{******************************************************************************}
{ }
{ Project JEDI Code Library (JCL) }
{ }
{ The contents of this file are subject to the Mozilla Public License Version }
{ 1.1 (the "License"); you may not use this file except in compliance with the }
{ License. You may obtain a copy of the License at http://www.mozilla.org/MPL/ }
{ }
{ Software distributed under the License is distributed on an "AS IS" basis, }
{ WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License for }
{ the specific language governing rights and limitations under the License. }
{ }
{ The Original Code is JclMime.pas. }
{ }
{ The Initial Developer of the Original Code is documented in the accompanying }
{ help file JCL.chm. Portions created by these individuals are Copyright (C) }
{ 2000 of these individuals. }
{ }
{******************************************************************************}
{ }
{ Lightening fast Mime (Base64) Encoding and Decoding routines. Coded by Ralf }
{ Junker (ralfjunker@gmx.de). }
{ }
{ Unit owner: Marcel van Brakel }
{ Last modified: January 29, 2001 }
{ }
{******************************************************************************}
unit JclMime;
{$I jcl.inc}
{$WEAKPACKAGEUNIT ON}
interface
uses
Classes, SysUtils;
function MimeEncodeString(const S: AnsiString): AnsiString;
function MimeDecodeString(const S: AnsiString): AnsiString;
procedure MimeEncodeStream(const InputStream: TStream; const OutputStream: TStream);
procedure MimeDecodeStream(const InputStream: TStream; const OutputStream: TStream);
function MimeEncodedSize(const I: Cardinal): Cardinal;
function MimeDecodedSize(const I: Cardinal): Cardinal;
procedure MimeEncode(var InputBuffer; const InputByteCount: Cardinal; var OutputBuffer);
function MimeDecode(var InputBuffer; const InputBytesCount: Cardinal; var OutputBuffer): Cardinal;
function MimeDecodePartial(var InputBuffer; const InputBytesCount: Cardinal;
var OutputBuffer; var ByteBuffer: Cardinal; var ByteBufferSpace: Cardinal): Cardinal;
function MimeDecodePartialEnd(var OutputBuffer; const ByteBuffer: Cardinal;
const ByteBufferSpace: Cardinal): Cardinal;
implementation
// Caution: For MimeEncodeStream and all other kinds of multi-buffered
// Mime encodings (i.e. Files etc.), BufferSize must be set to a multiple of 3.
// Even though the implementation of the Mime decoding routines below
// do not require a particular buffer size, they work fastest with sizes of
// multiples of four. The chosen size is a multiple of 3 and of 4 as well.
// The following numbers are, in addition, also divisible by 1024:
// $2400, $3000, $3C00, $4800, $5400, $6000, $6C00.
const
BUFFER_SIZE = $3000;
EqualSign = Byte('=');
MIME_ENCODE_TABLE: array [0..63] of Byte = (
65, 66, 67, 68, 69, 70, 71, 72, // 00 - 07
73, 74, 75, 76, 77, 78, 79, 80, // 08 - 15
81, 82, 83, 84, 85, 86, 87, 88, // 16 - 23
89, 90, 97, 98, 99, 100, 101, 102, // 24 - 31
103, 104, 105, 106, 107, 108, 109, 110, // 32 - 39
111, 112, 113, 114, 115, 116, 117, 118, // 40 - 47
119, 120, 121, 122, 48, 49, 50, 51, // 48 - 55
52, 53, 54, 55, 56, 57, 43, 47); // 56 - 63
MIME_DECODE_TABLE: array [Byte] of Cardinal = (
255, 255, 255, 255, 255, 255, 255, 255, // 00 - 07
255, 255, 255, 255, 255, 255, 255, 255, // 08 - 15
255, 255, 255, 255, 255, 255, 255, 255, // 16 - 23
255, 255, 255, 255, 255, 255, 255, 255, // 24 - 31
255, 255, 255, 255, 255, 255, 255, 255, // 32 - 39
255, 255, 255, 62, 255, 255, 255, 63, // 40 - 47
52, 53, 54, 55, 56, 57, 58, 59, // 48 - 55
60, 61, 255, 255, 255, 255, 255, 255, // 56 - 63
255, 0, 1, 2, 3, 4, 5, 6, // 64 - 71
7, 8, 9, 10, 11, 12, 13, 14, // 72 - 79
15, 16, 17, 18, 19, 20, 21, 22, // 80 - 87
23, 24, 25, 255, 255, 255, 255, 255, // 88 - 95
255, 26, 27, 28, 29, 30, 31, 32, // 96 - 103
33, 34, 35, 36, 37, 38, 39, 40, // 104 - 111
