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[coding] Add threadsafe get to MapUint32ToValue.

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tatiana-yan 2020-02-07 14:52:02 +03:00 • committed by mpimenov
parent 597a568787
commit 92884b48ba
2 changed files with 45 additions and 14 deletions
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2
coding/coding_tests/map_uint32_to_val_tests.cpp
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@ -55,6 +55,8 @@ UNIT_TEST(MapUint32ValTest)
uint32_t res;
TEST(table->Get(d.first, res), ());
TEST_EQUAL(res, d.second, ());
TEST(table->GetThreadsafe(d.first, res), ());
TEST_EQUAL(res, d.second, ());
}
}
}

57
coding/map_uint32_to_val.hpp
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@ -65,7 +65,10 @@
// exception of the last one) is a sequence of kBlockSize variables
// encoded by block encoding callback.
//
// On Get call kBlockSize consecutive variables are decoded and cached in RAM.
// On Get call kBlockSize consecutive variables are decoded and cached in RAM. Get is not
// threadsafe.
//
// GetThreadsafe does not use cache.
template <typename Value>
class MapUint32ToValue
@ -162,23 +165,23 @@ public:
auto & entry = m_cache[base];
if (entry.empty())
{
entry.resize(kBlockSize);
entry = GetImpl(id);
auto const start = m_offsets.select(base);
auto const end = base + 1 < m_offsets.num_ones()
? m_offsets.select(base + 1)
: m_header.m_endOffset - m_header.m_variablesOffset;
value = entry[offset];
return true;
}
std::vector<uint8_t> data(static_cast<size_t>(end - start));
// Tries to get |value| for key identified by |id|. Returns
// false if table does not have entry for this id.
WARN_UNUSED_RESULT bool GetThreadsafe(uint32_t id, Value & value) const
{
if (id >= m_ids.size() || !m_ids[id])
return false;
m_reader.Read(m_header.m_variablesOffset + start, data.data(), data.size());
uint32_t const rank = static_cast<uint32_t>(m_ids.rank(id));
uint32_t const offset = rank % kBlockSize;
MemReader mreader(data.data(), data.size());
NonOwningReaderSource msource(mreader);
m_readBlockCallback(msource, kBlockSize, entry);
}
auto const entry = GetImpl(id);
value = entry[offset];
return true;
@ -219,6 +222,32 @@ public:
uint64_t Count() const { return m_ids.num_ones(); }
private:
std::vector<Value> GetImpl(uint32_t id) const
{
ASSERT_LESS(id, m_ids.size(), ());
ASSERT(m_ids[id], ());
uint32_t const rank = static_cast<uint32_t>(m_ids.rank(id));
uint32_t const base = rank / kBlockSize;
std::vector<Value> values(kBlockSize);
auto const start = m_offsets.select(base);
auto const end = base + 1 < m_offsets.num_ones()
? m_offsets.select(base + 1)
: m_header.m_endOffset - m_header.m_variablesOffset;
std::vector<uint8_t> data(static_cast<size_t>(end - start));
m_reader.Read(m_header.m_variablesOffset + start, data.data(), data.size());
MemReader mreader(data.data(), data.size());
NonOwningReaderSource msource(mreader);
m_readBlockCallback(msource, kBlockSize, values);
return values;
}
bool Init()
{
m_header.Read(m_reader);