Fix various compiler warnings in MSVC (non graphics edition)

- Put in casts/checks in audio code when assigning size_t to 32 bit
- () is different from (void)
- Turned off warnings for anonymous unions and negating unsigned integers which were technically accurate but unhelpful (and interfered with bit conversion and a weird bit math construct in audio.c) (CMakeLists only)

CMakeLists.txt

@@ -597,7 +597,7 @@ if(WIN32)
   target_sources(lovr PRIVATE src/core/os_win32.c)
   target_sources(lovr PRIVATE etc/lovr.rc)
   if (MSVC)
-    set_target_properties(lovr PROPERTIES COMPILE_FLAGS "/wd4244 /MP")
+    set_target_properties(lovr PROPERTIES COMPILE_FLAGS "/wd4244 /wd4146 /wd4116 /MP")
   else()
     set_target_properties(lovr PROPERTIES COMPILE_FLAGS "-MP")
   endif()

src/api/l_data_sound.c

@@ -51,8 +51,9 @@ static int l_lovrSoundGetSampleRate(lua_State* L) {
 
 static int l_lovrSoundGetByteStride(lua_State* L) {
   Sound* sound = luax_checktype(L, 1, Sound);
-  uint32_t stride = lovrSoundGetStride(sound);
-  lua_pushinteger(L, stride);
+  size_t stride = lovrSoundGetStride(sound);
+  lovrCheck(stride < UINT32_MAX, "Sound contains impossibly many channels");
+  lua_pushinteger(L, (uint32_t)stride);
   return 1;
 }
 
@@ -125,7 +126,7 @@ static int l_lovrSoundGetFrames(lua_State* L) {
       uint32_t frames = 0;
       while (frames < count) {
         char buffer[4096];
-        uint32_t chunk = MIN(sizeof(buffer) / stride, count - frames);
+        uint32_t chunk = MIN((uint32_t)(sizeof(buffer) / stride), count - frames);
         uint32_t read = lovrSoundRead(sound, srcOffset + frames, chunk, buffer);
         uint32_t samples = read * channels;
         if (read == 0) break;
@@ -189,7 +190,9 @@ static int l_lovrSoundSetFrames(lua_State* L) {
     if (blob) {
       uint32_t srcOffset = luax_optu32(L, 5, 0);
       uint32_t dstOffset = luax_optu32(L, 4, 0);
-      uint32_t count = luax_optu32(L, 3, (blob->size - srcOffset) / stride);
+      size_t defaultCount = (blob->size - srcOffset) / stride;
+      lovrCheck(defaultCount <= UINT32_MAX, "Sound is too big to work with (somewhere over 4 GiB)");
+      uint32_t count = luax_optu32(L, 3, (uint32_t)defaultCount);
       uint32_t frames = lovrSoundWrite(sound, dstOffset, count, (char*) blob->data + srcOffset);
       lua_pushinteger(L, frames);
       return 1;
@@ -221,7 +224,7 @@ static int l_lovrSoundSetFrames(lua_State* L) {
   uint32_t frames = 0;
   while (frames < count) {
     char buffer[4096];
-    uint32_t chunk = MIN(sizeof(buffer) / stride, count - frames);
+    uint32_t chunk = MIN((uint32_t)(sizeof(buffer) / stride), count - frames);
     uint32_t samples = chunk * channels;
 
     if (format == SAMPLE_I16) {

src/modules/audio/audio.c

@@ -14,6 +14,7 @@
 #define CTZL __builtin_ctzl
 #endif
 
+// Mysterious "m ^= (m & -m)" construct zeroes the lowest nonzero bit.
 #define FOREACH_SOURCE(s) for (uint64_t m = state.sourceMask; s = m ? state.sources[CTZL(m)] : NULL, m; m ^= (m & -m))
 #define OUTPUT_FORMAT SAMPLE_F32
 #define OUTPUT_CHANNELS 2

src/modules/data/sound.c

@@ -68,8 +68,10 @@ static uint32_t lovrSoundReadMp3(Sound* sound, uint32_t offset, uint32_t count,
   }
 
   uint32_t channels = lovrSoundGetChannelCount(sound);
-  size_t samples = mp3dec_ex_read(sound->decoder, data, count * channels);
-  uint32_t frames = samples / channels;
+  uint32_t readSamples = (uint32_t)(count * channels);
+  lovrCheck(readSamples/count == channels, "Cannot request more than 2^32-1 samples of sound data at a time"); // Check for overflow
+  size_t samples = mp3dec_ex_read(sound->decoder, data, readSamples);
+  uint32_t frames = ((uint32_t)samples / channels);
   sound->cursor += frames;
   return frames;
 }
@@ -135,7 +137,9 @@ static bool loadOgg(Sound* sound, Blob* blob, bool decode) {
     void* data = calloc(1, size);
     lovrAssert(data, "Out of memory");
     sound->blob = lovrBlobCreate(data, size, "Sound");
-    if (stb_vorbis_get_samples_float_interleaved(sound->decoder, lovrSoundGetChannelCount(sound), data, size / sizeof(float)) < (int) sound->frames) {
+    size_t samples = size / sizeof(float);
+    lovrCheck(samples < INT_MAX, "Sound is too big to work with (somewhere over 2 GiB)");
+    if (stb_vorbis_get_samples_float_interleaved(sound->decoder, lovrSoundGetChannelCount(sound), data, (int)(samples)) < (int) sound->frames) {
       lovrThrow("Could not decode vorbis from '%s'", blob->name);
     }
     stb_vorbis_close(sound->decoder);
@@ -285,7 +289,9 @@ static bool loadMP3(Sound* sound, Blob* blob, bool decode) {
     sound->format = SAMPLE_F32;
     sound->sampleRate = info.hz;
     sound->layout = info.channels == 2 ? CHANNEL_STEREO : CHANNEL_MONO;
-    sound->frames = info.samples / info.channels;
+    size_t frames = info.samples / info.channels;
+    lovrCheck(frames < UINT32_MAX, "Sound is too long (2^32 or more samples)")
+    sound->frames = (uint32_t)frames;
     sound->read = lovrSoundReadRaw;
     return true;
   } else {

src/modules/system/system.c

@@ -36,7 +36,7 @@ static void onPermission(os_permission permission, bool granted) {
   });
 }
 
-static void onQuit() {
+static void onQuit(void) {
   lovrEventPush((Event) {
     .type = EVENT_QUIT,
     .data.quit.exitCode = 0