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Speed up countDigits

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This commit is contained in:
Alexey Milovidov 2023-02-09 04:39:12 +01:00
parent 4fd4058259
commit 8392b35d50
2 changed files with 51 additions and 76 deletions
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68
base/base/itoa.h
View File

@ -33,6 +33,41 @@
#include <base/extended_types.h>
template <typename T>
inline int digits10(T x)
{
if (x < 10ULL)
return 1;
if (x < 100ULL)
return 2;
if (x < 1000ULL)
return 3;
if (x < 1000000000000ULL)
{
if (x < 100000000ULL)
{
if (x < 1000000ULL)
{
if (x < 10000ULL)
return 4;
else
return 5 + (x >= 100000ULL);
}
return 7 + (x >= 10000000ULL);
}
if (x < 10000000000ULL)
return 9 + (x >= 1000000000ULL);
return 11 + (x >= 100000000000ULL);
}
return 12 + digits10(x / 1000000000000ULL);
}
namespace impl
{
@ -312,39 +347,6 @@ namespace convert
}
}
template <typename T>
static inline int digits10(T x)
{
if (x < 10ULL)
return 1;
if (x < 100ULL)
return 2;
if (x < 1000ULL)
return 3;
if (x < 1000000000000ULL)
{
if (x < 100000000ULL)
{
if (x < 1000000ULL)
{
if (x < 10000ULL)
return 4;
else
return 5 + (x >= 100000ULL);
}
return 7 + (x >= 10000000ULL);
}
if (x < 10000000000ULL)
return 9 + (x >= 1000000000ULL);
return 11 + (x >= 100000000000ULL);
}
return 12 + digits10(x / 1000000000000ULL);
}
template <typename T>
static inline char * writeUIntText(T x, char * p)

59
src/Functions/countDigits.cpp
View File

@ -2,9 +2,10 @@
#include <Functions/FunctionFactory.h>
#include <Functions/FunctionHelpers.h>
#include <DataTypes/DataTypesNumber.h>
#include <DataTypes/DataTypesDecimal.h>
#include <Columns/ColumnsNumber.h>
#include <Columns/ColumnDecimal.h>
#include <base/extended_types.h>
#include <base/itoa.h>
namespace DB
@ -83,7 +84,7 @@ private:
template <typename T, typename ColVecType>
static void execute(const ColVecType & col, ColumnUInt8 & result_column, size_t rows_count)
{
using NativeT = NativeType<T>;
using NativeT = make_unsigned_t<NativeType<T>>;
const auto & src_data = col.getData();
auto & dst_data = result_column.getData();
@ -92,50 +93,22 @@ private:
for (size_t i = 0; i < rows_count; ++i)
{
if constexpr (is_decimal<T>)
dst_data[i] = digits<NativeT>(src_data[i].value);
else
dst_data[i] = digits<NativeT>(src_data[i]);
}
}
template <typename T>
static UInt32 digits(T value)
{
static_assert(!is_decimal<T>);
using DivT = std::conditional_t<is_signed_v<T>, Int32, UInt32>;
UInt32 res = 0;
T tmp;
if constexpr (sizeof(T) > sizeof(Int32))
{
static constexpr const DivT e9 = 1000000000;
tmp = value / e9;
while (tmp != 0)
{
value = tmp;
tmp /= e9;
res += 9;
auto value = src_data[i].value;
if (unlikely(value < 0))
dst_data[i] = digits10<NativeT>(-static_cast<NativeT>(value));
else
dst_data[i] = digits10<NativeT>(value);
}
else
{
auto value = src_data[i];
if (unlikely(value < 0))
dst_data[i] = digits10<NativeT>(-static_cast<NativeT>(value));
else
dst_data[i] = digits10<NativeT>(value);
}
}
static constexpr const DivT e3 = 1000;
tmp = value / e3;
while (tmp != 0)
{
value = tmp;
tmp /= e3;
res += 3;
}
while (value != 0)
{
value /= 10;
++res;
}
return res;
}
};