Function append

Tools/EditorFramework/pugixml.cpp:6583–6620

	}

	void append(const xpath_string& o, xpath_allocator* alloc)
	{
		// skip empty sources
		if (!*o._buffer)
			return;

		// fast append for constant empty target and constant source
		if (!*_buffer && !_uses_heap && !o._uses_heap)
		{
			_buffer = o._buffer;
		}
		else
		{
			// need to make heap copy
			size_t target_length = strlength(_buffer);
			size_t source_length = strlength(o._buffer);
			size_t result_length = target_length + source_length;

			// allocate new buffer
			char_t* result = static_cast<char_t*>(alloc->reallocate(
				_uses_heap ? const_cast<char_t*>(_buffer) : 0,
				(target_length + 1) * sizeof(char_t),
				(result_length + 1) * sizeof(char_t)));
			assert(result);

			// append first string to the new buffer in case there was no reallocation
			if (!_uses_heap)
				memcpy(result, _buffer, target_length * sizeof(char_t));

			// append second string to the new buffer
			memcpy(result + target_length, o._buffer, source_length * sizeof(char_t));
			result[result_length] = 0;

			// finalize
			_buffer = result;
			_uses_heap = true;
		}
	}

	const char_t* c_str() const
	{