buffer: Refactor

src/buffer.h

@@ -29,21 +29,21 @@
 
 #include <cstring>
 #include <algorithm>
+#include <array>
 
 namespace nghttp2 {
 
 template <size_t N> struct Buffer {
-  Buffer() : pos(begin), last(begin) {}
+  Buffer() : pos(std::begin(buf)), last(pos) {}
   // Returns the number of bytes to read.
   size_t rleft() const { return last - pos; }
   // Returns the number of bytes this buffer can store.
-  size_t wleft() const { return begin + N - last; }
+  size_t wleft() const { return std::end(buf) - last; }
   // Writes up to min(wleft(), |count|) bytes from buffer pointed by
-  // |buf|.  Returns number of bytes written.
-  size_t write(const void *buf, size_t count) {
+  // |src|.  Returns number of bytes written.
+  size_t write(const void *src, size_t count) {
     count = std::min(count, wleft());
-    memcpy(last, buf, count);
-    last += count;
+    last = std::copy_n(static_cast<const uint8_t *>(src), count, last);
     return count;
   }
   size_t write(size_t count) {
@@ -57,8 +57,8 @@ template <size_t N> struct Buffer {
     pos += count;
     return count;
   }
-  void reset() { pos = last = begin; }
-  uint8_t begin[N];
+  void reset() { pos = last = std::begin(buf); }
+  std::array<uint8_t, N> buf;
   uint8_t *pos, *last;
 };
 

src/buffer_test.cc

@@ -45,13 +45,13 @@ void test_buffer_write(void) {
 
   CU_ASSERT(3 == b.rleft());
   CU_ASSERT(13 == b.wleft());
-  CU_ASSERT(0 == b.pos - b.begin);
+  CU_ASSERT(0 == b.pos - std::begin(b.buf));
 
   b.drain(3);
 
   CU_ASSERT(0 == b.rleft());
   CU_ASSERT(13 == b.wleft());
-  CU_ASSERT(3 == b.pos - b.begin);
+  CU_ASSERT(3 == b.pos - std::begin(b.buf));
 
   auto n = b.write("0123456789ABCDEF", 16);
 
@@ -59,20 +59,20 @@ void test_buffer_write(void) {
 
   CU_ASSERT(13 == b.rleft());
   CU_ASSERT(0 == b.wleft());
-  CU_ASSERT(3 == b.pos - b.begin);
+  CU_ASSERT(3 == b.pos - std::begin(b.buf));
   CU_ASSERT(0 == memcmp(b.pos, "0123456789ABC", 13));
 
   b.reset();
 
   CU_ASSERT(0 == b.rleft());
   CU_ASSERT(0 == b.wleft());
-  CU_ASSERT(0 == b.pos - b.begin);
+  CU_ASSERT(0 == b.pos - std::begin(b.buf));
 
   b.write(5);
 
   CU_ASSERT(5 == b.rleft());
   CU_ASSERT(11 == b.wleft());
-  CU_ASSERT(0 == b.pos - b.begin);
+  CU_ASSERT(0 == b.pos - std::begin(b.buf));
 }
 
 } // namespace nghttp2