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authorAnton Samokhvalov <pg83@yandex.ru>2022-02-10 16:45:17 +0300
committerDaniil Cherednik <dcherednik@yandex-team.ru>2022-02-10 16:45:17 +0300
commitd3a398281c6fd1d3672036cb2d63f842d2cb28c5 (patch)
treedd4bd3ca0f36b817e96812825ffaf10d645803f2 /library/cpp/yson_pull/detail/varint.h
parent72cb13b4aff9bc9cf22e49251bc8fd143f82538f (diff)
downloadydb-d3a398281c6fd1d3672036cb2d63f842d2cb28c5.tar.gz
Restoring authorship annotation for Anton Samokhvalov <pg83@yandex.ru>. Commit 2 of 2.
Diffstat (limited to 'library/cpp/yson_pull/detail/varint.h')
-rw-r--r--library/cpp/yson_pull/detail/varint.h434
1 files changed, 217 insertions, 217 deletions
diff --git a/library/cpp/yson_pull/detail/varint.h b/library/cpp/yson_pull/detail/varint.h
index e75bed9a3e..38bf45d925 100644
--- a/library/cpp/yson_pull/detail/varint.h
+++ b/library/cpp/yson_pull/detail/varint.h
@@ -10,251 +10,251 @@
#include <cstddef>
#include <type_traits>
-namespace NYsonPull {
- namespace NDetail {
- namespace NVarInt {
- namespace NImpl {
- template <typename T>
- constexpr inline size_t max_size() {
- return (8 * sizeof(T) - 1) / 7 + 1;
- }
+namespace NYsonPull {
+ namespace NDetail {
+ namespace NVarInt {
+ namespace NImpl {
+ template <typename T>
+ constexpr inline size_t max_size() {
+ return (8 * sizeof(T) - 1) / 7 + 1;
+ }
- template <typename T>
- inline size_t write(ui64 value, T&& consume) {
- auto stop = false;
- auto nwritten = size_t{0};
- while (!stop) {
- ++nwritten;
- auto byte = static_cast<ui8>(value | 0x80);
- value >>= 7;
- if (value == 0) {
- stop = true;
- byte &= 0x7F;
- }
- consume(byte);
- }
- return nwritten;
- }
+ template <typename T>
+ inline size_t write(ui64 value, T&& consume) {
+ auto stop = false;
+ auto nwritten = size_t{0};
+ while (!stop) {
+ ++nwritten;
+ auto byte = static_cast<ui8>(value | 0x80);
+ value >>= 7;
+ if (value == 0) {
+ stop = true;
+ byte &= 0x7F;
+ }
+ consume(byte);
+ }
+ return nwritten;
+ }
- template <typename U>
- inline bool read_fast(byte_reader<U>& reader, ui64* value) {
- auto& buf = reader.stream().buffer();
- auto* ptr = buf.pos();
- ui32 b;
+ template <typename U>
+ inline bool read_fast(byte_reader<U>& reader, ui64* value) {
+ auto& buf = reader.stream().buffer();
+ auto* ptr = buf.pos();
+ ui32 b;
- // Splitting into 32-bit pieces gives better performance on 32-bit
- // processors.
- ui32 part0 = 0, part1 = 0, part2 = 0;
+ // Splitting into 32-bit pieces gives better performance on 32-bit
+ // processors.
