58 lines
1.1 KiB
PHP
58 lines
1.1 KiB
PHP
type
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ByteString = String[2]; { String representing a u8. }
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ShortString = String[4]; { String representing a u16. }
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function ValidHexDigit(bval: Byte): Boolean;
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var
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IsValid : Boolean = False;
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begin
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if ((bval >= $30) and (bval <= $39)) then
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IsValid := True;
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if ((bval >= $41) and (bval <= $46)) then
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IsValid := True;
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if ((bval >= $61) and (bval <= $66)) then
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IsValid := True;
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ValidHexDigit := IsValid;
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end;
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function ReadDigit(bchr: Char): Byte;
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var
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bval : Byte = 0;
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label
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exitearly;
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begin
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bval := Byte(bchr);
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if (not ValidHexDigit(bval)) then
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begin
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bval := 0;
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goto exitearly;
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end;
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{Normalize downcase digits to upcase digits.}
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if (bchr >= 'a') then
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bval := bval xor $20;
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{Perform the conversion.}
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if (bchr >= 'A') then
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bval := (bval - $41) + 10
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else
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bval := bval - $30;
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exitearly:
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ReadDigit := bval;
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end;
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function ReadByte(bstr : ByteString): Byte;
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var
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out : Byte = 0;
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begin
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out := ReadDigit(bstr[1]) shl 4;
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out := out + ReadDigit(bstr[2]);
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ReadByte := out;
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end;
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