//
// [underlying type]: https://go.dev/ref/spec#Underlying_types.
func (a *Alias) Underlying() Type { return unalias(a).Underlying() }

// Origin returns the generic Alias type of which a is an instance.
// If a is not an instance of a generic alias, Origin returns a.
func (a *Alias) Origin() *Alias { return a.orig }

// TypeParams returns the type parameters of the alias type a, or nil.

//
// [underlying type]: https://go.dev/ref/spec#Underlying_types.
func (a *Alias) Underlying() Type { return unalias(a).Underlying() }

// Origin returns the generic Alias type of which a is an instance.
// If a is not an instance of a generic alias, Origin returns a.
func (a *Alias) Origin() *Alias { return a.orig }

// TypeParams returns the type parameters of the alias type a, or nil.

// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

//go:build unix

package syscall

import (
	"sync/atomic"
)

// origRlimitNofile, if non-nil, is the original soft RLIMIT_NOFILE.
var origRlimitNofile atomic.Pointer[Rlimit]

// Some systems set an artificially low soft limit on open file count, for compatibility
// with code that uses select and its hard-coded maximum file descriptor

// origin returns the original uninstantiated symbol for obj.
func origin(obj types.Object) types.Object {
	switch obj := obj.(type) {
	case *types.Var:
		return obj.Origin()
	case *types.Func:
		return obj.Origin()
	case *types.TypeName:
		if named, ok := obj.Type().(*types.Named); ok { // (don't unalias)
			return named.Origin().Obj()
		}
	}
	return obj
}

// It does not change the underlying hash state.
func (s *asmState) Sum(b []byte) []byte {
	if s.state != spongeAbsorbing {
		panic("sha3: Sum after Read")
	}

	// Copy the state to preserve the original.
	a := s.a

	// Hash the buffer. Note that we don't clear it because we
	// aren't updating the state.
	switch s.function {
	case sha3_224, sha3_256, sha3_384, sha3_512:
		klmd(s.function, &a, nil, s.buf)

	z := NewWriter(buf)
	msg := []byte("hello world")
	z.Write(msg)
	z.Close()
	z.Reset(buf2)
	z.Write(msg)
	z.Close()
	if buf.String() != buf2.String() {
		t.Errorf("buf2 %q != original buf of %q", buf2.String(), buf.String())
	}
}

type limitedWriter struct {
	N int
}

func (l *limitedWriter) Write(p []byte) (n int, err error) {
	if n := l.N; n < len(p) {
		l.N = 0

		after[p.ID] = []*Block{b}
		for {
			nextIdx := idToIdx[b.ID] + 1
			if nextIdx >= len(f.Blocks) { // reached end of function (maybe impossible?)
				break
			}
			nextb := f.Blocks[nextIdx]
			if nextb == p { // original loop predecessor is next
				break
			}
			if loopnest.b2l[nextb.ID] == loop {
				after[p.ID] = append(after[p.ID], nextb)
			}
			b = nextb
		}

	// underlying file descriptor with reference counting.
	RefCountPtr *int32

	// RefCount is the reference count of Sysfd. When a copy of an FD is made,
	// it points to the reference count of the original FD instance.
	RefCount int32

	// Cache for the file type, lazily initialized when Seek is called.
	Filetype uint32

	// If the file represents a directory, this field contains the current

// source position information (e.g. file and line). Note that we don't
// include function name as part of the sorting criteria, the thinking
// being that is better to provide things in the original source order.
func (p *pstate) sortUnits(units []extcu) {
	slices.SortFunc(units, func(ui, uj extcu) int {
		ifile := p.funcs[ui.fnfid].file
		jfile := p.funcs[uj.fnfid].file

func SortFunc[S ~[]E, E any](x S, cmp func(a, b E) int) {
	n := len(x)
	pdqsortCmpFunc(x, 0, n, bits.Len(uint(n)), cmp)
}

// SortStableFunc sorts the slice x while keeping the original order of equal
// elements, using cmp to compare elements in the same way as [SortFunc].
func SortStableFunc[S ~[]E, E any](x S, cmp func(a, b E) int) {
	stableCmpFunc(x, len(x), cmp)
}