Merge pull request #10932 from JosJuice/nfs

DiscIO: Add support for the NFS format

Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/utils/FileBrowserHelper.java

@@ -30,7 +30,8 @@ import java.util.Set;
 public final class FileBrowserHelper
 {
   public static final HashSet<String> GAME_EXTENSIONS = new HashSet<>(Arrays.asList(
-          "gcm", "tgc", "iso", "ciso", "gcz", "wbfs", "wia", "rvz", "wad", "dol", "elf", "json"));
+          "gcm", "tgc", "iso", "ciso", "gcz", "wbfs", "wia", "rvz", "nfs", "wad", "dol", "elf",
+          "json"));
 
   public static final HashSet<String> GAME_LIKE_EXTENSIONS = new HashSet<>(GAME_EXTENSIONS);
 

Source/Core/Core/Boot/Boot.cpp

@@ -231,7 +231,7 @@ std::unique_ptr<BootParameters> BootParameters::GenerateFromFile(std::vector<std
 #endif
 
   static const std::unordered_set<std::string> disc_image_extensions = {
-      {".gcm", ".iso", ".tgc", ".wbfs", ".ciso", ".gcz", ".wia", ".rvz", ".dol", ".elf"}};
+      {".gcm", ".iso", ".tgc", ".wbfs", ".ciso", ".gcz", ".wia", ".rvz", ".nfs", ".dol", ".elf"}};
   if (disc_image_extensions.find(extension) != disc_image_extensions.end() || is_drive)
   {
     std::unique_ptr<DiscIO::VolumeDisc> disc = DiscIO::CreateDisc(path);

Source/Core/Core/HW/DVD/DVDInterface.cpp

@@ -430,9 +430,9 @@ void Shutdown()
 
 static u64 GetDiscEndOffset(const DiscIO::VolumeDisc& disc)
 {
-  u64 size = disc.GetSize();
+  u64 size = disc.GetDataSize();
 
-  if (disc.IsSizeAccurate())
+  if (disc.GetDataSizeType() == DiscIO::DataSizeType::Accurate)
   {
     if (size == DiscIO::MINI_DVD_SIZE)
       return DiscIO::MINI_DVD_SIZE;
@@ -464,7 +464,7 @@ void SetDisc(std::unique_ptr<DiscIO::VolumeDisc> disc,
   if (has_disc)
   {
     s_disc_end_offset = GetDiscEndOffset(*disc);
-    if (!disc->IsSizeAccurate())
+    if (disc->GetDataSizeType() != DiscIO::DataSizeType::Accurate)
       WARN_LOG_FMT(DVDINTERFACE, "Unknown disc size, guessing {0} bytes", s_disc_end_offset);
 
     const DiscIO::BlobReader& blob = disc->GetBlobReader();
@@ -1482,10 +1482,9 @@ static void ScheduleReads(u64 offset, u32 length, const DiscIO::Partition& parti
   u32 buffered_blocks = 0;
   u32 unbuffered_blocks = 0;
 
-  const u32 bytes_per_chunk =
-      partition != DiscIO::PARTITION_NONE && DVDThread::IsEncryptedAndHashed() ?
-          DiscIO::VolumeWii::BLOCK_DATA_SIZE :
-          DVD_ECC_BLOCK_SIZE;
+  const u32 bytes_per_chunk = partition != DiscIO::PARTITION_NONE && DVDThread::HasWiiHashes() ?
+                                  DiscIO::VolumeWii::BLOCK_DATA_SIZE :
+                                  DVD_ECC_BLOCK_SIZE;
 
   do
   {

Source/Core/Core/HW/DVD/DVDThread.cpp

@@ -184,10 +184,10 @@ bool HasDisc()
   return s_disc != nullptr;
 }
 
-bool IsEncryptedAndHashed()
+bool HasWiiHashes()
 {
-  // IsEncryptedAndHashed is thread-safe, so calling WaitUntilIdle isn't necessary.
-  return s_disc->IsEncryptedAndHashed();
+  // HasWiiHashes is thread-safe, so calling WaitUntilIdle isn't necessary.
+  return s_disc->HasWiiHashes();
 }
 
 DiscIO::Platform GetDiscType()

