From 733284cc168c16dd52d6772432659ea78f3f545c Mon Sep 17 00:00:00 2001
From: Peter Nelson <peter1138@openttd.org>
Date: Sun, 10 Mar 2024 11:24:03 +0000
Subject: [PATCH] Codechange: Return std::vector from GetMusicCatEntryData.

Return std::vector instead of pointer to array with manual memory management.
---
 src/base_media_base.h  |  2 +-
 src/music.cpp          | 31 ++++++++++++++-----------------
 src/music/midifile.cpp | 18 ++++++------------
 3 files changed, 21 insertions(+), 30 deletions(-)

diff --git a/src/base_media_base.h b/src/base_media_base.h
index a9a70c2278..0bd288a9a2 100644
--- a/src/base_media_base.h
+++ b/src/base_media_base.h
@@ -314,7 +314,7 @@ static const uint NUM_SONGS_PLAYLIST  = 32;
 
 /* Functions to read DOS music CAT files, similar to but not quite the same as sound effect CAT files */
 std::optional<std::string> GetMusicCatEntryName(const std::string &filename, size_t entrynum);
-uint8_t *GetMusicCatEntryData(const std::string &filename, size_t entrynum, size_t &entrylen);
+std::optional<std::vector<uint8_t>> GetMusicCatEntryData(const std::string &filename, size_t entrynum);
 
 enum MusicTrackType {
 	MTT_STANDARDMIDI, ///< Standard MIDI file
diff --git a/src/music.cpp b/src/music.cpp
index 1974ee261b..52a8ef259c 100644
--- a/src/music.cpp
+++ b/src/music.cpp
@@ -47,29 +47,26 @@ std::optional<std::string> GetMusicCatEntryName(const std::string &filename, siz
  * Read the full data of a music CAT file entry.
  * @param filename Name of CAT file to read from.
  * @param entrynum Index of entry to read
- * @param[out] entrylen Receives length of data read
- * @return Pointer to buffer with data read, caller is responsible for freeind memory,
- *         nullptr if entrynum does not exist.
+ * @return Data of CAT file entry.
  */
-uint8_t *GetMusicCatEntryData(const std::string &filename, size_t entrynum, size_t &entrylen)
+std::optional<std::vector<uint8_t>> GetMusicCatEntryData(const std::string &filename, size_t entrynum)
 {
-	entrylen = 0;
-	if (!FioCheckFileExists(filename, BASESET_DIR)) return nullptr;
+	if (!FioCheckFileExists(filename, BASESET_DIR)) return std::nullopt;
 
 	RandomAccessFile file(filename, BASESET_DIR);
 	uint32_t ofs = file.ReadDword();
 	size_t entry_count = ofs / 8;
-	if (entrynum < entry_count) {
-		file.SeekTo(entrynum * 8, SEEK_SET);
-		size_t entrypos = file.ReadDword();
-		entrylen = file.ReadDword();
-		file.SeekTo(entrypos, SEEK_SET);
-		file.SkipBytes(file.ReadByte());
-		uint8_t *data = MallocT<uint8_t>(entrylen);
-		file.ReadBlock(data, entrylen);
-		return data;
-	}
-	return nullptr;
+	if (entrynum >= entry_count) return std::nullopt;
+
+	file.SeekTo(entrynum * 8, SEEK_SET);
+	size_t entrypos = file.ReadDword();
+	size_t entrylen = file.ReadDword();
+	file.SeekTo(entrypos, SEEK_SET);
+	file.SkipBytes(file.ReadByte());
+
+	std::vector<uint8_t> data(entrylen);
+	file.ReadBlock(data.data(), entrylen);
+	return data;
 }
 
 INSTANTIATE_BASE_MEDIA_METHODS(BaseMedia<MusicSet>, MusicSet)
diff --git a/src/music/midifile.cpp b/src/music/midifile.cpp
index ece0046c8d..a5eddd6278 100644
--- a/src/music/midifile.cpp
+++ b/src/music/midifile.cpp
@@ -843,11 +843,9 @@ bool MidiFile::LoadSong(const MusicSongInfo &song)
 			return this->LoadFile(song.filename);
 		case MTT_MPSMIDI:
 		{
-			size_t songdatalen = 0;
-			uint8_t *songdata = GetMusicCatEntryData(song.filename, song.cat_index, songdatalen);
-			if (songdata != nullptr) {
-				bool result = this->LoadMpsData(songdata, songdatalen);
-				free(songdata);
+			auto songdata = GetMusicCatEntryData(song.filename, song.cat_index);
+			if (songdata.has_value()) {
+				bool result = this->LoadMpsData(songdata->data(), songdata->size());
 				return result;
 			} else {
 				return false;
@@ -1078,17 +1076,13 @@ std::string MidiFile::GetSMFFile(const MusicSongInfo &song)
 		return output_filename;
 	}
 
-	uint8_t *data;
-	size_t datalen;
-	data = GetMusicCatEntryData(song.filename, song.cat_index, datalen);
-	if (data == nullptr) return std::string();
+	auto songdata = GetMusicCatEntryData(song.filename, song.cat_index);
+	if (!songdata.has_value()) return std::string();
 
 	MidiFile midifile;
-	if (!midifile.LoadMpsData(data, datalen)) {
-		free(data);
+	if (!midifile.LoadMpsData(songdata->data(), songdata->size())) {
 		return std::string();
 	}
-	free(data);
 
 	if (midifile.WriteSMF(output_filename)) {
 		return output_filename;