github.com/m3db/m3@v1.5.1-0.20231129193456-75a402aa583b/src/m3ninx/index/segment/mem/bytes_slice_iterator.go (about)

     1  // Copyright (c) 2018 Uber Technologies, Inc.
     2  //
     3  // Permission is hereby granted, free of charge, to any person obtaining a copy
     4  // of this software and associated documentation files (the "Software"), to deal
     5  // in the Software without restriction, including without limitation the rights
     6  // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
     7  // copies of the Software, and to permit persons to whom the Software is
     8  // furnished to do so, subject to the following conditions:
     9  //
    10  // The above copyright notice and this permission notice shall be included in
    11  // all copies or substantial portions of the Software.
    12  //
    13  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    14  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    15  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    16  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    17  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    18  // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
    19  // THE SOFTWARE.
    20  
    21  package mem
    22  
    23  import (
    24  	"bytes"
    25  	"sort"
    26  
    27  	sgmt "github.com/m3db/m3/src/m3ninx/index/segment"
    28  )
    29  
    30  type bytesSliceIter struct {
    31  	err  error
    32  	done bool
    33  
    34  	currentIdx   int
    35  	current      []byte
    36  	backingSlice [][]byte
    37  	opts         Options
    38  }
    39  
    40  var _ sgmt.FieldsIterator = &bytesSliceIter{}
    41  
    42  func newBytesSliceIter(slice [][]byte, opts Options) *bytesSliceIter {
    43  	sortSliceOfByteSlices(slice)
    44  	return &bytesSliceIter{
    45  		currentIdx:   -1,
    46  		backingSlice: slice,
    47  		opts:         opts,
    48  	}
    49  }
    50  
    51  func (b *bytesSliceIter) Empty() bool {
    52  	return len(b.backingSlice) == 0
    53  }
    54  
    55  func (b *bytesSliceIter) Next() bool {
    56  	if b.done || b.err != nil {
    57  		return false
    58  	}
    59  	b.currentIdx++
    60  	if b.currentIdx >= len(b.backingSlice) {
    61  		b.done = true
    62  		return false
    63  	}
    64  	b.current = b.backingSlice[b.currentIdx]
    65  	return true
    66  }
    67  
    68  func (b *bytesSliceIter) Current() []byte {
    69  	return b.current
    70  }
    71  
    72  func (b *bytesSliceIter) Err() error {
    73  	return nil
    74  }
    75  
    76  func (b *bytesSliceIter) Len() int {
    77  	return len(b.backingSlice)
    78  }
    79  
    80  func (b *bytesSliceIter) Close() error {
    81  	b.current = nil
    82  	b.opts.BytesSliceArrayPool().Put(b.backingSlice)
    83  	return nil
    84  }
    85  
    86  func sortSliceOfByteSlices(b [][]byte) {
    87  	sort.Slice(b, func(i, j int) bool {
    88  		return bytes.Compare(b[i], b[j]) < 0
    89  	})
    90  }