123 lines
4.6 KiB
C
123 lines
4.6 KiB
C
/****************************************************************************
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* libc/stdio/lib_snprintf.c
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*
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* Copyright (C) 2007-2009, 2011, 2014 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <sys/types.h>
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#include <stdio.h>
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#include "lib_internal.h"
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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/****************************************************************************
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* Private Type Declarations
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****************************************************************************/
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/****************************************************************************
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* Private Function Prototypes
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****************************************************************************/
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/****************************************************************************
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* Global Constant Data
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****************************************************************************/
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/****************************************************************************
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* Global Variables
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****************************************************************************/
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/****************************************************************************
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* Private Constant Data
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****************************************************************************/
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/****************************************************************************
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* Private Variables
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****************************************************************************/
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/****************************************************************************
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* Global Functions
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****************************************************************************/
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/****************************************************************************
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* sprintf
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****************************************************************************/
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int snprintf(FAR char *buf, size_t size, const char *format, ...)
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{
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union
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{
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struct lib_outstream_s nulloutstream;
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struct lib_memoutstream_s memoutstream;
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} u;
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FAR struct lib_outstream_s *stream;
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va_list ap;
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int n;
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/* "If the value of [size] is zero on a call to snprintf(), nothing shall
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* be written, the number of bytes that would have been written had [size]
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* been sufficiently large excluding the terminating null shall be returned,
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* and [buf] may be a null pointer." -- opengroup.org
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*/
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if (size > 0)
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{
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/* Initialize a memory stream to write to the buffer */
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lib_memoutstream(&u.memoutstream, buf, size);
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stream = &u.memoutstream.public;
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}
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else
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{
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/* Use a null stream to get the size of the buffer */
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lib_nulloutstream(&u.nulloutstream);
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stream = &u.nulloutstream;
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}
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/* Then let lib_vsprintf do the real work */
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va_start(ap, format);
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n = lib_vsprintf(stream, format, ap);
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va_end(ap);
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return n;
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}
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