base64加密函数.txt

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function Base64Encode(const s: string): string;
var
s4: string;
i, j, k: integer;
b: byte;
const
Base64: string = '23456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz~#%&*+-';
begin
Result := '';
SetLength(s4, 4);
b := 0;
i := 1;
j := 2;
k := 2;
while i <= length(s) do
begin
b := b or ((ord(s[i]) and $C0) shr k);
inc(k,2);
s4[j] := Base64[(ord(s[i]) and $3F)+1];
inc(i);
inc(j);
if j > 4 then
begin
s4[1] := Base64[b+1];
b := 0;
j := 2;
k := 2;
Result := Result + s4;
end;
end;
if j <> 2 then
begin // Flush data in s4.
s4[j] := '.';
s4[1] := Base64[b+1];
Result := Result + s4;
SetLength(Result, Length(Result) - (4 - j));
end else
Result := Result + '.';
end;