Source/Core/Core/HW/DVD/DVDThread.h

@@ -41,7 +41,7 @@ void DoState(PointerWrap& p);
 void SetDisc(std::unique_ptr<DiscIO::Volume> disc);
 bool HasDisc();
 
-bool IsEncryptedAndHashed();
+bool HasWiiHashes();
 DiscIO::Platform GetDiscType();
 u64 PartitionOffsetToRawOffset(u64 offset, const DiscIO::Partition& partition);
 IOS::ES::TMDReader GetTMD(const DiscIO::Partition& partition);

Source/Core/DiscIO/Blob.cpp

@@ -20,6 +20,7 @@
 #include "DiscIO/DirectoryBlob.h"
 #include "DiscIO/DriveBlob.h"
 #include "DiscIO/FileBlob.h"
+#include "DiscIO/NFSBlob.h"
 #include "DiscIO/TGCBlob.h"
 #include "DiscIO/WIABlob.h"
 #include "DiscIO/WbfsBlob.h"
@@ -52,6 +53,8 @@ std::string GetName(BlobType blob_type, bool translate)
     return "RVZ";
   case BlobType::MOD_DESCRIPTOR:
     return translate_str("Mod");
+  case BlobType::NFS:
+    return "NFS";
   default:
     return "";
   }
@@ -242,6 +245,8 @@ std::unique_ptr<BlobReader> CreateBlobReader(const std::string& filename)
     return WIAFileReader::Create(std::move(file), filename);
   case RVZ_MAGIC:
     return RVZFileReader::Create(std::move(file), filename);
+  case NFS_MAGIC:
+    return NFSFileReader::Create(std::move(file), filename);
   default:
     if (auto directory_blob = DirectoryBlobReader::Create(filename))
       return std::move(directory_blob);

Source/Core/DiscIO/Blob.h

@@ -40,6 +40,19 @@ enum class BlobType
   WIA,
   RVZ,
   MOD_DESCRIPTOR,
+  NFS,
+};
+
+// If you convert an ISO file to another format and then call GetDataSize on it, what is the result?
+enum class DataSizeType
+{
+  // The result is the same as for the ISO.
+  Accurate,
+  // The result is not larger than for the ISO. (It's usually a little smaller than for the ISO.)
+  // Reads to offsets that are larger than the result will return some kind of "blank" data.
+  LowerBound,
+  // The result is not smaller than for the ISO. (It's usually much larger than for the ISO.)
+  UpperBound,
 };
 
 std::string GetName(BlobType blob_type, bool translate);
@@ -53,7 +66,7 @@ public:
 
   virtual u64 GetRawSize() const = 0;
   virtual u64 GetDataSize() const = 0;
-  virtual bool IsDataSizeAccurate() const = 0;
+  virtual DataSizeType GetDataSizeType() const = 0;
 
   // Returns 0 if the format does not use blocks
   virtual u64 GetBlockSize() const = 0;

Source/Core/DiscIO/CISOBlob.h

@@ -38,10 +38,8 @@ public:
   BlobType GetBlobType() const override { return BlobType::CISO; }
 
   u64 GetRawSize() const override;
-  // The CISO format does not save the original file size.
-  // This function returns an upper bound.
   u64 GetDataSize() const override;
-  bool IsDataSizeAccurate() const override { return false; }
+  DataSizeType GetDataSizeType() const override { return DataSizeType::UpperBound; }
 
   u64 GetBlockSize() const override { return m_block_size; }
   bool HasFastRandomAccessInBlock() const override { return true; }

Source/Core/DiscIO/CMakeLists.txt

@@ -30,6 +30,8 @@ add_library(discio
   MultithreadedCompressor.h
   NANDImporter.cpp
   NANDImporter.h
+  NFSBlob.cpp
+  NFSBlob.h
   RiivolutionParser.cpp
   RiivolutionParser.h
   RiivolutionPatcher.cpp

Source/Core/DiscIO/CompressedBlob.cpp

@@ -273,7 +273,7 @@ bool ConvertToGCZ(BlobReader* infile, const std::string& infile_path,
                   const std::string& outfile_path, u32 sub_type, int block_size,
                   CompressCB callback)
 {
-  ASSERT(infile->IsDataSizeAccurate());
+  ASSERT(infile->GetDataSizeType() == DataSizeType::Accurate);
 
