delphi 文件/流的加密解密方法

(*
* 单元说明: 文件/流的加密解密方法(For Delphi 6-7)
*
*
* 使用说明: 此文件的代码可以直接编译使用,
* 您可以根据需要编写自己的加密/解密代码.
*
* 声 明: 以下代码属作者原创, 请转载时保留本信息. 
*
*)
unit uCompress;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, ComCtrls, Dialogs;
// 压缩/解压文件
procedure CompressFile(Source, Target: String,',','); stdcall;
procedure DecompressFile(Source, Target: String,',','); stdcall;
// 压缩/解压文件到流
procedure CompressToStream(FileName: String; Stream: TStream,',','); stdcall;
procedure DecompressToStream(FileName: String; Stream: TStream,',','); stdcall;
// 压缩/解压流
procedure CompressStream(InStream, OutStream: TStream,',','); stdcall;
procedure DecompressStream(InStream, OutStream: TStream,',','); stdcall;
implementation
uses
ZLib;
const
COMPRESS_ERROR = '压缩文件时出现内部错误:';
DECOMPRESS_ERROR = '解压文件时出现内部错误:';
COMPRESS_STRM_ERROR = '压缩流时出现内部错误:';
DECOMPRESS_STRM_ERROR = '解压流时出现内部错误:'; 
BufSize = $4096;
// 压缩文件
procedure CompressFile(Source, Target: String,',',');
var
i: Integer;
Buf: array[0..BufSize] of byte;
ComStream: TCompressionStream;
InStream, OutStream: TFileStream;
begin
if not FileExists(Source) then
Exit;
InStream := Nil;
OutStream := nil;
ComStream := nil;
try
// 生成流
InStream := TFileStream.Create(Source, fmOpenRead OR fmShareDenyNone,',',');
OutStream := TFileStream.Create(Target, fmCreate OR fmShareDenyWrite,',',');
ComStream := TCompressionStream.Create(clMax, OutStream,',',');
// 压缩流
for i := 1 to (InStream.Size div BufSize) do begin
InStream.ReadBuffer(Buf, BufSize,',',');
ComStream.Write(Buf, BufSize,',',');
end;
i := InStream.Size mod BufSize;
if (i > 0) then begin
InStream.ReadBuffer(Buf, i,',',');
ComStream.Write(Buf, i,',',');
End;
InStream.Free;
InStream := nil;
// 注先后
ComStream.Free;
ComStream := nil;
// 在此写加密流代码(要先释放 ComStream)
// EncryptStream(OutStream,',',');
OutStream.Free;
OutStream := nil;
except
on E: Exception do begin
if (InStream <> nil) then
InStream.Free;
if (OutStream <> nil) then
OutStream.Free;
if (ComStream <> nil) then
ComStream.Free;
MessageDlg(COMPRESS_ERROR + #10 + E.Message, mtError, [mbOk], 0,',',');
end;
end;
end;
// 解压文件
procedure DecompressFile(Source, Target: String,',',');
var
i: Integer;
Buf: array[0..BufSize] of Byte;
DecomStream: TDecompressionStream;
MemStream: TMemoryStream;
OutStream: TFileStream;
begin
if not FileExists(Source) then
Exit;
MemStream := Nil;
OutStream := nil;
DecomStream := nil;
try
// 生成流
// 先读文件到 MemStream 中解密(Source 只读).
