/core/src/aos_shell.c - AMiRo-OS - Research for Cognitive Interaction

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       /*
       AMiRo-OS is an operating system designed for the Autonomous Mini Robot (AMiRo) platform.
       Copyright (C) 2016..2020  Thomas Schöpping et al.
       This program is free software: you can redistribute it and/or modify
       it under the terms of the GNU General Public License as published by
       the Free Software Foundation, either version 3 of the License, or
       (at your option) any later version.
       This program is distributed in the hope that it will be useful,
       but WITHOUT ANY WARRANTY; without even the implied warranty of
       MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
       GNU General Public License for more details.
       You should have received a copy of the GNU General Public License
       along with this program.  If not, see <http://www.gnu.org/licenses/>.
       */
       /**
        * @file    aos_shell.c
        * @brief   Shell code.
        * @details Shell code as well as shell related channels and streams.
+       *
        * @addtogroup aos_shell
        * @{
        */
       #include <amiroos.h>
       #include <string.h>
       #if (AMIROOS_CFG_SHELL_ENABLE == true) || defined(__DOXYGEN__)
       /******************************************************************************/
       /* LOCAL DEFINITIONS                                                          */
       /******************************************************************************/
       /**
        * @brief   The character the input buffer is initialized with.
        */
       #define INBUF_INIT_CHAR                         '\x07'
       /**
        * @brief   Event mask to be set on OS related events.
        */
       #define EVENTMASK_OS                            EVENT_MASK(0)
       /**
        * @brief   Event mask to be set on a input event.
        */
       #define EVENTMASK_INPUT                         EVENT_MASK(1)
       /**
        * @brief   String that defines the INSERT key as specified by VT100.
        */
       #define KEYSTRING_INSERT                        "\x1B\x5B\x32\x7E"
       /**
        * @brief   String that defines the DEL key as specified by VT100.
        */
       #define KEYSTRING_DELETE                        "\x1B\x5B\x33\x7E"
       /**
        * @brief   String that defines the HOME key as specified by VT100.
        */
       #define KEYSTRING_HOME                          "\x1B\x5B\x48"
       /**
        * @brief   String that defines the END key as specified by VT100.
        */
       #define KEYSTRING_END                           "\x1B\x5B\x46"
       /**
        * @brief   String that defines the PGUP key as specified by VT100.
        */
       #define KEYSTRING_PAGEUP                        "\x1B\x5B\x35\x7E"
       /**
        * @brief   String that defines the PGUP key as specified by VT100.
        */
       #define KEYSTRING_PAGEDOWN                      "\x1B\x5B\x36\x7E"
       /**
        * @brief   String that defines the 'arrow down' key as specified by VT100.
        */
       #define KEYSTRING_ARROWUP                       "\x1B\x5B\x41"
       /**
        * @brief   String that defines the 'arrow up' key as specified by VT100.
        */
       #define KEYSTRING_ARROWDOWN                     "\x1B\x5B\x42"
       /**
        * @brief   String that defines the 'arrow left' key as specified by VT100.
        */
       #define KEYSTRING_ARROWLEFT                     "\x1B\x5B\x44"
       /**
        * @brief   String that defines the 'arrow right' key as specified by VT100.
        */
       #define KEYSTRING_ARROWRIGHT                    "\x1B\x5B\x43"
       /**
        * @brief   String that defines the CRTL + 'arrow up' key combination as specified by VT100.
        */
       #define KEYSTRING_CTRL_ARROWUP                  "\x1B\x5B\x31\x3B\x35\x41"
       /**
        * @brief   String that defines the CRTL + 'arrow down' key combination as specified by VT100.
        */
       #define KEYSTRING_CTRL_ARROWDOWN                "\x1B\x5B\x31\x3B\x35\x42"
       /**
        * @brief   String that defines the CRTL + 'arrow left' key combination as specified by VT100.
        */
       #define KEYSTRING_CTRL_ARROWLEFT                "\x1B\x5B\x31\x3B\x35\x44"
       /**
        * @brief   String that defines the CRTL + 'arrow right' key combination as specified by VT100.
        */
       #define KEYSTRING_CTRL_ARROWRIGHT               "\x1B\x5B\x31\x3B\x35\x43"
       /******************************************************************************/
       /* EXPORTED VARIABLES                                                         */
       /******************************************************************************/
       /******************************************************************************/
       /* LOCAL TYPES                                                                */
       /******************************************************************************/
       /*
        * forward declarations
        */
       static size_t _channelwrite(void *instance, const uint8_t *bp, size_t n);
       static size_t _channelread(void *instance, uint8_t *bp, size_t n);
       static msg_t _channelput(void *instance, uint8_t b);
       static msg_t _channelget(void *instance);
       static msg_t _channelputt(void *instance, uint8_t b, sysinterval_t time);
       static msg_t _channelgett(void *instance, sysinterval_t time);
       static size_t _channelwritet(void *instance, const uint8_t *bp, size_t n, sysinterval_t time);
       static size_t _channelreadt(void *instance, uint8_t *bp, size_t n, sysinterval_t time);
       static msg_t _channelctl(void *instance, unsigned int operation, void *arg);
       static size_t _streamwrite(void *instance, const uint8_t *bp, size_t n);
       static size_t _stremread(void *instance, uint8_t *bp, size_t n);
       static msg_t _streamput(void *instance, uint8_t b);
       static msg_t _streamget(void *instance);
       static const struct AosShellChannelVMT _channelvmt = {
         (size_t) 0,
         _channelwrite,
         _channelread,
         _channelput,
         _channelget,
         _channelputt,
         _channelgett,
         _channelwritet,
         _channelreadt,
         _channelctl,
       };
       static const struct AosShellStreamVMT _streamvmt = {
         (size_t) 0,
         _streamwrite,
         _stremread,
         _streamput,
         _streamget,
       };
       /**
        * @brief   Enumerator of special keyboard keys.
        */
       typedef enum special_key {
         KEY_UNKNOWN,          /**< any/unknow key */
         KEY_AMBIGUOUS,        /**< key is ambiguous */
         KEY_TAB,              /**< tabulator key */
         KEY_BACKSPACE,        /**< backspace key */
         KEY_INSERT,           /**< insert key */
         KEY_DELETE,           /**< delete key */
         KEY_ESCAPE,           /**< escape key */
         KEY_HOME,             /**< home key */
         KEY_END,              /**< end key */
         KEY_PAGEUP,           /**< page up key */
         KEY_PAGEDOWN,         /**< page down key */
         KEY_ARROWUP,          /**< arrow up key */
         KEY_ARROWDOWN,        /**< arrow down key */
         KEY_ARROWLEFT,        /**< arrow left key */
         KEY_ARROWRIGHT,       /**< arrow right key */
         KEY_CTRL_ARROWUP,     /**< CTRL + arrow up key */
         KEY_CTRL_ARROWDOWN,   /**< CTRL + arrow down key */
         KEY_CTRL_ARROWLEFT,   /**< CTRL + arrow left key */
         KEY_CTRL_ARROWRIGHT,  /**< CTRL + arrow right key */
         KEY_CTRL_C,           /**< CTRL + C key */
       } special_key_t;
       /**
        * @brief   Enumerator for case (in)sensitive character matching.
        */
       typedef enum charmatch {
         CHAR_MATCH_NOT    = 0,  /**< Characters do not match at all. */
         CHAR_MATCH_NCASE  = 1,  /**< Characters would match case insensitive. */
         CHAR_MATCH_CASE   = 2,  /**< Characters do match with case. */
       } charmatch_t;
       /**
        * @brief   Enumerator to encode shell actions.
        */
       typedef enum aos_shellaction {
         ACTION_NONE,                  /**< No action at all. */
         ACTION_READCHAR,              /**< Read a printable character. */
         ACTION_AUTOCOMPLETE,          /**< Automatically comlete input by using available command. */
         ACTION_SUGGEST,               /**< Suggest matching available commands. */
         ACTION_EXECUTE,               /**< Execute input. */
         ACTION_DELETEBACKWARD,        /**< Delete a single character backwards. */
         ACTION_DELETEFORWARD,         /**< Delete a single character forwards. */
         ACTION_CLEAR,                 /**< Clear the input. */
         ACTION_RECALLPREVIOUS,        /**< Recall the previous (older) entry in the history. */
         ACTION_RECALLNEXT,            /**< Recall the next (more recent) entry in the history. */
         ACTION_RECALLOLDEST,          /**< Recall the oldest entry in the history. */
         ACTION_RECALLCURRENT,         /**< Recall the current input. */
         ACTION_CURSORLEFT,            /**< Move cursor one character to the left. */
         ACTION_CURSORRIGHT,           /**< Move cursor one character to the right. */
         ACTION_CURSORWORDLEFT,        /**< Move cursor one word to the left. */
         ACTION_CURSORWORDRIGHT,       /**< Move cursor one word to the right. */
         ACTION_CURSOR2END,            /**< Move cursor to the very right. */
         ACTION_CURSOR2START,          /**< Move cursor to the very left. */
         ACTION_RESET,                 /**< Reset the current input. */
         ACTION_INSERTTOGGLE,          /**< Toggle insertion mode. */
         ACTION_ESCSTART,              /**< Start an escape sequence (special keys). */
         ACTION_PRINTUNKNOWNSEQUENCE,  /**< Print an unknown escape sequence. */
       } action_t;
       /**
        * @brief   Struct that holds most important runtime data for the shell.
        * @details The structure is to be used by the shell thread main function as some kind of structured stack, which can be easily passed to other functions.
        */
       typedef struct runtimedata {
         /**
          * @brief   Data related to the current input.
          */
         struct {
           /**
            * @brief   Length of the input.
            */
           size_t length;
           /**
            * @brief   Current position of the cursor in the input line.
            */
           size_t cursorpos;
           /**
            * @brief   Buffer to store escape sequences, which describe special characters.
            */
           char escseq[AOS_SHELL_ESCSEQUENCE_LENGTH];
         } input;
         /**
          * @brief   Data related to the entry or history buffer.
          */
         struct {
           /**
            * @brief   Current entry to be filled and executed.
            */
           size_t current;
           /**
            * @brief   Selected entry in the 'history' as preview.
            * @details A value of 0 indicates, that the line is cleared as a preview.
