Keep track of scheduled messages.

Telegram/SourceFiles/api/api_hash.h

@@ -0,0 +1,37 @@
+/*
+This file is part of Telegram Desktop,
+the official desktop application for the Telegram messaging service.
+
+For license and copyright information please follow this link:
+https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
+*/
+#pragma once
+
+namespace Api {
+
+uint32 HashInit() {
+	return 0;
+}
+
+template <
+	typename Int,
+	typename = std::enable_if_t<
+		std::is_same_v<Int, int32> || std::is_same_v<Int, uint32>>>
+void HashUpdate(uint32 &already, Int value) {
+	already += (already * 20261) + uint32(value);
+}
+
+int32 HashFinalize(uint32 already) {
+	return int32(already & 0x7FFFFFFF);
+}
+
+template <typename IntRange>
+inline int32 CountHash(IntRange &&range) {
+	auto result = HashInit();
+	for (const auto value : range) {
+		HashUpdate(result, value);
+	}
+	return HashFinalize(result);
+}
+
+} // namespace Api