Add an EMACS-like command line editor that can be used wit NSH

12 files changed, 1232 insertions, 8 deletions

diff --git a/apps/ChangeLog.txt b/apps/ChangeLog.txt
index 146d0943b..a9450b5d3 100644
--- a/apps/ChangeLog.txt
+++ b/apps/ChangeLog.txt
@@ -811,3 +811,10 @@
 	  untested conditions (2014-1-21).
 
 6.34 2014-xx-xx Gregory Nutt <gnutt@nuttx.org>
+
+	* apps/system/cle:  Add a EMACS-like command line editor.  This CLE,
+	  is really more like readline than the NuttX readline is!  Not fully
+	  fully on initial checkout (2014-02-02).
+	* apps/nshlib: Use of the standard tiney readline (about .25KB) is now
+	  an option and can be replaces with the EMACX-like CLE (about 2KB)
+	  (2014-02-02).
diff --git a/apps/include/cle.h b/apps/include/cle.h
new file mode 100644
index 000000000..5cb903212
--- /dev/null
+++ b/apps/include/cle.h
@@ -0,0 +1,87 @@
+/****************************************************************************
+ * apps/include/cle.h
+ *
+ *   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.
+ *
+ ****************************************************************************/
+
+#ifndef __APPS_INCLUDE_CLE_H
+#define __APPS_INCLUDE_CLE_H
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <stdint.h>
+#include <stdio.h>
+
+#ifdef CONFIG_SYSTEM_CLE
+
+/****************************************************************************
+ * Pre-Processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Data
+ ****************************************************************************/
+
+#ifdef __cplusplus
+#define EXTERN extern "C"
+extern "C"
+{
+#else
+#define EXTERN extern
+#endif
+
+/****************************************************************************
+ * Public Function Prototypes
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: cle
+ *
+ * Description:
+ *   EMACS-like command line editor.  This is actually more like readline
+ *   than is the NuttX readline!
+ *
+ ****************************************************************************/
+
+int cle(FAR char *line, uint16_t linelen, FILE *instream, FILE *outstream);
+
+#undef EXTERN
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* CONFIG_SYSTEM_CLE */
+#endif /* __APPS_INCLUDE_CLE_H */
diff --git a/apps/nshlib/Kconfig b/apps/nshlib/Kconfig
index 7fb6a52b3..8a9d1e900 100644
--- a/apps/nshlib/Kconfig
+++ b/apps/nshlib/Kconfig
@@ -6,13 +6,37 @@
 config NSH_LIBRARY
 	bool "NSH Library"
 	default n
-	select SYSTEM_READLINE
 	---help---
-		Build the NSH support library.  This is used, for example, by examples/nsh
-		in order to implement the full NuttShell (NSH).
+		Build the NSH support library.  This is used, for example, by
+		examples/nsh in order to implement the full NuttShell (NSH).
 
 if NSH_LIBRARY
 
+choice
+	prompt "Command Line Editor"
+	default NSH_READLINE
+
+config NSH_READLINE
+	bool "Minimal readline()"
+	select SYSTEM_READLINE
+	---help---
+		Selects the minimal implementation of readline().  This minimal
+		implementation provides on backspace for command line editing.
+
+config NSH_CLE
+	bool "Command Line Editor"
+	select SYSTEM_CLE
+	---help---
+		Selects the more extensive, EMACS-like command line editor.
+		Select this option only if (1) you don't mind a modest increase
+		in the FLASH footprint, and (2) you work with a terminal that
+		support VT100 editing commands.
+
+		Selecting this option will add probably 1.5-2KB to the FLASH
+		footprint.
+
+endchoice
+
 config NSH_BUILTIN_APPS
 	bool "Enable built-in applications"
 	default n
diff --git a/apps/nshlib/nsh_session.c b/apps/nshlib/nsh_session.c
index 2272b1e30..de6710bfe 100644
--- a/apps/nshlib/nsh_session.c
+++ b/apps/nshlib/nsh_session.c
@@ -1,7 +1,7 @@
 /****************************************************************************
  * apps/nshlib/nsh_session.c
  *
- *   Copyright (C) 2007-2009, 2011-2013 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2007-2009, 2011-2014 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -42,7 +42,11 @@
 #include <stdio.h>
 #include <stdlib.h>
 
-#include <apps/readline.h>
+#ifdef CONFIG_NSH_CLE
+#  include <apps/cle.h>
+#else
+#  include <apps/readline.h>
+#endif
 
 #include "nsh.h"
 #include "nsh_console.h"
@@ -133,8 +137,13 @@ int nsh_session(FAR struct console_stdio_s *pstate)
        * or any read failure.
        */
 
