Make some pointer-to-array parameters const

Alc/ALu.c

@@ -1489,10 +1489,9 @@ ALvoid aluMixData(ALCdevice *device, ALvoid *buffer, ALsizei size)
             slot = slotroot;
             while(slot)
             {
-                const ALeffectslot *cslot = slot;
-                ALeffectState *state = cslot->Params.EffectState;
-                V(state,process)(SamplesToDo, cslot->WetBuffer, state->OutBuffer,
-                                 state->OutChannels);
+                ALeffectState *state = slot->Params.EffectState;
+                V(state,process)(SamplesToDo, SAFE_CONST(ALfloatBUFFERSIZE*,slot->WetBuffer),
+                                 state->OutBuffer, state->OutChannels);
                 slot = ATOMIC_LOAD(&slot->next, almemory_order_relaxed);
             }
 
@@ -1540,19 +1539,19 @@ ALvoid aluMixData(ALCdevice *device, ALvoid *buffer, ALsizei size)
         {
             if(device->Dry.Buffer != device->FOAOut.Buffer)
                 bformatdec_upSample(device->AmbiDecoder,
-                    device->Dry.Buffer, device->FOAOut.Buffer,
+                    device->Dry.Buffer, SAFE_CONST(ALfloatBUFFERSIZE*,device->FOAOut.Buffer),
                     device->FOAOut.NumChannels, SamplesToDo
                 );
             bformatdec_process(device->AmbiDecoder,
                 device->RealOut.Buffer, device->RealOut.NumChannels,
-                device->Dry.Buffer, SamplesToDo
+                SAFE_CONST(ALfloatBUFFERSIZE*,device->Dry.Buffer), SamplesToDo
             );
         }
         else if(device->AmbiUp)
         {
             ambiup_process(device->AmbiUp,
                 device->RealOut.Buffer, device->RealOut.NumChannels,
-                device->FOAOut.Buffer, SamplesToDo
+                SAFE_CONST(ALfloatBUFFERSIZE*,device->FOAOut.Buffer), SamplesToDo
             );
         }
         else if(device->Uhj_Encoder)

Alc/bformatdec.c

@@ -161,19 +161,6 @@ static const ALfloat Ambi3DDecoder[8][FB_Max][MAX_AMBI_COEFFS] = {
 static ALfloat Ambi3DEncoder[8][MAX_AMBI_COEFFS];
 
 
-static inline RowMixerFunc SelectRowMixer(void)
-{
-#ifdef HAVE_SSE
-    if((CPUCapFlags&CPU_CAP_SSE))
-        return MixRow_SSE;
-#endif
-#ifdef HAVE_NEON
-    if((CPUCapFlags&CPU_CAP_NEON))
-        return MixRow_Neon;
-#endif
-    return MixRow_C;
-}
-
 static RowMixerFunc MixMatrixRow = MixRow_C;
 
 
@@ -495,7 +482,7 @@ void bformatdec_reset(BFormatDec *dec, const AmbDecConf *conf, ALuint chancount,
 }
 
 
-void bformatdec_process(struct BFormatDec *dec, ALfloat (*restrict OutBuffer)[BUFFERSIZE], ALuint OutChannels, ALfloat (*restrict InSamples)[BUFFERSIZE], ALuint SamplesToDo)
+void bformatdec_process(struct BFormatDec *dec, ALfloat (*restrict OutBuffer)[BUFFERSIZE], ALuint OutChannels, const ALfloat (*restrict InSamples)[BUFFERSIZE], ALuint SamplesToDo)
 {
     ALuint chan, i;
 
@@ -512,10 +499,12 @@ void bformatdec_process(struct BFormatDec *dec, ALfloat (*restrict OutBuffer)[BU
 
             memset(dec->ChannelMix, 0, SamplesToDo*sizeof(ALfloat));
             MixMatrixRow(dec->ChannelMix, dec->Matrix.Dual[chan][FB_HighFreq],
-                dec->SamplesHF, dec->NumChannels, SamplesToDo
+                SAFE_CONST(ALfloatBUFFERSIZE*,dec->SamplesHF), dec->NumChannels, 0,
+                SamplesToDo
             );
             MixMatrixRow(dec->ChannelMix, dec->Matrix.Dual[chan][FB_LowFreq],
-                dec->SamplesLF, dec->NumChannels, SamplesToDo
+                SAFE_CONST(ALfloatBUFFERSIZE*,dec->SamplesLF), dec->NumChannels, 0,
+                SamplesToDo
             );
 
