虚拟内存空间代码,C代码库,德仔网

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【C】虚拟内存空间
作者:眼看前方_脚踏实地 / 发布于2013/10/24/ 749

	/******************************************************************************
	Module: VMAlloc.cpp
	Notices: Copyright (c) 2008 Jeffrey Richter & Christophe Nasarre
	******************************************************************************/

	
	#include "..\CommonFiles\CmnHdr.h" /* See Appendix A. */
	#include <WindowsX.h>
	#include <tchar.h>
	#include "Resource.h"
	#include <StrSafe.h>


	///////////////////////////////////////////////////////////////////////////////

	
	// The number of bytes in a page on this host machine. 本地机器的分配页的字节数
	UINT g_uPageSize = 0;

	UINT g_uMaxPages = 0;//最大页面数
	UINT g_uDrawMaxWidth = 0;//需要画的最大宽度
	UINT g_cellWidth = 0; //单元格宽度

	// A dummy data structure used for the array. 数组使用的虚拟数据结构体
	typedef struct {
	 BOOL bInUse;
	 BYTE bOtherData[2048 - sizeof(BOOL)];
	} SOMEDATA, *PSOMEDATA;


	// The number of structures in the array 数组的大小
	#define MAX_SOMEDATA (50)

	// Pointer to an array of data structures 指针指向结构体数组
	PSOMEDATA g_pSomeData = NULL;

	// The rectangular area in the window occupied by the memory map 内存图占窗口的矩形区域
	RECT g_rcMemMap;

	
	///////////////////////////////////////////////////////////////////////////////


	BOOL Dlg_OnInitDialog(HWND hWnd, HWND hWndFocus, LPARAM lParam) {
	
	 chSETDLGICONS(hWnd, IDI_VMALLOC);

	 // Initialize the dialog box by disabling all the nonsetup controls.
	 EnableWindow(GetDlgItem(hWnd, IDC_INDEXTEXT), FALSE);
	 EnableWindow(GetDlgItem(hWnd, IDC_INDEX), FALSE);
	 EnableWindow(GetDlgItem(hWnd, IDC_USE), FALSE);
	 EnableWindow(GetDlgItem(hWnd, IDC_CLEAR), FALSE);
	 EnableWindow(GetDlgItem(hWnd, IDC_GARBAGECOLLECT), FALSE);

	 // Get the coordinates of the memory map display. 获得屏幕坐标
	 GetWindowRect(GetDlgItem(hWnd, IDC_MEMMAP), &g_rcMemMap);

	 // 把屏幕坐标转到到hWnd坐标系去 即在父窗口的位置
	 MapWindowPoints(NULL, hWnd, (LPPOINT) &g_rcMemMap, 2);

	 // Destroy the window that identifies the location of the memory map
	 DestroyWindow(GetDlgItem(hWnd, IDC_MEMMAP));
	
	 // Put the page size in the dialog box just for the user's information.
	 TCHAR szBuf[10];
	 StringCchPrintf(szBuf, _countof(szBuf), TEXT("%d KB"), g_uPageSize / 1024);
	 SetDlgItemText(hWnd, IDC_PAGESIZE, szBuf);

	 // Initialize the edit control.
	 SetDlgItemInt(hWnd, IDC_INDEX, 0, FALSE);
	
	 g_uMaxPages = MAX_SOMEDATA * sizeof(SOMEDATA) / g_uPageSize;

	 g_uDrawMaxWidth = (g_rcMemMap.right - g_rcMemMap.left) / g_uMaxPages * g_uMaxPages;

	 g_cellWidth = g_uDrawMaxWidth / g_uMaxPages;

	 return(TRUE);
	}

	
	///////////////////////////////////////////////////////////////////////////////


	void Dlg_OnDestroy(HWND hWnd) {

	 if (g_pSomeData != NULL)
	 VirtualFree(g_pSomeData, 0, MEM_RELEASE);
	}


	///////////////////////////////////////////////////////////////////////////////

	VOID MyGarbageCollect(PSOMEDATA psomeData, DWORD dwnum, DWORD dwStructSize)
	{
	//一共有多少页
	UINT uMaxPages = g_uMaxPages;
	for (UINT uPage = 0; uPage < uMaxPages; ++uPage)
	{
	 BOOL bAnyAllocsInThisPage = FALSE;
	 BOOL bCommit = FALSE;

	 UINT uIndex = uPage * g_uPageSize / dwStructSize;
	 UINT uIndexLast = uIndex + g_uPageSize / dwStructSize;

	 for (; uIndex < uIndexLast; ++uIndex)
	 {
	 MEMORY_BASIC_INFORMATION mbi;

