github.com/m3db/m3@v1.5.0/src/m3ninx/index/segment/builder/terms_iter.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 builder
    22  
    23  import (
    24  	"github.com/m3db/m3/src/m3ninx/index/segment"
    25  	"github.com/m3db/m3/src/m3ninx/postings"
    26  )
    27  
    28  type termsIter struct {
    29  	err  error
    30  	done bool
    31  
    32  	currentIdx int
    33  	current    termElem
    34  	terms      []termElem
    35  }
    36  
    37  var _ segment.TermsIterator = &termsIter{}
    38  
    39  func newTermsIter(
    40  	orderedTerms []termElem,
    41  ) *termsIter {
    42  	return &termsIter{
    43  		currentIdx: -1,
    44  		terms:      orderedTerms,
    45  	}
    46  }
    47  
    48  func (b *termsIter) Empty() bool {
    49  	return b.Len() == 0
    50  }
    51  
    52  func (b *termsIter) Next() bool {
    53  	if b.done || b.err != nil {
    54  		return false
    55  	}
    56  	b.currentIdx++
    57  	if b.currentIdx >= len(b.terms) {
    58  		b.done = true
    59  		return false
    60  	}
    61  	b.current = b.terms[b.currentIdx]
    62  	return true
    63  }
    64  
    65  func (b *termsIter) Current() ([]byte, postings.List) {
    66  	return b.current.term, b.current.postings
    67  }
    68  
    69  func (b *termsIter) Err() error {
    70  	return nil
    71  }
    72  
    73  func (b *termsIter) Len() int {
    74  	return len(b.terms)
    75  }
    76  
    77  func (b *termsIter) Close() error {
    78  	b.current = termElem{}
    79  	b.terms = nil
    80  	return nil
    81  }