| // Copyright 2021 The Go Authors. All rights reserved. | |
| // Use of this source code is governed by a BSD-style | |
| // license that can be found in the LICENSE file. | |
| package fuzz | |
| // queue holds a growable sequence of inputs for fuzzing and minimization. | |
| // | |
| // For now, this is a simple ring buffer | |
| // (https://en.wikipedia.org/wiki/Circular_buffer). | |
| // | |
| // TODO(golang.org/issue/46224): use a prioritization algorithm based on input | |
| // size, previous duration, coverage, and any other metrics that seem useful. | |
| type queue struct { | |
| // elems holds a ring buffer. | |
| // The queue is empty when begin = end. | |
| // The queue is full (until grow is called) when end = begin + N - 1 (mod N) | |
| // where N = cap(elems). | |
| elems []any | |
| head, len int | |
| } | |
| func (q *queue) cap() int { | |
| return len(q.elems) | |
| } | |
| func (q *queue) grow() { | |
| oldCap := q.cap() | |
| newCap := oldCap * 2 | |
| if newCap == 0 { | |
| newCap = 8 | |
| } | |
| newElems := make([]any, newCap) | |
| oldLen := q.len | |
| for i := 0; i < oldLen; i++ { | |
| newElems[i] = q.elems[(q.head+i)%oldCap] | |
| } | |
| q.elems = newElems | |
| q.head = 0 | |
| } | |
| func (q *queue) enqueue(e any) { | |
| if q.len+1 > q.cap() { | |
| q.grow() | |
| } | |
| i := (q.head + q.len) % q.cap() | |
| q.elems[i] = e | |
| q.len++ | |
| } | |
| func (q *queue) dequeue() (any, bool) { | |
| if q.len == 0 { | |
| return nil, false | |
| } | |
| e := q.elems[q.head] | |
| q.elems[q.head] = nil | |
| q.head = (q.head + 1) % q.cap() | |
| q.len-- | |
| return e, true | |
| } | |
| func (q *queue) peek() (any, bool) { | |
| if q.len == 0 { | |
| return nil, false | |
| } | |
| return q.elems[q.head], true | |
| } | |
| func (q *queue) clear() { | |
| *q = queue{} | |
| } | |