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/****************************************************************************
* libc/stdio/lib_memsostream.c
*
* Copyright (C) 2014 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: memsostream_putc
****************************************************************************/
static void memsostream_putc(FAR struct lib_sostream_s *this, int ch)
{
FAR struct lib_memsostream_s *mthis = (FAR struct lib_memsostream_s *)this;
DEBUGASSERT(this);
/* If this will not overrun the buffer, then write the character to the
* buffer. Not that buflen was pre-decremented when the stream was
* created so it is okay to write past the end of the buflen by one.
*/
if (mthis->offset < mthis->buflen)
{
mthis->buffer[mthis->offset] = ch;
mthis->offset++;
this->nput++;
mthis->buffer[mthis->offset] = '\0';
}
}
/****************************************************************************
* Name: memsostream_seek
****************************************************************************/
static off_t memsostream_seek(FAR struct lib_sostream_s *this, off_t offset,
int whence)
{
FAR struct lib_memsostream_s *mthis = (FAR struct lib_memsostream_s *)this;
off_t newpos;
DEBUGASSERT(this);
switch (whence)
{
case SEEK_CUR:
newpos = (off_t)mthis->offset + offset;
break;
case SEEK_SET:
newpos = offset;
break;
case SEEK_END:
newpos = (off_t)mthis->buflen + offset;
break;
default:
return (off_t)ERROR;
}
/* Make sure that the new position is within range */
if (newpos < 0 || newpos >= (off_t)mthis->buflen)
{
return (off_t)ERROR;
}
/* Return the new position */
mthis->offset = (size_t)newpos;
return newpos;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: lib_memsostream
*
* Description:
* Initializes a stream for use with a fixed-size memory buffer.
*
* Input parameters:
* outstream - User allocated, uninitialized instance of struct
* lib_memsostream_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_memsostream(FAR struct lib_memsostream_s *outstream,
FAR char *bufstart, int buflen)
{
outstream->public.put = memsostream_putc;
#ifdef CONFIG_STDIO_LINEBUFFER
outstream->public.flush = lib_snoflush;
#endif
outstream->public.seek = memsostream_seek;
outstream->public.nput = 0; /* Total number of characters written */
outstream->buffer = bufstart; /* Start of buffer */
outstream->offset = 0; /* Will be the buffer index */
outstream->buflen = buflen - 1; /* Save space for null terminator */
outstream->buffer[0] = '\0'; /* Start with an empty string */
}
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