那位大侠知道数据压缩的问题(0分)

我的系统是做对文件的处理，有数据库的，现在要求在入库前对文件进行压缩，
下载、浏览文件的时候再对文件进行解压。。。
知道这方面技术的大侠re！！！！！

你可以仿照下面的内容作出来，从网上搜的程序改编而来
uses
zlib;
procedure CompressStream(var CompressedStream: TMemoryStream;
const CompressionLevel: TCompressionLevel);
//压缩方式:clnone,clfastest,cldefault,clmax
procedure giveScreen(const CompressedStream: TMemoryStream;
var Bmp: TBitmap);
procedure CompressStream(var CompressedStream: TMemoryStream;
const CompressionLevel: TCompressionLevel);
var
SourceStream: TCompressionStream;
DestStream: TMemoryStream;
Count: Integer;
infono:integer;
begin
//获得图像流的原始尺寸
infono:=1;
Count := CompressedStream.Size;
DestStream := TMemoryStream.Create;
SourceStream:=TCompressionStream.Create(CompressionLevel, DestStream);
Try
//SourceStream中保存着原始的图像流
CompressedStream.SaveToStream(SourceStream);
//将原始图像流进行压缩， DestStream中保存着压缩后的图像流
SourceStream.Free;
CompressedStream.Clear;
//写入原始图像的尺寸
CompressedStream.WriteBuffer(Infono,SizeOf(Infono));
CompressedStream.WriteBuffer(Count, SizeOf(Count));
//写入经过压缩的图像流
CompressedStream.CopyFrom(DestStream,0);
finally
DestStream.Free;
end;
end;

procedure giveScreen(const CompressedStream: TMemoryStream;
var Bmp: TBitmap);
var
SourceStream: TDecompressionStream;
DestStream: TMemoryStream;
Buffer: PChar;
Count: Integer;
begin
//从被压缩的图像流中读出原始图像的尺寸
//CompressedStream.position:=0;
CompressedStream.ReadBuffer(Count,SizeOf(Count));
//根据图像尺寸大小为将要读入的原始图像流分配内存块
GetMem(Buffer, Count);
DestStream := TMemoryStream.Create;
SourceStream := TDecompressionStream.Create(CompressedStream);
Try
//将被压缩的图像流解压缩，然后存入 Buffer内存块中
SourceStream.ReadBuffer(Buffer^, Count);
//将原始图像流保存至 DestStream流中
DestStream.WriteBuffer(Buffer^, Count);
DestStream.Position := 0;//复位流指针
//从 DestStream流中载入原始图像流
Bmp.LoadFromStream(DestStream);
finally
FreeMem(Buffer);
DestStream.Free;
SourceStream.Free;
end;
end;