mirror of
https://github.com/Gamer2020/PokemonGameEditor.git
synced 2026-09-10 03:25:12 -05:00
adc0696c32
Finally got around to uploading the source code. There are still things to be done. Once a couple of things are fixed a released will be made. In the mean time people that know how to compile the program can do so but make sure to adhere to the license.
142 lines
4.8 KiB
VB.net
142 lines
4.8 KiB
VB.net
Module LZ77
|
|
Public LastStructSize As Integer
|
|
|
|
Public Function Inc(ByVal variable As Long, Optional ByVal value As Integer = 1)
|
|
Inc = variable
|
|
variable = variable + value
|
|
End Function
|
|
|
|
Private Function Dec(ByVal Source As Long)
|
|
Dec = Source
|
|
Source = Source - 1
|
|
End Function
|
|
|
|
'Decompress LZ77 data with the below function.
|
|
Public Function LZ77UnComp(ByVal Source() As Byte, ByVal Dest() As Byte) As Integer
|
|
On Error Resume Next
|
|
Dim header As Integer
|
|
header = (Source(0) Or (Source(1) * CInt(256)) Or (Source(2) * CInt(2 ^ 16)) Or (Source(3) * CInt(2 ^ 24)))
|
|
Dim i As Integer
|
|
Dim j As Integer
|
|
Dim xIn As Integer = 4
|
|
Dim xOut As Integer = 0
|
|
Dim length As Integer
|
|
Dim Offset As Integer
|
|
Dim windowOffset As Integer
|
|
Dim xLen As Integer = header \ 256
|
|
Dim retLen As Integer = xLen
|
|
Dim d As Byte
|
|
Dim data As Integer
|
|
retLen = xLen
|
|
Do While xLen > 0
|
|
d = Source(xIn)
|
|
xIn = xIn + 1
|
|
For i = 0 To 7
|
|
If (d And &H80) <> 0 Then
|
|
data = ((Source(xIn) * (2 ^ 8)) Or Source(xIn + 1))
|
|
|
|
xIn = xIn + 2
|
|
length = (data \ 4096) + 3 '(2 ^ 12)) + 3
|
|
Offset = (data And &HFFF)
|
|
windowOffset = xOut - Offset - 1
|
|
For j = 0 To length - 1
|
|
dest(xOut) = dest(windowOffset)
|
|
xOut = xOut + 1
|
|
windowOffset = windowOffset + 1
|
|
|
|
xLen = xLen - 1
|
|
If xLen = 0 Then
|
|
LZ77UnComp = retLen
|
|
Exit Function
|
|
End If
|
|
Next j
|
|
Else
|
|
dest(xOut) = Source(xIn)
|
|
xOut = xOut + 1
|
|
xIn = xIn + 1
|
|
|
|
xLen = xLen - 1
|
|
If xLen = 0 Then
|
|
LZ77UnComp = retLen
|
|
Exit Function
|
|
End If
|
|
End If
|
|
d = (d * 2) Mod 256
|
|
Next i
|
|
Loop
|
|
LZ77UnComp = retLen
|
|
LastStructSize = xIn
|
|
End Function
|
|
|
|
'Compress data to the LZ77 format with the below function.
|
|
Public Function LZ77Comp(ByVal decmpsize As Integer, ByVal Source() As Byte, ByVal dest() As Byte) As Integer
|
|
Dim i As Integer
|
|
Dim j As Integer
|
|
Dim xIn As Integer
|
|
Dim xOut As Integer
|
|
|
|
Dim length As Integer
|
|
Dim Offset As Integer
|
|
Dim tmplen As Integer
|
|
Dim tmpoff As Integer
|
|
Dim tmpxin As Integer
|
|
Dim tmpxout As Integer
|
|
Dim bufxout As Integer
|
|
Dim ctrl As Byte
|
|
Dim xdata(0 To 7, 0 To 1) As Byte
|
|
On Error GoTo endme
|
|
dest(0) = &H10 'unknown byte?
|
|
dest(1) = (decmpsize Mod 256)
|
|
dest(2) = ((decmpsize \ 256) Mod 256)
|
|
dest(3) = ((decmpsize \ (2 ^ 16)) Mod 256)
|
|
|
|
Do While (decmpsize > tmpxin)
|
|
ctrl = 0
|
|
For i = 7 To 0 Step -1
|
|
If (xIn < &H1000) Then
|
|
j = xIn
|
|
Else
|
|
j = &H1000
|
|
End If
|
|
length = 0
|
|
Offset = 0
|
|
Do While (j > 1)
|
|
tmpxin = xIn
|
|
tmpxout = (xIn - j)
|
|
Do While Source(Inc(tmpxin)) = Source(Inc(tmpxout))
|
|
If (tmpxin >= decmpsize) Then Exit Do
|
|
Loop
|
|
tmplen = (tmpxin - xIn - 1)
|
|
tmpoff = (tmpxin - tmpxout - 1)
|
|
If (tmplen > length) Then
|
|
length = tmplen
|
|
Offset = tmpoff
|
|
End If
|
|
If (length >= &H12) Then Exit Do
|
|
Inc(j, -1)
|
|
Loop
|
|
If (length >= 3) Then
|
|
ctrl = ctrl Or (1 * (2 ^ i))
|
|
If (length >= &H12) Then length = &H12
|
|
xdata(i, 0) = (((length - 3) * (2 ^ 4)) Or (Offset \ 256))
|
|
xdata(i, 1) = (Offset Mod 256)
|
|
Inc(xIn, length)
|
|
Inc(bufxout, 2)
|
|
Else
|
|
xdata(i, 0) = Source(Inc(xIn))
|
|
Inc(bufxout)
|
|
End If
|
|
Next i
|
|
dest(Inc(xOut) + 4) = ctrl
|
|
For i = 7 To 0 Step -1
|
|
dest(Inc(xOut) + 4) = xdata(i, 0)
|
|
If ((ctrl And &H80) <> 0) Then dest(Inc(xOut) + 4) = xdata(i, 1)
|
|
ctrl = (ctrl * 2) Mod 256
|
|
If (decmpsize < tmpxin) Then Exit For
|
|
Next i
|
|
Loop
|
|
endme:
|
|
LZ77Comp = xOut + 4
|
|
End Function
|
|
End Module
|