/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..2018  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 <aos_shell.h>
       #if (AMIROOS_CFG_SHELL_ENABLE == true)
       #include <aos_debug.h>
       #include <aos_time.h>
       #include <aos_system.h>
       #include <string.h>
       /**
        * @brief   Event mask to be set on OS related events.
        */
       #define AOS_SHELL_EVENTMASK_OS                  EVENT_MASK(0)
       /**
        * @brief   Event mask to be set on a input event.
        */
       #define AOS_SHELL_EVENTMASK_INPUT               EVENT_MASK(1)
       /**
        * @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;
+      }
       static const struct AosShellChannelVMT _channelvmt = {
         (size_t) 0,
         _channelwrite,
         _channelread,
         _channelput,
         _channelget,
         _channelputt,
         _channelgett,
         _channelwritet,
         _channelreadt,
         _channelctl,
       };
       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;
+      }
       static size_t _stremread(void *instance, uint8_t *bp, size_t n)
+      {
         (void)instance;
         (void)bp;
         (void)n;
         return 0;
+      }
       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;
+      }
       static msg_t _streamget(void *instance)
+      {
         (void)instance;
         return 0;
+      }
       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_ESCAPE,       /**< escape key */
         KEY_BACKSPACE,    /**< backspace key */
         KEY_INSERT,       /**< insert key */
         KEY_DELETE,       /**< delete key */
         KEY_HOME,         /**< home key */
         KEY_END,          /**< end key */
         KEY_PAGE_UP,      /**< page up key */
         KEY_PAGE_DOWN,    /**< page down key */
         KEY_ARROW_UP,     /**< arrow up key */
         KEY_ARROW_DOWN,   /**< arrow down key */
         KEY_ARROW_LEFT,   /**< arrow left key */
         KEY_ARROW_RIGHT,  /**< arrow right 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   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));
+          }
           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);
+          }
           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
+       *
        * @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
         bool ambiguous = false;
         int cmp = 0;
         // TAB
         /* not supported yet; use "\x09" instead */
         // BACKSPACE
         /* not supported yet; use "\x08" instead */
         // ESCAPE
         cmp = strcmp(seq, "\x1B");
         if (cmp == 0) {
           return KEY_ESCAPE;
         } else {
           ambiguous |= (cmp < 0);
+        }
         // INSERT
         cmp = strcmp(seq, "\x1B\x5B\x32\x7E");
         if (cmp == 0) {
           return KEY_INSERT;
         } else {
           ambiguous |= (cmp < 0);
+        }
         // DELETE
         cmp = strcmp(seq, "\x1B\x5B\x33\x7E");
         if (cmp == 0) {
           return KEY_DELETE;
         } else {
           ambiguous |= (cmp < 0);
+        }
         // HOME
         cmp = strcmp(seq, "\x1B\x4F\x48");
         if (cmp == 0) {
           return KEY_HOME;
         } else {
           ambiguous |= (cmp < 0);
+        }
         // END
         cmp = strcmp(seq, "\x1B\x4F\x46");
         if (cmp == 0) {
           return KEY_END;
         } else {
           ambiguous |= (cmp < 0);
+        }
         // PAGE UP
         cmp = strcmp(seq, "\x1B\x5B\x35\x7E");
         if (cmp == 0) {
           return KEY_PAGE_UP;
         } else {
           ambiguous |= (cmp < 0);
+        }
         // PAGE DOWN
         cmp = strcmp(seq, "\x1B\x5B\x36\x7E");
         if (cmp == 0) {
           return KEY_PAGE_DOWN;
         } else {
           ambiguous |= (cmp < 0);
+        }
         // ARROW UP
         cmp = strcmp(seq, "\x1B\x5B\x41");
         if (cmp == 0) {
           return KEY_ARROW_UP;
         } else {
           ambiguous |= (cmp < 0);
+        }
         // ARROW DOWN
         cmp = strcmp(seq, "\x1B\x5B\x42");
         if (cmp == 0) {
           return KEY_ARROW_DOWN;
         } else {
           ambiguous |= (cmp < 0);
+        }
         // ARROW LEFT
         cmp = strcmp(seq, "\x1B\x5B\x44");
         if (cmp == 0) {
           return KEY_ARROW_LEFT;
         } else {
           ambiguous |= (cmp < 0);
+        }
         // ARROW RIGHT
         cmp = strcmp(seq, "\x1B\x5B\x43");
         if (cmp == 0) {
           return KEY_ARROW_RIGHT;
         } else {
           ambiguous |= (cmp < 0);
+        }
         return ambiguous ? KEY_AMBIGUOUS : KEY_UNKNOWN;
+      }
       /**
        * @brief   Move the cursor in the terminal
+       *
        * @param[in] shell   Pointer to the shell object.
