github.com/hdt3213/godis@v1.2.9/datastruct/sortedset/border.go (about)

     1  package sortedset
     2  
     3  import (
     4  	"errors"
     5  	"strconv"
     6  )
     7  
     8  /*
     9   * ScoreBorder is a struct represents `min` `max` parameter of redis command `ZRANGEBYSCORE`
    10   * can accept:
    11   *   int or float value, such as 2.718, 2, -2.718, -2 ...
    12   *   exclusive int or float value, such as (2.718, (2, (-2.718, (-2 ...
    13   *   infinity: +inf, -inf， inf(same as +inf)
    14   */
    15  
    16  const (
    17  	negativeInf int8 = -1
    18  	positiveInf int8 = 1
    19  )
    20  
    21  // ScoreBorder represents range of a float value, including: <, <=, >, >=, +inf, -inf
    22  type ScoreBorder struct {
    23  	Inf     int8
    24  	Value   float64
    25  	Exclude bool
    26  }
    27  
    28  // if max.greater(score) then the score is within the upper border
    29  // do not use min.greater()
    30  func (border *ScoreBorder) greater(value float64) bool {
    31  	if border.Inf == negativeInf {
    32  		return false
    33  	} else if border.Inf == positiveInf {
    34  		return true
    35  	}
    36  	if border.Exclude {
    37  		return border.Value > value
    38  	}
    39  	return border.Value >= value
    40  }
    41  
    42  func (border *ScoreBorder) less(value float64) bool {
    43  	if border.Inf == negativeInf {
    44  		return true
    45  	} else if border.Inf == positiveInf {
    46  		return false
    47  	}
    48  	if border.Exclude {
    49  		return border.Value < value
    50  	}
    51  	return border.Value <= value
    52  }
    53  
    54  var positiveInfBorder = &ScoreBorder{
    55  	Inf: positiveInf,
    56  }
    57  
    58  var negativeInfBorder = &ScoreBorder{
    59  	Inf: negativeInf,
    60  }
    61  
    62  // ParseScoreBorder creates ScoreBorder from redis arguments
    63  func ParseScoreBorder(s string) (*ScoreBorder, error) {
    64  	if s == "inf" || s == "+inf" {
    65  		return positiveInfBorder, nil
    66  	}
    67  	if s == "-inf" {
    68  		return negativeInfBorder, nil
    69  	}
    70  	if s[0] == '(' {
    71  		value, err := strconv.ParseFloat(s[1:], 64)
    72  		if err != nil {
    73  			return nil, errors.New("ERR min or max is not a float")
    74  		}
    75  		return &ScoreBorder{
    76  			Inf:     0,
    77  			Value:   value,
    78  			Exclude: true,
    79  		}, nil
    80  	}
    81  	value, err := strconv.ParseFloat(s, 64)
    82  	if err != nil {
    83  		return nil, errors.New("ERR min or max is not a float")
    84  	}
    85  	return &ScoreBorder{
    86  		Inf:     0,
    87  		Value:   value,
    88  		Exclude: false,
    89  	}, nil
    90  }