Make AudioVector::operator[] inline and modify index calculation

webrtc/modules/audio_coding/neteq/audio_vector.h

Index: webrtc/modules/audio_coding/neteq/audio_vector.h
diff --git a/webrtc/modules/audio_coding/neteq/audio_vector.h b/webrtc/modules/audio_coding/neteq/audio_vector.h
index 756292aa783aabd0449bfd76d61a20ade77dca85..18ab95c46d717bdd04a1c0db0557a1d5f90f405a 100644
--- a/webrtc/modules/audio_coding/neteq/audio_vector.h
+++ b/webrtc/modules/audio_coding/neteq/audio_vector.h
@@ -14,6 +14,7 @@
 #include <string.h>  // Access to size_t.
 #include <memory>
 
+#include "webrtc/base/checks.h"
 #include "webrtc/base/constructormagic.h"
 #include "webrtc/typedefs.h"
 
@@ -110,12 +111,30 @@ class AudioVector {
   virtual bool Empty() const;
 
   // Accesses and modifies an element of AudioVector.
-  const int16_t& operator[](size_t index) const;
-  int16_t& operator[](size_t index);
+  inline const int16_t& operator[](size_t index) const {
+    return array_[WrapIndex(index, begin_index_, capacity_)];
+  }
+
+  inline int16_t& operator[](size_t index) {
+    return array_[WrapIndex(index, begin_index_, capacity_)];
+  }
 
  private:
   static const size_t kDefaultInitialSize = 10;
 
+  // This method is used by the [] operators to calculate an index within the
+  // capacity of the array, but without using the modulo operation (%).
+  static inline size_t WrapIndex(size_t index,
+                                 size_t begin_index,
+                                 size_t capacity) {
+    RTC_DCHECK_GE(begin_index + index, index);  // Check for overflow.
+    const size_t ix = begin_index + index >= capacity
+                          ? begin_index + index - capacity
+                          : begin_index + index;
+    RTC_DCHECK_LT(ix, capacity);
+    return ix;
+  }
+
   void Reserve(size_t n);
 
   void InsertByPushBack(const int16_t* insert_this, size_t length,