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https://github.com/ClickHouse/ClickHouse.git
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481 lines
10 KiB
C++
481 lines
10 KiB
C++
#pragma once
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#include <DB/IO/WriteHelpers.h>
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#include <DB/IO/ReadHelpers.h>
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#include <DB/Columns/ColumnVector.h>
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#include <DB/Columns/ColumnString.h>
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#include <DB/AggregateFunctions/IUnaryAggregateFunction.h>
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namespace DB
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{
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/** Агрегатные функции, запоминающие одно какое-либо переданное значение.
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* Например, min, max, any, anyLast.
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*/
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/// Для числовых значений.
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template <typename T>
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struct SingleValueDataFixed
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{
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typedef SingleValueDataFixed<T> Self;
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bool has_value = false; /// Надо запомнить, было ли передано хотя бы одно значение. Это нужно для AggregateFunctionIf.
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T value;
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bool has() const
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{
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return has_value;
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}
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void insertResultInto(IColumn & to) const
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{
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if (has())
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static_cast<ColumnVector<T> &>(to).getData().push_back(value);
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else
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static_cast<ColumnVector<T> &>(to).insertDefault();
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}
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void write(WriteBuffer & buf, const IDataType & data_type) const
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{
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writeBinary(has(), buf);
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if (has())
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writeBinary(value, buf);
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}
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void read(ReadBuffer & buf, const IDataType & data_type)
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{
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readBinary(has_value, buf);
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if (has())
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readBinary(value, buf);
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}
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void change(const IColumn & column, size_t row_num)
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{
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has_value = true;
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value = static_cast<const ColumnVector<T> &>(column).getData()[row_num];
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}
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void change(const Self & to)
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{
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has_value = true;
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value = to.value;
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}
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void changeFirstTime(const IColumn & column, size_t row_num)
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{
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if (!has())
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change(column, row_num);
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}
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void changeFirstTime(const Self & to)
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{
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if (!has())
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change(to);
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}
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void changeIfLess(const IColumn & column, size_t row_num)
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{
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if (!has() || static_cast<const ColumnVector<T> &>(column).getData()[row_num] < value)
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change(column, row_num);
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}
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void changeIfLess(const Self & to)
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{
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if (to.has() && (!has() || to.value < value))
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change(to);
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}
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void changeIfGreater(const IColumn & column, size_t row_num)
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{
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if (!has() || static_cast<const ColumnVector<T> &>(column).getData()[row_num] > value)
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change(column, row_num);
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}
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void changeIfGreater(const Self & to)
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{
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if (to.has() && (!has() || to.value > value))
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change(to);
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}
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};
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/** Для строк. Короткие строки хранятся в самой структуре, а длинные выделяются отдельно.
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* NOTE Могло бы подойти также для массивов чисел.
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*/
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struct __attribute__((__packed__)) SingleValueDataString
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{
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typedef SingleValueDataString Self;
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Int32 size = -1; /// -1 обозначает, что значения нет.
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static constexpr Int32 AUTOMATIC_STORAGE_SIZE = 64;
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static constexpr Int32 MAX_SMALL_STRING_SIZE = AUTOMATIC_STORAGE_SIZE - sizeof(size);
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union
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{
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char small_data[MAX_SMALL_STRING_SIZE]; /// Включая завершающий ноль.