41, 42, 43, 44, 45, 46, 47, 48, // 112 - 119
49, 50, 51, 255, 255, 255, 255, 255, // 120 - 127
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255);
type
PByte4 = ^TByte4;
TByte4 = packed record
B1: Byte;
B2: Byte;
B3: Byte;
B4: Byte;
end;
PByte3 = ^TByte3;
TByte3 = packed record
B1: Byte;
B2: Byte;
B3: Byte;
end;
//------------------------------------------------------------------------------
// Wrapper functions & procedures
//------------------------------------------------------------------------------
function MimeEncodeString(const S: AnsiString): AnsiString;
var
L: Cardinal;
begin
L := Length(S);
if L > 0 then
begin
SetLength(Result, MimeEncodedSize(L));
MimeEncode(PChar(S)^, L, PChar(Result)^);
end
else
Result := '';
end;
//------------------------------------------------------------------------------
function MimeDecodeString(const S: AnsiString): AnsiString;
var
ByteBuffer, ByteBufferSpace: Cardinal;
L: Cardinal;
begin
L := Length(S);
if L > 0 then
begin
SetLength(Result, MimeDecodedSize(L));
ByteBuffer := 0;
ByteBufferSpace := 4;
L := MimeDecodePartial(PChar(S)^, L, PChar(Result)^, ByteBuffer, ByteBufferSpace);
Inc(L, MimeDecodePartialEnd(PChar(Cardinal(Result) + L)^, ByteBuffer, ByteBufferSpace));
SetLength(Result, L);
end;
end;
//------------------------------------------------------------------------------
procedure MimeEncodeStream(const InputStream: TStream; const OutputStream: TStream);
var
InputBuffer: array [0..BUFFER_SIZE - 1] of Byte;
OutputBuffer: array [0..((BUFFER_SIZE + 2) div 3) * 4 - 1] of Byte;
BytesRead: Integer;
begin
BytesRead := InputStream.Read(InputBuffer, SizeOf(InputBuffer));
while BytesRead > 0 do
begin
MimeEncode(InputBuffer, BytesRead, OutputBuffer);
OutputStream.Write(OutputBuffer, MimeEncodedSize(BytesRead));
BytesRead := InputStream.Read(InputBuffer, SizeOf(InputBuffer));
end;
end;
//------------------------------------------------------------------------------
procedure MimeDecodeStream(const InputStream: TStream; const OutputStream: TStream);
var
ByteBuffer, ByteBufferSpace: Cardinal;
InputBuffer: array [0..(BUFFER_SIZE + 3) div 4 * 3 - 1] of Byte;
OutputBuffer: array [0..BUFFER_SIZE - 1] of Byte;
BytesRead: Integer;
begin
ByteBuffer := 0;
ByteBufferSpace := 4;
BytesRead := InputStream.Read(InputBuffer, SizeOf(InputBuffer));
while BytesRead > 0 do
begin
OutputStream.Write(OutputBuffer, MimeDecodePartial(InputBuffer, BytesRead, OutputBuffer, ByteBuffer, ByteBufferSpace));
BytesRead := InputStream.Read(InputBuffer, SizeOf(InputBuffer));
end;
OutputStream.Write(OutputBuffer, MimeDecodePartialEnd(OutputBuffer, ByteBuffer, ByteBufferSpace));
end;
//------------------------------------------------------------------------------
// Helper functions
//------------------------------------------------------------------------------
function MimeEncodedSize(const I: Cardinal): Cardinal;
begin
Result := (I + 2) div 3 * 4;
end;
//------------------------------------------------------------------------------
function MimeDecodedSize(const I: Cardinal): Cardinal;
begin
Result := (I + 3) div 4 * 3;
end;
//------------------------------------------------------------------------------
// Primary functions & procedures
//------------------------------------------------------------------------------
procedure MimeEncode(var InputBuffer; const InputByteCount: Cardinal; var OutputBuffer);
var
B: Cardinal;
InMax3: Cardinal;
InPtr, InLimitPtr: ^Byte;
OutPtr: PByte4;
begin
if InputByteCount <= 0 then
Exit;
InPtr := @InputBuffer;
InMax3 := InputByteCount div 3 * 3;
OutPTr := @OutputBuffer;
Cardinal(InLimitPtr) := Cardinal(InPtr) + InMax3;
while InPtr <> InLimitPtr do
begin
B := InPtr^;
B := B shl 8;
Inc(InPtr);
B := B or InPtr^;
B := B shl 8;
Inc(InPtr);
B := B or InPtr^;
Inc(InPtr);
// Write 4 bytes to OutputBuffer (in reverse order).
