reader.go

   1 package main
   2
   3 import (
   4         "bufio"
   5         "encoding/binary"
   6         "io"
   7         "log"
   8
   9         "github.com/klauspost/compress/zstd"
  10 )
  11
  12 func mustReadFull(r io.Reader, buf []byte) {
  13         if _, err := io.ReadFull(r, buf); err != nil {
  14                 log.Fatalln(err)
  15         }
  16 }
  17
  18 func reader(src io.Reader, sink chan Ent) {
  19         comp, err := zstd.NewReader(src)
  20         if err != nil {
  21                 log.Fatalln(err)
  22         }
  23         br := bufio.NewReaderSize(comp, 1<<17)
  24
  25         num := make([]byte, 8)
  26         var cols []string
  27         var namePrev string
  28         var nameLen uint16
  29         var depth, depthPrev uint8
  30         for {
  31                 _, err = io.ReadFull(br, num[:2])
  32                 if err != nil {
  33                         if err == io.EOF {
  34                                 break
  35                         }
  36                         log.Fatalln(err)
  37                 }
  38                 nameLen = binary.BigEndian.Uint16(num[:2])
  39                 nameRaw := make([]byte, nameLen)
  40                 mustReadFull(br, nameRaw)
  41                 name := string(nameRaw)
  42                 mustReadFull(br, num[:1])
  43                 depth = uint8(num[0])
  44                 mustReadFull(br, num)
  45                 ent := Ent{mtime: int64(binary.BigEndian.Uint64(num))}
  46                 mustReadFull(br, num)
  47                 ent.size = int64(binary.BigEndian.Uint64(num))
  48                 if depth > depthPrev {
  49                         cols = append(cols, namePrev[:len(namePrev)-1])
  50                 } else if depth < depthPrev {
  51                         cols = cols[:len(cols)-int(depthPrev-depth)]
  52                 }
  53                 ent.name = append([]string{}, append(cols, name)...)
  54                 sink <- ent
  55                 namePrev = name
  56                 depthPrev = depth
  57         }
  58         close(sink)
  59         comp.Close()
  60 }