From f65b1f1c14522f0887b77294d56c617dc06c153c Mon Sep 17 00:00:00 2001
From: Martin Michelsen <fuzziqersoftware+g@gmail.com>
Date: Fri, 25 Apr 2025 08:56:19 -0700
Subject: [PATCH] make login faster with MoreSaveSlots

---
 src/CommandFormats.hh                         |  4 ++
 src/ReceiveCommands.cc                        | 41 +++++++++++++------
 .../MoreSaveSlots.59NL.patch.s                | 22 ++++++++++
 3 files changed, 55 insertions(+), 12 deletions(-)

diff --git a/src/CommandFormats.hh b/src/CommandFormats.hh
index e2b8e494..36080c4f 100644
--- a/src/CommandFormats.hh
+++ b/src/CommandFormats.hh
@@ -3109,6 +3109,10 @@ check_struct_size(S_TournamentGameDetails_Ep3NTE_E3, 0x734);
 check_struct_size(S_TournamentGameDetails_Ep3_E3, 0x73C);
 
 // E3 (C->S): Player preview request (BB)
+// header.flag is not used by the vanilla client, but newserv's MoreSaveSlots
+// patch uses header.flag to tell the server how many save slots the client
+// expects. The server uses this to send all the character previews at once,
+// thus reducing the number of network roundtrips during login.
 
 struct C_PlayerPreviewRequest_BB_E3 {
   le_int32_t character_index = 0;
diff --git a/src/ReceiveCommands.cc b/src/ReceiveCommands.cc
index 8075e71a..d06f3121 100644
--- a/src/ReceiveCommands.cc
+++ b/src/ReceiveCommands.cc
@@ -3616,13 +3616,12 @@ static void on_E0_BB(shared_ptr<Client> c, uint16_t, uint32_t, string& data) {
   send_system_file_bb(c);
 }
 
-static void on_E3_BB(shared_ptr<Client> c, uint16_t, uint32_t, string& data) {
+static void on_E3_BB(shared_ptr<Client> c, uint16_t, uint32_t flag, string& data) {
   const auto& cmd = check_size_t<C_PlayerPreviewRequest_BB_E3>(data);
 
-  c->save_and_unload_character();
-  c->bb_character_index = cmd.character_index;
-
   if (c->bb_connection_phase != 0x00) {
+    c->save_and_unload_character();
+    c->bb_character_index = cmd.character_index;
     send_approve_player_choice_bb(c);
 
   } else {
@@ -3631,15 +3630,33 @@ static void on_E3_BB(shared_ptr<Client> c, uint16_t, uint32_t, string& data) {
       return;
     }
 
-    auto s = c->require_server_state();
-    try {
-      auto preview = c->character()->to_preview();
-      send_player_preview_bb(c, cmd.character_index, &preview);
+    auto send_preview = [&c](size_t index) -> void {
+      c->save_and_unload_character();
+      c->bb_character_index = index;
+      try {
+        auto preview = c->character()->to_preview();
+        send_player_preview_bb(c, c->bb_character_index, &preview);
 
-    } catch (const exception& e) {
-      // Player doesn't exist
-      c->log.warning("Can\'t load character data: %s", e.what());
-      send_player_preview_bb(c, cmd.character_index, nullptr);
+      } catch (const exception& e) {
+        // Player doesn't exist
+        c->log.warning("Can\'t load character data: %s", e.what());
+        send_player_preview_bb(c, c->bb_character_index, nullptr);
+      }
+    };
+
+    if (flag == 0) {
+      if (cmd.character_index < 0 || cmd.character_index >= 0x80) {
+        throw runtime_error("client requested invalid character slot");
+      }
+      send_preview(cmd.character_index);
+    } else if (cmd.character_index == 0) {
+      if (flag >= 0x80) {
+        throw runtime_error("client requested too many character slots");
+      }
+      auto s = c->require_server_state();
+      for (size_t z = 0; z < flag; z++) {
+        send_preview(z);
+      }
     }
   }
 }
diff --git a/system/client-functions/BlueBurstExclusive/MoreSaveSlots.59NL.patch.s b/system/client-functions/BlueBurstExclusive/MoreSaveSlots.59NL.patch.s
index 629ff583..78d58b3b 100644
--- a/system/client-functions/BlueBurstExclusive/MoreSaveSlots.59NL.patch.s
+++ b/system/client-functions/BlueBurstExclusive/MoreSaveSlots.59NL.patch.s
@@ -479,6 +479,28 @@ sig_bad:
   .binary  CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC
 sig_check_end:  # 006C1C76
 
+  # Send slot count in E3 command
+  .data    0x0046EB20  # TDataProtocol::send_E3_for_index
+  .deltaof send_slot_count_in_E3_begin, send_slot_count_in_E3_end
+send_slot_count_in_E3_begin:
+  # ecx = this (TDataProtocol*)
+  # [esp + 4] = slot_index
+  push     0
+  push     dword [esp + 8]  # slot_index
+  push     0x0C  # slot count
+  push     0x00E30010
+  mov      eax, esp
+  push     0x10
+  push     eax
+  mov      eax, [ecx]
+  call     [eax + 0x20]  # this->send_command(&cmd, 0x10)  // ret 8
+  add      esp, 8
+  mov      eax, 0x006C1A80
+  call     eax  # set_current_char_slot(slot_index)  // ret 0
+  add      esp, 8
+  ret      4
+send_slot_count_in_E3_end:
+
   # Show slot number in each menu item
   .data    0x00401D57
   .deltaof show_slot_number_begin, show_slot_number_end