codecrafters submit [skip ci]

1 files changed, 37 insertions, 0 deletions

diff --git a/cmd/mybittorrent/meta.go b/cmd/mybittorrent/meta.go
new file mode 100644
index 0000000..34369c4
--- /dev/null
+++ b/cmd/mybittorrent/meta.go
@@ -0,0 +1,37 @@
+package main
+
+import (
+	"crypto/sha1"
+
+	bencode "github.com/jackpal/bencode-go"
+)
+
+type Meta struct {
+	Announce string   `bencode:"announce"`
+	Info     FileInfo `bencode:"info"`
+}
+
+type FileInfo struct {
+	Length      int    `bencode:"length"`
+	Name        string `bencode:"name"`
+	PieceLength int    `bencode:"piece length"`
+	Pieces      string `bencode:"pieces"`
+}
+
+func (m Meta) InfoHash() ([]byte, error) {
+	sha := sha1.New()
+	if err := bencode.Marshal(sha, m.Info); err != nil {
+		return nil, err
+	}
+
+	return sha.Sum(nil), nil
+}
+
+func (m Meta) PieceHashes() []string {
+	hashes := make([]string, 0, len(m.Info.Pieces)/20)
+	for i := 0; i < len(m.Info.Pieces); i += 20 {
+		hashes = append(hashes, m.Info.Pieces[i:i+20])
+	}
+
+	return hashes
+}