package main import ( "bufio" "crypto/md5" "crypto/sha1" "crypto/sha256" "crypto/sha512" "fmt" "hash" "io" "log" "os" "strings" "sync" ) type checksum struct { filename string hash hash.Hash checksum string } func parseCS(line string) (checksum, error) { elems := strings.Fields(line) if len(elems) != 2 { return checksum{}, fmt.Errorf("unexpected content: %d != 2", len(elems)) } cs, f := elems[0], elems[1] var hsh hash.Hash switch len(cs) { case 32: hsh = md5.New() case 40: hsh = sha1.New() case 64: hsh = sha256.New() case 128: hsh = sha512.New() default: return checksum{}, fmt.Errorf("unknown format: %q", line) } return checksum{filename: f, hash: hsh, checksum: cs}, nil } type input struct { f io.ReadCloser err error } type work struct { cs checksum err error } func streams(files []string) chan input { r := make(chan input) go func() { for _, name := range files { f, err := os.Open(name) r <- input{f, err} } if len(files) == 0 { r <- input{f: os.Stdin} } close(r) }() return r } func check(files []string) chan error { jobs := make(chan work) go func() { for stream := range streams(files) { if stream.err != nil { jobs <- work{err: stream.err} break } s := bufio.NewScanner(stream.f) for s.Scan() { cs, err := parseCS(s.Text()) jobs <- work{cs, err} } stream.f.Close() if s.Err() != nil { jobs <- work{err: s.Err()} } } close(jobs) }() results := []<-chan error{} for w := 0; w < *ngo; w++ { results = append(results, compute(jobs)) } return merge(results) } func merge(cs []<-chan error) chan error { out := make(chan error) var wg sync.WaitGroup output := func(c <-chan error) { for n := range c { out <- n } wg.Done() } wg.Add(len(cs)) for _, c := range cs { go output(c) } go func() { wg.Wait() close(out) }() return out } func compute(jobs chan work) chan error { r := make(chan error) go func() { for job := range jobs { if job.err != nil { log.Printf("%+v", job.err) continue } f, err := os.Open(job.cs.filename) if err != nil { r <- fmt.Errorf("open: %v", err) continue } if _, err := io.Copy(job.cs.hash, f); err != nil { r <- err continue } f.Close() if fmt.Sprintf("%x", job.cs.hash.Sum(nil)) != job.cs.checksum { r <- fmt.Errorf("%s: bad", job.cs.filename) } } close(r) }() return r }