发信人: delphilxh(先锋)
整理人: soaringbird(2001-07-03 09:40:09), 站内信件
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//*************************************************************************
//对Base64编码进行解码
const
Base64In: TLookup = (
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, 62, 255, 255, 255, 63, 52, 53, 54, 55,
56, 57, 58, 59, 60, 61, 255, 255, 255, 64, 255, 255, 255,
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,
255, 255, 255, 255, 255, 255, 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, 255, 255, 255, 255, 255
);
function Base64(FCurrentData:string):string;
var
ByteCount : Integer;
SourceIndex : Integer;
DataOut,dee : array[0..2] of Byte;
DataIn0 : Byte;
DataIn1 : Byte;
DataIn2 : Byte;
DataIn3 : Byte;
I : Integer;
str :string;
begin
Result:='';
{ 跳过空格 }
SourceIndex := 1;
while (FCurrentData[SourceIndex] <> #0) and (FCurrentData[SourceIndex] = ' ') do
Inc(SourceIndex);
//开始进行解码
while (FCurrentData[SourceIndex] <> #0) and (FCurrentData[SourceIndex] <> ' ') do
begin
DataIn0 := Base64In[Byte(FCurrentData[SourceIndex + 0])];
DataIn1 := Base64In[Byte(FCurrentData[SourceIndex + 1])];
DataIn2 := Base64In[Byte(FCurrentData[SourceIndex + 2])];
DataIn3 := Base64In[Byte(FCurrentData[SourceIndex + 3])];
DataOut[0] := (DataIn0 and $3F) shl 2 + (DataIn1 and $30) shr 4;
if DataIn2 <> $40 then
begin
DataOut[1] := (DataIn1 and $0F) shl 4 + (DataIn2 and $3C) shr 2;
if DataIn3 <> $40 then
begin
DataOut[2] := (DataIn2 and $03) shl 6 + (DataIn3 and $3F);
ByteCount := 3;
end
else
ByteCount := 2;
end
else
ByteCount := 1;
for i:=0 to ByteCount-1 do
Result:=Result+chr(dataOut[i]);
// DecodedIndex := DecodedIndex + ByteCount;
SourceIndex := SourceIndex + 4;
end;
end;
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