nuttx/libs/libc/stream/lib_bufferedoutstream.c
Huang Qi b96035885a stdio: Implement simple buffered out stream for vdprintf
Improve performance for raw fd based printf like operation.

Signed-off-by: Huang Qi <huangqi3@xiaomi.com>
2023-03-01 13:08:59 +09:00

121 lines
3.9 KiB
C

/****************************************************************************
* libs/libc/stream/lib_bufferedoutstream.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <unistd.h>
#include <assert.h>
#include <errno.h>
#include <nuttx/fs/fs.h>
#include "libc.h"
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: bufferedoutstream_flush
****************************************************************************/
static int bufferedoutstream_flush(FAR struct lib_outstream_s *this)
{
FAR struct lib_bufferedoutstream_s *rthis =
(FAR struct lib_bufferedoutstream_s *)this;
int ret = OK;
ret = lib_stream_puts(rthis->backend, rthis->buffer,
rthis->pending);
if (ret >= 0)
{
rthis->pending = 0;
}
return ret;
}
/****************************************************************************
* Name: bufferedoutstream_puts
****************************************************************************/
static int bufferedoutstream_puts(FAR struct lib_outstream_s *this,
FAR const void *buf, int len)
{
FAR struct lib_bufferedoutstream_s *rthis =
(FAR struct lib_bufferedoutstream_s *)this;
int ret = len;
if (rthis->pending + len <= CONFIG_STREAM_OUT_BUFFER_SIZE)
{
/* If buffer is enough to save incoming data, cache it */
memcpy(rthis->buffer + rthis->pending, buf, len);
rthis->pending += len;
}
else
{
/* Or, for long data flush buffer and write it directly */
ret = lib_stream_flush(this);
if (ret >= 0)
{
ret = lib_stream_puts(rthis->backend, buf, len);
}
}
return ret;
}
/****************************************************************************
* Name: bufferedoutstream_putc
****************************************************************************/
static void bufferedoutstream_putc(FAR struct lib_outstream_s *this, int ch)
{
char c = ch;
bufferedoutstream_puts(this, &c, 1);
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: lib_bufferedoutstream
****************************************************************************/
void lib_bufferedoutstream(FAR struct lib_bufferedoutstream_s *outstream,
FAR struct lib_outstream_s *backend)
{
outstream->public.putc = bufferedoutstream_putc;
outstream->public.puts = bufferedoutstream_puts;
outstream->public.flush = bufferedoutstream_flush;
outstream->public.nput = 0;
outstream->backend = backend;
outstream->pending = 0;
}