关于函数参数指针的使用

Question

var
FS:TfileStream;
tempstream:tmemorystream;
buffer:array of byte;
begin FS:=tfilestream.Create('123.tmp',fmOpenReadWrite or  fmShareDenyNone); tempstream:=tmemorystream.Create;
 
fs.Position:=0;
 
tempstream.CopyFrom(fs,0);//把123.tmp全部拷贝到内存流
 
setlength(buffer,2048);
 
ZDecompress(tempstream,1024,pointer(buffer),2048);// 1024 2048指大小，假设123.tmp压缩前是2048 压缩后是1024，调用 ZDecompress解压缩
 
tempstream.write(buffer,2048) ;//解压缩后的数据流存入tempstream。。
这里是zlib的ZDecompress原型
procedure ZDecompress(const inBuffer: Pointer; inSize: Integer;
 out outBuffer: Pointer; out outSize: Integer; outEstimate: Integer = 0);我想利用zlib的ZDecompress把123.tmp进行解压然后保存解压后的文件，关键是这个ZDecompress不知道怎么用，我上面的代码肯定是错的，请问该怎么修改啊，最近被指针搞得要死，谢谢大家

Answer 1

{-------------------------------------------------------------------------------
 单元名: uZlibClass.pas
 功能  : 简单压缩 -- Zlib
 作者  : Duo
 日期  ：2010-04-28 22:04:09
 说明  ：压缩解压 流，文件
-------------------------------------------------------------------------------}
unit uZlibClass;interfaceuses Windows,SysUtils,Classes,ZLib,Forms;type
  TZlibOnProgressEvent = procedure (AFileSize,AFilePos:Int64) of object;
  TZlibClass=class
  private
    FFilePos: Int64;
    FFileSize: Int64;
    FOnProgress: TZlibOnProgressEvent;
    procedure CsProgress(Sender:TObject); // 压缩
    procedure DsProgress(Sender:TObject); // 解压
  public
    procedure CompressionStream(ASourceStream,ATargetStream:TMemoryStream);
    procedure DecompressionStream(ASourceStream,ATargetStream:TMemoryStream);
    procedure CompressionFile(const ASourceFile,ATargetFile:TFileName);
    procedure DecompressionFile(const ASourceFile,ATargetFile:TFileName);
    property FileSize:Int64 read FFileSize;
    property FilePos:Int64 read FFilePos;
    property OnProgress:TZlibOnProgressEvent read FOnProgress write FOnProgress;
  end;implementation{ TZlibClass }procedure TZlibClass.CompressionFile(const ASourceFile, ATargetFile: TFileName);
var fs,ms:TMemoryStream;
begin
  fs:=TMemoryStream.Create;
  ms:=TMemoryStream.Create;
  try
    fs.LoadFromFile(ASourceFile);
    CompressionStream(fs,ms);
    ms.SaveToFile(ATargetFile);
  finally
    FreeAndNil(ms);
    FreeAndNil(fs);
  end;
end;procedure TZlibClass.CompressionStream(ASourceStream,ATargetStream:TMemoryStream);
var cs:TCompressionStream;
begin
  FFileSize:=ASourceStream.Size;
  ATargetStream.Write(FFileSize,SizeOf(FFileSize));
  cs:=TCompressionStream.Create(clMax,ATargetStream);
  try
    cs.OnProgress := CsProgress;
    ASourceStream.SaveToStream(cs);
  finally
    FreeAndNil(cs);
  end;
end;procedure TZlibClass.CsProgress(Sender: TObject);
begin
  FFilePos:=TCompressionStream(Sender).Position;
  if Assigned(FOnProgress) then FOnProgress(FFileSize,FFilePos);
  Application.ProcessMessages;
end;procedure TZlibClass.DecompressionFile(const ASourceFile,
  ATargetFile: TFileName);
var fs,ms:TMemoryStream;
begin
  fs:=TMemoryStream.Create;
  ms:=TMemoryStream.Create;
  try
    fs.LoadFromFile(ASourceFile);
    DecompressionStream(fs,ms);
    ms.SaveToFile(ATargetFile);
  finally
    FreeAndNil(ms);
    FreeAndNil(fs);
  end;
end;procedure TZlibClass.DecompressionStream(ASourceStream,ATargetStream:TMemoryStream);
var ds:TDecompressionStream;
begin
  ASourceStream.Position:=0;
  ASourceStream.ReadBuffer(FFileSize,SizeOf(FFileSize));
  ATargetStream.SetSize(FFileSize);
  ds:=TDecompressionStream.Create(ASourceStream);
  try
    ds.OnProgress:=DsProgress;
    ds.Read(ATargetStream.Memory^,FFileSize);
  finally
    FreeAndNil(ds);
  end;
end;procedure TZlibClass.DsProgress(Sender: TObject);
begin
  FFilePos:=TDecompressionStream(Sender).Position;
  if Assigned(FOnProgress) then FOnProgress(FFileSize,FFilePos);
  Application.ProcessMessages;
end;end.

Answer 2

ZDecompress(tempstream.memory,1024,pointer(buffer),2048);

Answer 3

还有
tempstream.write(buffer[0],2048);

Answer 4

请问我想调用动态库，C++ 的 函数里有个参数是指针形的。我在delphi里怎么用啊？