Make and use a bit_cast function

Instead of reinterpret_casting between incompatible types

14 files changed, 40 insertions, 19 deletions

diff --git a/al/buffer.cpp b/al/buffer.cpp
index 4f0bcf8c..ad74a7f7 100644
--- a/al/buffer.cpp
+++ b/al/buffer.cpp
@@ -1463,7 +1463,7 @@ START_API_FUNC
     else switch(param)
     {
     case AL_BUFFER_CALLBACK_FUNCTION_SOFT:
-        *value = reinterpret_cast<void*>(albuf->mCallback);
+        *value = al::bit_cast<void*>(albuf->mCallback);
         break;
     case AL_BUFFER_CALLBACK_USER_PARAM_SOFT:
         *value = albuf->mUserData;
diff --git a/al/state.cpp b/al/state.cpp
index 77b104a4..fb3186c7 100644
--- a/al/state.cpp
+++ b/al/state.cpp
@@ -35,6 +35,7 @@
 #include "AL/alext.h"
 
 #include "al/debug.h"
+#include "albit.h"
 #include "alc/alu.h"
 #include "alc/context.h"
 #include "alc/inprogext.h"
@@ -516,7 +517,7 @@ START_API_FUNC
     switch(pname)
     {
     case AL_EVENT_CALLBACK_FUNCTION_SOFT:
-        *values = reinterpret_cast<void*>(context->mEventCb);
+        *values = al::bit_cast<void*>(context->mEventCb);
         break;
 
     case AL_EVENT_CALLBACK_USER_PARAM_SOFT:
@@ -524,7 +525,7 @@ START_API_FUNC
         break;
 
     case AL_DEBUG_CALLBACK_FUNCTION_EXT:
-        *values = reinterpret_cast<void*>(context->mDebugCb);
+        *values = al::bit_cast<void*>(context->mDebugCb);
         break;
 
     case AL_DEBUG_CALLBACK_USER_PARAM_EXT:
diff --git a/alc/alc.cpp b/alc/alc.cpp
index 2da5c5db..149223f4 100644
--- a/alc/alc.cpp
+++ b/alc/alc.cpp
@@ -180,7 +180,7 @@ BOOL APIENTRY DllMain(HINSTANCE module, DWORD reason, LPVOID /*reserved*/)
     case DLL_PROCESS_ATTACH:
         /* Pin the DLL so we won't get unloaded until the process terminates */
         GetModuleHandleExW(GET_MODULE_HANDLE_EX_FLAG_PIN | GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS,
-            reinterpret_cast<WCHAR*>(module), &module);
+            al::bit_cast<WCHAR*>(module), &module);
         break;
     }
     return TRUE;
diff --git a/alc/alconfig.cpp b/alc/alconfig.cpp
index 56cad9e0..ceb7d97b 100644
--- a/alc/alconfig.cpp
+++ b/alc/alconfig.cpp
@@ -38,6 +38,7 @@
 #include <string>
 #include <utility>
 
+#include "albit.h"
 #include "alfstream.h"
 #include "alstring.h"
 #include "core/helpers.h"
@@ -418,7 +419,7 @@ void ReadALConfig()
         if((configURL=CFBundleCopyResourceURL(mainBundle, CFSTR(".alsoftrc"), CFSTR(""), nullptr)) &&
            CFURLGetFileSystemRepresentation(configURL, true, fileName, sizeof(fileName)))
         {
-            f = al::ifstream{reinterpret_cast<char*>(fileName)};
+            f = al::ifstream{al::bit_cast<char*>(fileName)};
             if(f.is_open())
                 LoadConfigFromFile(f);
         }
diff --git a/alc/backends/alsa.cpp b/alc/backends/alsa.cpp
index 01021868..b162f84e 100644
--- a/alc/backends/alsa.cpp
+++ b/alc/backends/alsa.cpp
@@ -35,6 +35,7 @@
 #include <thread>
 #include <utility>
 
+#include "albit.h"
 #include "albyte.h"
 #include "alc/alconfig.h"
 #include "almalloc.h"
@@ -1204,7 +1205,7 @@ bool AlsaBackendFactory::init()
 
         error = false;
 #define LOAD_FUNC(f) do {                                                     \
-    p##f = reinterpret_cast<decltype(p##f)>(GetSymbol(alsa_handle, #f));      \
+    p##f = al::bit_cast<decltype(p##f)>(GetSymbol(alsa_handle, #f));          \
     if(p##f == nullptr) {                                                     \
         error = true;                                                         \
         missing_funcs += "\n" #f;                                             \
diff --git a/alc/backends/dsound.cpp b/alc/backends/dsound.cpp
index 51dc36f6..8b967c95 100644
--- a/alc/backends/dsound.cpp
+++ b/alc/backends/dsound.cpp
@@ -44,6 +44,7 @@
 #include <algorithm>
 #include <functional>
 
+#include "albit.h"
 #include "alnumeric.h"
 #include "comptr.h"
 #include "core/device.h"
@@ -778,7 +779,7 @@ bool DSoundBackendFactory::init()
         }
 
