/**
  * @file lv_txt.c
  *
  */
 
 /*********************
  *      INCLUDES
  *********************/
 #include <stdarg.h>
 #include "lv_txt.h"
 #include "lv_txt_ap.h"
 #include "lv_math.h"
 #include "lv_log.h"
 #include "lv_mem.h"
 #include "lv_assert.h"
 
 /*********************
  *      DEFINES
  *********************/
 #define NO_BREAK_FOUND UINT32_MAX
 
 /**********************
  *      TYPEDEFS
  **********************/
 
 /**********************
  *  STATIC PROTOTYPES
  **********************/
 
 #if LV_TXT_ENC == LV_TXT_ENC_UTF8
     static uint8_t lv_txt_utf8_size(const char * str);
     static uint32_t lv_txt_unicode_to_utf8(uint32_t letter_uni);
     static uint32_t lv_txt_utf8_conv_wc(uint32_t c);
     static uint32_t lv_txt_utf8_next(const char * txt, uint32_t * i);
     static uint32_t lv_txt_utf8_prev(const char * txt, uint32_t * i_start);
     static uint32_t lv_txt_utf8_get_byte_id(const char * txt, uint32_t utf8_id);
     static uint32_t lv_txt_utf8_get_char_id(const char * txt, uint32_t byte_id);
     static uint32_t lv_txt_utf8_get_length(const char * txt);
 #elif LV_TXT_ENC == LV_TXT_ENC_ASCII
     static uint8_t lv_txt_iso8859_1_size(const char * str);
     static uint32_t lv_txt_unicode_to_iso8859_1(uint32_t letter_uni);
     static uint32_t lv_txt_iso8859_1_conv_wc(uint32_t c);
     static uint32_t lv_txt_iso8859_1_next(const char * txt, uint32_t * i);
     static uint32_t lv_txt_iso8859_1_prev(const char * txt, uint32_t * i_start);
     static uint32_t lv_txt_iso8859_1_get_byte_id(const char * txt, uint32_t utf8_id);
     static uint32_t lv_txt_iso8859_1_get_char_id(const char * txt, uint32_t byte_id);
     static uint32_t lv_txt_iso8859_1_get_length(const char * txt);
 #endif
 /**********************
  *  STATIC VARIABLES
  **********************/
 
 /**********************
  *  GLOBAL VARIABLES
  **********************/
 #if LV_TXT_ENC == LV_TXT_ENC_UTF8
     uint8_t (*_lv_txt_encoded_size)(const char *)                   = lv_txt_utf8_size;
     uint32_t (*_lv_txt_unicode_to_encoded)(uint32_t)                = lv_txt_unicode_to_utf8;
     uint32_t (*_lv_txt_encoded_conv_wc)(uint32_t)                   = lv_txt_utf8_conv_wc;
     uint32_t (*_lv_txt_encoded_next)(const char *, uint32_t *)      = lv_txt_utf8_next;
     uint32_t (*_lv_txt_encoded_prev)(const char *, uint32_t *)      = lv_txt_utf8_prev;
     uint32_t (*_lv_txt_encoded_get_byte_id)(const char *, uint32_t) = lv_txt_utf8_get_byte_id;
     uint32_t (*_lv_txt_encoded_get_char_id)(const char *, uint32_t) = lv_txt_utf8_get_char_id;
     uint32_t (*_lv_txt_get_encoded_length)(const char *)            = lv_txt_utf8_get_length;
 #elif LV_TXT_ENC == LV_TXT_ENC_ASCII
     uint8_t (*_lv_txt_encoded_size)(const char *)                   = lv_txt_iso8859_1_size;
     uint32_t (*_lv_txt_unicode_to_encoded)(uint32_t)                = lv_txt_unicode_to_iso8859_1;
     uint32_t (*_lv_txt_encoded_conv_wc)(uint32_t)                   = lv_txt_iso8859_1_conv_wc;
     uint32_t (*_lv_txt_encoded_next)(const char *, uint32_t *)      = lv_txt_iso8859_1_next;
     uint32_t (*_lv_txt_encoded_prev)(const char *, uint32_t *)      = lv_txt_iso8859_1_prev;
     uint32_t (*_lv_txt_encoded_get_byte_id)(const char *, uint32_t) = lv_txt_iso8859_1_get_byte_id;
     uint32_t (*_lv_txt_encoded_get_char_id)(const char *, uint32_t)     = lv_txt_iso8859_1_get_char_id;
     uint32_t (*_lv_txt_get_encoded_length)(const char *)            = lv_txt_iso8859_1_get_length;
 
