386 lines
11 KiB
C
386 lines
11 KiB
C
/****************************************************************************
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* lib/stdio/lib_fgets.c
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*
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* Copyright (C) 2007-2008, 2011-2012 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 <stdbool.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 <errno.h>
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#include <debug.h>
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#include <nuttx/ascii.h>
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#include <nuttx/vt100.h>
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#include <apps/readline.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 automatically echo
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* characters back to the console. We will assume that that is not the case
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& here
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*/
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#define CONFIG_READLINE_ECHO 1
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/* Some environments may return CR as end-of-line, others LF, and others
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* 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[] = VT100_CLEAREOL;
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Name: readline_rawgetc
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****************************************************************************/
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static inline int readline_rawgetc(int infd)
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{
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char buffer;
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ssize_t nread;
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/* Loop until we successfully read a character (or until an unexpected
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* error occurs).
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*/
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do
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{
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/* Read one character from the incoming stream */
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nread = read(infd, &buffer, 1);
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/* Return EOF if the end of file (0) or error (-1) occurs. */
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if (nread < 1)
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{
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/* EINTR is not really an error; it simply means that a signal we
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* received while watiing for intput.
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*/
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if (nread == 0 || errno != EINTR)
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{
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return EOF;
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}
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}
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}
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while (nread < 1);
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/* On success, returnt he character that was read */
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return (int)buffer;
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}
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/****************************************************************************
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* Name: readline_consoleputc
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****************************************************************************/
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#ifdef CONFIG_READLINE_ECHO
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static inline void readline_consoleputc(int ch, int outfd)
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{
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char buffer = ch;
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ssize_t nwritten;
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/* Loop until we successfully write a character (or until an unexpected
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* error occurs).
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*/
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do
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{
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/* Write the character to the outgoing stream */
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nwritten = write(outfd, &buffer, 1);
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/* Check for irrecoverable write errors. */
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if (nwritten < 0 && errno != EINTR)
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{
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break;
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}
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}
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while (nwritten < 1);
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}
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#endif
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/****************************************************************************
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* Name: readline_consolewrite
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****************************************************************************/
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#ifdef CONFIG_READLINE_ECHO
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static inline void readline_consolewrite(int outfd, FAR const char *buffer, size_t buflen)
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{
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(void)write(outfd, buffer, buflen);
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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: readline
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*
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* readline() reads in at most one less than 'buflen' characters from
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* 'instream' and stores them into the buffer pointed to by 'buf'.
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* Characters are echoed on 'outstream'. Reading stops after an EOF or a
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* newline. If a newline is read, it is stored into the buffer. A null
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* terminator is stored after the last character in the buffer.
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*
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* This version of realine assumes that we are reading and writing to
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* a VT100 console. This will not work well if 'instream' or 'outstream'
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* corresponds to a raw byte steam.
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*
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* This function is inspired by the GNU readline but is an entirely
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* different creature.
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*
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* Input Parameters:
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* buf - The user allocated buffer to be filled.
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* buflen - the size of the buffer.
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* instream - The stream to read characters from
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* outstream - The stream to each characters to.
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*
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* Returned values:
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* On success, the (positive) number of bytes transferred is returned.
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* A length of zero would indicate an end of file condition. On failure,
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* a negated errno value is returned.
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*
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**************************************************************************/
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ssize_t readline(FAR char *buf, int buflen, FILE *instream, FILE *outstream)
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{
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int infd;
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int outfd;
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int escape;
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int nch;
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/* Sanity checks */
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if (!instream || !outstream || !buf || buflen < 1)
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{
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return -EINVAL;
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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 0;
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}
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/* Extract the file descriptions. This is cheating (and horribly non-
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* standard)
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*/
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infd = instream->fs_filedes;
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outfd = outstream->fs_filedes;
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/* <esc>[K is the VT100 command that erases to the end of the line. */
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#ifdef CONFIG_READLINE_ECHO
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readline_consolewrite(outfd, g_erasetoeol, sizeof(g_erasetoeol));
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#endif
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/* Read characters until we have a full line. On each the loop we must
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* be assured that there are two free bytes in the line buffer: One for
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* the next character and one for the null terminator.
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*/
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escape = 0;
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nch = 0;
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for(;;)
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{
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/* Get the next character */
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int ch = readline_rawgetc(infd);
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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 != ASCII_LBRACKET || 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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*
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* There are several notions of backspace, for an elaborate summary see
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* http://www.ibb.net/~anne/keyboard.html. There is no clean solution.
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* Here both DEL and backspace are treated like backspace here. The
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* Unix/Linux screen terminal by default outputs DEL (0x7f) when the
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* backspace key is pressed.
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*/
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else if (ch == ASCII_BS || ch == ASCII_DEL)
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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_READLINE_ECHO
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/* Echo the backspace character on the console. Always output
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* the backspace character because the VT100 terminal doesn't
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* understand DEL properly.
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*/
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readline_consoleputc(ASCII_BS, outfd);
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readline_consolewrite(outfd, g_erasetoeol, sizeof(g_erasetoeol));
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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 (ch == ASCII_ESC)
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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 with the null
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* 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_READLINE_ECHO
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/* Echo the newline to the console */
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readline_consoleputc('\n', outfd);
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#endif
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return nch;
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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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/* Terminate the line (which might be zero length) */
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buf[nch] = '\0';
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return nch;
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}
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/* Otherwise, check if the character is printable and, if so, put the
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* 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_READLINE_ECHO
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/* Echo the character to the console */
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readline_consoleputc(ch, outfd);
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#endif
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/* Check if there is room for another character and the line's
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* null terminator. If not then 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 nch;
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}
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}
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}
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}
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