Clean up HpackVarintEncoder internals.
This is a follow-up to cl/254505501, which simplifies the API.
In the end, Encode() can be made static.
gfe-relnote: No functional change; not flag protected.
PiperOrigin-RevId: 254804541
Change-Id: Ide3833a1f2452df9b8f444e6aff0fca4217cc485
diff --git a/http2/hpack/tools/hpack_block_builder.cc b/http2/hpack/tools/hpack_block_builder.cc
index be62346..5b2ab75 100644
--- a/http2/hpack/tools/hpack_block_builder.cc
+++ b/http2/hpack/tools/hpack_block_builder.cc
@@ -17,8 +17,7 @@
EXPECT_LE(3, prefix_length);
EXPECT_LE(prefix_length, 8);
- HpackVarintEncoder varint_encoder;
- varint_encoder.Encode(high_bits, prefix_length, varint, &buffer_);
+ HpackVarintEncoder::Encode(high_bits, prefix_length, varint, &buffer_);
}
void HpackBlockBuilder::AppendEntryTypeAndVarint(HpackEntryType entry_type,
diff --git a/http2/hpack/varint/hpack_varint_encoder.cc b/http2/hpack/varint/hpack_varint_encoder.cc
index f69c734..63cf289 100644
--- a/http2/hpack/varint/hpack_varint_encoder.cc
+++ b/http2/hpack/varint/hpack_varint_encoder.cc
@@ -10,28 +10,11 @@
namespace http2 {
-HpackVarintEncoder::HpackVarintEncoder()
- : varint_(0), encoding_in_progress_(false) {}
-
+// static
void HpackVarintEncoder::Encode(uint8_t high_bits,
uint8_t prefix_length,
uint64_t varint,
Http2String* output) {
- unsigned char first_byte = StartEncoding(high_bits, prefix_length, varint);
- output->push_back(first_byte);
- if (!IsEncodingInProgress()) {
- return;
- }
-
- ResumeEncoding(std::numeric_limits<size_t>::max(), output);
- DCHECK(!IsEncodingInProgress());
-}
-
-unsigned char HpackVarintEncoder::StartEncoding(uint8_t high_bits,
- uint8_t prefix_length,
- uint64_t varint) {
- DCHECK(!encoding_in_progress_);
- DCHECK_EQ(0u, varint_);
DCHECK_LE(1u, prefix_length);
DCHECK_LE(prefix_length, 8u);
@@ -43,39 +26,24 @@
if (varint < prefix_mask) {
// The integer fits into the prefix in its entirety.
- return high_bits | static_cast<unsigned char>(varint);
+ unsigned char first_byte = high_bits | static_cast<unsigned char>(varint);
+ output->push_back(first_byte);
+ return;
}
- // We need extension bytes.
- varint_ = varint - prefix_mask;
- encoding_in_progress_ = true;
- return high_bits | prefix_mask;
-}
+ // Extension bytes are needed.
+ unsigned char first_byte = high_bits | prefix_mask;
+ output->push_back(first_byte);
-size_t HpackVarintEncoder::ResumeEncoding(size_t max_encoded_bytes,
- Http2String* output) {
- DCHECK(encoding_in_progress_);
- DCHECK_NE(0u, max_encoded_bytes);
-
- size_t encoded_bytes = 0;
- while (encoded_bytes < max_encoded_bytes) {
- ++encoded_bytes;
- if (varint_ < 128) {
- // Encode final seven bits, with continuation bit set to zero.
- output->push_back(varint_);
- varint_ = 0;
- encoding_in_progress_ = false;
- break;
- }
+ varint -= prefix_mask;
+ while (varint >= 128) {
// Encode the next seven bits, with continuation bit set to one.
- output->push_back(0b10000000 | (varint_ % 128));
- varint_ >>= 7;
+ output->push_back(0b10000000 | (varint % 128));
+ varint >>= 7;
}
- return encoded_bytes;
-}
-bool HpackVarintEncoder::IsEncodingInProgress() const {
- return encoding_in_progress_;
+ // Encode final seven bits, with continuation bit set to zero.
+ output->push_back(varint);
}
} // namespace http2
diff --git a/http2/hpack/varint/hpack_varint_encoder.h b/http2/hpack/varint/hpack_varint_encoder.h
index a5a9cd8..745222e 100644
--- a/http2/hpack/varint/hpack_varint_encoder.h
+++ b/http2/hpack/varint/hpack_varint_encoder.h
@@ -13,47 +13,17 @@
namespace http2 {
-// HPACK integer encoder class implementing variable length integer
-// representation defined in RFC7541, Section 5.1:
+// HPACK integer encoder class with single static method implementing variable
+// length integer representation defined in RFC7541, Section 5.1:
// https://httpwg.org/specs/rfc7541.html#integer.representation
class HTTP2_EXPORT_PRIVATE HpackVarintEncoder {
public:
- HpackVarintEncoder();
-
- // Encode |varint|, appending encoded data to |*output|. Appends between 1
- // and 11 bytes in total. Must not be called when another encoding task
- // previously started by StartEncoding() is still in progress. No encoding
- // will be in progress after this method finishes.
- void Encode(uint8_t high_bits,
- uint8_t prefix_length,
- uint64_t varint,
- Http2String* output);
-
- private:
- // Start encoding an integer. Return the first encoded byte (composed of
- // optional high bits and 1 to 8 bit long prefix). It is possible that this
- // completes the encoding. Must not be called when previously started
- // encoding is still in progress.
