two mime encoding schemes
diff --git a/Lib/base64.py b/Lib/base64.py
new file mode 100755
index 0000000..2f9bdc1
--- /dev/null
+++ b/Lib/base64.py
@@ -0,0 +1,125 @@
+# Conversions to/from base64 transport encoding as per RFC-MIME (Dec 1991
+# version).
+
+# Parameters set by RFX-XXXX.
+MAXLINESIZE = 76 # Excluding the CRLF
+INVAR = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/'
+PAD = '='
+
+# Check that I typed that string correctly...
+if len(INVAR) <> 64: raise RuntimeError, 'wrong INVAR string!?!?'
+
+# Compute the inverse table, for decode().
+inverse = {}
+for i in range(64): inverse[INVAR[i]] = i
+del i
+inverse[PAD] = 0
+
+# Encode a file.
+def encode(input, output):
+ line = ''
+ BUFSIZE = 8192
+ leftover = ''
+ while 1:
+ s = input.read(BUFSIZE)
+ if not s: break
+ s = leftover + s
+ i = 0
+ while i+3 <= len(s):
+ quad = makequad(s[i:i+3])
+ i = i+3
+ if len(line) + 4 > MAXLINESIZE:
+ output.write(line + '\n')
+ line = ''
+ line = line + quad
+ leftover = s[i:]
+ if leftover:
+ quad = makeshortquad(leftover)
+ if len(line) + 4 > MAXLINESIZE:
+ output.write(line + '\n')
+ line = ''
+ line = line + quad
+ if line:
+ output.write(line + '\n')
+
+def makequad(s): # Return the quad for a 3 character string
+ x = ord(s[0])*0x10000 + ord(s[1])*0x100 + ord(s[2])
+ x, c4 = divmod(x, 64)
+ x, c3 = divmod(x, 64)
+ c1, c2 = divmod(x, 64)
+ return INVAR[c1] + INVAR[c2] +INVAR[c3] + INVAR[c4]
+
+def makeshortquad(s): # Return the quad value for a 1 or 2 character string
+ n = len(s)
+ while len(s) < 3:
+ s = s + '\0'
+ quad = makequad(s)
+ if n == 2:
+ quad = quad[:3] + PAD
+ elif n == 1:
+ quad = quad[:2] + 2*PAD
+ return quad
+
+# Decode a file.
+def decode(input, output):
+ BUFSIZE = 8192
+ bits, n, bytes, prev = 0, 0, '', ''
+ while 1:
+ line = input.readline()
+ if not line: break
+ for c in line:
+ if inverse.has_key(c):
+ bits = bits*64 + inverse[c]
+ n = n+6
+ if n == 24:
+ triplet = decodequad(bits)
+ if c == PAD:
+ if prev == PAD:
+ triplet = triplet[:1]
+ else:
+ triplet = triplet[:2]
+ bits, n = 0, 0
+ bytes = bytes + triplet
+ if len(bytes) > BUFSIZE:
+ output.write(bytes[:BUFSIZE])
+ bytes = bytes[BUFSIZE:]
+ prev = c
+ if bytes:
+ output.write(bytes)
+
+def decodequad(bits): # Turn 24 bits into 3 characters
+ bits, c3 = divmod(bits, 256)
+ c1, c2 = divmod(bits, 256)
+ return chr(c1) + chr(c2) + chr(c3)
+
+def encodestring(s):
+ import StringIO
+ f = StringIO.StringIO(s)
+ g = StringIO.StringIO()
+ encode(f, g)
+ return g.getvalue()
+
+def decodestring(s):
+ import StringIO
+ f = StringIO.StringIO(s)
+ g = StringIO.StringIO()
+ decode(f, g)
+ return g.getvalue()
+
+# Small test program, reads stdin, writes stdout.
+# no arg: encode, any arg: decode.
+def test():
+ import sys
+ if sys.argv[1:]:
+ decode(sys.stdin, sys.stdout)
+ else:
+ encode(sys.stdin, sys.stdout)
+
+def test1():
+ s0 = "Aladdin:open sesame"
+ s1 = encodestring(s0)
+ s2 = decodestring(s1)
+ print s0, `s1`, s2
+
+if __name__ == '__main__':
+ test()