 #endif
 
 /**********************
  *      MACROS
  **********************/
 
 #define LV_IS_ASCII(value)              ((value & 0x80U) == 0x00U)
 #define LV_IS_2BYTES_UTF8_CODE(value)   ((value & 0xE0U) == 0xC0U)
 #define LV_IS_3BYTES_UTF8_CODE(value)   ((value & 0xF0U) == 0xE0U)
 #define LV_IS_4BYTES_UTF8_CODE(value)   ((value & 0xF8U) == 0xF0U)
 #define LV_IS_INVALID_UTF8_CODE(value)  ((value & 0xC0U) != 0x80U)
 
 /**********************
  *   GLOBAL FUNCTIONS
  **********************/
 
 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_text_flag_t flag)
 {
     size_res->x = 0;
     size_res->y = 0;
 
     if(text == NULL) return;
     if(font == NULL) return;
 
     if(flag & LV_TEXT_FLAG_EXPAND) max_width = LV_COORD_MAX;
 
     uint32_t line_start     = 0;
     uint32_t new_line_start = 0;
     uint16_t letter_height = lv_font_get_line_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, NULL, flag);
 
         if((unsigned long)size_res->y + (unsigned long)letter_height + (unsigned long)line_space > LV_MAX_OF(lv_coord_t)) {
             LV_LOG_WARN("lv_txt_get_size: integer overflow while calculating text height");
             return;
         }
         else {
             size_res->y += letter_height;
             size_res->y += line_space;
         }
 
         /*Calculate the longest line*/
         lv_coord_t act_line_length = lv_txt_get_width(&text[line_start], new_line_start - line_start, font, letter_space,
                                                       flag);
 
         size_res->x = LV_MAX(act_line_length, size_res->x);
         line_start  = new_line_start;
     }
 
     /*Make the text one line taller if the last character is '\n' or '\r'*/
     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 word of text. A word is delimited by break characters.
  *
  * If the word cannot fit in the max_width space, obey LV_TXT_LINE_BREAK_LONG_* rules.
  *
  * If the next word cannot fit anything, return 0.
  *
  * If the first character is a break character, returns the next index.
  *
  * Example calls from lv_txt_get_next_line() assuming sufficient max_width and
  * txt = "Test text\n"
  *        0123456789
  *
  * Calls would be as follows:
  *     1. Return i=4, pointing at breakchar ' ', for the string "Test"
  *     2. Return i=5, since i=4 was a breakchar.
  *     3. Return i=9, pointing at breakchar '\n'
  *     4. Parenting lv_txt_get_next_line() would detect subsequent '\0'
  *
  * TODO: Returned word_w_ptr may overestimate the returned word's width when
  * max_width is reached. In current usage, this has no impact.
  *
  * @param txt a '\0' terminated string
  * @param font pointer to a font
  * @param letter_space letter space
  * @param max_width max width of the text (break the lines to fit this size). Set COORD_MAX to avoid line breaks
  * @param flags settings for the text from 'txt_flag_type' enum
  * @param[out] word_w_ptr width (in pixels) of the parsed word. May be NULL.
  * @param cmd_state pointer to a txt_cmd_state_t variable which stores the current state of command processing
  * @param force Force return the fraction of the word that can fit in the provided space.
  * @return the index of the first char of the next word (in byte index not letter index. With UTF-8 they are different)
  */
 static uint32_t lv_txt_get_next_word(const char * txt, const lv_font_t * font,
                                      lv_coord_t letter_space, lv_coord_t max_width,
                                      lv_text_flag_t flag, uint32_t * word_w_ptr, lv_text_cmd_state_t * cmd_state, bool force)
 {
     if(txt == NULL || txt[0] == '\0') return 0;
     if(font == NULL) return 0;
 
