make qp_header_encoding more robust. add unittest_subject and found a strange bug. :-(

src/Makefile

@@ -16,7 +16,7 @@ libpEpMIME.a: pEpMIME.o pEpMIME_internal.o rules.o bodyparser.o \
 
 unittests: unittest_mime.o unittest_nfc.o unittest_timestamp.o \
     unittest_stringcase.o unittest_toutf8.o unittest_address.o \
-    unittest_rule.o \
+    unittest_rule.o unittest_subject.o \
     gtest-all.o gtest_main.o libpEpMIME.a
 	${CXX} -L${HOME}/local/lib/ -o $@ $^ -lpEpAdapter -lpEpEngine -lpthread
 

src/quoted_printable.cc

@@ -28,6 +28,28 @@ namespace qp
 
     const char* const hexdigit = "0123456789ABCDEF";
 
+	static const int8_t OK = 0;
+	const int8_t allowed[256] = {
+			//   1   2   3   4   5   6   7   8   9   A   B   C   D   E   F
+			__, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __,  // 0x00 .. 0x0F
+			__, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __,  // 0x10 .. 0x1F
+			__, OK, __, __, OK, __, __, __, __, __, __, __, __, OK, OK, OK,  // 0x20 .. 0x2F
+			OK, OK, OK, OK, OK, OK, OK, OK, OK, OK, __, __, __, __, __, __,  // 0x30 .. 0x3F   0x3D = '='
+			__, OK, OK, OK, OK, OK, OK, OK, OK, OK, OK, OK, OK, OK, OK, OK,  // 0x40 .. 0x4F
+			OK, OK, OK, OK, OK, OK, OK, OK, OK, OK, OK, __, __, __, OK, __,  // 0x50 .. 0x5F
+			__, OK, OK, OK, OK, OK, OK, OK, OK, OK, OK, OK, OK, OK, OK, OK,  // 0x60 .. 0x6F
+			OK, OK, OK, OK, OK, OK, OK, OK, OK, OK, OK, OK, OK, OK, OK, __,  // 0x70 .. 0x7F
+			__, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __,  // 0x80 .. 0x8F
+			__, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __,  // 0x90 .. 0x9F
+			__, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __,  // 0xA0 .. 0xAF
+			__, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __,  // 0xB0 .. 0xBF
+			__, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __,  // 0xC0 .. 0xCF
+			__, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __,  // 0xD0 .. 0xDF
+			__, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __,  // 0xE0 .. 0xEF
+			__, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __,  // 0xF0 .. 0xFF
+		};
+
+
 // decodes "quoted printable"-encoded 'input', throw if illegal character found in string
 std::string decode(const std::string& input)
 try
@@ -153,17 +175,20 @@ std::string encode_header(const std::string& input)
         }
 
         unsigned char c = input[u];
-        if(c == '=' || c=='?' || c<' ' || c>126)
+        if(allowed[c]==OK)
         {
-            char escape[] = { '=', hexdigit[c>>4], hexdigit[c & 0xF] };
-            ret.append(escape, escape+3);
-            line_length+=3;
+            ret += char(c);
+            ++line_length;
         }else if(c==' ')
         {
             ret += '_';
             ++line_length;
+        }else
+        {
+            char escape[] = { '=', hexdigit[c>>4], hexdigit[c & 0xF] };
+            ret.append(escape, escape+3);
+            line_length+=3;
         }
-        
     }
     
     return ret;

src/unittest_subject.cc

@@ -0,0 +1,57 @@
+#include "pEpMIME.hh"
+#include <pEp/message.h>
+#include <time.h>
+
+#include <gtest/gtest.h>
+
+namespace
+{
+
+struct TestEntry
+{
+	std::string encoded;
+	std::string decoded;
+};
+
+std::ostream& operator<<(std::ostream& o, const TestEntry& t)
+{
+	return o << " encoded=\"" << t.encoded << "\", decoded=\"" << t.decoded << "\" ";
+}
+
+const std::vector<TestEntry> testValues =
+	{
+		{"=?UTF-8?B?TcO2bGxlciDDnGJlcg==?=", "Möller Über"},
+		{"=?UTF-8?Q?M=C3=B6ller_=C3=9Cber?=", "Möller Über"},
+		{"=?UTF-8?Q?Hallo_Das_ist_nur_ein_Test_f=c3=bcr_eine_lange_Subject-Ze?=\r\n"
+		" =?UTF-8?Q?ile=2c_die_umgebrochen_wird=2c_da_sie_eben_viel_zu_l=c3=a4nglich_?=\r\n"
+		"  =?UTF-8?Q?geworden_ist=2e?=", 
+		"Hallo Das ist nur ein Test für eine lange Subject-Ze"
+		"ile, die umgebrochen wird, da sie eben viel zu länglich "
+		"geworden ist."},
+	};
+
+} // end of anonymous namespace
+
+
+class SubjectParserTest : public ::testing::TestWithParam<TestEntry>
+{
+	// intentionally left blank
+};
+
+INSTANTIATE_TEST_CASE_P(SubjectParserTestInstance, SubjectParserTest, testing::ValuesIn(testValues) );
+
+TEST_P( SubjectParserTest, Meh )
+{
+	const auto& v = GetParam();
+	const std::string mime_msg = 
+		"Subject: " + v.encoded + "\r\n"
+		"From: example@pep.lol\r\n"
+		"\r\n"
+		"Hallo Welt.\r\n"
+		"\r\n";
+
+	message* m = pEpMIME::parse_message( mime_msg.c_str(), mime_msg.size() );
+	ASSERT_NE( m , nullptr );
+	EXPECT_EQ( m->shortmsg , v.decoded );
+	free_message(m);
+}