             if(dec->Delay[chan].Length > 0)
@@ -553,7 +542,7 @@ void bformatdec_process(struct BFormatDec *dec, ALfloat (*restrict OutBuffer)[BU
 
             memset(dec->ChannelMix, 0, SamplesToDo*sizeof(ALfloat));
             MixMatrixRow(dec->ChannelMix, dec->Matrix.Single[chan], InSamples,
-                         dec->NumChannels, SamplesToDo);
+                         dec->NumChannels, 0, SamplesToDo);
 
             if(dec->Delay[chan].Length > 0)
             {
@@ -584,7 +573,7 @@ void bformatdec_process(struct BFormatDec *dec, ALfloat (*restrict OutBuffer)[BU
 }
 
 
-void bformatdec_upSample(struct BFormatDec *dec, ALfloat (*restrict OutBuffer)[BUFFERSIZE], ALfloat (*restrict InSamples)[BUFFERSIZE], ALuint InChannels, ALuint SamplesToDo)
+void bformatdec_upSample(struct BFormatDec *dec, ALfloat (*restrict OutBuffer)[BUFFERSIZE], const ALfloat (*restrict InSamples)[BUFFERSIZE], ALuint InChannels, ALuint SamplesToDo)
 {
     ALuint i, j;
 
@@ -608,7 +597,9 @@ void bformatdec_upSample(struct BFormatDec *dec, ALfloat (*restrict OutBuffer)[B
         /* Now write each band to the output. */
         for(j = 0;j < dec->NumChannels;j++)
             MixMatrixRow(OutBuffer[j], dec->UpSampler.Gains[i][j],
-                         dec->Samples, FB_Max, SamplesToDo);
+                SAFE_CONST(ALfloatBUFFERSIZE*,dec->Samples), FB_Max, 0,
+                SamplesToDo
+            );
     }
 }
 
@@ -659,7 +650,7 @@ void ambiup_reset(struct AmbiUpsampler *ambiup, const ALCdevice *device)
     }
 }
 
-void ambiup_process(struct AmbiUpsampler *ambiup, ALfloat (*restrict OutBuffer)[BUFFERSIZE], ALuint OutChannels, ALfloat (*restrict InSamples)[BUFFERSIZE], ALuint SamplesToDo)
+void ambiup_process(struct AmbiUpsampler *ambiup, ALfloat (*restrict OutBuffer)[BUFFERSIZE], ALuint OutChannels, const ALfloat (*restrict InSamples)[BUFFERSIZE], ALuint SamplesToDo)
 {
     ALuint i, j;
 
@@ -672,6 +663,8 @@ void ambiup_process(struct AmbiUpsampler *ambiup, ALfloat (*restrict OutBuffer)[
 
         for(j = 0;j < OutChannels;j++)
             MixMatrixRow(OutBuffer[j], ambiup->Gains[i][j],
-                         ambiup->Samples, FB_Max, SamplesToDo);
+                SAFE_CONST(ALfloatBUFFERSIZE*,ambiup->Samples), FB_Max, 0,
+                SamplesToDo
+            );
     }
 }

Alc/bformatdec.h

@@ -17,10 +17,10 @@ int bformatdec_getOrder(const struct BFormatDec *dec);
 void bformatdec_reset(struct BFormatDec *dec, const struct AmbDecConf *conf, ALuint chancount, ALuint srate, const ALuint chanmap[MAX_OUTPUT_CHANNELS], int flags);
 
 /* Decodes the ambisonic input to the given output channels. */
-void bformatdec_process(struct BFormatDec *dec, ALfloat (*restrict OutBuffer)[BUFFERSIZE], ALuint OutChannels, ALfloat (*restrict InSamples)[BUFFERSIZE], ALuint SamplesToDo);
+void bformatdec_process(struct BFormatDec *dec, ALfloat (*restrict OutBuffer)[BUFFERSIZE], ALuint OutChannels, const ALfloat (*restrict InSamples)[BUFFERSIZE], ALuint SamplesToDo);
 