	 VirtualQuery(&g_pSomeData[uIndex],&mbi,sizeof(mbi));

	 bCommit = mbi.State == MEM_COMMIT;

	 if (bCommit && psomeData[uIndex].bInUse){
	 bAnyAllocsInThisPage = TRUE;
	 }
	 }
	 if (bCommit && !bAnyAllocsInThisPage)
	 {
	 VirtualFree(&psomeData[uIndexLast-1], dwStructSize, MEM_DECOMMIT);
	 }
	}
	}

	VOID GarbageCollect(PVOID pvBase, DWORD dwNum, DWORD dwStructSize) {

	 UINT uMaxPages = dwNum * dwStructSize / g_uPageSize;
	 for (UINT uPage = 0; uPage < uMaxPages; uPage++) {
	 BOOL bAnyAllocsInThisPage = FALSE;
	 UINT uIndex = uPage * g_uPageSize / dwStructSize;
	 UINT uIndexLast = uIndex + g_uPageSize / dwStructSize;

	 for (; uIndex < uIndexLast; uIndex++) {
	 MEMORY_BASIC_INFORMATION mbi;
	 VirtualQuery(&g_pSomeData[uIndex], &mbi, sizeof(mbi));
	 bAnyAllocsInThisPage = ((mbi.State == MEM_COMMIT) &&
	 * (PBOOL) ((PBYTE) pvBase + dwStructSize * uIndex));

	 // Stop checking this page, we know we can't decommit it.
	 if (bAnyAllocsInThisPage) break;
	 }

	 if (!bAnyAllocsInThisPage) {
	 // No allocated structures in this page; decommit it.
	 VirtualFree(&g_pSomeData[uIndexLast - 1], dwStructSize, MEM_DECOMMIT);
	 }
	 }
	}


	///////////////////////////////////////////////////////////////////////////////

	
	void Dlg_OnCommand(HWND hWnd, int id, HWND hWndCtl, UINT codeNotify) {

	 UINT uIndex = 0;

	 switch (id) {
	 case IDCANCEL:
	 EndDialog(hWnd, id);
	 break;

	 case IDC_RESERVE:
	 // Reserve enough address space to hold the array of structures. 分配虚拟区域 50个结构体大小
	 g_pSomeData = (PSOMEDATA) VirtualAlloc(NULL,
	 MAX_SOMEDATA * sizeof(SOMEDATA), MEM_RESERVE, PAGE_READWRITE);

	 // Disable the Reserve button and enable all the other controls.
	 EnableWindow(GetDlgItem(hWnd, IDC_RESERVE), FALSE);
	 EnableWindow(GetDlgItem(hWnd, IDC_INDEXTEXT), TRUE);
	 EnableWindow(GetDlgItem(hWnd, IDC_INDEX), TRUE);
	 EnableWindow(GetDlgItem(hWnd, IDC_USE), TRUE);
	 EnableWindow(GetDlgItem(hWnd, IDC_GARBAGECOLLECT), TRUE);

	 // Force the index edit control to have the focus.
	 SetFocus(GetDlgItem(hWnd, IDC_INDEX));
	
	 // Force the memory map to update
	 InvalidateRect(hWnd, &g_rcMemMap, FALSE);
	 break;

	 case IDC_INDEX:
	 if (codeNotify != EN_CHANGE)
	 break;

	 uIndex = GetDlgItemInt(hWnd, id, NULL, FALSE);
	 if ((g_pSomeData != NULL) && chINRANGE(0, uIndex, MAX_SOMEDATA - 1)) {
	 MEMORY_BASIC_INFORMATION mbi;
	 VirtualQuery(&g_pSomeData[uIndex], &mbi, sizeof(mbi));
	 BOOL bOk = (mbi.State == MEM_COMMIT);
	 if (bOk)
	 bOk = g_pSomeData[uIndex].bInUse;

	 EnableWindow(GetDlgItem(hWnd, IDC_USE), !bOk);
	 EnableWindow(GetDlgItem(hWnd, IDC_CLEAR), bOk);

	 } else {
	 EnableWindow(GetDlgItem(hWnd, IDC_USE), FALSE);
	 EnableWindow(GetDlgItem(hWnd, IDC_CLEAR), FALSE);
	 }
	 break;
	

	 case IDC_USE:
	 uIndex = GetDlgItemInt(hWnd, IDC_INDEX, NULL, FALSE);
	 // NOTE: New pages are always zeroed by the system
	 VirtualAlloc(&g_pSomeData[uIndex], sizeof(SOMEDATA),
	 MEM_COMMIT, PAGE_READWRITE); //分配页面是4KB 刚好是2个结构体大小

	 g_pSomeData[uIndex].bInUse = TRUE;

