Imports System.IO
Imports System.Text
Public Class IPIP
Shared offset As Integer
Shared index As UInteger() = New UInteger(255) {}
Shared dataBuffer As Byte()
Shared indexBuffer As Byte()
Shared lastModifyTime As Long = 0L
Shared ipFile As String
Shared rwlock As New Threading.ReaderWriterLock
Shared Sub New()
Load("17monipdb.dat")
End Sub
Shared Sub Load(ByVal filename As String)
ipFile = New FileInfo(filename).FullName
Load()
End Sub
Shared Sub Load()
rwlock.AcquireWriterLock(-1)
Dim fi As New FileInfo(ipFile)
lastModifyTime = fi.LastWriteTime.Ticks
Try
dataBuffer = File.ReadAllBytes(fi.FullName)
Dim indexLength = BytesToLong(dataBuffer(0), dataBuffer(1), dataBuffer(2), dataBuffer(3))
indexBuffer = New Byte(indexLength - 1) {}
Array.Copy(dataBuffer, 4, indexBuffer, 0, indexLength)
offset = CType(indexLength, Integer)
For lp As Integer = 0 To 255
index(lp) = BytesToLong( _
indexBuffer(lp * 4 + 3), _
indexBuffer(lp * 4 + 2), _
indexBuffer(lp * 4 + 1), _
indexBuffer(lp * 4) _
)
Next
Catch ex As Exception
Throw ex
End Try
rwlock.ReleaseWriterLock()
End Sub
Private Shared Function BytesToLong(ByVal a As Byte, ByVal b As Byte, ByVal c As Byte, ByVal d As Byte) As UInteger
Return (CType(a, UInteger) << 24) Or (CType(b, UInteger) << 16) Or (CType(c, UInteger) << 8) Or d
End Function
Shared Function Find(ByVal ip As String) As String()
rwlock.AcquireReaderLock(-1)
Dim ips = ip.Split(".")
Dim ip_prefix_value = Integer.Parse(ips(0))
Dim ip2long_value As Long = BytesToLong(Byte.Parse(ips(0)), Byte.Parse(ips(1)), Byte.Parse(ips(2)), Byte.Parse(ips(3)))
Dim start = index(ip_prefix_value)
Dim max_comp_len = offset - 1028
Dim index_offset As Long = -1L
Dim index_length As Integer = -1
Dim b As Byte = 0
start = start * 8 + 1024
While start < max_comp_len
If BytesToLong(indexBuffer(start + 0), indexBuffer(start + 1), indexBuffer(start + 2), indexBuffer(start + 3)) >= ip2long_value Then
index_offset = BytesToLong(b, indexBuffer(start + 6), indexBuffer(start + 5), indexBuffer(start + 4))
index_length = &HFF And indexBuffer(start + 7)
Exit While
End If
start += 8
End While
Dim areaBytes = New Byte(index_length - 1) {}
Array.Copy(dataBuffer, offset + index_offset - 1024, areaBytes, 0, index_length)
Dim ret As String() = Encoding.UTF8.GetString(areaBytes).Split(vbTab)
rwlock.ReleaseReaderLock()
Return ret
End Function
End Class