   File::IOFile outfile(outfile_path, "wb");
   if (!outfile)

Source/Core/DiscIO/CompressedBlob.h

@@ -53,7 +53,7 @@ public:
 
   u64 GetRawSize() const override { return m_file_size; }
   u64 GetDataSize() const override { return m_header.data_size; }
-  bool IsDataSizeAccurate() const override { return true; }
+  DataSizeType GetDataSizeType() const override { return DataSizeType::Accurate; }
 
   u64 GetBlockSize() const override { return m_header.block_size; }
   bool HasFastRandomAccessInBlock() const override { return false; }

Source/Core/DiscIO/DirectoryBlob.cpp

@@ -668,7 +668,7 @@ void DirectoryBlobReader::SetPartitions(std::vector<PartitionWithType>&& partiti
     m_partitions.emplace(partition_data_offset, std::move(partitions[i].partition));
     m_nonpartition_contents.Add(partition_data_offset, data_size,
                                 ContentPartition{this, 0, partition_data_offset});
-    const u64 unaligned_next_partition_address = VolumeWii::EncryptedPartitionOffsetToRawOffset(
+    const u64 unaligned_next_partition_address = VolumeWii::OffsetInHashedPartitionToRawOffset(
         data_size, Partition(partition_address), PARTITION_DATA_OFFSET);
     partition_address = Common::AlignUp(unaligned_next_partition_address, 0x10000ull);
   }
@@ -743,7 +743,7 @@ void DirectoryBlobReader::SetPartitionHeader(DirectoryBlobPartition* partition,
 
   if (wrapped_partition)
   {
-    if (m_wrapped_volume->IsEncryptedAndHashed())
+    if (m_wrapped_volume->HasWiiHashes())
     {
       const std::optional<u64> offset = m_wrapped_volume->ReadSwappedAndShifted(
           wrapped_partition->offset + WII_PARTITION_H3_OFFSET_ADDRESS, PARTITION_NONE);

Source/Core/DiscIO/DirectoryBlob.h

@@ -284,7 +284,7 @@ public:
 
   u64 GetRawSize() const override;
   u64 GetDataSize() const override;
-  bool IsDataSizeAccurate() const override { return true; }
+  DataSizeType GetDataSizeType() const override { return DataSizeType::Accurate; }
 
   u64 GetBlockSize() const override { return 0; }
   bool HasFastRandomAccessInBlock() const override { return true; }

Source/Core/DiscIO/DiscExtractor.cpp

@@ -286,7 +286,7 @@ bool ExportSystemData(const Volume& volume, const Partition& partition,
     success &= ExportTicket(volume, partition, export_folder + "/ticket.bin");
     success &= ExportTMD(volume, partition, export_folder + "/tmd.bin");
     success &= ExportCertificateChain(volume, partition, export_folder + "/cert.bin");
-    if (volume.IsEncryptedAndHashed())
+    if (volume.HasWiiHashes())
       success &= ExportH3Hashes(volume, partition, export_folder + "/h3.bin");
   }
 

Source/Core/DiscIO/DiscScrubber.cpp

@@ -30,7 +30,7 @@ bool DiscScrubber::SetupScrub(const Volume* disc)
     return false;
   m_disc = disc;
 
-  m_file_size = m_disc->GetSize();
+  m_file_size = m_disc->GetDataSize();
 
   // Round up when diving by CLUSTER_SIZE, otherwise MarkAsUsed might write out of bounds
   const size_t num_clusters = static_cast<size_t>((m_file_size + CLUSTER_SIZE - 1) / CLUSTER_SIZE);
@@ -47,7 +47,11 @@ bool DiscScrubber::SetupScrub(const Volume* disc)
 
 bool DiscScrubber::CanBlockBeScrubbed(u64 offset) const
 {
-  return m_is_scrubbing && m_free_table[offset / CLUSTER_SIZE];
+  if (!m_is_scrubbing)
+    return false;
+
+  const u64 cluster_index = offset / CLUSTER_SIZE;
+  return cluster_index >= m_free_table.size() || m_free_table[cluster_index];
 }
 
 void DiscScrubber::MarkAsUsed(u64 offset, u64 size)
@@ -92,7 +96,7 @@ void DiscScrubber::MarkAsUsedE(u64 partition_data_offset, u64 offset, u64 size)
 // Compensate for 0x400 (SHA-1) per 0x8000 (cluster), and round to whole clusters
 u64 DiscScrubber::ToClusterOffset(u64 offset) const
 {
-  if (m_disc->IsEncryptedAndHashed())
+  if (m_disc->HasWiiHashes())
     return offset / 0x7c00 * CLUSTER_SIZE;
   else
     return Common::AlignDown(offset, CLUSTER_SIZE);