// DecomStream 的开始位置 = MemStream.Position
MemStream := TMemoryStream.Create;
MemStream.LoadFromFile(Source,',',');
// 在此写解密流代码 
// DecryptStream(MemStream,',',');
OutStream := TFileStream.Create(Target, fmCreate or fmShareDenyWrite,',',');
DecomStream := TDeCompressionStream.Create(MemStream,',',');
{ InStream := TFileStream.Create(Source, fmOpenRead or fmShareDenyNone,',',');
OutStream := TFileStream.Create(Target, fmCreate or fmShareDenyWrite,',',');
DecomStream := TDeCompressionStream.Create(InStream,',','); }
// 解压流
repeat
i := DecomStream.Read(Buf, BufSize,',',');
OutStream.WriteBuffer(Buf, i,',',');
until (i = 0,',',');
// 注意先后
OutStream.Free;
OutStream := nil;
DecomStream.Free;
DecomStream := nil;
MemStream.Free;
MemStream := Nil;
except
on E: Exception do begin
if (MemStream <> nil) then
MemStream.Free;
if (OutStream <> nil) then
OutStream.Free;
if (DecomStream <> nil) then
DecomStream.Free;
MessageDlg(DECOMPRESS_ERROR + #10 + E.Message, mtError, [mbOk], 0,',',');
end;
end;
end;
// 压缩文件到流
procedure CompressToStream(FileName: String; Stream: TStream,',',');
var
i: Integer;
Buf: array[0..BufSize] of byte;
ComStream: TCompressionStream;
InStream: TFileStream; 
begin
if not FileExists(FileName) then
Exit;
InStream := Nil;
ComStream := nil;
try
// 生成流
InStream := TFileStream.Create(FileName, fmOpenRead OR fmShareDenyNone,',',');
ComStream := TCompressionStream.Create(clMax, Stream,',',');
// 压缩流
for i := 1 to (InStream.Size div BufSize) do begin
InStream.ReadBuffer(Buf, BufSize,',',');
ComStream.Write(Buf, BufSize,',',');
end;
i := InStream.Size mod BufSize;
if (i > 0) then begin
InStream.ReadBuffer(Buf, i,',',');
ComStream.Write(Buf, i,',',');
End;
InStream.Free;
InStream := nil;
ComStream.Free;
ComStream := nil;
// 在此写加密流代码(要先释放 ComStream), Postion = 0
// EncryptStream(Stream,',',');
except
on E: Exception do begin
if (InStream <> nil) then
InStream.Free;
if (ComStream <> nil) then
ComStream.Free;
MessageDlg(COMPRESS_ERROR + #10 + E.Message, mtError, [mbOk], 0,',',');
end;
end;
end;
// 解压文件到流
procedure DecompressToStream(FileName: String; Stream: TStream,',',');
var
i: Integer;
Buf: array[0..BufSize] of Byte;
DecomStream: TDecompressionStream;
MemStream: TMemoryStream;
begin
if not FileExists(FileName) then
Exit;
MemStream := Nil;
DecomStream := nil;
try
// 生成流
// 先读文件到 MemStream 中解密(FileName 只读).
// DecomStream 的开始位置 = MemStream.Position
MemStream := TMemoryStream.Create;
MemStream.LoadFromFile(FileName,',',');
// 在此写解密流代码
// DecryptStream(MemStream,',',');
DecomStream := TDeCompressionStream.Create(MemStream,',',');
// 解压流, Postion = 0
repeat
i := DecomStream.Read(Buf, BufSize,',',');
Stream.WriteBuffer(Buf, i,',',');
until (i = 0,',',');
Stream.Position := 0;
DecomStream.Free;
DecomStream := nil;
MemStream.Free;
MemStream := Nil;
except
on E: Exception do begin
if (MemStream <> nil) then
MemStream.Free;
if (DecomStream <> nil) then
DecomStream.Free;
MessageDlg(DECOMPRESS_ERROR + #10 + E.Message, mtError, [mbOk], 0,',',');
end;
end;
end;
// 压缩流
procedure CompressStream(InStream, OutStream: TStream,',',');
var
i: Integer;
Buf: array[0..BufSize] of byte;
ComStream: TCompressionStream;
begin
ComStream := Nil;
try
InStream.Position := 0;
ComStream := TCompressionStream.Create(clMax, OutStream,',',');
for i := 1 to (InStream.Size div BufSize) do begin
InStream.ReadBuffer(Buf, BufSize,',',');
ComStream.Write(Buf, BufSize,',',');
end;
i := InStream.Size mod BufSize;
if (i > 0) then begin
InStream.ReadBuffer(Buf, i,',',');
ComStream.Write(Buf, i,',',');
End;
ComStream.Free;
ComStream := nil;
// 在此写加密流代码
// EncryptStream(OutStream,',',');
except
on E: Exception do begin
if (ComStream <> nil) then
ComStream.Free;
MessageDlg(COMPRESS_STRM_ERROR + #10 + E.Message, mtError, [mbOk], 0,',',');
end;
end;
end;
// 解压流
procedure DecompressStream(InStream, OutStream: TStream,',',');
var
i: Integer;
Buf: array[0..BufSize] of Byte;
DecomStream: TDecompressionStream;
begin
DecomStream := nil;
try
// 在此写解密流代码
// DecryptStream(InStream,',',');
DecomStream := TDeCompressionStream.Create(InStream,',',');
repeat
i := DecomStream.Read(Buf, BufSize,',',');
OutStream.WriteBuffer(Buf, i,',',');
until (i = 0,',',');
OutStream.Position := 0;
DecomStream.Free;
DecomStream := nil;
except
on E: Exception do begin
if (DecomStream <> nil) then
DecomStream.Free;
MessageDlg(DECOMPRESS_STRM_ERROR + #10 + E.Message, mtError, [mbOk], 0,',',');
end;
end;
end;
end.