github.com/m3db/m3@v1.5.0/src/x/time/range_iter.go (about)

     1  // Copyright (c) 2016 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
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     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 time
    22  
    23  import "container/list"
    24  
    25  // RangeIter iterates over a collection of time ranges.
    26  type RangeIter struct {
    27  	ranges *list.List
    28  	cur    *list.Element
    29  	eof    bool
    30  }
    31  
    32  func newRangeIter(ranges *list.List) *RangeIter {
    33  	return &RangeIter{ranges: ranges}
    34  }
    35  
    36  // Next moves to the next item.
    37  func (it *RangeIter) Next() bool {
    38  	if it.ranges == nil {
    39  		return false
    40  	}
    41  	if it.eof {
    42  		return false
    43  	}
    44  	if it.cur == nil {
    45  		it.cur = it.ranges.Front()
    46  	} else {
    47  		it.cur = it.cur.Next()
    48  	}
    49  	it.eof = it.cur == nil
    50  	return !it.eof
    51  }
    52  
    53  // Value returns the current time range.
    54  func (it *RangeIter) Value() Range {
    55  	if it.cur == nil {
    56  		return Range{}
    57  	}
    58  	return it.cur.Value.(Range)
    59  }