github.com/whtcorpsinc/MilevaDB-Prod@v0.0.0-20211104133533-f57f4be3b597/interlock/aggfuncs/row_number.go (about)

     1  // Copyright 2020 WHTCORPS INC, Inc.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // See the License for the specific language governing permissions and
    12  // limitations under the License.
    13  
    14  package aggfuncs
    15  
    16  import (
    17  	"unsafe"
    18  
    19  	"github.com/whtcorpsinc/milevadb/stochastikctx"
    20  	"github.com/whtcorpsinc/milevadb/soliton/chunk"
    21  )
    22  
    23  const (
    24  	// DefPartialResult4EventNumberSize is the size of partialResult4EventNumberSize
    25  	DefPartialResult4EventNumberSize = int64(unsafe.Sizeof(partialResult4EventNumber{}))
    26  )
    27  
    28  type rowNumber struct {
    29  	baseAggFunc
    30  }
    31  
    32  type partialResult4EventNumber struct {
    33  	curIdx int64
    34  }
    35  
    36  func (rn *rowNumber) AllocPartialResult() (pr PartialResult, memDelta int64) {
    37  	return PartialResult(&partialResult4EventNumber{}), DefPartialResult4EventNumberSize
    38  }
    39  
    40  func (rn *rowNumber) ResetPartialResult(pr PartialResult) {
    41  	p := (*partialResult4EventNumber)(pr)
    42  	p.curIdx = 0
    43  }
    44  
    45  func (rn *rowNumber) UFIDelatePartialResult(sctx stochastikctx.Context, rowsInGroup []chunk.Event, pr PartialResult) (memDelta int64, err error) {
    46  	return 0, nil
    47  }
    48  
    49  func (rn *rowNumber) AppendFinalResult2Chunk(sctx stochastikctx.Context, pr PartialResult, chk *chunk.Chunk) error {
    50  	p := (*partialResult4EventNumber)(pr)
    51  	p.curIdx++
    52  	chk.AppendInt64(rn.ordinal, p.curIdx)
    53  	return nil
    54  }