1 files changed, 99 insertions, 0 deletions
diff --git a/src/contrib/libngtcp2/ngtcp2/lib/ngtcp2_window_filter.c b/src/contrib/libngtcp2/ngtcp2/lib/ngtcp2_window_filter.c
new file mode 100644
index 0000000..71c816e
--- /dev/null
+++ b/src/contrib/libngtcp2/ngtcp2/lib/ngtcp2_window_filter.c
@@ -0,0 +1,99 @@
+/*
+ * ngtcp2
+ *
+ * Copyright (c) 2021 ngtcp2 contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+/*
+ * Translated to C from the original C++ code
+ * https://quiche.googlesource.com/quiche/+/5be974e29f7e71a196e726d6e2272676d33ab77d/quic/core/congestion_control/windowed_filter.h
+ * with the following license:
+ *
+ * // Copyright (c) 2016 The Chromium Authors. All rights reserved.
+ * // Use of this source code is governed by a BSD-style license that can be
+ * // found in the LICENSE file.
+ */
+#include "ngtcp2_window_filter.h"
+
+#include <string.h>
+
+void ngtcp2_window_filter_init(ngtcp2_window_filter *wf,
+                               uint64_t window_length) {
+  wf->window_length = window_length;
+  memset(wf->estimates, 0, sizeof(wf->estimates));
+}
+
+void ngtcp2_window_filter_update(ngtcp2_window_filter *wf, uint64_t new_sample,
+                                 uint64_t new_time) {
+  if (wf->estimates[0].sample == 0 || new_sample > wf->estimates[0].sample ||
+      new_time - wf->estimates[2].time > wf->window_length) {
+    ngtcp2_window_filter_reset(wf, new_sample, new_time);
+    return;
+  }
+
+  if (new_sample > wf->estimates[1].sample) {
+    wf->estimates[1].sample = new_sample;
+    wf->estimates[1].time = new_time;
+    wf->estimates[2] = wf->estimates[1];
+  } else if (new_sample > wf->estimates[2].sample) {
+    wf->estimates[2].sample = new_sample;
+    wf->estimates[2].time = new_time;
+  }
+
+  if (new_time - wf->estimates[0].time > wf->window_length) {
+    wf->estimates[0] = wf->estimates[1];
+    wf->estimates[1] = wf->estimates[2];
+    wf->estimates[2].sample = new_sample;
+    wf->estimates[2].time = new_time;
+
+    if (new_time - wf->estimates[0].time > wf->window_length) {
+      wf->estimates[0] = wf->estimates[1];
+      wf->estimates[1] = wf->estimates[2];
+    }
+    return;
+  }
+
+  if (wf->estimates[1].sample == wf->estimates[0].sample &&
+      new_time - wf->estimates[1].time > wf->window_length >> 2) {
+    wf->estimates[2].sample = new_sample;
+    wf->estimates[2].time = new_time;
+    wf->estimates[1] = wf->estimates[2];
+    return;
+  }
+
+  if (wf->estimates[2].sample == wf->estimates[1].sample &&
+      new_time - wf->estimates[2].time > wf->window_length >> 1) {
+    wf->estimates[2].sample = new_sample;
+    wf->estimates[2].time = new_time;
+  }
+}
+
+void ngtcp2_window_filter_reset(ngtcp2_window_filter *wf, uint64_t new_sample,
+                                uint64_t new_time) {
+  wf->estimates[0].sample = new_sample;
+  wf->estimates[0].time = new_time;
+  wf->estimates[1] = wf->estimates[2] = wf->estimates[0];
+}
+
+uint64_t ngtcp2_window_filter_get_best(ngtcp2_window_filter *wf) {
+  return wf->estimates[0].sample;
+}