     if(flag & LV_TEXT_FLAG_EXPAND) max_width = LV_COORD_MAX;
 
     uint32_t i = 0, i_next = 0, i_next_next = 0;  /*Iterating index into txt*/
     uint32_t letter = 0;      /*Letter at i*/
     uint32_t letter_next = 0; /*Letter at i_next*/
     lv_coord_t letter_w;
     lv_coord_t cur_w = 0;  /*Pixel Width of transversed string*/
     uint32_t word_len = 0;   /*Number of characters in the transversed word*/
     uint32_t break_index = NO_BREAK_FOUND; /*only used for "long" words*/
     uint32_t break_letter_count = 0; /*Number of characters up to the long word break point*/
 
     letter = _lv_txt_encoded_next(txt, &i_next);
     i_next_next = i_next;
 
     /*Obtain the full word, regardless if it fits or not in max_width*/
     while(txt[i] != '\0') {
         letter_next = _lv_txt_encoded_next(txt, &i_next_next);
         word_len++;
 
         /*Handle the recolor command*/
         if((flag & LV_TEXT_FLAG_RECOLOR) != 0) {
             if(_lv_txt_is_cmd(cmd_state, letter) != false) {
                 i = i_next;
                 i_next = i_next_next;
                 letter = letter_next;
                 continue;   /*Skip the letter if it is part of a command*/
             }
         }
 
         letter_w = lv_font_get_glyph_width(font, letter, letter_next);
         cur_w += letter_w;
 
         if(letter_w > 0) {
             cur_w += letter_space;
         }
 
         /*Test if this character fits within max_width*/
         if(break_index == NO_BREAK_FOUND && (cur_w - letter_space) > max_width) {
             break_index = i;
             break_letter_count = word_len - 1;
             /*break_index is now pointing at the character that doesn't fit*/
         }
 
         /*Check for new line chars and breakchars*/
         if(letter == '\n' || letter == '\r' || _lv_txt_is_break_char(letter)) {
             /*Update the output width on the first character if it fits.
              *Must do this here in case first letter is a break character.*/
             if(i == 0 && break_index == NO_BREAK_FOUND && word_w_ptr != NULL) *word_w_ptr = cur_w;
             word_len--;
             break;
         }
 
         /*Update the output width*/
         if(word_w_ptr != NULL && break_index == NO_BREAK_FOUND) *word_w_ptr = cur_w;
 
         i = i_next;
         i_next = i_next_next;
         letter = letter_next;
     }
 
     /*Entire Word fits in the provided space*/
     if(break_index == NO_BREAK_FOUND) {
         if(word_len == 0 || (letter == '\r' && letter_next == '\n')) i = i_next;
         return i;
     }
 
 #if LV_TXT_LINE_BREAK_LONG_LEN > 0
     /*Word doesn't fit in provided space, but isn't "long"*/
     if(word_len < LV_TXT_LINE_BREAK_LONG_LEN) {
         if(force) return break_index;
         if(word_w_ptr != NULL) *word_w_ptr = 0; /*Return no word*/
         return 0;
     }
 
     /*Word is "long," but insufficient amounts can fit in provided space*/
     if(break_letter_count < LV_TXT_LINE_BREAK_LONG_PRE_MIN_LEN) {
         if(force) return break_index;
         if(word_w_ptr != NULL) *word_w_ptr = 0;
         return 0;
     }
 
     /*Word is a "long", but letters may need to be better distributed*/
     {
         i = break_index;
         int32_t n_move = LV_TXT_LINE_BREAK_LONG_POST_MIN_LEN - (word_len - break_letter_count);
         /*Move pointer "i" backwards*/
         for(; n_move > 0; n_move--) {
             _lv_txt_encoded_prev(txt, &i);
             // TODO: it would be appropriate to update the returned word width here
             // However, in current usage, this doesn't impact anything.
         }
     }
     return i;
 #else
     if(force) return break_index;
     if(word_w_ptr != NULL) *word_w_ptr = 0; /*Return no word*/
     (void) break_letter_count;
     return 0;
 #endif
 }
 
 uint32_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_coord_t * used_width, lv_text_flag_t flag)
 {
     if(used_width) *used_width = 0;
 
     if(txt == NULL) return 0;
     if(txt[0] == '\0') return 0;
     if(font == NULL) return 0;
 
     lv_coord_t line_w = 0;
 