Source/Core/DiscIO/DriveBlob.h

@@ -27,7 +27,7 @@ public:
 
   u64 GetRawSize() const override { return m_size; }
   u64 GetDataSize() const override { return m_size; }
-  bool IsDataSizeAccurate() const override { return true; }
+  DataSizeType GetDataSizeType() const override { return DataSizeType::Accurate; }
 
   u64 GetBlockSize() const override { return ECC_BLOCK_SIZE; }
   bool HasFastRandomAccessInBlock() const override { return false; }

Source/Core/DiscIO/FileBlob.cpp

@@ -44,7 +44,7 @@ bool PlainFileReader::Read(u64 offset, u64 nbytes, u8* out_ptr)
 bool ConvertToPlain(BlobReader* infile, const std::string& infile_path,
                     const std::string& outfile_path, CompressCB callback)
 {
-  ASSERT(infile->IsDataSizeAccurate());
+  ASSERT(infile->GetDataSizeType() == DataSizeType::Accurate);
 
   File::IOFile outfile(outfile_path, "wb");
   if (!outfile)

Source/Core/DiscIO/FileBlob.h

@@ -22,7 +22,7 @@ public:
 
   u64 GetRawSize() const override { return m_size; }
   u64 GetDataSize() const override { return m_size; }
-  bool IsDataSizeAccurate() const override { return true; }
+  DataSizeType GetDataSizeType() const override { return DataSizeType::Accurate; }
 
   u64 GetBlockSize() const override { return 0; }
   bool HasFastRandomAccessInBlock() const override { return true; }

