Update a ton of audio code to use size_t more correctly and in general reduce

webrtc/modules/audio_processing/intelligibility/intelligibility_enhancer.cc

Index: webrtc/modules/audio_processing/intelligibility/intelligibility_enhancer.cc
diff --git a/webrtc/modules/audio_processing/intelligibility/intelligibility_enhancer.cc b/webrtc/modules/audio_processing/intelligibility/intelligibility_enhancer.cc
index 8eccde452c359cd49c0a29096a1cfc9628b261a7..33ff5cda8712f3bdce60a45205f120447bb534ce 100644
--- a/webrtc/modules/audio_processing/intelligibility/intelligibility_enhancer.cc
+++ b/webrtc/modules/audio_processing/intelligibility/intelligibility_enhancer.cc
@@ -30,7 +30,7 @@ namespace webrtc {
 
 namespace {
 
-const int kErbResolution = 2;
+const size_t kErbResolution = 2;
 const int kWindowSizeMs = 2;
 const int kChunkSizeMs = 10;  // Size provided by APM.
 const float kClipFreq = 200.0f;
@@ -55,7 +55,7 @@ IntelligibilityEnhancer::TransformCallback::TransformCallback(
 void IntelligibilityEnhancer::TransformCallback::ProcessAudioBlock(
     const complex<float>* const* in_block,
     int in_channels,
-    int frames,
+    size_t frames,
     int /* out_channels */,
     complex<float>* const* out_block) {
   DCHECK_EQ(parent_->freqs_, frames);
@@ -71,8 +71,9 @@ IntelligibilityEnhancer::IntelligibilityEnhancer()
 IntelligibilityEnhancer::IntelligibilityEnhancer(const Config& config)
     : freqs_(RealFourier::ComplexLength(
           RealFourier::FftOrder(config.sample_rate_hz * kWindowSizeMs / 1000))),
-      window_size_(1 << RealFourier::FftOrder(freqs_)),
-      chunk_length_(config.sample_rate_hz * kChunkSizeMs / 1000),
+      window_size_(static_cast<size_t>(1 << RealFourier::FftOrder(freqs_))),
+      chunk_length_(
+          static_cast<size_t>(config.sample_rate_hz * kChunkSizeMs / 1000)),
       bank_size_(GetBankSize(config.sample_rate_hz, kErbResolution)),
       sample_rate_hz_(config.sample_rate_hz),
       erb_resolution_(kErbResolution),
@@ -107,14 +108,14 @@ IntelligibilityEnhancer::IntelligibilityEnhancer(const Config& config)
   CreateErbBank();
 
   // Assumes all rho equal.
-  for (int i = 0; i < bank_size_; ++i) {
+  for (size_t i = 0; i < bank_size_; ++i) {
     rho_[i] = config.rho * config.rho;
   }
 
   float freqs_khz = kClipFreq / 1000.0f;
-  int erb_index = static_cast<int>(ceilf(
+  size_t erb_index = static_cast<size_t>(ceilf(
       11.17f * logf((freqs_khz + 0.312f) / (freqs_khz + 14.6575f)) + 43.0f));
-  start_freq_ = max(1, erb_index * erb_resolution_);
+  start_freq_ = std::max(static_cast<size_t>(1), erb_index * erb_resolution_);
 
   WindowGenerator::KaiserBesselDerived(kKbdAlpha, window_size_,
                                        kbd_window_.get());
@@ -238,9 +239,9 @@ void IntelligibilityEnhancer::SolveForLambda(float power_target,
 void IntelligibilityEnhancer::UpdateErbGains() {
   // (ERB gain) = filterbank' * (freq gain)
   float* gains = gain_applier_.target();
-  for (int i = 0; i < freqs_; ++i) {
+  for (size_t i = 0; i < freqs_; ++i) {
     gains[i] = 0.0f;
-    for (int j = 0; j < bank_size_; ++j) {
+    for (size_t j = 0; j < bank_size_; ++j) {
       gains[i] = fmaf(filter_bank_[j][i], gains_eq_[j], gains[i]);
     }
   }
@@ -251,90 +252,95 @@ void IntelligibilityEnhancer::ProcessNoiseBlock(const complex<float>* in_block,
   noise_variance_.Step(in_block);
 }
 
-int IntelligibilityEnhancer::GetBankSize(int sample_rate, int erb_resolution) {
+size_t IntelligibilityEnhancer::GetBankSize(int sample_rate,
+                                            size_t erb_resolution) {
   float freq_limit = sample_rate / 2000.0f;
-  int erb_scale = ceilf(
-      11.17f * logf((freq_limit + 0.312f) / (freq_limit + 14.6575f)) + 43.0f);
+  size_t erb_scale = static_cast<size_t>(ceilf(
+      11.17f * logf((freq_limit + 0.312f) / (freq_limit + 14.6575f)) + 43.0f));
   return erb_scale * erb_resolution;
 }
 
 void IntelligibilityEnhancer::CreateErbBank() {
-  int lf = 1, rf = 4;
+  size_t lf = 1, rf = 4;
 
-  for (int i = 0; i < bank_size_; ++i) {
+  for (size_t i = 0; i < bank_size_; ++i) {
     float abs_temp = fabsf((i + 1.0f) / static_cast<float>(erb_resolution_));
     center_freqs_[i] = 676170.4f / (47.06538f - expf(0.08950404f * abs_temp));
     center_freqs_[i] -= 14678.49f;
   }
   float last_center_freq = center_freqs_[bank_size_ - 1];
-  for (int i = 0; i < bank_size_; ++i) {
+  for (size_t i = 0; i < bank_size_; ++i) {
     center_freqs_[i] *= 0.5f * sample_rate_hz_ / last_center_freq;
   }
 
