iLBC: Handle a case of bad input data

webrtc/modules/audio_coding/codecs/ilbc/decode.h

 /*
  *  Copyright (c) 2012 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.
  */
 
 /******************************************************************
 
  iLBC Speech Coder ANSI-C Source Code
 
  WebRtcIlbcfix_Decode.h
 
 ******************************************************************/
 
 #ifndef WEBRTC_MODULES_AUDIO_CODING_CODECS_ILBC_MAIN_SOURCE_DECODE_H_
 #define WEBRTC_MODULES_AUDIO_CODING_CODECS_ILBC_MAIN_SOURCE_DECODE_H_
 
 #include "defines.h"
 
 /*----------------------------------------------------------------*
  *  main decoder function
  *---------------------------------------------------------------*/
 
-void WebRtcIlbcfix_DecodeImpl(
-    int16_t *decblock,    /* (o) decoded signal block */
-    const uint16_t *bytes, /* (i) encoded signal bits */
-    IlbcDecoder *iLBCdec_inst, /* (i/o) the decoder state
+// Returns 0 on success, -1 on error.
+int WebRtcIlbcfix_DecodeImpl(
+    int16_t* decblock,         /* (o) decoded signal block */
+    const uint16_t* bytes,     /* (i) encoded signal bits */
+    IlbcDecoder* iLBCdec_inst, /* (i/o) the decoder state
                                            structure */
-    int16_t mode      /* (i) 0: bad packet, PLC,
-                                                                   1: normal */
-                           );
+    int16_t mode               /* (i) 0: bad packet, PLC,
+                                      1: normal */
+    ) WARN_UNUSED_RESULT;
 
 #endif