From 6c880159c927f87ae4013e32023eb89a5336b5a4 Mon Sep 17 00:00:00 2001
From: arvidn <arvid@libtorrent.org>
Date: Sat, 4 Apr 2020 13:38:31 +0200
Subject: [PATCH] fix bug in auto disk cache size logic

---
 ChangeLog                            | 1 +
 include/libtorrent/settings_pack.hpp | 1 +
 src/disk_buffer_pool.cpp             | 2 +-
 src/platform_util.cpp                | 2 +-
 src/settings_pack.cpp                | 6 ++++++
 5 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 78614a2d7..a50375f43 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,4 @@
+	* fix bug in auto disk cache size logic
 	* fix issue with outgoing_interfaces setting, where bind() would be called twice
 	* add build option to disable share-mode
 	* support validation of HTTPS trackers
diff --git a/include/libtorrent/settings_pack.hpp b/include/libtorrent/settings_pack.hpp
index e8e48f7d9..8341673f6 100644
--- a/include/libtorrent/settings_pack.hpp
+++ b/include/libtorrent/settings_pack.hpp
@@ -78,6 +78,7 @@ namespace aux {
 		, aux::session_settings_single_thread& sett
 		, std::vector<void(aux::session_impl::*)()>* callbacks = nullptr);
 	TORRENT_EXTRA_EXPORT void run_all_updates(aux::session_impl& ses);
+	TORRENT_EXTRA_EXPORT int default_int_value(int const name);
 
 	// converts a setting integer (from the enums string_types, int_types or
 	// bool_types) to a string, and vice versa.
diff --git a/src/disk_buffer_pool.cpp b/src/disk_buffer_pool.cpp
index 7c238d7c5..3d1b8248a 100644
--- a/src/disk_buffer_pool.cpp
+++ b/src/disk_buffer_pool.cpp
@@ -292,7 +292,7 @@ namespace libtorrent {
 		if (cache_size < 0)
 		{
 			std::int64_t phys_ram = total_physical_ram();
-			if (phys_ram == 0) m_max_use = 1024;
+			if (phys_ram == 0) m_max_use = default_int_value(settings_pack::cache_size);
 			else
 			{
 				// this is the logic to calculate the automatic disk cache size
diff --git a/src/platform_util.cpp b/src/platform_util.cpp
index 9ce1ac1cb..8b5298d13 100644
--- a/src/platform_util.cpp
+++ b/src/platform_util.cpp
@@ -112,7 +112,7 @@ namespace libtorrent {
 		MEMORYSTATUSEX ms;
 		ms.dwLength = sizeof(MEMORYSTATUSEX);
 		if (GlobalMemoryStatusEx(&ms))
-			ret = int(ms.ullTotalPhys);
+			ret = ms.ullTotalPhys;
 		else
 			ret = 0;
 #elif defined TORRENT_LINUX
diff --git a/src/settings_pack.cpp b/src/settings_pack.cpp
index 3488d75db..15d9c8e42 100644
--- a/src/settings_pack.cpp
+++ b/src/settings_pack.cpp
@@ -531,6 +531,12 @@ constexpr int CLOSE_FILE_INTERVAL = 0;
 		return ret;
 	}
 
+	int default_int_value(int const name)
+	{
+		TORRENT_ASSERT((name & settings_pack::type_mask) == settings_pack::int_type_base);
+		return int_settings[name - settings_pack::int_type_base].default_value;
+	}
+
 	void apply_pack(settings_pack const* pack, aux::session_settings& sett
 		, aux::session_impl* ses)
 	{