www.pudn.com > 020630_download.zip > cMemory.cls

VERSION 1.0 CLASS 
BEGIN 
  MultiUse = -1  'True 
  Persistable = 0  'NotPersistable 
  DataBindingBehavior = 0  'vbNone 
  DataSourceBehavior  = 0  'vbNone 
  MTSTransactionMode  = 0  'NotAnMTSObject 
END 
Attribute VB_Name = "cMemory" 
Attribute VB_GlobalNameSpace = False 
Attribute VB_Creatable = True 
Attribute VB_PredeclaredId = False 
Attribute VB_Exposed = False 
Option Explicit 
' ========================================================================== 
' Class:    cMemory 
' Filename: cMemory.cls 
' Author:   Steve McMahon 
' Date:     24 May 1998 
' 
' A class for manipulating API memory blocks. 
' ========================================================================== 
 
Private Declare Function GlobalAlloc Lib "kernel32" (ByVal wFlags As Long, ByVal dwBytes As Long) As Long 
Private Declare Function GlobalCompact Lib "kernel32" (ByVal dwMinFree As Long) As Long 
Private Declare Function GlobalFree Lib "kernel32" (ByVal hMem As Long) As Long 
Private Declare Function GlobalLock Lib "kernel32" (ByVal hMem As Long) As Long 
Private Declare Function GlobalReAlloc Lib "kernel32" (ByVal hMem As Long, ByVal dwBytes As Long, ByVal wFlags As Long) As Long 
Private Declare Function GlobalSize Lib "kernel32" (ByVal hMem As Long) As Long 
Private Declare Function GlobalUnlock Lib "kernel32" (ByVal hMem As Long) As Long 
Private Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" ( _ 
    lpvDest As Any, lpvSource As Any, ByVal cbCopy As Long) 
 
Public Enum EMemoryFlags 
    GMEM_DDESHARE = &H2000 
    GMEM_DISCARDABLE = &H100 
    GMEM_DISCARDED = &H4000 
    GMEM_INVALID_HANDLE = &H8000 
    GMEM_FIXED = &H0 
    GMEM_LOCKCOUNT = &HFF 
    GMEM_MODIFY = &H80 
    GMEM_MOVEABLE = &H2 
    GMEM_NODISCARD = &H20 
    GMEM_NOCOMPACT = &H10 
    GMEM_NOT_BANKED = &H1000 
    GMEM_LOWER = GMEM_NOT_BANKED 
    GMEM_NOTIFY = &H4000 
    GMEM_SHARE = &H2000 
    GMEM_VALID_FLAGS = &H7F72 
    GMEM_ZEROINIT = &H40 
    GPTR = (GMEM_FIXED Or GMEM_ZEROINIT) 
End Enum 
 
Private m_hMem As Long 
Private m_lPtr As Long 
 
Public Property Get Handle() As Long 
    Handle = m_hMem 
End Property 
Public Property Let Handle(ByVal hMem As Long) 
    If (m_hMem <> 0) Then 
        FreeMemory 
    End If 
    m_hMem = hMem 
End Property 
Public Property Get Pointer() As Long 
    If (m_hMem <> 0) Then 
        If (m_lPtr = 0) Then 
            LockMemory 
        End If 
        Pointer = m_lPtr 
    End If 
End Property 
Public Property Get Size() As Long 
    If (m_hMem <> 0) Then 
        Size = GlobalSize(m_hMem) 
    End If 
End Property 
Public Function AllocateMemory( _ 
        ByVal lSize As Long, _ 
        Optional ByVal dwFlags As Long = GPTR _ 
    ) As Boolean 
    FreeMemory 
    m_hMem = GlobalAlloc(dwFlags, lSize) 
    If (m_hMem <> 0) Then 
        ' Success 
        AllocateMemory = True 
    Else 
        ' Failed 
    End If 
End Function 
Public Function LockMemory() As Boolean 
    If (m_hMem <> 0) Then 
        If (m_lPtr = 0) Then 
            m_lPtr = GlobalLock(m_hMem) 
            If (m_lPtr <> 0) Then 
                ' Success 
                LockMemory = True 
            Else 
                ' Failed 
            End If 
        End If 
    End If 
End Function 
Public Sub UnlockMemory() 
    If (m_hMem <> 0) Then 
        If (m_lPtr <> 0) Then 
            GlobalUnlock m_hMem 
            m_lPtr = 0 
        End If 
    End If 
End Sub 
Public Sub FreeMemory() 
    If (m_hMem <> 0) Then 
        UnlockMemory 
        GlobalFree m_hMem 
    End If 
    m_hMem = 0 
End Sub 
Public Sub ReleaseDontFreeMemory() 
    ' For GMEM_DDESHARE operations... 
    UnlockMemory 
    m_hMem = 0 
End Sub 
 
Private Sub Class_Terminate() 
    FreeMemory 
End Sub