        * @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 size_t from, const size_t to)
+      {
         aosDbgCheck(shell != NULL);
         // 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, shell->line[pos]);
           ++pos;
+        }
         return (int)pos - (int)from;
+      }
       /**
        * @brief   Print content of the shell line
+       *
        * @param[in] shell   Pointer to the shell object.
        * @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 inline size_t _printLine(aos_shell_t* shell, const size_t from, const size_t to)
+      {
         aosDbgCheck(shell != NULL);
         // local variables
         size_t cnt;
         for (cnt = 0; from + cnt < to; ++cnt) {
           streamPut(&shell->stream, shell->line[from + cnt]);
+        }
         return cnt;
+      }
       /**
        * @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(const 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]);
+      }
       static aos_status_t _readChannel(aos_shell_t* shell, AosShellChannel* channel, size_t* n)
+      {
         aosDbgCheck(shell != NULL);
         aosDbgCheck(channel != NULL);
         aosDbgCheck(n != NULL);
         // local variables
         aos_shellaction_t action = AOS_SHELL_ACTION_NONE;
         char c;
         special_key_t key;
         // initialize output variables
         *n = 0;
         // read character by character from the channel
         while (chnReadTimeout(channel, (uint8_t*)&c, 1, TIME_IMMEDIATE)) {
           key = KEY_UNKNOWN;
           // parse escape sequence
           if (shell->inputdata.escp > 0) {
             shell->inputdata.escseq[shell->inputdata.escp] = c;
             ++shell->inputdata.escp;
             key = _interpreteEscapeSequence(shell->inputdata.escseq);
             if (key == KEY_AMBIGUOUS) {
               // read next byte to resolve ambiguity
               continue;
             } else {
               /*
                * If the escape sequence could either be parsed sucessfully
                * or there is no match (KEY_UNKNOWN),
                * reset the sequence variable and interprete key/character
                */
               shell->inputdata.escp = 0;
               memset(shell->inputdata.escseq, '\0', sizeof(shell->inputdata.escseq)*sizeof(shell->inputdata.escseq[0]));
+            }
+          }
           /* interprete keys or character */
+          {
             // default
             action = AOS_SHELL_ACTION_NONE;
             // printable character
             if (key == KEY_UNKNOWN && c >= '\x20' && c <= '\x7E') {
               action = AOS_SHELL_ACTION_READCHAR;
+            }
             // tab key or character
             else if (key == KEY_TAB || c == '\x09') {
               /*
                * pressing tab once applies auto fill
                * pressing tab a second time prints suggestions
                */
               if (shell->inputdata.lastaction == AOS_SHELL_ACTION_AUTOFILL || shell->inputdata.lastaction == AOS_SHELL_ACTION_SUGGEST) {
                 action = AOS_SHELL_ACTION_SUGGEST;
               } else {
                 action = AOS_SHELL_ACTION_AUTOFILL;
+              }
+            }
             // INS key
             else if (key == KEY_INSERT) {
               action = AOS_SHELL_ACTION_INSERTTOGGLE;
+            }
             // DEL key or character
             else if (key == KEY_DELETE || c == '\x7F') {
               // ignore if cursor is at very right
               if (shell->inputdata.cursorpos < shell->inputdata.lineend) {
                 action = AOS_SHELL_ACTION_DELETEFORWARD;
+              }
+            }
             // backspace key or character
             else if (key == KEY_BACKSPACE || c == '\x08') {
               // ignore if cursor is at very left
               if (shell->inputdata.cursorpos > 0) {
                 action = AOS_SHELL_ACTION_DELETEBACKWARD;
+              }
+            }
             // 'page up' of 'arrow up' key
             else if (key == KEY_PAGE_UP || key == KEY_ARROW_UP) {
               // ignore if there was some input
               if (shell->inputdata.noinput) {
                 action = AOS_SHELL_ACTION_RECALLLAST;