+#ifdef CONFIG_NSH_CLE
+      ret = cle(pstate->cn_line, CONFIG_NSH_LINELEN,
+                INSTREAM(pstate), OUTSTREAM(pstate));
+#else
       ret = readline(pstate->cn_line, CONFIG_NSH_LINELEN,
                      INSTREAM(pstate), OUTSTREAM(pstate));
+#endif
       if (ret != EOF)
         {
           /* Parse process the command */
diff --git a/apps/nshlib/nsh_stdsession.c b/apps/nshlib/nsh_stdsession.c
index 11fae7db7..07def5b3b 100644
--- a/apps/nshlib/nsh_stdsession.c
+++ b/apps/nshlib/nsh_stdsession.c
@@ -1,7 +1,7 @@
 /****************************************************************************
  * apps/nshlib/nsh_stdsession.c
  *
- *   Copyright (C) 2013 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2013-2014 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -42,7 +42,11 @@
 #include <stdio.h>
 #include <stdlib.h>
 
-#include <apps/readline.h>
+#ifdef CONFIG_NSH_CLE
+#  include <apps/cle.h>
+#else
+#  include <apps/readline.h>
+#endif
 
 #include "nsh.h"
 #include "nsh_console.h"
@@ -124,7 +128,12 @@ int nsh_session(FAR struct console_stdio_s *pstate)
        * or any read failure.
        */
 
+#ifdef CONFIG_NSH_CLE
+      ret = cle(pstate->cn_line, CONFIG_NSH_LINELEN,
+                stdin, stdout);
+#else
       ret = std_readline(pstate->cn_line, CONFIG_NSH_LINELEN);
+#endif
       if (ret != EOF)
         {
           /* Parse process the command */
diff --git a/apps/system/Kconfig b/apps/system/Kconfig
index 15836f1f2..e7d00bc2e 100644
--- a/apps/system/Kconfig
+++ b/apps/system/Kconfig
@@ -63,6 +63,10 @@ menu "USB Monitor"
 source "$APPSDIR/system/usbmonitor/Kconfig"
 endmenu
 
+menu "EMACS-like Command Line Editor"
+source "$APPSDIR/system/cle/Kconfig"
+endmenu
+
 menu "VI Work-Alike Editor"
 source "$APPSDIR/system/vi/Kconfig"
 endmenu
diff --git a/apps/system/Make.defs b/apps/system/Make.defs
index c0af2ec15..33a40c0aa 100644
--- a/apps/system/Make.defs
+++ b/apps/system/Make.defs
@@ -102,6 +102,10 @@ ifeq ($(CONFIG_SYSTEM_USBMSC),y)
 CONFIGURED_APPS += system/usbmsc
 endif
 
+ifeq ($(CONFIG_SYSTEM_CLE),y)
+CONFIGURED_APPS += system/cle
+endif
+
 ifeq ($(CONFIG_SYSTEM_VI),y)
 CONFIGURED_APPS += system/vi
 endif
diff --git a/apps/system/Makefile b/apps/system/Makefile
index 08a67d22d..149c7a4ab 100644
--- a/apps/system/Makefile
+++ b/apps/system/Makefile
@@ -37,7 +37,7 @@
 
 # Sub-directories containing system task
 
-SUBDIRS  = cdcacm composite flash_eraseall free i2c inifile install
+SUBDIRS  = cdcacm cle composite flash_eraseall free i2c inifile install
 SUBDIRS += nxplayer poweroff ramtest ramtron readline sdcard stackmonitor
 SUBDIRS += sysinfo usbmonitor usbmsc vi zmodem
 
