1 files changed, 59 insertions, 0 deletions
diff --git a/third_party/webrtc/src/webrtc/common_audio/signal_processing/refl_coef_to_lpc.c b/third_party/webrtc/src/webrtc/common_audio/signal_processing/refl_coef_to_lpc.c
new file mode 100644
index 00000000..06a29b66
--- /dev/null
+++ b/third_party/webrtc/src/webrtc/common_audio/signal_processing/refl_coef_to_lpc.c
@@ -0,0 +1,59 @@
+/*
+ *  Copyright (c) 2011 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.
+ */
+
+
+/*
+ * This file contains the function WebRtcSpl_ReflCoefToLpc().
+ * The description header can be found in signal_processing_library.h
+ *
+ */
+
+#include "webrtc/common_audio/signal_processing/include/signal_processing_library.h"
+
+void WebRtcSpl_ReflCoefToLpc(const int16_t *k, int use_order, int16_t *a)
+{
+    int16_t any[WEBRTC_SPL_MAX_LPC_ORDER + 1];
+    int16_t *aptr, *aptr2, *anyptr;
+    const int16_t *kptr;
+    int m, i;
+
+    kptr = k;
+    *a = 4096; // i.e., (Word16_MAX >> 3)+1.
+    *any = *a;
+    a[1] = *k >> 3;
+
+    for (m = 1; m < use_order; m++)
+    {
+        kptr++;
+        aptr = a;
+        aptr++;
+        aptr2 = &a[m];
+        anyptr = any;
+        anyptr++;
+
+        any[m + 1] = *kptr >> 3;
+        for (i = 0; i < m; i++)
+        {
+            *anyptr = *aptr + (int16_t)((*aptr2 * *kptr) >> 15);
+            anyptr++;
+            aptr++;
+            aptr2--;
+        }
+
+        aptr = a;
+        anyptr = any;
+        for (i = 0; i < (m + 2); i++)
+        {
+            *aptr = *anyptr;
+            aptr++;
+            anyptr++;
+        }
+    }
+}