text: /**
   * @file lv_text.c
   * 
   */
  
  /*********************
   *      INCLUDES
   *********************/
  #include "lv_txt.h"
  #include "../../lv_conf.h"
  #include "lv_math.h"
  
  /*********************
   *      DEFINES
   *********************/
  #define NO_BREAK_FOUND  UINT32_MAX
  
  /**********************
   *      TYPEDEFS
   **********************/
  
  /**********************
   *  STATIC PROTOTYPES
   **********************/
  static bool is_break_char(uint32_t letter);
  
  /**********************
   *  STATIC VARIABLES
   **********************/
  
  /**********************
   *      MACROS
   **********************/
  
  /**********************
   *   GLOBAL FUNCTIONS
   **********************/
  
  /**
   * Get size of a text
   * @param size_res pointer to a 'point_t' variable to store the result
   * @param text pointer to a text
   * @param font pinter to font of the text
   * @param letter_space letter space of the text
   * @param txt.line_space line space of the text
   * @param flags settings for the text from 'txt_flag_t' enum
   * @param max_width max with of the text (break the lines to fit this size) Set CORD_MAX to avoid line breaks
   */
  void lv_txt_get_size(lv_point_t * size_res, const char * text, const lv_font_t * font,
                      lv_coord_t letter_space, lv_coord_t line_space, lv_coord_t max_width, lv_txt_flag_t flag)
  {
  
      size_res->x = 0;
      size_res->y = 0;
  
      if(text == NULL) return;
      if(font == NULL) return;
  
      if(flag & LV_TXT_FLAG_EXPAND) max_width = LV_COORD_MAX;
  
      uint32_t line_start = 0;
      uint32_t new_line_start = 0;
      lv_coord_t act_line_length;
      uint8_t letter_height = lv_font_get_height(font);
  
      /*Calc. the height and longest line*/
      while (text[line_start] != '\0') {
          new_line_start += lv_txt_get_next_line(&text[line_start], font, letter_space, max_width, flag);
          size_res->y += letter_height ;
          size_res->y += line_space;
  
          /*Calculate the the longest line*/
          act_line_length = lv_txt_get_width(&text[line_start], new_line_start - line_start,
                                         font, letter_space, flag);
  
          size_res->x = LV_MATH_MAX(act_line_length, size_res->x);
          line_start = new_line_start;
      }
  
      if(line_start != 0 && (text[line_start - 1] == '\n' || text[line_start - 1] == '\r')) {
          size_res->y += letter_height + line_space;
      }
  
      /*Correction with the last line space or set the height manually if the text is empty*/
      if(size_res->y == 0) size_res->y = letter_height;
      else size_res->y -= line_space;
  
  }
  
  /**
   * Get the next line of text. Check line length and break chars too.
   * @param txt a '\0' terminated string
   * @param font pointer to a font
   * @param letter_space letter space
   * @param max_width max with of the text (break the lines to fit this size) Set CORD_MAX to avoid line breaks
   * @param flags settings for the text from 'txt_flag_type' enum
   * @return the index of the first char of the new line (in byte index not letter index. With UTF-8 they are different)
   */
  uint16_t lv_txt_get_next_line(const char * txt, const lv_font_t * font,
                             lv_coord_t letter_space, lv_coord_t max_width, lv_txt_flag_t flag)
  {
      if(txt == NULL) return 0;
      if(font == NULL) return 0;
  
      if(flag & LV_TXT_FLAG_EXPAND) max_width = LV_COORD_MAX;
  
      uint32_t i = 0;
      lv_coord_t cur_w = 0;
      uint32_t last_break = NO_BREAK_FOUND;
      lv_txt_cmd_state_t cmd_state = LV_TXT_CMD_STATE_WAIT;
      uint32_t letter = 0;
  
      while(txt[i] != '\0') {
          letter = lv_txt_utf8_next(txt, &i);
  