     /*If max_width doesn't mater simply find the new line character
      *without thinking about word wrapping*/
     if((flag & LV_TEXT_FLAG_EXPAND) || (flag & LV_TEXT_FLAG_FIT)) {
         uint32_t i;
         for(i = 0; txt[i] != '\n' && txt[i] != '\r' && txt[i] != '\0'; i++) {
             /*Just find the new line chars or string ends by incrementing `i`*/
         }
         if(txt[i] != '\0') i++;    /*To go beyond `\n`*/
         if(used_width) *used_width = -1;
         return i;
     }
 
     if(flag & LV_TEXT_FLAG_EXPAND) max_width = LV_COORD_MAX;
     lv_text_cmd_state_t cmd_state = LV_TEXT_CMD_STATE_WAIT;
     uint32_t i = 0;                                        /*Iterating index into txt*/
 
     while(txt[i] != '\0' && max_width > 0) {
         uint32_t word_w = 0;
         uint32_t advance = lv_txt_get_next_word(&txt[i], font, letter_space, max_width, flag, &word_w, &cmd_state, i == 0);
         max_width -= word_w;
         line_w += word_w;
 
         if(advance == 0) {
             break;
         }
 
         i += advance;
 
         if(txt[0] == '\n' || txt[0] == '\r') break;
 
         if(txt[i] == '\n' || txt[i] == '\r') {
             i++;  /*Include the following newline in the current line*/
             break;
         }
 
     }
 
     /*Always step at least one to avoid infinite loops*/
     if(i == 0) {
         uint32_t letter = _lv_txt_encoded_next(txt, &i);
         if(used_width != NULL) {
             line_w = lv_font_get_glyph_width(font, letter, '\0');
         }
     }
 
     if(used_width != NULL) {
         *used_width = line_w;
     }
 
     return i;
 }
 
 lv_coord_t lv_txt_get_width(const char * txt, uint32_t length, const lv_font_t * font, lv_coord_t letter_space,
                             lv_text_flag_t flag)
 {
     if(txt == NULL) return 0;
     if(font == NULL) return 0;
     if(txt[0] == '\0') return 0;
 
     uint32_t i                   = 0;
     lv_coord_t width             = 0;
     lv_text_cmd_state_t cmd_state = LV_TEXT_CMD_STATE_WAIT;
 
     if(length != 0) {
         while(i < length) {
             uint32_t letter;
             uint32_t letter_next;
             _lv_txt_encoded_letter_next_2(txt, &letter, &letter_next, &i);
 
             if((flag & LV_TEXT_FLAG_RECOLOR) != 0) {
                 if(_lv_txt_is_cmd(&cmd_state, letter) != false) {
                     continue;
                 }
             }
 
             lv_coord_t char_width = lv_font_get_glyph_width(font, letter, letter_next);
             if(char_width > 0) {
                 width += char_width;
                 width += letter_space;
             }
         }
 
         if(width > 0) {
             width -= letter_space; /*Trim the last letter space. Important if the text is center
                                       aligned*/
         }
     }
 
     return width;
 }
 
 bool _lv_txt_is_cmd(lv_text_cmd_state_t * state, uint32_t c)
 {
     bool ret = false;
 
     if(c == (uint32_t)LV_TXT_COLOR_CMD[0]) {
         if(*state == LV_TEXT_CMD_STATE_WAIT) { /*Start char*/
             *state = LV_TEXT_CMD_STATE_PAR;
             ret    = true;
         }
         /*Other start char in parameter is escaped cmd. char*/
         else if(*state == LV_TEXT_CMD_STATE_PAR) {
             *state = LV_TEXT_CMD_STATE_WAIT;
         }
         /*Command end*/
         else if(*state == LV_TEXT_CMD_STATE_IN) {
             *state = LV_TEXT_CMD_STATE_WAIT;
             ret    = true;
         }
     }
 
