bugfix(controlbar): Fix possible divisions by zero in Control Bar code

[Caball009]

• Related issue: Division by zero crash in W3DCommandBarGenExpDraw() when experience points for level up are 0 #797
• Follow-up for PR: [GEN][ZH] Fix possible division by zero in W3DCommandBarGenExpDraw() #810

Using the modified rank file in #797, there are two more places the game would crash because of a division by zero; in ControlBar::populatePurchaseScience and ControlBar::updateContextPurchaseScience.

Issue reproduction steps:

1. Add the modified rank ini data to a custom map.
2. Start a match and click on the special powers menu.
3. Game crashes due to a division by zero.

Callstacks:

generalszh.exe!ControlBar::populatePurchaseScience(Player * player) Line 430
generalszh.exe!ControlBar::showPurchaseScience() Line 2977
generalszh.exe!ControlBar::togglePurchaseScience() Line 3016
generalszh.exe!ControlBarSystem(GameWindow * window, unsigned int msg, unsigned int mData1, unsigned int mData2) Line 418
generalszh.exe!GameWindowManager::winSendSystemMsg(GameWindow * window, unsigned int msg, unsigned int mData1, unsigned int mData2) Line 705
generalszh.exe!GadgetPushButtonInput(GameWindow * window, unsigned int msg, unsigned int mData1, unsigned int mData2) Line 218
generalszh.exe!GameWindowManager::winSendInputMsg(GameWindow * window, unsigned int msg, unsigned int mData1, unsigned int mData2) Line 724
generalszh.exe!GameWindowManager::winProcessMouseEvent(GameWindowMessage msg, ICoord2D * mousePos, void * data) Line 919
generalszh.exe!WindowTranslator::translateGameMessage(const GameMessage * msg) Line 242
generalszh.exe!MessageStream::propagateMessages() Line 1090
generalszh.exe!GameEngine::update() Line 910
generalszh.exe!Win32GameEngine::update() Line 91
generalszh.exe!GameEngine::execute() Line 983
generalszh.exe!GameMain() Line 55
generalszh.exe!WinMain(HINSTANCE__ * hInstance, HINSTANCE__ * hPrevInstance, char * lpCmdLine, int nCmdShow) Line 929

generalszh.exe!ControlBar::updateContextPurchaseScience() Line 495
generalszh.exe!ControlBar::update() Line 1530
generalszh.exe!InGameUI::update() Line 2093
generalszh.exe!W3DInGameUI::update() Line 370
generalszh.exe!SubsystemInterface::UPDATE() Line 131
generalszh.exe!GameClient::update() Line 781
generalszh.exe!W3DGameClient::update() Line 94
generalszh.exe!SubsystemInterface::UPDATE() Line 131
generalszh.exe!GameEngine::update() Line 910
generalszh.exe!Win32GameEngine::update() Line 91
generalszh.exe!GameEngine::execute() Line 983
generalszh.exe!GameMain() Line 55
generalszh.exe!WinMain(HINSTANCE__ * hInstance, HINSTANCE__ * hPrevInstance, char * lpCmdLine, int nCmdShow) Line 929

TODO:

• Replicate in Generals.

[greptile-apps]

Greptile Summary

This PR updates rank-bound handling to avoid invalid control-bar progress calculations. The main changes are:

• Normalize equal rank bounds in the Zero Hour player state.
• Apply normalization after loading player data.
• Use the normalized bounds in purchase-science and experience-bar progress calculations.

Confidence Score: 5/5

This looks safe to merge.

• No blocking issues found in the changed code.

Important Files Changed

Filename	Overview
Core/GameEngine/Source/GameClient/GUI/ControlBar/ControlBar.cpp	Keeps both purchase-science progress calculations aligned with the player rank bounds.
Core/GameEngineDevice/Source/W3DDevice/GameClient/GUI/GUICallbacks/W3DControlBar.cpp	Updates general-experience progress rendering to use the player rank interval directly.
GeneralsMD/Code/GameEngine/Include/Common/Player.h	Declares the private helper for normalizing rank bounds.
GeneralsMD/Code/GameEngine/Source/Common/RTS/Player.cpp	Uses the new helper during rank reset, rank changes, and post-load processing.

_{Reviews (11): Last reviewed commit: "Avoided possible divisions by zero in Co..." | Re-trigger Greptile}

[Skyaero42]

If skillPointsRequired is 0, than this implies that a rank up didn't go through - after all the player has enough points to rank up to the next level. So I wonder if the fix is at the wrong place

[xezon]

This code now exists at 3 locations. Maybe consolidate it to one?

[Caball009]

@greptileai re-review this pull request.

[xezon]

How about we introduce a hasNextRank function? Then it can be explicitly tested whether it has a next rank.

Reason: The current interface sort of implies that it can reach this INT_MAX points level to reach the next rank, but it is not possible.

[Caball009]

I'm not sure I understand. Is this relevant to the division by zero?

[xezon]

Yes. Right now the code relies on MAX_INT to work, but its shady.

[Caball009]

Perhaps you can post some code for what you have in mind.

[greptile-apps]

Do not terminalize duplicates

Equal adjacent SkillPointsNeeded values are valid custom-rank input for the crash case this code handles. When a player reaches rank N and rank N+1 has the same threshold, this branch replaces the next threshold with INT_MAX; addSkillPoints() can then never advance the player to rank N+1 even though the threshold is already met. Handle a zero-width transition without converting it into the terminal-rank sentinel.

Prompt To Fix With AI

This is a comment left during a code review.
Path: GeneralsMD/Code/GameEngine/Source/Common/RTS/Player.cpp
Line: 2794-2799

Comment:
**Do not terminalize duplicates**

Equal adjacent `SkillPointsNeeded` values are valid custom-rank input for the crash case this code handles. When a player reaches rank N and rank N+1 has the same threshold, this branch replaces the next threshold with `INT_MAX`; `addSkillPoints()` can then never advance the player to rank N+1 even though the threshold is already met. Handle a zero-width transition without converting it into the terminal-rank sentinel.

How can I resolve this? If you propose a fix, please make it concise.