diff --git a/src/DB.zig b/src/DB.zig
index b81ea93..5a2665f 100644
--- a/src/DB.zig
+++ b/src/DB.zig
@@ -204,39 +204,73 @@ pub fn iov(self: *const DB) BoundedArray(os.iovec_const, DB_fields.len * 2) {
     return result;
 }
 
-pub fn fromBytes(buf: []align(8) const u8) InvalidHeader!DB {
-    const header = try Header.fromBytes(buf[0..@sizeOf(Header)]);
-    // At first the tuple below had field names too, but moved it to comments,
-    // because it segfaulted. https://github.com/ziglang/zig/issues/3915 and
-    // https://paste.sr.ht/~motiejus/2830736e796801517c1fa8639be6615cd56ada27
-    const lengths = .{
-        header.nblocks_bdz_gid, // bdz_gid
-        header.nblocks_bdz_groupname, // bdz_groupname
-        header.nblocks_bdz_uid, // bdz_uid
-        header.nblocks_bdz_username, // bdz_username
-        nblocks_n(u32, header.num_groups * 4), // idx_gid2group
-        nblocks_n(u32, header.num_groups * 4), // idx_groupname2group
-        nblocks_n(u32, header.num_users * 4), // idx_uid2user
-        nblocks_n(u32, header.num_users * 4), // idx_name2user
-        nblocks_n(u16, header.num_shells * 2), // shell_index
-        header.nblocks_shell_blob, // shell_blob
-        header.nblocks_groups, // groups
-        header.nblocks_users, // users
-        header.nblocks_groupmembers, // groupmembers
-        header.nblocks_additional_gids, // additional_gids
-    };
+const DBNumbers = struct {
+    header: u64,
+    bdz_gid: u64,
+    bdz_groupname: u64,
+    bdz_uid: u64,
+    bdz_username: u64,
+    idx_gid2group: u64,
+    idx_groupname2group: u64,
+    idx_uid2user: u64,
+    idx_name2user: u64,
+    shell_index: u64,
+    shell_blob: u64,
+    groups: u64,
+    users: u64,
+    groupmembers: u64,
+    additional_gids: u64,
+};
 
-    var result: DB = undefined;
-    result.header = header;
+// in blocks
+fn fieldLengths(header: *const Header) DBNumbers {
+    return DBNumbers{
+        .header = undefined,
+        .bdz_gid = header.nblocks_bdz_gid,
+        .bdz_groupname = header.nblocks_bdz_groupname,
+        .bdz_uid = header.nblocks_bdz_uid,
+        .bdz_username = header.nblocks_bdz_username,
+        .idx_gid2group = nblocks_n(u32, header.num_groups * 4),
+        .idx_groupname2group = nblocks_n(u32, header.num_groups * 4),
+        .idx_uid2user = nblocks_n(u32, header.num_users * 4),
+        .idx_name2user = nblocks_n(u32, header.num_users * 4),
+        .shell_index = nblocks_n(u16, header.num_shells * 2),
+        .shell_blob = header.nblocks_shell_blob,
+        .groups = header.nblocks_groups,
+        .users = header.nblocks_users,
+        .groupmembers = header.nblocks_groupmembers,
+        .additional_gids = header.nblocks_additional_gids,
+    };
+}
+
+// in blocks
+fn fieldOffsets(lengths: DBNumbers) DBNumbers {
+    var result: DBNumbers = undefined;
+    result.header = 0;
     var offset = comptime nblocks_n(u64, @sizeOf(Header));
     comptime assert(mem.eql(u8, DB_fields[0].name, "header"));
     inline for (DB_fields[1..]) |field, i| {
-        const start = offset << section_length_bits;
-        const end = (offset + lengths[i]) << section_length_bits;
+        comptime assert(mem.eql(u8, field.name, meta.fields(DBNumbers)[i + 1].name));
+        @field(result, field.name) = offset;
+        offset += @field(lengths, field.name);
+    }
+    return result;
+}
+
+pub fn fromBytes(buf: []align(8) const u8) InvalidHeader!DB {
+    const header = try Header.fromBytes(buf[0..@sizeOf(Header)]);
+    const lengths = fieldLengths(header);
+    const offsets = fieldOffsets(lengths);
+
+    var result: DB = undefined;
+    result.header = header;
+    inline for (DB_fields[1..]) |field| {
+        const start_block = @field(offsets, field.name);
+        const end = (start_block + @field(lengths, field.name)) << section_length_bits;
+        const start = start_block << section_length_bits;
         const slice_type = meta.Child(field.field_type);
         const value = mem.bytesAsSlice(slice_type, buf[start..end]);
         @field(result, field.name) = value;
-        offset += lengths[i];
     }
 
     return result;