Initial work on implementing support for cheats

arm9/source/romBrowser/viewModels/CheatsViewModel.cpp

@@ -0,0 +1,66 @@
+#include "common.h"
+#include "cheats/ICheatRepository.h"
+#include "fat/File.h"
+#include "CheatsViewModel.h"
+
+#define CRCPOLY 0xEDB88320
+
+static u32 crc32(const void* buffer, u32 length)
+{
+    u32 crc = ~0u;
+    const u8* p = (u8*)buffer;
+    while (length--)
+    {
+        crc ^= *p++;
+        for (int i = 0; i < 8; i++)
+        {
+            crc = (crc >> 1) ^ ((crc & 1) ? CRCPOLY : 0);
+        }
+    }
+
+    return crc;
+}
+
+CheatsViewModel::CheatsViewModel(const FileInfo& romFileInfo, IRomBrowserController* romBrowserController)
+    : _romFileInfo(romFileInfo), _romBrowserController(romBrowserController)
+{
+    _loadCheatsTask = _romBrowserController->GetIoTaskQueue()->Enqueue([this] (const vu8& cancelRequested)
+    {
+        LOG_DEBUG("%s\n", _romFileInfo.GetFileName());
+        auto file = std::make_unique<File>();
+        file->Open(_romFileInfo.GetFastFileRef(), FA_READ);
+        auto headerBuffer = std::make_unique_for_overwrite<u8[]>(512);
+        if (!file->ReadExact(headerBuffer.get(), 512))
+        {
+            LOG_ERROR("Could not read rom header\n");
+            return TaskResult<void>::Failed();
+        }
+        file->Close();
+
+        if (cancelRequested)
+        {
+            return TaskResult<void>::Canceled();
+        }
+
+        u32 gameCode = *(u32*)(headerBuffer.get() + 0xC);
+        u32 crc = crc32(headerBuffer.get(), 512);
+        headerBuffer.reset();
+
+        if (cancelRequested)
+        {
+            return TaskResult<void>::Canceled();
+        }
+
+        _cheats = _romBrowserController->GetCheatRepository().GetCheatsForGame(gameCode, crc);
+        if (_cheats)
+        {
+            _state = State::DisplayCheats;
+        }
+        else
+        {
+            _state = State::NoCheats;
+        }
+
+        return TaskResult<void>::Completed();
+    });
+}