From 6dc9508bf13d78a990a36b2b43e9fa498ddbe228 Mon Sep 17 00:00:00 2001
From: Felix Morgner <felix.morgner@gmail.com>
Date: Wed, 17 Jun 2026 20:14:45 +0200
Subject: lib: optimize buffer allocation

---
 ttwhy/io.cppm | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/ttwhy/io.cppm b/ttwhy/io.cppm
index cbd3902..353bdfa 100644
--- a/ttwhy/io.cppm
+++ b/ttwhy/io.cppm
@@ -27,11 +27,9 @@ namespace ttwhy::io
   }
 
   export template<typename InputStream, typename ErrorStream>
-  auto read(InputStream & input_stream, ErrorStream & error_stream)
-      -> asio::awaitable<std::expected<std::string, asio::error_code>>
+  auto read(std::span<char> data, InputStream & input_stream, ErrorStream & error_stream)
+      -> asio::awaitable<std::expected<std::size_t, asio::error_code>>
   {
-    auto data = std::string{15, '\0'};
-
     auto [error, read] = co_await input_stream.async_read_some(asio::buffer(data), asio::as_tuple(asio::use_awaitable));
 
     if (error)
@@ -41,12 +39,11 @@ namespace ttwhy::io
       co_return std::unexpected{error};
     }
 
-    data.resize(read);
-    co_return data;
+    co_return read;
   }
 
   export template<typename OutputStream, typename ErrorStream>
-  auto write(std::string const & string, OutputStream & output_stream, ErrorStream & error_stream)
+  auto write(std::span<char const> string, OutputStream & output_stream, ErrorStream & error_stream)
       -> asio::awaitable<asio::error_code>
   {
     auto [error, written] =
@@ -65,15 +62,18 @@ namespace ttwhy::io
   auto echo(InputStream & input_stream, OutputStream & output_stream, ErrorStream & error_stream)
       -> asio::awaitable<asio::error_code>
   {
+    auto input = std::array<char, 16>{};
+
     while (true)
     {
-      auto input = co_await read(input_stream, error_stream);
-      if (!input.has_value())
+      auto read_result = co_await read(input, input_stream, error_stream);
+      if (!read_result.has_value())
       {
-        co_return input.error();
+        co_return read_result.error();
       }
 
-      auto write_error = co_await write(input.value(), output_stream, error_stream);
+      auto to_write = std::span{input.data(), read_result.value()};
+      auto write_error = co_await write(to_write, output_stream, error_stream);
       if (write_error)
       {
         co_return write_error;
-- 
cgit v1.2.3