next

pub fn next(it: *HeaderIterator) ?std.http.Header {
    const end = std.mem.indexOfPosLinear(u8, it.bytes, it.index, "\r\n").?;
    if (it.index == end) { // found the trailer boundary (\r\n\r\n)
        if (it.is_trailer) return null;

        const next_end = std.mem.indexOfPosLinear(u8, it.bytes, end + 2, "\r\n") orelse
            return null;

        var kv_it = std.mem.splitScalar(u8, it.bytes[end + 2 .. next_end], ':');
        const name = kv_it.first();
        const value = kv_it.rest();

        it.is_trailer = true;
        it.index = next_end + 2;
        if (name.len == 0)
            return null;

        return .{
            .name = name,
            .value = std.mem.trim(u8, value, " \t"),
        };
    } else { // normal header
        var kv_it = std.mem.splitScalar(u8, it.bytes[it.index..end], ':');
        const name = kv_it.first();
        const value = kv_it.rest();

        it.index = end + 2;
        if (name.len == 0)
            return null;

        return .{
            .name = name,
            .value = std.mem.trim(u8, value, " \t"),
        };
    }
}