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use lib::*; const TAG_CONT: u8 = 0b1000_0000; const TAG_TWO_B: u8 = 0b1100_0000; const TAG_THREE_B: u8 = 0b1110_0000; const TAG_FOUR_B: u8 = 0b1111_0000; const MAX_ONE_B: u32 = 0x80; const MAX_TWO_B: u32 = 0x800; const MAX_THREE_B: u32 = 0x10000; #[inline] pub fn encode(c: char) -> Encode { let code = c as u32; let mut buf = [0; 4]; let pos = if code < MAX_ONE_B { buf[3] = code as u8; 3 } else if code < MAX_TWO_B { buf[2] = (code >> 6 & 0x1F) as u8 | TAG_TWO_B; buf[3] = (code & 0x3F) as u8 | TAG_CONT; 2 } else if code < MAX_THREE_B { buf[1] = (code >> 12 & 0x0F) as u8 | TAG_THREE_B; buf[2] = (code >> 6 & 0x3F) as u8 | TAG_CONT; buf[3] = (code & 0x3F) as u8 | TAG_CONT; 1 } else { buf[0] = (code >> 18 & 0x07) as u8 | TAG_FOUR_B; buf[1] = (code >> 12 & 0x3F) as u8 | TAG_CONT; buf[2] = (code >> 6 & 0x3F) as u8 | TAG_CONT; buf[3] = (code & 0x3F) as u8 | TAG_CONT; 0 }; Encode { buf: buf, pos: pos } } pub struct Encode { buf: [u8; 4], pos: usize, } impl Encode { pub fn as_str(&self) -> &str { str::from_utf8(&self.buf[self.pos..]).unwrap() } }