delphi - InStrB VB6 到 Delphi

Question

我有一个VB6代码需要转换为Delphi代码，所有代码都已转换，但是当我遇到InstrB时，我在delphi中找不到任何等效的函数。 VB6的InStrB有与delphi等效的代码吗？

这是 VB6 代码:

'Author: John Kozee
'Purpose: Enumerate Label captions given a known hWnd
'Date: June 12, 2004
Option Explicit

Private Declare Function GetClassName Lib "user32" Alias "GetClassNameA" (ByVal hwnd As Long, ByVal lpClassName As String, ByVal nMaxCount As Long) As Long
Private Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" (Destination As Any, Source As Any, ByVal Length As Long)
Private Const VBM_WINDOWTITLEADDR = &H1091
Private Declare Function SendMessage Lib "USER32.DLL" Alias "SendMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, wParam As Any, lParam As Any) As Long

Private Declare Function GetWindowThreadProcessId Lib "user32" (ByVal hwnd As Long, lpdwProcessId As Long) As Long
Private Declare Function OpenProcess Lib "kernel32" (ByVal dwDesiredAccess As Long, ByVal blnheritHandle As Long, ByVal dwAppProcessId As Long) As Long
Private Declare Function CloseHandle Lib "kernel32" (ByVal hObject As Long) As Long
Private Const MEM_PRIVATE = &H20000
Private Const MEM_COMMIT = &H1000

Private Const PROCESS_VM_READ = (&H10)
Private Const PROCESS_VM_WRITE = (&H20)
Private Const PROCESS_VM_OPERATION = (&H8)
Private Const PROCESS_QUERY_INFORMATION = (&H400)
Private Const PROCESS_READ_WRITE_QUERY = PROCESS_VM_READ + PROCESS_VM_WRITE + PROCESS_VM_OPERATION + PROCESS_QUERY_INFORMATION

Private Type MEMORY_BASIC_INFORMATION ' 28 bytes
    BaseAddress As Long
    AllocationBase As Long
    AllocationProtect As Long
    RegionSize As Long
    State As Long
    Protect As Long
    lType As Long
End Type
Private Declare Function VirtualQueryEx& Lib "kernel32" (ByVal hProcess As Long, lpAddress As Any, lpBuffer As MEMORY_BASIC_INFORMATION, ByVal dwLength As Long)
Private Declare Function ReadProcessMemory Lib "kernel32" (ByVal hProcess As Long, lpBaseAddress As Any, lpBuffer As Any, ByVal nSize As Long, lpNumberOfBytesWritten As Long) As Long

Private abBuffer() As Byte 'Heap Buffer
Private lBaseAddress As Long
Private hProcess As Long

Public Sub GetFormLabels(hwnd As Long, OutData As String)
    Dim sClass As String
    Dim lRet As Long
    Dim pid As Long
    Dim hProcess As Long
    Dim lFormCaptionHeapAddress As Long

    Dim lpMem As Long
    Dim lLenMBI As Long
    Dim lBytesRead As Long
    Dim mbi As MEMORY_BASIC_INFORMATION

    'Make sure we are working with a VB Form hWnd
    sClass = Space(256)
    lRet = GetClassName(hwnd, sClass, 255)
    sClass = Left(sClass, lRet)
    If Not sClass = "ThunderRT6FormDC" Then
        MsgBox "This function only works on VB RunTime 6 Forms ThunderFormRT6DC"
        Exit Sub
    End If

    'Now get the internal heap address of the form caption.  All that we need can be found in this heap (hopefully!)
    'This is done with a little undocumented SendMessage magic
    lFormCaptionHeapAddress = SendMessage(hwnd, VBM_WINDOWTITLEADDR, ByVal 0&, ByVal 0&)

    'Get a handle on the process with required access
    lRet = GetWindowThreadProcessId(hwnd, pid)
    If pid = 0 Then
        MsgBox "Unable to determine pid of this hwnd."
        Exit Sub
    End If
    hProcess = OpenProcess(PROCESS_READ_WRITE_QUERY, False, pid)

    'Get the Heap at the caption point
    lLenMBI = Len(mbi)
    lpMem = lFormCaptionHeapAddress
    mbi.AllocationBase = lpMem
    mbi.BaseAddress = lpMem
    lRet = VirtualQueryEx(hProcess, ByVal lpMem, mbi, lLenMBI)
    If lRet <> lLenMBI Then GoTo Finished

    'Now go back and get the entire heap
    lBaseAddress = mbi.AllocationBase
    lpMem = lBaseAddress
    mbi.BaseAddress = lBaseAddress
    mbi.RegionSize = 0
    lRet = VirtualQueryEx(hProcess, ByVal lpMem, mbi, lLenMBI)
    If lRet <> lLenMBI Then GoTo Finished

    'A couple of sanity checks, just to be safe
    If Not ((mbi.lType = MEM_PRIVATE) And (mbi.State = MEM_COMMIT) And mbi.RegionSize > 0) Then
        MsgBox "Unexpected Heap Type, State, or Size."
        GoTo Finished
    End If

    'Allocate a buffer and read it in
    ReDim abBuffer(0 To mbi.RegionSize - 1)
    ReadProcessMemory hProcess, ByVal mbi.BaseAddress, abBuffer(LBound(abBuffer)), mbi.RegionSize, lBytesRead

    'So far, so good.  Things get messy from here.  We have to
    'do some manual parsing of the buffer to get what we are after.  To
    'make things easier, I'll will get every label on every form in the
    'exe.  Otherwise, you will need to first find the form that is
    'reference the caption.  Then find every label between it and the next
    'form.

