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333 lines
8.0 KiB
C++
333 lines
8.0 KiB
C++
#pragma once
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#include <string.h>
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#include <DB/Core/Exception.h>
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#include <DB/Core/ErrorCodes.h>
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#include <DB/Columns/IColumn.h>
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namespace DB
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{
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/** Штука для сравнения чисел.
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* Целые числа сравниваются как обычно.
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* Числа с плавающей запятой сравниваются так, что NaN-ы всегда оказываются в конце
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* (если этого не делать, то сортировка не работала бы вообще).
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*/
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template <typename T>
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struct CompareHelper
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{
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static bool less(T a, T b) { return a < b; }
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static bool greater(T a, T b) { return a > b; }
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/** Сравнивает два числа. Выдаёт число меньше нуля, равное нулю, или больше нуля, если a < b, a == b, a > b, соответственно.
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* Если одно из значений является NaN, то:
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* - если nan_direction_hint == -1 - NaN считаются меньше всех чисел;
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* - если nan_direction_hint == 1 - NaN считаются больше всех чисел;
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* По-сути: nan_direction_hint == -1 говорит, что сравнение идёт для сортировки по убыванию.
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*/
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static int compare(T a, T b, int nan_direction_hint)
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{
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return a > b ? 1 : (a < b ? -1 : 0);
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}
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};
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template <typename T>
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struct FloatCompareHelper
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{
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static bool less(T a, T b)
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{
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if (unlikely(isnan(b)))
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return !isnan(a);
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return a < b;
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}
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static bool greater(T a, T b)
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{
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if (unlikely(isnan(b)))
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return !isnan(a);
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return a > b;
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}
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static int compare(T a, T b, int nan_direction_hint)
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{
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bool isnan_a = isnan(a);
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bool isnan_b = isnan(b);
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if (unlikely(isnan_a || isnan_b))
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{
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if (isnan_a && isnan_b)
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return 0;
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return isnan_a
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? nan_direction_hint
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: -nan_direction_hint;
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}
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return (T(0) < (a - b)) - ((a - b) < T(0));
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}
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};
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template <> struct CompareHelper<Float32> : public FloatCompareHelper<Float32> {};
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template <> struct CompareHelper<Float64> : public FloatCompareHelper<Float64> {};
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/** Шаблон столбцов, которые используют для хранения std::vector.
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*/
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template <typename T>
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class ColumnVectorBase : public IColumn
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{
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private:
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typedef ColumnVectorBase<T> Self;
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public:
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typedef T value_type;
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typedef PODArray<value_type> Container_t;
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ColumnVectorBase() {}
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ColumnVectorBase(size_t n) : data(n) {}
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bool isNumeric() const { return IsNumber<T>::value; }
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bool isFixed() const { return IsNumber<T>::value; }
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size_t sizeOfField() const { return sizeof(T); }
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size_t size() const
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{
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return data.size();
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}
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StringRef getDataAt(size_t n) const
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{
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return StringRef(reinterpret_cast<const char *>(&data[n]), sizeof(data[n]));
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}
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void insertFrom(const IColumn & src, size_t n)
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{
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data.push_back(static_cast<const Self &>(src).getData()[n]);
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}
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void insertData(const char * pos, size_t length)
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{
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data.push_back(*reinterpret_cast<const T *>(pos));
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}
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void insertDefault()
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{
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data.push_back(T());
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}
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size_t byteSize() const
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{
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return data.size() * sizeof(data[0]);
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}
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int compareAt(size_t n, size_t m, const IColumn & rhs_, int nan_direction_hint) const
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{
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return CompareHelper<T>::compare(data[n], static_cast<const Self &>(rhs_).data[m], nan_direction_hint);
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}
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struct less
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{
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const Self & parent;
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less(const Self & parent_) : parent(parent_) {}
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bool operator()(size_t lhs, size_t rhs) const { return CompareHelper<T>::less(parent.data[lhs], parent.data[rhs]); }
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};
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struct greater
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{
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const Self & parent;
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greater(const Self & parent_) : parent(parent_) {}
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bool operator()(size_t lhs, size_t rhs) const { return CompareHelper<T>::greater(parent.data[lhs], parent.data[rhs]); }
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};
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void getPermutation(bool reverse, size_t limit, Permutation & res) const
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{
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size_t s = data.size();
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res.resize(s);
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for (size_t i = 0; i < s; ++i)
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res[i] = i;
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if (limit > s)
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limit = 0;
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if (limit)
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{
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if (reverse)
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std::partial_sort(res.begin(), res.begin() + limit, res.end(), greater(*this));
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else
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std::partial_sort(res.begin(), res.begin() + limit, res.end(), less(*this));
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}
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else
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{
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if (reverse)
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std::sort(res.begin(), res.end(), greater(*this));
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else
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std::sort(res.begin(), res.end(), less(*this));
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}
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}
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void reserve(size_t n)
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{
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data.reserve(n);
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}
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/** Более эффективные методы манипуляции */
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Container_t & getData()
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{
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return data;
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}
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const Container_t & getData() const
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{
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return data;
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}
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protected:
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Container_t data;
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};
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/** Реализация для числовых типов.