+              }
+            }
             // 'page down' key, 'arrow done' key, 'end of test' character or 'end of transmission' character
             else if (key == KEY_PAGE_DOWN || key == KEY_ARROW_DOWN || c == '\x03' || c == '\x03') {
               // ignore if line is empty
               if (shell->inputdata.lineend > 0) {
                 action = AOS_SHELL_ACTION_CLEAR;
+              }
+            }
             // 'home' key
             else if (key == KEY_HOME) {
               // ignore if cursor is very left
               if (shell->inputdata.cursorpos > 0) {
                 action = AOS_SHELL_ACTION_CURSOR2START;
+              }
+            }
             // 'end' key
             else if (key == KEY_END) {
               // ignore if cursos is very right
               if (shell->inputdata.cursorpos < shell->inputdata.lineend) {
                 action = AOS_SHELL_ACTION_CURSOR2END;
+              }
+            }
             // 'arrow left' key
             else if (key == KEY_ARROW_LEFT) {
               // ignore if cursor is very left
               if (shell->inputdata.cursorpos > 0) {
                 action = AOS_SHELL_ACTION_CURSORLEFT;
+              }
+            }
             // 'arrow right' key
             else if (key == KEY_ARROW_RIGHT) {
               // irgnore if cursor is very right
               if (shell->inputdata.cursorpos < shell->inputdata.lineend) {
                 action = AOS_SHELL_ACTION_CURSORRIGHT;
+              }
+            }
             // carriage return ('\r') or line feed ('\n') character
             else if (c == '\x0D' || c == '\x0A') {
               action = AOS_SHELL_ACTION_EXECUTE;
+            }
             // ESC key or [ESCAPE] character
             else if (key == KEY_ESCAPE || c == '\x1B') {
               action = AOS_SHELL_ACTION_ESCSTART;
+            }
+          }
           /* handle function */
           switch (action) {
             case AOS_SHELL_ACTION_READCHAR:
+            {
               // line is full
               if (shell->inputdata.lineend + 1 >= shell->linesize) {
                 _moveCursor(shell, shell->inputdata.cursorpos, shell->inputdata.lineend);
                 chprintf((BaseSequentialStream*)&shell->stream, "\n\tmaximum line width reached\n");
                 _printPrompt(shell);
                 _printLine(shell, 0, shell->inputdata.lineend);
                 _moveCursor(shell, shell->inputdata.lineend, shell->inputdata.cursorpos);
+              }
               // read character
               else {
                 // clear old line content on first input
                 if (shell->inputdata.noinput) {
                   memset(shell->line, '\0', shell->linesize);
                   shell->inputdata.noinput = false;
+                }
                 // overwrite content
                 if (shell->config & AOS_SHELL_CONFIG_INPUT_OVERWRITE) {
                   shell->line[shell->inputdata.cursorpos] = c;
                   ++shell->inputdata.cursorpos;
                   shell->inputdata.lineend = (shell->inputdata.cursorpos > shell->inputdata.lineend) ? shell->inputdata.cursorpos : shell->inputdata.lineend;
                   streamPut(&shell->stream, (uint8_t)c);
+                }
                 // insert character
                 else {
                   memmove(&(shell->line[shell->inputdata.cursorpos+1]), &(shell->line[shell->inputdata.cursorpos]), shell->inputdata.lineend - shell->inputdata.cursorpos);
                   shell->line[shell->inputdata.cursorpos] = c;
                   ++shell->inputdata.lineend;
                   _printLine(shell, shell->inputdata.cursorpos, shell->inputdata.lineend);
                   ++shell->inputdata.cursorpos;
                   _moveCursor(shell, shell->inputdata.lineend, shell->inputdata.cursorpos);
+                }
+              }
               break;
+            }
             case AOS_SHELL_ACTION_AUTOFILL:
+            {
               const char* fill = shell->line;
               size_t cmatch = shell->inputdata.cursorpos;
               charmatch_t matchlevel = CHAR_MATCH_NOT;
               size_t n;
               // 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) ?