    Dim iCnt As Integer
    Dim al() As Long
    Debug.Print "start"
    'Print all of the label captions
    If EnumVBObjectPtrs("VB.Label", 44, al) > 0 Then
        For iCnt = LBound(al) To UBound(al)
            OutData = OutData & "|Hit at: " & Hex(al(iCnt) + lBaseAddress + 44) & " Object At: " & Hex(al(iCnt) + lBaseAddress) & " Caption =: " & GetLabelCaption(al(iCnt))
        Next iCnt
    End If

Finished:
    CloseHandle hProcess
    abBuffer() = ""
End Sub

Private Function GetLabelCaption(lpLocalObjPtr As Long) As String
    Dim lStrPtr As Long

    'Get local pointer to caption
    CopyMemory lStrPtr, abBuffer(lpLocalObjPtr + 136), 4
    lStrPtr = lStrPtr - lBaseAddress

    'Get caption
    If lStrPtr <> 0 Then
        GetLabelCaption = StrConv(MidB(abBuffer, lStrPtr + 1, 260), vbUnicode)
    End If
    GetLabelCaption = Left$(GetLabelCaption, InStr(GetLabelCaption, vbNullChar) - 1)
End Function

'This function will search the buffer for a given VBObjectIDString, then
'find the start of that control by searching for a refence to it in the 600
'bytes prior.
'It then finds any object of that type by searching the buffer for any
'references to the Heap Location of that control, and adds it to the enumeration
'if the reference hit position is at the correct offset (pos-offset = lBaseAddress)
'setting the EnumObj entry to the start location (local buffer address) and
'returns the counrt
Private Function EnumVBObjectPtrs(VBObjectIDString As String, _
                                  lOffset As Long, _
                                  EnumObj() As Long) As Integer
    Dim abObjectPtr(0 To 3) As Byte 'LittleEndian byte array of the Heap Address of the VBObject
    Dim abBaseAddress(0 To 3) As Byte 'LittleEndian byte array of the Heap Base Memory Address
    Dim abLong(0 To 3) As Byte 'Byte array for ptr manipulation
    Dim lPtr As Long 'Local Buffer pointer for search hits
    Dim lHeapPtr As Long 'Heap pointer (lPtr + lBaseAddress)
    Dim iCnt As Integer
    Dim alRet() As Long
    Dim iPos As Long


    'Find the location of the VBObjectIDString string
    Dim Val
    Val = StrConv(VBObjectIDString, vbFromUnicode)
    MsgBox Val

    lPtr = InStrB(1, abBuffer, Val) - 1
    lHeapPtr = lBaseAddress + lPtr
    If lPtr = 0 Then Exit Function

    'We now need to find the location that points to the start of the object
    'which should be 244 bytes prior (on XP at least) we go back 300 just in
    'case.  This is at offset 36, so we'll need to adjust back to the beginning
    'of the object
    CopyMemory abLong(0), lHeapPtr, 4
    lPtr = InStrB(lPtr - 600, abBuffer, abLong) - 1
    If lPtr = 0 Then Exit Function
    lPtr = lPtr - 36 'Adjust back to the beginning of the object
    lHeapPtr = lBaseAddress + lPtr
    CopyMemory abObjectPtr(0), lHeapPtr, 4

    'Turn the lBaseAddress into LittleEndian byte array for searching
    CopyMemory abBaseAddress(0), lBaseAddress, 4

    'Loop through the buffer
    lPtr = 1
    Do Until lPtr = 0
        'Find a reference to this object
        lPtr = InStrB(lPtr, abBuffer, abObjectPtr)

        If lPtr > 0 Then
            'make sure that this is really a VB object
            'move back from the offset of the object
            'and make sure that it has the correct base memory value
            iPos = InStrB(lPtr - lOffset - 1, abBuffer, abBaseAddress)
            If iPos = lPtr - lOffset Then
                ReDim Preserve alRet(0 To iCnt)
                alRet(iCnt) = lPtr - lOffset - 1
                iCnt = iCnt + 1
            End If
            'Keep searching from the next byte
            lPtr = lPtr + 1
        End If
    Loop

    EnumVBObjectPtrs = iCnt
    EnumObj = alRet

End Function

Answer 1

此函数通常用于搜索字符串中的子字符串。所以我猜想可能的等价物是Pos。另一方面，也许您的代码是在字节数组而不是文本上运行的。在这种情况下，答案可能会有所不同。我不知道与 Pos 等效的二进制文件，但编写一个非常容易。

即使经过您的编辑，我们也没有太多背景信息。你知道这段代码吗？你知道它在做什么吗？它操作什么数据类型等等。如果您可以提供此类详细信息，那么也许您会得到更明确的答案。

更新

考虑到您对问题的最新编辑，代码似乎正在使用 InStrB 来搜索字节数组中的特定模式。您需要编写一个 Delphi 辅助函数来执行此操作，因为我不相信标准运行时库具有这样的函数。