[RESOLVED] Decompress GZip

[FireXtol]

There's 2 extra characters before the zlib stream(compression info and flags), and 4 after(adler32).

http://www.ietf.org/rfc/rfc1950.txt

Or basically: strData = Chr$(&H78) & Chr$(&H9C) & strData & Adler32(strData)

Where strData was the compressed stream in the gzip stream.

I don't see customizing the flags having any real effect, so using those two characters should probably work for most any stream.

The Adler32 was simple:

Private Function B10To256(ByVal initVal As Double, ByVal Character_Return As Long, Optional ByVal DoFlip As Boolean) As String
      Dim lng As Long
      Dim bA(3) As Byte
 
    If initVal > 2147483647 Then lng = initVal - 4294967296# Else lng = initVal
    CopyMemory bA(0), lng, 4
    If DoFlip Then
      B10To256 = StrReverse(Right$(StrReverse(StrConv(bA, vbUnicode)), Character_Return))
    Else
      B10To256 = Right$(StrReverse(StrConv(bA, vbUnicode)), Character_Return)
    End If
 
End Function
 
Private Function Adler32(ByVal strIn As String) As String
Dim bString() As Byte
Dim A As Long, B As Long, X as Long
bString = StrConv(strIn, vbFromUnicode)
A = 1
For X = 0 To UBound(bString)
    A = (A + bString(X)) Mod 65521
    B = (B + A) Mod 65521
Next X
B = B * 256 + A
Adler32 = B10To256(B, 4)
End Function