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char * large_data;
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};
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~SingleValueDataString()
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{
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if (size > MAX_SMALL_STRING_SIZE)
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free(large_data);
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}
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bool has() const
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{
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return size >= 0;
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}
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const char * getData() const
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{
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return size <= MAX_SMALL_STRING_SIZE ? small_data : large_data;
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}
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StringRef getStringRef() const
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{
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return StringRef(getData(), size);
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}
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void insertResultInto(IColumn & to) const
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{
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if (has())
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static_cast<ColumnString &>(to).insertDataWithTerminatingZero(getData(), size);
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else
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static_cast<ColumnString &>(to).insertDefault();
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}
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void write(WriteBuffer & buf, const IDataType & data_type) const
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{
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writeBinary(size, buf);
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if (has())
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buf.write(getData(), size);
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}
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void read(ReadBuffer & buf, const IDataType & data_type)
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{
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Int32 rhs_size;
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readBinary(rhs_size, buf);
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if (rhs_size >= 0)
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{
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if (rhs_size <= MAX_SMALL_STRING_SIZE)
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{
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if (size > MAX_SMALL_STRING_SIZE)
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free(large_data);
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size = rhs_size;
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if (size > 0)
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buf.read(small_data, size);
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}
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else
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{
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if (size < rhs_size)
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{
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if (size > MAX_SMALL_STRING_SIZE)
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free(large_data);
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large_data = reinterpret_cast<char *>(malloc(rhs_size));
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}
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size = rhs_size;
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buf.read(large_data, size);
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}
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}
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else
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{
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if (size > MAX_SMALL_STRING_SIZE)
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free(large_data);
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size = rhs_size;
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}
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}
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void changeImpl(StringRef value)
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{
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Int32 value_size = value.size;
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if (value_size <= MAX_SMALL_STRING_SIZE)
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{
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if (size > MAX_SMALL_STRING_SIZE)
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free(large_data);
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size = value_size;
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if (size > 0)
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memcpy(small_data, value.data, size);
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}
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else
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{
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if (size < value_size)
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{
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if (size > MAX_SMALL_STRING_SIZE)
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free(large_data);
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large_data = reinterpret_cast<char *>(malloc(value.size));
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}
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size = value_size;
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memcpy(large_data, value.data, size);
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}
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}
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void change(const IColumn & column, size_t row_num)
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{
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changeImpl(static_cast<const ColumnString &>(column).getDataAtWithTerminatingZero(row_num));
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}
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void change(const Self & to)
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{
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changeImpl(to.getStringRef());
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}
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void changeFirstTime(const IColumn & column, size_t row_num)
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{
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if (!has())
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change(column, row_num);
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}
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void changeFirstTime(const Self & to)
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{
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if (!has())
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change(to);
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}
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void changeIfLess(const IColumn & column, size_t row_num)
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{
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if (!has() || static_cast<const ColumnString &>(column).getDataAtWithTerminatingZero(row_num) < getStringRef())
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change(column, row_num);
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}
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void changeIfLess(const Self & to)
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{
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if (to.has() && (!has() || to.getStringRef() < getStringRef()))
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change(to);
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}
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void changeIfGreater(const IColumn & column, size_t row_num)
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{
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if (!has() || static_cast<const ColumnString &>(column).getDataAtWithTerminatingZero(row_num) > getStringRef())
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change(column, row_num);
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}
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void changeIfGreater(const Self & to)
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{
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if (to.has() && (!has() || to.getStringRef() > getStringRef()))
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change(to);
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}
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};
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/// Для любых других типов значений.
