Add copy of opus library in deps/third_party.

opus/silk/NLSF_unpack.c

+/***********************************************************************
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+***********************************************************************/
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "main.h"
+
+/* Unpack predictor values and indices for entropy coding tables */
+void silk_NLSF_unpack(
+          opus_int16            ec_ix[],                        /* O    Indices to entropy tables [ LPC_ORDER ]     */
+          opus_uint8            pred_Q8[],                      /* O    LSF predictor [ LPC_ORDER ]                 */
+    const silk_NLSF_CB_struct   *psNLSF_CB,                     /* I    Codebook object                             */
+    const opus_int              CB1_index                       /* I    Index of vector in first LSF codebook       */
+)
+{
+    opus_int   i;
+    opus_uint8 entry;
+    const opus_uint8 *ec_sel_ptr;
+
+    ec_sel_ptr = &psNLSF_CB->ec_sel[ CB1_index * psNLSF_CB->order / 2 ];
+    for( i = 0; i < psNLSF_CB->order; i += 2 ) {
+        entry = *ec_sel_ptr++;
+        ec_ix  [ i     ] = silk_SMULBB( silk_RSHIFT( entry, 1 ) & 7, 2 * NLSF_QUANT_MAX_AMPLITUDE + 1 );
+        pred_Q8[ i     ] = psNLSF_CB->pred_Q8[ i + ( entry & 1 ) * ( psNLSF_CB->order - 1 ) ];
+        ec_ix  [ i + 1 ] = silk_SMULBB( silk_RSHIFT( entry, 5 ) & 7, 2 * NLSF_QUANT_MAX_AMPLITUDE + 1 );
+        pred_Q8[ i + 1 ] = psNLSF_CB->pred_Q8[ i + ( silk_RSHIFT( entry, 4 ) & 1 ) * ( psNLSF_CB->order - 1 ) + 1 ];
+    }
+}
+