72 lines
1.5 KiB
Go
72 lines
1.5 KiB
Go
|
// 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{}
|
||
|
|
}
|