Express reserve() using prepare() and comment both

Author: nordlow

source/mir/appender.d

@@ -38,49 +38,14 @@ struct ScopedBuffer(T, size_t bytes = 4096)
  return *cast(inout(T[_bufferLength])*)&_scopeBufferPayload;
  }
 
- ///
- void reserve(size_t n) @trusted scope
+ /// Reserve `n` extra more elements.
+ void reserve(size_t n) @safe scope
  {
- import mir.internal.memory: realloc, malloc;
- const nextLength = _currentLength + n;
- if (_buffer.length == 0)
- {
- if (nextLength <= _bufferLength)
- {
- return;
- }
- else
- {
- const newLen = nextLength << 1;
- if (auto p = malloc(T.sizeof * newLen))
- {
- _buffer = (cast(T*)p)[0 .. newLen];
- }
- else assert(0);
- version (mir_secure_memory)
- {
- (cast(ubyte[])_buffer)[] = 0;
- }
- memcpy(cast(void*)_buffer.ptr, _scopeBuffer.ptr, T.sizeof * (nextLength - n));
- }
- }
- else
- if (nextLength > _buffer.length)
- {
- const newLen = nextLength << 1;
- if (auto p = realloc(cast(void*)_buffer.ptr, T.sizeof * newLen))
- {
- _buffer = (cast(T*)p)[0 .. newLen];
- }
- else assert(0);
- version (mir_secure_memory)
- {
- (cast(ubyte[])_buffer[nextLength .. $])[] = 0;
- }
- }
+ prepare(n);
+ _currentLength -= n;
  }
 
- ///
+ /// Return a slice to `n` more elements.
  T[] prepare(size_t n) @trusted scope
  {
  import mir.internal.memory: realloc, malloc;