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struct SingleValueDataGeneric
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{
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typedef SingleValueDataGeneric Self;
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Field value;
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bool has() const
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{
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return !value.isNull();
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}
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void insertResultInto(IColumn & to) const
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{
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if (has())
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to.insert(value);
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else
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to.insertDefault();
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}
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void write(WriteBuffer & buf, const IDataType & data_type) const
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{
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if (!value.isNull())
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{
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writeBinary(true, buf);
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data_type.serializeBinary(value, buf);
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}
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else
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writeBinary(false, buf);
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}
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void read(ReadBuffer & buf, const IDataType & data_type)
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{
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bool is_not_null;
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readBinary(is_not_null, buf);
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if (is_not_null)
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data_type.deserializeBinary(value, buf);
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}
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void change(const IColumn & column, size_t row_num)
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{
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column.get(row_num, value);
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}
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void change(const Self & to)
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{
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value = to.value;
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}
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void changeFirstTime(const IColumn & column, size_t row_num)
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{
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if (!has())
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change(column, row_num);
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}
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void changeFirstTime(const Self & to)
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{
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if (!has())
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change(to);
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}
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void changeIfLess(const IColumn & column, size_t row_num)
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{
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if (!has())
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change(column, row_num);
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else
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{
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Field new_value;
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column.get(row_num, new_value);
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if (new_value < value)
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value = new_value;
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}
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}
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void changeIfLess(const Self & to)
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{
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if (to.has() && (!has() || to.value < value))
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change(to);
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}
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void changeIfGreater(const IColumn & column, size_t row_num)
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{
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if (!has())
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change(column, row_num);
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else
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{
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Field new_value;
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column.get(row_num, new_value);
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if (new_value > value)
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value = new_value;
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}
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}
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void changeIfGreater(const Self & to)
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{
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if (to.has() && (!has() || to.value > value))
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change(to);
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}
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};
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/** То, чем отличаются друг от другая агрегатные функции min, max, any, anyLast
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* (условием, при котором сохранённое значение заменяется на новое,
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* а также, конечно, именем).
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*/
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template <typename Data>
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struct AggregateFunctionMinData : Data
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{
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typedef AggregateFunctionMinData<Data> Self;
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void changeIfBetter(const IColumn & column, size_t row_num) { this->changeIfLess(column, row_num); }
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void changeIfBetter(const Self & to) { this->changeIfLess(to); }
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static const char * name() { return "min"; }
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};
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template <typename Data>
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struct AggregateFunctionMaxData : Data
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{
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typedef AggregateFunctionMaxData<Data> Self;
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void changeIfBetter(const IColumn & column, size_t row_num) { this->changeIfGreater(column, row_num); }
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void changeIfBetter(const Self & to) { this->changeIfGreater(to); }
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static const char * name() { return "max"; }
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};
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template <typename Data>
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struct AggregateFunctionAnyData : Data
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{
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typedef AggregateFunctionAnyData<Data> Self;
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void changeIfBetter(const IColumn & column, size_t row_num) { this->changeFirstTime(column, row_num); }
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void changeIfBetter(const Self & to) { this->changeFirstTime(to); }
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static const char * name() { return "any"; }
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};
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template <typename Data>
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struct AggregateFunctionAnyLastData : Data
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{
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typedef AggregateFunctionAnyLastData<Data> Self;
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void changeIfBetter(const IColumn & column, size_t row_num) { this->change(column, row_num); }
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void changeIfBetter(const Self & to) { this->change(to); }
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static const char * name() { return "anyLast"; }
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};
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template <typename Data>
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class AggregateFunctionsSingleValue final : public IUnaryAggregateFunction<Data, AggregateFunctionsSingleValue<Data> >
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{
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private:
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DataTypePtr type;
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public:
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String getName() const { return Data::name(); }
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DataTypePtr getReturnType() const
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{
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return type;
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}
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void setArgument(const DataTypePtr & argument)
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{
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type = argument;
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}
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void addOne(AggregateDataPtr place, const IColumn & column, size_t row_num) const
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{
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this->data(place).changeIfBetter(column, row_num);
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}
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void merge(AggregateDataPtr place, ConstAggregateDataPtr rhs) const
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{
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this->data(place).changeIfBetter(this->data(rhs));
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}
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void serialize(ConstAggregateDataPtr place, WriteBuffer & buf) const
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{
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this->data(place).write(buf, *type.get());
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}
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void deserializeMerge(AggregateDataPtr place, ReadBuffer & buf) const
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{
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Data rhs; /// Для строчек не очень оптимально, так как может делаться одна лишняя аллокация.
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rhs.read(buf, *type.get());
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this->data(place).changeIfBetter(rhs);
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}
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void insertResultInto(ConstAggregateDataPtr place, IColumn & to) const
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{
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this->data(place).insertResultInto(to);
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}
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};
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}
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