                                   (n - cmatch) :
                                   (cmd->name[n] != '\0') ?
                                     strlen(cmd->name) - n :
 ;
                 // if an exact match was found
                 if (cmatch + cmp == shell->inputdata.cursorpos) {
                   cmatch = shell->inputdata.cursorpos;
                   fill = cmd->name;
                   // break the loop only if there are no case mismatches with the input
                   n = shell->inputdata.cursorpos;
                   _strccmp(fill, shell->line, false, &n, &mlvl);
                   if (mlvl == CHAR_MATCH_CASE) {
                     break;
+                  }
+                }
                 // if a not exact match was found
                 else if (cmatch + cmp > shell->inputdata.cursorpos) {
                   // if this is the first one
                   if (fill == shell->line) {
                     cmatch += cmp;
                     fill = cmd->name;
+                  }
                   // if this is a worse one
                   else if ((cmp < 0) || (cmp == 0 && mlvl == CHAR_MATCH_CASE)) {
                     cmatch += cmp;
+                  }
+                }
                 // non matching commands are ignored
                 else {}
+              }
               // evaluate if there are case mismatches
               n = cmatch;
               _strccmp(shell->line, fill, shell->config & AOS_SHELL_CONFIG_MATCH_CASE, &n, &matchlevel);
               // print the auto fill if any
               if (cmatch > shell->inputdata.cursorpos || (cmatch == shell->inputdata.cursorpos && matchlevel == CHAR_MATCH_NCASE)) {
                 shell->inputdata.noinput = false;
                 // limit auto fill so it will not overflow the line width
                 if (shell->inputdata.lineend + (cmatch - shell->inputdata.cursorpos) > shell->linesize) {
                   cmatch = shell->linesize - shell->inputdata.lineend + shell->inputdata.cursorpos;
+                }
                 // move trailing memory further in the line
                 memmove(&(shell->line[cmatch]), &(shell->line[shell->inputdata.cursorpos]), shell->inputdata.lineend - shell->inputdata.cursorpos);
                 shell->inputdata.lineend += cmatch - shell->inputdata.cursorpos;
                 // if there was no incorrect case when matching
                 if (matchlevel == CHAR_MATCH_CASE) {
                   // insert fill command name to line
                   memcpy(&(shell->line[shell->inputdata.cursorpos]), &(fill[shell->inputdata.cursorpos]), cmatch - shell->inputdata.cursorpos);
                   // print the output
                   _printLine(shell, shell->inputdata.cursorpos, shell->inputdata.lineend);
                 } else {
                   // overwrite line with fill command name
                   memcpy(shell->line, fill, cmatch);
                   // reprint the whole line
                   _moveCursor(shell, shell->inputdata.cursorpos, 0);
                   _printLine(shell, 0, shell->inputdata.lineend);
+                }
                 // move cursor to the end of the matching sequence
                 shell->inputdata.cursorpos = cmatch;
                 _moveCursor(shell, shell->inputdata.lineend, shell->inputdata.cursorpos);
+              }
               break;
+            }
             case AOS_SHELL_ACTION_SUGGEST:
+            {
               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, excpet if cursorpos=0
                 size_t i = shell->inputdata.cursorpos;
                 if (shell->inputdata.cursorpos > 0) {
                   _strccmp(shell->line, cmd->name, true, &i, NULL);
+                }
                 const int cmp = (i < shell->inputdata.cursorpos) ?