          /*Handle the recolor command*/
          if((flag & LV_TXT_FLAG_RECOLOR) != 0) {
              if(lv_txt_is_cmd(&cmd_state, letter) != false) {
                  continue;   /*Skip the letter is it is part of a command*/
              }
          }
          /*Check for new line chars*/
          if((flag & LV_TXT_FLAG_NO_BREAK) == 0 && (letter == '\n' || letter == '\r')) {
              /*Handle \r\n as well*/
              uint32_t i_tmp = i;
              uint32_t letter_next = lv_txt_utf8_next(txt, &i_tmp);
              if(letter == '\r' &&  letter_next == '\n') i = i_tmp;
  
              return i;    /*Return with the first letter of the next line*/
  
          } else { /*Check the actual length*/
              cur_w += lv_font_get_width(font, letter);
  
              /*If the txt is too long then finish, this is the line end*/
              if(cur_w > max_width) {
                  /*If this a break char then break here.*/
                  if(is_break_char(letter)) {
                      /* Now 'i' points to the next char because of txt_utf8_next()
                       * But we need the first char of the next line so keep it.
                       * Hence do nothing here*/
                  }
                  /*If already a break character is found, then break there*/
                  if(last_break != NO_BREAK_FOUND ) {
                      i = last_break;
                  } else {
                      /* Now this character is out of the area so it will be first character of the next line*/
                      /* But 'i' already points to the next character (because of lv_txt_utf8_next) step beck one*/
                      lv_txt_utf8_prev(txt, &i);
                  }
  
                  /* Do not let to return without doing nothing.
                   * Find at least one character (Avoid infinite loop )*/
                  if(i == 0) lv_txt_utf8_next(txt, &i);
  
                  return i;
              }
              /*If this char still can fit to this line then check if 
               * txt can be broken here later */
              else if(is_break_char(letter)) {
                  last_break = i; /*Save the first char index  after break*/
              }
          }
          
          cur_w += letter_space;
      }
      
      return i;
  }
  
  /**
   * Give the length of a text with a given font
   * @param txt a '\0' terminate string
   * @param length length of 'txt' in bytes
   * @param font pointer to a font
   * @param letter_space letter space
   * @param flags settings for the text from 'txt_flag_t' enum
   * @return length of a char_num long text
   */
  lv_coord_t lv_txt_get_width(const char * txt, uint16_t length, 
                              const lv_font_t * font, lv_coord_t letter_space, lv_txt_flag_t flag)
  {
      if(txt == NULL) return 0;
      if(font == NULL) return 0;
  
      uint32_t i = 0;
      lv_coord_t width = 0;
      lv_txt_cmd_state_t cmd_state = LV_TXT_CMD_STATE_WAIT;
      uint32_t letter;
      
      if(length != 0) {
          while(i < length) {
              letter = lv_txt_utf8_next(txt, &i);
              if((flag & LV_TXT_FLAG_RECOLOR) != 0) {
                  if(lv_txt_is_cmd(&cmd_state, letter) != false) {
                      continue;
                  }
              }
              width += lv_font_get_width(font, letter);
              width += letter_space;
          }
  
          /*Trim closing spaces. Important when the text is aligned to the middle */
          for(i = length - 1; i > 0; i--) {
              if(txt[i] == ' ') {
                  width -= lv_font_get_width(font, txt[i]);
                  width -= letter_space;
              } else {
                  break;
              }
          }
      }
      
      return width;
  }
  
  /**
   * Check next character in a string and decide if the character is part of the command or not
   * @param state pointer to a txt_cmd_state_t variable which stores the current state of command processing
   *             (Initied. to TXT_CMD_STATE_WAIT )
   * @param c the current character
   * @return true: the character is part of a command and should not be written,
   *         false: the character should be written
   */
  bool lv_txt_is_cmd(lv_txt_cmd_state_t * state, uint32_t c)
  {
      bool ret = false;
  
      if(c == (uint32_t)LV_TXT_COLOR_CMD[0]) {
         if(*state == LV_TXT_CMD_STATE_WAIT) { /*Start char*/
             *state = LV_TXT_CMD_STATE_PAR;
             ret = true;
         } else if(*state == LV_TXT_CMD_STATE_PAR) { /*Other start char in parameter is escaped cmd. char */
             *state = LV_TXT_CMD_STATE_WAIT;
         }else if(*state == LV_TXT_CMD_STATE_IN) { /*Command end */
             *state = LV_TXT_CMD_STATE_WAIT;
             ret = true;
         }
     }
  