            *          A value of 1 indicates, that the current entry is selected.
            *          A value of t>1 indicates, that the entry t-1 in the past is selected.
            *          The value must never be greater than the number of entries available, of course.
            */
           size_t selected;
           /**
            * @brief   Selected entry in the 'history' that has been edited by the user.
            *          A value of 0 indicates, that there was no modification by the user yet (i.e. charcters, deletions or autofill).
            *          A value of 1 indicates, that the current entry was edited.
            *          A value of t>1 indicated, that a history entry was recalled and then edited.
            */
           size_t edited;
         } buffer;
         /**
          * @brief   The last action executed by the shell.
          */
         action_t lastaction;
       } runtimedata_t;
       /******************************************************************************/
       /* LOCAL VARIABLES                                                            */
       /******************************************************************************/
       /******************************************************************************/
       /* LOCAL FUNCTIONS                                                            */
       /******************************************************************************/
       /**
        * @brief   Implementation of the BaseAsynchronous write() method (inherited from BaseSequentialStream).
        */
       static size_t _channelwrite(void *instance, const uint8_t *bp, size_t n)
+      {
         if (((AosShellChannel*)instance)->flags & AOS_SHELLCHANNEL_OUTPUT_ENABLED) {
           return streamWrite(((AosShellChannel*)instance)->asyncchannel, bp, n);
         } else {
           return 0;
+        }
+      }
       /**
        * @brief   Implementation of the BaseAsynchronous read() method (inherited from BaseSequentialStream).
        */
       static size_t _channelread(void *instance, uint8_t *bp, size_t n)
+      {
         if (((AosShellChannel*)instance)->flags & AOS_SHELLCHANNEL_INPUT_ENABLED) {
           return streamRead(((AosShellChannel*)instance)->asyncchannel, bp, n);
         } else {
           return 0;
+        }
+      }
       /**
        * @brief   Implementation of the BaseAsynchronous put() method (inherited from BaseSequentialStream).
        */
       static msg_t _channelput(void *instance, uint8_t b)
+      {
         if (((AosShellChannel*)instance)->flags & AOS_SHELLCHANNEL_OUTPUT_ENABLED) {
           return streamPut(((AosShellChannel*)instance)->asyncchannel, b);
         } else {
           return MSG_RESET;
+        }
+      }
       /**
        * @brief   Implementation of the BaseAsynchronous get() method (inherited from BaseSequentialStream).
        */
       static msg_t _channelget(void *instance)
+      {
         if (((AosShellChannel*)instance)->flags & AOS_SHELLCHANNEL_INPUT_ENABLED) {
           return streamGet(((AosShellChannel*)instance)->asyncchannel);
         } else {
           return MSG_RESET;
+        }
+      }
       /**
        * @brief   Implementation of the BaseAsynchronous putt() method.
        */
       static msg_t _channelputt(void *instance, uint8_t b, sysinterval_t time)
+      {
         if (((AosShellChannel*)instance)->flags & AOS_SHELLCHANNEL_OUTPUT_ENABLED) {
           return chnPutTimeout(((AosShellChannel*)instance)->asyncchannel, b, time);
         } else {
           return MSG_RESET;
+        }
+      }
       /**
        * @brief   Implementation of the BaseAsynchronous gett() method.
        */
       static msg_t _channelgett(void *instance, sysinterval_t time)
+      {
         if (((AosShellChannel*)instance)->flags & AOS_SHELLCHANNEL_INPUT_ENABLED) {
           return chnGetTimeout(((AosShellChannel*)instance)->asyncchannel, time);
         } else {
           return MSG_RESET;
+        }
+      }
       /**
        * @brief   Implementation of the BaseAsynchronous writet() method.
        */
       static size_t _channelwritet(void *instance, const uint8_t *bp, size_t n, sysinterval_t time)
+      {
         if (((AosShellChannel*)instance)->flags & AOS_SHELLCHANNEL_OUTPUT_ENABLED) {
           return chnWriteTimeout(((AosShellChannel*)instance)->asyncchannel, bp, n, time);
         } else {
           return 0;
+        }
+      }
       /**
        * @brief   Implementation of the BaseAsynchronous readt() method.
        */
       static size_t _channelreadt(void *instance, uint8_t *bp, size_t n, sysinterval_t time)
+      {
         if (((AosShellChannel*)instance)->flags & AOS_SHELLCHANNEL_INPUT_ENABLED) {
           return chnReadTimeout(((AosShellChannel*)instance)->asyncchannel, bp, n, time);
         } else {
           return 0;
+        }
+      }
       /**
        * @brief   Implementation of the BaseAsynchronousChannel ctl() method.
        */
       static msg_t _channelctl(void *instance, unsigned int operation, void *arg)
+      {
         (void) instance;
         switch (operation) {
         case CHN_CTL_NOP:
           osalDbgCheck(arg == NULL);
           break;
         case CHN_CTL_INVALID:
           osalDbgAssert(false, "invalid CTL operation");
           break;
         default:
           break;
+        }
         return MSG_OK;
+      }
       /**
        * @brief   Implementation of the BaseSequentialStream write() method.
        */
       static size_t _streamwrite(void *instance, const uint8_t *bp, size_t n)
+      {
         aosDbgCheck(instance != NULL);
         // local variables
         AosShellChannel* channel = ((AosShellStream*)instance)->channel;
         size_t bytes;
         size_t maxbytes = 0;
         // iterate through the list of channels
         while (channel != NULL) {
           bytes = streamWrite(channel, bp, n);
           maxbytes = (bytes > maxbytes) ? bytes : maxbytes;
           channel = channel->next;
+        }
         return maxbytes;
+      }
       /**
        * @brief   Implementation of the BaseSequentialStream read() method.
        */
       static size_t _stremread(void *instance, uint8_t *bp, size_t n)
+      {
         (void)instance;
         (void)bp;
         (void)n;
         return 0;
+      }
       /**
        * @brief   Implementation of the BaseSequentialStream put() method.
        */
       static msg_t _streamput(void *instance, uint8_t b)
+      {
         aosDbgCheck(instance != NULL);
         // local variables
         AosShellChannel* channel = ((AosShellStream*)instance)->channel;
         msg_t ret = MSG_OK;
         // iterate through the list of channels
         while (channel != NULL) {
           msg_t ret_ = streamPut(channel, b);
           ret = (ret_ < ret) ? ret_ : ret;
           channel = channel->next;
+        }
         return ret;
+      }
       /**
        * @brief   Implementation of the BaseSequentialStream get() method.
        */
       static msg_t _streamget(void *instance)
+      {
         (void)instance;
         return 0;
+      }
       /**
        * @brief   Retreive a pointer to the string buffer of a specified entry in the input buffer.
+       *
        * @param[in] shell   Pointer to a shell object.
        * @param[in] entry   Entry to be retrieved.
+       *
        * @return  Pointer to the entry in the input buffer.
        */
       static inline char* _getAbsoluteEntry(const aos_shell_t* shell, size_t entry)
+      {
         aosDbgCheck(shell != NULL);
         aosDbgCheck(entry < shell->input.nentries);
         return &(shell->input.buffer[entry * shell->input.linewidth * sizeof(char)]);
+      }
       /**
        * @brief   Calculate absolute entry from history offset.
+       *
        * @param[in] shell   Pointer to a shell object.
        * @param[in] rdata   Pointer to a runtime data object.
        * @param[in] offset  Relative offset of the entry to be retreived.
+       *
        * @return  Absolute index of the historic entry.
        */
       static inline size_t _historyOffset2EntryIndex(const aos_shell_t* shell, const runtimedata_t* rdata, size_t offset)
+      {
         aosDbgCheck(shell != NULL);
         aosDbgCheck(rdata != NULL);
         aosDbgCheck(offset < shell->input.nentries);
         return ((shell->input.nentries + rdata->buffer.current - offset) % shell->input.nentries);
+      }
       /**
        * @brief   Retreive a pointer to the string buffer of a historic entry in the input buffer.
+       *
        * @param[in] shell   Pointer to a shell object.
        * @param[in] rdata   Pointer to a runtime data object.
        * @param[in] offset  Relative offset of the entry to be retreived.
+       *
        * @return  Pointer to the entry in the input buffer.
        */
       static inline char* _getRelativeEntry(const aos_shell_t* shell, const runtimedata_t* rdata, size_t offset)
+      {
         aosDbgCheck(shell != NULL);
         aosDbgCheck(rdata != NULL);
         aosDbgCheck(offset < shell->input.nentries);
         return _getAbsoluteEntry(shell, _historyOffset2EntryIndex(shell, rdata, offset));
+      }
       /**
        * @brief   Retreive a pointer to the current entry string in the input buffer.
+       *
        * @param[in] shell   Pointer to a shell object.
        * @param[in] rdata   Pointer to a runtime data object.
+       *
        * @return  Pointer to the string of the current entry in the input buffer.
        */
       static inline char* _getCurrentEntry(const aos_shell_t* shell, const runtimedata_t* rdata)
+      {
         aosDbgCheck(shell != NULL);
         aosDbgCheck(rdata != NULL);
         return _getAbsoluteEntry(shell, rdata->buffer.current);
+      }
       /**
        * @brief   Retreive a pointer to the currently selected entry.
+       *
        * @param[in] shell   Pointer to a shell object.
        * @param[in] rdata   Pointer to a runtime data object.
+       *
        * @return  Pointer to the currently selected entry or NULL if no entry is selected (cleared preview).
        */
       static inline char* _getSelectedEntry(const aos_shell_t* shell, const runtimedata_t* rdata)
+      {
         aosDbgCheck(shell != NULL);
         aosDbgCheck(rdata != NULL);
         if (rdata->buffer.selected > 0) {
           return _getRelativeEntry(shell, rdata, rdata->buffer.selected - 1);
         } else {
           return NULL;
+        }
+      }
       /**
        * @brief   Retreive the currently visualized entry.
+       *
        * @param[in] shell   Pointer to a shell object.
        * @param[in] rdata   Pointer to a runtime data object.
+       *
        * @return  Pointer to the currently visualized entry or NULL if the input has been cleared (cleared preview).
