INTERNATIONAL PATCHING SYSTEM ( GBA ROM TOOLS ) : APPLIQUER OU CRÉER UN PATCH IPS

  Private Sub createips(ByVal chemin1 As String, ByVal chemin2 As String, ByVal chemin3 As String)
        Dim ips As String
        Dim ipsz() As Byte
        '     Try
        Dim hbread1 As New BinaryReader(File.OpenRead(chemin1))
        Dim hbread2 As New BinaryReader(File.OpenRead(chemin2))
        Dim smallestfile As Integer
        Dim F_array1(FileLen(chemin1) - 1) As Byte
        Dim F_array2(FileLen(chemin2) - 1) As Byte
        hbread1.BaseStream.Seek(0, SeekOrigin.Begin)
        hbread1.Read(F_array1, 0, FileLen(chemin1))
        hbread1.BaseStream.Flush()
        hbread1.Close()
        hbread2.BaseStream.Seek(0, SeekOrigin.Begin)
        hbread2.Read(F_array2, 0, FileLen(chemin2))
        hbread2.BaseStream.Flush()
        hbread2.Close()
        Dim maxi As Long
        Dim mini As Long
        Dim isastring As Boolean
        Dim n As Long
        Dim intlength As Integer
        Dim tmp As String
        Dim tmp2 As String
        Dim tmpstring As String

        If F_array1.GetUpperBound(0) > F_array2.GetUpperBound(0) Then
            maxi = F_array1.GetUpperBound(0)
            mini = F_array2.GetUpperBound(0)
        End If
        If F_array1.GetUpperBound(0) < F_array2.GetUpperBound(0) Then
            'Si le fichier modifié est + gros que le fichier source
            'on commence le fichier ips (par la fin) en ecrivant les octets suplémentaire 
            'suivi de la traditionel syntaxe offset sur 3 bytes, length sur 2 bytes
            maxi = F_array2.GetUpperBound(0)
            mini = F_array1.GetUpperBound(0)
            For n = maxi To mini + 1 Step -1

                tmpstring = Convert.ToChar(F_array2(n)) & tmpstring
                intlength += 1
            Next
            tmp = convertfrombase10(mini + 1).PadLeft(6, "0")
            tmp2 = convertfrombase10(intlength).PadLeft(4, "0")
            ips = Convert.ToChar(convertfrombase16(tmp.Substring(0, 2))) & _
   Convert.ToChar(convertfrombase16(tmp.Substring(2, 2))) & _
   Convert.ToChar(convertfrombase16(tmp.Substring(4, 2))) & _
   Convert.ToChar(convertfrombase16(tmp2.Substring(0, 2))) & _
   Convert.ToChar(convertfrombase16(tmp2.Substring(2, 2))) & tmpstring
        End If
        If F_array1.GetUpperBound(0) = F_array2.GetUpperBound(0) Then
            maxi = F_array2.GetUpperBound(0)
            mini = F_array2.GetUpperBound(0)
        End If

        intlength = 0


        For n = mini To 0 Step -1
            If F_array1(n) <> F_array2(n) Then 'si les deux octets sont differents :
                If isastring = False Then
                    intlength = 1
                    tmp2 = convertfrombase10(intlength).PadLeft(4, "0")
                    tmp = convertfrombase10(n).PadLeft(6, "0")
                    tmpstring = Convert.ToChar(F_array2(n))
                    isastring = True
                Else
                    'si isastring = true c'est que le caractere precedent etait different lui aussi
                    intlength += 1
                    tmp2 = convertfrombase10(intlength).PadLeft(4, "0")
                    tmp = convertfrombase10(n).PadLeft(6, "0")
                    tmpstring = Convert.ToChar(F_array2(n)) & tmpstring
                End If
                isastring = True
            Else
                If intlength >= 1 Then
                    'on ecrit offset sur 3 bytes, length sur 2 bytes puis l'(les) octet(s)
                    'different(s) au debut de la variable ips (on ecrit le fichier à l'envers)
                    ips = Convert.ToChar(convertfrombase16(tmp.Substring(0, 2))) & _
   Convert.ToChar(convertfrombase16(tmp.Substring(2, 2))) & _
   Convert.ToChar(convertfrombase16(tmp.Substring(4, 2))) & _
   Convert.ToChar(convertfrombase16(tmp2.Substring(0, 2))) & _
   Convert.ToChar(convertfrombase16(tmp2.Substring(2, 2))) & tmpstring & ips
                End If
                isastring = False
                intlength = 0
            End If
        Next
        ips = "PATCH" & ips & "EOF"

