var flateWriterPool sync.Pool

func newFlateWriter(w io.Writer) io.WriteCloser {
	fw, ok := flateWriterPool.Get().(*flate.Writer)
	if ok {
		fw.Reset(w)
	} else {
		fw, _ = flate.NewWriter(w, 5)
	}
	return &pooledFlateWriter{fw: fw}
}

type pooledFlateWriter struct {
	mu sync.Mutex // guards Close and Write
	fw *flate.Writer
}

func (w *pooledFlateWriter) Write(p []byte) (n int, err error) {
	w.mu.Lock()

		Name: "lorem.txt",
		Mode: 0600,
		Size: int64(len(inp)),
	})
	if err != nil {
		f.Fatalf("failed to create writer: %s", err)
	}
	_, err = w.Write(inp)
	if err != nil {
		f.Fatalf("failed to write file to archive: %s", err)
	}
	if err := w.Close(); err != nil {
		f.Fatalf("failed to write archive: %s", err)
	}
	f.Add(b.Bytes())

	f.Fuzz(func(t *testing.T, b []byte) {
		r := NewReader(bytes.NewReader(b))

	return abs, nil
}

// WriteTo implements the [io.WriterTo] interface.
func (r *Reader) WriteTo(w io.Writer) (n int64, err error) {
	r.prevRune = -1
	if r.i >= int64(len(r.s)) {
		return 0, nil
	}
	b := r.s[r.i:]
	m, err := w.Write(b)
	if m > len(b) {
		panic("bytes.Reader.WriteTo: invalid Write count")
	}
	r.i += int64(m)
	n = int64(m)
	if m != len(b) && err == nil {
		err = io.ErrShortWrite
	}

pkg archive/tar, method (*Writer) AddFS(fs.FS) error #58000
pkg archive/zip, method (*Writer) AddFS(fs.FS) error #54898
pkg cmp, func Or[$0 comparable](...$0) $0 #60204
pkg crypto/x509, func OIDFromInts([]uint64) (OID, error) #60665
pkg crypto/x509, method (*CertPool) AddCertWithConstraint(*Certificate, func([]*Certificate) error) #57178
pkg crypto/x509, method (OID) Equal(OID) bool #60665
pkg crypto/x509, method (OID) EqualASN1OID(asn1.ObjectIdentifier) bool #60665

func TestReaderCopyNothing(t *testing.T) {
	type nErr struct {
		n   int64
		err error
	}
	type justReader struct {
		io.Reader
	}
	type justWriter struct {
		io.Writer
	}
	discard := justWriter{io.Discard} // hide ReadFrom

	var with, withOut nErr
	with.n, with.err = io.Copy(discard, NewReader(nil))
	withOut.n, withOut.err = io.Copy(discard, justReader{NewReader(nil)})

### Iterators

The new [`iter` package](/pkg/iter/) provides the basic definitions for

// Copyright 2011 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 main

import (
	"fmt"
	"go/ast"
	"go/printer"
	"go/token"
	"os"
	"path/filepath"
	"strings"
)

// godefs returns the output for -godefs mode.
func (p *Package) godefs(f *File, args []string) string {
	var buf strings.Builder

Errors returned by [driver.Valuer] implementations are now wrapped for
improved error handling during operations like [DB.Query], [DB.Exec],

	"fmt"
	"log"
	"os"
	"strconv"
	"strings"

	"cmd/internal/objfile"
)

func printUsage(w *os.File) {
	fmt.Fprintf(w, "usage: addr2line binary\n")
	fmt.Fprintf(w, "reads addresses from standard input and writes two lines for each:\n")
	fmt.Fprintf(w, "\tfunction name\n")
	fmt.Fprintf(w, "\tfile:line\n")
}

func usage() {
	printUsage(os.Stderr)
	os.Exit(2)
}

func main() {
	log.SetFlags(0)