px4-firmware/nuttx/lib/stdio/lib_meminstream.c

105 lines
3.9 KiB
C

/****************************************************************************
* lib/stdio/lib_meminstream.c
*
* Copyright (C) 2007-2009, 2011-2012 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <assert.h>
#include "lib_internal.h"
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: meminstream_getc
****************************************************************************/
static int meminstream_getc(FAR struct lib_instream_s *this)
{
FAR struct lib_meminstream_s *mthis = (FAR struct lib_meminstream_s *)this;
int ret;
DEBUGASSERT(this);
/* Get the next character (if any) from the buffer */
if (this->nget < mthis->buflen)
{
ret = mthis->buffer[this->nget];
this->nget++;
}
else
{
ret = EOF;
}
return ret;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: lib_meminstream
*
* Description:
* Initializes a stream for use with a fixed-size memory buffer.
*
* Input parameters:
* meminstream - User allocated, uninitialized instance of struct
* lib_meminstream_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 (meminstream initialized).
*
****************************************************************************/
void lib_meminstream(FAR struct lib_meminstream_s *meminstream,
FAR const char *bufstart, int buflen)
{
meminstream->public.get = meminstream_getc;
meminstream->public.nget = 0; /* Will be buffer index */
meminstream->buffer = bufstart; /* Start of buffer */
meminstream->buflen = buflen; /* Length of the buffer */
}