Initial work on implementing support for cheats

arm9/source/cheats/UsrCheatRepository.cpp

@@ -0,0 +1,174 @@
+#include "common.h"
+#include <algorithm>
+#include <string.h>
+#include "UsrCheatRepository.h"
+
+std::unique_ptr<GameCheats> UsrCheatRepository::GetCheatsForGame(u32 gameCode, u32 headerCrc32) const
+{
+    auto index = FindIndex(gameCode, headerCrc32);
+    if (index == nullptr)
+    {
+        LOG_DEBUG("Cheats not found for %c%c%c%c - 0x%X\n",
+            gameCode & 0xFF, (gameCode >> 8) & 0xFF, (gameCode >> 16) & 0xFF, gameCode >> 24,
+            headerCrc32);
+        return nullptr;
+    }
+
+    auto cheatData = std::make_unique_for_overwrite<u8[]>(index->padding); // padding was set to the size in UsrCheatRepositoryFactory
+    if (_usrCheatFile->Seek(index->offset) != FR_OK)
+    {
+        LOG_ERROR("Failed to seek to cheat data\n");
+        return nullptr;
+    }
+    if (!_usrCheatFile->ReadExact(cheatData.get(), index->padding))
+    {
+        LOG_ERROR("Failed to read cheat data\n");
+        return nullptr;
+    }
+
+    u8* ptr = cheatData.get();
+
+    // game name
+    const char* gameName = (const char*)ptr;
+    ptr += strlen(gameName) + 1;
+
+    // padding
+    ptr = (u8*)(((u32)ptr + 3) & ~3); // 32-bit align
+
+    // flags
+    u32 flags = *(u32*)ptr;
+    u32 totalNumberOfItems = flags & 0x0FFFFFFF;
+    u32 gameActive = flags >> 28;
+    ptr += 4;
+
+    // master codes
+    ptr += 8 * 4;
+
+    auto categories = (CheatCategory*)malloc(totalNumberOfItems * sizeof(CheatCategory));
+    u32 categoryCount = 0;
+
+    auto cheats = (Cheat*)malloc(totalNumberOfItems * sizeof(Cheat));
+    u32 cheatCount = 0;
+
+    while (ptr < cheatData.get() + index->padding)
+    {
+        u32 itemFlags = *(u32*)ptr;
+        bool isCategory = ((itemFlags >> 28) & 1) == 1;
+        if (isCategory)
+        {
+            ParseCategory(categories[categoryCount], ptr);
+            categoryCount++;
+        }
+        else
+        {
+            ParseCheat(cheats[cheatCount], ptr);
+            cheatCount++;
+        }
+    }
+
+    categories = (CheatCategory*)realloc(categories, categoryCount * sizeof(CheatCategory));
+    cheats = (Cheat*)realloc(cheats, cheatCount * sizeof(Cheat));
+
+    return std::make_unique<GameCheats>(std::move(cheatData), gameName, categories, categoryCount, cheats, cheatCount);
+}
+
+const usr_cheat_index_entry_t* UsrCheatRepository::FindIndex(u32 gameCode, u32 headerCrc32) const
+{
+    if (_numberOfIndices != 0)
+    {
+        const auto index = std::lower_bound(_sortedIndices.get(), _sortedIndices.get() + _numberOfIndices, gameCode,
+            [headerCrc32] (const usr_cheat_index_entry_t& entry, u32 value)
+            {
+                if (entry.gameCode != value)
+                {
+                    return entry.gameCode < value;
+                }
+
+                return entry.headerCrc32 < headerCrc32;
+            });
+
+        if (index != _sortedIndices.get() + _numberOfIndices &&
+            index->gameCode == gameCode &&
+            index->headerCrc32 == headerCrc32)
+        {
+            return index;
+        }
+    }
+
+    return nullptr;
+}
+
+void UsrCheatRepository::ParseCategory(CheatCategory& category, u8*& ptr) const
+{
+    // flags
+    u32 itemFlags = *(u32*)ptr;
+    ptr += 4;
+    u32 numberOfItems = itemFlags & 0x00FFFFFF;
+    bool isMaxOneCheatActive = ((itemFlags >> 24) & 1) == 1;
+
+    // item name
+    const char* itemName = (const char*)ptr;
+    ptr += strlen(itemName) + 1;
+
+    // item description
+    const char* itemDescription = (const char*)ptr;
+    ptr += strlen(itemDescription) + 1;
+
+    // padding
+    ptr = (u8*)(((u32)ptr + 3) & ~3); // 32-bit align
+
+    auto categories = (CheatCategory*)malloc(numberOfItems * sizeof(CheatCategory));
+    u32 categoryCount = 0;
+
+    auto cheats = (Cheat*)malloc(numberOfItems * sizeof(Cheat));
+    u32 cheatCount = 0;
+
+    for (u32 i = 0; i < numberOfItems; i++)
+    {
+        u32 itemFlags = *(u32*)ptr;
+        bool isCategory = ((itemFlags >> 28) & 1) == 1;
+        if (isCategory)
+        {
+            ParseCategory(categories[categoryCount], ptr);
+            categoryCount++;
+        }
+        else
+        {
+            ParseCheat(cheats[cheatCount], ptr);
+            cheatCount++;
+        }
+    }
+
+    categories = (CheatCategory*)realloc(categories, categoryCount * sizeof(CheatCategory));
+    cheats = (Cheat*)realloc(cheats, cheatCount * sizeof(Cheat));
+
+    category = CheatCategory(itemName, itemDescription, isMaxOneCheatActive, categories, categoryCount, cheats, cheatCount);
+}
+
+void UsrCheatRepository::ParseCheat(Cheat& cheat, u8*& ptr) const
+{
+    // flags
+    u32 itemFlags = *(u32*)ptr;
+    ptr += 4;
+    bool isCheatActive = ((itemFlags >> 24) & 1) == 1;
+
+    // item name
+    const char* itemName = (const char*)ptr;
+    ptr += strlen(itemName) + 1;
+
+    // item description
+    const char* itemDescription = (const char*)ptr;
+    ptr += strlen(itemDescription) + 1;
+
+    // padding
+    ptr = (u8*)(((u32)ptr + 3) & ~3); // 32-bit align
+
+    // number of code words
+    u32 numberOfCodeWords = *(u32*)ptr;
+    ptr += 4;
+
+    cheat = Cheat(itemName, itemDescription, isCheatActive, ptr, numberOfCodeWords * 4);
+
+    // code
+    ptr += numberOfCodeWords * 4;
+}