From b026a0461d77ee3f58b870dcac0ebc8e2ce02082 Mon Sep 17 00:00:00 2001
From: Ken Cooke <ken@highfidelity.io>
Date: Tue, 10 Oct 2017 09:13:06 -0700
Subject: [PATCH] Fix clang warnings for left-shift of signed int

---
 libraries/audio/src/AudioDynamics.h | 52 ++++++++++++++++-------------
 libraries/audio/src/AudioGate.cpp   | 14 ++++----
 2 files changed, 36 insertions(+), 30 deletions(-)

diff --git a/libraries/audio/src/AudioDynamics.h b/libraries/audio/src/AudioDynamics.h
index b7c168bfab..6f36605025 100644
--- a/libraries/audio/src/AudioDynamics.h
+++ b/libraries/audio/src/AudioDynamics.h
@@ -135,6 +135,7 @@ static const int32_t exp2Table[1 << EXP2_TABBITS][3] = {
 
 static const int IEEE754_FABS_MASK = 0x7fffffff;
 static const int IEEE754_MANT_BITS = 23;
+static const int IEEE754_EXPN_BITS = 8;
 static const int IEEE754_EXPN_BIAS = 127;
 
 //
@@ -152,7 +153,7 @@ static inline int32_t peaklog2(float* input) {
 
     // split into e and x - 1.0
     int32_t e = IEEE754_EXPN_BIAS - (peak >> IEEE754_MANT_BITS) + LOG2_HEADROOM;
-    int32_t x = (peak << (31 - IEEE754_MANT_BITS)) & 0x7fffffff;
+    int32_t x = (peak << IEEE754_EXPN_BITS) & 0x7fffffff;
 
     // saturate
     if (e > 31) {
@@ -191,7 +192,7 @@ static inline int32_t peaklog2(float* input0, float* input1) {
 
     // split into e and x - 1.0
     int32_t e = IEEE754_EXPN_BIAS - (peak >> IEEE754_MANT_BITS) + LOG2_HEADROOM;
-    int32_t x = (peak << (31 - IEEE754_MANT_BITS)) & 0x7fffffff;
+    int32_t x = (peak << IEEE754_EXPN_BITS) & 0x7fffffff;
 
     // saturate
     if (e > 31) {
@@ -234,7 +235,7 @@ static inline int32_t peaklog2(float* input0, float* input1, float* input2, floa
 
     // split into e and x - 1.0
     int32_t e = IEEE754_EXPN_BIAS - (peak >> IEEE754_MANT_BITS) + LOG2_HEADROOM;
-    int32_t x = (peak << (31 - IEEE754_MANT_BITS)) & 0x7fffffff;
+    int32_t x = (peak << IEEE754_EXPN_BITS) & 0x7fffffff;
 
     // saturate
     if (e > 31) {
@@ -259,30 +260,30 @@ static inline int32_t peaklog2(float* input0, float* input1, float* input2, floa
 // Count Leading Zeros
 // Emulates the CLZ (ARM) and LZCNT (x86) instruction
 //
-static inline int CLZ(uint32_t x) {
+static inline int CLZ(uint32_t u) {
 
-    if (x == 0) {
+    if (u == 0) {
         return 32;
     }
 
     int e = 0;
-    if (x < 0x00010000) {
-        x <<= 16;
+    if (u < 0x00010000) {
+        u <<= 16;
         e += 16;
     }
-    if (x < 0x01000000) {
-        x <<= 8;
+    if (u < 0x01000000) {
+        u <<= 8;
         e += 8;
     }
-    if (x < 0x10000000) {
-        x <<= 4;
+    if (u < 0x10000000) {
+        u <<= 4;
         e += 4;
     }
-    if (x < 0x40000000) {
-        x <<= 2;
+    if (u < 0x40000000) {
+        u <<= 2;
         e += 2;
     }
-    if (x < 0x80000000) {
+    if (u < 0x80000000) {
         e += 1;
     }
     return e;
@@ -290,19 +291,19 @@ static inline int CLZ(uint32_t x) {
 
 //
 // Compute -log2(x) for x=[0,1] in Q31, result in Q26
-// x = 0 returns 0x7fffffff
-// x < 0 undefined
+// x <= 0 returns 0x7fffffff
 //
 static inline int32_t fixlog2(int32_t x) {
 
-    if (x == 0) {
+    if (x <= 0) {
         return 0x7fffffff;
     }
 
     // split into e and x - 1.0
-    int e = CLZ((uint32_t)x);
-    x <<= e;            // normalize to [0x80000000, 0xffffffff]
-    x &= 0x7fffffff;    // x - 1.0
+    uint32_t u = (uint32_t)x;
+    int e = CLZ(u);
+    u <<= e;            // normalize to [0x80000000, 0xffffffff]
+    x = u & 0x7fffffff; // x - 1.0
 
     int k = x >> (31 - LOG2_TABBITS);
 
@@ -320,13 +321,18 @@ static inline int32_t fixlog2(int32_t x) {
 
 //
 // Compute exp2(-x) for x=[0,32] in Q26, result in Q31
-// x < 0 undefined
+// x <= 0 returns 0x7fffffff
 //
 static inline int32_t fixexp2(int32_t x) {
 
+    if (x <= 0) {
+        return 0x7fffffff;
+    }
+
     // split into e and 1.0 - x
-    int e = x >> LOG2_FRACBITS;
-    x = ~(x << LOG2_INTBITS) & 0x7fffffff;
+    uint32_t u = (uint32_t)x;
+    int e = u >> LOG2_FRACBITS;
+    x = ~(u << LOG2_INTBITS) & 0x7fffffff;
 
     int k = x >> (31 - EXP2_TABBITS);
 
diff --git a/libraries/audio/src/AudioGate.cpp b/libraries/audio/src/AudioGate.cpp
index ac72533806..5ef5ee25b5 100644
--- a/libraries/audio/src/AudioGate.cpp
+++ b/libraries/audio/src/AudioGate.cpp
@@ -40,7 +40,7 @@ class MonoDCBlock {
 public:
     void process(int32_t& x) {
 
-        x <<= 15;               // scale to Q30
+        x *= (1 << 15);         // scale to Q30
         x -= _dcOffset;         // remove DC
         _dcOffset += x >> 13;   // pole = (1.0 - 2^-13) = 0.9999
     }
@@ -53,8 +53,8 @@ class StereoDCBlock {
 public:
     void process(int32_t& x0, int32_t& x1) {
 
-        x0 <<= 15;
-        x1 <<= 15;
+        x0 *= (1 << 15);
+        x1 *= (1 << 15);
 
         x0 -= _dcOffset[0];
         x1 -= _dcOffset[1];
@@ -71,10 +71,10 @@ class QuadDCBlock {
 public:
     void process(int32_t& x0, int32_t& x1, int32_t& x2, int32_t& x3) {
 
-        x0 <<= 15;
-        x1 <<= 15;
-        x2 <<= 15;
-        x3 <<= 15;
+        x0 *= (1 << 15);
+        x1 *= (1 << 15);
+        x2 *= (1 << 15);
+        x3 *= (1 << 15);
 
         x0 -= _dcOffset[0];
         x1 -= _dcOffset[1];