64-битное кодирование
uses dos;
var
Base64: array[43..122] of byte;
var
T: text;
Chars: set of char;
S: string;
K, I, J: word;
Buf: pointer;
DShift: integer;
F: file;
B, B1: byte;
Decode: array[0..63] of byte;
Shift2: byte;
Size, W: word;
begin
FillChar(Base64, SizeOf(Base64), 255);
J := 0;
for I := 65 to 90 do
begin
Base64[I] := J;
Inc(J);
end;
for I := 97 to 122 do
begin
Base64[I] := J;
Inc(J);
end;
for I := 48 to 57 do
begin
Base64[I] := J;
Inc(J);
end;
Base64[43] := J;
Inc(J);
Base64[47] := J;
Inc(J);
if ParamCount = 0 then
begin
WriteLn('UNBASE64 <mime-файл> [<выходной файл>]'); Halt(1);
end;
S := ParamStr(1);
assign(T, S);
GetMem(Buf, 32768);
SetTextBuf(T, Buf^, 32768);
{$I-}reset(T);
{$I+}
if IOResult <> 0 then
begin
WriteLn('Ошибка считывания ', S);
Halt(1); end;
if ParamCount >= 2 then
S := ParamStr(2)
else
begin
write('Расположение:'); ReadLn(S);
end;
assign(F, S);
{$I-}rewrite(F, 1);
{$I+}
if IOResult <> 0 then
begin
WriteLn('Ошибка создания ', S); Halt(1);
end;
while not eof(T) do
begin
ReadLn(T, S);
if (S <> '') and (pos(' ', S) = 0) and (S[1] >= #43) and (S[1] <= #122) and
(Base64[byte(S[1])] <> 255) then
begin
FillChar(Decode, SizeOf(Decode), 0);
DShift := 0;
J := 0;
Shift2 := 1;
Size := 255;
B := 0;
for I := 1 to Length(S) do
begin
case S[I] of
#43..#122: B1 := Base64[Ord(S[I])];
else
B1 := 255;
end;
if B1 = 255 then
if S[I] = '=' then
begin
B1 := 0;
if Size = 255 then
Size := J;
end
else
WriteLn('Ошибка символа:', S[I], ' (', Ord(S[I]), ')'); if DShift and 7 = 0 then
begin
Decode[J] := byte(B1 shl 2);
DShift := 2;
end
else
begin
Decode[J] := Decode[J] or Hi(word(B1) shl (DShift + 2));
Decode[J + 1] := Lo(word(B1) shl (DShift + 2));
Inc(J);
Inc(DShift, 2);
end;
end;
if Size = 255 then
Size := J;
BlockWrite(F, Decode, Size);
end;
end;
Close(F);
close(T);
end. |
