From eb1e1c2feddb282c74dc597c4f51c5ccfe5c7fe1 Mon Sep 17 00:00:00 2001
From: Ben Firshman
Date: Mon, 25 Jan 2010 00:05:00 +0000
Subject: Added Crockford's base32 converter

---
 src/shorturls/baseconv.py            | 30 +++++++++++++++++++++++++++++-
 src/shorturls/tests/test_baseconv.py | 17 ++++++++++++++++-
 2 files changed, 45 insertions(+), 2 deletions(-)

diff --git a/src/shorturls/baseconv.py b/src/shorturls/baseconv.py
index 1e22ed1..1f1fbbd 100644
--- a/src/shorturls/baseconv.py
+++ b/src/shorturls/baseconv.py
@@ -14,6 +14,7 @@ Sample usage:
 
 class BaseConverter(object):
     decimal_digits = "0123456789"
+    decode_mapping = {}
     
     def __init__(self, digits):
         self.digits = digits
@@ -22,6 +23,14 @@ class BaseConverter(object):
         return self.convert(i, self.decimal_digits, self.digits)
     
     def to_decimal(self, s):
+        if self.decode_mapping:
+            new = ''
+            for digit in s:
+                if digit in self.decode_mapping:
+                    new += self.decode_mapping[digit]
+                else:
+                    new += digit
+            s = new
         return int(self.convert(s, self.digits, self.decimal_digits))
     
     def convert(number, fromdigits, todigits):
@@ -55,4 +64,23 @@ bin = BaseConverter('01')
 hexconv = BaseConverter('0123456789ABCDEF')
 base62 = BaseConverter(
     'ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789abcdefghijklmnopqrstuvwxyz'
-)
\ No newline at end of file
+)
+
+class Base32Converter(BaseConverter):
+    """
+    http://www.crockford.com/wrmg/base32.html
+    """
+    decode_mapping = {
+        'o': '0',
+        'i': '1',
+        'l': '1',
+    }
+    
+    def __init__(self):
+        super(Base32Converter, self).__init__('0123456789abcdefghjkmnpqrstvwxyz')
+    
+    def to_decimal(self, s):
+        return super(Base32Converter, self).to_decimal(s.lower())
+
+base32 = Base32Converter()
+
diff --git a/src/shorturls/tests/test_baseconv.py b/src/shorturls/tests/test_baseconv.py
index 5e203b7..24f944f 100644
--- a/src/shorturls/tests/test_baseconv.py
+++ b/src/shorturls/tests/test_baseconv.py
@@ -16,4 +16,19 @@ class BaseConvTests(unittest.TestCase):
         self._test_converter(baseconv.hexconv)
         
     def test_base62(self):
-        self._test_converter(baseconv.base62)
\ No newline at end of file
+        self._test_converter(baseconv.base62)
+    
+    def test_base32(self):
+        self._test_converter(baseconv.base32)
+    
+    def test_base32_mappings(self):
+        converter = baseconv.base32
+        self.assertEqual(
+            converter.from_decimal(converter.to_decimal('Fo9')),
+            'f09'
+        )
+        self.assertEqual(
+            converter.from_decimal(converter.to_decimal('43FG5i2L')),
+            '43fg5121'
+        )
+    
-- 
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