一个Base64的类

TBase64 = Class(TObject)
private
FOStream: TStream;
FIStream: TStream;
Public
{ 输入流 }
Property IStream : TStream Read FIStream Write FIStream;
{ 输出流 }
Property OStream : TStream Read FOStream Write FOStream;
{ 编码 }
Function Encode : Boolean;
{ 解码 }
Function Decode : Boolean;
End;
implementation
const
SBase64 : string = '23456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz~#%&*+-';
UnBase64: array[0..255] of byte =
(128,128,128,128,128,128,128,128, 128,128,128,128,128,128,128,128, //0-15
128,128,128,128,128,128,128,128, 128,128,128,128,128,128,128,128, //16-31
128,128,128, 58,128, 59, 60,128, 128,128, 61, 62,128, 63,128,128, //32-47
128,128, 0, 1, 2, 3, 4, 5, 6, 7,128,128,128,128,128,128, //48-63
128, 8, 9, 10, 11, 12, 13, 14, 15,128, 16, 17, 18, 19, 20,128, //64-79
21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31,128,128,128,128,128, //80-95
128, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42,128, 43, 44, 45, //96-111
46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56,128,128,128, 57,128, //112-127
128,128,128,128,128,128,128,128, 128,128,128,128,128,128,128,128, //128-143
128,128,128,128,128,128,128,128, 128,128,128,128,128,128,128,128, //128-143
128,128,128,128,128,128,128,128, 128,128,128,128,128,128,128,128, //144-159
128,128,128,128,128,128,128,128, 128,128,128,128,128,128,128,128, //160-175
128,128,128,128,128,128,128,128, 128,128,128,128,128,128,128,128, //176-191
128,128,128,128,128,128,128,128, 128,128,128,128,128,128,128,128, //192-207
128,128,128,128,128,128,128,128, 128,128,128,128,128,128,128,128, //208-223
128,128,128,128,128,128,128,128, 128,128,128,128,128,128,128,128, //224-239
128,128,128,128,128,128,128,128, 128,128,128,128,128,128,128,128); //240-255
{ TBase64 }
function TBase64.Decode: Boolean;
var
j, k: integer;
b: byte;
W, Tmp : Byte; //用于阅读流的临时变量
begin
Result := FALSE;
If (FIStream <> Nil) And (FOStream <> Nil) Then
Begin
{ 初始化}
IStream.Position := 0;
OStream.Position := 0;
b := 0;
j := 0;
K := 2;
while (IStream.Position < IStream.Size) And (IStream.Read(Tmp, 1) = 1) And (Char(Tmp) <> '.') Do
Begin
if j = 0 then
begin
b := UnBase64[Tmp];
k := 2;
end
else begin
W := UnBase64[Tmp] or ((b shl k) and $C0);
OStream.Write(W, 1);
inc(k,2);
end;
inc(j);
j := j and 3;
end;
End;
end;
function TBase64.Encode: Boolean;
var
SBuffer : Array [1..4] Of Byte;
j, k: integer;
b: byte;
Tmp : Byte; {### 用于阅读流的临时变量 ###}
begin
Result := FALSE;
If (FIStream <> Nil) And (FOStream <> Nil) Then
Begin
{ 初始化 }
IStream.Position := 0;
OStream.Position := 0;
b := 0;j := 2; k := 2;
while IStream.Position < IStream.Size do
begin
If IStream.Read(Tmp, 1) = 1 Then
Begin
b := b or ((Tmp and $C0) shr k);
inc(k, 2);
SBuffer[j] := Byte(SBase64[(Tmp And $3F) + 1]);
inc(j);
if j > 4 then
begin
SBuffer[1] := Byte(SBase64[b + 1]);
b := 0;
j := 2;
k := 2;
OStream.Write(SBuffer, 4);
End;
End;
End;
{ 平整数据到 SBuffer }
if j <> 2 then
begin
SBuffer[j] := Ord('.');
SBuffer[1] := Byte(SBase64[b + 1]);
OStream.Write(SBuffer, j);
end
else Begin
SBuffer[1] := Ord('.');