 #define LOAD_FUNC(f) do {                                                     \
-    p##f = reinterpret_cast<decltype(p##f)>(GetSymbol(ds_handle, #f));        \
+    p##f = al::bit_cast<decltype(p##f)>(GetSymbol(ds_handle, #f));            \
     if(!p##f)                                                                 \
     {                                                                         \
         CloseLib(ds_handle);                                                  \
diff --git a/alc/backends/jack.cpp b/alc/backends/jack.cpp
index 791002ca..dbc2b038 100644
--- a/alc/backends/jack.cpp
+++ b/alc/backends/jack.cpp
@@ -31,6 +31,7 @@
 #include <thread>
 #include <functional>
 
+#include "albit.h"
 #include "alc/alconfig.h"
 #include "alnumeric.h"
 #include "core/device.h"
@@ -126,7 +127,7 @@ bool jack_load()
 
         error = false;
 #define LOAD_FUNC(f) do {                                                     \
-    p##f = reinterpret_cast<decltype(p##f)>(GetSymbol(jack_handle, #f));      \
+    p##f = al::bit_cast<decltype(p##f)>(GetSymbol(jack_handle, #f));          \
     if(p##f == nullptr) {                                                     \
         error = true;                                                         \
         missing_funcs += "\n" #f;                                             \
@@ -135,7 +136,7 @@ bool jack_load()
         JACK_FUNCS(LOAD_FUNC);
 #undef LOAD_FUNC
         /* Optional symbols. These don't exist in all versions of JACK. */
-#define LOAD_SYM(f) p##f = reinterpret_cast<decltype(p##f)>(GetSymbol(jack_handle, #f))
+#define LOAD_SYM(f) p##f = al::bit_cast<decltype(p##f)>(GetSymbol(jack_handle, #f))
         LOAD_SYM(jack_error_callback);
 #undef LOAD_SYM
 
diff --git a/alc/backends/pipewire.cpp b/alc/backends/pipewire.cpp
index d3c8e77e..5b1596aa 100644
--- a/alc/backends/pipewire.cpp
+++ b/alc/backends/pipewire.cpp
@@ -37,6 +37,7 @@
 #include <type_traits>
 #include <utility>
 
+#include "albit.h"
 #include "albyte.h"
 #include "alc/alconfig.h"
 #include "almalloc.h"
@@ -210,7 +211,7 @@ bool pwire_load()
     }
 
 #define LOAD_FUNC(f) do {                                                     \
-    p##f = reinterpret_cast<decltype(p##f)>(GetSymbol(pwire_handle, #f));     \
+    p##f = al::bit_cast<decltype(p##f)>(GetSymbol(pwire_handle, #f));         \
     if(p##f == nullptr) missing_funcs += "\n" #f;                             \
 } while(0);
     PWIRE_FUNCS(LOAD_FUNC)
@@ -328,11 +329,11 @@ To as(From) noexcept = delete;
  * - pw_metadata
  */
 template<>
-pw_proxy* as(pw_registry *reg) noexcept { return reinterpret_cast<pw_proxy*>(reg); }
+pw_proxy* as(pw_registry *reg) noexcept { return al::bit_cast<pw_proxy*>(reg); }
 template<>
-pw_proxy* as(pw_node *node) noexcept { return reinterpret_cast<pw_proxy*>(node); }
+pw_proxy* as(pw_node *node) noexcept { return al::bit_cast<pw_proxy*>(node); }
 template<>
-pw_proxy* as(pw_metadata *mdata) noexcept { return reinterpret_cast<pw_proxy*>(mdata); }
+pw_proxy* as(pw_metadata *mdata) noexcept { return al::bit_cast<pw_proxy*>(mdata); }
 
 
 struct PwContextDeleter {
diff --git a/alc/backends/portaudio.cpp b/alc/backends/portaudio.cpp
index 9c94587d..d652d4cd 100644
--- a/alc/backends/portaudio.cpp
+++ b/alc/backends/portaudio.cpp
@@ -26,6 +26,7 @@
 #include <cstdlib>
 #include <cstring>
 
+#include "albit.h"
 #include "alc/alconfig.h"
 #include "alnumeric.h"
 #include "core/device.h"
@@ -376,7 +377,7 @@ bool PortBackendFactory::init()
             return false;
 
 #define LOAD_FUNC(f) do {                                                     \
-    p##f = reinterpret_cast<decltype(p##f)>(GetSymbol(pa_handle, #f));        \
+    p##f = al::bit_cast<decltype(p##f)>(GetSymbol(pa_handle, #f));            \
     if(p##f == nullptr)                                                       \
     {                                                                         \
         CloseLib(pa_handle);                                                  \
diff --git a/alc/backends/pulseaudio.cpp b/alc/backends/pulseaudio.cpp
index 6f706c7f..6e8bfe1b 100644
--- a/alc/backends/pulseaudio.cpp
+++ b/alc/backends/pulseaudio.cpp
@@ -38,6 +38,7 @@
 #include <sys/types.h>
 #include <utility>
 
