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Fix a bug in webrtc::ByteReader

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The specializations for 4-byte reading did not return correct
values. This has to do with the order of casting and shifting. Also
adding a test to expose the bug (and verify the other byte sizes).

Review URL: https://codereview.webrtc.org/1615653011

Cr-Commit-Position: refs/heads/master@{#11364}
This commit is contained in:
henrik.lundin 2016-01-24 23:47:51 -08:00 committed by Commit bot
parent f91e6d0438
commit 7a83951b27
2 changed files with 47 additions and 2 deletions
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11
webrtc/modules/rtp_rtcp/source/byte_io.h
View File

@ -310,12 +310,19 @@ class ByteReader<T, 4, false> {
public:
static T ReadBigEndian(const uint8_t* data) {
static_assert(sizeof(T) >= 4, kSizeErrorMsg);
return (data[0] << 24) | (data[1] << 16) | (data[2] << 8) | data[3];
return (Get(data, 0) << 24) | (Get(data, 1) << 16) | (Get(data, 2) << 8) |
Get(data, 3);
}
static T ReadLittleEndian(const uint8_t* data) {
static_assert(sizeof(T) >= 4, kSizeErrorMsg);
return data[0] | (data[1] << 8) | (data[2] << 16) | (data[3] << 24);
return Get(data, 0) | (Get(data, 1) << 8) | (Get(data, 2) << 16) |
(Get(data, 3) << 24);
}
private:
inline static T Get(const uint8_t* data, unsigned int index) {
return static_cast<T>(data[index]);
}
};

38
webrtc/modules/rtp_rtcp/source/byte_io_unittest.cc
View File

@ -206,5 +206,43 @@ TEST_F(ByteIoTest, Test64SBitLittleEndian) {
sizeof(int64_t)>(false);
}
// Sets up a fixed byte array and converts N bytes from the array into a
// uint64_t. Verifies the value with hard-coded reference.
TEST(ByteIo, SanityCheckFixedByteArrayUnsignedReadBigEndian) {
uint8_t data[8] = {0xFF, 0xEE, 0xDD, 0xCC, 0xBB, 0xAA, 0x99, 0x88};
uint64_t value = ByteReader<uint64_t, 2>::ReadBigEndian(data);
EXPECT_EQ(static_cast<uint64_t>(0xFFEE), value);
value = ByteReader<uint64_t, 3>::ReadBigEndian(data);
EXPECT_EQ(static_cast<uint64_t>(0xFFEEDD), value);
value = ByteReader<uint64_t, 4>::ReadBigEndian(data);
EXPECT_EQ(static_cast<uint64_t>(0xFFEEDDCC), value);
value = ByteReader<uint64_t, 5>::ReadBigEndian(data);
EXPECT_EQ(static_cast<uint64_t>(0xFFEEDDCCBB), value);
value = ByteReader<uint64_t, 6>::ReadBigEndian(data);
EXPECT_EQ(static_cast<uint64_t>(0xFFEEDDCCBBAA), value);
value = ByteReader<uint64_t, 7>::ReadBigEndian(data);
EXPECT_EQ(static_cast<uint64_t>(0xFFEEDDCCBBAA99), value);
value = ByteReader<uint64_t, 8>::ReadBigEndian(data);
EXPECT_EQ(static_cast<uint64_t>(0xFFEEDDCCBBAA9988), value);
}
// Same as above, but for little-endian reading.
TEST(ByteIo, SanityCheckFixedByteArrayUnsignedReadLittleEndian) {
uint8_t data[8] = {0xFF, 0xEE, 0xDD, 0xCC, 0xBB, 0xAA, 0x99, 0x88};
uint64_t value = ByteReader<uint64_t, 2>::ReadLittleEndian(data);
EXPECT_EQ(static_cast<uint64_t>(0xEEFF), value);
value = ByteReader<uint64_t, 3>::ReadLittleEndian(data);
EXPECT_EQ(static_cast<uint64_t>(0xDDEEFF), value);
value = ByteReader<uint64_t, 4>::ReadLittleEndian(data);
EXPECT_EQ(static_cast<uint64_t>(0xCCDDEEFF), value);
value = ByteReader<uint64_t, 5>::ReadLittleEndian(data);
EXPECT_EQ(static_cast<uint64_t>(0xBBCCDDEEFF), value);
value = ByteReader<uint64_t, 6>::ReadLittleEndian(data);
EXPECT_EQ(static_cast<uint64_t>(0xAABBCCDDEEFF), value);
value = ByteReader<uint64_t, 7>::ReadLittleEndian(data);
EXPECT_EQ(static_cast<uint64_t>(0x99AABBCCDDEEFF), value);
value = ByteReader<uint64_t, 8>::ReadLittleEndian(data);
EXPECT_EQ(static_cast<uint64_t>(0x8899AABBCCDDEEFF), value);
}
} // namespace
} // namespace webrtc