Make the support for unencrypted Wii disc images less broken

These disc images are only used on dev units and not retail units.
There are two important differences compared to normal Wii disc images:

- The data starts 0x8000 bytes into each partition instead of 0x20000
- The data of a partition is stored unencrypted and contains no hashes

Our old implementation was just guesswork and doesn't work at all.
According to testing by GerbilSoft, this commit's implementation
is able to read and extract files in the filesystem correctly,
but the tested game still isn't able to boot. (It's thanks to their
info about unencrypted disc images that I was able to make this commit.)

1 files changed, 5 insertions, 4 deletions

diff --git a/Source/Core/DiscIO/DirectoryBlob.cpp b/Source/Core/DiscIO/DirectoryBlob.cpp
index 61aac73694..8628c50fc0 100644
--- a/Source/Core/DiscIO/DirectoryBlob.cpp
+++ b/Source/Core/DiscIO/DirectoryBlob.cpp
@@ -54,6 +54,8 @@ enum class PartitionType : u32
 // 0xFF is an arbitrarily picked value. Note that we can't use 0x00, because that means NTSC-J
 constexpr u32 INVALID_REGION = 0xFF;
 
+constexpr u32 PARTITION_DATA_OFFSET = 0x20000;
+
 constexpr u8 ENTRY_SIZE = 0x0c;
 constexpr u8 FILE_ENTRY = 0;
 constexpr u8 DIRECTORY_ENTRY = 1;
@@ -508,8 +510,8 @@ void DirectoryBlobReader::SetPartitions(std::vector<PartitionWithType>&& partiti
 
     const u64 partition_data_size = partitions[i].partition.GetDataSize();
     m_partitions.emplace(partition_address, std::move(partitions[i].partition));
-    const u64 unaligned_next_partition_address =
-        VolumeWii::PartitionOffsetToRawOffset(partition_data_size, Partition(partition_address));
+    const u64 unaligned_next_partition_address = VolumeWii::EncryptedPartitionOffsetToRawOffset(
+        partition_data_size, Partition(partition_address), PARTITION_DATA_OFFSET);
     partition_address = Common::AlignUp(unaligned_next_partition_address, 0x10000ull);
   }
   m_data_size = partition_address;
@@ -546,7 +548,6 @@ void DirectoryBlobReader::SetPartitionHeader(const DirectoryBlobPartition& parti
                                           partition_root + "h3.bin");
 
   constexpr u32 PARTITION_HEADER_SIZE = 0x1c;
-  constexpr u32 DATA_OFFSET = 0x20000;
   const u64 data_size = Common::AlignUp(partition.GetDataSize(), 0x7c00) / 0x7c00 * 0x8000;
   m_partition_headers.emplace_back(PARTITION_HEADER_SIZE);
   std::vector<u8>& partition_header = m_partition_headers.back();
@@ -555,7 +556,7 @@ void DirectoryBlobReader::SetPartitionHeader(const DirectoryBlobPartition& parti
   Write32(static_cast<u32>(cert_size), 0x8, &partition_header);
   Write32(static_cast<u32>(cert_offset >> 2), 0x0C, &partition_header);
   Write32(H3_OFFSET >> 2, 0x10, &partition_header);
-  Write32(DATA_OFFSET >> 2, 0x14, &partition_header);
+  Write32(PARTITION_DATA_OFFSET >> 2, 0x14, &partition_header);
   Write32(static_cast<u32>(data_size >> 2), 0x18, &partition_header);
 
   m_nonpartition_contents.Add(partition_address + TICKET_SIZE, partition_header);