perf: buffer iterators (#4220)

libtransmission/peer-io.cc

@@ -788,16 +788,13 @@ size_t tr_peerIo::getWriteBufferSpace(uint64_t now) const noexcept
 
 void tr_peerIo::write(libtransmission::Buffer& buf, bool is_piece_data)
 {
-    auto const n_bytes = std::size(buf);
-
-    auto const old_size = std::size(outbuf);
-    outbuf.add(buf);
-    for (auto iter = std::begin(outbuf) + old_size, end = std::end(outbuf); iter != end; ++iter)
+    for (auto& ch : buf)
     {
-        encrypt(1, &*iter);
+        encrypt(1, &ch);
     }
 
-    outbuf_info.emplace_back(n_bytes, is_piece_data);
+    outbuf_info.emplace_back(std::size(buf), is_piece_data);
+    outbuf.add(buf);
 }
 
 void tr_peerIo::writeBytes(void const* bytes, size_t n_bytes, bool is_piece_data)

libtransmission/peer-mse.h

@@ -81,7 +81,7 @@ class Filter
 public:
     void decryptInit(bool is_incoming, DH const&, tr_sha1_digest_t const& info_hash);
 
-    void decrypt(size_t buf_len, void* buf)
+    constexpr void decrypt(size_t buf_len, void* buf)
     {
         if (dec_active_)
         {
@@ -91,7 +91,7 @@ public:
 
     void encryptInit(bool is_incoming, DH const&, tr_sha1_digest_t const& info_hash);
 
-    void encrypt(size_t buf_len, void* buf)
+    constexpr void encrypt(size_t buf_len, void* buf)
     {
         if (enc_active_)
         {

libtransmission/tr-buffer.h

@@ -42,14 +42,14 @@ public:
             setOffset(offset);
         }
 
-        [[nodiscard]] value_type& operator*() noexcept
+        [[nodiscard]] constexpr value_type& operator*() noexcept
         {
-            return reinterpret_cast<value_type*>(iov_.iov_base)[iov_offset_];
+            return static_cast<value_type*>(iov_.iov_base)[iov_offset_];
         }
 
-        [[nodiscard]] value_type operator*() const noexcept
+        [[nodiscard]] constexpr value_type operator*() const noexcept
         {
-            return reinterpret_cast<value_type*>(iov_.iov_base)[iov_offset_];
+            return static_cast<value_type*>(iov_.iov_base)[iov_offset_];
         }
 
         [[nodiscard]] Iterator operator+(size_t n_bytes)
@@ -172,32 +172,32 @@ public:
 
     [[nodiscard]] auto begin() noexcept
     {
-        return Iterator(buf_.get(), 0U);
+        return Iterator{ buf_.get(), 0U };
     }
 
     [[nodiscard]] auto end() noexcept
     {
-        return Iterator(buf_.get(), size());
+        return Iterator{ buf_.get(), size() };
     }
 
     [[nodiscard]] auto begin() const noexcept
     {
-        return Iterator(buf_.get(), 0U);
+        return Iterator{ buf_.get(), 0U };
     }
 
     [[nodiscard]] auto end() const noexcept
     {
-        return Iterator(buf_.get(), size());
+        return Iterator{ buf_.get(), size() };
     }
 
     [[nodiscard]] auto cbegin() const noexcept
     {
-        return Iterator(buf_.get(), 0U);
+        return Iterator{ buf_.get(), 0U };
     }
 
     [[nodiscard]] auto cend() const noexcept
     {
-        return Iterator(buf_.get(), size());
+        return Iterator{ buf_.get(), size() };
     }
 
     template<typename T>