// Copyright 2019 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.

//go:build !unix

package bio

func (r *Reader) sliceOS(length uint64) ([]byte, bool) {
	return nil, false

//	OpenBSD   unlimited
var mmapLimit int32 = 1<<31 - 1

func init() {
	// Linux is the only practically concerning OS.
	if runtime.GOOS == "linux" {
		mmapLimit = 30000
	}
}

func (r *Reader) sliceOS(length uint64) ([]byte, bool) {
	// For small slices, don't bother with the overhead of a
	// mapping, especially since we have no way to unmap it.
	const threshold = 16 << 10
	if length < threshold {
		return nil, false