[mirrorbrain-commits] r8009 - in /trunk/mirrordoctor: setup.py zsyncmodule.c

Author: poeml
Date: Thu Mar 18 02:31:57 2010
New Revision: 8009

URL: http://svn.mirrorbrain.org/viewvc/mirrorbrain?rev=8009&view=rev
Log:
mb: 
- Added a Python extension for fast checksumming with zsync's "rsum" checksum.
  It would be far too slow, if not done in C.

Added:
    trunk/mirrordoctor/zsyncmodule.c
Modified:
    trunk/mirrordoctor/setup.py

Modified: trunk/mirrordoctor/setup.py
URL: http://svn.mirrorbrain.org/viewvc/mirrorbrain/trunk/mirrordoctor/setup.py?rev=8009&r1=8008&r2=8009&view=diff
==============================================================================
--- trunk/mirrordoctor/setup.py (original)
+++ trunk/mirrordoctor/setup.py Thu Mar 18 02:31:57 2010
_at_@ -1,9 +1,9 @@
 #!/usr/bin/env python
 
-from distutils.core import setup
+from distutils.core import setup, Extension
 
 setup(name='mirrordoctor',
-      version='2.12.0',
+      version='2.13.0',
       description='MirrorDoctor, a tool to maintain the MirrorBrain database',
       author='MirrorBrain project',
       author_email='info_at_mirrorbrain.org',
_at_@ -12,4 +12,6 @@
 
       packages=['mb'],
       scripts=['mirrordoctor.py'],
+
+      ext_modules=[Extension('zsync', sources=['zsyncmodule.c'])],
      )

Added: trunk/mirrordoctor/zsyncmodule.c
URL: http://svn.mirrorbrain.org/viewvc/mirrorbrain/trunk/mirrordoctor/zsyncmodule.c?rev=8009&view=auto
==============================================================================
--- trunk/mirrordoctor/zsyncmodule.c (added)
+++ trunk/mirrordoctor/zsyncmodule.c Thu Mar 18 02:31:57 2010
_at_@ -1,0 +1,56 @@
+/* "rsum" checksumming function from zsync's librcksum/rsum.c, version 0.6.1,
+ * wrapped into a Python extension
+ *
+ * Copyright 2010 Peter Poeml <poeml_at_mirrorbrain.org> 
+ *
+ * The checksumming function itself is available under the Artistic License;
+ * the boilerplate was a nice exercise.
+ *
+ * This is something that will be a whole lot slower when programmed in a
+ * scripting language, thus I wanted this Python extension. */
+
+#include <stdlib.h>
+#include <arpa/inet.h>
+#include "Python.h"
+
+static PyObject *zsync_rsum06(PyObject *self, PyObject *args) {
+    char *data;
+    int len;
+    unsigned short a, b;
+    unsigned char digest[4];
+    memset(digest, 0, sizeof(digest));
+
+    if (!PyArg_ParseTuple(args, "s#", &data, &len))
+        return NULL;
+
+    {
+        register unsigned short aa = 0;
+        register unsigned short bb = 0;
+        while (len) {
+            register unsigned char c = *data++;
+            aa += c;
+            bb += len * c;
+            len--;
+        }
+        a = aa;
+        b = bb;
+    }
+
+    a = htons(a);
+    b = htons(b);
+    memcpy((void *)&digest, &a, 2);
+    memcpy((void *)&digest + 2, &b, 2);
+
+    return PyString_FromStringAndSize((const char *)digest, sizeof(digest));
+}
+
+static PyMethodDef zsyncMethods[] = {
+    {"rsum06",  zsync_rsum06, METH_VARARGS, "Calculate a zsync rsum value."},
+    {NULL, NULL, 0, NULL}
+};
+
+void initzsync() {
+    Py_InitModule("zsync", zsyncMethods);
+}
+
+/* vim: set ts=4 sw=4 expandtab smarttab: */




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