     /*Skip the color parameter and wait the space after it*/
     if(*state == LV_TEXT_CMD_STATE_PAR) {
         if(c == ' ') {
             *state = LV_TEXT_CMD_STATE_IN; /*After the parameter the text is in the command*/
         }
         ret = true;
     }
 
     return ret;
 }
 
 void _lv_txt_ins(char * txt_buf, uint32_t pos, const char * ins_txt)
 {
     if(txt_buf == NULL || ins_txt == NULL) return;
 
     size_t old_len = strlen(txt_buf);
     size_t ins_len = strlen(ins_txt);
     if(ins_len == 0) return;
 
     size_t new_len = ins_len + old_len;
     pos              = _lv_txt_encoded_get_byte_id(txt_buf, pos); /*Convert to byte index instead of letter index*/
 
     /*Copy the second part into the end to make place to text to insert*/
     size_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*/
     lv_memcpy_small(txt_buf + pos, ins_txt, ins_len);
 }
 
 void _lv_txt_cut(char * txt, uint32_t pos, uint32_t len)
 {
     if(txt == NULL) return;
 
     size_t old_len = strlen(txt);
 
     pos = _lv_txt_encoded_get_byte_id(txt, pos); /*Convert to byte index instead of letter index*/
     len = _lv_txt_encoded_get_byte_id(&txt[pos], len);
 
     /*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];
     }
 }
 
 char * _lv_txt_set_text_vfmt(const char * fmt, va_list ap)
 {
     /*Allocate space for the new text by using trick from C99 standard section 7.19.6.12*/
     va_list ap_copy;
     va_copy(ap_copy, ap);
     uint32_t len = lv_vsnprintf(NULL, 0, fmt, ap_copy);
     va_end(ap_copy);
 
     char * text = 0;
 #if LV_USE_ARABIC_PERSIAN_CHARS
     /*Put together the text according to the format string*/
     char * raw_txt = lv_mem_buf_get(len + 1);
     LV_ASSERT_MALLOC(raw_txt);
     if(raw_txt == NULL) {
         return NULL;
     }
 
     lv_vsnprintf(raw_txt, len + 1, fmt, ap);
 
     /*Get the size of the Arabic text and process it*/
     size_t len_ap = _lv_txt_ap_calc_bytes_cnt(raw_txt);
     text = lv_mem_alloc(len_ap + 1);
     LV_ASSERT_MALLOC(text);
     if(text == NULL) {
         return NULL;
     }
     _lv_txt_ap_proc(raw_txt, text);
 
     lv_mem_buf_release(raw_txt);
 #else
     text = lv_mem_alloc(len + 1);
     LV_ASSERT_MALLOC(text);
     if(text == NULL) {
         return NULL;
     }
     text[len] = 0; /*Ensure NULL termination*/
 
     lv_vsnprintf(text, len + 1, fmt, ap);
 #endif
 
     return text;
 }
 
 void _lv_txt_encoded_letter_next_2(const char * txt, uint32_t * letter, uint32_t * letter_next, uint32_t * ofs)
 {
     *letter = _lv_txt_encoded_next(txt, ofs);
     *letter_next = *letter != '\0' ? _lv_txt_encoded_next(&txt[*ofs], NULL) : 0;
 }
 
 #if LV_TXT_ENC == LV_TXT_ENC_UTF8
 /*******************************
  *   UTF-8 ENCODER/DECODER
  ******************************/
 
 /**
  * Give the size of an UTF-8 coded character
  * @param str pointer to a character in a string
  * @return length of the UTF-8 character (1,2,3 or 4), 0 on invalid code.
  */
 static uint8_t lv_txt_utf8_size(const char * str)
 {
     if(LV_IS_ASCII(str[0]))
         return 1;
     else if(LV_IS_2BYTES_UTF8_CODE(str[0]))
         return 2;
     else if(LV_IS_3BYTES_UTF8_CODE(str[0]))
         return 3;
     else if(LV_IS_4BYTES_UTF8_CODE(str[0]))
         return 4;
     return 0;
 }
 