Source/Core/DiscIO/NFSBlob.cpp

@@ -0,0 +1,306 @@
+// Copyright 2022 Dolphin Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include "DiscIO/NFSBlob.h"
+
+#include <algorithm>
+#include <array>
+#include <cstring>
+#include <memory>
+#include <string>
+#include <string_view>
+#include <utility>
+#include <vector>
+
+#include <fmt/format.h>
+
+#include "Common/Align.h"
+#include "Common/CommonTypes.h"
+#include "Common/Crypto/AES.h"
+#include "Common/IOFile.h"
+#include "Common/Logging/Log.h"
+#include "Common/StringUtil.h"
+#include "Common/Swap.h"
+
+namespace DiscIO
+{
+bool NFSFileReader::ReadKey(const std::string& path, const std::string& directory, Key* key_out)
+{
+  const std::string_view directory_without_trailing_slash =
+      std::string_view(directory).substr(0, directory.size() - 1);
+
+  std::string parent, parent_name, parent_extension;
+  SplitPath(directory_without_trailing_slash, &parent, &parent_name, &parent_extension);
+
+  if (parent_name + parent_extension != "content")
+  {
+    ERROR_LOG_FMT(DISCIO, "hif_000000.nfs is not in a directory named 'content': {}", path);
+    return false;
+  }
+
+  const std::string key_path = parent + "code/htk.bin";
+  File::IOFile key_file(key_path, "rb");
+  if (!key_file.ReadBytes(key_out->data(), key_out->size()))
+  {
+    ERROR_LOG_FMT(DISCIO, "Failed to read from {}", key_path);
+    return false;
+  }
+
+  return true;
+}
+
+std::vector<NFSLBARange> NFSFileReader::GetLBARanges(const NFSHeader& header)
+{
+  const size_t lba_range_count =
+      std::min<size_t>(Common::swap32(header.lba_range_count), header.lba_ranges.size());
+
+  std::vector<NFSLBARange> lba_ranges;
+  lba_ranges.reserve(lba_range_count);
+
+  for (size_t i = 0; i < lba_range_count; ++i)
+  {
+    const NFSLBARange& unswapped_lba_range = header.lba_ranges[i];
+    lba_ranges.push_back(NFSLBARange{Common::swap32(unswapped_lba_range.start_block),
+                                     Common::swap32(unswapped_lba_range.num_blocks)});
+  }
+
+  return lba_ranges;
+}
+
+std::vector<File::IOFile> NFSFileReader::OpenFiles(const std::string& directory,
+                                                   File::IOFile first_file, u64 expected_raw_size,
+                                                   u64* raw_size_out)
+{
+  const u64 file_count = Common::AlignUp(expected_raw_size, MAX_FILE_SIZE) / MAX_FILE_SIZE;
+
+  std::vector<File::IOFile> files;
+  files.reserve(file_count);
+
+  u64 raw_size = first_file.GetSize();
+  files.emplace_back(std::move(first_file));
+
+  for (u64 i = 1; i < file_count; ++i)
+  {
+    const std::string child_path = fmt::format("{}hif_{:06}.nfs", directory, i);
+    File::IOFile child(child_path, "rb");
+    if (!child)
+    {
+      ERROR_LOG_FMT(DISCIO, "Failed to open {}", child_path);
+      return {};
+    }
+
+    raw_size += child.GetSize();
+    files.emplace_back(std::move(child));
+  }
+
+  if (raw_size < expected_raw_size)
+  {
+    ERROR_LOG_FMT(
+        DISCIO,
+        "Expected sum of NFS file sizes for {} to be at least {} bytes, but it was {} bytes",
+        directory, expected_raw_size, raw_size);
+    return {};
+  }
+
+  return files;
+}
+
+u64 NFSFileReader::CalculateExpectedRawSize(const std::vector<NFSLBARange>& lba_ranges)
+{
+  u64 total_blocks = 0;
+  for (const NFSLBARange& range : lba_ranges)
+    total_blocks += range.num_blocks;
+
+  return sizeof(NFSHeader) + total_blocks * BLOCK_SIZE;
+}
+
+u64 NFSFileReader::CalculateExpectedDataSize(const std::vector<NFSLBARange>& lba_ranges)
+{
+  u32 greatest_block_index = 0;
+  for (const NFSLBARange& range : lba_ranges)
+    greatest_block_index = std::max(greatest_block_index, range.start_block + range.num_blocks);
+
+  return u64(greatest_block_index) * BLOCK_SIZE;
+}
+
+std::unique_ptr<NFSFileReader> NFSFileReader::Create(File::IOFile first_file,
+                                                     const std::string& path)
+{
+  std::string directory, filename, extension;
+  SplitPath(path, &directory, &filename, &extension);
+  if (filename + extension != "hif_000000.nfs")
+    return nullptr;
+
+  std::array<u8, 16> key;
+  if (!ReadKey(path, directory, &key))
+    return nullptr;
+
+  NFSHeader header;
+  if (!first_file.Seek(0, File::SeekOrigin::Begin) ||
+      !first_file.ReadArray(&header, 1) && header.magic != NFS_MAGIC)
+  {
+    return nullptr;
+  }
+
+  std::vector<NFSLBARange> lba_ranges = GetLBARanges(header);
+
+  const u64 expected_raw_size = CalculateExpectedRawSize(lba_ranges);
+
+  u64 raw_size;
+  std::vector<File::IOFile> files =
+      OpenFiles(directory, std::move(first_file), expected_raw_size, &raw_size);