                                   (i - shell->inputdata.cursorpos) :
                                   (cmd->name[i] != '\0') ?
                                     strlen(cmd->name) - i :
 ;
                 // if a match was found
                 if (cmp > 0) {
                   // if this is the first one
                   if (matches == 0) {
                     _moveCursor(shell, shell->inputdata.cursorpos, shell->inputdata.lineend);
                     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);
                 _printLine(shell, 0, shell->inputdata.lineend);
                 _moveCursor(shell, shell->inputdata.lineend, shell->inputdata.cursorpos);
                 shell->inputdata.noinput = false;
+              }
               break;
+            }
             case AOS_SHELL_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 AOS_SHELL_ACTION_DELETEFORWARD:
+            {
               --shell->inputdata.lineend;
               memmove(&(shell->line[shell->inputdata.cursorpos]), &(shell->line[shell->inputdata.cursorpos+1]), shell->inputdata.lineend - shell->inputdata.cursorpos);
               _printLine(shell, shell->inputdata.cursorpos, shell->inputdata.lineend);
               streamPut(&shell->stream, ' ');
               _moveCursor(shell, shell->inputdata.lineend + 1, shell->inputdata.cursorpos);
               break;
+            }
             case AOS_SHELL_ACTION_DELETEBACKWARD:
+            {
               --shell->inputdata.cursorpos;
               memmove(&(shell->line[shell->inputdata.cursorpos]), &(shell->line[shell->inputdata.cursorpos+1]), shell->inputdata.lineend - shell->inputdata.cursorpos);
               --shell->inputdata.lineend;
               shell->line[shell->inputdata.lineend] = '\0';
               _moveCursor(shell, shell->inputdata.cursorpos + 1, shell->inputdata.cursorpos);
               _printLine(shell, shell->inputdata.cursorpos, shell->inputdata.lineend);
               streamPut(&shell->stream, ' ');
               _moveCursor(shell, shell->inputdata.lineend+1, shell->inputdata.cursorpos);
               break;
+            }
             case AOS_SHELL_ACTION_RECALLLAST:
+            {
               // replace any intermediate NUL bytes with spaces
               shell->inputdata.lineend = 0;
               size_t nul_start = 0;
               size_t nul_end = 0;
               // search line for a NUL byte
               while (nul_start < shell->linesize) {
                 if (shell->line[nul_start] == '\0') {
                   nul_end = nul_start + 1;
                   // keep searcjing for a byte that is not NUL
                   while (nul_end < shell->linesize) {
                     if (shell->line[nul_end] != '\0') {
                       // an intermediate NUL sequence was found
                       memset(&(shell->line[nul_start]), ' ', nul_end - nul_start);
                       shell->inputdata.lineend = nul_end + 1;
                       break;
                     } else {
                       ++nul_end;
+                    }
+                  }
                   nul_start = nul_end + 1;
                 } else {
                   ++shell->inputdata.lineend;
                   ++nul_start;
+                }
+              }
               shell->inputdata.cursorpos = shell->inputdata.lineend;
               // print the line
               shell->inputdata.noinput = _printLine(shell, 0, shell->inputdata.lineend) == 0;
               break;
+            }
             case AOS_SHELL_ACTION_CLEAR:
+            {
               // clear output
               _moveCursor(shell, shell->inputdata.cursorpos, 0);
               for (shell->inputdata.cursorpos = 0; shell->inputdata.cursorpos < shell->inputdata.lineend; ++shell->inputdata.cursorpos) {
                 streamPut(&shell->stream, ' ');
+              }
               _moveCursor(shell, shell->inputdata.lineend, 0);
               shell->inputdata.cursorpos = 0;
               shell->inputdata.lineend = 0;
               shell->inputdata.noinput = true;
               break;
+            }
             case AOS_SHELL_ACTION_CURSOR2START:
+            {
               _moveCursor(shell, shell->inputdata.cursorpos, 0);
