/**
* @file lv_text.c
*
*/
/*********************
* INCLUDES
*********************/
#include "lv_txt.h"
#include "lv_math.h"
/*********************
* DEFINES
*********************/
#define NO_BREAK_FOUND UINT32_MAX
#ifndef LV_TXT_LINE_BREAK_LONG_LEN
#define LV_TXT_LINE_BREAK_LONG_LEN 12 /* If a character is at least this long, will break wherever "prettiest" */
#endif
#ifndef LV_TXT_LINE_BREAK_LONG_PRE_MIN_LEN
#define LV_TXT_LINE_BREAK_LONG_PRE_MIN_LEN 3 /* Minimum number of characters of a word to put on a line before a break */
#endif
#ifndef LV_TXT_LINE_BREAK_LONG_POST_MIN_LEN
#define LV_TXT_LINE_BREAK_LONG_POST_MIN_LEN 1 /* Minimum number of characters of a word to put on a line after a break */
#endif
/**********************
* TYPEDEFS
**********************/
/**********************
* STATIC PROTOTYPES
**********************/
static bool is_break_char(uint32_t letter);
#if LV_TXT_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);
#else
static uint8_t lv_txt_ascii_size(const char * str);
static uint32_t lv_txt_unicode_to_ascii(uint32_t letter_uni);
static uint32_t lv_txt_ascii_conv_wc(uint32_t c);
static uint32_t lv_txt_ascii_next(const char * txt, uint32_t * i);
static uint32_t lv_txt_ascii_prev(const char * txt, uint32_t * i_start);
static uint32_t lv_txt_ascii_get_byte_id(const char * txt, uint32_t utf8_id);
static uint32_t lv_txt_ascii_get_char_id(const char * txt, uint32_t byte_id);
static uint32_t lv_txt_ascii_get_length(const char * txt);
#endif
/**********************
* STATIC VARIABLES
**********************/
/**********************
* GLOBAL VARIABLES
**********************/
#if LV_TXT_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_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;
#else
uint8_t (*lv_txt_encoded_size)(const char *) = lv_txt_ascii_size;
uint32_t (*lv_txt_unicode_to_encoded)(uint32_t) = lv_txt_unicode_to_ascii;
uint32_t (*lv_txt_encoded_conv_wc)(uint32_t) = lv_txt_ascii_conv_wc;
uint32_t (*lv_txt_encoded_next)(const char *, uint32_t *) = lv_txt_ascii_next;
uint32_t (*lv_txt_encoded_prev)(const char *, uint32_t *) = lv_txt_ascii_prev;
uint32_t (*lv_txt_encoded_get_byte_id)(const char *, uint32_t) = lv_txt_ascii_get_byte_id;
uint32_t (*lv_encoded_get_char_id)(const char *, uint32_t) = lv_txt_ascii_get_char_id;
uint32_t (*lv_txt_get_encoded_length)(const char *) = lv_txt_ascii_get_length;
#endif
/**********************
* 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;
}
/*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 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;
lv_coord_t w_at_last_break = 0;
uint32_t n_char_since_last_break = 0; /* Used count word length of long words */
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') {
lv_coord_t letter_width;
letter = lv_txt_encoded_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(letter == '\n' || letter == '\r') {
uint32_t i_tmp = i;
uint32_t letter_next = lv_txt_encoded_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*/
n_char_since_last_break++;
letter_width = lv_font_get_width(font, letter);
cur_w += letter_width;
/* Get the length of the current work and determine best place
* to break the line. */
if(cur_w > max_width) {
if( last_break != NO_BREAK_FOUND ) {
/* Continue searching for next breakable character to see if the next word will fit */
uint32_t n_char_fit = n_char_since_last_break - 1;
if( n_char_since_last_break <= LV_TXT_LINE_BREAK_LONG_PRE_MIN_LEN ) {
i = last_break;
}
else {
uint32_t i_tmp = i;
cur_w -= w_at_last_break + letter_space; /*ignore the first letter_space after the break char */
bool other = true;
while(txt[i_tmp] != '\0') {
letter = lv_txt_encoded_next(txt, &i_tmp);
/*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(letter == '\n' || letter == '\r' || is_break_char(letter)) {
if(n_char_since_last_break >= LV_TXT_LINE_BREAK_LONG_LEN) {
/* Figure out the prettiest place to break */
uint32_t char_remain;
lv_txt_encoded_prev(txt, &i);
for(char_remain=n_char_since_last_break - n_char_fit;