 /* Up-samples a first-order input to the decoder's configuration. */
-void bformatdec_upSample(struct BFormatDec *dec, ALfloat (*restrict OutBuffer)[BUFFERSIZE], ALfloat (*restrict InSamples)[BUFFERSIZE], ALuint InChannels, ALuint SamplesToDo);
+void bformatdec_upSample(struct BFormatDec *dec, ALfloat (*restrict OutBuffer)[BUFFERSIZE], const ALfloat (*restrict InSamples)[BUFFERSIZE], ALuint InChannels, ALuint SamplesToDo);
 
 
 /* Stand-alone first-order upsampler. Kept here because it shares some stuff
@@ -30,7 +30,7 @@ struct AmbiUpsampler *ambiup_alloc();
 void ambiup_free(struct AmbiUpsampler *ambiup);
 void ambiup_reset(struct AmbiUpsampler *ambiup, const ALCdevice *device);
 
-void ambiup_process(struct AmbiUpsampler *ambiup, ALfloat (*restrict OutBuffer)[BUFFERSIZE], ALuint OutChannels, ALfloat (*restrict InSamples)[BUFFERSIZE], ALuint SamplesToDo);
+void ambiup_process(struct AmbiUpsampler *ambiup, ALfloat (*restrict OutBuffer)[BUFFERSIZE], ALuint OutChannels, const ALfloat (*restrict InSamples)[BUFFERSIZE], ALuint SamplesToDo);
 
 
 /* Band splitter. Splits a signal into two phase-matching frequency bands. */

Alc/mixer.c

@@ -79,6 +79,19 @@ MixerFunc SelectMixer(void)
     return Mix_C;
 }
 
+RowMixerFunc SelectRowMixer(void)
+{
+#ifdef HAVE_SSE
+    if((CPUCapFlags&CPU_CAP_SSE))
+        return MixRow_SSE;
+#endif
+#ifdef HAVE_NEON
+    if((CPUCapFlags&CPU_CAP_NEON))
+        return MixRow_Neon;
+#endif
+    return MixRow_C;
+}
+
 static inline HrtfMixerFunc SelectHrtfMixer(void)
 {
 #ifdef HAVE_SSE

Alc/mixer_c.c

@@ -208,7 +208,7 @@ void Mix_C(const ALfloat *data, ALuint OutChans, ALfloat (*restrict OutBuffer)[B
  * transform. And as the matrices are more or less static once set up, no
  * stepping is necessary.
  */
-void MixRow_C(ALfloat *OutBuffer, const ALfloat *Gains, ALfloat (*restrict data)[BUFFERSIZE], ALuint InChans, ALuint BufferSize)
+void MixRow_C(ALfloat *OutBuffer, const ALfloat *Gains, const ALfloat (*restrict data)[BUFFERSIZE], ALuint InChans, ALuint InPos, ALuint BufferSize)
 {
     ALuint c, i;
 
@@ -219,6 +219,6 @@ void MixRow_C(ALfloat *OutBuffer, const ALfloat *Gains, ALfloat (*restrict data)
             continue;
 
         for(i = 0;i < BufferSize;i++)
-            OutBuffer[i] += data[c][i] * gain;
+            OutBuffer[i] += data[c][InPos+i] * gain;
     }
 }

Alc/mixer_defs.h

@@ -31,8 +31,9 @@ void MixDirectHrtf_C(ALfloat (*restrict OutBuffer)[BUFFERSIZE], ALuint lidx, ALu
                      ALuint BufferSize);
 void Mix_C(const ALfloat *data, ALuint OutChans, ALfloat (*restrict OutBuffer)[BUFFERSIZE],
            struct MixGains *Gains, ALuint Counter, ALuint OutPos, ALuint BufferSize);
-void MixRow_C(ALfloat *OutBuffer, const ALfloat *Gains, ALfloat (*restrict data)[BUFFERSIZE],
-              ALuint InChans, ALuint BufferSize);
+void MixRow_C(ALfloat *OutBuffer, const ALfloat *Gains,
+              const ALfloat (*restrict data)[BUFFERSIZE], ALuint InChans,
+              ALuint InPos, ALuint BufferSize);
 
