实用的内存块操作类(vb源码)

最新推荐文章于 2024-11-02 11:08:30 发布

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最新推荐文章于 2024-11-02 11:08:30 发布

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文章标签： vb function string class

本文介绍了一种使用VB进行内存操作的方法，包括内存分配、读取、写入和释放等过程。通过调用kernel32.dll中的函数实现这些操作，如VirtualAlloc、VirtualFree等。

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导读：
　　(声明：魏滔序原创，转贴请注明出处。)
　　Option Explicit
　　Private Declare Function VirtualAlloc Lib "kernel32" (ByVal lpAddress As Long, ByVal dwSize As Long, ByVal flAllocationType As Long, ByVal flProtect As Long) As Long
　　Private Declare Function VirtualFree Lib "kernel32" (ByVal lpAddress As Long, ByVal dwSize As Long, ByVal dwFreeType As Long) As Long
　　Private Declare Function VirtualLock Lib "kernel32" (ByVal lpAddress As Long, ByVal dwSize As Long) As Long
　　Private Declare Function VirtualUnlock Lib "kernel32" (ByVal lpAddress As Long, ByVal dwSize As Long) As Long
　　Private Declare Function IsBadReadPtr Lib "kernel32" (ByVal lp As Long, ByVal ucb As Long) As Long
　　Private Declare Function IsBadWritePtr Lib "kernel32" (ByVal lp As Long, ByVal ucb As Long) As Long
　　Private Declare Function IsBadStringPtr Lib "kernel32" Alias "IsBadStringPtrA" (ByVal lpsz As Long, ByVal ucchMax As Long) As Long
　　Private Declare Function lstrcpy Lib "kernel32" Alias "lstrcpyA" (ByVal lpStringDest As String, ByVal lpStringSrc As Long) As Long
　　Private Declare Function lstrlen Lib "kernel32" Alias "lstrlenA" (ByVal lpString As Long) As Long
　　Private Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" (ByVal pDest As Long, ByVal pSrc As Long, ByVal ByteLen As Long)
　　Private Const MEM_DECOMMIT = &H4000
　　Private Const MEM_RELEASE = &H8000
　　Private Const MEM_COMMIT = &H1000
　　Private Const PAGE_EXECUTE_READWRITE = &H40
　　Private m_Handle As Long
　　Public Property Get Handle() As Long
　　Handle = m_Handle
　　End Property
　　'分配内存
　　Public Sub Allocate(ByVal lCount As Long)
　　Call Release
　　m_Handle = VirtualAlloc(ByVal 0&, lCount, MEM_COMMIT, PAGE_EXECUTE_READWRITE)
　　VirtualLock m_Handle, lCount
　　End Sub
　　'读取
　　Public Sub ReadFromPointer(ByVal hWritePointer As Long, ByVal lLength As Long)
　　If IsBadWritePtr(hWritePointer, lLength) = 0 And IsBadReadPtr(Handle, lLength) = 0 Then
　　CopyMemory hWritePointer, Handle, lLength
　　End If
　　End Sub
　　'写入
　　Public Sub WriteToPointer(ByVal hReadPointer As Long, ByVal lLength As Long)
　　If IsBadReadPtr(hReadPointer, lLength) = 0 And IsBadWritePtr(Handle, lLength) = 0 Then
　　CopyMemory Handle, hReadPointer, lLength
　　End If
　　End Sub
　　'释放内存
　　Public Sub Release()
　　Dim lLength As Long
　　If m_Handle <>0 Then
　　VirtualUnlock m_Handle, lLength
　　VirtualFree m_Handle, lLength, MEM_DECOMMIT
　　VirtualFree m_Handle, 0, MEM_RELEASE
　　m_Handle = 0
　　End If
　　End Sub
　　Private Sub Class_Terminate()
　　Call Release
　　End Sub
　　Trackback: http://tb.blog.youkuaiyun.com/TrackBack.aspx?PostId=1342718

本文转自
http://blog.youkuaiyun.com/modest/archive/2006/10/20/1342718.aspx