Attribute

    const Attribute = struct {
        kind: PaxAttributeKind,
        len: usize, // length of the attribute value
        reader: *Io.Reader, // reader positioned at value start

        // Copies pax attribute value into destination buffer.
        // Must be called with destination buffer of size at least Attribute.len.
        pub fn value(self: Attribute, dst: []u8) ![]const u8 {
            if (self.len > dst.len) return error.TarInsufficientBuffer;
            // assert(self.len <= dst.len);
            const buf = dst[0..self.len];
            const n = try self.reader.readSliceShort(buf);
            if (n < self.len) return error.UnexpectedEndOfStream;
            try validateAttributeEnding(self.reader);
            if (hasNull(buf)) return error.PaxNullInValue;
            return buf;
        }
    }