     /*Skip the color parameter and wait the space after it*/
     if(*state == LV_TXT_CMD_STATE_PAR) {
         if(c == ' ') {
             *state = LV_TXT_CMD_STATE_IN; /*After the parameter the text is in the command*/
         }
         ret = true;
     }
  
     return ret;
  }
  
  /**
   * Insert a string into an other
   * @param txt_buf the original text (must be big enough for the result text)
   * @param pos position to insert. Expressed in character index and not byte index (Different in UTF-8)
   *            0: before the original text, 1: after the first char etc.
   * @param ins_txt text to insert
   */
  void lv_txt_ins(char * txt_buf, uint32_t pos, const char * ins_txt)
  {
      uint32_t old_len = strlen(txt_buf);
      uint32_t ins_len = strlen(ins_txt);
      uint32_t new_len = ins_len + old_len;
  #if LV_TXT_UTF8 != 0
      pos = txt_utf8_get_byte_id(txt_buf, pos);   /*Convert to byte index instead of letter index*/
  #endif
      /*Copy the second part into the end to make place to text to insert*/
      uint32_t i;
      for(i = new_len; i >= pos + ins_len; i--){
          txt_buf[i] = txt_buf[i - ins_len];
      }
  
      /* Copy the text into the new space*/
      memcpy(txt_buf + pos, ins_txt, ins_len);
  }
  
  /**
   * Delete a part of a string
   * @param txt string to modify
   * @param pos position where to start the deleting (0: before the first char, 1: after the first char etc.)
   * @param len number of characters to delete
   */
  void lv_txt_cut(char * txt, uint32_t pos, uint32_t len)
  {
  
      uint32_t old_len = strlen(txt);
  #if LV_TXT_UTF8 != 0
      pos = txt_utf8_get_byte_id(txt, pos);   /*Convert to byte index instead of letter index*/
      len = txt_utf8_get_byte_id(&txt[pos], len);
  #endif
  
      /*Copy the second part into the end to make place to text to insert*/
      uint32_t i;
      for(i = pos; i <= old_len - len; i++){
          txt[i] = txt[i+len];
      }
  }
  
  /**
   * Give the size of an UTF-8 coded character
   * @param c A character where the UTF-8 character starts
   * @return length of the UTF-8 character (1,2,3 or 4). O on invalid code
   */
  uint8_t lv_txt_utf8_size(uint8_t c)
  {
      if((c & 0x80) == 0) return 1;
      else if((c & 0xE0) == 0xC0) return 2;
      else if((c & 0xF0) == 0xE0) return 3;
      else if((c & 0xF8) == 0xF0) return 4;
      return 0;
  }
  
  
  /**
   * Convert an Unicode letter to UTF-8.
   * @param letter_uni an Unicode letter
   * @return UTF-8 coded character in Little Endian to be compatible with C chars (e.g. 'Á', 'Ű')
   */
  uint32_t lv_txt_unicode_to_utf8(uint32_t letter_uni)
  {
      if(letter_uni < 128) return letter_uni;
      uint8_t bytes[4];
  
      if (letter_uni < 0x0800) {
          bytes[0] = ((letter_uni>>6)  & 0x1F) | 0xC0;
          bytes[1] = ((letter_uni>>0)  & 0x3F) | 0x80;
          bytes[2] = 0;
          bytes[3] = 0;
      }
      else if (letter_uni < 0x010000) {
          bytes[0] = ((letter_uni>>12) & 0x0F) | 0xE0;
          bytes[1] = ((letter_uni>>6)  & 0x3F) | 0x80;
          bytes[2] = ((letter_uni>>0)  & 0x3F) | 0x80;
          bytes[3] = 0;
      }
      else if (letter_uni < 0x110000) {
          bytes[0] = ((letter_uni>>18) & 0x07) | 0xF0;
          bytes[1] = ((letter_uni>>12) & 0x3F) | 0x80;
          bytes[2] = ((letter_uni>>6)  & 0x3F) | 0x80;
          bytes[3] = ((letter_uni>>0)  & 0x3F) | 0x80;
      }
  
