difftastic/vendored_parsers/tree-sitter-hare/example/rune.ha

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use types;
const masks: [_]u8 = [0x7F, 0x1F, 0x0F, 0x07, 0x03, 0x01];
type rsize = struct {
mask: u8,
result: u8,
octets: size,
};
const sizes: [_]rsize = [
rsize { mask = 0x80, result = 0x00, octets = 1 },
rsize { mask = 0xE0, result = 0xC0, octets = 2 },
rsize { mask = 0xF0, result = 0xE0, octets = 3 },
rsize { mask = 0xF8, result = 0xF0, octets = 4 },
rsize { mask = 0xFC, result = 0xF8, octets = 5 },
rsize { mask = 0xFE, result = 0xF8, octets = 6 },
];
// Returns the size of a rune, in octets, when encoded as UTF-8.
export fn runesz(r: rune) size = {
const ch = r: u32;
return if (ch < 0x80) 1
else if (ch < 0x800) 2
else if (ch < 0x10000) 3
else 4;
};