Add clz functions (Count number of Leading Zero bits), 32-and 64-bit variants

webrtc/common_audio/signal_processing/signal_processing_unittest.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.
  */
 
@@ skipping 124 matching lines @@
           INT32_MIN, std::min<int64_t>(INT32_MAX, static_cast<int64_t>(a) - b));
       std::ostringstream ss;
       ss << a << " +/- " << b << ": sum " << sum << ", diff " << diff;
       SCOPED_TRACE(ss.str());
       EXPECT_EQ(sum, WebRtcSpl_AddSatW32(a, b));
       EXPECT_EQ(diff, WebRtcSpl_SubSatW32(a, b));
     }
   }
 }
 
+TEST_F(SplTest, CountLeadingZeros32) {
+  EXPECT_EQ(32, WebRtcSpl_CountLeadingZeros32(0));
+  EXPECT_EQ(32, WebRtcSpl_CountLeadingZeros32_NotBuiltin(0));
+  for (int i = 0; i < 32; ++i) {
+    const uint32_t single_one = uint32_t{1} << i;
+    const uint32_t all_ones = 2 * single_one - 1;
+    EXPECT_EQ(31 - i, WebRtcSpl_CountLeadingZeros32(single_one));
+    EXPECT_EQ(31 - i, WebRtcSpl_CountLeadingZeros32_NotBuiltin(single_one));
+    EXPECT_EQ(31 - i, WebRtcSpl_CountLeadingZeros32(all_ones));
+    EXPECT_EQ(31 - i, WebRtcSpl_CountLeadingZeros32_NotBuiltin(all_ones));
+  }
+}
+
+TEST_F(SplTest, CountLeadingZeros64) {
+  EXPECT_EQ(64, WebRtcSpl_CountLeadingZeros64(0));
+  EXPECT_EQ(64, WebRtcSpl_CountLeadingZeros64_NotBuiltin(0));
+  for (int i = 0; i < 64; ++i) {
+    const uint64_t single_one = uint64_t{1} << i;
+    const uint64_t all_ones = 2 * single_one - 1;
+    EXPECT_EQ(63 - i, WebRtcSpl_CountLeadingZeros64(single_one));
+    EXPECT_EQ(63 - i, WebRtcSpl_CountLeadingZeros64_NotBuiltin(single_one));
+    EXPECT_EQ(63 - i, WebRtcSpl_CountLeadingZeros64(all_ones));
+    EXPECT_EQ(63 - i, WebRtcSpl_CountLeadingZeros64_NotBuiltin(all_ones));
+  }
+}
+
 TEST_F(SplTest, MathOperationsTest) {
     int A = 1134567892;
     int32_t num = 117;
     int32_t den = -5;
     uint16_t denU = 5;
     EXPECT_EQ(33700, WebRtcSpl_Sqrt(A));
     EXPECT_EQ(33683, WebRtcSpl_SqrtFloor(A));
 
 
     EXPECT_EQ(-91772805, WebRtcSpl_DivResultInQ31(den, num));
@@ skipping 417 matching lines @@
   // 12-15 are skipped to account for the filter lag.
   for (size_t i = 0; i < 12; ++i) {
     EXPECT_EQ(kRefValue32kHz1, out_vector[i]);
     EXPECT_EQ(kRefValue16kHz1, out_vector_w16[i]);
   }
   for (size_t i = 16; i < 2 * kBlockSize; ++i) {
     EXPECT_EQ(kRefValue32kHz2, out_vector[i]);
     EXPECT_EQ(kRefValue16kHz2, out_vector_w16[i]);
   }
 }