Merge pull request #3966 from randombit/jack/constexpr-buffer-stuffer

Apply constexpr to BufferStuffer

src/lib/utils/stl_util.h

@@ -198,13 +198,13 @@ class BufferSlicer final {
  */
 class BufferStuffer {
    public:
-      BufferStuffer(std::span<uint8_t> buffer) : m_buffer(buffer) {}
+      constexpr BufferStuffer(std::span<uint8_t> buffer) : m_buffer(buffer) {}
 
       /**
        * @returns a span for the next @p bytes bytes in the concatenated buffer.
        *          Checks that the buffer is not exceded.
        */
-      std::span<uint8_t> next(size_t bytes) {
+      constexpr std::span<uint8_t> next(size_t bytes) {
          BOTAN_STATE_CHECK(m_buffer.size() >= bytes);
 
          auto result = m_buffer.first(bytes);
@@ -213,7 +213,7 @@ class BufferStuffer {
       }
 
       template <size_t bytes>
-      std::span<uint8_t, bytes> next() {
+      constexpr std::span<uint8_t, bytes> next() {
          BOTAN_STATE_CHECK(m_buffer.size() >= bytes);
 
          auto result = m_buffer.first<bytes>();
@@ -229,21 +229,21 @@ class BufferStuffer {
       /**
        * @returns a reference to the next single byte in the buffer
        */
-      uint8_t& next_byte() { return next(1)[0]; }
+      constexpr uint8_t& next_byte() { return next(1)[0]; }
 
-      void append(std::span<const uint8_t> buffer) {
+      constexpr void append(std::span<const uint8_t> buffer) {
          auto sink = next(buffer.size());
          std::copy(buffer.begin(), buffer.end(), sink.begin());
       }
 
-      void append(uint8_t b, size_t repeat = 1) {
+      constexpr void append(uint8_t b, size_t repeat = 1) {
          auto sink = next(repeat);
          std::fill(sink.begin(), sink.end(), b);
       }
 
-      bool full() const { return m_buffer.empty(); }
+      constexpr bool full() const { return m_buffer.empty(); }
 
-      size_t remaining_capacity() const { return m_buffer.size(); }
+      constexpr size_t remaining_capacity() const { return m_buffer.size(); }
 
    private:
       std::span<uint8_t> m_buffer;