        */
       static inline char* _getVisualisedEntry(const aos_shell_t* shell, const runtimedata_t* rdata)
+      {
         aosDbgCheck(shell != NULL);
         aosDbgCheck(rdata != NULL);
         if (rdata->buffer.selected == 0) {
           // cleared preview, nothing visualized
           return NULL;
         } else {
           if (rdata->buffer.selected == 1 || rdata->buffer.selected == rdata->buffer.edited) {
             // the current or a modified entry is selected
             return _getCurrentEntry(shell, rdata);
           } else {
             // a historic, unmodified entry is selected
             return _getRelativeEntry(shell, rdata, rdata->buffer.selected - 1);
+          }
+        }
+      }
       /**
        * @brief   Print the shell prompt
        * @details Depending on the configuration flags, the system uptime is printed before the prompt string.
+       *
        * @param[in] shell   Pointer to the shell object.
        */
       static void _printPrompt(aos_shell_t* shell)
+      {
         aosDbgCheck(shell != NULL);
         // print some time informattion before prompt if configured
         if (shell->config & (AOS_SHELL_CONFIG_PROMPT_UPTIME | AOS_SHELL_CONFIG_PROMPT_DATETIME)) {
           // printf the system uptime
           if ((shell->config & (AOS_SHELL_CONFIG_PROMPT_UPTIME | AOS_SHELL_CONFIG_PROMPT_DATETIME)) == AOS_SHELL_CONFIG_PROMPT_UPTIME) {
             // get current system uptime
             aos_timestamp_t uptime;
             aosSysGetUptime(&uptime);
             chprintf((BaseSequentialStream*)&shell->stream, "[%01u:%02u:%02u:%02u:%03u:%03u] ",
                      (uint32_t)(uptime / MICROSECONDS_PER_DAY),
                      (uint8_t)(uptime % MICROSECONDS_PER_DAY / MICROSECONDS_PER_HOUR),
                      (uint8_t)(uptime % MICROSECONDS_PER_HOUR / MICROSECONDS_PER_MINUTE),
                      (uint8_t)(uptime % MICROSECONDS_PER_MINUTE / MICROSECONDS_PER_SECOND),
                      (uint16_t)(uptime % MICROSECONDS_PER_SECOND / MICROSECONDS_PER_MILLISECOND),
                      (uint16_t)(uptime % MICROSECONDS_PER_MILLISECOND / MICROSECONDS_PER_MICROSECOND));
+          }
       #if (HAL_USE_RTC == TRUE)
           else if ((shell->config & (AOS_SHELL_CONFIG_PROMPT_UPTIME | AOS_SHELL_CONFIG_PROMPT_DATETIME)) == AOS_SHELL_CONFIG_PROMPT_DATETIME) {
             // get current RTC time
             struct tm dt;
             aosSysGetDateTime(&dt);
             chprintf((BaseSequentialStream*)&shell->stream, "[%02u-%02u-%04u|%02u:%02u:%02u] ",
                      dt.tm_mday,
                      dt.tm_mon + 1,
                      dt.tm_year + 1900,
                      dt.tm_hour,
                      dt.tm_min,
                      dt.tm_sec);
+          }
       #endif /* (HAL_USE_RTC == TRUE) */
           else {
             aosDbgAssert(false);
+          }
+        }
         // print the actual prompt string
         if (shell->prompt && !(shell->config & AOS_SHELL_CONFIG_PROMPT_MINIMAL)) {
           chprintf((BaseSequentialStream*)&shell->stream, "%s$ ", shell->prompt);
         } else {
           chprintf((BaseSequentialStream*)&shell->stream, "%>$ ");
+        }
         return;
+      }
       /**
        * @brief   Interprete a escape sequence
        * @details This function interpretes escape sequences (starting with ASCII
        *          "Escape" character 0x1B) according to the VT100 / VT52 ANSI escape
        *          sequence definitions.
        * @note    Only the most important escape sequences are implemented yet.
+       *
        * @param[in] seq   Character sequence to interprete.
        *                  Must be terminated by NUL byte.
+       *
        * @return          A @p special_key value.
        */
       static special_key_t _interpreteEscapeSequence(const char seq[])
+      {
         // local variables
         unsigned long strl = 0;
         const unsigned long seql = strlen(seq);
         bool ambiguous = false;
         // TAB
         /* not supported yet; use '\x09' instead */
         // BACKSPACE
         /* not supported yet; use '\x08' instead */
         // ESCAPE
         /* not supported yes; use '\x1B' instead */
         // CTRL + C
         /* not defined yet; use '\x03' instead */
         // INSERT
         if (strncmp(seq, KEYSTRING_INSERT, seql) == 0) {
           strl = strlen(KEYSTRING_INSERT);
           if (seql == strl) {
             return KEY_INSERT;
           } else if (seql < strl) {
             ambiguous = true;
+          }
+        }
         // DELETE
         if (strncmp(seq, KEYSTRING_DELETE, seql) == 0) {
           strl = strlen(KEYSTRING_DELETE);
           if (seql == strl) {
             return KEY_DELETE;
           } else if (seql < strl) {
             ambiguous = true;
+          }
+        }
         // HOME
         if (strncmp(seq, KEYSTRING_HOME, seql) == 0) {
           strl = strlen(KEYSTRING_HOME);
           if (seql == strl) {
             return KEY_HOME;
           } else if (seql < strl) {
             ambiguous = true;
+          }
+        }
         // END
         if (strncmp(seq, KEYSTRING_END, seql) == 0) {
           strl = strlen(KEYSTRING_END);
           if (seql == strl) {
             return KEY_END;
           } else if (seql < strl) {
             ambiguous = true;
+          }
+        }
         // PAGE UP
         if (strncmp(seq, KEYSTRING_PAGEUP, seql) == 0) {
           strl = strlen(KEYSTRING_PAGEUP);
           if (seql == strl) {
             return KEY_PAGEUP;
           } else if (seql < strl) {
             ambiguous = true;
+          }
+        }
         // PAGE DOWN
         if (strncmp(seq, KEYSTRING_PAGEDOWN, seql) == 0) {
           strl = strlen(KEYSTRING_PAGEDOWN);
           if (seql == strl) {
             return KEY_PAGEDOWN;
           } else if (seql < strl) {
             ambiguous = true;
+          }
+        }
         // ARROW UP
         if (strncmp(seq, KEYSTRING_ARROWUP, seql) == 0) {
           strl = strlen(KEYSTRING_ARROWUP);
           if (seql == strl) {
             return KEY_ARROWUP;
           } else if (seql < strl) {
             ambiguous = true;
+          }
+        }
         // ARROW DOWN
         if (strncmp(seq, KEYSTRING_ARROWDOWN, seql) == 0) {
           strl = strlen(KEYSTRING_ARROWDOWN);
           if (seql == strl) {
             return KEY_ARROWDOWN;
           } else if (seql < strl) {
             ambiguous = true;
+          }
+        }
         // ARROW LEFT
         if (strncmp(seq, KEYSTRING_ARROWLEFT, seql) == 0) {
           strl = strlen(KEYSTRING_ARROWLEFT);
           if (seql == strl) {
             return KEY_ARROWLEFT;
           } else if (seql < strl) {
             ambiguous = true;
+          }
+        }
         // ARROW RIGHT
         if (strncmp(seq, KEYSTRING_ARROWRIGHT, seql) == 0) {
           strl = strlen(KEYSTRING_ARROWRIGHT);
           if (seql == strl) {
             return KEY_ARROWRIGHT;
           } else if (seql < strl) {
             ambiguous = true;
+          }
+        }
         // CTRL + ARROW UP
         if (strncmp(seq, KEYSTRING_CTRL_ARROWUP, seql) == 0) {
           strl = strlen(KEYSTRING_CTRL_ARROWUP);
           if (seql == strl) {
             return KEY_CTRL_ARROWUP;
           } else if (seql < strl) {
             ambiguous = true;
+          }
+        }
         // CTRL + ARROW DOWN
         if (strncmp(seq, KEYSTRING_CTRL_ARROWDOWN, seql) == 0) {
           strl = strlen(KEYSTRING_CTRL_ARROWDOWN);
           if (seql == strl) {
             return KEY_CTRL_ARROWDOWN;
           } else if (seql < strl) {
             ambiguous = true;
+          }
+        }
         // CTRL + ARROW LEFT
         if (strncmp(seq, KEYSTRING_CTRL_ARROWLEFT, seql) == 0) {
           strl = strlen(KEYSTRING_CTRL_ARROWLEFT);
           if (seql == strl) {
             return KEY_CTRL_ARROWLEFT;
           } else if (seql < strl) {
             ambiguous = true;
+          }
+        }
         // CTRL + ARROW RIGHT
         if (strncmp(seq, KEYSTRING_CTRL_ARROWRIGHT, seql) == 0) {
           strl = strlen(KEYSTRING_CTRL_ARROWRIGHT);
           if (seql == strl) {
             return KEY_CTRL_ARROWRIGHT;
           } else if (seql < strl) {
             ambiguous = true;
+          }
+        }
         return ambiguous ? KEY_AMBIGUOUS : KEY_UNKNOWN;
+      }
       /**
        * @brief   Move the cursor in the terminal.
+       *
        * @param[in] shell   Pointer to the shell object.
        * @param[in] line    Pointer to the current content of the line.
        * @param[in] from    Starting position of the cursor.
        * @param[in] to      Target position to move the cursor to.
+       *
        * @return            The number of positions moved.
        */
       static int _moveCursor(aos_shell_t* shell, const char* line, size_t from, size_t to)
+      {
         aosDbgCheck(shell != NULL);
         aosDbgCheck(line !=  NULL || from >= to);
         aosDbgCheck(from <= shell->input.linewidth);
         aosDbgCheck(to <= shell->input.linewidth);
         // local variables
         size_t pos = from;
         // move cursor left by printing backspaces
         while (pos > to) {
           streamPut(&shell->stream, '\b');
           --pos;
+        }
         // move cursor right by printing line content
         while (pos < to) {
           streamPut(&shell->stream, (uint8_t)line[pos]);
           ++pos;
+        }
         return (int)pos - (int)from;
+      }
       /**
        * @brief   Print content of a given string to the shell output stream.
+       *
        * @param[in] shell   Pointer to the shell object.
        * @param[in] line    Pointer to the line to be printed.
