vendor: update all dependencies to latest versions

vendor/cloud.google.com/go/pubsub/internal/distribution/distribution.go

@@ -0,0 +1,70 @@
+// Copyright 2017 Google Inc. All Rights Reserved.
+//
+// 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 distribution
+
+import (
+	"log"
+	"math"
+	"sort"
+	"sync/atomic"
+)
+
+// D is a distribution. Methods of D can be called concurrently by multiple
+// goroutines.
+type D struct {
+	buckets []uint64
+}
+
+// New creates a new distribution capable of holding values from 0 to n-1.
+func New(n int) *D {
+	return &D{
+		buckets: make([]uint64, n),
+	}
+}
+
+// Record records value v to the distribution.
+// To help with distributions with long tails, if v is larger than the maximum value,
+// Record records the maximum value instead.
+// If v is negative, Record panics.
+func (d *D) Record(v int) {
+	if v < 0 {
+		log.Panicf("Record: value out of range: %d", v)
+	} else if v >= len(d.buckets) {
+		v = len(d.buckets) - 1
+	}
+	atomic.AddUint64(&d.buckets[v], 1)
+}
+
+// Percentile computes the p-th percentile of the distribution where
+// p is between 0 and 1.
+func (d *D) Percentile(p float64) int {
+	// NOTE: This implementation uses the nearest-rank method.
+	// https://en.wikipedia.org/wiki/Percentile#The_nearest-rank_method
+
+	if p < 0 || p > 1 {
+		log.Panicf("Percentile: percentile out of range: %f", p)
+	}
+
+	bucketSums := make([]uint64, len(d.buckets))
+	var sum uint64
+	for i := range bucketSums {
+		sum += atomic.LoadUint64(&d.buckets[i])
+		bucketSums[i] = sum
+	}
+
+	total := bucketSums[len(bucketSums)-1]
+	target := uint64(math.Ceil(float64(total) * p))
+	return sort.Search(len(bucketSums), func(i int) bool { return bucketSums[i] >= target })
+}