gems: remove use of format strings

Issue #2064

repos/gems/src/app/decorator/window.h

@@ -52,12 +52,9 @@ class Decorator::Window : public Window_base
 				/*
 				 * We supply the window ID as label for the anchor view.
 				 */
-				if (id) {
-					char buf[128];
-					Genode::snprintf(buf, sizeof(buf), "%d", id);
-
-					_gui.enqueue<Command::Title>(_handle, Genode::Cstring(buf));
-				}
+				if (id)
+					_gui.enqueue<Command::Title>(_handle,
+					                             Genode::String<128>(id).string());
 			}
 
 			~Gui_view()

repos/gems/src/app/themed_decorator/window.h

@@ -160,12 +160,9 @@ class Decorator::Window : public Window_base, public Animator::Item
 				/*
 				 * We supply the window ID as label for the anchor view.
 				 */
-				if (id) {
-					char buf[128];
-					Genode::snprintf(buf, sizeof(buf), "%d", id);
-
-					_gui.enqueue<Command::Title>(_handle, Genode::Cstring(buf));
-				}
+				if (id)
+					_gui.enqueue<Command::Title>(_handle,
+					                             Genode::String<128>(id).string());
 			}
 
 			View_handle _create_remote_view(Gui::Session_client &remote_gui)

repos/gems/src/lib/vfs/trace/session_label.h

@@ -14,7 +14,6 @@
 #ifndef _SESSION_LABEL_H_
 #define _SESSION_LABEL_H_
 
-#include <base/snprintf.h>
 #include <util/arg_string.h>
 #include <util/string.h>
 

repos/gems/src/server/cpu_sampler/cpu_thread_component.cc

@@ -12,7 +12,7 @@
  */
 
 /* Genode includes */
-#include <base/snprintf.h>
+#include <util/string.h>
 
 /* local includes */
 #include "cpu_session_component.h"
@@ -32,28 +32,14 @@ Cpu_sampler::Cpu_thread_component::Cpu_thread_component(
                                 addr_t                   utcb,
                                 char              const *thread_name,
                                 unsigned int             thread_id)
-: _cpu_session_component(cpu_session_component), _env(env),
-  _md_alloc(md_alloc),
-  _parent_cpu_thread(
-      _cpu_session_component.parent_cpu_session().create_thread(pd,
-                                                                name,
-                                                                affinity,
-                                                                weight,
-                                                                utcb))
+:
+	_cpu_session_component(cpu_session_component), _env(env), _md_alloc(md_alloc),
+	_parent_cpu_thread(
+		_cpu_session_component.parent_cpu_session()
+		                      .create_thread(pd, name, affinity, weight, utcb)),
+	_label(_cpu_session_component.session_label().string(), " -> ", thread_name),
+	_log_session_label("samples -> ", _label, ".", thread_id)
 {
-	char label_buf[Session_label::size()];
-
-	snprintf(label_buf, sizeof(label_buf), "%s -> %s",
-	         _cpu_session_component.session_label().string(),
-	         thread_name);
-
-	_label = Session_label(label_buf);
-
-	snprintf(label_buf, sizeof(label_buf), "samples -> %s.%u",
-             _label.string(), thread_id);
-
-    _log_session_label = Session_label(label_buf);
-
 	_cpu_session_component.thread_ep().manage(this);
 }
 
@@ -121,21 +107,13 @@ void Cpu_sampler::Cpu_thread_component::flush()
 		_log.construct(_env, _log_session_label);
 
 	/* number of hex characters + newline + '\0' */
-	enum { SAMPLE_STRING_SIZE = 2 * sizeof(addr_t) + 1 + 1 };
-
-	char sample_string[SAMPLE_STRING_SIZE];
-
-	char const *format_string;
-
-	if (sizeof(addr_t) == 8)
-		format_string = "%16lX\n";
-	else
-		format_string = "%8X\n";
+	using Sample = String<2 * sizeof(addr_t) + 1 + 1>;
 
 	for (unsigned int i = 0; i < _sample_buf_index; i++) {
-		snprintf(sample_string, SAMPLE_STRING_SIZE, format_string,
-		         _sample_buf[i]);
-		_log->write(sample_string);
+
+		Sample const sample(Hex(_sample_buf[i], Hex::OMIT_PREFIX, Hex::PAD), "\n");
+
+		_log->write(sample.string());
 	}
 
 	_sample_buf_index = 0;

repos/gems/src/server/wm/gui.h

@@ -883,16 +883,16 @@ class Wm::Gui::Session_component : public Rpc_object<Gui::Session>,
 
 		bool matches_session_label(char const *selector) const
 		{
+			using namespace Genode;
+
 			/*
 			 * Append label separator to match selectors with a trailing
 			 * separator.
 			 *
-			 * The code originates from nitpicker's 'session.h'.
+			 * The code snippet originates from nitpicker's 'gui_session.h'.
 			 */
-			char label[Genode::Session_label::capacity() + 4];
-			Genode::snprintf(label, sizeof(label), "%s ->", _session_label.string());
-			return Genode::strcmp(label, selector,
-			                      Genode::strlen(selector)) == 0;
+			String<Session_label::capacity() + 4> const label(_session_label, " ->");
+			return strcmp(label.string(), selector, strlen(selector)) == 0;
 		}
 
 		void request_resize(Area size)

repos/os/include/decorator/window.h

@@ -19,7 +19,6 @@
 #include <util/xml_generator.h>
 #include <util/list_model.h>
 #include <gui_session/client.h>
-#include <base/snprintf.h>
 
 /* decorator includes */
 #include <decorator/types.h>