ESPTerm - ESP8266 terminal emulator. Branches: [master] patches, [work] next release
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espterm-firmware/user/apars_utf8.c

85 lines
1.5 KiB

//
// Created by MightyPork on 2017/08/20.
//
// UTF-8 parser - collects bytes of a code point before writing them
// into a screen cell.
//
#include "apars_utf8.h"
#include "apars_logging.h"
#include "screen.h"
static char utf_collect[4];
static int utf_i = 0;
static int utf_j = 0;
/**
* Clear the buffer where we collect pieces of a code point.
* This is used for parser reset.
*/
void ICACHE_FLASH_ATTR
apars_reset_utf8buffer(void)
{
utf_i = 0;
utf_j = 0;
memset(utf_collect, 0, 4);
}
/**
* Handle a received plain character
* @param c - received character
*/
void ICACHE_FLASH_ATTR
apars_handle_plainchar(char c)
{
// collecting unicode glyphs...
if (c & 0x80) {
if (utf_i == 0) {
// start
if (c == 192 || c == 193 || c >= 245) {
// forbidden codes (would be an overlong sequence)
goto fail;
}
if ((c & 0xE0) == 0xC0) {
utf_i = 2;
}
else if ((c & 0xF0) == 0xE0) {
utf_i = 3;
}
else if ((c & 0xF8) == 0xF0) {
utf_i = 4;
}
else {
// chars over 127 that don't start unicode sequences
goto fail;
}
utf_collect[0] = c;
utf_j = 1;
}
else {
if ((c & 0xC0) != 0x80) {
goto fail;
}
else {
utf_collect[utf_j++] = c;
if (utf_j >= utf_i) {
screen_putchar(utf_collect);
apars_reset_utf8buffer();
}
}
}
}
else {
utf_collect[0] = c;
utf_collect[1] = 0; // just to make sure it's closed...
screen_putchar(utf_collect);
}
return;
fail:
ansi_warn("Bad UTF-8: %0Xh", c);
apars_reset_utf8buffer();
}