Add functions for DER parsing a BIT STRING.

net/der/parser_unittest.cc

Index: net/der/parser_unittest.cc
diff --git a/net/der/parser_unittest.cc b/net/der/parser_unittest.cc
index 1943d6b86ebeb8fa79e1aa5df8147152e30d1681..10dac493978bde5deb86b344ec63e9818c5bcb51 100644
--- a/net/der/parser_unittest.cc
+++ b/net/der/parser_unittest.cc
@@ -196,6 +196,39 @@ TEST(ParserTest, CannotAdvanceAfterReadOptionalTag) {
   ASSERT_FALSE(parser.Advance());
 }
 
+TEST(ParserTest, ReadBitString) {
+  const uint8_t der[] = {0x03, 0x03, 0x01, 0xAA, 0xBE};
+  Parser parser((Input(der)));
+
+  Input bytes;
+  uint8_t unused_bits;
+  ASSERT_TRUE(parser.ReadBitString(&bytes, &unused_bits));
+  ASSERT_FALSE(parser.HasMore());

[nharper, 2015/07/21 23:23:47]

EXPECT_FALSE

[eroman, 2015/07/22 17:05:23]

Done.

+
+  ASSERT_EQ(2u, bytes.Length());
+  ASSERT_EQ(1u, unused_bits);
+  ASSERT_EQ(0xAA, bytes.UnsafeData()[0]);
+  ASSERT_EQ(0xBE, bytes.UnsafeData()[1]);

[nharper, 2015/07/21 23:23:47]

EXPECT_EQ (for lines 209-211)
Only parser.ReadBitString and bytes.Length need to ASSERT.

[eroman, 2015/07/22 17:05:23]

Done.

+}
+
+TEST(ParserTest, ReadBitString_BadTag) {
+  const uint8_t der[] = {0x05, 0x03, 0x01, 0xAA, 0xBE};
+  Parser parser((Input(der)));
+
+  Input bytes;
+  uint8_t unused_bits;
+  ASSERT_FALSE(parser.ReadBitString(&bytes, &unused_bits));
+}
+
+// Reads a BIT STRING with one unused bit -- should fail.
+TEST(ParserTest, ReadBitStringNoUnusedBits) {
+  const uint8_t der[] = {0x03, 0x03, 0x01, 0xAA, 0xBE};
+  Parser parser((Input(der)));
+
+  Input bytes;
+  ASSERT_FALSE(parser.ReadBitStringNoUnusedBits(&bytes));
+}
+
 }  // namespace test
 }  // namespace der
 }  // namespace net