+ ui32 part0 = 0, part1 = 0, part2 = 0;
- b = *(ptr++);
- part0 = (b & 0x7F);
- if (!(b & 0x80))
- goto done;
- b = *(ptr++);
- part0 |= (b & 0x7F) << 7;
- if (!(b & 0x80))
- goto done;
- b = *(ptr++);
- part0 |= (b & 0x7F) << 14;
- if (!(b & 0x80))
- goto done;
- b = *(ptr++);
- part0 |= (b & 0x7F) << 21;
- if (!(b & 0x80))
- goto done;
- b = *(ptr++);
- part1 = (b & 0x7F);
- if (!(b & 0x80))
- goto done;
- b = *(ptr++);
- part1 |= (b & 0x7F) << 7;
- if (!(b & 0x80))
- goto done;
- b = *(ptr++);
- part1 |= (b & 0x7F) << 14;
- if (!(b & 0x80))
- goto done;
- b = *(ptr++);
- part1 |= (b & 0x7F) << 21;
- if (!(b & 0x80))
- goto done;
- b = *(ptr++);
- part2 = (b & 0x7F);
- if (!(b & 0x80))
- goto done;
- b = *(ptr++);
- part2 |= (b & 0x7F) << 7;
- if (!(b & 0x80))
- goto done;
+ b = *(ptr++);
+ part0 = (b & 0x7F);
+ if (!(b & 0x80))
+ goto done;
+ b = *(ptr++);
+ part0 |= (b & 0x7F) << 7;
+ if (!(b & 0x80))
+ goto done;
+ b = *(ptr++);
+ part0 |= (b & 0x7F) << 14;
+ if (!(b & 0x80))
+ goto done;
+ b = *(ptr++);
+ part0 |= (b & 0x7F) << 21;
+ if (!(b & 0x80))
+ goto done;
+ b = *(ptr++);
+ part1 = (b & 0x7F);
+ if (!(b & 0x80))
+ goto done;
+ b = *(ptr++);
+ part1 |= (b & 0x7F) << 7;
+ if (!(b & 0x80))
+ goto done;
+ b = *(ptr++);
+ part1 |= (b & 0x7F) << 14;
+ if (!(b & 0x80))
+ goto done;
+ b = *(ptr++);
+ part1 |= (b & 0x7F) << 21;
+ if (!(b & 0x80))
+ goto done;
+ b = *(ptr++);
+ part2 = (b & 0x7F);
+ if (!(b & 0x80))
+ goto done;
+ b = *(ptr++);
+ part2 |= (b & 0x7F) << 7;
+ if (!(b & 0x80))
+ goto done;
- // We have overrun the maximum size of a Varint (10 bytes). The data
- // must be corrupt.
- return false;
+ // We have overrun the maximum size of a Varint (10 bytes). The data
+ // must be corrupt.
+ return false;
- done:
- reader.advance(ptr - buf.pos());
- *value = (static_cast<ui64>(part0)) | (static_cast<ui64>(part1) << 28) | (static_cast<ui64>(part2) << 56);
- return true;
- }
+ done:
+ reader.advance(ptr - buf.pos());
+ *value = (static_cast<ui64>(part0)) | (static_cast<ui64>(part1) << 28) | (static_cast<ui64>(part2) << 56);
+ return true;
+ }
- template <typename U>
- inline bool read_fast(byte_reader<U>& reader, ui32* value) {
- // Fast path: We have enough bytes left in the buffer to guarantee that
- // this read won't cross the end, so we can skip the checks.
- auto& buf = reader.stream().buffer();
- auto* ptr = buf.pos();
- ui32 b;
- ui32 result;
+ template <typename U>
+ inline bool read_fast(byte_reader<U>& reader, ui32* value) {
+ // Fast path: We have enough bytes left in the buffer to guarantee that
+ // this read won't cross the end, so we can skip the checks.
+ auto& buf = reader.stream().buffer();
+ auto* ptr = buf.pos();
+ ui32 b;
+ ui32 result;
- b = *(ptr++);
- result = (b & 0x7F);
- if (!(b & 0x80))
- goto done;
- b = *(ptr++);
- result |= (b & 0x7F) << 7;
- if (!(b & 0x80))
- goto done;
- b = *(ptr++);
- result |= (b & 0x7F) << 14;
- if (!(b & 0x80))
- goto done;
- b = *(ptr++);
- result |= (b & 0x7F) << 21;
- if (!(b & 0x80))
- goto done;
- b = *(ptr++);
- result |= b << 28;
- if (!(b & 0x80))
- goto done;
+ b = *(ptr++);
+ result = (b & 0x7F);
+ if (!(b & 0x80))
+ goto done;
+ b = *(ptr++);
+ result |= (b & 0x7F) << 7;
+ if (!(b & 0x80))
+ goto done;
+ b = *(ptr++);
+ result |= (b & 0x7F) << 14;
+ if (!(b & 0x80))
+ goto done;
+ b = *(ptr++);
+ result |= (b & 0x7F) << 21;
+ if (!(b & 0x80))
+ goto done;
+ b = *(ptr++);
+ result |= b << 28;
+ if (!(b & 0x80))
+ goto done;
- // FIXME
- // If the input is larger than 32 bits, we still need to read it all
- // and discard the high-order bits.
