GCMemcard: Read file comments according to logical data offsets instead of physical data offsets.

3 files changed, 36 insertions, 49 deletions

diff --git a/Source/Core/Core/HW/GCMemcard/GCMemcard.cpp b/Source/Core/Core/HW/GCMemcard/GCMemcard.cpp
index 33c6c58858..07dcb01b69 100644
--- a/Source/Core/Core/HW/GCMemcard/GCMemcard.cpp
+++ b/Source/Core/Core/HW/GCMemcard/GCMemcard.cpp
@@ -639,43 +639,33 @@ std::optional<std::vector<u8>> GCMemcard::GetSaveDataBytes(u8 save_index, size_t
   return std::make_optional(std::move(result));
 }
 
-u32 GCMemcard::DEntry_CommentsAddress(u8 index) const
+std::optional<std::pair<std::string, std::string>> GCMemcard::GetSaveComments(u8 index) const
 {
   if (!m_valid || index >= DIRLEN)
-    return 0xFFFF;
-
-  return GetActiveDirectory().m_dir_entries[index].m_comments_address;
-}
-
-std::string GCMemcard::GetSaveComment1(u8 index) const
-{
-  if (!m_valid || index >= DIRLEN)
-    return "";
+    return std::nullopt;
 
-  u32 Comment1 = GetActiveDirectory().m_dir_entries[index].m_comments_address;
-  u32 DataBlock = GetActiveDirectory().m_dir_entries[index].m_first_block - MC_FST_BLOCKS;
-  if ((DataBlock > m_size_blocks) || (Comment1 == 0xFFFFFFFF))
-  {
-    return "";
-  }
-  return std::string((const char*)m_data_blocks[DataBlock].m_block.data() + Comment1,
-                     DENTRY_STRLEN);
-}
+  const u32 address = GetActiveDirectory().m_dir_entries[index].m_comments_address;
+  if (address == 0xFFFFFFFF)
+    return std::nullopt;
 
-std::string GCMemcard::GetSaveComment2(u8 index) const
-{
-  if (!m_valid || index >= DIRLEN)
-    return "";
+  const auto data = GetSaveDataBytes(index, address, DENTRY_STRLEN * 2);
+  if (!data || data->size() != DENTRY_STRLEN * 2)
+    return std::nullopt;
 
-  u32 Comment1 = GetActiveDirectory().m_dir_entries[index].m_comments_address;
-  u32 Comment2 = Comment1 + DENTRY_STRLEN;
-  u32 DataBlock = GetActiveDirectory().m_dir_entries[index].m_first_block - MC_FST_BLOCKS;
-  if ((DataBlock > m_size_blocks) || (Comment1 == 0xFFFFFFFF))
-  {
-    return "";
-  }
-  return std::string((const char*)m_data_blocks[DataBlock].m_block.data() + Comment2,
-                     DENTRY_STRLEN);
+  const auto string_decoder = IsShiftJIS() ? SHIFTJISToUTF8 : CP1252ToUTF8;
+  const auto strip_null = [](const std::string& s) {
+    auto offset = s.find('\0');
+    if (offset == std::string::npos)
+      offset = s.length();
+    return s.substr(0, offset);
+  };
+
+  const u8* address_1 = data->data();
+  const u8* address_2 = address_1 + DENTRY_STRLEN;
+  const std::string encoded_1(reinterpret_cast<const char*>(address_1), DENTRY_STRLEN);
+  const std::string encoded_2(reinterpret_cast<const char*>(address_2), DENTRY_STRLEN);
+  return std::make_pair(strip_null(string_decoder(encoded_1)),
+                        strip_null(string_decoder(encoded_2)));
 }
 
 std::optional<DEntry> GCMemcard::GetDEntry(u8 index) const
diff --git a/Source/Core/Core/HW/GCMemcard/GCMemcard.h b/Source/Core/Core/HW/GCMemcard/GCMemcard.h
index d8c7b79486..24db3194ea 100644
--- a/Source/Core/Core/HW/GCMemcard/GCMemcard.h
+++ b/Source/Core/Core/HW/GCMemcard/GCMemcard.h
@@ -118,7 +118,7 @@ constexpr u32 MC_FST_BLOCKS = 0x05;
 // maximum number of saves that can be stored on a single memory card
 constexpr u8 DIRLEN = 0x7F;
 
-// maximum size of memory card file comment in bytes
+// maximum size of a single memory card file comment in bytes
 constexpr u32 DENTRY_STRLEN = 0x20;
 
 // size of a single entry in the Directory in bytes
@@ -456,9 +456,10 @@ public:
   GetSaveDataBytes(u8 save_index, size_t offset = 0,
                    size_t length = std::numeric_limits<size_t>::max()) const;
 
-  u32 DEntry_CommentsAddress(u8 index) const;
-  std::string GetSaveComment1(u8 index) const;
-  std::string GetSaveComment2(u8 index) const;
+  // Returns, if available, the two strings shown on the save file in the GC BIOS, in UTF8.
+  // The first is the big line on top, usually the game title, and the second is the smaller line
+  // next to the block size, often a progress indicator or subtitle.
+  std::optional<std::pair<std::string, std::string>> GetSaveComments(u8 index) const;
 
   // Fetches a DEntry from the given file index.
   std::optional<DEntry> GetDEntry(u8 index) const;
diff --git a/Source/Core/DolphinQt/GCMemcardManager.cpp b/Source/Core/DolphinQt/GCMemcardManager.cpp
index 84dc10d02b..17d5d162e3 100644
--- a/Source/Core/DolphinQt/GCMemcardManager.cpp
+++ b/Source/Core/DolphinQt/GCMemcardManager.cpp
@@ -186,14 +186,6 @@ void GCMemcardManager::UpdateSlotTable(int slot)
     return item;
   };
 
-  const auto strip_garbage = [](const std::string& s) {
-    auto offset = s.find('\0');
-    if (offset == std::string::npos)
-      offset = s.length();
-
-    return s.substr(0, offset);
-  };
-
   const u8 num_files = memcard->GetNumFiles();
   m_slot_active_icons[slot].reserve(num_files);
   for (int i = 0; i < num_files; i++)
@@ -201,12 +193,16 @@ void GCMemcardManager::UpdateSlotTable(int slot)
     int file_index = memcard->GetFileIndex(i);
     table->setRowCount(i + 1);
 
-    auto const string_decoder = memcard->IsShiftJIS() ? SHIFTJISToUTF8 : CP1252ToUTF8;
+    const auto file_comments = memcard->GetSaveComments(file_index);
+
+    QString title;
+    QString comment;
+    if (file_comments)
+    {
+      title = QString::fromStdString(file_comments->first);
+      comment = QString::fromStdString(file_comments->second);
+    }
 
-    QString title =
-        QString::fromStdString(strip_garbage(string_decoder(memcard->GetSaveComment1(file_index))));
-    QString comment =
-        QString::fromStdString(strip_garbage(string_decoder(memcard->GetSaveComment2(file_index))));
     QString blocks = QStringLiteral("%1").arg(memcard->DEntry_BlockCount(file_index));
     QString block_count = QStringLiteral("%1").arg(memcard->DEntry_FirstBlock(file_index));