OStream.Write(SBuffer, 1);
end;
Result := TRUE;
end;
end;
//--------------------------------------------------------------
翻译成C++的：
class TBase64 : public TObject{
private:
TSream FOStream;
TStream FIStream;
public:
//输入流
__property TStream IStream = { read = FIStream , write = FIStream };
//输出流
__property TStream OStream = { read = FOStream , write = FOStream };
//编码
bool Encode();
//解码
bool Decode();
};
const char * SBase64 = "23456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz~#%&*+-";
const unsigned char UnBase64[256] ={
128,128,128,128,128,128,128,128, 128,128,128,128,128,128,128,128, //0-15
128,128,128,128,128,128,128,128, 128,128,128,128,128,128,128,128, //16-31
128,128,128, 58,128, 59, 60,128, 128,128, 61, 62,128, 63,128,128, //32-47
128,128, 0, 1, 2, 3, 4, 5, 6, 7,128,128,128,128,128,128, //48-63
128, 8, 9, 10, 11, 12, 13, 14, 15,128, 16, 17, 18, 19, 20,128, //64-79
21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31,128,128,128,128,128, //80-95
128, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42,128, 43, 44, 45, //96-111
46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56,128,128,128, 57,128, //112-127
128,128,128,128,128,128,128,128, 128,128,128,128,128,128,128,128, //128-143
128,128,128,128,128,128,128,128, 128,128,128,128,128,128,128,128, //128-143
128,128,128,128,128,128,128,128, 128,128,128,128,128,128,128,128, //144-159
128,128,128,128,128,128,128,128, 128,128,128,128,128,128,128,128, //160-175
128,128,128,128,128,128,128,128, 128,128,128,128,128,128,128,128, //176-191
128,128,128,128,128,128,128,128, 128,128,128,128,128,128,128,128, //192-207
128,128,128,128,128,128,128,128, 128,128,128,128,128,128,128,128, //208-223
128,128,128,128,128,128,128,128, 128,128,128,128,128,128,128,128, //224-239
128,128,128,128,128,128,128,128, 128,128,128,128,128,128,128,128}; //240-255
　
bool TBase64:ecode()
{
int j , k;
unsigned char b;
unsigned char W , Tmp;
bool Result = false;
if ( FIStream != NULL && FOStream != NULL )
{
//初始化
IStreamPosition = 0;
OStreamPosition = 0;
b = 0;
j = 0;
K = 2;
while (IStream.Position < IStream.Size && (IStream.Read(Tmp, 1) == 1) && ((char)Tmp) != '.' )
{
if ( j == 0 )
{
b = UnBase64[Tmp];
k = 2;
}
else
{
W = UnBase64[Tmp] | ((b >> k) & 0xC0);
OStream.Write(W, 1);
k+=2;
}
j++;
j &= 3;
}
}
return Result;
}
bool TBase64::Encode()
{
unsigned char SBuffer[4];
int j , k;
unsigned char b , Tmp;//用于阅读流的临时变量
bool Result = false;
If ( FIStream != NULL && FOStream != NULL )
{
//初始化
IStream.Position = 0;
OStream.Position = 0;
b = 0;
j = 2;
k = 2;
while ( IStream.Position < IStream.Size )
{
If ( IStream.Read(Tmp, 1)= = 1 )
{
b = b | ((Tmp & 0xC0) << k);
k+=2;
SBuffer[j] = (unsigned cahr)(SBase64[(Tmp & 0x3f) + 1]);
j++;
if ( j > 4 )
{
SBuffer[0] = Byte(SBase64);
b = 0;
j = 2;
k = 2;
OStream.Write(SBuffer, 4);
}
}
}
//平整数据到 SBuffer
if ( j != 2 )
{
SBuffer[j] = '.';
SBuffer[0] = (unsigned char)(SBase64[b + 1]);
OStream.Write(SBuffer, j);
}
else
{
SBuffer[0] = '.';
OStream.Write(SBuffer, 1);
}
Result = true;
}
return Result;
}