里面是正常的base64算法，我想写成dll的，并切使用delphi 来调用他，该怎样写，我看写dll的例子都是 integer的 怎么没有string的类型的

里面是正常的base64算法，我想写成dll的，并切使用delphi 来调用他，该怎样写，我看写dll的例子都是 integer的 怎么没有string的类型的呢，调试还不能通过，请大家帮帮忙，(50分)<br />unit Unit1;

interface

uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls;
const
//BaseTable为BASE64码表
BaseTable:string='ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=';

type
TForm1 = class(TForm)
Edit1: TEdit;
Edit2: TEdit;
Edit3: TEdit;
Button1: TButton;
Button2: TButton;
procedure Button1Click(Sender: TObject);
procedure Button2Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;
function DecodeBase64(Source:string):string;
function EncodeBase64(Source:string):string;
function FindInTable(CSource:char):integer;
var
Form1: TForm1;

implementation

{$R *.dfm}
function FindInTable(CSource:char):integer;
begin
result:=Pos(string(CSource),BaseTable)-1;
end;

//编码函数
function EncodeBase64(Source:string):string;
var
Times,LenSrc,i:integer;
x1,x2,x3,x4:char;
xt:byte;
begin
result:='';
LenSrc:=length(Source);
if LenSrc mod 3 =0 then Times:=LenSrc div 3
else Times:=LenSrc div 3 + 1;
for i:=0 to times-1 do
begin
if LenSrc >= (3+i*3) then
begin
x1:=BaseTable[(ord(Source[1+i*3]) shr 2)+1];
xt:=(ord(Source[1+i*3]) shl 4) and 48;
xt:=xt or (ord(Source[2+i*3]) shr 4);
x2:=BaseTable[xt+1];
xt:=(Ord(Source[2+i*3]) shl 2) and 60;
xt:=xt or (ord(Source[3+i*3]) shr 6);
x3:=BaseTable[xt+1];
xt:=(ord(Source[3+i*3]) and 63);
x4:=BaseTable[xt+1];
end
else if LenSrc>=(2+i*3) then
begin
x1:=BaseTable[(ord(Source[1+i*3]) shr 2)+1];
xt:=(ord(Source[1+i*3]) shl 4) and 48;
xt:=xt or (ord(Source[2+i*3]) shr 4);
x2:=BaseTable[xt+1];
xt:=(ord(Source[2+i*3]) shl 2) and 60;
x3:=BaseTable[xt+1];
x4:='=';
end else
begin
x1:=BaseTable[(ord(Source[1+i*3]) shr 2)+1];
xt:=(ord(Source[1+i*3]) shl 4) and 48;
x2:=BaseTable[xt+1];
x3:='=';
x4:='=';
end;
result:=result+x1+x2+x3+x4;
end;
end;

//解码函数
function DecodeBase64(Source:string):string;
var
SrcLen,Times,i:integer;
x1,x2,x3,x4,xt:byte;
begin
result:='';
SrcLen:=Length(Source);
Times:=SrcLen div 4;
for i:=0 to Times-1 do
begin
x1:=FindInTable(Source[1+i*4]);
x2:=FindInTable(Source[2+i*4]);
x3:=FindInTable(Source[3+i*4]);
x4:=FindInTable(Source[4+i*4]);
x1:=x1 shl 2;
xt:=x2 shr 4;
x1:=x1 or xt;
x2:=x2 shl 4;
result:=result+chr(x1);
if x3= 64 then break;
xt:=x3 shr 2;
x2:=x2 or xt;
x3:=x3 shl 6;
result:=result+chr(x2);
if x4=64 then break;
x3:=x3 or x4;
result:=result+chr(x3);
end;
end;


procedure TForm1.Button1Click(Sender: TObject);
begin
edit2.text:=EncodeBase64(edit1.text);
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
edit3.text:=DecodeBase64 (edit2.text);
end;

end.

不能用string要用pchar

那返回值呢 ？？？pchar 可不行啊

可以啊，反回后再强制转换一下。

改成，widestring也可以

我弄好了 谢谢了楼上的几个朋友 。


建议以后的例子程序啊别整没有太大价值的东西，弄点实用的。
这个是我的dll 的能够使用的代码
library Project2;

{ Important note about DLL memory management: ShareMem must be the
first unit in your library's USES clause AND your project's (select
Project-View Source) USES clause if your DLL exports any procedures or
functions that pass strings as parameters or function results. This
applies to all strings passed to and from your DLL--even those that
are nested in records and classes. ShareMem is the interface unit to
the BORLNDMM.DLL shared memory manager, which must be deployed along
with your DLL. To avoid using BORLNDMM.DLL, pass string information
using PChar or ShortString parameters. }

uses
ShareMem,
SysUtils,
Classes;
const
//BaseTable为BASE64码表
BaseTable:string='ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=';
{$R *.res}
function FindInTable(CSource:char):integer;stdcall;
begin
result:=Pos(string(CSource),BaseTable)-1;
end;

