42 lines
1.2 KiB
Zig
Vendored
42 lines
1.2 KiB
Zig
Vendored
//! Copied from https://github.com/ziglang/zig/blob/6f0807f50f4e946bb850e746beaa5d6556cf7750/lib/std/unicode.zig
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//! with all safety checks removed. These functions must only be called with known-good buffers that have already
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//! been validated as being legitimate UTF8-encoded data, otherwise undefined behavior will occur.
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pub fn utf8ByteSequenceLength_unsafe(first_byte: u8) u3 {
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return switch (first_byte) {
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0b0000_0000...0b0111_1111 => 1,
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0b1100_0000...0b1101_1111 => 2,
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0b1110_0000...0b1110_1111 => 3,
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0b1111_0000...0b1111_0111 => 4,
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else => unreachable,
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};
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}
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pub fn utf8Decode2_unsafe(bytes: []const u8) u21 {
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var value: u21 = bytes[0] & 0b00011111;
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value <<= 6;
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return value | (bytes[1] & 0b00111111);
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}
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pub fn utf8Decode3_unsafe(bytes: []const u8) u21 {
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var value: u21 = bytes[0] & 0b00001111;
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value <<= 6;
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value |= bytes[1] & 0b00111111;
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value <<= 6;
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return value | (bytes[2] & 0b00111111);
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}
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pub fn utf8Decode4_unsafe(bytes: []const u8) u21 {
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var value: u21 = bytes[0] & 0b00000111;
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value <<= 6;
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value |= bytes[1] & 0b00111111;
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value <<= 6;
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value |= bytes[2] & 0b00111111;
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value <<= 6;
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return value | (bytes[3] & 0b00111111);
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}
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