diff --git a/apps/system/cle/.gitignore b/apps/system/cle/.gitignore
new file mode 100644
index 000000000..83bd7b811
--- /dev/null
+++ b/apps/system/cle/.gitignore
@@ -0,0 +1,11 @@
+/Make.dep
+/.depend
+/.built
+/*.asm
+/*.rel
+/*.lst
+/*.sym
+/*.adb
+/*.lib
+/*.src
+/*.obj
diff --git a/apps/system/cle/Kconfig b/apps/system/cle/Kconfig
new file mode 100644
index 000000000..d846a0cf8
--- /dev/null
+++ b/apps/system/cle/Kconfig
@@ -0,0 +1,37 @@
+#
+# For a description of the syntax of this configuration file,
+# see misc/tools/kconfig-language.txt.
+#
+
+config SYSTEM_CLE
+	bool "Tiny VI work-alike command line editor"
+	default n
+	---help---
+		Enable support for NuttX tiny EMACS-like command line editor.
+
+		Omitted features:
+			- No keypad cursor control support
+			- No word oriented operations.
+
+		Assumptions and Limitations:
+			- A VT100 host terminal is assumed.
+			- A fixed width character set (like Courier) is assumed
+
+		Memory Usage:  Looks like 1.5-2KB
+
+if SYSTEM_CLE
+
+config SYSTEM_CLE_DEBUGLEVEL
+	int "Debug level"
+	default 0
+	range 0 2
+	---help---
+		0=Debug off; 1=Print errors on console; 2=Print debug information
+		on the console.
+
+		Debug output is generated with syslog.  The editor works on
+		/dev/console.  In order to get both a usable display and also
+		readable debug output, syslog'ing should sent to some device other
+		than /dev/console (which is the default).
+
+endif # SYSTEM_CLE
diff --git a/apps/system/cle/Makefile b/apps/system/cle/Makefile
new file mode 100644
index 000000000..cce4bb109
--- /dev/null
+++ b/apps/system/cle/Makefile
@@ -0,0 +1,103 @@
+############################################################################
+# apps/system/cle/Makefile
+#
+#   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.
+#
+############################################################################
+
+-include $(TOPDIR)/.config
+-include $(TOPDIR)/Make.defs
+include $(APPDIR)/Make.defs
+
+ifeq ($(WINTOOL),y)
+INCDIROPT	= -w
+endif
+
+# EMACS-like Command Line Editor (CLE)
+
+ASRCS		=
+CSRCS		= cle.c
+
+AOBJS		= $(ASRCS:.S=$(OBJEXT))
+COBJS		= $(CSRCS:.c=$(OBJEXT))
+
+SRCS		= $(ASRCS) $(CSRCS)
+OBJS		= $(AOBJS) $(COBJS)
+
+ifeq ($(CONFIG_WINDOWS_NATIVE),y)
+  BIN		= ..\..\libapps$(LIBEXT)
+else
+ifeq ($(WINTOOL),y)
+  BIN		= ..\\..\\libapps$(LIBEXT)
+else
+  BIN		= ../../libapps$(LIBEXT)
+endif
+endif
+
+ROOTDEPPATH	= --dep-path .
+
+# Common build
+
+VPATH		= 
+
+all:	.built
+.PHONY: context depend clean distclean
+
+$(AOBJS): %$(OBJEXT): %.S
+	$(call ASSEMBLE, $<, $@)
+
+$(COBJS): %$(OBJEXT): %.c
+	$(call COMPILE, $<, $@)
+
+.built: $(OBJS)
+	$(call ARCHIVE, $(BIN), $(OBJS))
+	$(Q) touch .built
+
+context:
+
+# Create dependencies
+
+.depend: Makefile $(SRCS)
+	$(Q) $(MKDEP) $(ROOTDEPPATH) "$(CC)" -- $(CFLAGS) -- $(SRCS) >Make.dep
+	$(Q) touch $@
+
+depend: .depend
+
+clean:
+	$(call DELFILE, .built)
+	$(call CLEAN)
+
+distclean: clean
+	$(call DELFILE, Make.dep)
+	$(call DELFILE, .depend)
+
+-include Make.dep
+
diff --git a/apps/system/cle/cle.c b/apps/system/cle/cle.c
new file mode 100644
index 000000000..6ed8d12aa
--- /dev/null
+++ b/apps/system/cle/cle.c
@@ -0,0 +1,929 @@
+/****************************************************************************
+ * apps/system/cle/cle.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 <nuttx/config.h>
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <string.h>
+#include <ctype.h>
+#include <syslog.h>
+#include <errno.h>
+#include <debug.h>
+
+#include <nuttx/ascii.h>
+#include <nuttx/vt100.h>
+
+#include <apps/cle.h>
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/* Some environments may return CR as end-of-line, others LF, and others
+ * both.  If not specified, the logic here assumes either (but not both) as
+ * the default.
+ */
+
+#if defined(CONFIG_EOL_IS_CR)
+#  undef  CONFIG_EOL_IS_LF
+#  undef  CONFIG_EOL_IS_BOTH_CRLF
+#  undef  CONFIG_EOL_IS_EITHER_CRLF
+#elif defined(CONFIG_EOL_IS_LF)
+#  undef  CONFIG_EOL_IS_CR
+#  undef  CONFIG_EOL_IS_BOTH_CRLF
+#  undef  CONFIG_EOL_IS_EITHER_CRLF
+#elif defined(CONFIG_EOL_IS_BOTH_CRLF)
+#  undef  CONFIG_EOL_IS_CR
+#  undef  CONFIG_EOL_IS_LF
+#  undef  CONFIG_EOL_IS_EITHER_CRLF
+#elif defined(CONFIG_EOL_IS_EITHER_CRLF)
+#  undef  CONFIG_EOL_IS_CR
+#  undef  CONFIG_EOL_IS_LF