        'on ecrit au sens propre le fichier
        Dim F_array3(ips.Length - 1) As Byte
        For n = 0 To ips.Length - 1
            F_array3(n) = Convert.ToByte(ips.Chars(n))
        Next
        Dim hbwrite As New BinaryWriter(File.OpenWrite(chemin3))
        hbwrite.BaseStream.Seek(0, SeekOrigin.Begin)
        hbwrite.Write(F_array3, 0, ips.Length)
        hbwrite.BaseStream.Flush()
        hbwrite.Flush()
        hbwrite.Close()
        MsgBox("Ips creation succesful")
        '      Catch ex As Exception
        '         MsgBox(ex.Message)
        '       End Try
    End Sub

    Private Sub apply_ips(ByVal chemin1 As String, ByVal chemin2 As String, ByVal chemin3 As String)
        Dim ips As String
        Dim ipsz() As Byte
        Dim n As Integer
        '   Try
        Dim hbread1 As New BinaryReader(File.OpenRead(chemin1))
        Dim hbread2 As New BinaryReader(File.OpenRead(chemin2))
        Dim F_array1(FileLen(chemin1) - 1) As Byte
        Dim F_array2(FileLen(chemin2) - 1) As Byte
        hbread1.BaseStream.Seek(0, SeekOrigin.Begin)
        hbread1.Read(F_array1, 0, FileLen(chemin1))
        hbread1.BaseStream.Flush()
        hbread1.Close()
        hbread2.BaseStream.Seek(0, SeekOrigin.Begin)
        hbread2.Read(F_array2, 0, FileLen(chemin2))
        hbread2.BaseStream.Flush()
        hbread2.Close()
        Dim patch As String
        Dim tmphexoffset As String
        Dim tmphexlength As String
        Dim tmplength As Integer
        Dim tmpoffset As Integer
        Dim tmpstring As String
        Dim m As Integer
        Dim a As Integer
        Dim l As Integer
        patch = Convert.ToChar(F_array2(0)) & Convert.ToChar(F_array2(1)) & Convert.ToChar(F_array2(2)) & Convert.ToChar(F_array2(3)) & Convert.ToChar(F_array2(4))
        If patch = "PATCH" Then
            n = 5
            Do
                'on lit dans tmphexoffset les 3 prochains octets, qui represente 
                'l'offset des octets à modifier
                tmphexoffset = convertfrombase10(F_array2(n)).PadLeft(2, "0") & convertfrombase10(F_array2(n + 1)).PadLeft(2, "0") & convertfrombase10(F_array2(n + 2)).PadLeft(2, "0")
                'si on rencontre les 3 octets E O F , on sort de la boucle
                If tmphexoffset = "454f46" And n >= F_array2.Length - 4 Then Exit Do
                'on lit dans tmphexlength les 2 prochains octets, qui represente
                'la taille des octets à modifier
                tmphexlength = convertfrombase10(F_array2(n + 3)).PadLeft(2, "0") & convertfrombase10(F_array2(n + 4)).PadLeft(2, "0")
                '(conversions)
                tmplength = convertfrombase16(tmphexlength)
                tmpoffset = convertfrombase16(tmphexoffset)
                tmpstring = ""
                'on lit maintenant les octets a modifier dans tmpstring
                For m = n + 5 To n + 5 + tmplength - 1
                    tmpstring += Convert.ToChar(F_array2(m))
                Next
                l = 0
                'si les octets sont a ecrire plus loin que la fin du fichier, on agrandi le tableau
                If (tmpoffset + tmplength - 1) > F_array1.Length Then ReDim Preserve F_array1(tmpoffset + tmplength - 1)
                'on modifie les octets lues precedements dans le tableau de byte du fichier à patcher
                For a = tmpoffset To tmpoffset + tmplength - 1
                    F_array1(a) = Convert.ToByte(tmpstring.Chars(l))
                    l += 1
                Next
                n = n + 5 + tmplength
            Loop
            'on ecrit le tableau
            Dim hbwrite As New BinaryWriter(File.OpenWrite(chemin3))
            hbwrite.BaseStream.Seek(0, SeekOrigin.Begin)
            hbwrite.Write(F_array1, 0, F_array1.Length)
            hbwrite.BaseStream.Flush()
            hbwrite.Flush()
            hbwrite.Close()
        Else
            MsgBox("bad ips file")
        End If
        MsgBox("Ips patching succesful")
        '       Catch ex As Exception
        '           MsgBox(ex.Message)
        '       End Try
    End Sub

    Public Function convertfrombase16(ByVal hexa As String) As Integer
        Return Convert.ToInt64(hexa, 16) 'converti en type int64(equivalent de long) et en base 10 la valeur de "hexa" à partir d'une base 16 
    End Function

    Public Function convertfrombase10(ByVal dec As Integer) As String
        Return Convert.ToString(dec, 16)  'converti la valeur Long de "dec" en base 16
    End Function