//编码函数
function EncodeBase64(Source:ShortString):ShortString;stdcall;
var
Times,LenSrc,i:integer;
x1,x2,x3,x4:char;
xt:byte;
begin
result:='';
LenSrc:=length(Source);
if LenSrc mod 3 =0 then Times:=LenSrc div 3
else Times:=LenSrc div 3 + 1;
for i:=0 to times-1 do
begin
if LenSrc >= (3+i*3) then
begin
x1:=BaseTable[(ord(Source[1+i*3]) shr 2)+1];
xt:=(ord(Source[1+i*3]) shl 4) and 48;
xt:=xt or (ord(Source[2+i*3]) shr 4);
x2:=BaseTable[xt+1];
xt:=(Ord(Source[2+i*3]) shl 2) and 60;
xt:=xt or (ord(Source[3+i*3]) shr 6);
x3:=BaseTable[xt+1];
xt:=(ord(Source[3+i*3]) and 63);
x4:=BaseTable[xt+1];
end
else if LenSrc>=(2+i*3) then
begin
x1:=BaseTable[(ord(Source[1+i*3]) shr 2)+1];
xt:=(ord(Source[1+i*3]) shl 4) and 48;
xt:=xt or (ord(Source[2+i*3]) shr 4);
x2:=BaseTable[xt+1];
xt:=(ord(Source[2+i*3]) shl 2) and 60;
x3:=BaseTable[xt+1];
x4:='=';
end else
begin
x1:=BaseTable[(ord(Source[1+i*3]) shr 2)+1];
xt:=(ord(Source[1+i*3]) shl 4) and 48;
x2:=BaseTable[xt+1];
x3:='=';
x4:='=';
end;
result:=result+x1+x2+x3+x4;
end;
end;
exports
EncodeBase64;
//解码函数
function DecodeBase64(Source:ShortString):ShortString; stdcall;
var
SrcLen,Times,i:integer;
x1,x2,x3,x4,xt:byte;
begin
result:='';
SrcLen:=Length(Source);
Times:=SrcLen div 4;
for i:=0 to Times-1 do
begin
x1:=FindInTable(Source[1+i*4]);
x2:=FindInTable(Source[2+i*4]);
x3:=FindInTable(Source[3+i*4]);
x4:=FindInTable(Source[4+i*4]);
x1:=x1 shl 2;
xt:=x2 shr 4;
x1:=x1 or xt;
x2:=x2 shl 4;
result:=result+chr(x1);
if x3= 64 then break;
xt:=x3 shr 2;
x2:=x2 or xt;
x3:=x3 shl 6;
result:=result+chr(x2);
if x4=64 then break;
x3:=x3 or x4;
result:=result+chr(x3);
end;
end;
exports
DecodeBase64;
{//编码函数
function TestDll(Source:ShortString ):ShortString ;stdcall;
var
Times,LenSrc,i:integer;
x1,x2,x3,x4:char;
xt:byte;
begin
result:='';

LenSrc:=length(Source);
if LenSrc mod 3 =0 then Times:=LenSrc div 3
else Times:=LenSrc div 3 + 1;
for i:=0 to times-1 do
begin
if LenSrc >= (3+i*3) then
begin
x1:=BaseTable[(ord(Source[1+i*3]) shr 2)+1];
xt:=(ord(Source[1+i*3]) shl 4) and 48;
xt:=xt or (ord(Source[2+i*3]) shr 4);
x2:=BaseTable[xt+1];
xt:=(Ord(Source[2+i*3]) shl 2) and 60;
xt:=xt or (ord(Source[3+i*3]) shr 6);
x3:=BaseTable[xt+1];
xt:=(ord(Source[3+i*3]) and 63);
x4:=BaseTable[xt+1];
end
else if LenSrc>=(2+i*3) then
begin
x1:=BaseTable[(ord(Source[1+i*3]) shr 2)+1];
xt:=(ord(Source[1+i*3]) shl 4) and 48;
xt:=xt or (ord(Source[2+i*3]) shr 4);
x2:=BaseTable[xt+1];
xt:=(ord(Source[2+i*3]) shl 2) and 60;
x3:=BaseTable[xt+1];
x4:='=';
end else
begin
x1:=BaseTable[(ord(Source[1+i*3]) shr 2)+1];
xt:=(ord(Source[1+i*3]) shl 4) and 48;
x2:=BaseTable[xt+1];
x3:='=';
x4:='=';
end;
result:=result+x1+x2+x3+x4;
end;
end;

///
exports
TestDll;
}
begin
end.

主程序调用（当然是静态的，动态的，我在修改）
unit Unit1;

interface

uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls;

type
TForm1 = class(TForm)
Edit1: TEdit;
Button1: TButton;
Edit2: TEdit;
Edit3: TEdit;
Button2: TButton;
Button3: TButton;
procedure Button1Click(Sender: TObject);
procedure Button2Click(Sender: TObject);
procedure Button3Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;

var
Form1: TForm1;

implementation

{$R *.dfm}
function DecodeBase64(Source:ShortString):ShortString; stdcall;external 'Project2.dll';
function EncodeBase64(Source:ShortString):ShortString;stdcall;
external 'Project2.dll';


procedure TForm1.Button1Click(Sender: TObject);
begin
//Edit1.Text:=IntToStr(TestDll(2));

end;

procedure TForm1.Button2Click(Sender: TObject);
begin
//edit2.text:=EncodeBase64(edit1.text);
edit2.text:=EncodeBase64(edit1.text);
end;

procedure TForm1.Button3Click(Sender: TObject);
begin
edit3.text:=DecodeBase64 (edit2.text);
end;

end.

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