+ // FIXME
+ // If the input is larger than 32 bits, we still need to read it all
+ // and discard the high-order bits.
- for (size_t i = 0; i < max_size<ui64>() - max_size<ui32>(); i++) {
- b = *(ptr++);
- if (!(b & 0x80))
- goto done;
- }
+ for (size_t i = 0; i < max_size<ui64>() - max_size<ui32>(); i++) {
+ b = *(ptr++);
+ if (!(b & 0x80))
+ goto done;
+ }
- // We have overrun the maximum size of a Varint (10 bytes). Assume
- // the data is corrupt.
- return false;
+ // We have overrun the maximum size of a Varint (10 bytes). Assume
+ // the data is corrupt.
+ return false;
- done:
- reader.advance(ptr - buf.pos());
- *value = result;
- return true;
- }
+ done:
+ reader.advance(ptr - buf.pos());
+ *value = result;
+ return true;
+ }
- template <typename U>
- inline bool read_slow(byte_reader<U>& reader, ui64* value) {
- // Slow path: This read might cross the end of the buffer, so we
- // need to check and refresh the buffer if and when it does.
+ template <typename U>
+ inline bool read_slow(byte_reader<U>& reader, ui64* value) {
+ // Slow path: This read might cross the end of the buffer, so we
+ // need to check and refresh the buffer if and when it does.
- auto& buf = reader.stream().buffer();
- ui64 result = 0;
- int count = 0;
- ui32 b;
+ auto& buf = reader.stream().buffer();
+ ui64 result = 0;
+ int count = 0;
+ ui32 b;
- do {
- if (count == max_size<ui64>()) {
- return false;
- }
- reader.fill_buffer();
- if (reader.stream().at_end()) {
- return false;
- }
- b = *buf.pos();
- result |= static_cast<ui64>(b & 0x7F) << (7 * count);
- reader.advance(1);
- ++count;
- } while (b & 0x80);
+ do {
+ if (count == max_size<ui64>()) {
+ return false;
+ }
+ reader.fill_buffer();
+ if (reader.stream().at_end()) {
+ return false;
+ }
+ b = *buf.pos();
+ result |= static_cast<ui64>(b & 0x7F) << (7 * count);
+ reader.advance(1);
+ ++count;
+ } while (b & 0x80);
- *value = result;
- return true;
- }
+ *value = result;
+ return true;
+ }
- template <typename U>
- inline bool read_slow(byte_reader<U>& reader, ui32* value) {
- ui64 result;
- // fallback to 64-bit reading
- if (read_slow(reader, &result) && result <= std::numeric_limits<ui32>::max()) {
- *value = static_cast<ui32>(result);
- return true;
- }
+ template <typename U>
+ inline bool read_slow(byte_reader<U>& reader, ui32* value) {
+ ui64 result;
+ // fallback to 64-bit reading
+ if (read_slow(reader, &result) && result <= std::numeric_limits<ui32>::max()) {
+ *value = static_cast<ui32>(result);
+ return true;
+ }
- return false;
- }
+ return false;
+ }
- // Following functions is an adaptation
- // of Protobuf code from coded_stream.cc
- template <typename T, typename U>
- inline bool read_dispatch(byte_reader<U>& reader, T* value) {
- auto& buf = reader.stream().buffer();
+ // Following functions is an adaptation
+ // of Protobuf code from coded_stream.cc
+ template <typename T, typename U>
+ inline bool read_dispatch(byte_reader<U>& reader, T* value) {
+ auto& buf = reader.stream().buffer();
// NOTE: checking for 64-bit max_size(), since 32-bit
// read_fast() might fallback to 64-bit reading
if (buf.available() >= max_size<ui64>() ||
- // Optimization: If the Varint ends at exactly the end of the buffer,
- // we can detect that and still use the fast path.
