From a0fc644165cdcedfc430cb84c38f87fc960515a0 Mon Sep 17 00:00:00 2001
From: tv <tv@shackspace.de>
Date: Wed, 4 Mar 2015 20:17:18 +0100
Subject: import mime-0.4.0.1

commit 013ab26ccb84ddec5eed3ba42d8648b32dc79b38
---
 Codec/MIME/QuotedPrintable.hs | 66 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 66 insertions(+)
 create mode 100644 Codec/MIME/QuotedPrintable.hs

(limited to 'Codec/MIME/QuotedPrintable.hs')

diff --git a/Codec/MIME/QuotedPrintable.hs b/Codec/MIME/QuotedPrintable.hs
new file mode 100644
index 0000000..cdc2266
--- /dev/null
+++ b/Codec/MIME/QuotedPrintable.hs
@@ -0,0 +1,66 @@
+--------------------------------------------------------------------
+-- |
+-- Module    : Codec.MIME.QuotedPrintable
+-- Copyright : (c) 2006-2009, Galois, Inc. 
+-- License   : BSD3
+--
+-- Maintainer: Sigbjorn Finne <sigbjorn.finne@gmail.com>
+-- Stability : provisional
+-- Portability:
+--
+-- To and from QP content encoding.
+--
+--------------------------------------------------------------------
+module Codec.MIME.QuotedPrintable 
+       ( decode -- :: String -> String
+       , encode -- :: String -> String
+       ) where
+
+import Data.Char
+
+-- | 'decode' incoming quoted-printable content, stripping
+-- out soft line breaks and translating @=XY@ sequences
+-- into their decoded byte\/octet. The output encoding\/representation 
+-- is still a String, not a sequence of bytes.
+decode :: String -> String
+decode "" = ""
+decode ('=':'\r':'\n':xs) = decode xs -- soft line break.
+decode ('=':x1:x2:xs)
+ | isHexDigit x1 && isHexDigit x2 =
+    chr (digitToInt x1 * 16 + digitToInt x2) : decode xs
+decode ('=':xs) = '=':decode xs
+              -- make it explicit that we propagate other '=' occurrences.
+decode (x1:xs) = x1:decode xs
+
+-- | 'encode' converts a sequence of characeter _octets_ into
+-- quoted-printable form; suitable for transmission in MIME
+-- payloads. Note the stress on _octets_; it is assumed that
+-- you have already converted Unicode into a <=8-bit encoding
+-- (UTF-8, most likely.)
+encode :: String -> String
+encode xs = encodeLength 0 xs
+
+-- | @encodeLength llen str@ is the worker function during encoding.
+-- The extra argument @llen@ tracks the current column for the line
+-- being processed. Soft line breaks are inserted if a line exceeds
+-- a max length.
+encodeLength :: Int -> String -> String
+encodeLength _ "" = ""
+encodeLength n (x:xs)
+ | n >= 72  = '=':'\r':'\n':encodeLength 0 (x:xs)
+encodeLength _ ('=':xs) 
+ = '=':'3':'D':encodeLength 0 xs
+encodeLength n (x:xs)
+ | ox >= 0x100 = error ("QuotedPrintable.encode: encountered > 8 bit character: " ++ show (x,ox))
+ | n >= 72     = '=':'\r':'\n':encodeLength 0 (x:xs)
+ | ox >= 0x21 && ox <= 0x7e = x : encodeLength (n+1) xs
+ | ox == 0x09 || ox == 0x20 = x : encodeLength (n+1) xs
+ | otherwise = '=':showH (ox `div` 0x10): showH (ox `mod` 0x10):encodeLength (n+3) xs
+ where
+  ox = ord x
+  showH v
+   | v < 10    = chr (ord_0 + v)
+   | otherwise = chr (ord_A + (v-10))
+   
+  ord_0 = ord '0'
+  ord_A = ord 'A'
-- 
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