From 319c50897881c7ee1aba8e0bfe396cb385d9eb37 Mon Sep 17 00:00:00 2001
From: JosJuice <josjuice@gmail.com>
Date: Thu, 23 Jan 2020 16:47:49 +0100
Subject: DiscIO: Implement re-encryption of Wii partition data

---
 Source/Core/DiscIO/WiiEncryptionCache.cpp | 80 +++++++++++++++++++++++++++++++
 1 file changed, 80 insertions(+)
 create mode 100644 Source/Core/DiscIO/WiiEncryptionCache.cpp

(limited to 'Source/Core/DiscIO/WiiEncryptionCache.cpp')

diff --git a/Source/Core/DiscIO/WiiEncryptionCache.cpp b/Source/Core/DiscIO/WiiEncryptionCache.cpp
new file mode 100644
index 0000000000..c5a2111daa
--- /dev/null
+++ b/Source/Core/DiscIO/WiiEncryptionCache.cpp
@@ -0,0 +1,80 @@
+// Copyright 2020 Dolphin Emulator Project
+// Licensed under GPLv2+
+// Refer to the license.txt file included.
+
+#include "DiscIO/WiiEncryptionCache.h"
+
+#include <array>
+#include <cstring>
+#include <limits>
+#include <memory>
+
+#include "Common/Align.h"
+#include "Common/CommonTypes.h"
+#include "DiscIO/Blob.h"
+#include "DiscIO/VolumeWii.h"
+
+namespace DiscIO
+{
+WiiEncryptionCache::WiiEncryptionCache(BlobReader* blob) : m_blob(blob)
+{
+}
+
+WiiEncryptionCache::~WiiEncryptionCache() = default;
+
+const std::array<u8, VolumeWii::GROUP_TOTAL_SIZE>*
+WiiEncryptionCache::EncryptGroup(u64 offset, u64 partition_data_offset,
+                                 u64 partition_data_decrypted_size, const Key& key)
+{
+  // Only allocate memory if this function actually ends up getting called
+  if (!m_cache)
+  {
+    m_cache = std::make_unique<std::array<u8, VolumeWii::GROUP_TOTAL_SIZE>>();
+    ASSERT(m_blob->SupportsReadWiiDecrypted());
+  }
+
+  ASSERT(offset % VolumeWii::GROUP_TOTAL_SIZE == 0);
+  const u64 group_offset_in_partition =
+      offset / VolumeWii::GROUP_TOTAL_SIZE * VolumeWii::GROUP_DATA_SIZE;
+  const u64 group_offset_on_disc = partition_data_offset + offset;
+
+  if (m_cached_offset != group_offset_on_disc)
+  {
+    if (!VolumeWii::EncryptGroup(group_offset_in_partition, partition_data_offset,
+                                 partition_data_decrypted_size, key, m_blob, m_cache.get()))
+    {
+      m_cached_offset = std::numeric_limits<u64>::max();  // Invalidate the cache
+      return nullptr;
+    }
+
+    m_cached_offset = group_offset_on_disc;
+  }
+
+  return m_cache.get();
+}
+
+bool WiiEncryptionCache::EncryptGroups(u64 offset, u64 size, u8* out_ptr, u64 partition_data_offset,
+                                       u64 partition_data_decrypted_size, const Key& key)
+{
+  while (size > 0)
+  {
+    const std::array<u8, VolumeWii::GROUP_TOTAL_SIZE>* group =
+        EncryptGroup(Common::AlignDown(offset, VolumeWii::GROUP_TOTAL_SIZE), partition_data_offset,
+                     partition_data_decrypted_size, key);
+
+    if (!group)
+      return false;
+
+    const u64 offset_in_group = offset % VolumeWii::GROUP_TOTAL_SIZE;
+    const u64 bytes_to_read = std::min(VolumeWii::GROUP_TOTAL_SIZE - offset_in_group, size);
+    std::memcpy(out_ptr, group->data() + offset_in_group, bytes_to_read);
+
+    offset += bytes_to_read;
+    size -= bytes_to_read;
+    out_ptr += bytes_to_read;
+  }
+
+  return true;
+}
+
+}  // namespace DiscIO
-- 
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