今天在工作中需要解决这样一个问题：压缩和解压一个文件，其中所有的过程都是基于内存中进行的。因为这个原因，基本的压缩工作比如说ZIPLIB等都不能使用。后来从网上找到了这样一段代码。

procedure CompressIt(var CompressedStream: TMemoryStream; const CompressionLevel: TCompressionLevel); // 参数是传递的流和压缩方式 var SourceStream: TCompressionStream; DestStream: TMemoryStream; Count: int64; //注意，此处修改了,原来是int begin //获得流的原始尺寸 Count := CompressedStream.Size; DestStream := TMemoryStream.Create; SourceStream := TCompressionStream.Create(CompressionLevel, DestStream); try //SourceStream中保存着原始的流 CompressedStream.SaveToStream(SourceStream); //将原始流进行压缩， DestStream中保存着压缩后的流 SourceStream.Free; CompressedStream.Clear; //写入原始图像的尺寸 CompressedStream.WriteBuffer(Count, SizeOf(Count)); //写入经过压缩的流 CompressedStream.CopyFrom(DestStream, 0); finally DestStream.Free; end; end; procedure UnCompressit(const CompressedStream: TMemoryStream; var UnCompressedStream: TMemoryStream); //参数 压缩过的流，解压后的流 var SourceStream: TDecompressionStream; DestStream: TMemoryStream; Buffer: PChar; Count: int64; begin //从被压缩的图像流中读出原始的尺寸 CompressedStream.ReadBuffer(Count, SizeOf(Count)); //根据尺寸大小为将要读入的原始流分配内存块 GetMem(Buffer, Count); DestStream := TMemoryStream.Create; SourceStream := TDecompressionStream.Create(CompressedStream); try //将被压缩的流解压缩，然后存入 Buffer内存块中 SourceStream.ReadBuffer(Buffer^, Count); //将原始流保存至 DestStream流中 DestStream.WriteBuffer(Buffer^, Count); DestStream.Position := 0; //复位流指针 // DestStream.Position := length(VER_INFO); //从 DestStream流中载入图像流 UnCompressedStream.LoadFromStream(DestStream); finally FreeMem(Buffer); DestStream.Free; end; end;

后来因为需求的改变，也是基于内存但是需要一次压缩和解压多个文件。以上的方法就不适用了。在这个过程中我网上搜索到ZIPFORG可以解决这个问题。于是下载了ZIPFORGE

function CompressitMultiFileByZipforge(str_needtocompress_filenamelist: TStringList; str_zip_file_name: string):Boolean; var my_ms, my_dest: TMemoryStream; strZipFile, str_cur_file_name, str_file_name: string; my_ZipForge: TZipForge; i, i_file_count: Integer; is_ok :Boolean; begin strZipFile := str_zip_file_name; my_ZipForge := TZipForge.Create(nil); i_file_count := str_needtocompress_filenamelist.Count; my_ms := TMemoryStream.Create; my_dest := TMemoryStream.Create; is_ok := True; try begin //my_ZipForge.FileName := strZipFile; my_ZipForge.InMemory := True;//如果是基于内存流很重要 my_ZipForge.OpenArchive(my_dest, True); if i_file_count = 0 then begin is_ok := False; end else begin for i := 0 to i_file_count - 1 do begin str_file_name := str_needtocompress_filenamelist.Strings[i]; str_cur_file_name := gHidePathPrefix + str_file_name; my_ms := GetMemoryStreamByFileName(str_cur_file_name); if my_ms.Size <> 0 then begin my_ZipForge.AddFromStream(str_file_name, my_ms, True); end; my_ms.Clear; end; if my_dest.Size <> 0 then begin DM.LionSunMANET.DiskManage.SaveFile(str_zip_file_name, my_dest); is_ok := True; end else begin is_ok := False; end; end; my_ms.Clear; my_dest.Clear; my_ZipForge.CloseArchive; end finally begin my_ms.Free; my_dest.Free; end; end; end;

解压的部分代码如下：

function DeCompressSingleZipFileByZipforge(str_needtodecompress_filename:string;str_zip_file_name:string):Boolean; var my_ms, my_dest: TMemoryStream; strZipFile, str_dest_file_name, str_file_name: string; my_ZipForge: TZipForge; is_ok :Boolean; begin strZipFile := str_zip_file_name; my_ZipForge := TZipForge.Create(nil); my_ms := TMemoryStream.Create; my_dest := TMemoryStream.Create; is_ok := True; try begin // Zip文件的文件名 if DM.LionSunMANET.DiskManage.ReadFile(strZipFile,my_ms) = 1 then begin //my_ZipForge.FileName := strZipFile; my_ZipForge.InMemory := True;//关键 // 打开压缩文档 my_ZipForge.OpenArchive(my_ms,False);//关键 str_file_name := str_needtodecompress_filename; my_ZipForge.ExtractToStream(str_file_name,my_dest); str_dest_file_name := gHidePathPrefix + str_file_name; my_dest.Position := 0; DM.LionSunMANET.DiskManage.SaveFile(str_dest_file_name,my_dest); my_dest.Clear; // 关闭压缩文档 my_ms.Clear; my_ZipForge.CloseArchive; is_ok := True; end else begin my_dest.Clear; my_ms.Clear; is_ok := False; end; end; finally begin my_ms.Free; my_dest.Free; end; end; Result := is_ok; end;