               shell->inputdata.cursorpos = 0;
               break;
+            }
             case AOS_SHELL_ACTION_CURSOR2END:
+            {
               _moveCursor(shell, shell->inputdata.cursorpos, shell->inputdata.lineend);
               shell->inputdata.cursorpos = shell->inputdata.lineend;
               break;
+            }
             case AOS_SHELL_ACTION_CURSORLEFT:
+            {
               _moveCursor(shell, shell->inputdata.cursorpos, shell->inputdata.cursorpos-1);
               --shell->inputdata.cursorpos;
               break;
+            }
             case AOS_SHELL_ACTION_CURSORRIGHT:
+            {
               _moveCursor(shell, shell->inputdata.cursorpos, shell->inputdata.cursorpos+1);
               ++shell->inputdata.cursorpos;
               break;
+            }
             case AOS_SHELL_ACTION_EXECUTE:
+            {
               streamPut(&shell->stream, '\n');
               // set the number of read bytes and return
               if (!shell->inputdata.noinput) {
                 *n = shell->linesize - shell->inputdata.lineend;
                 // fill the remainder of the line with NUL bytes
                 memset(&(shell->line[shell->inputdata.lineend]), '\0', *n);
                 // reset static variables
                 shell->inputdata.noinput = true;
+              }
               return AOS_SUCCESS;
               break;
+            }
             case AOS_SHELL_ACTION_ESCSTART:
+            {
               shell->inputdata.escseq[0] = c;
               ++shell->inputdata.escp;
               break;
+            }
             case AOS_SHELL_ACTION_NONE:
             default:
+            {
               // do nothing (ignore input) and read next byte
               continue;
               break;
+            }
           } /* end of switch */
           shell->inputdata.lastaction = action;
         } /* end of while */
         // no more data could be read from the channel
         return AOS_WARNING;
+      }
       /**
        * @brief   Parses the content of the input buffer (line) to separate arguments.
+       *
        * @param[in] shell   Pointer to the shell object.
+       *
        * @return            Number of arguments found.
        */
       static size_t _parseArguments(aos_shell_t* shell)
+      {
         aosDbgCheck(shell != NULL);
         /*
          * States for a very small FSM.
          */
         typedef enum {
           START,
           SPACE,
           TEXT,
           END,
         } state_t;
         // local variables
         state_t state = START;
         size_t arg = 0;
         // iterate through the line
         for (char* c = shell->line; c < shell->line + shell->linesize; ++c) {
           // terminate at first NUL byte
           if (*c == '\0') {
             state = END;
             break;
+          }
           // spaces become NUL bytes
           else if (*c == ' ') {
             *c = '\0';
             state = SPACE;
+          }
           // handle non-NUL bytes
           else {
             switch (state) {
               case START:
               case SPACE:
                 // ignore too many arguments
                 if (arg < shell->arglistsize) {
                   shell->arglist[arg] = c;
+                }
                 ++arg;
                 break;
               case TEXT:
               case END:
               default:
                 break;
+            }
             state = TEXT;
+          }
+        }
         // set all remaining argument pointers to NULL
         for (size_t a = arg; a < shell->arglistsize; ++a) {
           shell->arglist[a] = NULL;
+        }
         return arg;
+      }
       /**
        * @brief   Initializes a shell object with the specified parameters.
+       *
        * @param[in] shell         Pointer to the shell object.
        * @param[in] stream        I/O stream to use.
        * @param[in] prompt        Prompt line to print (NULL = use default prompt).
        * @param[in] line          Pointer to the input buffer.
        * @param[in] linesize      Size of the input buffer.
        * @param[in] arglist       Pointer to the argument buffer.
        * @param[in] arglistsize   Size of te argument buffer.
