Method append

3rdparty/imgui/src/imgui.cpp:3154–3170

char ImGuiTextBuffer::EmptyString[1] = { 0 };

void ImGuiTextBuffer::append(const char* str, const char* str_end)
{
    int len = str_end ? (int)(str_end - str) : (int)ImStrlen(str);

    // Add zero-terminator the first time
    const int write_off = (Buf.Size != 0) ? Buf.Size : 1;
    const int needed_sz = write_off + len;
    if (write_off + len >= Buf.Capacity)
    {
        int new_capacity = Buf.Capacity * 2;
        Buf.reserve(needed_sz > new_capacity ? needed_sz : new_capacity);
    }

    Buf.resize(needed_sz);
    memcpy(&Buf[write_off - 1], str, (size_t)len);
    Buf[write_off - 1 + len] = 0;
}

void ImGuiTextBuffer::appendf(const char* fmt, ...)
{