+#  undef  CONFIG_EOL_IS_BOTH_CRLF
+#else
+#  undef  CONFIG_EOL_IS_CR
+#  undef  CONFIG_EOL_IS_LF
+#  undef  CONFIG_EOL_IS_BOTH_CRLF
+#  define CONFIG_EOL_IS_EITHER_CRLF 1
+#endif
+
+/* Control characters */
+
+#undef  CTRL
+#define CTRL(a)         ((a) & 0x1f)
+
+#define CLE_BEL(cle)    cle_putch(cle,CTRL('G'))
+
+/* Sizes of things */
+
+#define TABSIZE         8    /* A TAB is eight characters */
+#define TABMASK         7    /* Mask for TAB alignment */
+#define NEXT_TAB(p)     (((p) + TABSIZE) & ~TABMASK)
+
+/* Debug */
+
+#ifndef CONFIG_SYSEM_CLE_DEBUGLEVEL
+#  define CONFIG_SYSEM_CLE_DEBUGLEVEL 0
+#endif
+
+#ifdef CONFIG_CPP_HAVE_VARARGS
+#  if CONFIG_SYSEM_CLE_DEBUGLEVEL > 0
+#    define vidbg(format, arg...) \
+       syslog(EXTRA_FMT format EXTRA_ARG, ##arg)
+#    define vvidbg(format, ap) \
+       vsyslog(format, ap)
+#  else
+#    define vidbg(x...)
+#    define vvidbg(x...)
+#  endif
+
+#  if CONFIG_SYSEM_CLE_DEBUGLEVEL > 1
+#    define vivdbg(format, arg...) \
+       syslog(EXTRA_FMT format EXTRA_ARG, ##arg)
+#  else
+#    define vivdbg(x...)
+#  endif
+#else
+#  if CONFIG_SYSEM_CLE_DEBUGLEVEL > 0
+#    define vidbg  syslog
+#    define vvidbg vsyslog
+#  else
+#    define vidbg  (void)
+#    define vvidbg (void)
+#  endif
+
+#  if CONFIG_SYSEM_CLE_DEBUGLEVEL > 1
+#    define vivdbg syslog
+#  else
+#    define vivdbg (void)
+#  endif
+#endif
+
+/****************************************************************************
+ * Private Types
+ ****************************************************************************/
+/* VI Key Bindings */
+
+enum cle_key_e
+{
+  KEY_BEGINLINE   = CTRL('A'),  /* Move cursor to start of current line */
+  KEY_LEFT        = CTRL('B'),  /* Move left one character */
+  KEY_DEL         = CTRL('D'),  /* Delete a single character at the cursor position*/
+  KEY_ENDLINE     = CTRL('E'),  /* Move cursor to end of current line */
+  KEY_RIGHT       = CTRL('F'),  /* Move right one character */
+  KEY_DELLEFT     = CTRL('H'),  /* Delete character, left (backspace)  */
+  KEY_DELEOL      = CTRL('K'),  /* Delete to the end of the line */
+  KEY_DELLINE     = CTRL('U'),  /* Delete the entire line */
+  KEY_QUOTE       = '\\',       /* The next character is quote (use literal value) */
+};
+
+/* This structure describes the overall state of the editor */
+
+struct cle_s
+{
+  uint16_t curpos;          /* Current cursor position */
+  uint16_t cursave;         /* Saved cursor position */
+  uint16_t row;             /* This is the row that we are editing iun */
+  uint16_t coloffs;         /* Left cursor offset */
+  uint16_t linelen;         /* Size of the line buffer */
+  uint16_t nchars;          /* Size of data in the line buffer */
+  int infd;                 /* Input file descriptor */
+  int outfd;                /* Output file descriptor */
+  FAR char *line;           /* Line buffer */
+};
+
+/****************************************************************************
+ * Private Function Prototypes
+ ****************************************************************************/
+
+/* Low-level display and data entry functions */
+
+static void     cle_write(FAR struct cle_s *cle, FAR const char *buffer,
+                  uint16_t buflen);
+static void     cle_putch(FAR struct cle_s *cle, char ch);
+static int      cle_getch(FAR struct cle_s *cle);
+static void     cle_cursoron(FAR struct cle_s *cle);
+static void     cle_cursoroff(FAR struct cle_s *cle);
+static void     cle_setcursor(FAR struct cle_s *cle, uint16_t column);
+static int      cle_getcursor(FAR struct cle_s *cle, uint16_t *prow,
+                  uint16_t *pcolumn);
+static void     cle_clrtoeol(FAR struct cle_s *cle);
+
+/* Editor function */
+
+static bool     cle_opentext(FAR struct cle_s *cle, uint16_t pos,
+                  uint16_t increment);
+static void     cle_closetext(FAR struct cle_s *cle, uint16_t pos, uint16_t size);
+static void     cle_showtext(FAR struct cle_s *cle);
+static void     cle_insertch(FAR struct cle_s *cle, char ch);
+static int      cle_editloop(FAR struct cle_s *cle);
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/* VT100 escape sequences */
+
+static const char g_cursoron[]      = VT100_CURSORON;
+static const char g_cursoroff[]     = VT100_CURSOROFF;
