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141 lines
3.3 KiB
C++
141 lines
3.3 KiB
C++
#pragma once
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#include <string.h> // memcpy
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#include <DB/Common/PODArray.h>
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#include <DB/Columns/IColumn.h>
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namespace DB
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{
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/** A column of values of "fixed-length string" type.
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* If you insert a smaller string, it will be padded with zero bytes.
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*/
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class ColumnFixedString final : public IColumn
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{
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public:
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using Chars_t = PaddedPODArray<UInt8>;
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private:
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/// Bytes of rows, laid in succession. The strings are stored without a trailing zero byte.
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/** NOTE It is required that the offset and type of chars in the object be the same as that of `data in ColumnUInt8`.
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* Used in `packFixed` function (AggregationCommon.h)
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*/
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Chars_t chars;
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/// The size of the rows.
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const size_t n;
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template <bool positive>
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struct less;
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public:
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/** Create an empty column of strings of fixed-length `n` */
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ColumnFixedString(size_t n_) : n(n_) {}
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std::string getName() const override { return "ColumnFixedString"; }
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ColumnPtr cloneResized(size_t size) const override;
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size_t size() const override
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{
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return chars.size() / n;
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}
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size_t sizeOfField() const override
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{
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return n;
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}
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bool isFixed() const override
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{
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return true;
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}
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size_t byteSize() const override
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{
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return chars.size() + sizeof(n);
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}
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size_t allocatedSize() const override
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{
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return chars.allocated_size() + sizeof(n);
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}
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Field operator[](size_t index) const override
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{
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return String(reinterpret_cast<const char *>(&chars[n * index]), n);
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}
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void get(size_t index, Field & res) const override
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{
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res.assignString(reinterpret_cast<const char *>(&chars[n * index]), n);
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}
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StringRef getDataAt(size_t index) const override
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{
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return StringRef(&chars[n * index], n);
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}
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void insert(const Field & x) override;
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void insertFrom(const IColumn & src_, size_t index) override;
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void insertData(const char * pos, size_t length) override;
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void insertDefault() override
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{
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chars.resize_fill(chars.size() + n);
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}
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void popBack(size_t elems) override
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{
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chars.resize_assume_reserved(chars.size() - n * elems);
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}
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StringRef serializeValueIntoArena(size_t index, Arena & arena, char const *& begin) const override;
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const char * deserializeAndInsertFromArena(const char * pos) override;
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void updateHashWithValue(size_t index, SipHash & hash) const override;
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int compareAt(size_t p1, size_t p2, const IColumn & rhs_, int nan_direction_hint) const override
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{
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const ColumnFixedString & rhs = static_cast<const ColumnFixedString &>(rhs_);
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return memcmp(&chars[p1 * n], &rhs.chars[p2 * n], n);
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}
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void getPermutation(bool reverse, size_t limit, Permutation & res) const override;
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void insertRangeFrom(const IColumn & src, size_t start, size_t length) override;
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ColumnPtr filter(const IColumn::Filter & filt, ssize_t result_size_hint) const override;
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ColumnPtr permute(const Permutation & perm, size_t limit) const override;
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ColumnPtr replicate(const Offsets_t & offsets) const override;
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Columns scatter(ColumnIndex num_columns, const Selector & selector) const override
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{
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return scatterImpl<ColumnFixedString>(num_columns, selector);
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}
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void reserve(size_t size) override
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{
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chars.reserve(n * size);
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};
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void getExtremes(Field & min, Field & max) const override;
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/// Specialized part of interface, not from IColumn.
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Chars_t & getChars() { return chars; }
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const Chars_t & getChars() const { return chars; }
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size_t getN() const { return n; }
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};
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}
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