# HG changeset patch
# User Thinker K.F. Li <thinker@codemud.net>
# Date 1309348584 -28800
# Node ID b7432d6f7e93b47b2ec9ab83cf6a3accf631734a
# Parent  9504ad530dbf723b7332ad4cf0503d82e9a254d0
adler32

diff -r 9504ad530dbf -r b7432d6f7e93 paraspace/tools.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/paraspace/tools.py	Wed Jun 29 19:56:24 2011 +0800
@@ -0,0 +1,12 @@
+base = 65521
+
+def adler32(adler, buf, offset, sz):
+    sum1 = adler & 0xffff
+    sum2 = (adler >> 16) & 0xffff
+    for off in range(offset, offset + sz):
+        sum1 = (sum1 + ord(buf[off])) % base
+        sum2 = (sum2 + sum1) % base
+        pass
+    r = (sum2 << 16) | sum1
+    return r
+