+static const char g_getcursor[]     = VT100_GETCURSOR;
+static const char g_erasetoeol[]    = VT100_CLEAREOL;
+static const char g_attriboff[]     = VT100_MODESOFF;
+static const char g_fmtcursorpos[]  = VT100_FMT_CURSORPOS;
+
+/* Error format strings */
+
+static const char g_fmtnotvalid[]   = "Command not valid";
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Low-level display and data entry functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: cle_write
+ *
+ * Description:
+ *   Write a sequence of bytes to the console device (stdout, fd = 1).
+ *
+ ****************************************************************************/
+
+static void cle_write(FAR struct cle_s *cle, FAR const char *buffer,
+                     uint16_t buflen)
+{
+  ssize_t nwritten;
+  uint16_t  nremaining = buflen;
+
+  //vivdbg("buffer=%p buflen=%d\n", buffer, (int)buflen);
+
+  /* Loop until all bytes have been successuflly written (or until a
+   * un-recoverable error is encountered)
+   */
+
+  do
+    {
+      /* Take the next gulp */
+
+      nwritten = write(cle->outfd, buffer, buflen);
+
+      /* Handle write errors.  write() should neve return 0. */
+
+      if (nwritten <= 0)
+        {
+          /* EINTR is not really an error; it simply means that a signal was
+           * received while waiting for write.
+           */
+
+          int errcode = errno;
+          if (nwritten == 0 || errcode != EINTR)
+            {
+              vidbg("ERROR: write to stdout failed: %d\n", errcode);
+              return;
+            }
+        }
+
+      /* Decrement the count of bytes remaining to be sent (to handle the
+       * case of a partial write)
+       */
+
+      else
+        {
+          nremaining -= nwritten;
+        }
+    }
+  while (nremaining > 0);
+}
+
+/****************************************************************************
+ * Name: cle_putch
+ *
+ * Description:
+ *   Write a single character to the console device.
+ *
+ ****************************************************************************/
+
+static void cle_putch(FAR struct cle_s *cle, char ch)
+{
+  cle_write(cle, &ch, 1);
+}
+
+/****************************************************************************
+ * Name: cle_getch
+ *
+ * Description:
+ *   Get a single character from the console device (stdin, fd = 0).
+ *
+ ****************************************************************************/
+
+static int cle_getch(FAR struct cle_s *cle)
+{
+  char buffer;
+  ssize_t nread;
+
+  /* Loop until we successfully read a character (or until an unexpected
+   * error occurs).
+   */
+
+  do
+    {
+      /* Read one character from the incoming stream */
+
+      nread = read(cle->infd, &buffer, 1);
+
+      /* Check for error or end-of-file. */
+
+      if (nread <= 0)
+        {
+          /* EINTR is not really an error; it simply means that a signal we
+           * received while waiting for input.
+           */
+
+          int errcode = errno;
+          if (nread == 0 || errcode != EINTR)
+            {
+              vidbg("ERROR: read from stdin failed: %d\n", errcode);
+              return -EIO;
+            }
+        }
+    }
+  while (nread < 1);
+
+  /* On success, return the character that was read */
+
+  vivdbg("Returning: %c[%02x]\n", isprint(buffer) ? buffer : '.', buffer);
+  return buffer;
+}
+
+/****************************************************************************
+ * Name: cle_cursoron
+ *
+ * Description:
+ *   Turn on the cursor
+ *
+ ****************************************************************************/
+
+static void cle_cursoron(FAR struct cle_s *cle)
+{
+  /* Send the VT100 CURSORON command */
+
+  cle_write(cle, g_cursoron, sizeof(g_cursoron));
+}
+
+/****************************************************************************
+ * Name: cle_cursoroff
+ *
+ * Description:
+ *   Turn off the cursor
+ *
+ ****************************************************************************/
+
+static void cle_cursoroff(FAR struct cle_s *cle)
+{
+  /* Send the VT100 CURSOROFF command */
+
+  cle_write(cle, g_cursoroff, sizeof(g_cursoroff));
+}
+
+/****************************************************************************
+ * Name: cle_setcursor
+ *
+ * Description:
+ *   Move the current cursor position to position (row,col)
