Fixed #12417 -- Added signing functionality, including signing cookies. Many thanks to Simon, Stephan, Paul and everyone else involved.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@16253 bcc190cf-cafb-0310-a4f2-bffc1f526a37

1 files changed, 99 insertions, 0 deletions

diff --git a/django/utils/baseconv.py b/django/utils/baseconv.py
new file mode 100644
index 0000000000..702c172b34
--- /dev/null
+++ b/django/utils/baseconv.py
@@ -0,0 +1,99 @@
+# Copyright (c) 2010 Taurinus Collective. All rights reserved.
+# Copyright (c) 2009 Simon Willison. All rights reserved.
+# Copyright (c) 2002 Drew Perttula. All rights reserved.
+#
+# License:
+#   Python Software Foundation License version 2
+#
+# See the file "LICENSE" for terms & conditions for usage, and a DISCLAIMER OF
+# ALL WARRANTIES.
+#
+# This Baseconv distribution contains no GNU General Public Licensed (GPLed)
+# code so it may be used in proprietary projects just like prior ``baseconv``
+# distributions.
+#
+# All trademarks referenced herein are property of their respective holders.
+#
+
+"""
+Convert numbers from base 10 integers to base X strings and back again.
+
+Sample usage::
+
+  >>> base20 = BaseConverter('0123456789abcdefghij')
+  >>> base20.encode(1234)
+  '31e'
+  >>> base20.decode('31e')
+  1234
+  >>> base20.encode(-1234)
+  '-31e'
+  >>> base20.decode('-31e')
+  -1234
+  >>> base11 = BaseConverter('0123456789-', sign='$')
+  >>> base11.encode('$1234')
+  '$-22'
+  >>> base11.decode('$-22')
+  '$1234'
+
+"""
+
+BASE2_ALPHABET = '01'
+BASE16_ALPHABET = '0123456789ABCDEF'
+BASE56_ALPHABET = '23456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnpqrstuvwxyz'
+BASE36_ALPHABET = '0123456789abcdefghijklmnopqrstuvwxyz'
+BASE62_ALPHABET = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz'
+BASE64_ALPHABET = BASE62_ALPHABET + '-_'
+
+class BaseConverter(object):
+    decimal_digits = '0123456789'
+
+    def __init__(self, digits, sign='-'):
+        self.sign = sign
+        self.digits = digits
+        if sign in self.digits:
+            raise ValueError('Sign character found in converter base digits.')
+
+    def __repr__(self):
+        return "<BaseConverter: base%s (%s)>" % (len(self.digits), self.digits)
+
+    def encode(self, i):
+        neg, value = self.convert(i, self.decimal_digits, self.digits, '-')
+        if neg:
+            return self.sign + value
+        return value
+
+    def decode(self, s):
+        neg, value = self.convert(s, self.digits, self.decimal_digits, self.sign)
+        if neg:
+            value = '-' + value
+        return int(value)
+
+    def convert(self, number, from_digits, to_digits, sign):
+        if str(number)[0] == sign:
+            number = str(number)[1:]
+            neg = 1
+        else:
+            neg = 0
+
+        # make an integer out of the number
+        x = 0
+        for digit in str(number):
+            x = x * len(from_digits) + from_digits.index(digit)
+
+        # create the result in base 'len(to_digits)'
+        if x == 0:
+            res = to_digits[0]
+        else:
+            res = ''
+            while x > 0:
+                digit = x % len(to_digits)
+                res = to_digits[digit] + res
+                x = int(x / len(to_digits))
+        return neg, res
+
+base2 = BaseConverter(BASE2_ALPHABET)
+base16 = BaseConverter(BASE16_ALPHABET)
+base36 = BaseConverter(BASE36_ALPHABET)
+base56 = BaseConverter(BASE56_ALPHABET)
+base62 = BaseConverter(BASE62_ALPHABET)
+base64 = BaseConverter(BASE64_ALPHABET, sign='$')