Kernel: Avoid some allocations in command line parsing (SerenityOS#3213)

1. Preallocate args hashmap to prevent rehashing. 2. Use move to prevent string copies.
lanmonster · Aug 23, 2020 · 7506adb · 7506adb
1 parent 1b075ff
commit 7506adb
Showing 1 changed file with 5 additions and 3 deletions.
diff --git a/Kernel/CommandLine.cpp b/Kernel/CommandLine.cpp
@@ -46,17 +46,19 @@ CommandLine::CommandLine(const String& string)
 {
  s_the = this;
 
- for (auto str : m_string.split(' ')) {
+ const auto& args = m_string.split(' ');
+ m_params.ensure_capacity(args.size());
+ for (auto&& str : args) {
  if (str == "") {
  continue;
  }
 
  auto pair = str.split_limit('=', 2);
 
  if (pair.size() == 1) {
- m_params.set(pair[0], "");
+ m_params.set(move(pair[0]), "");
  } else {
- m_params.set(pair[0], pair[1]);
+ m_params.set(move(pair[0]), move(pair[1]));
  }
  }
 }