OutPtr.B4 := MIME_ENCODE_TABLE[B and $3F];
B := B shr 6;
OutPtr.B3 := MIME_ENCODE_TABLE[B and $3F];
B := B shr 6;
OutPtr.B2 := MIME_ENCODE_TABLE[B and $3F];
B := B shr 6;
OutPtr.B1 := MIME_ENCODE_TABLE[B];
Inc(OutPtr);
end;
case InputByteCount - InMax3 of
1:
begin
B := InPtr^;
B := B shl 4;
OutPtr.B2 := MIME_ENCODE_TABLE[B and $3F];
B := B shr 6;
OutPtr.B1 := MIME_ENCODE_TABLE[B];
OutPtr.B3 := EqualSign; // Fill remaining 2 bytes.
OutPtr.B4 := EqualSign;
end;
2:
begin
B := InPtr^;
Inc(InPtr);
B := B shl 8;
B := B or InPtr^;
B := B shl 2;
OutPtr.B3 := MIME_ENCODE_TABLE[B and $3F];
B := B shr 6;
OutPTr.b2 := MIME_ENCODE_TABLE[B and $3F];
B := B shr 6;
OutPtr.B1 := MIME_ENCODE_TABLE[B];
OutPtr.B4 := EqualSign; // Fill remaining byte.
end;
end;
end;
//------------------------------------------------------------------------------
function MimeDecode(var InputBuffer; const InputBytesCount: Cardinal; var OutputBuffer): Cardinal;
var
ByteBuffer, ByteBufferSpace: Cardinal;
begin
ByteBuffer := 0;
ByteBufferSpace := 4;
Result := MimeDecodePartial(InputBuffer, InputBytesCount, OutputBuffer, ByteBuffer, ByteBufferSpace);
Inc(Result, MimeDecodePartialEnd(PChar(Cardinal(OutputBuffer) + Result)^, ByteBuffer, ByteBufferSpace));
end;
//------------------------------------------------------------------------------
function MimeDecodePartial(var InputBuffer; const InputBytesCount: Cardinal;
var OutputBuffer; var ByteBuffer: Cardinal; var ByteBufferSpace: Cardinal): Cardinal;
var
lByteBuffer, lByteBufferSpace, C: Cardinal;
InPtr, InLimitPtr: ^Byte;
OutPtr: PByte3;
begin
if InputBytesCount > 0 then
begin
InPtr := @InputBuffer;
Cardinal(InLimitPtr) := Cardinal(InPtr) + InputBytesCount;
OutPtr := @OutputBuffer;
lByteBuffer := ByteBuffer;
lByteBufferSpace := ByteBufferSpace;
while InPtr <> InLimitPtr do
begin
C := MIME_DECODE_TABLE[InPtr^]; // Read from InputBuffer.
Inc(InPtr);
if C = $FF then
Continue;
lByteBuffer := lByteBuffer shl 6;
lByteBuffer := lByteBuffer or C;
Dec(lByteBufferSpace);
if lByteBufferSpace <> 0 then
Continue; // Read 4 bytes from InputBuffer?
OutPtr.B3 := Byte(lByteBuffer); // Write 3 bytes to OutputBuffer (in reverse order).
lByteBuffer := lByteBuffer shr 8;
OutPtr.B2 := Byte(lByteBuffer);
lByteBuffer := lByteBuffer shr 8;
OutPtr.B1 := Byte(lByteBuffer);
lByteBuffer := 0;
Inc(OutPtr);
lByteBufferSpace := 4;
end;
ByteBuffer := lByteBuffer;
ByteBufferSpace := lByteBufferSpace;
Result := Cardinal(OutPtr) - Cardinal(@OutputBuffer);
end
else
Result := 0;
end;
//------------------------------------------------------------------------------
function MimeDecodePartialEnd(var OutputBuffer; const ByteBuffer: Cardinal;
const ByteBufferSpace: Cardinal): Cardinal;
var
lByteBuffer: Cardinal;
begin
case ByteBufferSpace of
1:
begin
lByteBuffer := ByteBuffer shr 2;
PByte3(@OutputBuffer).B2 := Byte(lByteBuffer);
lByteBuffer := lByteBuffer shr 8;
PByte3(@OutputBuffer).B1 := Byte(lByteBuffer);
Result := 2;
end;
2:
begin
lByteBuffer := ByteBuffer shr 4;
PByte3(@OutputBuffer).B1 := Byte(lByteBuffer);
Result := 1;
end;
else
Result := 0;
end;
end;
end.