1 files changed, 55 insertions, 0 deletions
diff --git a/third_party/libwebrtc/common_audio/signal_processing/filter_ma_fast_q12.c b/third_party/libwebrtc/common_audio/signal_processing/filter_ma_fast_q12.c
new file mode 100644
index 0000000000..329d47e14f
--- /dev/null
+++ b/third_party/libwebrtc/common_audio/signal_processing/filter_ma_fast_q12.c
@@ -0,0 +1,55 @@
+/*
+ *  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_FilterMAFastQ12().
+ * The description header can be found in signal_processing_library.h
+ *
+ */
+
+#include "common_audio/signal_processing/include/signal_processing_library.h"
+
+#include "rtc_base/sanitizer.h"
+
+void WebRtcSpl_FilterMAFastQ12(const int16_t* in_ptr,
+                               int16_t* out_ptr,
+                               const int16_t* B,
+                               size_t B_length,
+                               size_t length)
+{
+    size_t i, j;
+
+    rtc_MsanCheckInitialized(B, sizeof(B[0]), B_length);
+    rtc_MsanCheckInitialized(in_ptr - B_length + 1, sizeof(in_ptr[0]),
+                             B_length + length - 1);
+
+    for (i = 0; i < length; i++)
+    {
+        int32_t o = 0;
+
+        for (j = 0; j < B_length; j++)
+        {
+          // Negative overflow is permitted here, because this is
+          // auto-regressive filters, and the state for each batch run is
+          // stored in the "negative" positions of the output vector.
+          o += B[j] * in_ptr[(ptrdiff_t) i - (ptrdiff_t) j];
+        }
+
+        // If output is higher than 32768, saturate it. Same with negative side
+        // 2^27 = 134217728, which corresponds to 32768 in Q12
+
+        // Saturate the output
+        o = WEBRTC_SPL_SAT((int32_t)134215679, o, (int32_t)-134217728);
+
+        *out_ptr++ = (int16_t)((o + (int32_t)2048) >> 12);
+    }
+    return;
+}