| // 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 priotization 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{} |
| } |