+ *
+ ****************************************************************************/
+
+static void cle_setcursor(FAR struct cle_s *cle, uint16_t column)
+{
+  char buffer[16];
+  int len;
+
+  vivdbg("row=%d column=%d\n", row, column);
+
+  /* Format the cursor position command.  The origin is (1,1). */
+
+  len = snprintf(buffer, 16, g_fmtcursorpos, cle->row, column + cle->coloffs);
+
+  /* Send the VT100 CURSORPOS command */
+
+  cle_write(cle, buffer, len);
+}
+
+/****************************************************************************
+ * Name: cle_getcursor
+ *
+ * Description:
+ *   Get the current cursor position.
+ *
+ ****************************************************************************/
+
+static int cle_getcursor(FAR struct cle_s *cle, FAR uint16_t *prow,
+                        FAR uint16_t *pcolumn)
+{
+  uint32_t row;
+  uint32_t column;
+  int nbad;
+  int ch;
+
+  /* Send the VT100 GETCURSOR command */
+
+  cle_write(cle, g_getcursor, sizeof(g_getcursor));
+
+  /* We expect to get ESCv;hR where v is the row and h is the column */
+
+  nbad = 0;
+  for (;;)
+    {
+      /* Get the next character from the input */
+
+      ch = cle_getch(cle);
+      if (ch == ASCII_ESC)
+        {
+          break;
+        }
+      else if (ch < 0)
+        {
+          return -EIO;
+        }
+      else if (++nbad > 3)
+        {
+          /* We are probably talking to a non-VT100 terminal! */
+
+          return -EINVAL;
+        }
+    }
+
+  /* Now we expect to see a numeric value terminated with ';' */
+
+  row = 0;
+  for (;;)
+    {
+      /* Get the next character from the input */
+
+      ch = cle_getch(cle);
+      if (isdigit(ch))
+        {
+          row = 10*row + (ch - '0');
+        }
+      else if (ch == ';')
+        {
+          break;
+        }
+      else if (ch < 0)
+        {
+          return -EIO;
+        }
+      else
+        {
+          return -EINVAL;
+        }
+    }
+
+  /* Now we expect to see another numeric value terminated with 'R' */
+
+  column = 0;
+  for (;;)
+    {
+      /* Get the next character from the input */
+
+      ch = cle_getch(cle);
+      if (isdigit(ch))
+        {
+          column = 10*column + (ch - '0');
+        }
+      else if (ch == 'R')
+        {
+          break;
+        }
+      else if (ch < 0)
+        {
+          return -EIO;
+        }
+      else
+        {
+          return -EINVAL;
+        }
+    }
+
+  vivdbg("row=%ld column=%ld\n", row, column);
+
+  /* Make sure that the values are within range */
+
+  if (row <= UINT16_MAX && column <= UINT16_MAX)
+    {
+      *prow    = row;
+      *pcolumn = column;
+      return OK;
+    }
+
+  return -ERANGE;
+}
+
+/****************************************************************************
+ * Name: cle_clrtoeol
+ *
+ * Description:
+ *   Clear the display from the current cursor position to the end of the
+ *   current line.
+ *
+ ****************************************************************************/
+
+static void cle_clrtoeol(FAR struct cle_s *cle)
+{
+  /* Send the VT100 ERASETOEOL command */
+
+  cle_write(cle, g_erasetoeol, sizeof(g_erasetoeol));
+}
+
+/****************************************************************************
+ * Name: cle_opentext
+ *
+ * Description:
+ *   Make space for new text of size 'increment' at the specified cursor
+ *   position.
+ *
+ ****************************************************************************/
+
+static bool cle_opentext(FAR struct cle_s *cle, uint16_t pos, uint16_t increment)
+{
+  int i;
+
+  vivdbg("pos=%ld increment=%ld\n", (long)pos, (long)increment);
+
+  /* Check if there is space in the line buffer to open up a region the size
+   * of 'increment'
+   */
+
+  if (cle->nchars + increment > cle->linelen)
+    {
+      return false;
+    }
+
+  /* Move text to make space for new text of size 'increment' at the current
+   * cursor position
+   */
+
+  for (i = cle->nchars - 1; i >= pos; i--)
+    {
+      cle->line[i + increment] = cle->line[i];
+    }
+
+  /* Adjust end of file position */
+
+  cle->nchars += increment;
+  return true;
+}
+
+/****************************************************************************
+ * Name: cle_closetext
+ *
+ * Description:
+ *   Delete a region in the line buffer by copying the end of the line buffer