+
+  if (files.empty())
+    return nullptr;
+
+  return std::unique_ptr<NFSFileReader>(
+      new NFSFileReader(std::move(lba_ranges), std::move(files), key, raw_size));
+}
+
+NFSFileReader::NFSFileReader(std::vector<NFSLBARange> lba_ranges, std::vector<File::IOFile> files,
+                             Key key, u64 raw_size)
+    : m_lba_ranges(std::move(lba_ranges)), m_files(std::move(files)),
+      m_aes_context(Common::AES::CreateContextDecrypt(key.data())), m_raw_size(raw_size)
+{
+  m_data_size = CalculateExpectedDataSize(m_lba_ranges);
+}
+
+u64 NFSFileReader::GetDataSize() const
+{
+  return m_data_size;
+}
+
+u64 NFSFileReader::GetRawSize() const
+{
+  return m_raw_size;
+}
+
+u64 NFSFileReader::ToPhysicalBlockIndex(u64 logical_block_index)
+{
+  u64 physical_blocks_so_far = 0;
+
+  for (const NFSLBARange& range : m_lba_ranges)
+  {
+    if (logical_block_index >= range.start_block &&
+        logical_block_index < range.start_block + range.num_blocks)
+    {
+      return physical_blocks_so_far + (logical_block_index - range.start_block);
+    }
+
+    physical_blocks_so_far += range.num_blocks;
+  }
+
+  return std::numeric_limits<u64>::max();
+}
+
+bool NFSFileReader::ReadEncryptedBlock(u64 physical_block_index)
+{
+  constexpr u64 BLOCKS_PER_FILE = MAX_FILE_SIZE / BLOCK_SIZE;
+
+  const u64 file_index = physical_block_index / BLOCKS_PER_FILE;
+  const u64 block_in_file = physical_block_index % BLOCKS_PER_FILE;
+
+  if (block_in_file == BLOCKS_PER_FILE - 1)
+  {
+    // Special case. Because of the 0x200 byte header at the very beginning,
+    // the last block of each file has its last 0x200 bytes stored in the next file.
+
+    constexpr size_t PART_1_SIZE = BLOCK_SIZE - sizeof(NFSHeader);
+    constexpr size_t PART_2_SIZE = sizeof(NFSHeader);
+
+    File::IOFile& file_1 = m_files[file_index];
+    File::IOFile& file_2 = m_files[file_index + 1];
+
+    if (!file_1.Seek(sizeof(NFSHeader) + block_in_file * BLOCK_SIZE, File::SeekOrigin::Begin) ||
+        !file_1.ReadBytes(m_current_block_encrypted.data(), PART_1_SIZE))
+    {
+      file_1.ClearError();
+      return false;
+    }
+
+    if (!file_2.Seek(0, File::SeekOrigin::Begin) ||
+        !file_2.ReadBytes(m_current_block_encrypted.data() + PART_1_SIZE, PART_2_SIZE))
+    {
+      file_2.ClearError();
+      return false;
+    }
+  }
+  else
+  {
+    // Normal case. The read is offset by 0x200 bytes, but it's all within one file.
+
+    File::IOFile& file = m_files[file_index];
+
+    if (!file.Seek(sizeof(NFSHeader) + block_in_file * BLOCK_SIZE, File::SeekOrigin::Begin) ||
+        !file.ReadBytes(m_current_block_encrypted.data(), BLOCK_SIZE))
+    {
+      file.ClearError();
+      return false;
+    }
+  }
+
+  return true;
+}
+
+void NFSFileReader::DecryptBlock(u64 logical_block_index)
+{
+  std::array<u8, 16> iv{};
+  const u64 swapped_block_index = Common::swap64(logical_block_index);
+  std::memcpy(iv.data() + iv.size() - sizeof(swapped_block_index), &swapped_block_index,
+              sizeof(swapped_block_index));
+
+  m_aes_context->Crypt(iv.data(), m_current_block_encrypted.data(),
+                       m_current_block_decrypted.data(), BLOCK_SIZE);
+}
+
+bool NFSFileReader::ReadAndDecryptBlock(u64 logical_block_index)
+{
+  const u64 physical_block_index = ToPhysicalBlockIndex(logical_block_index);
+
+  if (physical_block_index == std::numeric_limits<u64>::max())
+  {
+    // The block isn't physically present. Treat its contents as all zeroes.
+    m_current_block_decrypted.fill(0);
+  }
+  else
+  {
+    if (!ReadEncryptedBlock(physical_block_index))
+      return false;
+
+    DecryptBlock(logical_block_index);
+  }
+
+  // Small hack: Set 0x61 of the header to 1 so that VolumeWii realizes that the disc is unencrypted
+  if (logical_block_index == 0)
+    m_current_block_decrypted[0x61] = 1;
+
+  return true;
+}
+
+bool NFSFileReader::Read(u64 offset, u64 nbytes, u8* out_ptr)
+{
+  while (nbytes != 0)
+  {
+    const u64 logical_block_index = offset / BLOCK_SIZE;
+    const u64 offset_in_block = offset % BLOCK_SIZE;
+
+    if (logical_block_index != m_current_logical_block_index)
+    {
+      if (!ReadAndDecryptBlock(logical_block_index))
+        return false;
+
+      m_current_logical_block_index = logical_block_index;
+    }
+
+    const u64 bytes_to_copy = std::min(nbytes, BLOCK_SIZE - offset_in_block);
+    std::memcpy(out_ptr, m_current_block_decrypted.data() + offset_in_block, bytes_to_copy);
+
+    offset += bytes_to_copy;
+    nbytes -= bytes_to_copy;
+    out_ptr += bytes_to_copy;
+  }
+
+  return true;
+}
+
+}  // namespace DiscIO

