charWidth function
Returns the terminal display width of a Unicode code point.
Returns 2 for CJK characters and emoji, 1 for everything else.
Implementation
int charWidth(int rune) {
if (rune < 0x7F) return 1;
if (rune >= 0x1100 &&
(rune <= 0x115F ||
rune == 0x2329 ||
rune == 0x232A ||
(rune >= 0x2E00 && rune <= 0xA4CF && rune != 0x303F) ||
(rune >= 0xAC00 && rune <= 0xD7A3) ||
(rune >= 0xF900 && rune <= 0xFAFF) ||
(rune >= 0xFE10 && rune <= 0xFE19) ||
(rune >= 0xFE30 && rune <= 0xFE6F) ||
(rune >= 0xFF01 && rune <= 0xFF60) ||
(rune >= 0xFFE0 && rune <= 0xFFE6) ||
(rune >= 0x1B000 && rune <= 0x1B0FF) ||
(rune >= 0x1B100 && rune <= 0x1B12F) ||
(rune >= 0x1F004) ||
(rune >= 0x1F0CF) ||
(rune >= 0x1F18E) ||
(rune >= 0x1F191 && rune <= 0x1F1FF) ||
(rune >= 0x1F200 && rune <= 0x1F2FF) ||
(rune >= 0x1F300 && rune <= 0x1F5FF) ||
(rune >= 0x1F600 && rune <= 0x1F64F) ||
(rune >= 0x1F680 && rune <= 0x1F6FF) ||
(rune >= 0x1F900 && rune <= 0x1F9FF) ||
(rune >= 0x20000 && rune <= 0x2FFFD) ||
(rune >= 0x30000 && rune <= 0x3FFFD))) {
return 2;
}
return 1;
}