1 files changed, 49 insertions, 0 deletions
diff --git a/drivers/opus/silk/float/bwexpander_FLP.c b/drivers/opus/silk/float/bwexpander_FLP.c
new file mode 100644
index 0000000000..86154dc3f1
--- /dev/null
+++ b/drivers/opus/silk/float/bwexpander_FLP.c
@@ -0,0 +1,49 @@
+/***********************************************************************
+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 OPUS_HAVE_CONFIG_H
+#include "opus_config.h"
+#endif
+
+#include "SigProc_FLP.h"
+
+/* Chirp (bw expand) LP AR filter */
+void silk_bwexpander_FLP(
+    silk_float          *ar,                /* I/O  AR filter to be expanded (without leading 1)                */
+    const opus_int      d,                  /* I    length of ar                                                */
+    const silk_float    chirp               /* I    chirp factor (typically in range (0..1) )                   */
+)
+{
+    opus_int   i;
+    silk_float cfac = chirp;
+
+    for( i = 0; i < d - 1; i++ ) {
+        ar[ i ] *=  cfac;
+        cfac    *=  chirp;
+    }
+    ar[ d - 1 ] *=  cfac;
+}