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/* Output stream referring to a file descriptor.
Copyright (C) 2006-2007, 2015-2016 Free Software Foundation, Inc.
Written by Bruno Haible <bruno@clisp.org>, 2006.
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include <config.h>
/* Specification. */
#include "fd-ostream.h"
#include <assert.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include "error.h"
#include "full-write.h"
#include "xalloc.h"
#include "gettext.h"
#define _(str) gettext (str)
struct fd_ostream : struct ostream
{
fields:
int fd;
char *filename;
char *buffer; /* A buffer, or NULL. */
size_t avail; /* Number of bytes available in the buffer. */
};
#define BUFSIZE 4096
/* Implementation of ostream_t methods. */
static void
fd_ostream::write_mem (fd_ostream_t stream, const void *data, size_t len)
{
if (len > 0)
{
if (stream->buffer != NULL)
{
/* Buffered. */
assert (stream->avail > 0);
#if 0 /* unoptimized */
do
{
size_t n = (len <= stream->avail ? len : stream->avail);
if (n > 0)
{
memcpy (stream->buffer + BUFSIZE - stream->avail, data, n);
data = (char *) data + n;
stream->avail -= n;
len -= n;
}
if (stream->avail == 0)
{
if (full_write (stream->fd, stream->buffer, BUFSIZE) < BUFSIZE)
error (EXIT_FAILURE, errno, _("error writing to %s"),
stream->filename);
stream->avail = BUFSIZE;
}
}
while (len > 0);
#else /* optimized */
if (len < stream->avail)
{
/* Move the data into the buffer. */
memcpy (stream->buffer + BUFSIZE - stream->avail, data, len);
stream->avail -= len;
}
else
{
/* Split the data into:
- a first chunk, which is added to the buffer and output,
- a series of chunks of size BUFSIZE, which can be output
directly, without going through the buffer, and
- a last chunk, which is copied to the buffer. */
size_t n = stream->avail;
memcpy (stream->buffer + BUFSIZE - stream->avail, data, n);
data = (char *) data + n;
len -= n;
if (full_write (stream->fd, stream->buffer, BUFSIZE) < BUFSIZE)
error (EXIT_FAILURE, errno, _("error writing to %s"),
stream->filename);
while (len >= BUFSIZE)
{
if (full_write (stream->fd, data, BUFSIZE) < BUFSIZE)
error (EXIT_FAILURE, errno, _("error writing to %s"),
stream->filename);
data = (char *) data + BUFSIZE;
len -= BUFSIZE;
}
if (len > 0)
memcpy (stream->buffer, data, len);
stream->avail = BUFSIZE - len;
}
#endif
assert (stream->avail > 0);
}
else
{
/* Unbuffered. */
if (full_write (stream->fd, data, len) < len)
error (EXIT_FAILURE, errno, _("error writing to %s"),
stream->filename);
}
}
}
static void
fd_ostream::flush (fd_ostream_t stream)
{
if (stream->buffer != NULL && stream->avail < BUFSIZE)
{
size_t filled = BUFSIZE - stream->avail;
if (full_write (stream->fd, stream->buffer, filled) < filled)
error (EXIT_FAILURE, errno, _("error writing to %s"), stream->filename);
stream->avail = BUFSIZE;
}
}
static void
fd_ostream::free (fd_ostream_t stream)
{
fd_ostream_flush (stream);
free (stream->filename);
free (stream);
}
/* Constructor. */
fd_ostream_t
fd_ostream_create (int fd, const char *filename, bool buffered)
{
fd_ostream_t stream =
(struct fd_ostream_representation *)
xmalloc (sizeof (struct fd_ostream_representation)
+ (buffered ? BUFSIZE : 0));
stream->base.vtable = &fd_ostream_vtable;
stream->fd = fd;
stream->filename = xstrdup (filename);
if (buffered)
{
stream->buffer =
(char *) (void *) stream + sizeof (struct fd_ostream_representation);
stream->avail = BUFSIZE;
}
else
stream->buffer = NULL;
return stream;
}
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