- (!buf.is_empty() && !(buf.end()[-1] & 0x80)))
- {
- return read_fast(reader, value);
- } else {
- // Really slow case: we will incur the cost of an extra function call here,
- // but moving this out of line reduces the size of this function, which
- // improves the common case. In micro benchmarks, this is worth about 10-15%
- return read_slow(reader, value);
- }
- }
+ // Optimization: If the Varint ends at exactly the end of the buffer,
+ // we can detect that and still use the fast path.
+ (!buf.is_empty() && !(buf.end()[-1] & 0x80)))
+ {
+ return read_fast(reader, value);
+ } else {
+ // Really slow case: we will incur the cost of an extra function call here,
+ // but moving this out of line reduces the size of this function, which
+ // improves the common case. In micro benchmarks, this is worth about 10-15%
+ return read_slow(reader, value);
+ }
+ }
- }
+ }
- // Various functions to read/write varints.
+ // Various functions to read/write varints.
- // Returns the number of bytes written.
- template <typename T>
- inline NTraits::if_unsigned<T, size_t> write(ui8* data, T value) {
- return NImpl::write(
- static_cast<ui64>(value),
- [&](ui8 byte) { *data++ = byte; });
- }
+ // Returns the number of bytes written.
+ template <typename T>
+ inline NTraits::if_unsigned<T, size_t> write(ui8* data, T value) {
+ return NImpl::write(
+ static_cast<ui64>(value),
+ [&](ui8 byte) { *data++ = byte; });
+ }
- template <typename T>
- inline NTraits::if_signed<T, size_t> write(ui8* data, T value) {
- return NImpl::write(
- static_cast<ui64>(NZigZag::encode(value)),
- [&](ui8 byte) { *data++ = byte; });
- }
+ template <typename T>
+ inline NTraits::if_signed<T, size_t> write(ui8* data, T value) {
+ return NImpl::write(
+ static_cast<ui64>(NZigZag::encode(value)),
+ [&](ui8 byte) { *data++ = byte; });
+ }
- template <typename T, typename U>
- inline void write(byte_writer<U>& stream, T value) {
- ui8 data[NImpl::max_size<T>()];
- auto size = write(data, value);
- stream.write(data, size);
- }
+ template <typename T, typename U>
+ inline void write(byte_writer<U>& stream, T value) {
+ ui8 data[NImpl::max_size<T>()];
+ auto size = write(data, value);
+ stream.write(data, size);
+ }
- template <typename T, typename U>
- inline NTraits::if_unsigned<T, T> read(byte_reader<U>& reader) {
- auto value = T{};
- auto& buf = reader.stream().buffer();
- if (!buf.is_empty() && *buf.pos() < 0x80) {
- value = *buf.pos();
- reader.advance(1);
- return value;
- }
+ template <typename T, typename U>
+ inline NTraits::if_unsigned<T, T> read(byte_reader<U>& reader) {
+ auto value = T{};
+ auto& buf = reader.stream().buffer();
+ if (!buf.is_empty() && *buf.pos() < 0x80) {
+ value = *buf.pos();
+ reader.advance(1);
+ return value;
+ }
if (Y_UNLIKELY(!NImpl::read_dispatch(reader, &value))) {
- reader.fail("Error parsing varint value");
- }
- return value;
- }
+ reader.fail("Error parsing varint value");
+ }
+ return value;
+ }
- template <typename T, typename U>
- inline NTraits::if_signed<T, T> read(byte_reader<U>& reader) {
- return NZigZag::decode(
- read<NTraits::to_unsigned<T>>(reader));
- }
- }
- } // namespace NDetail
-}
+ template <typename T, typename U>
+ inline NTraits::if_signed<T, T> read(byte_reader<U>& reader) {
+ return NZigZag::decode(
+ read<NTraits::to_unsigned<T>>(reader));
+ }
+ }
+ } // namespace NDetail
+}