+ *   over the deleted region and adjusting the size of the region.
+ *
+ ****************************************************************************/
+
+static void cle_closetext(FAR struct cle_s *cle, uint16_t pos, uint16_t size)
+{
+  int i;
+
+  vivdbg("pos=%ld size=%ld\n", (long)pos, (long)size);
+
+  /* Close up the gap to remove 'size' characters at 'pos' */
+
+  for (i = pos + size; i < cle->nchars; i++)
+    {
+      cle->line[i - size] = cle->line[i];
+    }
+
+  /* Adjust sizes and positions */
+
+  cle->nchars -= size;
+
+  /* Check if the cursor position is beyond the deleted region */
+
+  if (cle->curpos > pos + size)
+    {
+      /* Yes... just subtract the size of the deleted region */
+
+      cle->curpos -= size;
+    }
+
+  /* What if the position is within the deleted region?  Set it to the
+   * beginning of the deleted region.
+   */
+
+  else if (cle->curpos > pos)
+    {
+      cle->curpos = pos;
+    }
+}
+
+/****************************************************************************
+ * Name: cle_showtext
+ *
+ * Description:
+ *   Update the display based on the last operation.  This function is
+ *   called at the beginning of the processing loop in Command and Insert
+ *   modes (and also in the continuous replace mode).
+ *
+ ****************************************************************************/
+
+static void cle_showtext(FAR struct cle_s *cle)
+{
+  uint16_t column;
+  uint16_t tabcol;
+
+  /* Turn off the cursor during the update. */
+
+  cle_cursoroff(cle);
+
+  /* Set the cursor position to the beginning of this row */
+
+  cle_setcursor(cle, 0);
+  cle_clrtoeol(cle);
+
+  /* Loop for each column */
+
+  for (column = 0; column < cle->nchars && column < cle->linelen; column++)
+    {
+      /* Perform TAB expansion */
+
+      if (cle->line[column] == '\t')
+        {
+          tabcol = NEXT_TAB(column);
+          if (tabcol < cle->linelen)
+            {
+              for (; column < tabcol; column++)
+                {
+                  cle_putch(cle, ' ');
+                }
+            }
+          else
+            {
+              /* Break out of the loop... there is nothing left on the
+               * line but whitespace.
+               */
+
+              break;
+            }
+        }
+
+      /* Add the normal character to the display */
+
+      else
+        {
+          cle_putch(cle, cle->line[column]);
+          column++;
+        }
+    }
+
+  /* Turn the cursor back on */
+
+  cle_cursoron(cle);
+}
+
+/****************************************************************************
+ * Name: cle_insertch
+ *
+ * Description:
+ *   Insert one character into the line buffer
+ *
+ ****************************************************************************/
+
+static void cle_insertch(FAR struct cle_s *cle, char ch)
+{
+  vivdbg("curpos=%ld ch=%c[%02x]\n", cle->curpos, isprint(ch) ? ch : '.', ch);
+
+  /* Make space in the buffer for the new character */
+
+  if (cle_opentext(cle, cle->curpos, 1))
+    {
+      /* Add the new character to the buffer */
+
+      cle->line[cle->curpos++] = ch;
+    }
+}
+
+/****************************************************************************
+ * Name: cle_editloop
+ *
+ * Description:
+ *   Command line editor loop
+ *
+ ****************************************************************************/
+
+static int cle_editloop(FAR struct cle_s *cle)
+{
+  /* Loop while we are in command mode */
+
+  for (;;)
+    {
+      int ch;
+
+      /* Make sure that the display reflects the current state */
+
+      cle_showtext(cle);
+      cle_setcursor(cle, cle->curpos);
+
+      /* Get the next character from the input */
+
+      ch = cle_getch(cle);
+      if (ch < 0)
+        {
+          return -EIO;
+        }
+
+      /* Then handle the character. */
+
+      switch (ch)
+        {
+        case KEY_BEGINLINE: /* Move cursor to start of current line */
+          {
+            cle->curpos = 0;
+          }
+          break;
+
+        case KEY_LEFT: /* Move the cursor left 1 character */
+          {
+            if (cle->curpos > 0)
+              {
+                cle->curpos--;
+              }
+            else
+              {
+                CLE_BEL(cle);
+              }
