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'---------------------------------------------------------------------------------------
' Module : cCallAPIByName
' DateTime : 31/08/2008 19:40
' Author : Cobein
' Mail : cobein27@hotmail.com
' WebPage : http://www.advancevb.com.ar
' Purpose : Call APIs by name
' Usage : At your own risk
' Requirements: None
' Distribution: You can freely use this code in your own
' applications, but you may not reproduce
' or publish this code on any web site,
' online service, or distribute as source
' on any media without express permission.
'
' Credits : Arne Elster, original callpointer function.
'
' History : 31/08/2008 First Cut....................................................
'---------------------------------------------------------------------------------------
Option Explicit
Private Declare Sub CpyMem Lib "kernel32" Alias "RtlMoveMemory" (pDst As Any, pSrc As Any, ByVal dlen As Long)
Private Declare Function GetProcAddress Lib "kernel32" (ByVal hModule As Long, ByVal lpProcName As String) As Long
Private Declare Function LoadLibraryA Lib "kernel32" (ByVal lpLibFileName As String) As Long
Public Function DoNotCall() As Long
'
End Function
Public Function CallAPIByName(ByVal sLib As String, ByVal sMod As String, ParamArray Params()) As Long
Dim lPtr As Long
Dim bvASM(&HEC00& - 1) As Byte
Dim i As Long
Dim lMod As Long
lMod = GetProcAddress(LoadLibraryA(sLib), sMod)
If lMod = 0 Then Exit Function
lPtr = VarPtr(bvASM(0))
CpyMem ByVal lPtr, &H59595958, &H4: lPtr = lPtr + 4
CpyMem ByVal lPtr, &H5059, &H2: lPtr = lPtr + 2
For i = UBound(Params) To 0 Step -1
CpyMem ByVal lPtr, &H68, &H1: lPtr = lPtr + 1
CpyMem ByVal lPtr, CLng(Params(i)), &H4: lPtr = lPtr + 4
Next
CpyMem ByVal lPtr, &HE8, &H1: lPtr = lPtr + 1
CpyMem ByVal lPtr, lMod - lPtr - 4, &H4: lPtr = lPtr + 4
CpyMem ByVal lPtr, &HC3, &H1
Dim lVTE As Long
Dim lRet As Long
CpyMem lVTE, ByVal ObjPtr(Me), &H4
lVTE = lVTE + &H1C
CpyMem lRet, ByVal lVTE, &H4
CpyMem ByVal lVTE, VarPtr(bvASM(0)), &H4
CallAPIByName = DoNotCall
CpyMem ByVal lVTE, lRet, &H4
End Function
He empezado a estudiar este source para llamar a apis sin declararlas pero tengo problemas para entender como funciona. Parece que usa asm para pushear los parametros en el stack? Las instrucciones asm estan en opcodes? Me gustaria que alguien me ayudara un poco a entender por completo el codigo que me parece muy interesante.
Un saludo