Merge pull request #2492 from janisozaur/countof

countof with type safety

projects/openrct2.vcxproj

@@ -208,6 +208,7 @@
     <ClInclude Include="..\src\core\Memory.hpp" />
     <ClInclude Include="..\src\core\StringBuilder.hpp" />
     <ClInclude Include="..\src\core\StringReader.hpp" />
+    <ClInclude Include="..\src\core\Util.hpp" />
     <ClInclude Include="..\src\cursors.h" />
     <ClInclude Include="..\src\diagnostic.h" />
     <ClInclude Include="..\src\drawing\drawing.h" />

src/audio/mixer.cpp

@@ -27,6 +27,7 @@ extern "C" {
 }
 #include "mixer.h"
 #include <cmath>
+#include "../core/Util.hpp"
 
 Mixer gMixer;
 
@@ -434,10 +435,10 @@ Mixer::Mixer()
 {
 	effectbuffer = 0;
 	volume = 1;
-	for (int i = 0; i < countof(css1sources); i++) {
+	for (size_t i = 0; i < Util::CountOf(css1sources); i++) {
 		css1sources[i] = 0;
 	}
-	for (int i = 0; i < countof(musicsources); i++) {
+	for (size_t i = 0; i < Util::CountOf(musicsources); i++) {
 		musicsources[i] = 0;
 	}
 }
@@ -458,7 +459,7 @@ void Mixer::Init(const char* device)
 	format.channels = have.channels;
 	format.freq = have.freq;
 	const char* filename = get_file_path(PATH_ID_CSS1);
-	for (int i = 0; i < countof(css1sources); i++) {
+	for (size_t i = 0; i < Util::CountOf(css1sources); i++) {
 		Source_Sample* source_sample = new Source_Sample;
 		if (source_sample->LoadCSS1(filename, i)) {
 			source_sample->Convert(format); // convert to audio output format, saves some cpu usage but requires a bit more memory, optional
@@ -481,13 +482,13 @@ void Mixer::Close()
 	}
 	Unlock();
 	SDL_CloseAudioDevice(deviceid);
-	for (int i = 0; i < countof(css1sources); i++) {
+	for (size_t i = 0; i < Util::CountOf(css1sources); i++) {
 		if (css1sources[i] && css1sources[i] != &source_null) {
 			delete css1sources[i];
 			css1sources[i] = 0;
 		}
 	}
-	for (int i = 0; i < countof(musicsources); i++) {
+	for (size_t i = 0; i < Util::CountOf(musicsources); i++) {
 		if (musicsources[i] && musicsources[i] != &source_null) {
 			delete musicsources[i];
 			musicsources[i] = 0;
@@ -530,9 +531,9 @@ void Mixer::Stop(Channel& channel)
 	Unlock();
 }
 
-bool Mixer::LoadMusic(int pathId)
+bool Mixer::LoadMusic(size_t pathId)
 {
-	if (pathId >= countof(musicsources)) {
+	if (pathId >= Util::CountOf(musicsources)) {
 		return false;
 	}
 	if (!musicsources[pathId]) {
@@ -797,14 +798,14 @@ void Mixer_Init(const char* device)
 	gMixer.Init(device);
 }
 
-void* Mixer_Play_Effect(int id, int loop, int volume, float pan, double rate, int deleteondone)
+void* Mixer_Play_Effect(size_t id, int loop, int volume, float pan, double rate, int deleteondone)
 {
 	if (gOpenRCT2Headless) return 0;
 
 	if (!gConfigSound.sound) {
 		return 0;
 	}
-	if (id >= countof(gMixer.css1sources)) {
+	if (id >= Util::CountOf(gMixer.css1sources)) {
 		return 0;
 	}
 	gMixer.Lock();

src/audio/mixer.h

@@ -166,7 +166,7 @@ public:
 	void Unlock();
 	Channel* Play(Source& source, int loop, bool deleteondone, bool deletesourceondone);
 	void Stop(Channel& channel);
-	bool LoadMusic(int pathid);
+	bool LoadMusic(size_t pathid);
 	void SetVolume(float volume);
 