 /* SSE mixers */
 void MixHrtf_SSE(ALfloat (*restrict OutBuffer)[BUFFERSIZE], ALuint lidx, ALuint ridx,
@@ -45,8 +46,9 @@ void MixDirectHrtf_SSE(ALfloat (*restrict OutBuffer)[BUFFERSIZE], ALuint lidx, A
                        ALuint BufferSize);
 void Mix_SSE(const ALfloat *data, ALuint OutChans, ALfloat (*restrict OutBuffer)[BUFFERSIZE],
              struct MixGains *Gains, ALuint Counter, ALuint OutPos, ALuint BufferSize);
-void MixRow_SSE(ALfloat *OutBuffer, const ALfloat *Gains, ALfloat (*restrict data)[BUFFERSIZE],
-                ALuint InChans, ALuint BufferSize);
+void MixRow_SSE(ALfloat *OutBuffer, const ALfloat *Gains,
+                const ALfloat (*restrict data)[BUFFERSIZE], ALuint InChans,
+                ALuint InPos, ALuint BufferSize);
 
 /* SSE resamplers */
 inline void InitiatePositionArrays(ALuint frac, ALuint increment, ALuint *frac_arr, ALuint *pos_arr, ALuint size)
@@ -92,7 +94,8 @@ void MixDirectHrtf_Neon(ALfloat (*restrict OutBuffer)[BUFFERSIZE], ALuint lidx,
                         ALuint BufferSize);
 void Mix_Neon(const ALfloat *data, ALuint OutChans, ALfloat (*restrict OutBuffer)[BUFFERSIZE],
               struct MixGains *Gains, ALuint Counter, ALuint OutPos, ALuint BufferSize);
-void MixRow_Neon(ALfloat *OutBuffer, const ALfloat *Gains, ALfloat (*restrict data)[BUFFERSIZE],
-                 ALuint InChans, ALuint BufferSize);
+void MixRow_Neon(ALfloat *OutBuffer, const ALfloat *Gains,
+                 const ALfloat (*restrict data)[BUFFERSIZE], ALuint InChans,
+                 ALuint InPos, ALuint BufferSize);
 
 #endif /* MIXER_DEFS_H */

Alc/mixer_neon.c

@@ -144,7 +144,7 @@ void Mix_Neon(const ALfloat *data, ALuint OutChans, ALfloat (*restrict OutBuffer
     }
 }
 
-void MixRow_Neon(ALfloat *OutBuffer, const ALfloat *Gains, ALfloat (*restrict data)[BUFFERSIZE], ALuint InChans, ALuint BufferSize)
+void MixRow_Neon(ALfloat *OutBuffer, const ALfloat *Gains, const ALfloat (*restrict data)[BUFFERSIZE], ALuint InChans, ALuint InPos, ALuint BufferSize)
 {
     float32x4_t gain4;
     ALuint c;
@@ -159,12 +159,12 @@ void MixRow_Neon(ALfloat *OutBuffer, const ALfloat *Gains, ALfloat (*restrict da
         gain4 = vdupq_n_f32(gain);
         for(;BufferSize-pos > 3;pos += 4)
         {
-            const float32x4_t val4 = vld1q_f32(&data[c][pos]);
+            const float32x4_t val4 = vld1q_f32(&data[c][InPos+pos]);
             float32x4_t dry4 = vld1q_f32(&OutBuffer[pos]);
             dry4 = vmlaq_f32(dry4, val4, gain4);
             vst1q_f32(&OutBuffer[pos], dry4);
         }
         for(;pos < BufferSize;pos++)
-            OutBuffer[pos] += data[c][pos]*gain;
+            OutBuffer[pos] += data[c][InPos+pos]*gain;
     }
 }

Alc/mixer_sse.c

@@ -262,7 +262,7 @@ void Mix_SSE(const ALfloat *data, ALuint OutChans, ALfloat (*restrict OutBuffer)
     }
 }
 