      uint32_t *res_p = (uint32_t *)bytes;
      return *res_p;
  }
  
  /**
   * Decode an UTF-8 character from a string.
   * @param txt pointer to '\0' terminated string
   * @param i start byte index in 'txt' where to start.
   *          After call it will point to the next UTF-8 char in 'txt'.
   *          NULL to use txt[0] as index
   * @return the decoded Unicode character or 0 on invalid UTF-8 code
   */
  uint32_t lv_txt_utf8_next(const char * txt, uint32_t * i)
  {
  #if LV_TXT_UTF8 == 0
      if(i == NULL) return txt[1];    /*Get the next char */
  
      uint8_t letter = txt[*i] ;
      (*i)++;
      return letter;
  #else
      /* Unicode to UTF-8
       * 00000000 00000000 00000000 0xxxxxxx -> 0xxxxxxx
       * 00000000 00000000 00000yyy yyxxxxxx -> 110yyyyy 10xxxxxx
       * 00000000 00000000 zzzzyyyy yyxxxxxx -> 1110zzzz 10yyyyyy 10xxxxxx
       * 00000000 000wwwzz zzzzyyyy yyxxxxxx -> 11110www 10zzzzzz 10yyyyyy 10xxxxxx
       * */
  
      uint32_t result = 0;
  
      /*Dummy 'i' pointer is required*/
      uint32_t i_tmp = 0;
      if(i == NULL) i = &i_tmp;
  
      /*Normal ASCII*/
      if((txt[*i] & 0x80) == 0) {
          result = txt[*i];
          (*i)++;
      }
      /*Real UTF-8 decode*/
      else {
          /*2 bytes UTF-8 code*/
          if((txt[*i] & 0xE0) == 0xC0) {
              result = (uint32_t)(txt[*i] & 0x1F) << 6;
              (*i)++;
              if((txt[*i] & 0xC0) != 0x80) return 0;  /*Invalid UTF-8 code*/
              result += (txt[*i] & 0x3F);
              (*i)++;
          }
          /*3 bytes UTF-8 code*/
          else if((txt[*i] & 0xF0) == 0xE0) {
              result = (uint32_t)(txt[*i] & 0x0F) << 12;
              (*i)++;
  
              if((txt[*i] & 0xC0) != 0x80) return 0;  /*Invalid UTF-8 code*/
              result += (uint32_t)(txt[*i] & 0x3F) << 6;
              (*i)++;
  
              if((txt[*i] & 0xC0) != 0x80) return 0;  /*Invalid UTF-8 code*/
              result += (txt[*i] & 0x3F);
              (*i)++;
          }
          /*4 bytes UTF-8 code*/
          else if((txt[*i] & 0xF8) == 0xF0) {
              result = (uint32_t)(txt[*i] & 0x07) << 18;
              (*i)++;
  
              if((txt[*i] & 0xC0) != 0x80) return 0;  /*Invalid UTF-8 code*/
              result += (uint32_t)(txt[*i] & 0x3F) << 12;
              (*i)++;
  
              if((txt[*i] & 0xC0) != 0x80) return 0;  /*Invalid UTF-8 code*/
              result += (uint32_t)(txt[*i] & 0x3F) << 6;
              (*i)++;
  
              if((txt[*i] & 0xC0) != 0x80) return 0;  /*Invalid UTF-8 code*/
              result += txt[*i] & 0x3F;
              (*i)++;
          } else {
              (*i)++; /*Not UTF-8 char. Go the next.*/
          }
      }
      return result;
  #endif
  }
  