        * @param[in] from    First position to start printing from.
        * @param[in] to      Position after the last character to print.
+       *
        * @return            Number of characters printed.
        */
       static size_t _printString(aos_shell_t* shell, const char* line, size_t from, size_t to)
+      {
         aosDbgCheck(shell != NULL);
         aosDbgCheck(line != NULL || from >= to);
         aosDbgCheck(from < shell->input.linewidth);
         aosDbgCheck(to <= shell->input.linewidth);
         // local variables
         size_t cnt;
         for (cnt = 0; from + cnt < to; ++cnt) {
           streamPut(&shell->stream, (uint8_t)line[from + cnt]);
+        }
         return cnt;
+      }
       /**
        * @brief   Print a single character to the input buffer and to the output stream.
+       *
        * @param[in] shell   Pointer to the shell object.
        * @param[in] rdata   Pointer to the runtim data object.
        * @param[in] c       Character to print.
+       *
        * @return  Number of successfully handled characters.
        *          The return value can be interpreted as boolean (1 = sucess; 0 = error).
        */
       static int _printChar(aos_shell_t* shell, runtimedata_t* rdata, char c)
+      {
         aosDbgCheck(shell != NULL);
         aosDbgCheck(rdata != NULL);
         // check whether input line is already full
         if (rdata->input.length + 1 >= shell->input.linewidth) {
           return 0;
+        }
         // retreive entry in the input buffer
         char* line = _getCurrentEntry(shell, rdata);
         // overwrite content
         if (shell->config & AOS_SHELL_CONFIG_INPUT_OVERWRITE) {
           line[rdata->input.cursorpos] = c;
           ++rdata->input.cursorpos;
           rdata->input.length = (rdata->input.cursorpos > rdata->input.length) ? rdata->input.cursorpos : rdata->input.length;
           streamPut(&shell->stream, (uint8_t)c);
           return 1;
+        }
         // insert character
         else {
           memmove(&line[rdata->input.cursorpos + 1], &line[rdata->input.cursorpos], rdata->input.length - rdata->input.cursorpos);
           line[rdata->input.cursorpos] = c;
           ++rdata->input.length;
           _printString(shell, line, rdata->input.cursorpos, rdata->input.length);
           ++rdata->input.cursorpos;
           _moveCursor(shell, line, rdata->input.length, rdata->input.cursorpos);
           return 1;
+        }
+      }
       /**
        * @brief   Overwrite the current output with a given line.
        * @details If the current output is longer than the string, the additional characters are cleared.
+       *
        * @param[in] shell   Pointer to a shell object.
        * @param[in] rdata   Pointer to a runtime data object.
        * @param[in] line    The line to be printed.
        */
       static void _overwriteOutput(aos_shell_t* shell, runtimedata_t* rdata, const char* line)
+      {
         aosDbgCheck(shell != NULL);
         aosDbgCheck(rdata != NULL);
         aosDbgCheck(line != NULL);
         // local variables
         const size_t oldlength = rdata->input.length;
         // print line (overwrite current output)
         _moveCursor(shell, line, rdata->input.cursorpos, 0);
         rdata->input.length = strlen(line);
         _printString(shell, line, 0, rdata->input.length);
         // clear any remaining symbols
         if (oldlength > rdata->input.length) {
           for (rdata->input.cursorpos = rdata->input.length; rdata->input.cursorpos < oldlength; ++rdata->input.cursorpos) {
             streamPut(&shell->stream, ' ');
+          }
           _moveCursor(shell, line, oldlength, rdata->input.length);
+        }
         rdata->input.cursorpos = rdata->input.length;
         return;
+      }
       /**
        * @brief   Compare two characters.
+       *
        * @param[in] lhs       First character to compare.
        * @param[in] rhs       Second character to compare.
+       *
        * @return              How well the characters match.
        */
       static inline charmatch_t _charcmp(char lhs, char rhs)
+      {
         // if lhs is a upper case letter and rhs is a lower case letter
         if (lhs >= 'A' && lhs <= 'Z' && rhs >= 'a' && rhs <= 'z') {
           return (lhs == (rhs - 'a' + 'A')) ? CHAR_MATCH_NCASE : CHAR_MATCH_NOT;
+        }
         // if lhs is a lower case letter and rhs is a upper case letter
         else if (lhs >= 'a' && lhs <= 'z' && rhs >= 'A' && rhs <= 'Z') {
           return ((lhs - 'a' + 'A') == rhs) ? CHAR_MATCH_NCASE : CHAR_MATCH_NOT;
+        }
         // default
         else {
           return (lhs == rhs) ? CHAR_MATCH_CASE : CHAR_MATCH_NOT;
+        }
+      }
       /**
        * @brief   Maps an character from ASCII to a modified custom encoding.
        * @details The custom character encoding is very similar to ASCII and has the following structure:
        *          0x00=NULL ... 0x40='@' (identically to ASCII)
        *          0x4A='a'; 0x4B='A'; 0x4C='b'; 0x4D='B' ... 0x73='z'; 0x74='Z' (custom letter order)
        *          0x75='[' ... 0x7A='`' (0x5B..0x60 is ASCII)
        *          0x7B='{' ... 0x7F=DEL (identically to ASCII)
+       *
        * @param[in] c   Character to map to the custom encoding.
+       *
        * @return    The customly encoded character.
        */
       static inline char _mapAscii2Custom(char c)
+      {
         if (c >= 'A' && c <= 'Z') {
           return ((c - 'A') * 2) + 'A' + 1;
         } else if (c > 'Z' && c < 'a') {
           return c + ('z' - 'a') + 1;
         } else if (c >= 'a' && c <= 'z') {
           return ((c - 'a') * 2) + 'A';
         } else {
           return c;
+        }
+      }
       /**
        * @brief   Compares two strings wrt letter case.
        * @details Comparisson uses a custom character encoding or mapping.
        *          See @p _mapAscii2Custom for details.
+       *
        * @param[in] str1    First string to compare.
        * @param[in] str2    Second string to compare.
        * @param[in] cs      Flag indicating whether comparison shall be case sensitive.
        * @param[in,out] n   Maximum number of character to compare (in) and number of matching characters (out).
        *                    If a null pointer is specified, this parameter is ignored.
        *                    If the value pointed to is zero, comarison will not be limited.
        * @param[out] m      Optional indicator whether there was at least one case mismatch.
+       *
        * @return      Integer value indicating the relationship between the strings.
        * @retval <0   The first character that does not match has a lower value in str1 than in str2.
        * @retval  0   The contents of both strings are equal.
        * @retval >0   The first character that does not match has a greater value in str1 than in str2.
        */
       static int _strccmp(const char *str1, const char *str2, bool cs, size_t* n, charmatch_t* m)
+      {
         aosDbgCheck(str1 != NULL);
         aosDbgCheck(str2 != NULL);
         // initialize variables
         if (m) {
           *m = CHAR_MATCH_NOT;
+        }
         size_t i = 0;
         // iterate through the strings
         while ((n == NULL) || (*n == 0) || (*n > 0 && i < *n)) {
           // break on NUL
           if (str1[i] == '\0' || str2[i] == '\0') {
             if (n) {
               *n = i;
+            }
             break;
+          }
           // compare character
           const charmatch_t match = _charcmp(str1[i], str2[i]);
           if ((match == CHAR_MATCH_CASE) || (!cs && match == CHAR_MATCH_NCASE)) {
             if (m != NULL && *m != CHAR_MATCH_NCASE) {
               *m = match;
+            }
             ++i;
           } else {
             if (n) {
               *n = i;
+            }
             break;
+          }
+        }
         return _mapAscii2Custom(str1[i]) - _mapAscii2Custom(str2[i]);
+      }
       /**
        * @brief   Alters all intermediate NUL bytes in a string to spaces.
+       *
        * @param[in] string  The string to be handled.
        * @param[in] length  Length of the string.
+       *
        * @return  Detected Length of the actual content of the string.
        */
       static size_t _restoreWhitespace(char* string, size_t length)
+      {
         aosDbgCheck(string != NULL || length == 0);
         // local variables
         size_t c = length;
         // seach for first non-NUL byte from the back
         while (c > 0) {
           --c;
           if (string[c] != '\0') {
             // store the detected length of the content
             length = ++c;
             break;
+          }
+        }
         // iterate further and replace all encountered NUL bytes by spaces
         while (c > 0) {
           --c;
           if (string[c] == '\0') {
             string[c] = ' ';
+          }
+        }
         return length;
+      }
       /**
        * @brief   Performs required actions before an imminent modiifcation (character input, deletion or autofill).
        * @details This functions checks the current status and clears or copies entries in the input buffer as required.
        *          Status information (runtime data) is altered accordingly as well.
+       *
        * @param[in] shell   Pointer to a shell object.
        * @param[in] rdata   Pointer to a runtime data object.
+       *
        * @return    Pointer to the current entry in the input buffer.
        */
       static char* _prepare4Modification(aos_shell_t* shell, runtimedata_t* rdata)
+      {
         aosDbgCheck(shell != NULL);
         aosDbgCheck(rdata != NULL);
         char* line = _getCurrentEntry(shell, rdata);
         // cleared preview
         if (rdata->buffer.selected == 0) {
           // reset the current entry if required
           if (rdata->buffer.edited != 0) {
             memset(line, '\0', shell->input.linewidth * sizeof(char));
+          }
           // set the current entry as the selected one and mark it as edited
           rdata->buffer.selected = 1;
           rdata->buffer.edited = 1;
+        }
         // current entry
         else if (rdata->buffer.selected == 1) {
           // mark current entry as edited
           rdata->buffer.edited = 1;
+        }
         // preview of historic entry
         else if (rdata->buffer.selected > 1) {
           // copy the selected entry before modification if required
           if (rdata->buffer.selected!= rdata->buffer.edited) {
             memcpy(line, _getSelectedEntry(shell, rdata), shell->input.linewidth * sizeof(char));
+          }
           // mark the selected entry as edited
           rdata->buffer.edited = rdata->buffer.selected;
+        }
         return line;
+      }
       /**
        * @brief   Read input from a channel as long as there is data available.
+       *
        * @param[in]     shell     Pointer to the shell object.
        * @param[in,out] rdata     Pointer to a runtime data object.
