fs: Fix RomFS building when zero byte files are present

When zero byte files are present, the key (offset) for that file is identical to the file right after. A std::map isn't able to fit key-value pairs with identical keys (offsets), therefore, the solution is to use std::multimap which permits multiple entries with the same key.

This most prominently fixes Pokemon Sword and Shield weather with any RomFS mod applied.

1 files changed, 3 insertions, 3 deletions

diff --git a/src/core/file_sys/vfs_concat.h b/src/core/file_sys/vfs_concat.h
index c90f9d5d1..7a26343c0 100644
--- a/src/core/file_sys/vfs_concat.h
+++ b/src/core/file_sys/vfs_concat.h
@@ -15,7 +15,7 @@ namespace FileSys {
 // read-only.
 class ConcatenatedVfsFile : public VfsFile {
     ConcatenatedVfsFile(std::vector<VirtualFile> files, std::string name);
-    ConcatenatedVfsFile(std::map<u64, VirtualFile> files, std::string name);
+    ConcatenatedVfsFile(std::multimap<u64, VirtualFile> files, std::string name);
 
 public:
     ~ConcatenatedVfsFile() override;
@@ -25,7 +25,7 @@ public:
 
     /// Convenience function that turns a map of offsets to files into a concatenated file, filling
     /// gaps with a given filler byte.
-    static VirtualFile MakeConcatenatedFile(u8 filler_byte, std::map<u64, VirtualFile> files,
+    static VirtualFile MakeConcatenatedFile(u8 filler_byte, std::multimap<u64, VirtualFile> files,
                                             std::string name);
 
     std::string GetName() const override;
@@ -40,7 +40,7 @@ public:
 
 private:
     // Maps starting offset to file -- more efficient.
-    std::map<u64, VirtualFile> files;
+    std::multimap<u64, VirtualFile> files;
     std::string name;
 };