Hojun-Cho
e9c3f75fd1
Both used the -1 sentinel return; both had no external callers, so the graduation is purely the API-shape change. utf8.runesz uses void for "rune outside legal range"; bufio.readbyte uses void for EOF (empty buffer). The full Hare shapes ((size | invalid) and (u8 | EOF | io::error)) are still richer than this — those richer returns arrive when utf8 grows an explicit invalid type and bufio wires through io::stream's error path.
16 lines
518 B
Plaintext
16 lines
518 B
Plaintext
// encoding/utf8 — UTF-8 helpers. RFC 3629; we only handle the legal
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// subset (no over-long encodings, no surrogates).
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def MAX: rune = 1114111; // 0x10FFFF
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// runesz — encoded byte length of `r` as UTF-8. void variant means
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// `r` is outside the legal range (negative, > 0x10FFFF).
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export fn runesz(r: rune) (i32 | void) = {
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if (r < 0) { return; };
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if (r < 128) { return 1; };
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if (r < 2048) { return 2; };
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if (r < 65536) { return 3; };
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if (r <= MAX) { return 4; };
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return;
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};
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