char_remain < LV_TXT_LINE_BREAK_LONG_POST_MIN_LEN;
char_remain++) {
lv_txt_encoded_prev(txt, &i);
}
}
else{
i = last_break;
}
other = false;
break;
}
n_char_since_last_break++;
lv_coord_t letter_width2 = lv_font_get_width(font, letter);
cur_w += letter_width2;
if(cur_w > max_width) {
/* Current letter already exceeds, return previous */
lv_txt_encoded_prev(txt, &i);
other = false;
break;
}
if(letter_width2 > 0){
cur_w += letter_space;
}
}
if( other ) {
if(n_char_since_last_break >= LV_TXT_LINE_BREAK_LONG_LEN) {
/* Figure out the prettiest place to break */
uint32_t char_remain;
lv_txt_encoded_prev(txt, &i);
for(char_remain=n_char_since_last_break - n_char_fit;
char_remain < LV_TXT_LINE_BREAK_LONG_POST_MIN_LEN;
char_remain++){
lv_txt_encoded_prev(txt, &i);
}
}
else{
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_encoded_prev(txt, &i);
}
/* Do not let to return without doing nothing.
* Find at least one character (Avoid infinite loop )*/
if(i == 0) lv_txt_encoded_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*/
w_at_last_break = cur_w;
if(letter_width > 0) {
w_at_last_break += letter_space;
}
n_char_since_last_break = 0;
}
}
if(letter_width > 0) {
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 byte count and not characters (Á is 1 character but 2 bytes in UTF-8)
* @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_encoded_next(txt, &i);
if((flag & LV_TXT_FLAG_RECOLOR) != 0) {
if(lv_txt_is_cmd(&cmd_state, letter) != false) {
continue;
}
}
lv_coord_t char_width = lv_font_get_width(font, letter);
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;
}
/**
* 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 = lv_txt_encoded_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 = 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);
#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];
}
}
/*******************************
* UTF-8 ENCODER/DECOER
******************************/
#if LV_TXT_UTF8
/**
* 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). O on invalid code
*/
static uint8_t lv_txt_utf8_size(const char * str)
{
if((str[0] & 0x80) == 0) return 1;
else if((str[0] & 0xE0) == 0xC0) return 2;
else if((str[0] & 0xF0) == 0xE0) return 3;
else if((str[0] & 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')
*/
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;
}
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)
{
/*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];
memcpy(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;
}
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((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;
}
/**
* 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; i++) {
byte_cnt += lv_txt_encoded_size(&txt[byte_cnt]);
}
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)
{
#if LV_TXT_UTF8 == 0
return strlen(txt);
#else
uint32_t len = 0;
uint32_t i = 0;
while(txt[i] != '\0') {
lv_txt_encoded_next(txt, &i);
len++;
}
return len;
#endif
}
#else
/**
* 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). O on invalid code
*/
static uint8_t lv_txt_ascii_size(const char * str)
{
return 1;
}
/**
* 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')
*/
static uint32_t lv_txt_unicode_to_ascii(uint32_t letter_uni)
{
if(letter_uni < 128) 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_ascii_conv_wc(uint32_t c)
{
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_ascii_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 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_ascii_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 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_ascii_get_byte_id(const char * txt, uint32_t utf8_id)
{
return utf8_id; /*In Non encoded no difference*/
}
/**
* 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_ascii_get_char_id(const char * txt, uint32_t byte_id)
{
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_ascii_get_length(const char * txt)
{
return strlen(txt);
}
#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;
}