        * @param[in]     channel   The channel to read from.
+       *
        * @return  Number of characters read.
        */
       static size_t _readChannel(aos_shell_t* shell, runtimedata_t* rdata, AosShellChannel* channel)
+      {
         aosDbgCheck(shell != NULL);
         aosDbgCheck(rdata != NULL);
         aosDbgCheck(channel != NULL);
         // local variables
         size_t bytes = 0;
         char c;
         special_key_t key;
         action_t action;
         // read character by character from the channel
         while (chnReadTimeout(channel, (uint8_t*)&c, 1, TIME_IMMEDIATE)) {
           // increment byte counter
           ++bytes;
           // drop any further input after an execution request was detected
           if (rdata->lastaction == ACTION_EXECUTE && bytes > 1) {
             continue;
+          }
           // try to interprete escape sequence
+          {
             // set default
             key = KEY_UNKNOWN;
             // only interprete, if there is an escape sequence at all
             const size_t escl = strlen(rdata->input.escseq);
             if (escl > 0) {
               // append and 'consume' character
               rdata->input.escseq[escl] = c;
               c = '\0';
               // try to interprete sequence
               key = _interpreteEscapeSequence(rdata->input.escseq);
               switch (key) {
                 // ambiguous key due to incomplete sequence
                 case KEY_AMBIGUOUS:
                   // read next byte to resolve ambiguity
                   continue;
                 // an unknown sequence has been encountered
                 case KEY_UNKNOWN:
                   // increment number of inputs but handle this unknown sequence below
                   break;
                 // a key was identified successfully
                 default:
                   // reset the sequence buffer
                   memset(rdata->input.escseq, '\0', AOS_SHELL_ESCSEQUENCE_LENGTH * sizeof(char));
                   break;
+              }
+            }
+          }
           /*
            * Derive action to be executed from keypress.
            * This step handles all sanity checks, so any required prerequisites for the selected action are fulfilled.
            */
           // set default
           action = ACTION_NONE;
           // if there is no escape sequence pending
           if (rdata->input.escseq[0] == '\0') {
             // printable character
             if (c >= '\x20' && c <= '\x7E') {
               action = ACTION_READCHAR;
+            }
             // tab key or character
             else if (c == '\x09' || key == KEY_TAB) {
               /*
                * pressing tab once applies auto fill
                * pressing tab a second time (or more) prints suggestions
                */
               if (rdata->lastaction == ACTION_AUTOCOMPLETE || rdata->lastaction == ACTION_SUGGEST) {
                 action = ACTION_SUGGEST;
               } else {
                 action = ACTION_AUTOCOMPLETE;
+              }
+            }
             // carriage return ('\r') or line feed ('\n') character
             else if (c == '\x0D' || c == '\x0A') {
               action = ACTION_EXECUTE;
+            }
             // backspace key or character
             else if (c == '\x08' || key == KEY_BACKSPACE) {
               // ignore if cursor is at very left
               if (rdata->input.cursorpos > 0) {
                 action = ACTION_DELETEBACKWARD;
+              }
+            }
             // DEL key or character
             else if (c == '\x7F' || key == KEY_DELETE) {
               // ignore if cursor is at very right
               if (rdata->input.cursorpos < rdata->input.length) {
                 action = ACTION_DELETEFORWARD;
+              }
+            }
             // 'arrow up' key
             else if (key == KEY_ARROWUP) {
               // recall previous input from history only if
               // not the oldest entry is already selected and
               // the previous entry has been set.
               if (rdata->buffer.selected < shell->input.nentries &&
                   (_getRelativeEntry(shell, rdata, rdata->buffer.selected))[0] != INBUF_INIT_CHAR) {
                 action = ACTION_RECALLPREVIOUS;
+              }
+            }
             // 'arrow down' key
             else if (key == KEY_ARROWDOWN) {
               // clear the line if
               // no historic entry is selected or
               // the most recent entry is selected, but the current one is occupied by a moodfied version of a historic entry
               if ((rdata->buffer.selected == 1) ||
                   (rdata->buffer.selected == 2 && rdata->buffer.edited > 1)) {
                 action = ACTION_CLEAR;
+              }
               // if a historic entry is selected, recall the next input from history
               else if (rdata->buffer.selected > 1) {
                 action = ACTION_RECALLNEXT;
+              }
+            }
             // 'arrow left' key
             else if (key == KEY_ARROWLEFT) {
               // ignore if cursor is very left
               if (rdata->input.cursorpos > 0) {
                 action = ACTION_CURSORLEFT;
+              }
+            }
             // 'arrow right' key
             else if (key == KEY_ARROWRIGHT) {
               // ignore if cursor is very right
               if (rdata->input.cursorpos < rdata->input.length) {
                 action = ACTION_CURSORRIGHT;
+              }
+            }
             // CTRL + 'arrow up' key combination or 'page up' key
             else if (key == KEY_CTRL_ARROWUP || key == KEY_PAGEUP) {
               // recall oldest input from history only if
               // not the oldest entry is already selected and
               // there is at least one history entry set
               if (rdata->buffer.selected < shell->input.nentries &&
                   (_getRelativeEntry(shell, rdata, (rdata->buffer.selected > 0) ? 1 : 0))[0] != INBUF_INIT_CHAR) {
                 action = ACTION_RECALLOLDEST;
+              }
+            }
             // CTRL + 'arrow down' key combination or 'page down' key
             else if (key == KEY_CTRL_ARROWDOWN || key == KEY_PAGEDOWN) {
               // clear the line if
               // no historic entry is selected or
               // the most recent entry is selected, but the current one is occupied by a moodfied version of a historic entry
               if ((rdata->buffer.selected == 1) ||
                   (rdata->buffer.selected > 1 && rdata->buffer.edited > 1)) {
                 action = ACTION_CLEAR;
+              }
               // if a historic entry is selected, reset to the current input
               else if (rdata->buffer.selected > 1) {
                 action = ACTION_RECALLCURRENT;
+              }
+            }
             // CTRL + 'arrow left' key combination
             else if (key == KEY_CTRL_ARROWLEFT) {
               // ignore if cursor is very left
               if (rdata->input.cursorpos > 0) {
                 action = ACTION_CURSORWORDLEFT;
+              }
+            }
             // CTRL + 'arrow right' key combination
             else if (key == KEY_CTRL_ARROWRIGHT) {
               // ignore if cursor is very right
               if (rdata->input.cursorpos < rdata->input.length) {
                 action = ACTION_CURSORWORDRIGHT;
+              }
+            }
             // 'end' key
             else if (key == KEY_END) {
               // ignore if cursos is very right
               if (rdata->input.cursorpos < rdata->input.length) {
                 action = ACTION_CURSOR2END;
+              }
+            }
             // 'home' key
             else if (key == KEY_HOME) {
               // ignore if cursor is very left
               if (rdata->input.cursorpos > 0) {
                 action = ACTION_CURSOR2START;
+              }
+            }
             // CTRL + C key combination
             else if (c == '\x03' || key == KEY_CTRL_C) {
               action = ACTION_RESET;
+            }
             // INS key
             else if (key == KEY_INSERT) {
               action = ACTION_INSERTTOGGLE;
+            }
             // ESC key or [ESCAPE] character
             else if (c == '\x1B' || key == KEY_ESCAPE) {
               action = ACTION_ESCSTART;
+            }
+          }
           // ongoing escape sequence or interpretation failed
           else /* if (rdata->input.escseq[0] != '\0') */ {
             // unknown escape sequence (interpretation failed)
             if (key == KEY_UNKNOWN) {
               action = ACTION_PRINTUNKNOWNSEQUENCE;
+            }
           } /* end of action selection */
           /*
            * execute action
            */
           switch (action) {
             case ACTION_NONE:
+            {
               // do nothing (ignore input) and read next byte
               break;
+            }
             case ACTION_READCHAR:
+            {
               char* line = _prepare4Modification(shell, rdata);
               if (_printChar(shell, rdata, c) == 0) {
                 // line is full
                 _moveCursor(shell, line, rdata->input.cursorpos, rdata->input.length);
                 chprintf((BaseSequentialStream*)&shell->stream, "\n\tmaximum line width reached\n");
                 _printPrompt(shell);
                 _printString(shell, line, 0, rdata->input.length);
                 _moveCursor(shell, line, rdata->input.length, rdata->input.cursorpos);
+              }
               break;
+            }
             case ACTION_AUTOCOMPLETE:
+            {
               // local variables
               char* line = _getVisualisedEntry(shell, rdata);
               const char* fill = line;
               size_t cmatch = rdata->input.cursorpos;
               charmatch_t matchlevel = CHAR_MATCH_NOT;
               size_t n;
               // only execute autofill if the line is valid
               if (line) {
                 _prepare4Modification(shell, rdata);
                 // iterate through command list
                 for (aos_shellcommand_t* cmd = shell->commands; cmd != NULL; cmd = cmd->next) {
                   // compare current match with command
                   n = cmatch;
                   charmatch_t mlvl = CHAR_MATCH_NOT;
                   _strccmp(fill, cmd->name, shell->config & AOS_SHELL_CONFIG_MATCH_CASE, (n == 0) ? NULL : &n, &mlvl);
                   const int cmp = (n < cmatch) ?
                         ((int)n - (int)cmatch) :
                         (cmd->name[n] != '\0') ?
