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Added bit packing for serialization of vector<bool>

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This commit is contained in:
Michael Krasnyk
2017-08-17 14:06:24 +02:00
parent 6468f55627
commit fb02a4c674
2 changed files with 106 additions and 8 deletions
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include/storage/serialization.hpp
+39 -8
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@@ -114,44 +114,75 @@ template <typename T> void write(io::FileWriter &writer, const util::vector_view
writer.WriteFrom(data.data(), count);
}
template <typename T>
inline unsigned char packBits(const T &data, std::size_t index, std::size_t count)
{
static_assert(std::is_same<typename T::value_type, bool>::value, "value_type is not bool");
unsigned char value = 0;
for (std::size_t bit = 0; bit < count; ++bit, ++index)
value = (value << 1) | data[index];
return value;
}
template <typename T>
inline void unpackBits(T &data, std::size_t index, std::size_t count, unsigned char value)
{
static_assert(std::is_same<typename T::value_type, bool>::value, "value_type is not bool");
const unsigned char mask = 1 << (count - 1);
for (std::size_t bit = 0; bit < count; value <<= 1, ++bit, ++index)
data[index] = value & mask;
}
template <> inline void read<bool>(io::FileReader &reader, util::vector_view<bool> &data)
{
const auto count = reader.ReadElementCount64();
BOOST_ASSERT(data.size() == count);
for (const auto index : util::irange<std::uint64_t>(0, count))
std::uint64_t index = 0;
for (std::uint64_t next = CHAR_BIT; next < count; index = next, next += CHAR_BIT)
{
data[index] = reader.ReadOne<bool>();
unpackBits(data, index, CHAR_BIT, reader.ReadOne<unsigned char>());
}
if (count > index)
unpackBits(data, index, count - index, reader.ReadOne<unsigned char>());
}
template <> inline void write<bool>(io::FileWriter &writer, const util::vector_view<bool> &data)
{
const auto count = data.size();
writer.WriteElementCount64(count);
for (const auto index : util::irange<std::uint64_t>(0, count))
std::uint64_t index = 0;
for (std::uint64_t next = CHAR_BIT; next < count; index = next, next += CHAR_BIT)
{
writer.WriteOne<bool>(data[index]);
writer.WriteOne<unsigned char>(packBits(data, CHAR_BIT * index, CHAR_BIT));
}
if (count > index)
writer.WriteOne<unsigned char>(packBits(data, index, count - index));
}
template <> inline void read<bool>(io::FileReader &reader, std::vector<bool> &data)
{
const auto count = reader.ReadElementCount64();
data.resize(count);
for (const auto index : util::irange<std::uint64_t>(0, count))
std::uint64_t index = 0;
for (std::uint64_t next = CHAR_BIT; next < count; index = next, next += CHAR_BIT)
{
data[index] = reader.ReadOne<bool>();
unpackBits(data, index, CHAR_BIT, reader.ReadOne<unsigned char>());
}
if (count > index)
unpackBits(data, index, count - index, reader.ReadOne<unsigned char>());
}
template <> inline void write<bool>(io::FileWriter &writer, const std::vector<bool> &data)
{
const auto count = data.size();
writer.WriteElementCount64(count);
for (const auto index : util::irange<std::uint64_t>(0, count))
std::uint64_t index = 0;
for (std::uint64_t next = CHAR_BIT; next < count; index = next, next += CHAR_BIT)
{
writer.WriteOne<bool>(data[index]);
writer.WriteOne<unsigned char>(packBits(data, index, CHAR_BIT));
}
if (count > index)
writer.WriteOne<unsigned char>(packBits(data, index, count - index));
}
}
}