glibc/libio/memstream.c

143 lines
4.0 KiB
C

/* Copyright (C) 1995-2020 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
<https://www.gnu.org/licenses/>. */
#include "libioP.h"
#include "strfile.h"
#include <stdio.h>
#include <stdlib.h>
struct _IO_FILE_memstream
{
_IO_strfile _sf;
char **bufloc;
size_t *sizeloc;
};
static int _IO_mem_sync (FILE* fp) __THROW;
static void _IO_mem_finish (FILE* fp, int) __THROW;
static const struct _IO_jump_t _IO_mem_jumps libio_vtable =
{
JUMP_INIT_DUMMY,
JUMP_INIT (finish, _IO_mem_finish),
JUMP_INIT (overflow, _IO_str_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_mem_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)
};
/* Open a stream that writes into a malloc'd buffer that is expanded as
necessary. *BUFLOC and *SIZELOC are updated with the buffer's location
and the number of characters written on fflush or fclose. */
FILE *
__open_memstream (char **bufloc, size_t *sizeloc)
{
struct locked_FILE
{
struct _IO_FILE_memstream fp;
#ifdef _IO_MTSAFE_IO
_IO_lock_t lock;
#endif
struct _IO_wide_data wd;
} *new_f;
char *buf;
new_f = (struct locked_FILE *) malloc (sizeof (struct locked_FILE));
if (new_f == NULL)
return NULL;
#ifdef _IO_MTSAFE_IO
new_f->fp._sf._sbf._f._lock = &new_f->lock;
#endif
buf = calloc (1, BUFSIZ);
if (buf == NULL)
{
free (new_f);
return NULL;
}
_IO_init_internal (&new_f->fp._sf._sbf._f, 0);
_IO_JUMPS_FILE_plus (&new_f->fp._sf._sbf) = &_IO_mem_jumps;
_IO_str_init_static_internal (&new_f->fp._sf, buf, BUFSIZ, buf);
new_f->fp._sf._sbf._f._flags &= ~_IO_USER_BUF;
new_f->fp._sf._s._allocate_buffer_unused = (_IO_alloc_type) malloc;
new_f->fp._sf._s._free_buffer_unused = (_IO_free_type) free;
new_f->fp.bufloc = bufloc;
new_f->fp.sizeloc = sizeloc;
/* Disable single thread optimization. BZ 21735. */
new_f->fp._sf._sbf._f._flags2 |= _IO_FLAGS2_NEED_LOCK;
return (FILE *) &new_f->fp._sf._sbf;
}
libc_hidden_def (__open_memstream)
weak_alias (__open_memstream, open_memstream)
static int
_IO_mem_sync (FILE *fp)
{
struct _IO_FILE_memstream *mp = (struct _IO_FILE_memstream *) fp;
if (fp->_IO_write_ptr == fp->_IO_write_end)
{
_IO_str_overflow (fp, '\0');
--fp->_IO_write_ptr;
}
*mp->bufloc = fp->_IO_write_base;
*mp->sizeloc = fp->_IO_write_ptr - fp->_IO_write_base;
return 0;
}
static void
_IO_mem_finish (FILE *fp, int dummy)
{
struct _IO_FILE_memstream *mp = (struct _IO_FILE_memstream *) fp;
*mp->bufloc = (char *) realloc (fp->_IO_write_base,
fp->_IO_write_ptr - fp->_IO_write_base + 1);
if (*mp->bufloc != NULL)
{
(*mp->bufloc)[fp->_IO_write_ptr - fp->_IO_write_base] = '\0';
*mp->sizeloc = fp->_IO_write_ptr - fp->_IO_write_base;
fp->_IO_buf_base = NULL;
}
_IO_str_finish (fp, 0);
}