                           (int)strlen(cmd->name) - (int)n :
 ;
                   // if an exact match was found
                   if ((size_t)((int)cmatch + cmp) == rdata->input.cursorpos) {
                     cmatch = rdata->input.cursorpos;
                     fill = cmd->name;
                     // break the loop only if there are no case mismatches with the input
                     n = rdata->input.cursorpos;
                     _strccmp(fill, line, false, &n, &mlvl);
                     if (mlvl == CHAR_MATCH_CASE) {
                       break;
+                    }
+                  }
                   // if a not exact match was found
                   else if ((size_t)((int)cmatch + cmp) > rdata->input.cursorpos) {
                     // if this is the first one
                     if (fill == line) {
                       cmatch = (size_t)((int)cmatch + cmp);
                       fill = cmd->name;
+                    }
                     // if this is a worse one
                     else if ((cmp < 0) || (cmp == 0 && mlvl == CHAR_MATCH_CASE)) {
                       cmatch = (size_t)((int)cmatch + cmp);
+                    }
+                  }
                   // non matching commands are ignored
                   else {}
+                }
                 // evaluate if there are case mismatches
                 n = cmatch;
                 _strccmp(line, fill, shell->config & AOS_SHELL_CONFIG_MATCH_CASE, &n, &matchlevel);
                 // print the auto fill if any
                 if (cmatch > rdata->input.cursorpos || (cmatch == rdata->input.cursorpos && matchlevel == CHAR_MATCH_NCASE)) {
                   // limit auto fill so it will not overflow the line width
                   if (rdata->input.length + (cmatch - rdata->input.cursorpos) > shell->input.linewidth) {
                     cmatch = shell->input.linewidth - rdata->input.length + rdata->input.cursorpos;
+                  }
                   // move trailing memory further in the line
                   memmove(&line[cmatch], &line[rdata->input.cursorpos], (rdata->input.length - rdata->input.cursorpos) * sizeof(char));
                   rdata->input.length += cmatch - rdata->input.cursorpos;
                   // if there was no incorrect case when matching
                   if (matchlevel == CHAR_MATCH_CASE) {
                     // insert fill command name to line
                     memcpy(&line[rdata->input.cursorpos], &fill[rdata->input.cursorpos], (cmatch - rdata->input.cursorpos) * sizeof(char));
                     // print the output
                     _printString(shell, line, rdata->input.cursorpos, rdata->input.length);
                   } else {
                     // overwrite line with fill command name
                     memcpy(line, fill, cmatch * sizeof(char));
                     // reprint the whole line
                     _moveCursor(shell, line, rdata->input.cursorpos, 0);
                     _printString(shell, line, 0, rdata->input.length);
+                  }
                   // move cursor to the end of the matching sequence
                   rdata->input.cursorpos = cmatch;
                   _moveCursor(shell, line, rdata->input.length, rdata->input.cursorpos);
+                }
+              }
               break;
+            }
             case ACTION_SUGGEST:
+            {
               // local variables
               const char* line = _getVisualisedEntry(shell, rdata);
               unsigned int matches = 0;
               // iterate through command list
               for (aos_shellcommand_t* cmd = shell->commands; cmd != NULL; cmd = cmd->next) {
                 // compare line content with command, except if cursorpos is 0
                 size_t i = rdata->input.cursorpos;
                 if (rdata->input.cursorpos > 0) {
                   _strccmp(line, cmd->name, true, &i, NULL);
+                }
                 const int cmp = (i < rdata->input.cursorpos) ?
                       ((int)i - (int)rdata->input.cursorpos) :
                       (cmd->name[i] != '\0') ?
                         (int)strlen(cmd->name) - (int)i :
 ;
                 // if a match was found
                 if (cmp > 0) {
                   // if this is the first one
                   if (matches == 0) {
                     _moveCursor(shell, line, rdata->input.cursorpos, rdata->input.length);
                     streamPut(&shell->stream, '\n');
+                  }
                   // print the command
                   chprintf((BaseSequentialStream*)&shell->stream, "\t%s\n", cmd->name);
                   ++matches;
+                }
+              }
               // reprint the prompt and line if any matches have been found
               if (matches > 0) {
                 _printPrompt(shell);
                 _printString(shell, line, 0, rdata->input.length);
                 _moveCursor(shell, line, rdata->input.length, rdata->input.cursorpos);
+              }
               break;
+            }
             case ACTION_EXECUTE:
+            {
               // if the input buffer can hold historic entries
               if (shell->input.nentries > 1) {
                 _prepare4Modification(shell, rdata);
+              }
               break;
+            }
             case ACTION_DELETEBACKWARD:
+            {
               char* line = _prepare4Modification(shell, rdata);
               --rdata->input.cursorpos;
               memmove(&line[rdata->input.cursorpos], &line[rdata->input.cursorpos + 1], (rdata->input.length - rdata->input.cursorpos) * sizeof(char));
               --rdata->input.length;
               line[rdata->input.length] = '\0';
               _moveCursor(shell, line, rdata->input.cursorpos + 1, rdata->input.cursorpos);
               _printString(shell, line, rdata->input.cursorpos, rdata->input.length);
               streamPut(&shell->stream, ' ');
               _moveCursor(shell, line, rdata->input.length + 1, rdata->input.cursorpos);
               break;
+            }
             case ACTION_DELETEFORWARD:
+            {
               char* line = _prepare4Modification(shell, rdata);
               --rdata->input.length;
               memmove(&line[rdata->input.cursorpos], &line[rdata->input.cursorpos + 1], (rdata->input.length - rdata->input.cursorpos) * sizeof(char));
               _printString(shell, line, rdata->input.cursorpos, rdata->input.length);
               streamPut(&shell->stream, ' ');
               _moveCursor(shell, line, rdata->input.length + 1, rdata->input.cursorpos);
               break;
+            }
             case ACTION_CLEAR:
+            {
               // clear visualization
               _moveCursor(shell, NULL, rdata->input.cursorpos, 0);
               for (size_t cpos = 0; cpos < rdata->input.length; ++cpos) {
                 streamPut(&shell->stream, ' ');
+              }
               _moveCursor(shell, NULL, rdata->input.length, 0);
               // update metadata
               rdata->input.cursorpos = 0;
               rdata->input.length = 0;
               rdata->buffer.selected = 0;
               break;
+            }
             case ACTION_RECALLPREVIOUS:
+            {
               // if the input was cleared but the current entry is occupied by a modified copy of a history entry, skip the current entry
               if (rdata->buffer.selected == 0 && rdata->buffer.edited > 1) {
                 rdata->buffer.selected += 2;
               } else {
                 ++rdata->buffer.selected;
+              }
               _overwriteOutput(shell, rdata, _getVisualisedEntry(shell, rdata));
               break;
+            }
             case ACTION_RECALLNEXT:
+            {
               --rdata->buffer.selected;
               _overwriteOutput(shell, rdata, _getVisualisedEntry(shell, rdata));
               break;
+            }
             case ACTION_RECALLOLDEST:
+            {
               // find oldest valid entry
               rdata->buffer.selected = shell->input.nentries;
               while (_getSelectedEntry(shell, rdata)[0] == INBUF_INIT_CHAR) {
                 --rdata->buffer.selected;
+              }
               _overwriteOutput(shell, rdata, _getVisualisedEntry(shell, rdata));
               break;
+            }
             case ACTION_RECALLCURRENT:
+            {
               rdata->buffer.selected = 1;
               _overwriteOutput(shell, rdata, _getVisualisedEntry(shell, rdata));
               break;
+            }
             case ACTION_CURSORLEFT:
+            {
               _moveCursor(shell, NULL, rdata->input.cursorpos, rdata->input.cursorpos - 1);
               --rdata->input.cursorpos;
               break;
+            }
             case ACTION_CURSORRIGHT:
+            {
               _moveCursor(shell, _getVisualisedEntry(shell, rdata), rdata->input.cursorpos, rdata->input.cursorpos + 1);
               ++rdata->input.cursorpos;
               break;
+            }
             case ACTION_CURSORWORDLEFT:
+            {
               // local variables
               const char* line = _getVisualisedEntry(shell, rdata);
               size_t cpos = rdata->input.cursorpos;
               // skip spaces
               while (cpos > 0) {
                 --cpos;
                 if (line[cpos] != ' ') {
                   break;
+                }
+              }
               // search for beginning of the word
               while (cpos > 0) {
                 --cpos;
                 if (line[cpos] == ' ') {
                   // go back to first character of the word
                   ++cpos;
                   break;
+                }
+              }
               // move the cursor and set metadata
               _moveCursor(shell, line, rdata->input.cursorpos, cpos);
               rdata->input.cursorpos = cpos;
               break;
+            }
             case ACTION_CURSORWORDRIGHT:
+            {
               // local variables
               const char* line = _getVisualisedEntry(shell, rdata);
               size_t cpos = rdata->input.cursorpos;
               // skip spaces
               while (cpos < rdata->input.length && line[cpos] == ' ') {
                 ++cpos;
+              }
               // search for end of the word
               while (cpos < rdata->input.length && line[cpos] != ' ') {
                 ++cpos;
+              }
               // move cursor and set metadata
               _moveCursor(shell, line, rdata->input.cursorpos, cpos);
               rdata->input.cursorpos = cpos;
               break;
+            }
             case ACTION_CURSOR2END:
+            {
               _moveCursor(shell, _getVisualisedEntry(shell, rdata), rdata->input.cursorpos, rdata->input.length);
               rdata->input.cursorpos = rdata->input.length;
               break;
+            }
             case ACTION_CURSOR2START:
+            {
               _moveCursor(shell, _getVisualisedEntry(shell, rdata), rdata->input.cursorpos, 0);
               rdata->input.cursorpos = 0;
               break;
+            }
             case ACTION_RESET:
+            {
               // print reset indicator
               chprintf((BaseSequentialStream*)&shell->stream, "^C");
               if (!(shell->config & AOS_SHELL_CONFIG_INPUT_OVERWRITE)) {
                 _printString(shell, _getVisualisedEntry(shell, rdata), rdata->input.cursorpos, rdata->input.length);
+              }
               chprintf((BaseSequentialStream*)&shell->stream, "\n");
               // reset buffers and metadata
               if (rdata->buffer.edited != 0) {
                 memset(_getCurrentEntry(shell, rdata), '\0', shell->input.linewidth * sizeof(char));
+              }
               rdata->input.length = 0;
               rdata->input.cursorpos = 0;
               rdata->buffer.selected = (shell->input.nentries > 1) ? 1 : 0;
               rdata->buffer.edited = 0;
               // print a new prompt
               _printPrompt(shell);
               break;
+            }
             case ACTION_INSERTTOGGLE:
+            {
               if (shell->config & AOS_SHELL_CONFIG_INPUT_OVERWRITE) {
                 shell->config &= ~AOS_SHELL_CONFIG_INPUT_OVERWRITE;
               } else {
                 shell->config |= AOS_SHELL_CONFIG_INPUT_OVERWRITE;
+              }
               break;
+            }
             case ACTION_ESCSTART:
+            {
               rdata->input.escseq[0] = c;
               break;
+            }
             case ACTION_PRINTUNKNOWNSEQUENCE:
+            {
               _prepare4Modification(shell, rdata);
               for (size_t seqc = 1; rdata->input.escseq[seqc] != '\0'; ++seqc) {
                 // element 0 would be unprintable ESC character
                 _printChar(shell, rdata, rdata->input.escseq[seqc]);
+              }
               memset(rdata->input.escseq, '\0', AOS_SHELL_ESCSEQUENCE_LENGTH * sizeof(char));
               break;
+            }
+          }
           // update runtime data
           rdata->lastaction = (action != ACTION_NONE) ? action : rdata->lastaction;
         } /* end of while */
         return bytes;
+      }
       /**
        * @brief   Parses the content of the given string to separate arguments.
