tag/Id3Load, ...: use std::make_unique_for_overwrite()

Don't zero-initialize the buffers.  This removes some useless
overhead.

Author: MaxKellermann

src/command/FileCommands.cxx

@@ -191,7 +191,7 @@ read_stream_art(Response &r, const std::string_view art_directory,
 		std::min<offset_type>(art_file_size - offset,
 				      r.GetClient().binary_limit);
 
-	auto buffer = std::make_unique<std::byte[]>(buffer_size);
+	auto buffer = std::make_unique_for_overwrite<std::byte[]>(buffer_size);
 
 	std::size_t read_size = 0;
 	if (buffer_size > 0) {

src/decoder/plugins/MadDecoderPlugin.cxx

@@ -266,7 +266,7 @@ MadDecoder::ParseId3(size_t tagsize, Tag *mpd_tag) noexcept
 		id3_data = stream.this_frame;
 		mad_stream_skip(&(stream), tagsize);
 	} else {
-		allocated = std::make_unique<id3_byte_t[]>(tagsize);
+		allocated = std::make_unique_for_overwrite<id3_byte_t[]>(tagsize);
 		memcpy(allocated.get(), stream.this_frame, count);
 		mad_stream_skip(&(stream), count);
 

src/decoder/plugins/SidplayDecoderPlugin.cxx

@@ -101,15 +101,15 @@ SidplayGlobal::SidplayGlobal(const ConfigBlock &block)
 	const auto kernal_path = block.GetPath("kernal");
 	if (!kernal_path.IsNull())
 	{
-		kernal = std::make_unique<uint8_t[]>(rom_size);
+		kernal = std::make_unique_for_overwrite<uint8_t[]>(rom_size);
 		loadRom(kernal_path, kernal.get());
 	}
 
 	/* read basic rom dump file */
 	const auto basic_path = block.GetPath("basic");
 	if (!basic_path.IsNull())
 	{
-		basic = std::make_unique<uint8_t[]>(rom_size);
+		basic = std::make_unique_for_overwrite<uint8_t[]>(rom_size);
 		loadRom(basic_path, basic.get());
 	}
 }

src/io/uring/ReadOperation.cxx

@@ -17,7 +17,7 @@ ReadOperation::Start(Queue &queue, FileDescriptor fd, off_t offset,
 
 	handler = &_handler;
 
-	buffer = std::make_unique<std::byte[]>(size);
+	buffer = std::make_unique_for_overwrite<std::byte[]>(size);
 
 	auto &s = queue.RequireSubmitEntry();
 

src/lib/icu/Util.cxx

@@ -38,7 +38,7 @@ UCharToUTF8(std::basic_string_view<UChar> src)
 	/* worst-case estimate */
 	size_t dest_capacity = 4 * src.size();
 
-	auto dest = std::make_unique<char[]>(dest_capacity + 1);
+	auto dest = std::make_unique_for_overwrite<char[]>(dest_capacity + 1);
 
 	UErrorCode error_code = U_ZERO_ERROR;
 	int32_t dest_length;

src/lib/icu/Win32.cxx

@@ -18,7 +18,7 @@ WideCharToMultiByte(unsigned code_page, std::wstring_view src)
 	if (length <= 0)
 		throw MakeLastError("Failed to convert from Unicode");
 
-	auto buffer = std::make_unique<char[]>(length + 1);
+	auto buffer = std::make_unique_for_overwrite<char[]>(length + 1);
 	length = WideCharToMultiByte(code_page, 0, src.data(), src.size(),
 				     buffer.get(), length,
 				     nullptr, nullptr);
@@ -37,7 +37,7 @@ MultiByteToWideChar(unsigned code_page, std::string_view src)
 	if (length <= 0)
 		throw MakeLastError("Failed to convert to Unicode");
 
-	auto buffer = std::make_unique<wchar_t[]>(length + 1);
+	auto buffer = std::make_unique_for_overwrite<wchar_t[]>(length + 1);
 	length = MultiByteToWideChar(code_page, 0, src.data(), src.size(),
 				     buffer.get(), length);
 	if (length <= 0)

src/lib/nfs/FileReader.cxx

@@ -148,7 +148,7 @@ NfsFileReader::Read(uint64_t offset, size_t size)
 #ifdef LIBNFS_API_2
 	assert(!read_buffer);
 	// TOOD read into caller-provided buffer
-	read_buffer = std::make_unique<std::byte[]>(size);
+	read_buffer = std::make_unique_for_overwrite<std::byte[]>(size);
 	connection->Read(fh, offset, {read_buffer.get(), size}, *this);
 #else
 	connection->Read(fh, offset, size, *this);

src/queue/Queue.cxx

@@ -147,7 +147,7 @@ Queue::MovePostion(unsigned from, unsigned to) noexcept
 void
 Queue::MoveRange(unsigned start, unsigned end, unsigned to) noexcept
 {
-	const auto tmp = std::make_unique<Item[]>(end - start);
+	const auto tmp = std::make_unique_for_overwrite<Item[]>(end - start);
 
 	// Copy the original block [start,end-1]
 	for (unsigned i = start; i < end; i++)

src/tag/ApeLoader.cxx

@@ -50,7 +50,7 @@ try {
 	remaining -= sizeof(footer);
 	assert(remaining > 10);
 
-	auto buffer = std::make_unique<std::byte[]>(remaining);
+	auto buffer = std::make_unique_for_overwrite<std::byte[]>(remaining);
 	is.ReadFull(lock, {buffer.get(), remaining});
 
 	/* read tags */

src/tag/Id3Load.cxx

@@ -47,7 +47,7 @@ try {
 		/* we have enough data already */
 		return UniqueId3Tag(id3_tag_parse(query_buffer, tag_size));
 
-	auto tag_buffer = std::make_unique<id3_byte_t[]>(tag_size);
+	auto tag_buffer = std::make_unique_for_overwrite<id3_byte_t[]>(tag_size);
 
 	/* copy the start of the tag we already have to the allocated
 	   buffer */
@@ -182,7 +182,7 @@ try {
 		/* too large, don't allocate so much memory */
 		return nullptr;
 
-	auto buffer = std::make_unique<id3_byte_t[]>(size);
+	auto buffer = std::make_unique_for_overwrite<id3_byte_t[]>(size);
 	is.ReadFull(lock, std::as_writable_bytes(std::span{buffer.get(), size}));
 
 	return UniqueId3Tag(id3_tag_parse(buffer.get(), size));