C++ file::trunc方法代码示例

void save_gui_cfg()
{
	YAML::Emitter out;
	out.SetSeqFormat(YAML::Flow);
	out << g_gui_cfg;

	// Save to file
	s_gui_cfg.seek(0);
	s_gui_cfg.trunc(0);
	s_gui_cfg.write(out.c_str(), out.size());
}

//.........这里部分代码省略.........
	s_subpanel_core1->Add(chbox_core_load_liblv2, wxSizerFlags().Border(wxALL, 5).Expand());
	s_subpanel_core2->Add(s_round_core_lle, wxSizerFlags().Border(wxALL, 5).Expand());
	s_subpanel_core->Add(s_subpanel_core1);
	s_subpanel_core->Add(s_subpanel_core2);

	// Graphics
	s_subpanel_graphics1->Add(s_round_gs_render, wxSizerFlags().Border(wxALL, 5).Expand());
	s_subpanel_graphics1->Add(s_round_gs_res, wxSizerFlags().Border(wxALL, 5).Expand());
	s_subpanel_graphics1->Add(s_round_gs_d3d_adapter, wxSizerFlags().Border(wxALL, 5).Expand());
	s_subpanel_graphics1->Add(chbox_gs_dump_color, wxSizerFlags().Border(wxALL, 5).Expand());
	s_subpanel_graphics1->Add(chbox_gs_read_color, wxSizerFlags().Border(wxALL, 5).Expand());
	s_subpanel_graphics1->Add(chbox_gs_dump_depth, wxSizerFlags().Border(wxALL, 5).Expand());
	s_subpanel_graphics1->Add(chbox_gs_read_depth, wxSizerFlags().Border(wxALL, 5).Expand());
	s_subpanel_graphics1->Add(chbox_gs_gl_legacy_buffers, wxSizerFlags().Border(wxALL, 5).Expand());
	s_subpanel_graphics2->Add(s_round_gs_aspect, wxSizerFlags().Border(wxALL, 5).Expand());
	s_subpanel_graphics2->Add(s_round_gs_frame_limit, wxSizerFlags().Border(wxALL, 5).Expand());
	s_subpanel_graphics2->AddSpacer(68);
	s_subpanel_graphics2->Add(chbox_gs_debug_output, wxSizerFlags().Border(wxALL, 5).Expand());
	s_subpanel_graphics2->Add(chbox_gs_overlay, wxSizerFlags().Border(wxALL, 5).Expand());
	s_subpanel_graphics2->Add(chbox_gs_log_prog, wxSizerFlags().Border(wxALL, 5).Expand());
	s_subpanel_graphics2->Add(chbox_gs_vsync, wxSizerFlags().Border(wxALL, 5).Expand());
	s_subpanel_graphics->Add(s_subpanel_graphics1);
	s_subpanel_graphics->Add(s_subpanel_graphics2);

	// Input - Output
	s_subpanel_io1->Add(s_round_io_pad_handler, wxSizerFlags().Border(wxALL, 5).Expand());
	s_subpanel_io1->Add(s_round_io_keyboard_handler, wxSizerFlags().Border(wxALL, 5).Expand());
	s_subpanel_io1->Add(s_round_io_mouse_handler, wxSizerFlags().Border(wxALL, 5).Expand());
	s_subpanel_io2->Add(s_round_io_camera, wxSizerFlags().Border(wxALL, 5).Expand());
	s_subpanel_io2->Add(s_round_io_camera_type, wxSizerFlags().Border(wxALL, 5).Expand());
	s_subpanel_io->Add(s_subpanel_io1);
	s_subpanel_io->Add(s_subpanel_io2);

	// Audio
	s_subpanel_audio->Add(s_round_audio_out, wxSizerFlags().Border(wxALL, 5).Expand());
	s_subpanel_audio->Add(chbox_audio_dump, wxSizerFlags().Border(wxALL, 5).Expand());
	s_subpanel_audio->Add(chbox_audio_conv, wxSizerFlags().Border(wxALL, 5).Expand());

	// Miscellaneous
	s_subpanel_misc->Add(chbox_hle_exitonstop, wxSizerFlags().Border(wxALL, 5).Expand());
	s_subpanel_misc->Add(chbox_hle_always_start, wxSizerFlags().Border(wxALL, 5).Expand());

	// Auto Pause
	s_subpanel_misc->Add(chbox_dbg_ap_systemcall, wxSizerFlags().Border(wxALL, 5).Expand());
	s_subpanel_misc->Add(chbox_dbg_ap_functioncall, wxSizerFlags().Border(wxALL, 5).Expand());