+       *
        * @param[in]   shell   Pointer to the shell object.
        * @param[in]   str     String to be parsed.
        * @param[out]  argbuf  Buffer to store argument pointers to.
+       *
        * @return            Number of arguments found.
        */
       static size_t _parseArguments(aos_shell_t* shell, char* str, char** argbuf)
+      {
         aosDbgCheck(shell != NULL);
         aosDbgCheck(str != NULL);
         aosDbgCheck(argbuf != NULL);
         /*
          * States for a very small FSM.
          */
         typedef enum {
           START,
           SPACE,
           TEXT,
           END,
         } state_t;
         // local variables
         state_t state = START;
         size_t nargs = 0;
         // iterate through the line
         for (size_t c = 0; c < shell->input.linewidth; ++c) {
           // terminate at first NUL byte
           if (str[c] == '\0') {
             state = END;
             break;
+          }
           // spaces become NUL bytes
           else if (str[c] == ' ') {
             str[c] = '\0';
             state = SPACE;
+          }
           // handle non-NUL bytes
           else {
             switch (state) {
               case START:
               case SPACE:
                 // ignore too many arguments
                 if (nargs < shell->input.nargs) {
                   argbuf[nargs] = &str[c];
+                }
                 ++nargs;
                 break;
               case TEXT:
               case END:
                 break;
+            }
             state = TEXT;
+          }
+        }
         // set all remaining argument pointers to NULL
         for (size_t a = nargs; a < shell->input.nargs; ++a) {
           argbuf[a] = NULL;
+        }
         return nargs;
+      }
       /******************************************************************************/
       /* EXPORTED FUNCTIONS                                                         */
       /******************************************************************************/
       /**
        * @brief   Initializes a shell object with the specified parameters.
+       *
        * @param[in,out] shell           Pointer to the shell object to be initialized.
        * @param[in]     prompt          Prompt line to print (NULL = use default prompt).
        * @param[in]     inbuf           Two dimensional input buffer.
        * @param[in]     entries         Number of entries in the input buffer (1st dimension).
        * @param[in]     linewidth       Length of each entry in the input buffer (2nd dimension).
        * @param[in]     numargs         Maximum number of arguments (defines size of internal buffer).
        */
       void aosShellInit(aos_shell_t* shell, const char* prompt, char inbuf[], size_t entries, size_t linewidth, size_t numargs)
+      {
         aosDbgCheck(shell != NULL);
         aosDbgCheck(inbuf != NULL);
         aosDbgCheck(entries > 0);
         aosDbgCheck(linewidth > 0);
         aosDbgCheck(numargs > 0);
         // set parameters
         shell->thread = NULL;
         chEvtObjectInit(&shell->eventSource);
         aosShellStreamInit(&shell->stream);
         shell->prompt = prompt;
         shell->commands = NULL;
         shell->execstatus.command = NULL;
         shell->execstatus.retval = 0;
         shell->input.buffer = inbuf;
         shell->input.nentries = entries;
         shell->input.linewidth = linewidth;
         shell->input.nargs = numargs;
         shell->config = 0x00;
         // initialize buffers
         memset(shell->input.buffer, INBUF_INIT_CHAR, shell->input.nentries * shell->input.linewidth * sizeof(char));
         return;
+      }
       /**
        * @brief   Initialize an AosShellStream object.
+       *
        * @param[in] stream  The AosShellStrem to initialize.
        */
       void aosShellStreamInit(AosShellStream* stream)
+      {
         aosDbgCheck(stream != NULL);
         stream->vmt = &_streamvmt;
         stream->channel = NULL;
         return;
+      }
       /**
        * @brief   Initialize an AosShellChannel object with the specified parameters.
+       *
        * @param[in] channel       The AosShellChannel to initialize.
        * @param[in] asyncchannel  An BaseAsynchronousChannel this AosShellChannel is associated with.
        */
       void aosShellChannelInit(AosShellChannel* channel, BaseAsynchronousChannel* asyncchannel)
+      {
         aosDbgCheck(channel != NULL);
         aosDbgCheck(asyncchannel != NULL);
         channel->vmt = &_channelvmt;
         channel->asyncchannel = asyncchannel;
         channel->listener.wflags = 0;
         channel->next = NULL;
         channel->flags = 0;
         return;
+      }
       /**
        * @brief   Inserts a command to the shells list of commands.
+       *
        * @param[in] shell   Pointer to the shell object.
        * @param[in] cmd     Pointer to the command to add.
+       *
        * @return            A status value.
        * @retval AOS_SUCCESS  The command was added successfully.
        * @retval AOS_ERROR    Another command with identical name already exists.
        */
       aos_status_t aosShellAddCommand(aos_shell_t *shell, aos_shellcommand_t *cmd)
+      {
         aosDbgCheck(shell != NULL);
         aosDbgCheck(cmd != NULL);
         aosDbgCheck(cmd->name != NULL && strlen(cmd->name) > 0 && strchr(cmd->name, ' ') == NULL && strchr(cmd->name, '\t') == NULL);
         aosDbgCheck(cmd->callback != NULL);
         aosDbgCheck(cmd->next == NULL);
         aos_shellcommand_t* prev = NULL;
         aos_shellcommand_t** curr = &(shell->commands);
         // insert the command to the list wrt lexographical order (exception: lower case characters preceed upper their uppercase counterparts)
         while (*curr != NULL) {
           // iterate through the list as long as the command names are 'smaller'
           const int cmp = _strccmp((*curr)->name, cmd->name, true, NULL, NULL);
           if (cmp < 0) {
             prev = *curr;
             curr = &((*curr)->next);
             continue;
+          }
           // error if the command already exists
           else if (cmp == 0) {
             return AOS_ERROR;
+          }
           // insert the command as soon as a 'larger' name was found
           else /* if (cmpval > 0) */ {
             cmd->next = *curr;
             // special case: the first command is larger
             if (prev == NULL) {
               shell->commands = cmd;
             } else {
               prev->next = cmd;
+            }
             return AOS_SUCCESS;
+          }
+        }
         // the end of the list has been reached
         // append the command
         *curr = cmd;
         return AOS_SUCCESS;
+      }
       /**
        * @brief   Removes a command from the shells list of commands.
+       *
        * @param[in] shell     Pointer to the shell object.
        * @param[in] cmd       Name of the command to removde.
        * @param[out] removed  Optional pointer to the command that was removed.
+       *
        * @return              A status value.
        * @retval AOS_SUCCESS  The command was removed successfully.
        * @retval AOS_ERROR    The command name was not found.
        */
       aos_status_t aosShellRemoveCommand(aos_shell_t *shell, char *cmd, aos_shellcommand_t **removed)
+      {
         aosDbgCheck(shell != NULL);
         aosDbgCheck(cmd != NULL && strlen(cmd) > 0);
         aos_shellcommand_t* prev = NULL;
         aos_shellcommand_t** curr = &(shell->commands);
         // iterate through the list and seach for the specified command name
         while (curr != NULL) {
           const int cmpval = strcmp((*curr)->name, cmd);
           // iterate through the list as long as the command names are 'smaller'
           if (cmpval < 0) {
             prev = *curr;
             curr = &((*curr)->next);
             continue;
+          }
           // remove the command when found
           else if (cmpval == 0) {
             // special case: the first command matches
             if (prev == NULL) {
               shell->commands = (*curr)->next;
             } else {
               prev->next = (*curr)->next;
+            }
             (*curr)->next = NULL;
             // set the optional output argument
             if (removed != NULL) {
               *removed = *curr;
+            }
             return AOS_SUCCESS;
+          }
           // break the loop if the command names are 'larger'
           else /* if (cmpval > 0) */ {
             break;
+          }
+        }
         // if the command was not found, return an error
         return AOS_ERROR;
+      }
       /**
        * @brief   Count the number of commands assigned to the shell.
+       *
        * @param[in] shell   The shell to count the commands for.
+       *
        * @return  The number of commands associated to the shell.
        */
       unsigned int aosShellCountCommands(aos_shell_t* shell)
+      {
         aosDbgCheck(shell != NULL);
         unsigned int count = 0;
         aos_shellcommand_t* cmd = shell->commands;
         while (cmd != NULL) {
           ++count;
           cmd = cmd->next;
+        }
         return count;
+      }
       /**
        * @brief   Add a channel to a AosShellStream.
+       *
        * @param[in] stream    The AosShellStream to extend.
        * @param[in] channel   The channel to be added to the stream.
        */
       void aosShellStreamAddChannel(AosShellStream* stream, AosShellChannel* channel)
+      {
         aosDbgCheck(stream != NULL);
         aosDbgCheck(channel != NULL && channel->asyncchannel != NULL && channel->next == NULL && (channel->flags & AOS_SHELLCHANNEL_ATTACHED) == 0);
         // prepend the new channel
         chSysLock();
         channel->flags |= AOS_SHELLCHANNEL_ATTACHED;
         channel->next = stream->channel;
         stream->channel = channel;
         chSysUnlock();
         return;
+      }
       /**
        * @brief   Remove a channel from an AosShellStream.
+       *
        * @param[in] stream    The AosShellStream to modify.
        * @param[in] channel   The channel to remove.
+       *
        * @return              A status value.
        * @retval AOS_SUCCESS  The channel was removed successfully.
        * @retval AOS_ERROR    The specified channel was not found to be associated with the shell.