        */
       void aosShellInit(aos_shell_t* shell, event_source_t* oseventsource,  const char* prompt, char* line, size_t linesize, char** arglist, size_t arglistsize)
+      {
         aosDbgCheck(shell != NULL);
         aosDbgCheck(oseventsource != NULL);
         aosDbgCheck(line != NULL);
         aosDbgCheck(arglist != NULL);
         // set parameters
         shell->thread = NULL;
         chEvtObjectInit(&shell->eventSource);
         shell->os.eventSource = oseventsource;
         aosShellStreamInit(&shell->stream);
         shell->prompt = prompt;
         shell->commands = NULL;
         shell->execstatus.command = NULL;
         shell->execstatus.retval = 0;
         shell->line = line;
         shell->linesize = linesize;
         shell->inputdata.lastaction = AOS_SHELL_ACTION_NONE;
         shell->inputdata.escp = 0;
         memset(shell->inputdata.escseq, '\0', sizeof(shell->inputdata.escseq)*sizeof(shell->inputdata.escseq[0]));
         shell->inputdata.cursorpos = 0;
         shell->inputdata.lineend = 0;
         shell->inputdata.noinput = true;
         shell->arglist = arglist;
         shell->arglistsize = arglistsize;
         shell->config = 0x00;
         // initialize arrays
         memset(shell->line, '\0', shell->linesize);
         for (size_t a = 0; a < shell->arglistsize; ++a) {
           shell->arglist[a] = NULL;
+        }
         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 AosSheööChannel 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 AosSheööChannel 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 AosSheööChannel 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 AosSheööChannel 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);
         // local variables
         eventmask_t eventmask;
         eventflags_t eventflags;
         AosShellChannel* channel;
         aos_status_t readeval;
         size_t nchars = 0;
         size_t nargs = 0;
         aos_shellcommand_t* cmd;
         // register OS related events
         chEvtRegisterMask(((aos_shell_t*)shell)->os.eventSource, &(((aos_shell_t*)shell)->os.eventListener), AOS_SHELL_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), AOS_SHELL_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 AOS_SHELL_EVENTMASK_OS:
+            {
               eventflags = chEvtGetAndClearFlags(&((aos_shell_t*)shell)->os.eventListener);
               // handle shutdown/restart events
               if (eventflags & AOS_SYSTEM_EVENTFLAGS_SHUTDOWN) {
                 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 AOS_SHELL_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
                 if (eventflags & CHN_INPUT_AVAILABLE) {
                   // read input from channel
                   readeval = _readChannel((aos_shell_t*)shell, channel, &nchars);
                   // parse input line to argument list only if the input shall be executed
                   nargs = (readeval == AOS_SUCCESS && nchars > 0) ? _parseArguments((aos_shell_t*)shell) : 0;
                   // check number of arguments
                   if (nargs > ((aos_shell_t*)shell)->arglistsize) {
                     // error too many arguments
                     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 (strcmp(((aos_shell_t*)shell)->arglist[0], cmd->name) == 0) {
                         ((aos_shell_t*)shell)->execstatus.command = cmd;
                         chEvtBroadcastFlags(&(((aos_shell_t*)shell)->eventSource), AOS_SHELL_EVTFLAG_EXEC);
                         ((aos_shell_t*)shell)->execstatus.retval = cmd->callback((BaseSequentialStream*)&((aos_shell_t*)shell)->stream, nargs, ((aos_shell_t*)shell)->arglist);
                         chEvtBroadcastFlags(&(((aos_shell_t*)shell)->eventSource), AOS_SHELL_EVTFLAG_DONE);
                         // notify if 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;
+                      }
                       cmd = cmd->next;
                     } /* end of while */
                     // if no matching command was found, print an error
                     if (cmd == NULL) {
                       chprintf((BaseSequentialStream*)&((aos_shell_t*)shell)->stream, "%s: command not found\n", ((aos_shell_t*)shell)->arglist[0]);
+                    }
+                  }
                   // reset some internal variables and eprint a new prompt
                   if (readeval == AOS_SUCCESS && !chThdShouldTerminateX()) {
                     ((aos_shell_t*)shell)->inputdata.cursorpos = 0;
                     ((aos_shell_t*)shell)->inputdata.lineend = 0;
                     _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 */
       /** @} */