shellmatta/src/shellmatta_escape.c

/*
 * Copyright (c) 2019 - 2021 Stefan Strobel <stefan.strobel@shimatta.net>
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at https://mozilla.org/MPL/2.0/.
 */

/**
 * @file    shellmatta_escape.c
 * @brief   functions to parse and generate escape sequences
 * @author  Stefan Strobel <stefan.strobel@shimatta.net>
 */

/**
 * @addtogroup shellmatta_escape
 * @{
 */

#include "shellmatta.h"
#include "shellmatta_escape.h"
#include "shellmatta_utils.h"
#include "shellmatta_history.h"
#include "shellmatta_autocomplete.h"
#include <stdint.h>

/**
 * @brief       processes the excape character stream of the instance and checks
 *              if an arrow key was pressed
 * @param[in]   inst    pointer to a shellmatta instance
 * @return      #SHELLMATTA_OK if an arrow key was pressed
 */
shellmatta_retCode_t escape_processArrowKeys(shellmatta_instance_t *inst)
{
    shellmatta_retCode_t ret = SHELLMATTA_USE_FAULT;

    if ('[' == inst->escapeChars[0])
    {
        ret = SHELLMATTA_OK;

        switch (inst->escapeChars[1])
        {
        case 'A': /* arrow up     */
            history_storeCmd(inst);
            if(false == inst->historyReadUp)
            {
                (void)history_navigate(inst, -1);
            }
            inst->historyReadUp = true;
            history_restoreCmd(inst);
            (void)history_navigate(inst, -1);

            break;
        case 'B': /* arrow down   */
            /*! -# ignore the key if the history buffer points to the last entry */
            if((inst->historyRead != inst->historyEnd))
            {
                history_storeCmd(inst);
                if(true == inst->historyReadUp)
                {
                    (void)history_navigate(inst, 1);
                }
                inst->historyReadUp = false;
                (void)history_navigate(inst, 1);
                history_restoreCmd(inst);
            }
            break;
        case 'C': /* arrow right  */
            utils_forwardCursor(inst, 1u);
            break;
        case 'D': /* arrow left   */
            utils_rewindCursor(inst, 1u);
            break;
        default:
            /** ignore unknown escape */
            ret = SHELLMATTA_USE_FAULT;
            break;
        }
    }
    return ret;
}

/**
 * @brief       handles a ANSI escape sequence to be able to react to some
 *              special keys
 * @param[in]   inst    pointer to a shellmatta instance
 * @param[in]   data    new received character of the escape sequence
 */
void escape_handleSequence(shellmatta_instance_t *inst, char data)
{
    switch (inst->escapeCounter)
    {
    case 1u:
        inst->escapeChars[inst->escapeCounter - 1] = data;
        inst->escapeCounter ++;
        break;
    case 2u:
        inst->escapeChars[inst->escapeCounter - 1] = data;
        /** -# check if an arrow key was pressed */
        if(SHELLMATTA_OK == escape_processArrowKeys(inst))
        {
            inst->escapeCounter = 0u;
        }
        /** -# check if end was pressed */
        else if (   (0x4f == inst->escapeChars[0])
                &&  (0x46 == inst->escapeChars[1]))
        {
            utils_forwardCursor(inst, inst->inputCount - inst->cursor);
            inst->escapeCounter = 0u;
        }
        /** -# if the highest bit is not set this is usually not the end of the
         * sequence - so we go on */
        else if(0u == (0x40 & data))
        {
            inst->escapeCounter ++;
        }
        else
        {
            inst->escapeCounter = 0u;
        }
        break;
    case 3u:
        /** -# check if delete was pressed */
        inst->escapeChars[inst->escapeCounter - 1] = data;
        if(     (0x5b == inst->escapeChars[0])
            &&  (0x33 == inst->escapeChars[1])
            &&  (0x7e == inst->escapeChars[2]))
        {
            utils_removeChars(inst, 1u, false);
            inst->escapeCounter = 0u;
        }
        /** -# check if pos1 was pressed */
        else if (   (0x5bu == inst->escapeChars[0])
                &&  (0x31u == inst->escapeChars[1])
                &&  (0x7eu == inst->escapeChars[2]))
        {
            utils_rewindCursor(inst, inst->cursor);
            inst->escapeCounter = 0u;
        }
        else if(0u == (0x40u & data))
        {
            inst->escapeCounter ++;
        }
        else
        {
            inst->escapeCounter = 0u;
        }
        break;
    default:
        inst->escapeCounter = 0u;
        break;
    }
}

/**
 * @}
 */