 /**
  * Convert a Unicode letter to UTF-8.
  * @param letter_uni a Unicode letter
  * @return UTF-8 coded character in Little Endian to be compatible with C chars (e.g. 'Á', 'Ű')
  */
 static 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;
     }
     else {
         return 0;
     }
 
     uint32_t * res_p = (uint32_t *)bytes;
     return *res_p;
 }
 
 /**
  * Convert a wide character, e.g. 'Á' little endian to be UTF-8 compatible
  * @param c a wide character or a  Little endian number
  * @return `c` in big endian
  */
 static uint32_t lv_txt_utf8_conv_wc(uint32_t c)
 {
 #if LV_BIG_ENDIAN_SYSTEM == 0
     /*Swap the bytes (UTF-8 is big endian, but the MCUs are little endian)*/
     if((c & 0x80) != 0) {
         uint32_t swapped;
         uint8_t c8[4];
         lv_memcpy_small(c8, &c, 4);
         swapped = (c8[0] << 24) + (c8[1] << 16) + (c8[2] << 8) + (c8[3]);
         uint8_t i;
         for(i = 0; i < 4; i++) {
             if((swapped & 0xFF) == 0)
                 swapped = (swapped >> 8); /*Ignore leading zeros (they were in the end originally)*/
         }
         c = swapped;
     }
 #endif
     return c;
 }
 
 /**
  * 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
  */
 static uint32_t lv_txt_utf8_next(const char * txt, uint32_t * i)
 {
     /**
      * 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(LV_IS_ASCII(txt[*i])) {
         result = txt[*i];
         (*i)++;
     }
     /*Real UTF-8 decode*/
     else {
         /*2 bytes UTF-8 code*/
         if(LV_IS_2BYTES_UTF8_CODE(txt[*i])) {
             result = (uint32_t)(txt[*i] & 0x1F) << 6;
             (*i)++;
             if(LV_IS_INVALID_UTF8_CODE(txt[*i])) return 0;
             result += (txt[*i] & 0x3F);
             (*i)++;
         }
         /*3 bytes UTF-8 code*/
         else if(LV_IS_3BYTES_UTF8_CODE(txt[*i])) {
             result = (uint32_t)(txt[*i] & 0x0F) << 12;
             (*i)++;
 
             if(LV_IS_INVALID_UTF8_CODE(txt[*i])) return 0;
             result += (uint32_t)(txt[*i] & 0x3F) << 6;
             (*i)++;
 
             if(LV_IS_INVALID_UTF8_CODE(txt[*i])) return 0;
             result += (txt[*i] & 0x3F);
             (*i)++;
         }
         /*4 bytes UTF-8 code*/
         else if(LV_IS_4BYTES_UTF8_CODE(txt[*i])) {
             result = (uint32_t)(txt[*i] & 0x07) << 18;
             (*i)++;
 
             if(LV_IS_INVALID_UTF8_CODE(txt[*i])) return 0;
             result += (uint32_t)(txt[*i] & 0x3F) << 12;
             (*i)++;
 
             if(LV_IS_INVALID_UTF8_CODE(txt[*i])) return 0;
             result += (uint32_t)(txt[*i] & 0x3F) << 6;
             (*i)++;
 
             if(LV_IS_INVALID_UTF8_CODE(txt[*i])) return 0;
             result += txt[*i] & 0x3F;
             (*i)++;
         }
         else {
             (*i)++; /*Not UTF-8 char. Go the next.*/
         }
     }
     return result;
 }
 
