Base64 кодирование
01.01.2007
function Decode(const S: AnsiString): AnsiString;
const
Map: array[Char] of Byte = (0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 62, 0, 0, 0, 63, 52, 53,
54, 55, 56, 57, 58, 59, 60, 61, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2,
3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19,
20, 21, 22, 23, 24, 25, 0, 0, 0, 0, 0, 0, 26, 27, 28, 29, 30,
31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45,
46, 47, 48, 49, 50, 51, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0);
var
I: LongInt;
begin
case Length(S) of
2:
begin
I := Map[S[1]] + (Map[S[2]] shl 6);
SetLength(Result, 1);
Move(I, Result[1], Length(Result))
end;
3:
begin
I := Map[S[1]] + (Map[S[2]] shl 6) + (Map[S[3]] shl 12);
SetLength(Result, 2);
Move(I, Result[1], Length(Result))
end;
4:
begin
I := Map[S[1]] + (Map[S[2]] shl 6) + (Map[S[3]] shl 12) +
(Map[S[4]] shl 18);
SetLength(Result, 3);
Move(I, Result[1], Length(Result))
end
end
end;
function Encode(const S: AnsiString): AnsiString;
const
Map: array[0..63] of Char = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ' +
'abcdefghijklmnopqrstuvwxyz0123456789+/';
var
I: LongInt;
begin
I := 0;
Move(S[1], I, Length(S));
case Length(S) of
1:
Result := Map[I mod 64] + Map[(I shr 6) mod 64];
2:
Result := Map[I mod 64] + Map[(I shr 6) mod 64] +
Map[(I shr 12) mod 64];
3:
Result := Map[I mod 64] + Map[(I shr 6) mod 64] +
Map[(I shr 12) mod 64] + Map[(I shr 18) mod 64]
end
end;
Взято с сайта https://www.swissdelphicenter.ch/en/tipsindex.php
type TAByte = array [0..maxInt-1] of byte;
type TPAByte = ^TAByte;
function Encode(data:string) : string; overload;
const b64 : array [0..63] of char = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';
var ic,len : integer;
pi, po : TPAByte;
c1 : dword;
begin
len:=length(data);
if len > 0 then begin
SetLength(result, ((len + 2) div 3) * 4);
pi := pointer(data);
po := pointer(result);
for ic := 1 to len div 3 do begin
c1 := pi^[0] shl 16 + pi^[1] shl 8 + pi^[2];
po^[0] := byte(b64[(c1 shr 18) and $3f]);
po^[1] := byte(b64[(c1 shr 12) and $3f]);
po^[2] := byte(b64[(c1 shr 6) and $3f]);
po^[3] := byte(b64[(c1 ) and $3f]);
inc(dword(po), 4);
inc(dword(pi), 3);
end;
case len mod 3 of
1 : begin
c1 := pi^[0] shl 16;
po^[0] := byte(b64[(c1 shr 18) and $3f]);
po^[1] := byte(b64[(c1 shr 12) and $3f]);
po^[2] := byte('=');
po^[3] := byte('=');
end;
2 : begin
c1 := pi^[0] shl 16 + pi^[1] shl 8;
po^[0] := byte(b64[(c1 shr 18) and $3f]);
po^[1] := byte(b64[(c1 shr 12) and $3f]);
po^[2] := byte(b64[(c1 shr 6) and $3f]);
po^[3] := byte('=');
end;
end;
end else
result := '';
end;
function Decode(data:string) : string; overload;
var i1,i2,len : integer;
pi, po : TPAByte;
ch1 : char;
c1 : dword;
begin
len:=length(data);
if (len > 0) and (len mod 4 = 0) then begin
len := len shr 2;
SetLength(result, len * 3);
pi := pointer(data);
po := pointer(result);
for i1 := 1 to len do begin
c1 := 0;
i2 := 0;
while true do begin
ch1 := char(pi^[i2]);
case ch1 of
'A'..'Z' : c1 := c1 or (dword(ch1) - byte('A') );
'a'..'z' : c1 := c1 or (dword(ch1) - byte('a') + 26);
'0'..'9' : c1 := c1 or (dword(ch1) - byte('0') + 52);
'+' : c1 := c1 or 62;
'/' : c1 := c1 or 63;
else begin
if i2 = 3 then begin
po^[0] := c1 shr 16;
po^[1] := byte(c1 shr 8);
SetLength(result, Length(result) - 1);
end else begin
po^[0] := c1 shr 10;
SetLength(result, Length(result) - 2);
end;
exit;
end;
end;
if i2 = 3 then
break;
inc(i2);
c1 := c1 shl 6;
end;
po^[0] := c1 shr 16;
po^[1] := byte(c1 shr 8);
po^[2] := byte(c1);
inc(dword(pi), 4);
inc(dword(po), 3);
end;
end else
result := '';
end;
....
var a,b:string;
begin
a:='aaa';
b:=Encode( a );
showmessage( b );
a:=Decode( b );
showmessage( a );
const
Codes64 = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz+/';
function Encode64(S: string): string;
var
i: Integer;
a: Integer;
x: Integer;
b: Integer;
begin
Result := '';
a := 0;
b := 0;
for i := 1 to Length(s) do
begin
x := Ord(s[i]);
b := b * 256 + x;
a := a + 8;
while a >= 6 do
begin
a := a - 6;
x := b div (1 shl a);
b := b mod (1 shl a);
Result := Result + Codes64[x + 1];
end;
end;
if a > 0 then
begin
x := b shl (6 - a);
Result := Result + Codes64[x + 1];
end;
end;
const
Codes64 = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz+/';
function Decode64(S: string): string;
var
i: Integer;
a: Integer;
x: Integer;
b: Integer;
begin
Result := '';
a := 0;
b := 0;
for i := 1 to Length(s) do
begin
x := Pos(s[i], codes64) - 1;
if x >= 0 then
begin
b := b * 64 + x;
a := a + 6;
if a >= 8 then
begin
a := a - 8;
x := b shr a;
b := b mod (1 shl a);
x := x mod 256;
Result := Result + chr(x);
end;
end
else
Exit;
end;
end;
Взято с сайта https://www.swissdelphicenter.ch/en/tipsindex.php
{ 64-битное декодирование файлов }
{ Arne de Bruijn }
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.
DelphiWorld 6.0