+#include "albit.h"
 #include "albyte.h"
 #include "alc/alconfig.h"
 #include "almalloc.h"
@@ -1381,7 +1382,7 @@ bool PulseBackendFactory::init()
         }
 
 #define LOAD_FUNC(x) do {                                                     \
-    p##x = reinterpret_cast<decltype(p##x)>(GetSymbol(pulse_handle, #x));     \
+    p##x = al::bit_cast<decltype(p##x)>(GetSymbol(pulse_handle, #x));         \
     if(!(p##x)) {                                                             \
         ret = false;                                                          \
         missing_funcs += "\n" #x;                                             \
diff --git a/alc/backends/wasapi.cpp b/alc/backends/wasapi.cpp
index e66656ce..ea6ecbe0 100644
--- a/alc/backends/wasapi.cpp
+++ b/alc/backends/wasapi.cpp
@@ -207,7 +207,7 @@ NameGUIDPair get_device_name_and_guid(IMMDevice *device)
     }
 
     PropVariant pvprop;
-    hr = ps->GetValue(reinterpret_cast<const PROPERTYKEY&>(DEVPKEY_Device_FriendlyName), pvprop.get());
+    hr = ps->GetValue(al::bit_cast<PROPERTYKEY>(DEVPKEY_Device_FriendlyName), pvprop.get());
     if(FAILED(hr))
     {
         WARN("GetValue Device_FriendlyName failed: 0x%08lx\n", hr);
@@ -222,7 +222,7 @@ NameGUIDPair get_device_name_and_guid(IMMDevice *device)
     }
 
     pvprop.clear();
-    hr = ps->GetValue(reinterpret_cast<const PROPERTYKEY&>(PKEY_AudioEndpoint_GUID), pvprop.get());
+    hr = ps->GetValue(al::bit_cast<PROPERTYKEY>(PKEY_AudioEndpoint_GUID), pvprop.get());
     if(FAILED(hr))
     {
         WARN("GetValue AudioEndpoint_GUID failed: 0x%08lx\n", hr);
diff --git a/common/albit.h b/common/albit.h
index ad596208..a563a4e7 100644
--- a/common/albit.h
+++ b/common/albit.h
@@ -2,6 +2,7 @@
 #define AL_BIT_H
 
 #include <cstdint>
+#include <cstring>
 #include <limits>
 #include <type_traits>
 #if !defined(__GNUC__) && (defined(_WIN32) || defined(_WIN64))
@@ -10,6 +11,16 @@
 
 namespace al {
 
+template<typename To, typename From>
+std::enable_if_t<sizeof(To) == sizeof(From) && std::is_trivially_copyable_v<From>
+    && std::is_trivially_copyable_v<To>,
+To> bit_cast(const From &src) noexcept
+{
+    union { char c; To dst; } u;
+    std::memcpy(&u.dst, &src, sizeof(To));
+    return u.dst;
+}
+
 #ifdef __BYTE_ORDER__
 enum class endian {
     little = __ORDER_LITTLE_ENDIAN__,
diff --git a/common/dynload.cpp b/common/dynload.cpp
index f1c2a7eb..86c36e00 100644
--- a/common/dynload.cpp
+++ b/common/dynload.cpp
@@ -3,6 +3,7 @@
 
 #include "dynload.h"
 
+#include "albit.h"
 #include "strutils.h"
 
 #ifdef _WIN32
@@ -17,7 +18,7 @@ void *LoadLib(const char *name)
 void CloseLib(void *handle)
 { FreeLibrary(static_cast<HMODULE>(handle)); }
 void *GetSymbol(void *handle, const char *name)
-{ return reinterpret_cast<void*>(GetProcAddress(static_cast<HMODULE>(handle), name)); }
+{ return al::bit_cast<void*>(GetProcAddress(static_cast<HMODULE>(handle), name)); }
 
 #elif defined(HAVE_DLFCN_H)
 
diff --git a/core/dbus_wrap.cpp b/core/dbus_wrap.cpp
index 7f221706..eaddce9f 100644
--- a/core/dbus_wrap.cpp
+++ b/core/dbus_wrap.cpp
@@ -8,6 +8,7 @@
 #include <mutex>
 #include <type_traits>
 
+#include "albit.h"
 #include "logging.h"
 
 
@@ -21,7 +22,7 @@ void PrepareDBus()
     static constexpr char libname[] = "libdbus-1.so.3";
 
     auto load_func = [](auto &f, const char *name) -> void
-    { f = reinterpret_cast<std::remove_reference_t<decltype(f)>>(GetSymbol(dbus_handle, name)); };
+    { f = al::bit_cast<std::remove_reference_t<decltype(f)>>(GetSymbol(dbus_handle, name)); };
 #define LOAD_FUNC(x) do {                         \
     load_func(p##x, #x);                          \
     if(!p##x)                                     \