	// Networking
	s_subpanel_networking->Add(s_round_net_status, wxSizerFlags().Border(wxALL, 5).Expand());

	// System
	s_subpanel_system->Add(chbox_vfs_enable_host_root, wxSizerFlags().Border(wxALL, 5).Expand());
	s_subpanel_system->Add(s_round_sys_lang, wxSizerFlags().Border(wxALL, 5).Expand());

	// Buttons
	wxBoxSizer* s_b_panel(new wxBoxSizer(wxHORIZONTAL));
	s_b_panel->Add(new wxButton(this, wxID_OK), wxSizerFlags().Border(wxALL, 5).Bottom());
	s_b_panel->Add(new wxButton(this, wxID_CANCEL), wxSizerFlags().Border(wxALL, 5).Bottom());

	// Resize panels
	SetSizerAndFit(s_subpanel_core, false);
	SetSizerAndFit(s_subpanel_graphics, false);
	SetSizerAndFit(s_subpanel_io, false);
	SetSizerAndFit(s_subpanel_audio, false);
	SetSizerAndFit(s_subpanel_misc, false);
	SetSizerAndFit(s_subpanel_networking, false);
	SetSizerAndFit(s_subpanel_system, false);
	SetSizerAndFit(s_b_panel, false);

	SetSize(width + 26, height + 80);

	if (ShowModal() == wxID_OK)
	{
		std::set<std::string> lle_selected;

		for (auto& i : lle_module_list)
		{
			if (i.second) // selected
			{
				lle_selected.emplace(i.first);
			}
		}

		saved.reset();
		saved["Core"]["Load libraries"] = std::vector<std::string>(lle_selected.begin(), lle_selected.end());

		for (auto& pad : pads)
		{
			pad->save();
		}

		loaded += saved;
		YAML::Emitter out;
		emit(out, loaded);

		// Save config
		config.seek(0);
		config.trunc(0);
		config.write(out.c_str(), out.size());
	}
}

	void save_object(const fs::file& stream, const psf::registry& psf)
	{
		std::vector<def_table_t> indices; indices.reserve(psf.size());

		// Generate indices and calculate key table length
		std::size_t key_offset = 0, data_offset = 0;

		for (const auto& entry : psf)
		{
			def_table_t index;
			index.key_off = ::narrow<u32>(key_offset);
			index.param_fmt = entry.second.type();
			index.param_len = entry.second.size();
			index.param_max = entry.second.max();
			index.data_off = ::narrow<u32>(data_offset);

			// Update offsets:
			key_offset += ::narrow<u32>(entry.first.size() + 1); // key size
			data_offset += index.param_max;

			indices.push_back(index);
		}

		// Align next section (data) offset
		key_offset = ::align(key_offset, 4);

		// Generate header
		header_t header;
		header.magic = "\0PSF"_u32;
		header.version = 0x101;
		header.off_key_table = ::narrow<u32>(sizeof(header_t) + sizeof(def_table_t) * psf.size());
		header.off_data_table = ::narrow<u32>(header.off_key_table + key_offset);
		header.entries_num = ::narrow<u32>(psf.size());

		// Save header and indices
		stream.write(header);
		stream.write(indices);

		// Save key table
		for (const auto& entry : psf)
		{
			stream.write(entry.first);
			stream.write('\0');
		}

		// Skip padding
		stream.trunc(stream.seek(header.off_data_table));

		// Save data
		for (const auto& entry : psf)
		{
			const auto fmt = entry.second.type();
			const u32 max = entry.second.max();

			if (fmt == format::integer && max == sizeof(u32))
			{
				const le_t<u32> value = entry.second.as_integer();
				stream.write(value);
			}
			else if (fmt == format::string || fmt == format::array)
			{
				const std::string& value = entry.second.as_string();
				const std::size_t size = std::min<std::size_t>(max, value.size());

				if (value.size() + (fmt == format::string) > max)
				{
					// TODO: check real limitations of PSF format
					LOG_ERROR(LOADER, "Entry value shrinkage (key='%s', value='%s', size=0x%zx, max=0x%x)", entry.first, value, size, max);
				}

				stream.write(value);
				stream.trunc(stream.seek(max - size, fs::seek_cur)); // Skip up to max_size
			}
			else
			{
				fmt::throw_exception("Invalid entry format (key='%s', fmt=0x%x)" HERE, entry.first, fmt);
			}
		}
	}