22 lines
834 B
Text
22 lines
834 B
Text
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# input: an array of decimal integers representing the utf-8 bytes of a Unicode codepoint.
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# output: the corresponding decimal number of that codepoint.
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def utf8_encode:
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def lpad($width): [(range(0;8)|0), .[]][- $width:];
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def multibyte: [1,0, (.[-6: ]|lpad(6))[]];
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def firstOf2: [1,1,0, (.[: -6]|lpad(5))[]];
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def firstOf3: [1,1,1,0, (.[:-12]|lpad(4))[]];
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def firstOf4: [1,1,1,1,0, (.[:-18]|lpad(3))[]];
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. as $n
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| binary_digits
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| length as $len
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| if $len <8 then [$n]
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else if $len <= 12 then [ firstOf2, multibyte ]
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elif $len <= 16 then [ firstOf3, (.[:-6] | multibyte), multibyte ]
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else [firstOf4,
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(.[ :-12] | multibyte),
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(.[-12: -6] | multibyte),
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multibyte]
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end
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| map(binary_to_decimal)
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end;
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