        */
       aos_status_t aosShellStreamRemoveChannel(AosShellStream* stream, AosShellChannel* channel)
+      {
         aosDbgCheck(stream != NULL);
         aosDbgCheck(channel != NULL && channel->asyncchannel != NULL && channel->flags & AOS_SHELLCHANNEL_ATTACHED);
         // local varibales
         AosShellChannel* prev = NULL;
         AosShellChannel* curr = stream->channel;
         // iterate through the list and search for the specified channel
         while (curr != NULL) {
           // if the channel was found
           if (curr == channel) {
             chSysLock();
             // special case: the first channel matches (prev is NULL)
             if (prev == NULL) {
               stream->channel = curr->next;
             } else {
               prev->next = channel->next;
+            }
             curr->next = NULL;
             curr->flags &= ~AOS_SHELLCHANNEL_ATTACHED;
             chSysUnlock();
             return AOS_SUCCESS;
+          }
+        }
         // if the channel was not found, return an error
         return AOS_ERROR;
+      }
       /**
        * @brief   Enable a AosShellChannel as input.
+       *
        * @param[in] channel   The channel to enable as input.
        */
       void aosShellChannelInputEnable(AosShellChannel* channel)
+      {
         aosDbgCheck(channel != NULL && channel->asyncchannel != NULL);
         chSysLock();
         channel->listener.wflags |= CHN_INPUT_AVAILABLE;
         channel->flags |= AOS_SHELLCHANNEL_INPUT_ENABLED;
         chSysUnlock();
         return;
+      }
       /**
        * @brief   Disable a AosShellChannel as input.
+       *
        * @param[in] channel   The channel to disable as input.
        */
       void aosShellChannelInputDisable( AosShellChannel* channel)
+      {
         aosDbgCheck(channel != NULL && channel->asyncchannel != NULL);
         chSysLock();
         channel->listener.wflags &= ~CHN_INPUT_AVAILABLE;
         channel->flags &= ~AOS_SHELLCHANNEL_INPUT_ENABLED;
         chSysUnlock();
         return;
+      }
       /**
        * @brief   Enable a AosShellChannel as output.
+       *
        * @param[in] channel   The channel to enable as output.
        */
       void aosShellChannelOutputEnable(AosShellChannel* channel)
+      {
         aosDbgCheck(channel != NULL && channel->asyncchannel != NULL);
         channel->flags |= AOS_SHELLCHANNEL_OUTPUT_ENABLED;
         return;
+      }
       /**
        * @brief   Disable a AosShellChannel as output.
+       *
        * @param[in] channel   The channel to disable as output.
        */
       void aosShellChannelOutputDisable(AosShellChannel* channel)
+      {
         aosDbgCheck(channel != NULL && channel->asyncchannel != NULL);
         channel->flags &= ~AOS_SHELLCHANNEL_OUTPUT_ENABLED;
         return;
+      }
       /**
        * @brief   Thread main function.
+       *
        * @param[in] aosShellThread    Name of the function;
        * @param[in] shell             Pointer to the shell object.
        */
       void aosShellThread(void* shell)
+      {
         aosDbgCheck(shell != NULL);
         aosDbgCheck(((aos_shell_t*)shell)->input.nentries > 0);
         // local variables
         eventmask_t eventmask;
         eventflags_t eventflags;
         AosShellChannel* channel;
         runtimedata_t rdata;
         char* args[((aos_shell_t*)shell)->input.nargs];
         size_t nargs = 0;
         aos_shellcommand_t* cmd;
         // initialize variables and buffers
         rdata.input.length = 0;
         rdata.input.cursorpos = 0;
         memset(rdata.input.escseq, '\0', AOS_SHELL_ESCSEQUENCE_LENGTH * sizeof(char));
         rdata.buffer.current = 0;
         rdata.buffer.selected = (((aos_shell_t*)shell)->input.nentries > 1) ? 1 : 0;
         rdata.buffer.edited = 0;
         rdata.lastaction = ACTION_NONE;
         for (size_t arg = 0; arg < ((aos_shell_t*)shell)->input.nargs; ++arg) {
           args[arg] = NULL;
+        }
         memset(_getCurrentEntry((aos_shell_t*)shell, &rdata), '\0', ((aos_shell_t*)shell)->input.linewidth * sizeof(char));
         // register OS related events
         chEvtRegisterMask(&aos.events.os, &(((aos_shell_t*)shell)->osEventListener), EVENTMASK_OS);
         // register events to all input channels
         for (channel = ((aos_shell_t*)shell)->stream.channel; channel != NULL; channel = channel->next) {
           chEvtRegisterMaskWithFlags(&(channel->asyncchannel->event), &(channel->listener), EVENTMASK_INPUT, channel->listener.wflags);
+        }
         // fire start event
         chEvtBroadcastFlags(&(((aos_shell_t*)shell)->eventSource), AOS_SHELL_EVTFLAG_START);
         // print the prompt for the first time
         _printPrompt((aos_shell_t*)shell);
         // enter thread loop
         while (!chThdShouldTerminateX()) {
           // wait for event and handle it accordingly
           eventmask = chEvtWaitOne(ALL_EVENTS);
           // handle event
           switch (eventmask) {
             // OS related events
             case EVENTMASK_OS:
+            {
               eventflags = chEvtGetAndClearFlags(&((aos_shell_t*)shell)->osEventListener);
               // handle shutdown/restart events
               if (eventflags & AOS_SYSTEM_EVENTFLAGS_SHUTDOWN_MASK) {
                 chThdTerminate(((aos_shell_t*)shell)->thread);
               } else {
                 // print an error message
                 chprintf((BaseSequentialStream*)&((aos_shell_t*)shell)->stream, "\nERROR: unknown OS event received (0x%08X)\n", eventflags);
+              }
               break;
+            }
             // input events
             case EVENTMASK_INPUT:
+            {
               // check and handle all channels
               channel = ((aos_shell_t*)shell)->stream.channel;
               while (channel != NULL) {
                 eventflags = chEvtGetAndClearFlags(&channel->listener);
                 // if there is new input and a command shall be executed
                 if (eventflags & CHN_INPUT_AVAILABLE) {
                   _readChannel(shell, &rdata, channel);
                   // if an execution request was detected
                   if (rdata.lastaction == ACTION_EXECUTE) {
                     streamPut(&((aos_shell_t*)shell)->stream, '\n');
                     char* line = _getVisualisedEntry((aos_shell_t*)shell, &rdata);
                     // skip, if there is nothing to be executed
                     if (line) {
                       // parse arguments
                       nargs = _parseArguments(shell, line, args);
                       // check number of arguments found
                       if (nargs > ((aos_shell_t*)shell)->input.nargs) {
                         chprintf((BaseSequentialStream*)&((aos_shell_t*)shell)->stream, "\ttoo many arguments\n");
                       } else if (nargs > 0) {
                         // search command list for arg[0] and execute callback
                         cmd = ((aos_shell_t*)shell)->commands;
                         while (cmd != NULL) {
                           // if the requested command has been found
                           if (strcmp(args[0], cmd->name) == 0) {
                             ((aos_shell_t*)shell)->execstatus.command = cmd;
                             chEvtBroadcastFlags(&((aos_shell_t*)shell)->eventSource, AOS_SHELL_EVTFLAG_EXECUTE);
                             ((aos_shell_t*)shell)->execstatus.retval = cmd->callback((BaseSequentialStream*)&((aos_shell_t*)shell)->stream, (int)nargs, args);
                             chEvtBroadcastFlags(&((aos_shell_t*)shell)->eventSource, AOS_SHELL_EVTFLAG_DONE);
                             // notify user if execution of the command was not successful
                             if (((aos_shell_t*)shell)->execstatus.retval != 0) {
                               chprintf((BaseSequentialStream*)&((aos_shell_t*)shell)->stream, "command returned exit status %d\n", ((aos_shell_t*)shell)->execstatus.retval);
+                            }
                             break;
+                          }
                           // keep searching
                           else {
                             cmd = cmd->next;
+                          }
                         } /* end of while */
                         // if no matching command was found, print a message
                         if (cmd == NULL) {
                           chprintf((BaseSequentialStream*)&((aos_shell_t*)shell)->stream, "\tcommand '%s' not found\n", args[0]);
+                        }
+                      }
                       // restore spaces in the current entry, which have been modified to NUL bytes due to argument parsing
                       _restoreWhitespace(line, rdata.input.length);
                       // update internat variables
+                      {
                         rdata.input.length = 0;
                         rdata.input.cursorpos = 0;
                         rdata.buffer.edited = 0;
                         // if the input buffer can hold historic entries
                         if (((aos_shell_t*)shell)->input.nentries > 1) {
                           // iterate in the history only if
                           // there was some valid input and
                           // the user did not execute the exact previous command again
                           if (nargs > 0 &&
                               strcmp(line, _getRelativeEntry((aos_shell_t*)shell, &rdata, 1)) != 0) {
                             rdata.buffer.current = (rdata.buffer.current + 1) % ((aos_shell_t*)shell)->input.nentries;
+                          }
                           // clear and select next (now current) entry
                           memset(_getCurrentEntry((aos_shell_t*)shell, &rdata), '\0', ((aos_shell_t*)shell)->input.linewidth * sizeof(char));
                           rdata.buffer.selected = 1;
+                        }
                         // if there is only a single entry in the input buffer
                         else {
                           // do not clear/reset the entry, but start off with a cleared preview
                           rdata.buffer.selected = 0;
+                        }
+                      }
+                    }
                     // print a new prompt
                     if (!chThdShouldTerminateX()) {
                       _printPrompt((aos_shell_t*)shell);
+                    }
+                  }
+                }
                 // iterate to next channel
                 channel = channel->next;
+              }
               break;
+            }
             // other events
             default:
+            {
               // print an error message
               chprintf((BaseSequentialStream*)&((aos_shell_t*)shell)->stream, "\nSHELL: ERROR: unknown event received (0x%08X)\n", eventmask);
               break;
+            }
           } /* end of switch */
         } /* end of while */
         // fire event and exit the thread
         chSysLock();
         chEvtBroadcastFlagsI(&(((aos_shell_t*)shell)->eventSource), AOS_SHELL_EVTFLAG_EXIT);
         chThdExitS(MSG_OK);
         // no chSysUnlock() required since the thread has been terminated an all waiting threads have been woken up
+      }
       #endif /* (AMIROOS_CFG_SHELL_ENABLE == true) */
       /** @} */