Patch #1185447: binascii.b2a_qp() now correctly quotes binary characters

with ASCII value less than 32. Also, it correctly quotes dots only if
they occur on a single line, as opposed to the previous behavior of
quoting dots if they are the second character of any line.

Lib/test/test_binascii.py

@@ -148,6 +148,15 @@ class BinASCIITest(unittest.TestCase):
             "0"*75+"=\r\n=FF\r\n=FF\r\n=FF"
         )
 
+        self.assertEqual(binascii.b2a_qp('\0\n'), '=00\n')
+        self.assertEqual(binascii.b2a_qp('\0\n', quotetabs=True), '=00\n')
+        self.assertEqual(binascii.b2a_qp('foo\tbar\t\n'), 'foo\tbar=09\n')
+        self.assertEqual(binascii.b2a_qp('foo\tbar\t\n', quotetabs=True), 'foo=09bar=09\n')
+
+        self.assertEqual(binascii.b2a_qp('.'), '=2E')
+        self.assertEqual(binascii.b2a_qp('.\n'), '=2E\n')
+        self.assertEqual(binascii.b2a_qp('a.\n'), 'a.\n')
+
     def test_empty_string(self):
         # A test for SF bug #1022953.  Make sure SystemError is not raised.
         for n in ['b2a_qp', 'a2b_hex', 'b2a_base64', 'a2b_uu', 'a2b_qp',

Misc/NEWS

@@ -525,6 +525,11 @@ Library
 Extension Modules
 -----------------
 
+- Patch #1185447: binascii.b2a_qp() now correctly quotes binary characters
+  with ASCII value less than 32. Also, it correctly quotes dots only if
+  they occur on a single line, as opposed to the previous behavior of
+  quoting dots if they are the second character of any line.
+
 - Bug #1622896: fix a rare corner case where the bz2 module raised an
   error in spite of a succesful compression.
 

Modules/binascii.c

@@ -1160,12 +1160,14 @@ binascii_b2a_qp (PyObject *self, PyObject *args, PyObject *kwargs)
 		if ((data[in] > 126) ||
 		    (data[in] == '=') ||
 		    (header && data[in] == '_') ||
-		    ((data[in] == '.') && (linelen == 1)) ||
+		    ((data[in] == '.') && (linelen == 0) &&
+		     (data[in+1] == '\n' || data[in+1] == '\r' || data[in+1] == 0)) ||
 		    (!istext && ((data[in] == '\r') || (data[in] == '\n'))) ||
 		    ((data[in] == '\t' || data[in] == ' ') && (in + 1 == datalen)) ||
 		    ((data[in] < 33) &&
 		     (data[in] != '\r') && (data[in] != '\n') &&
-		     (quotetabs && ((data[in] != '\t') || (data[in] != ' ')))))
+		     (quotetabs ||
+		     	(!quotetabs && ((data[in] != '\t') && (data[in] != ' '))))))
 		{
 			if ((linelen + 3) >= MAXLINESIZE) {
 				linelen = 0;
@@ -1230,12 +1232,14 @@ binascii_b2a_qp (PyObject *self, PyObject *args, PyObject *kwargs)
 		if ((data[in] > 126) ||
 		    (data[in] == '=') ||
 		    (header && data[in] == '_') ||
-		    ((data[in] == '.') && (linelen == 1)) ||
+		    ((data[in] == '.') && (linelen == 0) &&
+		     (data[in+1] == '\n' || data[in+1] == '\r' || data[in+1] == 0)) ||
 		    (!istext && ((data[in] == '\r') || (data[in] == '\n'))) ||
 		    ((data[in] == '\t' || data[in] == ' ') && (in + 1 == datalen)) ||
 		    ((data[in] < 33) &&
 		     (data[in] != '\r') && (data[in] != '\n') &&
-		     (quotetabs && ((data[in] != '\t') || (data[in] != ' ')))))
+		     (quotetabs ||
+		     	(!quotetabs && ((data[in] != '\t') && (data[in] != ' '))))))
 		{
 			if ((linelen + 3 )>= MAXLINESIZE) {
 				odata[out++] = '=';