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glibc/libio/vasprintf.c
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/* Copyright (C) 1995-2016 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 <malloc.h> | |
#include <string.h> | |
#include "libioP.h" | |
#include "stdio.h" | |
#include <stdio_ext.h> | |
#include "strfile.h" | |
int | |
_IO_vasprintf (char **result_ptr, const char *format, _IO_va_list args) | |
{ | |
/* Initial size of the buffer to be used. Will be doubled each time an | |
overflow occurs. */ | |
const _IO_size_t init_string_size = 100; | |
char *string; | |
_IO_strfile sf; | |
int ret; | |
_IO_size_t needed; | |
_IO_size_t allocated; | |
/* No need to clear the memory here (unlike for open_memstream) since | |
we know we will never seek on the stream. */ | |
string = (char *) malloc (init_string_size); | |
if (string == NULL) | |
return -1; | |
#ifdef _IO_MTSAFE_IO | |
sf._sbf._f._lock = NULL; | |
#endif | |
_IO_no_init (&sf._sbf._f, _IO_USER_LOCK, -1, NULL, NULL); | |
_IO_JUMPS (&sf._sbf) = &_IO_str_jumps; | |
_IO_str_init_static_internal (&sf, string, init_string_size, string); | |
sf._sbf._f._flags &= ~_IO_USER_BUF; | |
sf._s._allocate_buffer = (_IO_alloc_type) malloc; | |
sf._s._free_buffer = (_IO_free_type) free; | |
ret = _IO_vfprintf (&sf._sbf._f, format, args); | |
if (ret < 0) | |
{ | |
free (sf._sbf._f._IO_buf_base); | |
return ret; | |
} | |
/* Only use realloc if the size we need is of the same (binary) | |
order of magnitude then the memory we allocated. */ | |
needed = sf._sbf._f._IO_write_ptr - sf._sbf._f._IO_write_base + 1; | |
allocated = sf._sbf._f._IO_write_end - sf._sbf._f._IO_write_base; | |
if ((allocated >> 1) <= needed) | |
*result_ptr = (char *) realloc (sf._sbf._f._IO_buf_base, needed); | |
else | |
{ | |
*result_ptr = (char *) malloc (needed); | |
if (*result_ptr != NULL) | |
{ | |
memcpy (*result_ptr, sf._sbf._f._IO_buf_base, needed - 1); | |
free (sf._sbf._f._IO_buf_base); | |
} | |
else | |
/* We have no choice, use the buffer we already have. */ | |
*result_ptr = (char *) realloc (sf._sbf._f._IO_buf_base, needed); | |
} | |
if (*result_ptr == NULL) | |
*result_ptr = sf._sbf._f._IO_buf_base; | |
(*result_ptr)[needed - 1] = '\0'; | |
return ret; | |
} | |
ldbl_weak_alias (_IO_vasprintf, vasprintf) |