fix undefined behavior: left shift a negative integer

C/C++ leaves left-shifting a negative integer up to the compiler
implementation.

On most platforms, left-shifting a negative integer is the same as
casting to the unsigned equivalent, then casting back into the signed
type.

This replaces the left-shift with the mathematical equivalent and avoids
the undefined behavior.

Ideally this should be performed for any case of left-shifting a signed
type, but this commit only covers cases picked up by the undefined
behavior sanitizer.

src/app/basicWavReader.cpp

@@ -277,7 +277,7 @@ unsigned BasicWavReader::readDataLnPcm16 (const int fileHandle, int32_t* frameBu
 
     for (unsigned i = read * chanCount; i > 0; i--)
     {
-      *(frameBuf++) = (int32_t) *(iBuf++) << 8; // * 2^8
+      *(frameBuf++) = (int32_t) *(iBuf++) * (1 << 8); // * 2^8
     }
     framesRead += read;
   }

src/app/exhaleAppPch.cpp

@@ -28,7 +28,7 @@ void eaExtrapolate (int32_t* const pcmBuffer, const uint16_t pcmOffset, // start
   for (uint16_t ch = 0; ch < numChannels; ch++)
   {
     int32_t* chPcmBuf = pcmBuffer + ch + (pcmOffset - (fadeIn ? 0 : 1)) * numChannels;
-    int32_t  result32 = (pcmOffset == 0 ? 0 : *chPcmBuf << 8); // input is known to be 24-bit PCM
+    int32_t  result32 = (pcmOffset == 0 ? 0 : *chPcmBuf * (1 << 8)); // input is known to be 24-bit PCM
     const int32_t s32 = result32 / size;
 
     for (uint16_t i = size; i > 0; i--) *(chPcmBuf += delta) = ((result32 -= s32) + 128) >> 8;

src/app/loudnessEstim.cpp

@@ -80,7 +80,7 @@ uint32_t LoudnessEstimator::addNewPcmData (const unsigned samplesPerChannel)
         const int64_t pi = filtI[0] * i[0] + filtI[1] * i[1] + filtI[2] * i[2] + filtI[3] * i[3] -
                            filtO[0] * o[0] - filtO[1] * o[1] - filtO[2] * o[2] - filtO[3] * o[3];
         const int64_t to = (pi < 0 ? (1 << 28) - 1 : 0); // trunc. offset
-        const int32_t xi = (*(chSig++)) << 2;
+        const int32_t xi = (*(chSig++)) * (1 << 2);
         const int32_t yi = xi + int32_t ((pi + (xi == 0 ? to : (1 << 27))) >> 28);
         const uint32_t a = abs (xi >> 2);
 

src/lib/linearPrediction.cpp

@@ -190,8 +190,8 @@ uint32_t LinearPredictor::calcParCorCoeffs (const int32_t* const anaSignal, cons
       for (p = s; p < nCoeffs; p++)
       {
         sampleHO  =  EN[p - s]; // use register?
-        EN[p - s] = (EN[p - s] << 9) + EP[p] * Ks;
-        EP[p]     = (EP[p] << 9)  + sampleHO * Ks;
+        EN[p - s] = (EN[p - s] * (1 << 9)) + EP[p] * Ks;
+        EP[p]     = (EP[p] * (1 << 9))  + sampleHO * Ks;
       }
       if (s > 0 && EN[0] < 0)  // EN wrap-around
       {
@@ -255,11 +255,11 @@ uint8_t LinearPredictor::calcOptTnsCoeffs (short* const parCorCoeffs, int8_t* co
   }
 
   // determine direct-form filter damping factor
-  parCorCoeffs[0] <<= bitShift;
+  parCorCoeffs[0] *= 1 << bitShift;
   i = abs (parCorCoeffs[0]);
   for (s = 1; s < order; s++)
   {
-    parCorCoeffs[s] <<= bitShift; // scale coeff
+    parCorCoeffs[s] *= 1 << bitShift; // scale coeff
     i = __max (i, abs (parCorCoeffs[s]));
   }
   for (/*s*/; s < MAX_PREDICTION_ORDER; s++)
@@ -343,7 +343,7 @@ unsigned LinearPredictor::lpToParCorCoeffs (/*mod!*/short* const lpCoeffs, const
     }
     for (p = 0; p < s; p++)
     {
-      lpCoeffs[p] = short ((o + ((int) lpCoeffs[p] << shift) - intBuf[p] * i) / d);
+      lpCoeffs[p] = short ((o + ((int) lpCoeffs[p] * (1 << shift)) - intBuf[p] * i) / d);
     }
   }
   parCorCoeffs[0] = lpCoeffs[0];

src/lib/specGapFilling.cpp

@@ -268,7 +268,7 @@ uint8_t SpecGapFiller::getSpecGapFillParams (const SfbQuantizer& sfbQuantizer, c
       {
         unsigned countOld = 0, countNew = 0;
 
-        b = CLIP_PM (((b << 8) + (a >> 1)) / a, SHRT_MAX);
+        b = CLIP_PM (((b * (1 << 8)) + (a >> 1)) / a, SHRT_MAX);
         a = ((ySum << 8) - b * xSum + (size >> 1)) / size;
 
         ySum = grpScFacs[start];

src/lib/tempAnalysis.cpp

@@ -210,7 +210,7 @@ unsigned TempAnalyzer::temporalAnalysis (const int32_t* const timeSignals[USAC_M
 
       for (int i = nSamplesInFrame >> sbrShift; i > 0; i--, lrSig++, hrSig += 2)
       {
-        int64_t r  = ((int64_t) hrSig[0] << 17) + (hrSig[-1] + (int64_t) hrSig[1]) * -2*SHRT_MIN;
+        int64_t r  = ((int64_t) hrSig[0] * (1 << 17)) + (hrSig[-1] + (int64_t) hrSig[1]) * -2*SHRT_MIN;
         int16_t s;
 
         for (u = 65, s = 129; u > 0; s -= 2) r += (hrSig[-s] + (int64_t) hrSig[s]) * lpfc12[--u];
@@ -222,7 +222,7 @@ unsigned TempAnalyzer::temporalAnalysis (const int32_t* const timeSignals[USAC_M
 
         if ((i & 1) != 0) // compute quarter-rate mid-frequency SBR signal
         {
-          r  = ((3 * (int64_t) hrSig[0]) << 16) - (hrSig[-1] + (int64_t) hrSig[1]) * SHRT_MIN - r;
+          r  = ((3 * (int64_t) hrSig[0]) * (1 << 16)) - (hrSig[-1] + (int64_t) hrSig[1]) * SHRT_MIN - r;
           r += (hrSig[-2] + (int64_t) hrSig[2]) * SHRT_MIN;
 
           for (s = 127; s > 0; s--/*u = s*/) r += (hrSig[-s] + (int64_t) hrSig[s]) * lpfc34[s];