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main.go
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main.go
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package main
import (
"bufio"
"errors"
"flag"
"fmt"
"io"
"io/ioutil"
"os"
"path/filepath"
"runtime"
"strconv"
"strings"
"sync"
"time"
"unicode"
"github.com/klauspost/compress/s2"
"github.com/klauspost/compress/s2/cmd/internal/readahead"
)
var (
faster = flag.Bool("faster", false, "Compress faster, but with a minor compression loss")
cpu = flag.Int("cpu", runtime.GOMAXPROCS(0), "Compress using this amount of threads")
blockSize = flag.String("blocksize", "4M", "Max block size. Examples: 64K, 256K, 1M, 4M. Must be power of two and <= 4MB")
safe = flag.Bool("safe", false, "Do not overwrite output files")
padding = flag.String("pad", "1", "Pad size to a multiple of this value, Examples: 500, 64K, 256K, 1M, 4M, etc")
stdout = flag.Bool("c", false, "Write all output to stdout. Multiple input files will be concatenated")
remove = flag.Bool("rm", false, "Delete source file(s) after successful compression")
quiet = flag.Bool("q", false, "Don't write any output to terminal, except errors")
bench = flag.Int("bench", 0, "Run benchmark n times. No output will be written")
help = flag.Bool("help", false, "Display help")
version = "(dev)"
date = "(unknown)"
)
func main() {
flag.Parse()
sz, err := toSize(*blockSize)
exitErr(err)
pad, err := toSize(*padding)
exitErr(err)
args := flag.Args()
if len(args) == 0 || *help {
_, _ = fmt.Fprintf(os.Stderr, "s2 compress v%v, built at %v.\n\n", version, date)
_, _ = fmt.Fprintln(os.Stderr, `Usage: s2c [options] file1 file2
Compresses all files supplied as input separately.
Output files are written as 'filename.ext.s2'.
By default output files will be overwritten.
Use - as the only file name to read from stdin and write to stdout.
Wildcards are accepted: testdir/*.txt will compress all files in testdir ending with .txt
Directories can be wildcards as well. testdir/*/*.txt will match testdir/subdir/b.txt
Options:`)
flag.PrintDefaults()
}
opts := []s2.WriterOption{s2.WriterBlockSize(int(sz)), s2.WriterConcurrency(*cpu), s2.WriterPadding(int(pad))}
if !*faster {
opts = append(opts, s2.WriterBetterCompression())
}
wr := s2.NewWriter(nil, opts...)
// No args, use stdin/stdout
if len(args) == 1 && args[0] == "-" {
wr.Reset(os.Stdout)
_, err := io.Copy(wr, os.Stdin)
exitErr(err)
exitErr(wr.Close())
return
}
var files []string
for _, pattern := range args {
found, err := filepath.Glob(pattern)
exitErr(err)
if len(found) == 0 {
exitErr(fmt.Errorf("unable to find file %v", pattern))
}
files = append(files, found...)
}
*quiet = *quiet || *stdout
allFiles := files
for i := 0; i < *bench; i++ {
files = append(files, allFiles...)
}
for _, filename := range files {
func() {
var closeOnce sync.Once
dstFilename := fmt.Sprintf("%s%s", filename, ".s2")
if *bench > 0 {
dstFilename = "(discarded)"
}
if !*quiet {
fmt.Println("Compressing", filename, "->", dstFilename)
}
// Input file.
file, err := os.Open(filename)
exitErr(err)
defer closeOnce.Do(func() { file.Close() })
src, err := readahead.NewReaderSize(file, *cpu, int(sz))
exitErr(err)
defer src.Close()
finfo, err := file.Stat()
exitErr(err)
var out io.Writer
switch {
case *bench > 0:
out = ioutil.Discard
case *stdout:
out = os.Stdout
default:
mode := finfo.Mode() // use the same mode for the output file
if *safe {
_, err := os.Stat(dstFilename)
if !os.IsNotExist(err) {
exitErr(errors.New("destination file exists"))
}
}
dstFile, err := os.OpenFile(dstFilename, os.O_CREATE|os.O_WRONLY, mode)
exitErr(err)
defer dstFile.Close()
bw := bufio.NewWriterSize(dstFile, int(sz)*2)
defer bw.Flush()
out = bw
}
wc := wCounter{out: out}
wr.Reset(&wc)
defer wr.Close()
start := time.Now()
input, err := wr.ReadFrom(src)
exitErr(err)
err = wr.Close()
exitErr(err)
if !*quiet {
elapsed := time.Since(start)
mbpersec := (float64(input) / (1024 * 1024)) / (float64(elapsed) / (float64(time.Second)))
pct := float64(wc.n) * 100 / float64(input)
fmt.Printf("%d -> %d [%.02f%%]; %.01fMB/s\n", input, wc.n, pct, mbpersec)
}
if *remove {
closeOnce.Do(func() {
file.Close()
err := os.Remove(filename)
exitErr(err)
})
}
}()
}
}
func exitErr(err error) {
if err != nil {
fmt.Fprintln(os.Stderr, "ERROR:", err.Error())
os.Exit(2)
}
}
// toSize converts a size indication to bytes.
func toSize(size string) (uint64, error) {
size = strings.ToUpper(strings.TrimSpace(size))
firstLetter := strings.IndexFunc(size, unicode.IsLetter)
if firstLetter == -1 {
firstLetter = len(size)
}
bytesString, multiple := size[:firstLetter], size[firstLetter:]
bytes, err := strconv.ParseUint(bytesString, 10, 64)
if err != nil {
return 0, fmt.Errorf("unable to parse size: %v", err)
}
switch multiple {
case "M", "MB", "MIB":
return bytes * 1 << 20, nil
case "K", "KB", "KIB":
return bytes * 1 << 10, nil
case "B", "":
return bytes, nil
default:
return 0, fmt.Errorf("unknown size suffix: %v", multiple)
}
}
type wCounter struct {
n int
out io.Writer
}
func (w *wCounter) Write(p []byte) (n int, err error) {
n, err = w.out.Write(p)
w.n += n
return n, err
}