Source/Core/DiscIO/NFSBlob.h

@@ -0,0 +1,91 @@
+// Copyright 2022 Dolphin Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include <array>
+#include <limits>
+#include <memory>
+#include <string>
+#include <vector>
+
+#include "Common/CommonTypes.h"
+#include "Common/Crypto/AES.h"
+#include "Common/IOFile.h"
+#include "DiscIO/Blob.h"
+
+// This is the file format used for Wii games released on the Wii U eShop.
+
+namespace DiscIO
+{
+static constexpr u32 NFS_MAGIC = 0x53474745;  // "EGGS" (byteswapped to little endian)
+
+struct NFSLBARange
+{
+  u32 start_block;
+  u32 num_blocks;
+};
+
+struct NFSHeader
+{
+  u32 magic;  // EGGS
+  u32 version;
+  u32 unknown_1;
+  u32 unknown_2;
+  u32 lba_range_count;
+  std::array<NFSLBARange, 61> lba_ranges;
+  u32 end_magic;  // SGGE
+};
+static_assert(sizeof(NFSHeader) == 0x200);
+
+class NFSFileReader : public BlobReader
+{
+public:
+  static std::unique_ptr<NFSFileReader> Create(File::IOFile first_file,
+                                               const std::string& directory_path);
+
+  BlobType GetBlobType() const override { return BlobType::NFS; }
+
+  u64 GetRawSize() const override;
+  u64 GetDataSize() const override;
+  DataSizeType GetDataSizeType() const override { return DataSizeType::LowerBound; }
+
+  u64 GetBlockSize() const override { return BLOCK_SIZE; }
+  bool HasFastRandomAccessInBlock() const override { return false; }
+  std::string GetCompressionMethod() const override { return {}; }
+  std::optional<int> GetCompressionLevel() const override { return std::nullopt; }
+
+  bool Read(u64 offset, u64 nbytes, u8* out_ptr) override;
+
+private:
+  using Key = std::array<u8, Common::AES::Context::KEY_SIZE>;
+  static constexpr u32 BLOCK_SIZE = 0x8000;
+  static constexpr u32 MAX_FILE_SIZE = 0xFA00000;
+
+  static bool ReadKey(const std::string& path, const std::string& directory, Key* key_out);
+  static std::vector<NFSLBARange> GetLBARanges(const NFSHeader& header);
+  static std::vector<File::IOFile> OpenFiles(const std::string& directory, File::IOFile first_file,
+                                             u64 expected_raw_size, u64* raw_size_out);
+  static u64 CalculateExpectedRawSize(const std::vector<NFSLBARange>& lba_ranges);
+  static u64 CalculateExpectedDataSize(const std::vector<NFSLBARange>& lba_ranges);
+
+  NFSFileReader(std::vector<NFSLBARange> lba_ranges, std::vector<File::IOFile> files, Key key,
+                u64 raw_size);
+
+  u64 ToPhysicalBlockIndex(u64 logical_block_index);
+  bool ReadEncryptedBlock(u64 physical_block_index);
+  void DecryptBlock(u64 logical_block_index);
+  bool ReadAndDecryptBlock(u64 logical_block_index);
+
+  std::array<u8, BLOCK_SIZE> m_current_block_encrypted;
+  std::array<u8, BLOCK_SIZE> m_current_block_decrypted;
+  u64 m_current_logical_block_index = std::numeric_limits<u64>::max();
+
+  std::vector<NFSLBARange> m_lba_ranges;
+  std::vector<File::IOFile> m_files;
+  std::unique_ptr<Common::AES::Context> m_aes_context;
+  u64 m_raw_size;
+  u64 m_data_size;
+};
+
+}  // namespace DiscIO