Method GetFileEntryFromFileDataCluster

pcsx2/SIO/Memcard/MemoryCardFolder.cpp:840–893

This method is actually unused since the introduction of m_fileMetadataQuickAccess. I'll leave it here anyway though to show how you traverse the file system.

// This method is actually unused since the introduction of m_fileMetadataQuickAccess.
// I'll leave it here anyway though to show how you traverse the file system.
MemoryCardFileEntry* FolderMemoryCard::GetFileEntryFromFileDataCluster(const u32 currentCluster, const u32 searchCluster, std::string* fileName, const size_t originalDirCount, u32* outClusterNumber)
{
	// check both entries of the current cluster if they're the file we're searching for, and if yes return it
	for (int i = 0; i < 2; ++i)
	{
		MemoryCardFileEntry* const entry = &m_fileEntryDict[currentCluster].entries[i];
		if (entry->IsValid() && entry->IsUsed() && entry->IsFile())
		{
			u32 fileCluster = entry->entry.data.cluster;
			u32 clusterNumber = 0;
			do
			{
				if (fileCluster == searchCluster)
				{
					Path::ChangeFileName(fileName, (const char*)entry->entry.data.name);
					*outClusterNumber = clusterNumber;
					return entry;
				}
				++clusterNumber;
			} while ((fileCluster = m_fat.data[0][0][fileCluster] & NextDataClusterMask) != LastDataCluster);
		}
	}

	// check other clusters of this directory
	// this can probably be solved more efficiently by looping through nextClusters instead of recursively calling
	const u32 nextCluster = m_fat.data[0][0][currentCluster] & NextDataClusterMask;
	if (nextCluster != LastDataCluster)
	{
		MemoryCardFileEntry* ptr = GetFileEntryFromFileDataCluster(nextCluster, searchCluster, fileName, originalDirCount, outClusterNumber);
		if (ptr != nullptr)
		{
			return ptr;
		}
	}

	// check subdirectories
	for (int i = 0; i < 2; ++i)
	{
		MemoryCardFileEntry* const entry = &m_fileEntryDict[currentCluster].entries[i];
		if (entry->IsValid() && entry->IsUsed() && entry->IsDir() && !entry->IsDotDir())
		{
			MemoryCardFileEntry* ptr = GetFileEntryFromFileDataCluster(entry->entry.data.cluster, searchCluster, fileName, originalDirCount, outClusterNumber);
			if (ptr != nullptr)
			{
				std::vector<std::string_view> components(Path::SplitNativePath(*fileName));
				components.insert(components.begin() + originalDirCount, (const char*)entry->entry.data.name);
				*fileName = Path::JoinNativePath(components);
				return ptr;
			}
		}
	}

	return nullptr;
}

bool FolderMemoryCard::ReadFromFile(u8* dest, u32 adr, u32 dataLength)
{