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

webrtc/modules/audio_processing/vad/pole_zero_filter.cc

 /*
  *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
 #include "webrtc/modules/audio_processing/vad/pole_zero_filter.h"
 
 #include <stdlib.h>
 #include <string.h>
 #include <algorithm>
 
 namespace webrtc {
 
 PoleZeroFilter* PoleZeroFilter::Create(const float* numerator_coefficients,
-                                       int order_numerator,
+                                       size_t order_numerator,
                                        const float* denominator_coefficients,
-                                       int order_denominator) {
-  if (order_numerator < 0 || order_denominator < 0 ||
-      order_numerator > kMaxFilterOrder ||
+                                       size_t order_denominator) {
+  if (order_numerator > kMaxFilterOrder ||
       order_denominator > kMaxFilterOrder || denominator_coefficients[0] == 0 ||
       numerator_coefficients == NULL || denominator_coefficients == NULL)
     return NULL;
   return new PoleZeroFilter(numerator_coefficients, order_numerator,
                             denominator_coefficients, order_denominator);
 }
 
 PoleZeroFilter::PoleZeroFilter(const float* numerator_coefficients,
-                               int order_numerator,
+                               size_t order_numerator,
                                const float* denominator_coefficients,
-                               int order_denominator)
+                               size_t order_denominator)
     : past_input_(),
       past_output_(),
       numerator_coefficients_(),
       denominator_coefficients_(),
       order_numerator_(order_numerator),
       order_denominator_(order_denominator),
       highest_order_(std::max(order_denominator, order_numerator)) {
   memcpy(numerator_coefficients_, numerator_coefficients,
          sizeof(numerator_coefficients_[0]) * (order_numerator_ + 1));
   memcpy(denominator_coefficients_, denominator_coefficients,
          sizeof(denominator_coefficients_[0]) * (order_denominator_ + 1));
 
   if (denominator_coefficients_[0] != 1) {
-    for (int n = 0; n <= order_numerator_; n++)
+    for (size_t n = 0; n <= order_numerator_; n++)
       numerator_coefficients_[n] /= denominator_coefficients_[0];
-    for (int n = 0; n <= order_denominator_; n++)
+    for (size_t n = 0; n <= order_denominator_; n++)
       denominator_coefficients_[n] /= denominator_coefficients_[0];
   }
 }
 
 template <typename T>
-static float FilterArPast(const T* past, int order, const float* coefficients) {
+static float FilterArPast(const T* past, size_t order,
+                          const float* coefficients) {
   float sum = 0.0f;
-  int past_index = order - 1;
-  for (int k = 1; k <= order; k++, past_index--)
+  size_t past_index = order - 1;
+  for (size_t k = 1; k <= order; k++, past_index--)
     sum += coefficients[k] * past[past_index];
   return sum;
 }
 
 int PoleZeroFilter::Filter(const int16_t* in,
-                           int num_input_samples,
+                           size_t num_input_samples,
                            float* output) {
-  if (in == NULL || num_input_samples < 0 || output == NULL)
+  if (in == NULL || output == NULL)
     return -1;
   // This is the typical case, just a memcpy.
-  const int k = std::min(num_input_samples, highest_order_);
-  int n;
+  const size_t k = std::min(num_input_samples, highest_order_);
+  size_t n;
   for (n = 0; n < k; n++) {
     output[n] = in[n] * numerator_coefficients_[0];
     output[n] += FilterArPast(&past_input_[n], order_numerator_,
                               numerator_coefficients_);
     output[n] -= FilterArPast(&past_output_[n], order_denominator_,
                               denominator_coefficients_);
 
     past_input_[n + order_numerator_] = in[n];
     past_output_[n + order_denominator_] = output[n];
   }
   if (highest_order_ < num_input_samples) {
-    for (int m = 0; n < num_input_samples; n++, m++) {
+    for (size_t m = 0; n < num_input_samples; n++, m++) {
       output[n] = in[n] * numerator_coefficients_[0];
       output[n] +=
           FilterArPast(&in[m], order_numerator_, numerator_coefficients_);
       output[n] -= FilterArPast(&output[m], order_denominator_,
                                 denominator_coefficients_);
     }
     // Record into the past signal.
     memcpy(past_input_, &in[num_input_samples - order_numerator_],
            sizeof(in[0]) * order_numerator_);
     memcpy(past_output_, &output[num_input_samples - order_denominator_],
            sizeof(output[0]) * order_denominator_);
   } else {
     // Odd case that the length of the input is shorter that filter order.
     memmove(past_input_, &past_input_[num_input_samples],
             order_numerator_ * sizeof(past_input_[0]));
     memmove(past_output_, &past_output_[num_input_samples],
             order_denominator_ * sizeof(past_output_[0]));
   }
   return 0;
 }
 
 }  // namespace webrtc