+          }
+          break;
+
+        case KEY_DEL: /* Delete 1 character at the cursor */
+        case ASCII_DEL:
+          {
+            if (cle->curpos < cle->nchars)
+              {
+                cle_closetext(cle, cle->curpos, 1);
+              }
+            else
+              {
+                CLE_BEL(cle);
+              }
+          }
+          break;
+
+        case KEY_ENDLINE: /* Move cursor to end of current line */
+          {
+            if (cle->nchars > 0)
+              {
+                cle->curpos = cle->nchars - 1;
+              }
+            else
+              {
+                CLE_BEL(cle);
+              }
+          }
+          break;
+
+        case KEY_RIGHT: /* Move the cursor right one character */
+          {
+            if (cle->curpos < cle->nchars)
+              {
+                cle->curpos++;
+              }
+            else
+              {
+                CLE_BEL(cle);
+              }
+          }
+          break;
+
+        case KEY_DELLEFT: /* Delete 1 character before the cursor */
+        //case ASCII_BS:
+          {
+            if (cle->curpos > 0)
+              {
+                cle_closetext(cle, --cle->curpos, 1);
+              }
+            else
+              {
+                CLE_BEL(cle);
+              }
+          }
+          break;
+
+        case KEY_DELEOL:  /* Delete to the end of the line */
+          {
+            cle->nchars = (cle->nchars > 0 ? cle->curpos + 1 : 0);
+          }
+          break;
+
+        case KEY_DELLINE:  /* Delete to the end of the line */
+          {
+            cle->nchars = 0;
+            cle->curpos = 0;
+          }
+          break;
+
+        case KEY_QUOTE: /* Quoted character follows */
+          {
+            ch = cle_getch(cle);
+            if (ch < 0)
+              {
+                return -EIO;
+              }
+
+            /* Insert the next character unconditionally */
+
+            cle_insertch(cle, ch);
+          }
+          break;
+
+        /* Newline terminates editing */
+
+#if defined(CONFIG_EOL_IS_CR)
+        case '\r': /* CR terminates line */
+          {
+            return OK;
+          }
+          break;
+
+#elif defined(CONFIG_EOL_IS_BOTH_CRLF)
+        case '\r': /* Wait for the LF */
+          break;
+#endif
+
+#if defined(CONFIG_EOL_IS_LF) || defined(CONFIG_EOL_IS_BOTH_CRLF)
+        case '\n': /* LF terminates line */
+          {
+            return OK;
+          }
+          break;
+#endif
+
+#ifdef CONFIG_EOL_IS_EITHER_CRLF
+        case '\r': /* Ether CR or LF terminates line */
+        case '\n':
+          {
+            return OK;
+          }
+          break;
+#endif
+        /* Text to insert or unimplemented/invalid keypresses */
+
+        default:
+          {
+            /* Ignore all control characters except for tab and newline */
+
+            if (!iscntrl(ch) || ch == '\t')
+              {
+                /* Insert the filtered character into the buffer */
+
+                cle_insertch(cle, ch);
+              }
+            else
+              {
+                CLE_BEL(cle);
+              }
+          }
+          break;
+        }
+    }
+
+  return OK;
+}
+
+/****************************************************************************
+ * Command line processing
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: cle
+ *
+ * Description:
+ *   EMACS-like command line editor.  This is actually more like readline
+ *   than is the NuttX readline!
+ *
+ ****************************************************************************/
+
+int cle(FAR char *line, uint16_t linelen, FILE *instream, FILE *outstream)
+{
+  FAR struct cle_s cle;
+  uint16_t column;
+  int ret;
+
+  /* Initialize the cle state structure */
+
+  cle.linelen  = linelen;
+  cle.line     = line;
+
+  /* REVISIT:  Non-standard, non-portable */
+
+  cle.infd     = instream->fs_fd;
+  cle.outfd    = outstream->fs_fd;
+
+  /* Get the current cursor position */
+
+  ret = cle_getcursor(&cle, &cle.row, &column);
+  if (ret < 0)
+    {
+      return ret;
+    }
+
+  /* Turn the column number into an offset */
+
+  if (column < 1)
+    {
+      return -EINVAL;
+    }
+
+  cle.coloffs = column - 1;
+
+  /* The editor loop */
+
+  return cle_editloop(&cle);
+}