  /**
   * Get previous UTF-8 character form a string.
   * @param txt pointer to '\0' terminated string
   * @param i start byte index in 'txt' where to start. After the call it will point to the previous UTF-8 char in 'txt'.
   * @return the decoded Unicode character or 0 on invalid UTF-8 code
   */
  uint32_t lv_txt_utf8_prev(const char * txt, uint32_t * i)
  {
  #if LV_TXT_UTF8 == 0
      if(i == NULL) return *(txt- 1);    /*Get the prev. char */
  
      (*i)--;
      uint8_t letter = txt[*i] ;
  
      return letter;
  #else
      uint8_t c_size;
      uint8_t cnt = 0;
  
      /*Try to find a !0 long UTF-8 char by stepping one character back*/
      (*i)--;
      do {
          if(cnt >= 4) return 0;      /*No UTF-8 char found before the initial*/
  
          c_size = lv_txt_utf8_size(txt[*i]);
          if(c_size == 0) {
              if(*i != 0) (*i)--;
              else return 0;
          }
          cnt++;
      } while(c_size == 0);
  
      uint32_t i_tmp = *i;
      uint32_t letter = lv_txt_utf8_next(txt, &i_tmp);   /*Character found, get it*/
  
      return letter;
  #endif
  }
  
  /**
   * Convert a character index (in an UTF-8 text) to byte index.
   * E.g. in "AÁRT" index of 'R' is 2th char but start at byte 3 because 'Á' is 2 bytes long
   * @param txt a '\0' terminated UTF-8 string
   * @param utf8_id character index
   * @return byte index of the 'utf8_id'th letter
   */
  uint32_t txt_utf8_get_byte_id(const char * txt, uint32_t utf8_id)
  {
  #if LV_TXT_UTF8 == 0
      return utf8_id;     /*In Non UTF-8 no difference*/
  #else
      uint32_t i;
      uint32_t byte_cnt = 0;
      for(i = 0; i < utf8_id; i++) {
          byte_cnt += lv_txt_utf8_size(txt[byte_cnt]);
      }
  
      return byte_cnt;
  #endif
  }
  
  
  /**
   * Convert a byte index (in an UTF-8 text) to character index.
   * E.g. in "AÁRT" index of 'R' is 2th char but start at byte 3 because 'Á' is 2 bytes long
   * @param txt a '\0' terminated UTF-8 string
   * @param byte_id byte index
   * @return character index of the letter at 'byte_id'th position
   */
  uint32_t lv_txt_utf8_get_char_id(const char * txt, uint32_t byte_id)
  {
  #if LV_TXT_UTF8 == 0
      return byte_id;     /*In Non UTF-8 no difference*/
  #else
      uint32_t i = 0;
      uint32_t char_cnt = 0;
  
      while(i < byte_id) {
          lv_txt_utf8_next(txt, &i); /*'i' points to the next letter so use the prev. value*/
          char_cnt++;
      }
  
      return char_cnt;
  #endif
  
  }
  
  /**
   * Get the number of characters (and NOT bytes) in a string. Decode it with UTF-8 if enabled.
   * E.g.: "ÁBC" is 3 characters (but 4 bytes)
   * @param txt a '\0' terminated char string
   * @return number of characters
   */
  uint32_t lv_txt_get_length(const char * txt)
  {
  #if LV_TXT_UTF8 == 0
      return strlen(txt);
  #else
      uint32_t len = 0;
      uint32_t i = 0;
  
      while(txt[i] != '\0') {
          lv_txt_utf8_next(txt, &i);
          len++;
      }
  
      return len;
  #endif
  }
  
  /**********************
   *   STATIC FUNCTIONS
   **********************/
  
  /**
   * Test if char is break char or not (a text can broken here or not)
   * @param letter a letter
   * @return false: 'letter' is not break char
   */
  static bool is_break_char(uint32_t letter)
  {
      uint8_t i;
      bool ret = false;
      
      /*Compare the letter to TXT_BREAK_CHARS*/
      for(i = 0; LV_TXT_BREAK_CHARS[i] != '\0'; i++) {
          if(letter == (uint32_t)LV_TXT_BREAK_CHARS[i]) {
              ret = true; /*If match then it is break char*/
              break;
          }
      }
      
      return ret;
  }
  
  