-void MixRow_SSE(ALfloat *OutBuffer, const ALfloat *Gains, ALfloat (*restrict data)[BUFFERSIZE], ALuint InChans, ALuint BufferSize)
+void MixRow_SSE(ALfloat *OutBuffer, const ALfloat *Gains, const ALfloat (*restrict data)[BUFFERSIZE], ALuint InChans, ALuint InPos, ALuint BufferSize)
 {
     __m128 gain4;
     ALuint c;
@@ -277,12 +277,12 @@ void MixRow_SSE(ALfloat *OutBuffer, const ALfloat *Gains, ALfloat (*restrict dat
         gain4 = _mm_set1_ps(gain);
         for(;BufferSize-pos > 3;pos += 4)
         {
-            const __m128 val4 = _mm_load_ps(&data[c][pos]);
+            const __m128 val4 = _mm_load_ps(&data[c][InPos+pos]);
             __m128 dry4 = _mm_load_ps(&OutBuffer[pos]);
             dry4 = _mm_add_ps(dry4, _mm_mul_ps(val4, gain4));
             _mm_store_ps(&OutBuffer[pos], dry4);
         }
         for(;pos < BufferSize;pos++)
-            OutBuffer[pos] += data[c][pos]*gain;
+            OutBuffer[pos] += data[c][InPos+pos]*gain;
     }
 }

OpenAL32/Include/alMain.h

@@ -128,6 +128,48 @@ AL_API ALboolean AL_APIENTRY alIsBufferFormatSupportedSOFT(ALenum format);
 #endif
 
 
+#ifdef __GNUC__
+/* Because of a long-standing deficiency in C, you're not allowed to implicitly
+ * cast a pointer-to-type-array to a pointer-to-const-type-array. For example,
+ *
+ * int (*ptr)[10];
+ * const int (*cptr)[10] = ptr;
+ *
+ * is not allowed and most compilers will generate noisy warnings about
+ * incompatible types, even though it just makes the array elements const.
+ * Clang will allow it if you make the array type a typedef, like this:
+ *
+ * typedef int int10[10];
+ * int10 *ptr;
+ * const int10 *cptr = ptr;
+ *
+ * however GCC does not and still issues the incompatible type warning. The
+ * "proper" way to fix it is to add an explicit cast for the constified type,
+ * but that removes the vast majority of otherwise useful type-checking you'd
+ * get, and runs the risk of improper casts if types are later changed. Leaving
+ * it non-const can also be an issue if you use it as a function parameter, and
+ * happen to have a const type as input (and also reduce the capabilities of
+ * the compiler to better optimize the function).
+ *
+ * So to work around the problem, we use a macro. The macro first assigns the
+ * incoming variable to the specified non-const type to ensure it's the correct
+ * type, then casts the variable as the desired constified type. Very ugly, but
+ * I'd rather not have hundreds of lines of warnings because I want to tell the
+ * compiler that some array(s) can't be changed by the code, or have lots of
+ * error-prone casts.
+ */
+#define SAFE_CONST(T, var) __extension__({                                    \
+    T _tmp = (var);                                                           \
+    (const T)_tmp;                                                            \
+})
+#else
+/* Non-GNU-compatible compilers have to use a straight cast with no extra
+ * checks, due to the lack of multi-statement expressions.
+ */
+#define SAFE_CONST(T, var) ((const T)(var))
+#endif
+
+
 typedef ALint64SOFT ALint64;
 typedef ALuint64SOFT ALuint64;
 

OpenAL32/Include/alu.h

@@ -162,8 +162,8 @@ typedef void (*MixerFunc)(const ALfloat *data, ALuint OutChans,
                           ALfloat (*restrict OutBuffer)[BUFFERSIZE], struct MixGains *Gains,
                           ALuint Counter, ALuint OutPos, ALuint BufferSize);
 typedef void (*RowMixerFunc)(ALfloat *OutBuffer, const ALfloat *gains,
-                             ALfloat (*restrict data)[BUFFERSIZE], ALuint InChans,
-                             ALuint BufferSize);
+                             const ALfloat (*restrict data)[BUFFERSIZE], ALuint InChans,
+                             ALuint InPos, ALuint BufferSize);
 typedef void (*HrtfMixerFunc)(ALfloat (*restrict OutBuffer)[BUFFERSIZE], ALuint lidx, ALuint ridx,
                               const ALfloat *data, ALuint Counter, ALuint Offset, ALuint OutPos,
                               const ALuint IrSize, const MixHrtfParams *hrtfparams,
@@ -265,6 +265,7 @@ enum HrtfRequestMode {
 void aluInitMixer(void);
 
 MixerFunc SelectMixer(void);
+RowMixerFunc SelectRowMixer(void);
 
 /* aluInitRenderer
  *