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79 lines
2.8 KiB
C++
79 lines
2.8 KiB
C++
#pragma once
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#include <Core/ColumnWithTypeAndName.h>
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#include <Core/ColumnsWithTypeAndName.h>
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#include <Core/Field.h>
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#include <Common/PODArray.h>
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namespace DB
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{
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/// Expand data by mask. After expanding data will satisfy the following: if we filter data
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/// by given mask, we get initial data. In places where mask[i] = 0 we insert default value.
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/// If inverted is true, we will work with inverted mask. This function is used in implementations of
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/// expand() method in IColumn interface.
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template <typename T>
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void expandDataByMask(PaddedPODArray<T> & data, const PaddedPODArray<UInt8> & mask, bool inverted, T default_value = T());
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struct MaskInfo
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{
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bool has_ones;
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bool has_zeros;
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};
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/// The next functions are used to extract UInt8 mask from a column,
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/// filtered by some condition (mask). We will use value from a column
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/// only when value in condition is 1. Column should satisfy the
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/// condition: sum(mask) = column.size() or mask.size() = column.size().
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/// You can set flag 'inverted' to use inverted values
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/// from a column. You can also determine value that will be used when
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/// column value is Null (argument null_value).
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MaskInfo extractMask(
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PaddedPODArray<UInt8> & mask,
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const ColumnPtr & column,
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UInt8 null_value = 0);
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MaskInfo extractInvertedMask(
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PaddedPODArray<UInt8> & mask,
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const ColumnPtr & column,
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UInt8 null_value = 0);
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/// The same as extractMask, but fills
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/// nulls so that nulls[i] = 1 when column[i] = Null.
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MaskInfo extractMask(
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PaddedPODArray<UInt8> & mask,
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const ColumnPtr & column,
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PaddedPODArray<UInt8> * nulls,
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UInt8 null_value = 0);
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MaskInfo extractInvertedMask(
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PaddedPODArray<UInt8> & mask,
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const ColumnPtr & column,
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PaddedPODArray<UInt8> * nulls,
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UInt8 null_value = 0);
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/// Inplace inversion.
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void inverseMask(PaddedPODArray<UInt8> & mask, MaskInfo & mask_info);
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/// If given column is lazy executed argument (ColumnFunction with isShortCircuitArgument() = true),
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/// filter it by mask and then reduce. If inverted is true, we will work with inverted mask.
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/// mask_info is used for for optimization in cases when we have all zeros or all ones in mask, so
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/// in general case this info is not used and we can skip it.
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void maskedExecute(
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ColumnWithTypeAndName & column,
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const PaddedPODArray<UInt8> & mask,
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const MaskInfo & mask_info = {true, true});
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/// If given column is lazy executed argument, reduce it. If empty is true,
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/// create an empty column with the execution result type.
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void executeColumnIfNeeded(ColumnWithTypeAndName & column, bool empty = false);
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/// Check if arguments contain lazy executed argument. If contain, return index of the last one,
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/// otherwise return -1.
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int checkShortCircuitArguments(const ColumnsWithTypeAndName & arguments);
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void copyMask(const PaddedPODArray<UInt8> & from, PaddedPODArray<UInt8> & to);
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}
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