- unsigned char StartEncoding(uint8_t high_bits,
- uint8_t prefix_length,
- uint64_t varint);
-
- // Continue encoding the integer |varint| passed in to StartEncoding().
- // Append the next at most |max_encoded_bytes| encoded octets to |output|.
- // Returns the number of encoded octets. Must not be called unless a
- // previously started encoding is still in progress.
- size_t ResumeEncoding(size_t max_encoded_bytes, Http2String* output);
-
- // Returns true if encoding an integer has started and is not completed yet.
- bool IsEncodingInProgress() const;
-
- // The original integer shifted to the right by the number of bits already
- // encoded. The lower bits shifted away have already been encoded, and
- // |varint_| has the higher bits that remain to be encoded.
- uint64_t varint_;
-
- // True when encoding an integer has started and is not completed yet.
- bool encoding_in_progress_;
+ // Encode |varint|, appending encoded data to |*output|.
+ // Appends between 1 and 11 bytes in total.
+ static void Encode(uint8_t high_bits,
+ uint8_t prefix_length,
+ uint64_t varint,
+ Http2String* output);
};
} // namespace http2
diff --git a/http2/hpack/varint/hpack_varint_encoder_test.cc b/http2/hpack/varint/hpack_varint_encoder_test.cc
index 96ade85..fa05948 100644
--- a/http2/hpack/varint/hpack_varint_encoder_test.cc
+++ b/http2/hpack/varint/hpack_varint_encoder_test.cc
@@ -30,13 +30,11 @@
// Encode integers that fit in the prefix.
TEST(HpackVarintEncoderTest, Short) {
- HpackVarintEncoder varint_encoder;
-
for (size_t i = 0; i < HTTP2_ARRAYSIZE(kShortTestData); ++i) {
Http2String output;
- varint_encoder.Encode(kShortTestData[i].high_bits,
- kShortTestData[i].prefix_length,
- kShortTestData[i].value, &output);
+ HpackVarintEncoder::Encode(kShortTestData[i].high_bits,
+ kShortTestData[i].prefix_length,
+ kShortTestData[i].value, &output);
ASSERT_EQ(1u, output.size());
EXPECT_EQ(kShortTestData[i].expected_encoding, output[0]);
}
@@ -102,8 +100,6 @@
// Encode integers that do not fit in the prefix.
TEST(HpackVarintEncoderTest, Long) {
- HpackVarintEncoder varint_encoder;
-
// Test encoding byte by byte, also test encoding in
// a single ResumeEncoding() call.
for (size_t i = 0; i < HTTP2_ARRAYSIZE(kLongTestData); ++i) {
@@ -111,9 +107,9 @@
Http2HexDecode(kLongTestData[i].expected_encoding);
Http2String output;
- varint_encoder.Encode(kLongTestData[i].high_bits,
- kLongTestData[i].prefix_length,
- kLongTestData[i].value, &output);
+ HpackVarintEncoder::Encode(kLongTestData[i].high_bits,
+ kLongTestData[i].prefix_length,
+ kLongTestData[i].value, &output);
EXPECT_EQ(expected_encoding, output);
}
@@ -133,13 +129,11 @@
// Make sure that the encoder outputs the last byte even when it is zero. This
// happens exactly when encoding the value 2^prefix_length - 1.
TEST(HpackVarintEncoderTest, LastByteIsZero) {
- HpackVarintEncoder varint_encoder;
-
for (size_t i = 0; i < HTTP2_ARRAYSIZE(kLastByteIsZeroTestData); ++i) {
Http2String output;
- varint_encoder.Encode(kLastByteIsZeroTestData[i].high_bits,
- kLastByteIsZeroTestData[i].prefix_length,
- kLastByteIsZeroTestData[i].value, &output);
+ HpackVarintEncoder::Encode(kLastByteIsZeroTestData[i].high_bits,
+ kLastByteIsZeroTestData[i].prefix_length,
+ kLastByteIsZeroTestData[i].value, &output);
ASSERT_EQ(2u, output.size());
EXPECT_EQ(kLastByteIsZeroTestData[i].expected_encoding_first_byte,
output[0]);
@@ -149,17 +143,16 @@
// Test that encoder appends correctly to non-empty string.
TEST(HpackVarintEncoderTest, Append) {
- HpackVarintEncoder varint_encoder;
Http2String output("foo");
EXPECT_EQ(Http2HexDecode("666f6f"), output);
- varint_encoder.Encode(0b10011000, 3, 103, &output);
+ HpackVarintEncoder::Encode(0b10011000, 3, 103, &output);
EXPECT_EQ(Http2HexDecode("666f6f9f60"), output);
- varint_encoder.Encode(0b10100000, 5, 8, &output);
+ HpackVarintEncoder::Encode(0b10100000, 5, 8, &output);
EXPECT_EQ(Http2HexDecode("666f6f9f60a8"), output);
- varint_encoder.Encode(0b10011000, 3, 202147110, &output);
+ HpackVarintEncoder::Encode(0b10011000, 3, 202147110, &output);
EXPECT_EQ(Http2HexDecode("666f6f9f60a89f9f8ab260"), output);
}
