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80 lines
1.9 KiB
C++
80 lines
1.9 KiB
C++
#pragma once
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#include <string.h>
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#include <DB/Columns/ColumnArray.h>
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#include <DB/Columns/ColumnsNumber.h>
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namespace DB
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{
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/** Cтолбeц значений типа "строка".
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* Отличается от массива UInt8 только получением элемента (в виде String, а не Array)
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*/
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class ColumnString : public ColumnArray
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{
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private:
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ColumnUInt8::Container_t & char_data;
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public:
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/** Создать пустой столбец строк, с типом значений */
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ColumnString()
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: ColumnArray(new ColumnUInt8()),
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char_data(dynamic_cast<ColumnUInt8 &>(*data).getData())
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{
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}
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std::string getName() const { return "ColumnString"; }
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ColumnPtr cloneEmpty() const
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{
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return new ColumnString;
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}
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Field operator[](size_t n) const
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{
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size_t offset = n == 0 ? 0 : offsets[n - 1];
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size_t size = offsets[n] - offset - 1;
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const char * s = reinterpret_cast<const char *>(&dynamic_cast<const ColumnUInt8 &>(*data).getData()[offset]);
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return String(s, size);
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}
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void insert(const Field & x)
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{
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const String & s = boost::get<const String &>(x);
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size_t old_size = char_data.size();
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size_t size_to_append = s.size() + 1;
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char_data.resize(old_size + size_to_append);
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memcpy(&char_data[old_size], s.c_str(), size_to_append);
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offsets.push_back((offsets.size() == 0 ? 0 : offsets.back()) + size_to_append);
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}
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void insertDefault()
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{
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char_data.push_back(0);
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offsets.push_back(offsets.size() == 0 ? 1 : (offsets.back() + 1));
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}
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int compareAt(size_t n, size_t m, const IColumn & rhs_) const
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{
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const ColumnString & rhs = static_cast<const ColumnString &>(rhs_);
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size_t lhs_size = sizeAt(n);
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size_t rhs_size = rhs.sizeAt(m);
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size_t min_size = std::min(lhs_size, rhs_size);
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if (size_t res = memcmp(&char_data[offsetAt(n)], &rhs.char_data[rhs.offsetAt(m)], min_size))
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return res;
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return lhs_size < rhs_size
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? -1
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: (lhs_size == rhs_size
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? 0
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: 1);
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return 0;
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}
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};
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}
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