 	Source* css1sources[SOUND_MAXID];
@@ -201,7 +201,7 @@ extern "C"
 #endif
 
 void Mixer_Init(const char* device);
-void* Mixer_Play_Effect(int id, int loop, int volume, float pan, double rate, int deleteondone);
+void* Mixer_Play_Effect(size_t id, int loop, int volume, float pan, double rate, int deleteondone);
 void Mixer_Stop_Channel(void* channel);
 void Mixer_Channel_Volume(void* channel, int volume);
 void Mixer_Channel_Pan(void* channel, float pan);

src/core/Util.hpp

@@ -0,0 +1,20 @@
+#ifndef _UTIL_HPP_
+#define _UTIL_HPP_
+
+#include <cstdlib>
+
+/**
+ * Common utility functions.
+ */
+namespace Util {
+
+// Based on http://www.g-truc.net/post-0708.html
+template <typename T, size_t N>
+constexpr size_t CountOf(T const (&)[N]) noexcept
+{
+	return N;
+}
+
+} // namespace Util
+
+#endif // _UTIL_HPP_

src/network/network.cpp

@@ -36,6 +36,7 @@ extern "C" {
 #include <algorithm>
 #include <set>
 #include <string>
+#include "../core/Util.hpp"
 extern "C" {
 #include "../config.h"
 #include "../game.h"
@@ -844,10 +845,10 @@ std::string Network::GenerateAdvertiseKey()
 	static char hexChars[] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };
 	char key[17];
 	for (int i = 0; i < 16; i++) {
-		int hexCharIndex = util_rand() % countof(hexChars);
+		int hexCharIndex = util_rand() % Util::CountOf(hexChars);
 		key[i] = hexChars[hexCharIndex];
 	}
-	key[countof(key) - 1] = 0;
+	key[Util::CountOf(key) - 1] = 0;
 
 	return key;
 }

src/platform/posix.c

@@ -554,10 +554,10 @@ void platform_resolve_user_data_path()
 	char buffer[MAX_PATH];
 	buffer[0] = '\0';
 	log_verbose("buffer = '%s'", buffer);
-	
+
 	const char *homedir = getpwuid(getuid())->pw_dir;
 	platform_posix_sub_user_data_path(buffer, homedir, separator);
-	
+
 	log_verbose("OpenRCT2 user data directory = '%s'", buffer);
 	int len = strnlen(buffer, MAX_PATH);
 	wchar_t *w_buffer = regular_to_wchar(buffer);

src/rct2.h

@@ -81,7 +81,30 @@ typedef utf16* utf16string;
 // Rounds an integer down to the given power of 2. y must be a power of 2.
 #define floor2(x, y)		((x) & (~((y) - 1)))
 
-#define countof(x)			((sizeof(x)/sizeof(0[x])) / ((size_t)(!(sizeof(x) % sizeof(0[x])))))
+
+#ifndef __cplusplus
+// in C++ you should be using Util::CountOf
+#ifdef __GNUC__
+/**
+ * Force a compilation error if condition is true, but also produce a
+ * result (of value 0 and type size_t), so the expression can be used
+ * e.g. in a structure initializer (or where-ever else comma expressions
+ * aren't permitted).
+ */
+#define BUILD_BUG_ON_ZERO(e) (sizeof(struct { int:-!!(e); }))
+
+/* &a[0] degrades to a pointer: a different type from an array */
+#define __must_be_array(a) \
+        BUILD_BUG_ON_ZERO(__builtin_types_compatible_p(typeof(a), typeof(&a[0])))
+
+// based on http://lxr.free-electrons.com/source/include/linux/kernel.h#L54
+#define countof(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
+#elif defined (_MSC_VER)
+	#define countof(arr)			_countof(arr)
+#else
+	#define countof(arr)			(sizeof(arr) / sizeof((arr)[0]))
+#endif // __GNUC__
+#endif // __cplusplus
 
 #ifndef _MSC_VER
 // use similar struct packing as MSVC for our structs