*fp->_IO_write_ptr = '\0'; | |
_IO_setb (fp, snf->overflow_buf, | |
snf->overflow_buf + sizeof (snf->overflow_buf), 0); | |
fp->_IO_write_base = snf->overflow_buf; | |
fp->_IO_read_base = snf->overflow_buf; | |
fp->_IO_read_ptr = snf->overflow_buf; | |
fp->_IO_read_end = snf->overflow_buf + sizeof (snf->overflow_buf); | |
} | |
fp->_IO_write_ptr = snf->overflow_buf; | |
fp->_IO_write_end = snf->overflow_buf; | |
/* Since we are not really interested in storing the characters | |
which do not fit in the buffer we simply ignore it. */ | |
return c; | |
} | |
const struct _IO_jump_t _IO_strn_jumps attribute_hidden = | |
{ | |
JUMP_INIT_DUMMY, | |
JUMP_INIT(finish, _IO_str_finish), | |
JUMP_INIT(overflow, _IO_strn_overflow), | |
JUMP_INIT(underflow, _IO_str_underflow), | |
JUMP_INIT(uflow, _IO_default_uflow), | |
JUMP_INIT(pbackfail, _IO_str_pbackfail), | |
JUMP_INIT(xsputn, _IO_default_xsputn), | |
JUMP_INIT(xsgetn, _IO_default_xsgetn), | |
JUMP_INIT(seekoff, _IO_str_seekoff), | |
JUMP_INIT(seekpos, _IO_default_seekpos), | |
JUMP_INIT(setbuf, _IO_default_setbuf), | |
JUMP_INIT(sync, _IO_default_sync), | |
JUMP_INIT(doallocate, _IO_default_doallocate), | |
JUMP_INIT(read, _IO_default_read), | |
JUMP_INIT(write, _IO_default_write), | |
JUMP_INIT(seek, _IO_default_seek), | |
JUMP_INIT(close, _IO_default_close), | |
JUMP_INIT(stat, _IO_default_stat), | |
JUMP_INIT(showmanyc, _IO_default_showmanyc), | |
JUMP_INIT(imbue, _IO_default_imbue) | |
}; | |
int | |
_IO_vsnprintf (char *string, _IO_size_t maxlen, const char *format, | |
_IO_va_list args) | |
{ | |
_IO_strnfile sf; | |
int ret; | |
#ifdef _IO_MTSAFE_IO | |
sf.f._sbf._f._lock = NULL; | |
#endif | |
/* We need to handle the special case where MAXLEN is 0. Use the | |
overflow buffer right from the start. */ | |
if (maxlen == 0) | |
{ | |
string = sf.overflow_buf; | |
maxlen = sizeof (sf.overflow_buf); | |
} | |
_IO_no_init (&sf.f._sbf._f, _IO_USER_LOCK, -1, NULL, NULL); | |
_IO_JUMPS (&sf.f._sbf) = &_IO_strn_jumps; | |
string[0] = '\0'; | |
_IO_str_init_static_internal (&sf.f, string, maxlen - 1, string); | |
ret = _IO_vfprintf (&sf.f._sbf._f, format, args); | |
if (sf.f._sbf._f._IO_buf_base != sf.overflow_buf) | |
*sf.f._sbf._f._IO_write_ptr = '\0'; | |
return ret; | |
} | |
ldbl_weak_alias (_IO_vsnprintf, __vsnprintf) | |
ldbl_weak_alias (_IO_vsnprintf, vsnprintf) |