339 lines
9.6 KiB
C
339 lines
9.6 KiB
C
/****************************************************************************
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* lib/lib_fgets.c
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*
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* Copyright (C) 2007, 2008 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
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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 <stdio.h>
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#include <unistd.h>
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#include <string.h>
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#include <ctype.h>
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#include <debug.h>
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/****************************************************************************
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* Definitions
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****************************************************************************/
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/* In some systems, the underlying serial logic may
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* automatically echo characters back to the console. We
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* will assume that that is not the case here
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*/
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#define CONFIG_FGETS_ECHO 1
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/* Some environments may return CR as end-of-line, others LF, and
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* others both. The logic here assumes either but not both.
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*/
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#undef CONFIG_EOL_IS_CR
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#undef CONFIG_EOL_IS_LF
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#undef CONFIG_EOL_IS_BOTH_CRLF
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#define CONFIG_EOL_IS_EITHER_CRLF 1
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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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* Public Data
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****************************************************************************/
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/****************************************************************************
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* Private Data
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****************************************************************************/
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/* <esc>[K is the VT100 command erases to the end of the line. */
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static const char g_erasetoeol[] = "\033[K";
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Name: _lib_rawgetc
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****************************************************************************/
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static inline int _lib_rawgetc(int fd)
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{
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char buffer;
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if (read(fd, &buffer, 1) < 1)
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{
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/* Return EOF if the end of file (0) or error (-1) occurs */
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return EOF;
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}
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return (int)buffer;
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}
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/****************************************************************************
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* Name: _lib_consoleputc
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****************************************************************************/
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#ifdef CONFIG_FGETS_ECHO
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static inline void _lib_consoleputc(int ch)
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{
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char buffer = ch;
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(void)write(1, &buffer, 1);
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}
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#endif
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/****************************************************************************
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* Name: _lib_consoleputs
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****************************************************************************/
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#ifdef CONFIG_FGETS_ECHO
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static inline void _lib_consoleputs(const char *str)
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{
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(void)write(1, str, strlen(str));
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}
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#endif
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/****************************************************************************
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* Global Functions
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****************************************************************************/
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/****************************************************************************
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* Name: fgets
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*
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* Description:
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* fgets() reads in at most one less than 'buflen' characters
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* from stream and stores them into the buffer pointed to
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* by 'buf'. Reading stops after an EOF or a newline. If a
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* newline is read, it is stored into the buffer. A null
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* terminator is stored after the last character in the
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* buffer.
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*
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* Assumptions:
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* If the stream corresponds to stdin (fd=0) this version
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* will assume that we are reading characters from a
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* VT100 console and that stdout (fd=1) is also available.
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* This will not work well if fd=0 corresponds to a raw
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* byte steam.
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*
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**************************************************************************/
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char *fgets(FAR char *buf, int buflen, FILE *stream)
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{
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#ifdef CONFIG_FGETS_ECHO
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boolean console;
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#endif
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int escape = 0;
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int nch = 0;
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/* Sanity checks */
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if (!stream || !buf || buflen < 1 || stream->fs_filedes < 0)
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{
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return NULL;
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}
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if (buflen < 2)
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{
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*buf = '\0';
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return buf;
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}
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/* Check if the stream is stdin */
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#ifdef CONFIG_FGETS_ECHO
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console = (stream->fs_filedes == 0);
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/* <esc>[K is the VT100 command that erases to the end of the line. */
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if (console)
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{
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_lib_consoleputs(g_erasetoeol);
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}
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#endif
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/* Read characters until we have a full line. On each
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* the loop we must be assured that there are two free bytes
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* in the line buffer: One for the next character and one for
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* the null terminator.
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*/
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for(;;)
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{
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/* Get the next character */
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int ch = _lib_rawgetc(stream->fs_filedes);
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/* Are we processing a VT100 escape sequence */
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if (escape)
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{
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/* Yes, is it an <esc>[, 3 byte sequence */
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if (ch != 0x5b || escape == 2)
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{
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/* We are finished with the escape sequence */
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escape = 0;
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ch = 'a';
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}
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else
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{
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/* The next character is the end of a 3-byte sequence.
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* NOTE: Some of the <esc>[ sequences are longer than
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* 3-bytes, but I have not encountered any in normal use
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* yet and, so, have not provided the decoding logic.
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*/
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escape = 2;
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}
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}
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/* Check for backspace */
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else if (ch == 0x08)
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{
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/* Eliminate that last character in the buffer. */
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if (nch > 0)
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{
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nch--;
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#ifdef CONFIG_FGETS_ECHO
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if (console)
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{
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/* Echo the backspace character on the console */
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_lib_consoleputc(ch);
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_lib_consoleputs(g_erasetoeol);
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}
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#endif
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}
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}
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/* Check for the beginning of a VT100 escape sequence */
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else if (console && ch == 0x1b)
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{
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/* The next character is escaped */
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escape = 1;
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}
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/* Check for end-of-line. This is tricky only in that some
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* environments may return CR as end-of-line, others LF, and
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* others both.
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*/
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#if defined(CONFIG_EOL_IS_LF) || defined(CONFIG_EOL_IS_BOTH_CRLF)
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else if (ch == '\n')
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#elif defined(CONFIG_EOL_IS_CR)
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else if (ch == '\r')
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#elif CONFIG_EOL_IS_EITHER_CRLF
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else if (ch == '\n' || ch == '\r')
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#endif
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{
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/* The newline is stored in the buffer along
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* with the null terminator.
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*/
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buf[nch++] = '\n';
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buf[nch] = '\0';
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#ifdef CONFIG_FGETS_ECHO
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if (console)
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{
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/* Echo the newline to the console */
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_lib_consoleputc('\n');
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}
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#endif
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return buf;
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}
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/* Check for end-of-file */
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else if (ch == EOF)
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{
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/* End of file with no data? */
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if (!nch)
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{
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/* Yes.. return NULL as the end of file mark */
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return NULL;
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}
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else
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{
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/* Terminate the line */
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buf[nch] = '\0';
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return buf;
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}
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}
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/* Otherwise, check if the character is printable and,
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* if so, put the character in the line buffer
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*/
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else if (isprint(ch))
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{
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buf[nch++] = ch;
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#ifdef CONFIG_FGETS_ECHO
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if (console)
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{
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/* Echo the character to the console */
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_lib_consoleputc(ch);
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}
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#endif
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/* Check if there is room for another character
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* and the line's null terminator. If not then
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* we have to end the line now.
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*/
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if (nch + 1 >= buflen)
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{
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buf[nch] = '\0';
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return buf;
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}
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}
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}
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}
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