	 EnableWindow(GetDlgItem(hWnd, IDC_USE), FALSE);
	 EnableWindow(GetDlgItem(hWnd, IDC_CLEAR), TRUE);

	 // Force the Clear button control to have the focus.
	 SetFocus(GetDlgItem(hWnd, IDC_CLEAR));
	
	 // Force the memory map to update
	 InvalidateRect(hWnd, &g_rcMemMap, FALSE);
	 break;

	 case IDC_CLEAR:
	 uIndex = GetDlgItemInt(hWnd, IDC_INDEX, NULL, FALSE);
	 g_pSomeData[uIndex].bInUse = FALSE;
	 EnableWindow(GetDlgItem(hWnd, IDC_USE), TRUE);
	 EnableWindow(GetDlgItem(hWnd, IDC_CLEAR), FALSE);

	 // Force the Use button control to have the focus.
	 SetFocus(GetDlgItem(hWnd, IDC_USE));
	 break;

	 case IDC_GARBAGECOLLECT:
	 MyGarbageCollect(g_pSomeData, MAX_SOMEDATA, sizeof(SOMEDATA));

	 // Force the memory map to update
	 InvalidateRect(hWnd, &g_rcMemMap, FALSE);
	 break;
	 }
	}

	
	///////////////////////////////////////////////////////////////////////////////


	void Dlg_OnPaint(HWND hWnd) { // Update the memory map

	 PAINTSTRUCT ps;
	 BeginPaint(hWnd, &ps);

	 UINT uMaxPages = g_uMaxPages;
	 UINT uMemMapWidth = g_uDrawMaxWidth;
	
	 if (g_pSomeData == NULL) {

	 // The memory has yet to be reserved.

	 Rectangle(ps.hdc, g_rcMemMap.left, g_rcMemMap.top,
	 g_rcMemMap.left + uMemMapWidth, g_rcMemMap.bottom);

	 } else {

	 // Walk the virtual address space, painting the memory map
	 for (UINT uPage = 0; uPage < uMaxPages; uPage++) {

	 UINT uIndex = uPage * g_uPageSize / sizeof(SOMEDATA);
	 UINT uIndexLast = uIndex + g_uPageSize / sizeof(SOMEDATA);
	 for (; uIndex < uIndexLast; uIndex++) {

	 MEMORY_BASIC_INFORMATION mbi;
	 VirtualQuery(&g_pSomeData[uIndex], &mbi, sizeof(mbi));

	 int nBrush = 0;
	 switch (mbi.State) {
	 case MEM_FREE: nBrush = WHITE_BRUSH; break;
	 case MEM_RESERVE: nBrush = GRAY_BRUSH; break;
	 case MEM_COMMIT: nBrush = BLACK_BRUSH; break;
	 }

	 SelectObject(ps.hdc, GetStockObject(nBrush));
	 Rectangle(ps.hdc,
	 g_rcMemMap.left + g_cellWidth * uPage,
	 g_rcMemMap.top,
	 g_rcMemMap.left + g_cellWidth * (uPage + 1),
	 g_rcMemMap.bottom);
	 }
	 }
	 }

	 EndPaint(hWnd, &ps);
	}


	///////////////////////////////////////////////////////////////////////////////

	
	INT_PTR WINAPI Dlg_Proc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam) {
	
	 switch (uMsg) {
	 chHANDLE_DLGMSG(hWnd, WM_INITDIALOG, Dlg_OnInitDialog);
	 chHANDLE_DLGMSG(hWnd, WM_COMMAND, Dlg_OnCommand);
	 chHANDLE_DLGMSG(hWnd, WM_PAINT, Dlg_OnPaint);
	 chHANDLE_DLGMSG(hWnd, WM_DESTROY, Dlg_OnDestroy);
	 }
	 return(FALSE);
	}


	///////////////////////////////////////////////////////////////////////////////

	
	int WINAPI _tWinMain(HINSTANCE hInstExe, HINSTANCE, PTSTR, int) {

	 // Get the page size used on this CPU.
	 SYSTEM_INFO si;
	 GetSystemInfo(&si);
	 g_uPageSize = si.dwPageSize; //获得页面大小

	 DialogBox(hInstExe, MAKEINTRESOURCE(IDD_VMALLOC), NULL, Dlg_Proc);
	 return(0);
	}


	//////////////////////////////// End of File //////////////////////////////////
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