-  for (int i = 0; i < bank_size_; ++i) {
+  for (size_t i = 0; i < bank_size_; ++i) {
     filter_bank_[i].resize(freqs_);
   }
 
-  for (int i = 1; i <= bank_size_; ++i) {
-    int lll, ll, rr, rrr;
-    lll = round(center_freqs_[max(1, i - lf) - 1] * freqs_ /
-                (0.5f * sample_rate_hz_));
-    ll =
-        round(center_freqs_[max(1, i) - 1] * freqs_ / (0.5f * sample_rate_hz_));
-    lll = min(freqs_, max(lll, 1)) - 1;
-    ll = min(freqs_, max(ll, 1)) - 1;
-
-    rrr = round(center_freqs_[min(bank_size_, i + rf) - 1] * freqs_ /
-                (0.5f * sample_rate_hz_));
-    rr = round(center_freqs_[min(bank_size_, i + 1) - 1] * freqs_ /
-               (0.5f * sample_rate_hz_));
-    rrr = min(freqs_, max(rrr, 1)) - 1;
-    rr = min(freqs_, max(rr, 1)) - 1;
+  for (size_t i = 1; i <= bank_size_; ++i) {
+    size_t lll, ll, rr, rrr;
+    static const size_t kOne = 1;  // Avoids repeated static_cast<>s below.
+    lll = static_cast<size_t>(round(
+        center_freqs_[max(kOne, i - lf) - 1] * freqs_ /
+            (0.5f * sample_rate_hz_)));
+    ll = static_cast<size_t>(round(
+        center_freqs_[max(kOne, i) - 1] * freqs_ / (0.5f * sample_rate_hz_)));
+    lll = min(freqs_, max(lll, kOne)) - 1;
+    ll = min(freqs_, max(ll, kOne)) - 1;
+
+    rrr = static_cast<size_t>(round(
+        center_freqs_[min(bank_size_, i + rf) - 1] * freqs_ /
+            (0.5f * sample_rate_hz_)));
+    rr = static_cast<size_t>(round(
+        center_freqs_[min(bank_size_, i + 1) - 1] * freqs_ /
+            (0.5f * sample_rate_hz_)));
+    rrr = min(freqs_, max(rrr, kOne)) - 1;
+    rr = min(freqs_, max(rr, kOne)) - 1;
 
     float step, element;
 
     step = 1.0f / (ll - lll);
     element = 0.0f;
-    for (int j = lll; j <= ll; ++j) {
+    for (size_t j = lll; j <= ll; ++j) {
       filter_bank_[i - 1][j] = element;
       element += step;
     }
     step = 1.0f / (rrr - rr);
     element = 1.0f;
-    for (int j = rr; j <= rrr; ++j) {
+    for (size_t j = rr; j <= rrr; ++j) {
       filter_bank_[i - 1][j] = element;
       element -= step;
     }
-    for (int j = ll; j <= rr; ++j) {
+    for (size_t j = ll; j <= rr; ++j) {
       filter_bank_[i - 1][j] = 1.0f;
     }
   }
 
   float sum;
-  for (int i = 0; i < freqs_; ++i) {
+  for (size_t i = 0; i < freqs_; ++i) {
     sum = 0.0f;
-    for (int j = 0; j < bank_size_; ++j) {
+    for (size_t j = 0; j < bank_size_; ++j) {
       sum += filter_bank_[j][i];
     }
-    for (int j = 0; j < bank_size_; ++j) {
+    for (size_t j = 0; j < bank_size_; ++j) {
       filter_bank_[j][i] /= sum;
     }
   }
 }
 
 void IntelligibilityEnhancer::SolveForGainsGivenLambda(float lambda,
-                                                       int start_freq,
+                                                       size_t start_freq,
                                                        float* sols) {
   bool quadratic = (kConfigRho < 1.0f);
   const float* var_x0 = filtered_clear_var_.get();
   const float* var_n0 = filtered_noise_var_.get();
 
-  for (int n = 0; n < start_freq; ++n) {
+  for (size_t n = 0; n < start_freq; ++n) {
     sols[n] = 1.0f;
   }
 
   // Analytic solution for optimal gains. See paper for derivation.
-  for (int n = start_freq - 1; n < bank_size_; ++n) {
+  for (size_t n = start_freq - 1; n < bank_size_; ++n) {
     float alpha0, beta0, gamma0;
     gamma0 = 0.5f * rho_[n] * var_x0[n] * var_n0[n] +
              lambda * var_x0[n] * var_n0[n] * var_n0[n];
@@ -351,18 +357,18 @@ void IntelligibilityEnhancer::SolveForGainsGivenLambda(float lambda,
 }
 
 void IntelligibilityEnhancer::FilterVariance(const float* var, float* result) {
-  DCHECK_GT(freqs_, 0);
-  for (int i = 0; i < bank_size_; ++i) {
+  DCHECK_GT(freqs_, 0u);
+  for (size_t i = 0; i < bank_size_; ++i) {
     result[i] = DotProduct(&filter_bank_[i][0], var, freqs_);
   }
 }
 
 float IntelligibilityEnhancer::DotProduct(const float* a,
                                           const float* b,
-                                          int length) {
+                                          size_t length) {
   float ret = 0.0f;
 
-  for (int i = 0; i < length; ++i) {
+  for (size_t i = 0; i < length; ++i) {
     ret = fmaf(a[i], b[i], ret);
   }
   return ret;