/****************************************************************************
 * apps/include/system/readline.h
 *
 *   Copyright (C) 2011, 2013, 2015-2016 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_SYSTEM_READLINE_H
#define __APPS_INCLUDE_SYSTEM_READLINE_H

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <nuttx/config.h>
#include <stdio.h>

#ifdef CONFIG_SYSTEM_READLINE

/****************************************************************************
 * Pre-processor Definitions
 ****************************************************************************/
/* Tab completion cannot be supported if there is no console echo */

#ifndef CONFIG_READLINE_ECHO
#  undef CONFIG_READLINE_TABCOMPLETION
#endif

/* Make sure that the are valid values for all tab-completion settings */

#ifdef CONFIG_READLINE_TABCOMPLETION
#  ifndef CONFIG_READLINE_MAX_BUILTINS
#    define CONFIG_READLINE_MAX_BUILTINS 64
#  endif

#  ifndef CONFIG_READLINE_MAX_EXTCMDS
#    define CONFIG_READLINE_MAX_EXTCMDS 64
#  endif
#endif

/****************************************************************************
 * Public Types
 ****************************************************************************/

#if defined(CONFIG_READLINE_TABCOMPLETION) && \
    defined(CONFIG_READLINE_HAVE_EXTMATCH)
struct extmatch_vtable_s
{
  CODE int (*count_matches)(FAR char *name, FAR int *matches, int namelen);
  CODE FAR const char *(*getname)(int index);
};
#endif

/****************************************************************************
 * Public Data
 ****************************************************************************/

#ifdef __cplusplus
#define EXTERN extern "C"
extern "C"
{
#else
#define EXTERN extern
#endif

/****************************************************************************
 * Public Function Prototypes
 ****************************************************************************/

/****************************************************************************
 * Name: readline_prompt
 *
 *   If a prompt string is used by the application, then the application
 *   must provide the prompt string to readline() by calling this function.
 *   This is needed only for tab completion in cases where is it necessary
 *   to reprint the prompt string.
 *
 * Input Parameters:
 *   prompt    - The prompt string. This function may then be
 *   called with that value in order to restore the previous vtable.
 *
 * Returned values:
 *   Returns the previous value of the prompt string.  This function may
 *   then be called with that value in order to restore the previous prompt.
 *
 * Assumptions:
 *   The prompt string is statically allocated a global.  readline() will
 *   simply remember the pointer to the string.  The string must stay
 *   allocated and available.  Only one prompt string is supported.  If
 *   there are multiple clients of readline(), they must all share the same
 *   prompt string (with exceptions in the case of the kernel build).
 *
 ****************************************************************************/

#ifdef CONFIG_READLINE_TABCOMPLETION
FAR const char *readline_prompt(FAR const char *prompt);
#else
#  define readline_prompt(p)
#endif

/****************************************************************************
 * Name: readline_extmatch
 *
 *   If the applications supports a command set, then it may call this
 *   function in order to provide support for tab complete on these
 *   "external"  commands
 *
 * Input Parameters:
 *   vtbl - Callbacks to access the external names.
 *
 * Returned values:
 *   Returns the previous vtable pointer.  This function may then be
 *   called with that value in order to restore the previous vtable.
 *
 * Assumptions:
 *   The vtbl string is statically allocated a global.  readline() will
 *   simply remember the pointer to the structure.  The structure must stay
 *   allocated and available.  Only one instance of such a structure is 
 *   supported.  If there are multiple clients of readline(), they must all
 *   share the same tab-completion logic (with exceptions in the case of
 *   the kernel build).
 *
 ****************************************************************************/

#if defined(CONFIG_READLINE_TABCOMPLETION) && \
    defined(CONFIG_READLINE_HAVE_EXTMATCH)
FAR const struct extmatch_vtable_s *
  readline_extmatch(FAR const struct extmatch_vtable_s *vtbl);
#endif

/****************************************************************************
 * Name: readline
 *
 *   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.
 *
 ****************************************************************************/

#if CONFIG_NFILE_STREAMS > 0
ssize_t readline(FAR char *buf, int buflen, FILE *instream, FILE *outstream);
#endif

/****************************************************************************
 * Name: std_readline
 *
 *   readline() reads in at most one less than 'buflen' characters from
 *   'stdin' and stores them into the buffer pointed to by 'buf'.
 *   Characters are echoed on 'stdout'.  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 'stdin' or 'stdout'
 *   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.
 *
 * 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.
 *
 ****************************************************************************/

#define std_readline(b,s) readline(b,s,stdin,stdout)

#undef EXTERN
#ifdef __cplusplus
}
#endif

#endif /* CONFIG_SYSTEM_READLINE */
#endif /* __APPS_INCLUDE_SYSTEM_READLINE_H */
