Revise bypass mode in SpatialDecApplyParameterSets() to prevent an assert in fDivNorm().

Bug: 176246647
Test: atest android.media.cts.DecoderTestAacFormat android.media.cts.DecoderTestXheAac android.media.cts.DecoderTestAacDrc
Change-Id: I198747688f1677b82f27a17a2fcf40229c92b1da

libSACdec/src/sac_dec.cpp

@@ -1,7 +1,7 @@
 /* -----------------------------------------------------------------------------
 Software License for The Fraunhofer FDK AAC Codec Library for Android
 
-© Copyright  1995 - 2019 Fraunhofer-Gesellschaft zur Förderung der angewandten
+© Copyright  1995 - 2020 Fraunhofer-Gesellschaft zur Förderung der angewandten
 Forschung e.V. All rights reserved.
 
  1.    INTRODUCTION
@@ -1098,6 +1098,28 @@ static void SpatialDecApplyBypass(spatialDec *self, FIXP_DBL **hybInputReal,
   }
 }
 
+/**
+ * \brief Set internal error and reset error status
+ *
+ * \param self         spatialDec handle.
+ * \param bypassMode   pointer to bypassMode.
+ * \param err          error status.
+ *
+ * \return  error status.
+ */
+static SACDEC_ERROR SpatialDecSetInternalError(spatialDec *self,
+                                               int *bypassMode,
+                                               SACDEC_ERROR err) {
+  *bypassMode = 1;
+
+  if (self->errInt == MPS_OK) {
+    /* store internal error before it gets overwritten */
+    self->errInt = err;
+  }
+
+  return MPS_OK;
+}
+
 /*******************************************************************************
  Functionname: SpatialDecApplyParameterSets
  *******************************************************************************
@@ -1118,7 +1140,7 @@ static SACDEC_ERROR SpatialDecApplyParameterSets(
     const FDK_channelMapDescr *const mapDescr) {
   SACDEC_ERROR err = MPS_OK;
 
-  FIXP_SGL alpha;
+  FIXP_SGL alpha = FL2FXCONST_SGL(0.0);
 
   int ts;
   int ch;
@@ -1141,20 +1163,22 @@ static SACDEC_ERROR SpatialDecApplyParameterSets(
        ts++, ts_io++) {
     int currSlot = frame->paramSlot[ps];
 
+    err = (currSlot < ts) ? MPS_WRONG_PARAMETERSETS : MPS_OK;
+    if (err != MPS_OK) {
+      err = SpatialDecSetInternalError(self, &bypassMode, err);
+    }
+
     /*
      * Get new parameter set
      */
     if (ts == prevSlot + 1) {
-      err = SpatialDecCalculateM1andM2(self, ps,
+      if (bypassMode == 0) {
-                                       frame); /* input: ottCLD, ottICC, ... */
+        err = SpatialDecCalculateM1andM2(
+            self, ps, frame); /* input: ottCLD, ottICC, ... */
                               /* output: M1param(Real/Imag), M2(Real/Imag) */
         if (err != MPS_OK) {
-        bypassMode = 1;
+          err = SpatialDecSetInternalError(self, &bypassMode, err);
-        if (self->errInt == MPS_OK) {
-          /* store internal error befor it gets overwritten */
-          self->errInt = err;
         }
-        err = MPS_OK;
       }
 
       if ((ps == 0) && (self->bOverwriteM1M2prev != 0)) {
@@ -1168,13 +1192,16 @@ static SACDEC_ERROR SpatialDecApplyParameterSets(
         self->bOverwriteM1M2prev = 0;
       }
 
+      if (bypassMode == 0) {
         SpatialDecSmoothM1andM2(
             self, frame,
             ps); /* input: M1param(Real/Imag)(Prev), M2(Real/Imag)(Prev) */
-               /* output: M1param(Real/Imag), M2(Real/Imag) */
+      }          /* output: M1param(Real/Imag), M2(Real/Imag) */
     }
 
+    if (bypassMode == 0) {
       alpha = FX_DBL2FX_SGL(fDivNorm(ts - prevSlot, currSlot - prevSlot));
+    }
 
     switch (mode) {
       case INPUTMODE_QMF_SBR:
@@ -1360,7 +1387,7 @@ static SACDEC_ERROR SpatialDecApplyParameterSets(
       }   /* !self->tempShapeConfig == 1 */
     }     /*  !bypassMode */
 
-    if (self->phaseCoding == 1) {
+    if ((self->phaseCoding == 1) && (bypassMode == 0)) {
       /* only if bsPhaseCoding == 1 and bsResidualCoding == 0 */
 
       SpatialDecApplyPhase(