incubator-nuttx/libs/libc/stream/lib_memoutstream.c

105 lines
3.9 KiB
C

/****************************************************************************
* libs/libc/stream/lib_memoutstream.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 <assert.h>
#include "libc.h"
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: memoutstream_puts
****************************************************************************/
static int memoutstream_puts(FAR struct lib_outstream_s *self,
FAR const void *buf, int len)
{
FAR struct lib_memoutstream_s *stream =
(FAR struct lib_memoutstream_s *)self;
int ncopy;
DEBUGASSERT(self);
/* If this will not overrun the buffer, then write the character to the
* buffer. Note that buflen was pre-decremented when the stream was
* created so it is okay to write past the end of the buflen by one.
*/
ncopy = stream->buflen - self->nput >= len ?
len : stream->buflen - self->nput;
if (ncopy > 0)
{
memcpy(stream->buffer + self->nput, buf, ncopy);
self->nput += ncopy;
stream->buffer[self->nput] = '\0';
}
return ncopy;
}
/****************************************************************************
* Name: memoutstream_putc
****************************************************************************/
static void memoutstream_putc(FAR struct lib_outstream_s *self, int ch)
{
char tmp = ch;
memoutstream_puts(self, &tmp, 1);
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: lib_memoutstream
*
* Description:
* Initializes a stream for use with a fixed-size memory buffer.
*
* Input Parameters:
* outstream - User allocated, uninitialized instance of struct
* lib_memoutstream_s to be initialized.
* bufstart - Address of the beginning of the fixed-size memory buffer
* buflen - Size of the fixed-sized memory buffer in bytes
*
* Returned Value:
* None (outstream initialized).
*
****************************************************************************/
void lib_memoutstream(FAR struct lib_memoutstream_s *outstream,
FAR char *bufstart, int buflen)
{
outstream->common.putc = memoutstream_putc;
outstream->common.puts = memoutstream_puts;
outstream->common.flush = lib_noflush;
outstream->common.nput = 0; /* Will be buffer index */
outstream->buffer = bufstart; /* Start of buffer */
outstream->buflen = buflen - 1; /* Save space for null terminator */
outstream->buffer[0] = '\0'; /* Start with an empty string */
}