/
probability.go
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/
probability.go
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// Copyright 2017-2019 Lei Ni (nilei81@gmail.com)
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package random
const (
oneMillion uint64 = 100 * 10000
)
// Probability is used to represent a random probability.
type Probability struct {
p uint64
r uint64
}
// NewProbability returns a new Probability instance, the probability is
// is expressed a outOfMillion / one million, e.g. NewProbability(1) means
// there is 1 out of 1 million chance.
func NewProbability(outOfMillion uint64) *Probability {
return &Probability{
p: outOfMillion,
r: LockGuardedRand.Uint64() % oneMillion,
}
}
// Hit returns a boolean value indicating whether the random event is within
// the specified random range.
func (p *Probability) Hit() bool {
return p.p > p.r
}
// Missed returns a boolean value indicating whether the random event is not
// within the specified random range.
func (p *Probability) Missed() bool {
return !p.Hit()
}