/****************************************************************************
* apps/system/readline/readline_common.c
*
* Copyright (C) 2007-2008, 2011-2013 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 <nuttx/config.h>
#include <stdbool.h>
#include <string.h>
#include <ctype.h>
#include <errno.h>
#include <assert.h>
#include <debug.h>
#include <nuttx/ascii.h>
#include <nuttx/vt100.h>
#include <apps/readline.h>
#include "readline.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/****************************************************************************
* Private Type Declarations
****************************************************************************/
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
/****************************************************************************
* Public Data
****************************************************************************/
/****************************************************************************
* Private Data
****************************************************************************/
/* <esc>[K is the VT100 command erases to the end of the line. */
static const char g_erasetoeol[] = VT100_CLEAREOL;
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: readline_common
*
* readline() reads in at most one less than 'buflen' characters from
* 'instream' and stores them into the buffer pointed to by 'buf'.
* Characters are echoed on 'outstream'. Reading stops after an EOF or a
* newline. If a newline is read, it is stored into the buffer. A null
* terminator is stored after the last character in the buffer.
*
* This version of realine assumes that we are reading and writing to
* a VT100 console. This will not work well if 'instream' or 'outstream'
* corresponds to a raw byte steam.
*
* This function is inspired by the GNU readline but is an entirely
* different creature.
*
* Input Parameters:
* buf - The user allocated buffer to be filled.
* buflen - the size of the buffer.
* instream - The stream to read characters from
* outstream - The stream to each characters to.
*
* Returned values:
* On success, the (positive) number of bytes transferred is returned.
* EOF is returned to indicate either an end of file condition or a
* failure.
*
**************************************************************************/
ssize_t readline_common(FAR struct rl_common_s *vtbl, FAR char *buf, int buflen)
{
int escape;
int nch;
/* Sanity checks */
DEBUGASSERT(buf && buflen > 0);
if (buflen < 2)
{
*buf = '\0';
return 0;
}
/* <esc>[K is the VT100 command that erases to the end of the line. */
#ifdef CONFIG_READLINE_ECHO
RL_WRITE(vtbl, g_erasetoeol, sizeof(g_erasetoeol));
#endif
/* Read characters until we have a full line. On each the loop we must
* be assured that there are two free bytes in the line buffer: One for
* the next character and one for the null terminator.
*/
escape = 0;
nch = 0;
for (;;)
{
/* Get the next character. readline_rawgetc() returns EOF on any
* errors or at the end of file.
*/
int ch = RL_GETC(vtbl);
/* Check for end-of-file or read error */
if (ch == EOF)
{
/* Did we already received some data? */
if (nch > 0)
{
/* Yes.. Terminate the line (which might be zero length)
* and return the data that was received. The end-of-file
* or error condition will be reported next time.
*/
buf[nch] = '\0';
return nch;
}
return EOF;
}
/* Are we processing a VT100 escape sequence */
else if (escape)
{
/* Yes, is it an <esc>[, 3 byte sequence */
if (ch != ASCII_LBRACKET || escape == 2)
{
/* We are finished with the escape sequence */
escape = 0;
ch = 'a';
}
else
{
/* The next character is the end of a 3-byte sequence.
* NOTE: Some of the <esc>[ sequences are longer than
* 3-bytes, but I have not encountered any in normal use
* yet and, so, have not provided the decoding logic.
*/
escape = 2;
}
}
/* Check for backspace
*
* There are several notions of backspace, for an elaborate summary see
* http://www.ibb.net/~anne/keyboard.html. There is no clean solution.
* Here both DEL and backspace are treated like backspace here. The
* Unix/Linux screen terminal by default outputs DEL (0x7f) when the
* backspace key is pressed.
*/
else if (ch == ASCII_BS || ch == ASCII_DEL)
{
/* Eliminate that last character in the buffer. */
if (nch > 0)
{
nch--;
#ifdef CONFIG_READLINE_ECHO
/* Echo the backspace character on the console. Always output
* the backspace character because the VT100 terminal doesn't
* understand DEL properly.
*/
RL_PUTC(vtbl, ASCII_BS);
RL_WRITE(vtbl, g_erasetoeol, sizeof(g_erasetoeol));
#endif
}
}
/* Check for the beginning of a VT100 escape sequence */
else if (ch == ASCII_ESC)
{
/* The next character is escaped */
escape = 1;
}
/* Check for end-of-line. This is tricky only in that some
* environments may return CR as end-of-line, others LF, and
* others both.
*/
#if defined(CONFIG_EOL_IS_LF) || defined(CONFIG_EOL_IS_BOTH_CRLF)
else if (ch == '\n')
#elif defined(CONFIG_EOL_IS_CR)
else if (ch == '\r')
#elif CONFIG_EOL_IS_EITHER_CRLF
else if (ch == '\n' || ch == '\r')
#endif
{
/* The newline is stored in the buffer along with the null
* terminator.
*/
buf[nch++] = '\n';
buf[nch] = '\0';
#ifdef CONFIG_READLINE_ECHO
/* Echo the newline to the console */
RL_PUTC(vtbl, '\n');
#endif
return nch;
}
/* Otherwise, check if the character is printable and, if so, put the
* character in the line buffer
*/
else if (isprint(ch))
{
buf[nch++] = ch;
#ifdef CONFIG_READLINE_ECHO
/* Echo the character to the console */
RL_PUTC(vtbl, ch);
#endif
/* Check if there is room for another character and the line's
* null terminator. If not then we have to end the line now.
*/
if (nch + 1 >= buflen)
{
buf[nch] = '\0';
return nch;
}
}
}
}
