Add copy of opus library in deps/third_party.

opus/silk/fixed/autocorr_FIX.c

+/***********************************************************************
+Copyright (c) 2006-2011, Skype Limited. All rights reserved.
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions
+are met:
+- Redistributions of source code must retain the above copyright notice,
+this list of conditions and the following disclaimer.
+- Redistributions in binary form must reproduce the above copyright
+notice, this list of conditions and the following disclaimer in the
+documentation and/or other materials provided with the distribution.
+- Neither the name of Internet Society, IETF or IETF Trust, nor the 
+names of specific contributors, may be used to endorse or promote
+products derived from this software without specific prior written
+permission.
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS “AS IS”
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.
+***********************************************************************/
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "SigProc_FIX.h"
+
+/* Compute autocorrelation */
+void silk_autocorr(
+    opus_int32                  *results,           /* O    Result (length correlationCount)                            */
+    opus_int                    *scale,             /* O    Scaling of the correlation vector                           */
+    const opus_int16            *inputData,         /* I    Input data to correlate                                     */
+    const opus_int              inputDataSize,      /* I    Length of input                                             */
+    const opus_int              correlationCount    /* I    Number of correlation taps to compute                       */
+)
+{
+    opus_int   i, lz, nRightShifts, corrCount;
+    opus_int64 corr64;
+
+    corrCount = silk_min_int( inputDataSize, correlationCount );
+
+    /* compute energy (zero-lag correlation) */
+    corr64 = silk_inner_prod16_aligned_64( inputData, inputData, inputDataSize );
+
+    /* deal with all-zero input data */
+    corr64 += 1;
+
+    /* number of leading zeros */
+    lz = silk_CLZ64( corr64 );
+
+    /* scaling: number of right shifts applied to correlations */
+    nRightShifts = 35 - lz;
+    *scale = nRightShifts;
+
+    if( nRightShifts <= 0 ) {
+        results[ 0 ] = silk_LSHIFT( (opus_int32)silk_CHECK_FIT32( corr64 ), -nRightShifts );
+
+        /* compute remaining correlations based on int32 inner product */
+          for( i = 1; i < corrCount; i++ ) {
+            results[ i ] = silk_LSHIFT( silk_inner_prod_aligned( inputData, inputData + i, inputDataSize - i ), -nRightShifts );
+        }
+    } else {
+        results[ 0 ] = (opus_int32)silk_CHECK_FIT32( silk_RSHIFT64( corr64, nRightShifts ) );
+
+        /* compute remaining correlations based on int64 inner product */
+          for( i = 1; i < corrCount; i++ ) {
+            results[ i ] =  (opus_int32)silk_CHECK_FIT32( silk_RSHIFT64( silk_inner_prod16_aligned_64( inputData, inputData + i, inputDataSize - i ), nRightShifts ) );
+        }
+    }
+}