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* (Есть ещё ColumnAggregateFunction.)
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*/
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template <typename T>
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class ColumnVector : public ColumnVectorBase<T>
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{
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private:
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typedef ColumnVector<T> Self;
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public:
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ColumnVector() {}
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ColumnVector(size_t n) : ColumnVectorBase<T>(n) {}
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std::string getName() const { return "ColumnVector<" + TypeName<T>::get() + ">"; }
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ColumnPtr cloneEmpty() const
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{
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return new ColumnVector<T>;
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}
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Field operator[](size_t n) const
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{
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return typename NearestFieldType<T>::Type(this->data[n]);
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}
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void get(size_t n, Field & res) const
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{
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res = typename NearestFieldType<T>::Type(this->data[n]);
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}
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void insert(const Field & x)
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{
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this->data.push_back(DB::get<typename NearestFieldType<T>::Type>(x));
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}
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ColumnPtr cut(size_t start, size_t length) const
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{
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if (start + length > this->data.size())
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throw Exception("Parameters start = "
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+ toString(start) + ", length = "
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+ toString(length) + " are out of bound in IColumnVector<T>::cut() method"
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" (data.size() = " + toString(this->data.size()) + ").",
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ErrorCodes::PARAMETER_OUT_OF_BOUND);
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Self * res = new Self(length);
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memcpy(&res->getData()[0], &this->data[start], length * sizeof(this->data[0]));
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return res;
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}
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ColumnPtr filter(const IColumn::Filter & filt) const
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{
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size_t size = this->data.size();
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if (size != filt.size())
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throw Exception("Size of filter doesn't match size of column.", ErrorCodes::SIZES_OF_COLUMNS_DOESNT_MATCH);
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Self * res_ = new Self;
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ColumnPtr res = res_;
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typename Self::Container_t & res_data = res_->getData();
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res_data.reserve(size);
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for (size_t i = 0; i < size; ++i)
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if (filt[i])
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res_data.push_back(this->data[i]);
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return res;
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}
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ColumnPtr permute(const IColumn::Permutation & perm, size_t limit) const
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{
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size_t size = this->data.size();
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if (limit == 0)
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limit = size;
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else
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limit = std::min(size, limit);
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if (perm.size() < limit)
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throw Exception("Size of permutation is less than required.", ErrorCodes::SIZES_OF_COLUMNS_DOESNT_MATCH);
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Self * res_ = new Self(limit);
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ColumnPtr res = res_;
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typename Self::Container_t & res_data = res_->getData();
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for (size_t i = 0; i < limit; ++i)
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res_data[i] = this->data[perm[i]];
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return res;
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}
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ColumnPtr replicate(const IColumn::Offsets_t & offsets) const
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{
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size_t size = this->data.size();
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if (size != offsets.size())
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throw Exception("Size of offsets doesn't match size of column.", ErrorCodes::SIZES_OF_COLUMNS_DOESNT_MATCH);
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Self * res_ = new Self;
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ColumnPtr res = res_;
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typename Self::Container_t & res_data = res_->getData();
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res_data.reserve(offsets.back());
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IColumn::Offset_t prev_offset = 0;
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for (size_t i = 0; i < size; ++i)
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{
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size_t size_to_replicate = offsets[i] - prev_offset;
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prev_offset = offsets[i];
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for (size_t j = 0; j < size_to_replicate; ++j)
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res_data.push_back(this->data[i]);
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}
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return res;
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}
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void getExtremes(Field & min, Field & max) const
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{
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size_t size = this->data.size();
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if (size == 0)
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{
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min = typename NearestFieldType<T>::Type(0);
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max = typename NearestFieldType<T>::Type(0);
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return;
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}
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T cur_min = this->data[0];
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T cur_max = this->data[0];
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for (size_t i = 1; i < size; ++i)
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{
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if (this->data[i] < cur_min)
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cur_min = this->data[i];
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if (this->data[i] > cur_max)
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cur_max = this->data[i];
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}
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min = typename NearestFieldType<T>::Type(cur_min);
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max = typename NearestFieldType<T>::Type(cur_max);
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}
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};
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}
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