 /**
  * 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
  */
 static uint32_t lv_txt_utf8_prev(const char * txt, uint32_t * i)
 {
     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_encoded_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_encoded_next(txt, &i_tmp); /*Character found, get it*/
 
     return letter;
 }
 
 /**
  * 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
  */
 static uint32_t lv_txt_utf8_get_byte_id(const char * txt, uint32_t utf8_id)
 {
     uint32_t i;
     uint32_t byte_cnt = 0;
     for(i = 0; i < utf8_id && txt[byte_cnt] != '\0'; i++) {
         uint8_t c_size = _lv_txt_encoded_size(&txt[byte_cnt]);
         /* If the char was invalid tell it's 1 byte long*/
         byte_cnt += c_size ? c_size : 1;
     }
 
     return byte_cnt;
 }
 
 /**
  * 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
  */
 static uint32_t lv_txt_utf8_get_char_id(const char * txt, uint32_t byte_id)
 {
     uint32_t i        = 0;
     uint32_t char_cnt = 0;
 
     while(i < byte_id) {
         _lv_txt_encoded_next(txt, &i); /*'i' points to the next letter so use the prev. value*/
         char_cnt++;
     }
 
     return char_cnt;
 }
 
 /**
  * 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
  */
 static uint32_t lv_txt_utf8_get_length(const char * txt)
 {
     uint32_t len = 0;
     uint32_t i   = 0;
 
     while(txt[i] != '\0') {
         _lv_txt_encoded_next(txt, &i);
         len++;
     }
 
     return len;
 }
 
 #elif LV_TXT_ENC == LV_TXT_ENC_ASCII
 /*******************************
  *  ASCII ENCODER/DECODER
  ******************************/
 
 /**
  * Give the size of an ISO8859-1 coded character
  * @param str pointer to a character in a string
  * @return length of the UTF-8 character (1,2,3 or 4). O on invalid code
  */
 static uint8_t lv_txt_iso8859_1_size(const char * str)
 {
     LV_UNUSED(str); /*Unused*/
     return 1;
 }
 
 /**
  * Convert a Unicode letter to ISO8859-1.
  * @param letter_uni a Unicode letter
  * @return ISO8859-1 coded character in Little Endian to be compatible with C chars (e.g. 'Á', 'Ű')
  */
 static uint32_t lv_txt_unicode_to_iso8859_1(uint32_t letter_uni)
 {
     if(letter_uni < 256)
         return letter_uni;
     else
         return ' ';
 }
 
 /**
  * Convert wide characters to ASCII, however wide characters in ASCII range (e.g. 'A') are ASCII compatible by default.
  * So this function does nothing just returns with `c`.
  * @param c a character, e.g. 'A'
  * @return same as `c`
  */
 static uint32_t lv_txt_iso8859_1_conv_wc(uint32_t c)
 {
     return c;
 }
 
 /**
  * Decode an ISO8859-1 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
  */
 static uint32_t lv_txt_iso8859_1_next(const char * txt, uint32_t * i)
 {
     if(i == NULL) return txt[1]; /*Get the next char*/
 
     uint8_t letter = txt[*i];
     (*i)++;
     return letter;
 }
 
 /**
  * Get previous ISO8859-1 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
  */
 static uint32_t lv_txt_iso8859_1_prev(const char * txt, uint32_t * i)
 {
     if(i == NULL) return *(txt - 1); /*Get the prev. char*/
 
     (*i)--;
     uint8_t letter = txt[*i];
 
     return letter;
 }
 
 /**
  * Convert a character index (in an ISO8859-1 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
  */
 static uint32_t lv_txt_iso8859_1_get_byte_id(const char * txt, uint32_t utf8_id)
 {
     LV_UNUSED(txt); /*Unused*/
     return utf8_id; /*In Non encoded no difference*/
 }
 
 /**
  * Convert a byte index (in an ISO8859-1 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
  */
 static uint32_t lv_txt_iso8859_1_get_char_id(const char * txt, uint32_t byte_id)
 {
     LV_UNUSED(txt); /*Unused*/
     return byte_id; /*In Non encoded no difference*/
 }
 
 /**
  * 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
  */
 static uint32_t lv_txt_iso8859_1_get_length(const char * txt)
 {
     return strlen(txt);
 }
 #else
 
 #error "Invalid character encoding. See `LV_TXT_ENC` in `lv_conf.h`"
 
 #endif

© 2023 acidvegas, inc • generated with stagit