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LibVT: Add incremental UTF-8 parsing to the terminal input handler

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Instead of relying on the GUI code to handle UTF-8, we now process
and parse the incoming data into 32-bit codepoints ourselves.

This means that you can now show emojis in the terminal and they will
only take up one character cell each. :^)
This commit is contained in:
Andreas Kling 2020-05-16 19:47:49 +02:00
parent 06f3eb0ecd
commit b8498dc55e
2 changed files with 70 additions and 14 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

74
Libraries/LibVT/Terminal.cpp
View file

@ -809,6 +809,23 @@ void Terminal::on_input(u8 ch)
#ifdef TERMINAL_DEBUG
dbgprintf("Terminal::on_char: %b (%c), fg=%u, bg=%u\n", ch, ch, m_current_attribute.foreground_color, m_current_attribute.background_color);
#endif
auto fail_utf8_parse = [this] {
m_parser_state = Normal;
on_codepoint('%');
};
auto advance_utf8_parse = [this, ch] {
m_parser_codepoint <<= 6;
m_parser_codepoint |= ch & 0x3f;
if (m_parser_state == UTF8Needs1Byte) {
on_codepoint(m_parser_codepoint);
m_parser_state = Normal;
} else {
m_parser_state = (ParserState)(m_parser_state + 1);
}
};
switch (m_parser_state) {
case GotEscape:
if (ch == '[') {
@ -888,8 +905,36 @@ void Terminal::on_input(u8 ch)
m_parser_state = Normal;
m_swallow_current = false;
return;
case UTF8Needs1Byte:
case UTF8Needs2Bytes:
case UTF8Needs3Bytes:
if ((ch & 0xc0) != 0x80) {
fail_utf8_parse();
} else {
advance_utf8_parse();
}
return;
case Normal:
break;
if (!(ch & 0x80))
break;
if ((ch & 0xe0) == 0xc0) {
m_parser_state = UTF8Needs1Byte;
m_parser_codepoint = ch & 0x1f;
return;
}
if ((ch & 0xf0) == 0xe0) {
m_parser_state = UTF8Needs2Bytes;
m_parser_codepoint = ch & 0x0f;
return;
}
if ((ch & 0xf8) == 0xf0) {
m_parser_state = UTF8Needs3Bytes;
m_parser_codepoint = ch & 0x07;
return;
}
fail_utf8_parse();
return;
}
switch (ch) {
@ -925,21 +970,26 @@ void Terminal::on_input(u8 ch)
return;
}
on_codepoint(ch);
}
void Terminal::on_codepoint(u32 codepoint)
{
auto new_column = m_cursor_column + 1;
if (new_column < columns()) {
put_character_at(m_cursor_row, m_cursor_column, ch);
put_character_at(m_cursor_row, m_cursor_column, codepoint);
set_cursor(m_cursor_row, new_column);
return;
}
if (m_stomp) {
m_stomp = false;
newline();
put_character_at(m_cursor_row, m_cursor_column, codepoint);
set_cursor(m_cursor_row, 1);
} else {
if (m_stomp) {
m_stomp = false;
newline();
put_character_at(m_cursor_row, m_cursor_column, ch);
set_cursor(m_cursor_row, 1);
} else {
// Curious: We wait once on the right-hand side
m_stomp = true;
put_character_at(m_cursor_row, m_cursor_column, ch);
}
// Curious: We wait once on the right-hand side
m_stomp = true;
put_character_at(m_cursor_row, m_cursor_column, codepoint);
}
}

10
Libraries/LibVT/Terminal.h
View file

@ -101,6 +101,8 @@ public:
private:
typedef Vector<unsigned, 4> ParamVector;
void on_codepoint(u32);
void scroll_up();
void scroll_down();
void newline();
@ -171,7 +173,7 @@ private:
void execute_xterm_command();
void execute_hashtag(u8);
enum EscapeState {
enum ParserState {
Normal,
GotEscape,
ExpectParameter,
@ -180,9 +182,13 @@ private:
ExpectHashtagDigit,
ExpectXtermParameter,
ExpectStringTerminator,
UTF8Needs3Bytes,
UTF8Needs2Bytes,
UTF8Needs1Byte,
};
EscapeState m_parser_state { Normal };
ParserState m_parser_state { Normal };
u32 m_parser_codepoint { 0 };
Vector<u8> m_parameters;
Vector<u8> m_intermediates;
Vector<u8> m_xterm_parameters;