内存管理[6]

本例效果图:

---

unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    Button1: TButton;
    Button2: TButton;
    Memo1: TMemo;
    Memo2: TMemo;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

//测试堆的内存占用情况
procedure TForm1.Button1Click(Sender: TObject);
var
  MyHeap: THandle;
  mem: TMemoryStatus;
  m1,m2,m3: DWORD;
begin
  {获取当前内存可用状态}
  GlobalMemoryStatus(mem);
  m1 := mem.dwAvailPhys;     {可用物理内存}
  m2 := mem.dwAvailPageFile; {可用虚拟内存}
  m3 := mem.dwAvailVirtual;  {可用虚拟地址}

  {建立私有堆}
  MyHeap := HeapCreate(HEAP_NO_SERIALIZE, 1024*1204, 0); {建立 1 M 大小的堆}

  {再获取当前内存可用状态}
  GlobalMemoryStatus(mem);
  m1 := m1 - mem.dwAvailPhys;
  m2 := m2 - mem.dwAvailPageFile;
  m3 := m3 - mem.dwAvailVirtual;

  {显示堆占用内存的情况}
  Memo1.Clear;
  Memo1.Lines.Add(Format('占用物理内存: %d K', [m1 div 1024]));
  Memo1.Lines.Add(Format('占用虚拟内存: %d K', [m2 div 1024]));
  Memo1.Lines.Add(Format('占用虚拟地址: %d K', [m3 div 1024]));

  {释放堆}
  HeapDestroy(MyHeap);
end;

//同上个过程, 外加测试建立堆时页对齐的情况
procedure TForm1.Button2Click(Sender: TObject);
var
  MyHeap: THandle;
  mem: TMemoryStatus;
  m1,m2,m3: DWORD;
begin
  GlobalMemoryStatus(mem);
  m1 := mem.dwAvailPhys;     
  m2 := mem.dwAvailPageFile; 
  m3 := mem.dwAvailVirtual;

  {建立 1M + 1字节 大小的堆, 但实际大小会按页对齐, 结果应该是: 1M + 4K}
  MyHeap := HeapCreate(HEAP_NO_SERIALIZE, 1024*1204 + 1, 0);

  GlobalMemoryStatus(mem);
  m1 := m1 - mem.dwAvailPhys;
  m2 := m2 - mem.dwAvailPageFile;
  m3 := m3 - mem.dwAvailVirtual;

  Memo2.Clear;
  Memo2.Lines.Add(Format('占用物理内存: %d K', [m1 div 1024]));
  Memo2.Lines.Add(Format('占用虚拟内存: %d K', [m2 div 1024]));
  Memo2.Lines.Add(Format('占用虚拟地址: %d K', [m3 div 1024]));

  HeapDestroy(MyHeap);
end;

end.