Move tracker protocol into it's own file

Change piece_length -> u32, protocol constrains that anyway
annnnd, successfully download a file (albeit from one torrent only with
no checking of a ton of stuff)

1 files changed, 9 insertions, 4 deletions

diff --git a/src/metainfo.zig b/src/metainfo.zig
index cd00438..04e8f64 100644
--- a/src/metainfo.zig
+++ b/src/metainfo.zig
@@ -12,7 +12,7 @@ pub const Info = struct {
         md5sum: ?[]const u8 = null,
     };
 
-    piece_length: u64,
+    piece_length: u32,
     pieces: []const u8,
     files: []File,
     private: ?bool,
@@ -68,7 +68,7 @@ pub const Info = struct {
         if (ps.len % 20 != 0) return error.Malformatted;
 
         return .{
-            .piece_length = pl.asInt(u64) catch return error.Malformatted,
+            .piece_length = pl.asInt(u32) catch return error.Malformatted,
             .pieces = ps,
             .files = try files.toOwnedSlice(),
             .private = priv,
@@ -116,10 +116,15 @@ pub const Info = struct {
         try b.bencode(w);
         return sha1.finalResult();
     }
-    pub fn pieceHash(self: Info, ix: usize) ?[]const u8 {
+    pub fn pieceHash(self: Info, ix: usize) ?[20]u8 {
         const start = 20 * ix;
         if (start >= self.pieces.len) return null;
-        return self.pieces[start .. start + 20];
+        var res: [20]u8 = undefined;
+        @memcpy(&res, self.pieces[start .. start + 20]);
+        return res;
+    }
+    pub fn pieceCount(self: Info) u32 {
+        return @as(u32, @intCast(self.pieces.len)) / 20;
     }
 };